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putty/ssh.c

8048 строки
232 KiB
C
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#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include "putty.h"
#include "tree234.h"
#include "ssh.h"
#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif
#define SSH1_MSG_DISCONNECT 1 /* 0x1 */
#define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
#define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
#define SSH1_CMSG_USER 4 /* 0x4 */
#define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
#define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
#define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
#define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
#define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
#define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
#define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
#define SSH1_SMSG_SUCCESS 14 /* 0xe */
#define SSH1_SMSG_FAILURE 15 /* 0xf */
#define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
#define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
#define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
#define SSH1_CMSG_EOF 19 /* 0x13 */
#define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
#define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
#define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
#define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
#define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
#define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
#define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
#define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
#define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
#define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
#define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
#define SSH1_MSG_IGNORE 32 /* 0x20 */
#define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
#define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
#define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
#define SSH1_MSG_DEBUG 36 /* 0x24 */
#define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
#define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
#define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
#define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
#define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
#define SSH1_AUTH_TIS 5 /* 0x5 */
#define SSH1_AUTH_CCARD 16 /* 0x10 */
#define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
/* Mask for protoflags we will echo back to server if seen */
#define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
#define SSH2_MSG_DISCONNECT 1 /* 0x1 */
#define SSH2_MSG_IGNORE 2 /* 0x2 */
#define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
#define SSH2_MSG_DEBUG 4 /* 0x4 */
#define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
#define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
#define SSH2_MSG_KEXINIT 20 /* 0x14 */
#define SSH2_MSG_NEWKEYS 21 /* 0x15 */
#define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
#define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
#define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
#define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
#define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
#define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
#define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
#define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
#define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
#define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
#define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
#define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
#define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
#define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
#define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
#define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
#define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
#define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
#define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
#define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
#define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
#define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
#define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
/*
* Packet type contexts, so that ssh2_pkt_type can correctly decode
* the ambiguous type numbers back into the correct type strings.
*/
#define SSH2_PKTCTX_DHGROUP 0x0001
#define SSH2_PKTCTX_DHGEX 0x0002
#define SSH2_PKTCTX_KEX_MASK 0x000F
#define SSH2_PKTCTX_PUBLICKEY 0x0010
#define SSH2_PKTCTX_PASSWORD 0x0020
#define SSH2_PKTCTX_KBDINTER 0x0040
#define SSH2_PKTCTX_AUTH_MASK 0x00F0
#define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
#define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
#define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
#define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
#define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
#define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
#define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
#define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
#define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
#define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
#define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
#define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
#define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
#define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
#define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
static const char *const ssh2_disconnect_reasons[] = {
NULL,
"SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
"SSH_DISCONNECT_PROTOCOL_ERROR",
"SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
"SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
"SSH_DISCONNECT_MAC_ERROR",
"SSH_DISCONNECT_COMPRESSION_ERROR",
"SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
"SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
"SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
"SSH_DISCONNECT_CONNECTION_LOST",
"SSH_DISCONNECT_BY_APPLICATION",
"SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
"SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
"SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
"SSH_DISCONNECT_ILLEGAL_USER_NAME",
};
#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
#define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
#define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
/*
* Various remote-bug flags.
*/
#define BUG_CHOKES_ON_SSH1_IGNORE 1
#define BUG_SSH2_HMAC 2
#define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
#define BUG_CHOKES_ON_RSA 8
#define BUG_SSH2_RSA_PADDING 16
#define BUG_SSH2_DERIVEKEY 32
#define BUG_SSH2_REKEY 64
#define BUG_SSH2_PK_SESSIONID 128
#define translate(x) if (type == x) return #x
#define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
static char *ssh1_pkt_type(int type)
{
translate(SSH1_MSG_DISCONNECT);
translate(SSH1_SMSG_PUBLIC_KEY);
translate(SSH1_CMSG_SESSION_KEY);
translate(SSH1_CMSG_USER);
translate(SSH1_CMSG_AUTH_RSA);
translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
translate(SSH1_CMSG_AUTH_PASSWORD);
translate(SSH1_CMSG_REQUEST_PTY);
translate(SSH1_CMSG_WINDOW_SIZE);
translate(SSH1_CMSG_EXEC_SHELL);
translate(SSH1_CMSG_EXEC_CMD);
translate(SSH1_SMSG_SUCCESS);
translate(SSH1_SMSG_FAILURE);
translate(SSH1_CMSG_STDIN_DATA);
translate(SSH1_SMSG_STDOUT_DATA);
translate(SSH1_SMSG_STDERR_DATA);
translate(SSH1_CMSG_EOF);
translate(SSH1_SMSG_EXIT_STATUS);
translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
translate(SSH1_MSG_CHANNEL_DATA);
translate(SSH1_MSG_CHANNEL_CLOSE);
translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
translate(SSH1_SMSG_X11_OPEN);
translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
translate(SSH1_MSG_PORT_OPEN);
translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
translate(SSH1_SMSG_AGENT_OPEN);
translate(SSH1_MSG_IGNORE);
translate(SSH1_CMSG_EXIT_CONFIRMATION);
translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
translate(SSH1_MSG_DEBUG);
translate(SSH1_CMSG_REQUEST_COMPRESSION);
translate(SSH1_CMSG_AUTH_TIS);
translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
translate(SSH1_CMSG_AUTH_CCARD);
translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
return "unknown";
}
static char *ssh2_pkt_type(int pkt_ctx, int type)
{
translate(SSH2_MSG_DISCONNECT);
translate(SSH2_MSG_IGNORE);
translate(SSH2_MSG_UNIMPLEMENTED);
translate(SSH2_MSG_DEBUG);
translate(SSH2_MSG_SERVICE_REQUEST);
translate(SSH2_MSG_SERVICE_ACCEPT);
translate(SSH2_MSG_KEXINIT);
translate(SSH2_MSG_NEWKEYS);
translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
translate(SSH2_MSG_USERAUTH_REQUEST);
translate(SSH2_MSG_USERAUTH_FAILURE);
translate(SSH2_MSG_USERAUTH_SUCCESS);
translate(SSH2_MSG_USERAUTH_BANNER);
translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
translate(SSH2_MSG_GLOBAL_REQUEST);
translate(SSH2_MSG_REQUEST_SUCCESS);
translate(SSH2_MSG_REQUEST_FAILURE);
translate(SSH2_MSG_CHANNEL_OPEN);
translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
translate(SSH2_MSG_CHANNEL_DATA);
translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
translate(SSH2_MSG_CHANNEL_EOF);
translate(SSH2_MSG_CHANNEL_CLOSE);
translate(SSH2_MSG_CHANNEL_REQUEST);
translate(SSH2_MSG_CHANNEL_SUCCESS);
translate(SSH2_MSG_CHANNEL_FAILURE);
return "unknown";
}
#undef translate
#undef translatec
#define GET_32BIT(cp) \
(((unsigned long)(unsigned char)(cp)[0] << 24) | \
((unsigned long)(unsigned char)(cp)[1] << 16) | \
((unsigned long)(unsigned char)(cp)[2] << 8) | \
((unsigned long)(unsigned char)(cp)[3]))
#define PUT_32BIT(cp, value) { \
(cp)[0] = (unsigned char)((value) >> 24); \
(cp)[1] = (unsigned char)((value) >> 16); \
(cp)[2] = (unsigned char)((value) >> 8); \
(cp)[3] = (unsigned char)(value); }
/* Enumeration values for fields in SSH-1 packets */
enum {
PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM,
/* These values are for communicating relevant semantics of
* fields to the packet logging code. */
PKTT_OTHER, PKTT_PASSWORD, PKTT_DATA
};
/*
* Coroutine mechanics for the sillier bits of the code. If these
* macros look impenetrable to you, you might find it helpful to
* read
*
* http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
*
* which explains the theory behind these macros.
*
* In particular, if you are getting `case expression not constant'
* errors when building with MS Visual Studio, this is because MS's
* Edit and Continue debugging feature causes their compiler to
* violate ANSI C. To disable Edit and Continue debugging:
*
* - right-click ssh.c in the FileView
* - click Settings
* - select the C/C++ tab and the General category
* - under `Debug info:', select anything _other_ than `Program
* Database for Edit and Continue'.
*/
#define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
#define crState(t) \
struct t *s; \
if (!ssh->t) ssh->t = snew(struct t); \
s = ssh->t;
#define crFinish(z) } *crLine = 0; return (z); }
#define crFinishV } *crLine = 0; return; }
#define crReturn(z) \
do {\
*crLine =__LINE__; return (z); case __LINE__:;\
} while (0)
#define crReturnV \
do {\
*crLine=__LINE__; return; case __LINE__:;\
} while (0)
#define crStop(z) do{ *crLine = 0; return (z); }while(0)
#define crStopV do{ *crLine = 0; return; }while(0)
#define crWaitUntil(c) do { crReturn(0); } while (!(c))
#define crWaitUntilV(c) do { crReturnV; } while (!(c))
typedef struct ssh_tag *Ssh;
struct Packet;
static struct Packet *ssh2_pkt_init(int pkt_type);
static void ssh2_pkt_addbool(struct Packet *, unsigned char value);
static void ssh2_pkt_adduint32(struct Packet *, unsigned long value);
static void ssh2_pkt_addstring_start(struct Packet *);
static void ssh2_pkt_addstring_str(struct Packet *, char *data);
static void ssh2_pkt_addstring_data(struct Packet *, char *data, int len);
static void ssh2_pkt_addstring(struct Packet *, char *data);
static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
static void ssh2_pkt_addmp(struct Packet *, Bignum b);
static int ssh2_pkt_construct(Ssh, struct Packet *);
static void ssh2_pkt_send(Ssh, struct Packet *);
static void ssh2_pkt_send_noqueue(Ssh, struct Packet *);
static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
struct Packet *pktin);
static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
struct Packet *pktin);
/*
* Buffer management constants. There are several of these for
* various different purposes:
*
* - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
* on a local data stream before we throttle the whole SSH
* connection (in SSH1 only). Throttling the whole connection is
* pretty drastic so we set this high in the hope it won't
* happen very often.
*
* - SSH_MAX_BACKLOG is the amount of backlog that must build up
* on the SSH connection itself before we defensively throttle
* _all_ local data streams. This is pretty drastic too (though
* thankfully unlikely in SSH2 since the window mechanism should
* ensure that the server never has any need to throttle its end
* of the connection), so we set this high as well.
*
* - OUR_V2_WINSIZE is the maximum window size we present on SSH2
* channels.
*/
#define SSH1_BUFFER_LIMIT 32768
#define SSH_MAX_BACKLOG 32768
#define OUR_V2_WINSIZE 16384
#define OUR_V2_MAXPKT 0x4000UL
const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
static void *nullmac_make_context(void)
{
return NULL;
}
static void nullmac_free_context(void *handle)
{
}
static void nullmac_key(void *handle, unsigned char *key)
{
}
static void nullmac_generate(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
}
static int nullmac_verify(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
return 1;
}
const static struct ssh_mac ssh_mac_none = {
nullmac_make_context, nullmac_free_context, nullmac_key,
nullmac_generate, nullmac_verify, "none", 0
};
const static struct ssh_mac *macs[] = {
&ssh_sha1, &ssh_md5, &ssh_mac_none
};
const static struct ssh_mac *buggymacs[] = {
&ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
};
static void *ssh_comp_none_init(void)
{
return NULL;
}
static void ssh_comp_none_cleanup(void *handle)
{
}
static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
unsigned char **outblock, int *outlen)
{
return 0;
}
static int ssh_comp_none_disable(void *handle)
{
return 0;
}
const static struct ssh_compress ssh_comp_none = {
"none",
ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
ssh_comp_none_disable, NULL
};
extern const struct ssh_compress ssh_zlib;
const static struct ssh_compress *compressions[] = {
&ssh_zlib, &ssh_comp_none
};
enum { /* channel types */
CHAN_MAINSESSION,
CHAN_X11,
CHAN_AGENT,
CHAN_SOCKDATA,
CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
};
/*
* 2-3-4 tree storing channels.
*/
struct ssh_channel {
Ssh ssh; /* pointer back to main context */
unsigned remoteid, localid;
int type;
/* True if we opened this channel but server hasn't confirmed. */
int halfopen;
/*
* In SSH1, this value contains four bits:
*
* 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
* 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
* 4 We have received SSH1_MSG_CHANNEL_CLOSE.
* 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
*
* A channel is completely finished with when all four bits are set.
*/
int closes;
union {
struct ssh1_data_channel {
int throttling;
} v1;
struct ssh2_data_channel {
bufchain outbuffer;
unsigned remwindow, remmaxpkt;
unsigned locwindow;
} v2;
} v;
union {
struct ssh_agent_channel {
unsigned char *message;
unsigned char msglen[4];
unsigned lensofar, totallen;
} a;
struct ssh_x11_channel {
Socket s;
} x11;
struct ssh_pfd_channel {
Socket s;
} pfd;
} u;
};
/*
* 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
* 2 use this structure in different ways, reflecting SSH 2's
* altogether saner approach to port forwarding.
*
* In SSH 1, you arrange a remote forwarding by sending the server
* the remote port number, and the local destination host:port.
* When a connection comes in, the server sends you back that
* host:port pair, and you connect to it. This is a ready-made
* security hole if you're not on the ball: a malicious server
* could send you back _any_ host:port pair, so if you trustingly
* connect to the address it gives you then you've just opened the
* entire inside of your corporate network just by connecting
* through it to a dodgy SSH server. Hence, we must store a list of
* host:port pairs we _are_ trying to forward to, and reject a
* connection request from the server if it's not in the list.
*
* In SSH 2, each side of the connection minds its own business and
* doesn't send unnecessary information to the other. You arrange a
* remote forwarding by sending the server just the remote port
* number. When a connection comes in, the server tells you which
* of its ports was connected to; and _you_ have to remember what
* local host:port pair went with that port number.
*
* Hence, in SSH 1 this structure is indexed by destination
* host:port pair, whereas in SSH 2 it is indexed by source port.
*/
struct ssh_portfwd; /* forward declaration */
struct ssh_rportfwd {
unsigned sport, dport;
char dhost[256];
char *sportdesc;
struct ssh_portfwd *pfrec;
};
#define free_rportfwd(pf) ( \
((pf) ? (sfree((pf)->sportdesc)) : (void)0 ), sfree(pf) )
/*
* Separately to the rportfwd tree (which is for looking up port
* open requests from the server), a tree of _these_ structures is
* used to keep track of all the currently open port forwardings,
* so that we can reconfigure in mid-session if the user requests
* it.
*/
struct ssh_portfwd {
enum { DESTROY, KEEP, CREATE } status;
int type;
unsigned sport, dport;
char *saddr, *daddr;
char *sserv, *dserv;
struct ssh_rportfwd *remote;
int addressfamily;
void *local;
};
#define free_portfwd(pf) ( \
((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr), \
sfree((pf)->sserv), sfree((pf)->dserv)) : (void)0 ), sfree(pf) )
struct Packet {
long length;
long forcepad; /* Force padding to at least this length */
int type;
unsigned long sequence;
unsigned char *data;
unsigned char *body;
long savedpos;
long maxlen;
long encrypted_len; /* for SSH2 total-size counting */
/*
* State associated with packet logging
*/
int logmode;
int nblanks;
struct logblank_t *blanks;
};
static void ssh1_protocol(Ssh ssh, void *vin, int inlen,
struct Packet *pktin);
static void ssh2_protocol(Ssh ssh, void *vin, int inlen,
struct Packet *pktin);
static void ssh1_protocol_setup(Ssh ssh);
static void ssh2_protocol_setup(Ssh ssh);
static void ssh_size(void *handle, int width, int height);
static void ssh_special(void *handle, Telnet_Special);
static int ssh2_try_send(struct ssh_channel *c);
static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
static int ssh_sendbuffer(void *handle);
static int ssh_do_close(Ssh ssh, int notify_exit);
static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
static int ssh2_pkt_getbool(struct Packet *pkt);
static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length);
static void ssh2_timer(void *ctx, long now);
static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
struct Packet *pktin);
struct rdpkt1_state_tag {
long len, pad, biglen, to_read;
unsigned long realcrc, gotcrc;
unsigned char *p;
int i;
int chunk;
struct Packet *pktin;
};
struct rdpkt2_state_tag {
long len, pad, payload, packetlen, maclen;
int i;
int cipherblk;
unsigned long incoming_sequence;
struct Packet *pktin;
};
typedef void (*handler_fn_t)(Ssh ssh, struct Packet *pktin);
typedef void (*chandler_fn_t)(Ssh ssh, struct Packet *pktin, void *ctx);
struct queued_handler;
struct queued_handler {
int msg1, msg2;
chandler_fn_t handler;
void *ctx;
struct queued_handler *next;
};
struct ssh_tag {
const struct plug_function_table *fn;
/* the above field _must_ be first in the structure */
SHA_State exhash, exhashbase;
Socket s;
void *ldisc;
void *logctx;
unsigned char session_key[32];
int v1_compressing;
int v1_remote_protoflags;
int v1_local_protoflags;
int agentfwd_enabled;
int X11_fwd_enabled;
int remote_bugs;
const struct ssh_cipher *cipher;
void *v1_cipher_ctx;
void *crcda_ctx;
const struct ssh2_cipher *cscipher, *sccipher;
void *cs_cipher_ctx, *sc_cipher_ctx;
const struct ssh_mac *csmac, *scmac;
void *cs_mac_ctx, *sc_mac_ctx;
const struct ssh_compress *cscomp, *sccomp;
void *cs_comp_ctx, *sc_comp_ctx;
const struct ssh_kex *kex;
const struct ssh_signkey *hostkey;
unsigned char v2_session_id[20];
void *kex_ctx;
char *savedhost;
int savedport;
int send_ok;
int echoing, editing;
void *frontend;
int ospeed, ispeed; /* temporaries */
int term_width, term_height;
tree234 *channels; /* indexed by local id */
struct ssh_channel *mainchan; /* primary session channel */
int exitcode;
int close_expected;
tree234 *rportfwds, *portfwds;
enum {
SSH_STATE_PREPACKET,
SSH_STATE_BEFORE_SIZE,
SSH_STATE_INTERMED,
SSH_STATE_SESSION,
SSH_STATE_CLOSED
} state;
int size_needed, eof_needed;
struct Packet **queue;
int queuelen, queuesize;
int queueing;
unsigned char *deferred_send_data;
int deferred_len, deferred_size;
/*
* Gross hack: pscp will try to start SFTP but fall back to
* scp1 if that fails. This variable is the means by which
* scp.c can reach into the SSH code and find out which one it
* got.
*/
int fallback_cmd;
/*
* Used for username and password input.
*/
char *userpass_input_buffer;
int userpass_input_buflen;
int userpass_input_bufpos;
int userpass_input_echo;
int pkt_ctx;
void *x11auth;
int version;
int v1_throttle_count;
int overall_bufsize;
int throttled_all;
int v1_stdout_throttling;
unsigned long v2_outgoing_sequence;
int ssh1_rdpkt_crstate;
int ssh2_rdpkt_crstate;
int do_ssh_init_crstate;
int ssh_gotdata_crstate;
int do_ssh1_login_crstate;
int do_ssh1_connection_crstate;
int do_ssh2_transport_crstate;
int do_ssh2_authconn_crstate;
void *do_ssh_init_state;
void *do_ssh1_login_state;
void *do_ssh2_transport_state;
void *do_ssh2_authconn_state;
struct rdpkt1_state_tag rdpkt1_state;
struct rdpkt2_state_tag rdpkt2_state;
/* ssh1 and ssh2 use this for different things, but both use it */
int protocol_initial_phase_done;
void (*protocol) (Ssh ssh, void *vin, int inlen,
struct Packet *pkt);
struct Packet *(*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
/*
* We maintain a full _copy_ of a Config structure here, not
* merely a pointer to it. That way, when we're passed a new
* one for reconfiguration, we can check the differences and
* potentially reconfigure port forwardings etc in mid-session.
*/
Config cfg;
/*
* Used to transfer data back from async agent callbacks.
*/
void *agent_response;
int agent_response_len;
/*
* Dispatch table for packet types that we may have to deal
* with at any time.
*/
handler_fn_t packet_dispatch[256];
/*
* Queues of one-off handler functions for success/failure
* indications from a request.
*/
struct queued_handler *qhead, *qtail;
/*
* This module deals with sending keepalives.
*/
Pinger pinger;
/*
* Track incoming and outgoing data sizes and time, for
* size-based rekeys.
*/
unsigned long incoming_data_size, outgoing_data_size, deferred_data_size;
unsigned long max_data_size;
int kex_in_progress;
long next_rekey, last_rekey;
char *deferred_rekey_reason; /* points to STATIC string; don't free */
};
#define logevent(s) logevent(ssh->frontend, s)
/* logevent, only printf-formatted. */
static void logeventf(Ssh ssh, const char *fmt, ...)
{
va_list ap;
char *buf;
va_start(ap, fmt);
buf = dupvprintf(fmt, ap);
va_end(ap);
logevent(buf);
sfree(buf);
}
#define bombout(msg) \
do { \
char *text = dupprintf msg; \
ssh_do_close(ssh, FALSE); \
logevent(text); \
connection_fatal(ssh->frontend, "%s", text); \
sfree(text); \
} while (0)
/* Functions to leave bits out of the SSH packet log file. */
static void dont_log_password(Ssh ssh, struct Packet *pkt, int blanktype)
{
if (ssh->cfg.logomitpass)
pkt->logmode = blanktype;
}
static void dont_log_data(Ssh ssh, struct Packet *pkt, int blanktype)
{
if (ssh->cfg.logomitdata)
pkt->logmode = blanktype;
}
static void end_log_omission(Ssh ssh, struct Packet *pkt)
{
pkt->logmode = PKTLOG_EMIT;
}
static int ssh_channelcmp(void *av, void *bv)
{
struct ssh_channel *a = (struct ssh_channel *) av;
struct ssh_channel *b = (struct ssh_channel *) bv;
if (a->localid < b->localid)
return -1;
if (a->localid > b->localid)
return +1;
return 0;
}
static int ssh_channelfind(void *av, void *bv)
{
unsigned *a = (unsigned *) av;
struct ssh_channel *b = (struct ssh_channel *) bv;
if (*a < b->localid)
return -1;
if (*a > b->localid)
return +1;
return 0;
}
static int ssh_rportcmp_ssh1(void *av, void *bv)
{
struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
int i;
if ( (i = strcmp(a->dhost, b->dhost)) != 0)
return i < 0 ? -1 : +1;
if (a->dport > b->dport)
return +1;
if (a->dport < b->dport)
return -1;
return 0;
}
static int ssh_rportcmp_ssh2(void *av, void *bv)
{
struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
if (a->sport > b->sport)
return +1;
if (a->sport < b->sport)
return -1;
return 0;
}
/*
* Special form of strcmp which can cope with NULL inputs. NULL is
* defined to sort before even the empty string.
*/
static int nullstrcmp(const char *a, const char *b)
{
if (a == NULL && b == NULL)
return 0;
if (a == NULL)
return -1;
if (b == NULL)
return +1;
return strcmp(a, b);
}
static int ssh_portcmp(void *av, void *bv)
{
struct ssh_portfwd *a = (struct ssh_portfwd *) av;
struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
int i;
if (a->type > b->type)
return +1;
if (a->type < b->type)
return -1;
if (a->addressfamily > b->addressfamily)
return +1;
if (a->addressfamily < b->addressfamily)
return -1;
if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
return i < 0 ? -1 : +1;
if (a->sport > b->sport)
return +1;
if (a->sport < b->sport)
return -1;
if (a->type != 'D') {
if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
return i < 0 ? -1 : +1;
if (a->dport > b->dport)
return +1;
if (a->dport < b->dport)
return -1;
}
return 0;
}
static int alloc_channel_id(Ssh ssh)
{
const unsigned CHANNEL_NUMBER_OFFSET = 256;
unsigned low, high, mid;
int tsize;
struct ssh_channel *c;
/*
* First-fit allocation of channel numbers: always pick the
* lowest unused one. To do this, binary-search using the
* counted B-tree to find the largest channel ID which is in a
* contiguous sequence from the beginning. (Precisely
* everything in that sequence must have ID equal to its tree
* index plus CHANNEL_NUMBER_OFFSET.)
*/
tsize = count234(ssh->channels);
low = -1;
high = tsize;
while (high - low > 1) {
mid = (high + low) / 2;
c = index234(ssh->channels, mid);
if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
low = mid; /* this one is fine */
else
high = mid; /* this one is past it */
}
/*
* Now low points to either -1, or the tree index of the
* largest ID in the initial sequence.
*/
{
unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
}
return low + 1 + CHANNEL_NUMBER_OFFSET;
}
static void c_write(Ssh ssh, const char *buf, int len)
{
if ((flags & FLAG_STDERR)) {
int i;
for (i = 0; i < len; i++)
if (buf[i] != '\r')
fputc(buf[i], stderr);
return;
}
from_backend(ssh->frontend, 1, buf, len);
}
static void c_write_untrusted(Ssh ssh, const char *buf, int len)
{
int i;
for (i = 0; i < len; i++) {
if (buf[i] == '\n')
c_write(ssh, "\r\n", 2);
else if ((buf[i] & 0x60) || (buf[i] == '\r'))
c_write(ssh, buf + i, 1);
}
}
static void c_write_str(Ssh ssh, const char *buf)
{
c_write(ssh, buf, strlen(buf));
}
static void ssh_free_packet(struct Packet *pkt)
{
sfree(pkt->data);
sfree(pkt);
}
static struct Packet *ssh_new_packet(void)
{
struct Packet *pkt = snew(struct Packet);
pkt->data = NULL;
pkt->maxlen = 0;
pkt->logmode = PKTLOG_EMIT;
pkt->nblanks = 0;
pkt->blanks = NULL;
return pkt;
}
/*
* Collect incoming data in the incoming packet buffer.
* Decipher and verify the packet when it is completely read.
* Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
* Update the *data and *datalen variables.
* Return a Packet structure when a packet is completed.
*/
static struct Packet *ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
{
struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
crBegin(ssh->ssh1_rdpkt_crstate);
st->pktin = ssh_new_packet();
st->pktin->type = 0;
st->pktin->length = 0;
for (st->i = st->len = 0; st->i < 4; st->i++) {
while ((*datalen) == 0)
crReturn(NULL);
st->len = (st->len << 8) + **data;
(*data)++, (*datalen)--;
}
st->pad = 8 - (st->len % 8);
st->biglen = st->len + st->pad;
st->pktin->length = st->len - 5;
if (st->biglen < 0) {
bombout(("Extremely large packet length from server suggests"
" data stream corruption"));
ssh_free_packet(st->pktin);
crStop(NULL);
}
st->pktin->maxlen = st->biglen;
st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char);
st->to_read = st->biglen;
st->p = st->pktin->data;
while (st->to_read > 0) {
st->chunk = st->to_read;
while ((*datalen) == 0)
crReturn(NULL);
if (st->chunk > (*datalen))
st->chunk = (*datalen);
memcpy(st->p, *data, st->chunk);
*data += st->chunk;
*datalen -= st->chunk;
st->p += st->chunk;
st->to_read -= st->chunk;
}
if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data,
st->biglen, NULL)) {
bombout(("Network attack (CRC compensation) detected!"));
ssh_free_packet(st->pktin);
crStop(NULL);
}
if (ssh->cipher)
ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen);
st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4);
st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4);
if (st->gotcrc != st->realcrc) {
bombout(("Incorrect CRC received on packet"));
ssh_free_packet(st->pktin);
crStop(NULL);
}
st->pktin->body = st->pktin->data + st->pad + 1;
st->pktin->savedpos = 0;
if (ssh->v1_compressing) {
unsigned char *decompblk;
int decomplen;
if (!zlib_decompress_block(ssh->sc_comp_ctx,
st->pktin->body - 1, st->pktin->length + 1,
&decompblk, &decomplen)) {
bombout(("Zlib decompression encountered invalid data"));
ssh_free_packet(st->pktin);
crStop(NULL);
}
if (st->pktin->maxlen < st->pad + decomplen) {
st->pktin->maxlen = st->pad + decomplen;
st->pktin->data = sresize(st->pktin->data,
st->pktin->maxlen + APIEXTRA,
unsigned char);
st->pktin->body = st->pktin->data + st->pad + 1;
}
memcpy(st->pktin->body - 1, decompblk, decomplen);
sfree(decompblk);
st->pktin->length = decomplen - 1;
}
st->pktin->type = st->pktin->body[-1];
/*
* Log incoming packet, possibly omitting sensitive fields.
*/
if (ssh->logctx) {
int nblanks = 0;
struct logblank_t blank;
if (ssh->cfg.logomitdata) {
int do_blank = FALSE, blank_prefix = 0;
/* "Session data" packets - omit the data field */
if ((st->pktin->type == SSH1_SMSG_STDOUT_DATA) ||
(st->pktin->type == SSH1_SMSG_STDERR_DATA)) {
do_blank = TRUE; blank_prefix = 0;
} else if (st->pktin->type == SSH1_MSG_CHANNEL_DATA) {
do_blank = TRUE; blank_prefix = 4;
}
if (do_blank) {
blank.offset = blank_prefix;
blank.len = st->pktin->length;
blank.type = PKTLOG_OMIT;
nblanks = 1;
}
}
log_packet(ssh->logctx,
PKT_INCOMING, st->pktin->type,
ssh1_pkt_type(st->pktin->type),
st->pktin->body, st->pktin->length,
nblanks, &blank);
}
crFinish(st->pktin);
}
static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
{
struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
crBegin(ssh->ssh2_rdpkt_crstate);
st->pktin = ssh_new_packet();
st->pktin->type = 0;
st->pktin->length = 0;
if (ssh->sccipher)
st->cipherblk = ssh->sccipher->blksize;
else
st->cipherblk = 8;
if (st->cipherblk < 8)
st->cipherblk = 8;
st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
/*
* Acquire and decrypt the first block of the packet. This will
* contain the length and padding details.
*/
for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
while ((*datalen) == 0)
crReturn(NULL);
st->pktin->data[st->i] = *(*data)++;
(*datalen)--;
}
if (ssh->sccipher)
ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
st->pktin->data, st->cipherblk);
/*
* Now get the length and padding figures.
*/
st->len = GET_32BIT(st->pktin->data);
st->pad = st->pktin->data[4];
/*
* _Completely_ silly lengths should be stomped on before they
* do us any more damage.
*/
if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
bombout(("Incoming packet was garbled on decryption"));
ssh_free_packet(st->pktin);
crStop(NULL);
}
/*
* This enables us to deduce the payload length.
*/
st->payload = st->len - st->pad - 1;
st->pktin->length = st->payload + 5;
/*
* So now we can work out the total packet length.
*/
st->packetlen = st->len + 4;
st->maclen = ssh->scmac ? ssh->scmac->len : 0;
/*
* Allocate memory for the rest of the packet.
*/
st->pktin->maxlen = st->packetlen + st->maclen;
st->pktin->data = sresize(st->pktin->data,
st->pktin->maxlen + APIEXTRA,
unsigned char);
/*
* Read and decrypt the remainder of the packet.
*/
for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
st->i++) {
while ((*datalen) == 0)
crReturn(NULL);
st->pktin->data[st->i] = *(*data)++;
(*datalen)--;
}
/* Decrypt everything _except_ the MAC. */
if (ssh->sccipher)
ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
st->pktin->data + st->cipherblk,
st->packetlen - st->cipherblk);
st->pktin->encrypted_len = st->packetlen;
/*
* Check the MAC.
*/
if (ssh->scmac
&& !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data, st->len + 4,
st->incoming_sequence)) {
bombout(("Incorrect MAC received on packet"));
ssh_free_packet(st->pktin);
crStop(NULL);
}
st->pktin->sequence = st->incoming_sequence++;
/*
* Decompress packet payload.
*/
{
unsigned char *newpayload;
int newlen;
if (ssh->sccomp &&
ssh->sccomp->decompress(ssh->sc_comp_ctx,
st->pktin->data + 5, st->pktin->length - 5,
&newpayload, &newlen)) {
if (st->pktin->maxlen < newlen + 5) {
st->pktin->maxlen = newlen + 5;
st->pktin->data = sresize(st->pktin->data,
st->pktin->maxlen + APIEXTRA,
unsigned char);
}
st->pktin->length = 5 + newlen;
memcpy(st->pktin->data + 5, newpayload, newlen);
sfree(newpayload);
}
}
st->pktin->savedpos = 6;
st->pktin->body = st->pktin->data;
st->pktin->type = st->pktin->data[5];
/*
* Log incoming packet, possibly omitting sensitive fields.
*/
if (ssh->logctx) {
int nblanks = 0;
struct logblank_t blank;
if (ssh->cfg.logomitdata) {
int do_blank = FALSE, blank_prefix = 0;
/* "Session data" packets - omit the data field */
if (st->pktin->type == SSH2_MSG_CHANNEL_DATA) {
do_blank = TRUE; blank_prefix = 4;
} else if (st->pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
do_blank = TRUE; blank_prefix = 8;
}
if (do_blank) {
blank.offset = blank_prefix;
blank.len = (st->pktin->length-6) - blank_prefix;
blank.type = PKTLOG_OMIT;
nblanks = 1;
}
}
log_packet(ssh->logctx, PKT_INCOMING, st->pktin->type,
ssh2_pkt_type(ssh->pkt_ctx, st->pktin->type),
st->pktin->data+6, st->pktin->length-6,
nblanks, &blank);
}
crFinish(st->pktin);
}
static void ssh1_pktout_size(struct Packet *pkt, int len)
{
int pad, biglen;
len += 5; /* type and CRC */
pad = 8 - (len % 8);
biglen = len + pad;
pkt->length = len - 5;
if (pkt->maxlen < biglen) {
pkt->maxlen = biglen;
pkt->data = sresize(pkt->data, biglen + 4 + APIEXTRA, unsigned char);
}
pkt->body = pkt->data + 4 + pad + 1;
}
static struct Packet *s_wrpkt_start(int type, int len)
{
struct Packet *pkt = ssh_new_packet();
ssh1_pktout_size(pkt, len);
pkt->type = type;
/* Initialise log omission state */
pkt->nblanks = 0;
pkt->blanks = NULL;
return pkt;
}
static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt)
{
int pad, biglen, i;
unsigned long crc;
#ifdef __SC__
/*
* XXX various versions of SC (including 8.8.4) screw up the
* register allocation in this function and use the same register
* (D6) for len and as a temporary, with predictable results. The
* following sledgehammer prevents this.
*/
volatile
#endif
int len;
pkt->body[-1] = pkt->type;
if (ssh->logctx)
log_packet(ssh->logctx, PKT_OUTGOING, pkt->type,
ssh1_pkt_type(pkt->type),
pkt->body, pkt->length,
pkt->nblanks, pkt->blanks);
sfree(pkt->blanks); pkt->blanks = NULL;
pkt->nblanks = 0;
if (ssh->v1_compressing) {
unsigned char *compblk;
int complen;
zlib_compress_block(ssh->cs_comp_ctx,
pkt->body - 1, pkt->length + 1,
&compblk, &complen);
ssh1_pktout_size(pkt, complen - 1);
memcpy(pkt->body - 1, compblk, complen);
sfree(compblk);
}
len = pkt->length + 5; /* type and CRC */
pad = 8 - (len % 8);
biglen = len + pad;
for (i = 0; i < pad; i++)
pkt->data[i + 4] = random_byte();
crc = crc32_compute(pkt->data + 4, biglen - 4);
PUT_32BIT(pkt->data + biglen, crc);
PUT_32BIT(pkt->data, len);
if (ssh->cipher)
ssh->cipher->encrypt(ssh->v1_cipher_ctx, pkt->data + 4, biglen);
return biglen + 4;
}
static void s_wrpkt(Ssh ssh, struct Packet *pkt)
{
int len, backlog;
len = s_wrpkt_prepare(ssh, pkt);
backlog = sk_write(ssh->s, (char *)pkt->data, len);
if (backlog > SSH_MAX_BACKLOG)
ssh_throttle_all(ssh, 1, backlog);
}
static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt)
{
int len;
len = s_wrpkt_prepare(ssh, pkt);
if (ssh->deferred_len + len > ssh->deferred_size) {
ssh->deferred_size = ssh->deferred_len + len + 128;
ssh->deferred_send_data = sresize(ssh->deferred_send_data,
ssh->deferred_size,
unsigned char);
}
memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->data, len);
ssh->deferred_len += len;
}
/*
* Construct a packet with the specified contents.
*/
static struct Packet *construct_packet(Ssh ssh, int pkttype,
va_list ap1, va_list ap2)
{
unsigned char *p, *argp, argchar;
unsigned long argint;
int pktlen, argtype, arglen;
Bignum bn;
struct Packet *pkt;
pktlen = 0;
while ((argtype = va_arg(ap1, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
(void) va_arg(ap1, int);
pktlen += 4;
break;
case PKT_CHAR:
(void) va_arg(ap1, int);
pktlen++;
break;
case PKT_DATA:
(void) va_arg(ap1, unsigned char *);
arglen = va_arg(ap1, int);
pktlen += arglen;
break;
case PKT_STR:
argp = va_arg(ap1, unsigned char *);
arglen = strlen((char *)argp);
pktlen += 4 + arglen;
break;
case PKT_BIGNUM:
bn = va_arg(ap1, Bignum);
pktlen += ssh1_bignum_length(bn);
break;
case PKTT_PASSWORD:
case PKTT_DATA:
case PKTT_OTHER:
/* ignore this pass */
break;
default:
assert(0);
}
}
pkt = s_wrpkt_start(pkttype, pktlen);
p = pkt->body;
while ((argtype = va_arg(ap2, int)) != PKT_END) {
int offset = p - pkt->body, len = 0;
switch (argtype) {
/* Actual fields in the packet */
case PKT_INT:
argint = va_arg(ap2, int);
PUT_32BIT(p, argint);
len = 4;
break;
case PKT_CHAR:
argchar = (unsigned char) va_arg(ap2, int);
*p = argchar;
len = 1;
break;
case PKT_DATA:
argp = va_arg(ap2, unsigned char *);
arglen = va_arg(ap2, int);
memcpy(p, argp, arglen);
len = arglen;
break;
case PKT_STR:
argp = va_arg(ap2, unsigned char *);
arglen = strlen((char *)argp);
PUT_32BIT(p, arglen);
memcpy(p + 4, argp, arglen);
len = arglen + 4;
break;
case PKT_BIGNUM:
bn = va_arg(ap2, Bignum);
len = ssh1_write_bignum(p, bn);
break;
/* Tokens for modifications to packet logging */
case PKTT_PASSWORD:
dont_log_password(ssh, pkt, PKTLOG_BLANK);
break;
case PKTT_DATA:
dont_log_data(ssh, pkt, PKTLOG_OMIT);
break;
case PKTT_OTHER:
end_log_omission(ssh, pkt);
break;
}
p += len;
/* Deal with logfile omission, if required. */
if (len && (pkt->logmode != PKTLOG_EMIT)) {
pkt->nblanks++;
pkt->blanks = sresize(pkt->blanks, pkt->nblanks,
struct logblank_t);
pkt->blanks[pkt->nblanks-1].offset = offset;
pkt->blanks[pkt->nblanks-1].len = len;
pkt->blanks[pkt->nblanks-1].type = pkt->logmode;
}
}
return pkt;
}
static void send_packet(Ssh ssh, int pkttype, ...)
{
struct Packet *pkt;
va_list ap1, ap2;
va_start(ap1, pkttype);
va_start(ap2, pkttype);
pkt = construct_packet(ssh, pkttype, ap1, ap2);
va_end(ap2);
va_end(ap1);
s_wrpkt(ssh, pkt);
ssh_free_packet(pkt);
}
static void defer_packet(Ssh ssh, int pkttype, ...)
{
struct Packet *pkt;
va_list ap1, ap2;
va_start(ap1, pkttype);
va_start(ap2, pkttype);
pkt = construct_packet(ssh, pkttype, ap1, ap2);
va_end(ap2);
va_end(ap1);
s_wrpkt_defer(ssh, pkt);
ssh_free_packet(pkt);
}
static int ssh_versioncmp(char *a, char *b)
{
char *ae, *be;
unsigned long av, bv;
av = strtoul(a, &ae, 10);
bv = strtoul(b, &be, 10);
if (av != bv)
return (av < bv ? -1 : +1);
if (*ae == '.')
ae++;
if (*be == '.')
be++;
av = strtoul(ae, &ae, 10);
bv = strtoul(be, &be, 10);
if (av != bv)
return (av < bv ? -1 : +1);
return 0;
}
/*
* Utility routines for putting an SSH-protocol `string' and
* `uint32' into a SHA state.
*/
#include <stdio.h>
static void sha_string(SHA_State * s, void *str, int len)
{
unsigned char lenblk[4];
PUT_32BIT(lenblk, len);
SHA_Bytes(s, lenblk, 4);
SHA_Bytes(s, str, len);
}
static void sha_uint32(SHA_State * s, unsigned i)
{
unsigned char intblk[4];
PUT_32BIT(intblk, i);
SHA_Bytes(s, intblk, 4);
}
/*
* SSH2 packet construction functions.
*/
static void ssh2_pkt_ensure(struct Packet *pkt, int length)
{
if (pkt->maxlen < length) {
pkt->maxlen = length + 256;
pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
}
}
static void ssh2_pkt_adddata(struct Packet *pkt, void *data, int len)
{
if (pkt->logmode != PKTLOG_EMIT) {
pkt->nblanks++;
pkt->blanks = sresize(pkt->blanks, pkt->nblanks, struct logblank_t);
pkt->blanks[pkt->nblanks-1].offset = pkt->length - 6;
pkt->blanks[pkt->nblanks-1].len = len;
pkt->blanks[pkt->nblanks-1].type = pkt->logmode;
}
pkt->length += len;
ssh2_pkt_ensure(pkt, pkt->length);
memcpy(pkt->data + pkt->length - len, data, len);
}
static void ssh2_pkt_addbyte(struct Packet *pkt, unsigned char byte)
{
ssh2_pkt_adddata(pkt, &byte, 1);
}
static struct Packet *ssh2_pkt_init(int pkt_type)
{
struct Packet *pkt = ssh_new_packet();
pkt->length = 5;
pkt->forcepad = 0;
ssh2_pkt_addbyte(pkt, (unsigned char) pkt_type);
return pkt;
}
static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value)
{
ssh2_pkt_adddata(pkt, &value, 1);
}
static void ssh2_pkt_adduint32(struct Packet *pkt, unsigned long value)
{
unsigned char x[4];
PUT_32BIT(x, value);
ssh2_pkt_adddata(pkt, x, 4);
}
static void ssh2_pkt_addstring_start(struct Packet *pkt)
{
ssh2_pkt_adduint32(pkt, 0);
pkt->savedpos = pkt->length;
}
static void ssh2_pkt_addstring_str(struct Packet *pkt, char *data)
{
ssh2_pkt_adddata(pkt, data, strlen(data));
PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
}
static void ssh2_pkt_addstring_data(struct Packet *pkt, char *data, int len)
{
ssh2_pkt_adddata(pkt, data, len);
PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
}
static void ssh2_pkt_addstring(struct Packet *pkt, char *data)
{
ssh2_pkt_addstring_start(pkt);
ssh2_pkt_addstring_str(pkt, data);
}
static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
{
unsigned char *p;
int i, n = (bignum_bitcount(b) + 7) / 8;
p = snewn(n + 1, unsigned char);
if (!p)
fatalbox("out of memory");
p[0] = 0;
for (i = 1; i <= n; i++)
p[i] = bignum_byte(b, n - i);
i = 0;
while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
i++;
memmove(p, p + i, n + 1 - i);
*len = n + 1 - i;
return p;
}
static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b)
{
unsigned char *p;
int len;
p = ssh2_mpint_fmt(b, &len);
ssh2_pkt_addstring_start(pkt);
ssh2_pkt_addstring_data(pkt, (char *)p, len);
sfree(p);
}
/*
* Construct an SSH2 final-form packet: compress it, encrypt it,
* put the MAC on it. Final packet, ready to be sent, is stored in
* pkt->data. Total length is returned.
*/
static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
{
int cipherblk, maclen, padding, i;
if (ssh->logctx)
log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
ssh2_pkt_type(ssh->pkt_ctx, pkt->data[5]),
pkt->data + 6, pkt->length - 6,
pkt->nblanks, pkt->blanks);
sfree(pkt->blanks); pkt->blanks = NULL;
pkt->nblanks = 0;
/*
* Compress packet payload.
*/
{
unsigned char *newpayload;
int newlen;
if (ssh->cscomp &&
ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5,
pkt->length - 5,
&newpayload, &newlen)) {
pkt->length = 5;
ssh2_pkt_adddata(pkt, newpayload, newlen);
sfree(newpayload);
}
}
/*
* Add padding. At least four bytes, and must also bring total
* length (minus MAC) up to a multiple of the block size.
* If pkt->forcepad is set, make sure the packet is at least that size
* after padding.
*/
cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
padding = 4;
if (pkt->length + padding < pkt->forcepad)
padding = pkt->forcepad - pkt->length;
padding +=
(cipherblk - (pkt->length + padding) % cipherblk) % cipherblk;
assert(padding <= 255);
maclen = ssh->csmac ? ssh->csmac->len : 0;
ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
pkt->data[4] = padding;
for (i = 0; i < padding; i++)
pkt->data[pkt->length + i] = random_byte();
PUT_32BIT(pkt->data, pkt->length + padding - 4);
if (ssh->csmac)
ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
pkt->length + padding,
ssh->v2_outgoing_sequence);
ssh->v2_outgoing_sequence++; /* whether or not we MACed */
if (ssh->cscipher)
ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
pkt->data, pkt->length + padding);
pkt->encrypted_len = pkt->length + padding;
/* Ready-to-send packet starts at pkt->data. We return length. */
return pkt->length + padding + maclen;
}
/*
* Routines called from the main SSH code to send packets. There
* are quite a few of these, because we have two separate
* mechanisms for delaying the sending of packets:
*
* - In order to send an IGNORE message and a password message in
* a single fixed-length blob, we require the ability to
* concatenate the encrypted forms of those two packets _into_ a
* single blob and then pass it to our <network.h> transport
* layer in one go. Hence, there's a deferment mechanism which
* works after packet encryption.
*
* - In order to avoid sending any connection-layer messages
* during repeat key exchange, we have to queue up any such
* outgoing messages _before_ they are encrypted (and in
* particular before they're allocated sequence numbers), and
* then send them once we've finished.
*
* I call these mechanisms `defer' and `queue' respectively, so as
* to distinguish them reasonably easily.
*
* The functions send_noqueue() and defer_noqueue() free the packet
* structure they are passed. Every outgoing packet goes through
* precisely one of these functions in its life; packets passed to
* ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of
* these or get queued, and then when the queue is later emptied
* the packets are all passed to defer_noqueue().
*/
/*
* Send an SSH2 packet immediately, without queuing or deferring.
*/
static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
{
int len;
int backlog;
len = ssh2_pkt_construct(ssh, pkt);
backlog = sk_write(ssh->s, (char *)pkt->data, len);
if (backlog > SSH_MAX_BACKLOG)
ssh_throttle_all(ssh, 1, backlog);
ssh->outgoing_data_size += pkt->encrypted_len;
if (!ssh->kex_in_progress &&
ssh->max_data_size != 0 &&
ssh->outgoing_data_size > ssh->max_data_size)
do_ssh2_transport(ssh, "too much data sent", -1, NULL);
ssh_free_packet(pkt);
}
/*
* Defer an SSH2 packet.
*/
static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt)
{
int len = ssh2_pkt_construct(ssh, pkt);
if (ssh->deferred_len + len > ssh->deferred_size) {
ssh->deferred_size = ssh->deferred_len + len + 128;
ssh->deferred_send_data = sresize(ssh->deferred_send_data,
ssh->deferred_size,
unsigned char);
}
memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->data, len);
ssh->deferred_len += len;
ssh->deferred_data_size += pkt->encrypted_len;
ssh_free_packet(pkt);
}
/*
* Queue an SSH2 packet.
*/
static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt)
{
assert(ssh->queueing);
if (ssh->queuelen >= ssh->queuesize) {
ssh->queuesize = ssh->queuelen + 32;
ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *);
}
ssh->queue[ssh->queuelen++] = pkt;
}
/*
* Either queue or send a packet, depending on whether queueing is
* set.
*/
static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
{
if (ssh->queueing)
ssh2_pkt_queue(ssh, pkt);
else
ssh2_pkt_send_noqueue(ssh, pkt);
}
#if 0 /* disused */
/*
* Either queue or defer a packet, depending on whether queueing is
* set.
*/
static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
{
if (ssh->queueing)
ssh2_pkt_queue(ssh, pkt);
else
ssh2_pkt_defer_noqueue(ssh, pkt);
}
#endif
/*
* Send the whole deferred data block constructed by
* ssh2_pkt_defer() or SSH1's defer_packet().
*
* The expected use of the defer mechanism is that you call
* ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If
* not currently queueing, this simply sets up deferred_send_data
* and then sends it. If we _are_ currently queueing, the calls to
* ssh2_pkt_defer() put the deferred packets on to the queue
* instead, and therefore ssh_pkt_defersend() has no deferred data
* to send. Hence, there's no need to make it conditional on
* ssh->queueing.
*/
static void ssh_pkt_defersend(Ssh ssh)
{
int backlog;
backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
ssh->deferred_len);
ssh->deferred_len = ssh->deferred_size = 0;
sfree(ssh->deferred_send_data);
ssh->deferred_send_data = NULL;
if (backlog > SSH_MAX_BACKLOG)
ssh_throttle_all(ssh, 1, backlog);
ssh->outgoing_data_size += ssh->deferred_data_size;
if (!ssh->kex_in_progress &&
ssh->max_data_size != 0 &&
ssh->outgoing_data_size > ssh->max_data_size)
do_ssh2_transport(ssh, "too much data sent", -1, NULL);
ssh->deferred_data_size = 0;
}
/*
* Send all queued SSH2 packets. We send them by means of
* ssh2_pkt_defer_noqueue(), in case they included a pair of
* packets that needed to be lumped together.
*/
static void ssh2_pkt_queuesend(Ssh ssh)
{
int i;
assert(!ssh->queueing);
for (i = 0; i < ssh->queuelen; i++)
ssh2_pkt_defer_noqueue(ssh, ssh->queue[i]);
ssh->queuelen = 0;
ssh_pkt_defersend(ssh);
}
#if 0
void bndebug(char *string, Bignum b)
{
unsigned char *p;
int i, len;
p = ssh2_mpint_fmt(b, &len);
debug(("%s", string));
for (i = 0; i < len; i++)
debug((" %02x", p[i]));
debug(("\n"));
sfree(p);
}
#endif
static void sha_mpint(SHA_State * s, Bignum b)
{
unsigned char *p;
int len;
p = ssh2_mpint_fmt(b, &len);
sha_string(s, p, len);
sfree(p);
}
/*
* Packet decode functions for both SSH1 and SSH2.
*/
static unsigned long ssh_pkt_getuint32(struct Packet *pkt)
{
unsigned long value;
if (pkt->length - pkt->savedpos < 4)
return 0; /* arrgh, no way to decline (FIXME?) */
value = GET_32BIT(pkt->body + pkt->savedpos);
pkt->savedpos += 4;
return value;
}
static int ssh2_pkt_getbool(struct Packet *pkt)
{
unsigned long value;
if (pkt->length - pkt->savedpos < 1)
return 0; /* arrgh, no way to decline (FIXME?) */
value = pkt->body[pkt->savedpos] != 0;
pkt->savedpos++;
return value;
}
static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length)
{
int len;
*p = NULL;
*length = 0;
if (pkt->length - pkt->savedpos < 4)
return;
len = GET_32BIT(pkt->body + pkt->savedpos);
if (len < 0)
return;
*length = len;
pkt->savedpos += 4;
if (pkt->length - pkt->savedpos < *length)
return;
*p = (char *)(pkt->body + pkt->savedpos);
pkt->savedpos += *length;
}
static void *ssh_pkt_getdata(struct Packet *pkt, int length)
{
if (pkt->length - pkt->savedpos < length)
return NULL;
pkt->savedpos += length;
return pkt->body + (pkt->savedpos - length);
}
static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key,
unsigned char **keystr)
{
int j;
j = makekey(pkt->body + pkt->savedpos,
pkt->length - pkt->savedpos,
key, keystr, 0);
if (j < 0)
return FALSE;
pkt->savedpos += j;
assert(pkt->savedpos < pkt->length);
return TRUE;
}
static Bignum ssh1_pkt_getmp(struct Packet *pkt)
{
int j;
Bignum b;
j = ssh1_read_bignum(pkt->body + pkt->savedpos,
pkt->length - pkt->savedpos, &b);
if (j < 0)
return NULL;
pkt->savedpos += j;
return b;
}
static Bignum ssh2_pkt_getmp(struct Packet *pkt)
{
char *p;
int length;
Bignum b;
ssh_pkt_getstring(pkt, &p, &length);
if (!p)
return NULL;
if (p[0] & 0x80)
return NULL;
b = bignum_from_bytes((unsigned char *)p, length);
return b;
}
/*
* Helper function to add an SSH2 signature blob to a packet.
* Expects to be shown the public key blob as well as the signature
* blob. Normally works just like ssh2_pkt_addstring, but will
* fiddle with the signature packet if necessary for
* BUG_SSH2_RSA_PADDING.
*/
static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt,
void *pkblob_v, int pkblob_len,
void *sigblob_v, int sigblob_len)
{
unsigned char *pkblob = (unsigned char *)pkblob_v;
unsigned char *sigblob = (unsigned char *)sigblob_v;
/* dmemdump(pkblob, pkblob_len); */
/* dmemdump(sigblob, sigblob_len); */
/*
* See if this is in fact an ssh-rsa signature and a buggy
* server; otherwise we can just do this the easy way.
*/
if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
(GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
int pos, len, siglen;
/*
* Find the byte length of the modulus.
*/
pos = 4+7; /* skip over "ssh-rsa" */
pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
len = GET_32BIT(pkblob+pos); /* find length of modulus */
pos += 4; /* find modulus itself */
while (len > 0 && pkblob[pos] == 0)
len--, pos++;
/* debug(("modulus length is %d\n", len)); */
/*
* Now find the signature integer.
*/
pos = 4+7; /* skip over "ssh-rsa" */
siglen = GET_32BIT(sigblob+pos);
/* debug(("signature length is %d\n", siglen)); */
if (len != siglen) {
unsigned char newlen[4];
ssh2_pkt_addstring_start(pkt);
ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos);
/* dmemdump(sigblob, pos); */
pos += 4; /* point to start of actual sig */
PUT_32BIT(newlen, len);
ssh2_pkt_addstring_data(pkt, (char *)newlen, 4);
/* dmemdump(newlen, 4); */
newlen[0] = 0;
while (len-- > siglen) {
ssh2_pkt_addstring_data(pkt, (char *)newlen, 1);
/* dmemdump(newlen, 1); */
}
ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen);
/* dmemdump(sigblob+pos, siglen); */
return;
}
/* Otherwise fall through and do it the easy way. */
}
ssh2_pkt_addstring_start(pkt);
ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len);
}
/*
* Examine the remote side's version string and compare it against
* a list of known buggy implementations.
*/
static void ssh_detect_bugs(Ssh ssh, char *vstring)
{
char *imp; /* pointer to implementation part */
imp = vstring;
imp += strcspn(imp, "-");
if (*imp) imp++;
imp += strcspn(imp, "-");
if (*imp) imp++;
ssh->remote_bugs = 0;
if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
(ssh->cfg.sshbug_ignore1 == AUTO &&
(!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
!strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
!strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
!strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
/*
* These versions don't support SSH1_MSG_IGNORE, so we have
* to use a different defence against password length
* sniffing.
*/
ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
logevent("We believe remote version has SSH1 ignore bug");
}
if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
(ssh->cfg.sshbug_plainpw1 == AUTO &&
(!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
/*
* These versions need a plain password sent; they can't
* handle having a null and a random length of data after
* the password.
*/
ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
logevent("We believe remote version needs a plain SSH1 password");
}
if (ssh->cfg.sshbug_rsa1 == FORCE_ON ||
(ssh->cfg.sshbug_rsa1 == AUTO &&
(!strcmp(imp, "Cisco-1.25")))) {
/*
* These versions apparently have no clue whatever about
* RSA authentication and will panic and die if they see
* an AUTH_RSA message.
*/
ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
logevent("We believe remote version can't handle RSA authentication");
}
if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
(ssh->cfg.sshbug_hmac2 == AUTO &&
!wc_match("* VShell", imp) &&
(wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
wc_match("2.1 *", imp)))) {
/*
* These versions have the HMAC bug.
*/
ssh->remote_bugs |= BUG_SSH2_HMAC;
logevent("We believe remote version has SSH2 HMAC bug");
}
if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
(ssh->cfg.sshbug_derivekey2 == AUTO &&
!wc_match("* VShell", imp) &&
(wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
/*
* These versions have the key-derivation bug (failing to
* include the literal shared secret in the hashes that
* generate the keys).
*/
ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
logevent("We believe remote version has SSH2 key-derivation bug");
}
if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
(ssh->cfg.sshbug_rsapad2 == AUTO &&
(wc_match("OpenSSH_2.[5-9]*", imp) ||
wc_match("OpenSSH_3.[0-2]*", imp)))) {
/*
* These versions have the SSH2 RSA padding bug.
*/
ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
logevent("We believe remote version has SSH2 RSA padding bug");
}
if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
(ssh->cfg.sshbug_pksessid2 == AUTO &&
wc_match("OpenSSH_2.[0-2]*", imp))) {
/*
* These versions have the SSH2 session-ID bug in
* public-key authentication.
*/
ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
logevent("We believe remote version has SSH2 public-key-session-ID bug");
}
if (ssh->cfg.sshbug_rekey2 == FORCE_ON ||
(ssh->cfg.sshbug_rekey2 == AUTO &&
(wc_match("OpenSSH_2.[0-4]*", imp) ||
wc_match("OpenSSH_2.5.[0-3]*", imp) ||
wc_match("Sun_SSH_1.0", imp) ||
wc_match("Sun_SSH_1.0.1", imp)))) {
/*
* These versions have the SSH2 rekey bug.
*/
ssh->remote_bugs |= BUG_SSH2_REKEY;
logevent("We believe remote version has SSH2 rekey bug");
}
}
/*
* The `software version' part of an SSH version string is required
* to contain no spaces or minus signs.
*/
static void ssh_fix_verstring(char *str)
{
/* Eat "SSH-<protoversion>-". */
assert(*str == 'S'); str++;
assert(*str == 'S'); str++;
assert(*str == 'H'); str++;
assert(*str == '-'); str++;
while (*str && *str != '-') str++;
assert(*str == '-'); str++;
/* Convert minus signs and spaces in the remaining string into
* underscores. */
while (*str) {
if (*str == '-' || *str == ' ')
*str = '_';
str++;
}
}
static int do_ssh_init(Ssh ssh, unsigned char c)
{
struct do_ssh_init_state {
int vslen;
char version[10];
char *vstring;
int vstrsize;
int i;
int proto1, proto2;
};
crState(do_ssh_init_state);
crBegin(ssh->do_ssh_init_crstate);
/* Search for the string "SSH-" in the input. */
s->i = 0;
while (1) {
static const int transS[] = { 1, 2, 2, 1 };
static const int transH[] = { 0, 0, 3, 0 };
static const int transminus[] = { 0, 0, 0, -1 };
if (c == 'S')
s->i = transS[s->i];
else if (c == 'H')
s->i = transH[s->i];
else if (c == '-')
s->i = transminus[s->i];
else
s->i = 0;
if (s->i < 0)
break;
crReturn(1); /* get another character */
}
s->vstrsize = 16;
s->vstring = snewn(s->vstrsize, char);
strcpy(s->vstring, "SSH-");
s->vslen = 4;
s->i = 0;
while (1) {
crReturn(1); /* get another char */
if (s->vslen >= s->vstrsize - 1) {
s->vstrsize += 16;
s->vstring = sresize(s->vstring, s->vstrsize, char);
}
s->vstring[s->vslen++] = c;
if (s->i >= 0) {
if (c == '-') {
s->version[s->i] = '\0';
s->i = -1;
} else if (s->i < sizeof(s->version) - 1)
s->version[s->i++] = c;
} else if (c == '\012')
break;
}
ssh->agentfwd_enabled = FALSE;
ssh->rdpkt2_state.incoming_sequence = 0;
s->vstring[s->vslen] = 0;
s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
logeventf(ssh, "Server version: %s", s->vstring);
ssh_detect_bugs(ssh, s->vstring);
/*
* Decide which SSH protocol version to support.
*/
/* Anything strictly below "2.0" means protocol 1 is supported. */
s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
/* Anything greater or equal to "1.99" means protocol 2 is supported. */
s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
if (ssh->cfg.sshprot == 0 && !s->proto1) {
bombout(("SSH protocol version 1 required by user but not provided by server"));
crStop(0);
}
if (ssh->cfg.sshprot == 3 && !s->proto2) {
bombout(("SSH protocol version 2 required by user but not provided by server"));
crStop(0);
}
{
char *verstring;
if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
/*
* Construct a v2 version string.
*/
verstring = dupprintf("SSH-2.0-%s\015\012", sshver);
ssh->version = 2;
} else {
/*
* Construct a v1 version string.
*/
verstring = dupprintf("SSH-%s-%s\012",
(ssh_versioncmp(s->version, "1.5") <= 0 ?
s->version : "1.5"),
sshver);
ssh->version = 1;
}
ssh_fix_verstring(verstring);
if (ssh->version == 2) {
/*
* Hash our version string and their version string.
*/
SHA_Init(&ssh->exhashbase);
sha_string(&ssh->exhashbase, verstring,
strcspn(verstring, "\015\012"));
sha_string(&ssh->exhashbase, s->vstring,
strcspn(s->vstring, "\015\012"));
/*
* Initialise SSHv2 protocol.
*/
ssh->protocol = ssh2_protocol;
ssh2_protocol_setup(ssh);
ssh->s_rdpkt = ssh2_rdpkt;
} else {
/*
* Initialise SSHv1 protocol.
*/
ssh->protocol = ssh1_protocol;
ssh1_protocol_setup(ssh);
ssh->s_rdpkt = ssh1_rdpkt;
}
logeventf(ssh, "We claim version: %.*s",
strcspn(verstring, "\015\012"), verstring);
sk_write(ssh->s, verstring, strlen(verstring));
sfree(verstring);
}
logeventf(ssh, "Using SSH protocol version %d", ssh->version);
update_specials_menu(ssh->frontend);
ssh->state = SSH_STATE_BEFORE_SIZE;
ssh->pinger = pinger_new(&ssh->cfg, &ssh_backend, ssh);
sfree(s->vstring);
crFinish(0);
}
static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
{
crBegin(ssh->ssh_gotdata_crstate);
/*
* To begin with, feed the characters one by one to the
* protocol initialisation / selection function do_ssh_init().
* When that returns 0, we're done with the initial greeting
* exchange and can move on to packet discipline.
*/
while (1) {
int ret; /* need not be kept across crReturn */
if (datalen == 0)
crReturnV; /* more data please */
ret = do_ssh_init(ssh, *data);
data++;
datalen--;
if (ret == 0)
break;
}
/*
* We emerge from that loop when the initial negotiation is
* over and we have selected an s_rdpkt function. Now pass
* everything to s_rdpkt, and then pass the resulting packets
* to the proper protocol handler.
*/
if (datalen == 0)
crReturnV;
while (1) {
while (datalen > 0) {
struct Packet *pktin = ssh->s_rdpkt(ssh, &data, &datalen);
if (pktin) {
ssh->protocol(ssh, NULL, 0, pktin);
ssh_free_packet(pktin);
}
if (ssh->state == SSH_STATE_CLOSED)
return;
}
crReturnV;
}
crFinishV;
}
static int ssh_do_close(Ssh ssh, int notify_exit)
{
int i, ret = 0;
struct ssh_channel *c;
ssh->state = SSH_STATE_CLOSED;
if (ssh->s) {
sk_close(ssh->s);
ssh->s = NULL;
if (notify_exit)
notify_remote_exit(ssh->frontend);
else
ret = 1;
}
/*
* Now we must shut down any port and X forwardings going
* through this connection.
*/
if (ssh->channels) {
for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
switch (c->type) {
case CHAN_X11:
x11_close(c->u.x11.s);
break;
case CHAN_SOCKDATA:
pfd_close(c->u.pfd.s);
break;
}
del234(ssh->channels, c);
if (ssh->version == 2)
bufchain_clear(&c->v.v2.outbuffer);
sfree(c);
}
}
return ret;
}
static void ssh_log(Plug plug, int type, SockAddr addr, int port,
const char *error_msg, int error_code)
{
Ssh ssh = (Ssh) plug;
char addrbuf[256], *msg;
sk_getaddr(addr, addrbuf, lenof(addrbuf));
if (type == 0)
msg = dupprintf("Connecting to %s port %d", addrbuf, port);
else
msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
logevent(msg);
sfree(msg);
}
static int ssh_closing(Plug plug, const char *error_msg, int error_code,
int calling_back)
{
Ssh ssh = (Ssh) plug;
int need_notify = ssh_do_close(ssh, FALSE);
if (!error_msg && !ssh->close_expected) {
error_msg = "Server unexpectedly closed network connection";
}
if (error_msg) {
/* A socket error has occurred. */
logevent(error_msg);
connection_fatal(ssh->frontend, "%s", error_msg);
} else {
logevent("Server closed network connection");
}
if (need_notify)
notify_remote_exit(ssh->frontend);
return 0;
}
static int ssh_receive(Plug plug, int urgent, char *data, int len)
{
Ssh ssh = (Ssh) plug;
ssh_gotdata(ssh, (unsigned char *)data, len);
if (ssh->state == SSH_STATE_CLOSED) {
ssh_do_close(ssh, TRUE);
return 0;
}
return 1;
}
static void ssh_sent(Plug plug, int bufsize)
{
Ssh ssh = (Ssh) plug;
/*
* If the send backlog on the SSH socket itself clears, we
* should unthrottle the whole world if it was throttled.
*/
if (bufsize < SSH_MAX_BACKLOG)
ssh_throttle_all(ssh, 0, bufsize);
}
/*
* Connect to specified host and port.
* Returns an error message, or NULL on success.
* Also places the canonical host name into `realhost'. It must be
* freed by the caller.
*/
static const char *connect_to_host(Ssh ssh, char *host, int port,
char **realhost, int nodelay, int keepalive)
{
static const struct plug_function_table fn_table = {
ssh_log,
ssh_closing,
ssh_receive,
ssh_sent,
NULL
};
SockAddr addr;
const char *err;
ssh->savedhost = snewn(1 + strlen(host), char);
if (!ssh->savedhost)
fatalbox("Out of memory");
strcpy(ssh->savedhost, host);
if (port < 0)
port = 22; /* default ssh port */
ssh->savedport = port;
/*
* Try to find host.
*/
logeventf(ssh, "Looking up host \"%s\"%s", host,
(ssh->cfg.addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
(ssh->cfg.addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" : "")));
addr = name_lookup(host, port, realhost, &ssh->cfg,
ssh->cfg.addressfamily);
if ((err = sk_addr_error(addr)) != NULL) {
sk_addr_free(addr);
return err;
}
/*
* Open socket.
*/
ssh->fn = &fn_table;
ssh->s = new_connection(addr, *realhost, port,
0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg);
if ((err = sk_socket_error(ssh->s)) != NULL) {
ssh->s = NULL;
notify_remote_exit(ssh->frontend);
return err;
}
return NULL;
}
/*
* Throttle or unthrottle the SSH connection.
*/
static void ssh1_throttle(Ssh ssh, int adjust)
{
int old_count = ssh->v1_throttle_count;
ssh->v1_throttle_count += adjust;
assert(ssh->v1_throttle_count >= 0);
if (ssh->v1_throttle_count && !old_count) {
sk_set_frozen(ssh->s, 1);
} else if (!ssh->v1_throttle_count && old_count) {
sk_set_frozen(ssh->s, 0);
}
}
/*
* Throttle or unthrottle _all_ local data streams (for when sends
* on the SSH connection itself back up).
*/
static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
{
int i;
struct ssh_channel *c;
if (enable == ssh->throttled_all)
return;
ssh->throttled_all = enable;
ssh->overall_bufsize = bufsize;
if (!ssh->channels)
return;
for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
switch (c->type) {
case CHAN_MAINSESSION:
/*
* This is treated separately, outside the switch.
*/
break;
case CHAN_X11:
x11_override_throttle(c->u.x11.s, enable);
break;
case CHAN_AGENT:
/* Agent channels require no buffer management. */
break;
case CHAN_SOCKDATA:
pfd_override_throttle(c->u.pfd.s, enable);
break;
}
}
}
/*
* Username and password input, abstracted off into routines
* reusable in several places - even between SSH1 and SSH2.
*/
/* Set up a username or password input loop on a given buffer. */
static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
{
ssh->userpass_input_buffer = buffer;
ssh->userpass_input_buflen = buflen;
ssh->userpass_input_bufpos = 0;
ssh->userpass_input_echo = echo;
}
/*
* Process some terminal data in the course of username/password
* input. Returns >0 for success (line of input returned in
* buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
* for inconclusive (keep waiting for more input please).
*/
static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
{
char c;
while (inlen--) {
switch (c = *in++) {
case 10:
case 13:
ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
return +1;
break;
case 8:
case 127:
if (ssh->userpass_input_bufpos > 0) {
if (ssh->userpass_input_echo)
c_write_str(ssh, "\b \b");
ssh->userpass_input_bufpos--;
}
break;
case 21:
case 27:
while (ssh->userpass_input_bufpos > 0) {
if (ssh->userpass_input_echo)
c_write_str(ssh, "\b \b");
ssh->userpass_input_bufpos--;
}
break;
case 3:
case 4:
return -1;
break;
default:
/*
* This simplistic check for printability is disabled
* when we're doing password input, because some people
* have control characters in their passwords.o
*/
if ((!ssh->userpass_input_echo ||
(c >= ' ' && c <= '~') ||
((unsigned char) c >= 160))
&& ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
if (ssh->userpass_input_echo)
c_write(ssh, &c, 1);
}
break;
}
}
return 0;
}
static void ssh_agent_callback(void *sshv, void *reply, int replylen)
{
Ssh ssh = (Ssh) sshv;
ssh->agent_response = reply;
ssh->agent_response_len = replylen;
if (ssh->version == 1)
do_ssh1_login(ssh, NULL, -1, NULL);
else
do_ssh2_authconn(ssh, NULL, -1, NULL);
}
static void ssh_agentf_callback(void *cv, void *reply, int replylen)
{
struct ssh_channel *c = (struct ssh_channel *)cv;
Ssh ssh = c->ssh;
void *sentreply = reply;
if (!sentreply) {
/* Fake SSH_AGENT_FAILURE. */
sentreply = "\0\0\0\1\5";
replylen = 5;
}
if (ssh->version == 2) {
ssh2_add_channel_data(c, sentreply, replylen);
ssh2_try_send(c);
} else {
send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
PKT_INT, c->remoteid,
PKTT_DATA,
PKT_INT, replylen,
PKT_DATA, sentreply, replylen,
PKTT_OTHER,
PKT_END);
}
if (reply)
sfree(reply);
}
/*
* Handle the key exchange and user authentication phases.
*/
static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
struct Packet *pktin)
{
int i, j, ret;
unsigned char cookie[8], *ptr;
struct RSAKey servkey, hostkey;
struct MD5Context md5c;
struct do_ssh1_login_state {
int len;
unsigned char *rsabuf, *keystr1, *keystr2;
unsigned long supported_ciphers_mask, supported_auths_mask;
int tried_publickey, tried_agent;
int tis_auth_refused, ccard_auth_refused;
unsigned char session_id[16];
int cipher_type;
char username[100];
void *publickey_blob;
int publickey_bloblen;
char password[100];
char prompt[200];
int pos;
char c;
int pwpkt_type;
unsigned char request[5], *response, *p;
int responselen;
int keyi, nkeys;
int authed;
struct RSAKey key;
Bignum challenge;
char *commentp;
int commentlen;
};
crState(do_ssh1_login_state);
crBegin(ssh->do_ssh1_login_crstate);
if (!pktin)
crWaitUntil(pktin);
if (pktin->type != SSH1_SMSG_PUBLIC_KEY) {
bombout(("Public key packet not received"));
crStop(0);
}
logevent("Received public keys");
ptr = ssh_pkt_getdata(pktin, 8);
if (!ptr) {
bombout(("SSH1 public key packet stopped before random cookie"));
crStop(0);
}
memcpy(cookie, ptr, 8);
if (!ssh1_pkt_getrsakey(pktin, &servkey, &s->keystr1) ||
!ssh1_pkt_getrsakey(pktin, &hostkey, &s->keystr2)) {
bombout(("Failed to read SSH1 public keys from public key packet"));
crStop(0);
}
/*
* Log the host key fingerprint.
*/
{
char logmsg[80];
logevent("Host key fingerprint is:");
strcpy(logmsg, " ");
hostkey.comment = NULL;
rsa_fingerprint(logmsg + strlen(logmsg),
sizeof(logmsg) - strlen(logmsg), &hostkey);
logevent(logmsg);
}
ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
s->supported_auths_mask = ssh_pkt_getuint32(pktin);
ssh->v1_local_protoflags =
ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
MD5Init(&md5c);
MD5Update(&md5c, s->keystr2, hostkey.bytes);
MD5Update(&md5c, s->keystr1, servkey.bytes);
MD5Update(&md5c, cookie, 8);
MD5Final(s->session_id, &md5c);
for (i = 0; i < 32; i++)
ssh->session_key[i] = random_byte();
/*
* Verify that the `bits' and `bytes' parameters match.
*/
if (hostkey.bits > hostkey.bytes * 8 ||
servkey.bits > servkey.bytes * 8) {
bombout(("SSH1 public keys were badly formatted"));
crStop(0);
}
s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
s->rsabuf = snewn(s->len, unsigned char);
if (!s->rsabuf)
fatalbox("Out of memory");
/*
* Verify the host key.
*/
{
/*
* First format the key into a string.
*/
int len = rsastr_len(&hostkey);
char fingerprint[100];
char *keystr = snewn(len, char);
if (!keystr)
fatalbox("Out of memory");
rsastr_fmt(keystr, &hostkey);
rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
verify_ssh_host_key(ssh->frontend,
ssh->savedhost, ssh->savedport, "rsa", keystr,
fingerprint);
sfree(keystr);
}
for (i = 0; i < 32; i++) {
s->rsabuf[i] = ssh->session_key[i];
if (i < 16)
s->rsabuf[i] ^= s->session_id[i];
}
if (hostkey.bytes > servkey.bytes) {
ret = rsaencrypt(s->rsabuf, 32, &servkey);
if (ret)
ret = rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
} else {
ret = rsaencrypt(s->rsabuf, 32, &hostkey);
if (ret)
ret = rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
}
if (!ret) {
bombout(("SSH1 public key encryptions failed due to bad formatting"));
crStop(0);
}
logevent("Encrypted session key");
{
int cipher_chosen = 0, warn = 0;
char *cipher_string = NULL;
int i;
for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
int next_cipher = ssh->cfg.ssh_cipherlist[i];
if (next_cipher == CIPHER_WARN) {
/* If/when we choose a cipher, warn about it */
warn = 1;
} else if (next_cipher == CIPHER_AES) {
/* XXX Probably don't need to mention this. */
logevent("AES not supported in SSH1, skipping");
} else {
switch (next_cipher) {
case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
cipher_string = "3DES"; break;
case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
cipher_string = "Blowfish"; break;
case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
cipher_string = "single-DES"; break;
}
if (s->supported_ciphers_mask & (1 << s->cipher_type))
cipher_chosen = 1;
}
}
if (!cipher_chosen) {
if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
bombout(("Server violates SSH 1 protocol by not "
"supporting 3DES encryption"));
else
/* shouldn't happen */
bombout(("No supported ciphers found"));
crStop(0);
}
/* Warn about chosen cipher if necessary. */
if (warn) {
sk_set_frozen(ssh->s, 1);
askalg(ssh->frontend, "cipher", cipher_string);
sk_set_frozen(ssh->s, 0);
}
}
switch (s->cipher_type) {
case SSH_CIPHER_3DES:
logevent("Using 3DES encryption");
break;
case SSH_CIPHER_DES:
logevent("Using single-DES encryption");
break;
case SSH_CIPHER_BLOWFISH:
logevent("Using Blowfish encryption");
break;
}
send_packet(ssh, SSH1_CMSG_SESSION_KEY,
PKT_CHAR, s->cipher_type,
PKT_DATA, cookie, 8,
PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
PKT_DATA, s->rsabuf, s->len,
PKT_INT, ssh->v1_local_protoflags, PKT_END);
logevent("Trying to enable encryption...");
sfree(s->rsabuf);
ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
&ssh_3des);
ssh->v1_cipher_ctx = ssh->cipher->make_context();
ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
ssh->crcda_ctx = crcda_make_context();
logevent("Installing CRC compensation attack detector");
if (servkey.modulus) {
sfree(servkey.modulus);
servkey.modulus = NULL;
}
if (servkey.exponent) {
sfree(servkey.exponent);
servkey.exponent = NULL;
}
if (hostkey.modulus) {
sfree(hostkey.modulus);
hostkey.modulus = NULL;
}
if (hostkey.exponent) {
sfree(hostkey.exponent);
hostkey.exponent = NULL;
}
crWaitUntil(pktin);
if (pktin->type != SSH1_SMSG_SUCCESS) {
bombout(("Encryption not successfully enabled"));
crStop(0);
}
logevent("Successfully started encryption");
fflush(stdout);
{
if (!*ssh->cfg.username) {
if (ssh_get_line && !ssh_getline_pw_only) {
if (!ssh_get_line("login as: ",
s->username, sizeof(s->username), FALSE)) {
/*
* get_line failed to get a username.
* Terminate.
*/
logevent("No username provided. Abandoning session.");
ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStop(1);
}
} else {
int ret; /* need not be kept over crReturn */
c_write_str(ssh, "login as: ");
ssh->send_ok = 1;
setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
do {
crWaitUntil(!pktin);
ret = process_userpass_input(ssh, in, inlen);
} while (ret == 0);
if (ret < 0)
cleanup_exit(0);
c_write_str(ssh, "\r\n");
}
} else {
strncpy(s->username, ssh->cfg.username, sizeof(s->username));
s->username[sizeof(s->username)-1] = '\0';
}
send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
{
char userlog[22 + sizeof(s->username)];
sprintf(userlog, "Sent username \"%s\"", s->username);
logevent(userlog);
if (flags & FLAG_INTERACTIVE &&
(!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
strcat(userlog, "\r\n");
c_write_str(ssh, userlog);
}
}
}
crWaitUntil(pktin);
if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
/* We must not attempt PK auth. Pretend we've already tried it. */
s->tried_publickey = s->tried_agent = 1;
} else {
s->tried_publickey = s->tried_agent = 0;
}
s->tis_auth_refused = s->ccard_auth_refused = 0;
/* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
if (!filename_is_null(ssh->cfg.keyfile)) {
if (!rsakey_pubblob(&ssh->cfg.keyfile,
&s->publickey_blob, &s->publickey_bloblen, NULL))
s->publickey_blob = NULL;
} else
s->publickey_blob = NULL;
while (pktin->type == SSH1_SMSG_FAILURE) {
s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
if (agent_exists() && !s->tried_agent) {
/*
* Attempt RSA authentication using Pageant.
*/
void *r;
s->authed = FALSE;
s->tried_agent = 1;
logevent("Pageant is running. Requesting keys.");
/* Request the keys held by the agent. */
PUT_32BIT(s->request, 1);
s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
if (!agent_query(s->request, 5, &r, &s->responselen,
ssh_agent_callback, ssh)) {
do {
crReturn(0);
if (pktin) {
bombout(("Unexpected data from server while waiting"
" for agent response"));
crStop(0);
}
} while (pktin || inlen > 0);
r = ssh->agent_response;
s->responselen = ssh->agent_response_len;
}
s->response = (unsigned char *) r;
if (s->response && s->responselen >= 5 &&
s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
s->p = s->response + 5;
s->nkeys = GET_32BIT(s->p);
s->p += 4;
logeventf(ssh, "Pageant has %d SSH1 keys", s->nkeys);
for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
logeventf(ssh, "Trying Pageant key #%d", s->keyi);
if (s->publickey_blob &&
!memcmp(s->p, s->publickey_blob,
s->publickey_bloblen)) {
logevent("This key matches configured key file");
s->tried_publickey = 1;
}
s->p += 4;
{
int n, ok = FALSE;
do { /* do while (0) to make breaking easy */
n = ssh1_read_bignum
(s->p, s->responselen-(s->p-s->response),
&s->key.exponent);
if (n < 0)
break;
s->p += n;
n = ssh1_read_bignum
(s->p, s->responselen-(s->p-s->response),
&s->key.modulus);
if (n < 0)
break;
s->p += n;
if (s->responselen - (s->p-s->response) < 4)
break;
s->commentlen = GET_32BIT(s->p);
s->p += 4;
if (s->responselen - (s->p-s->response) <
s->commentlen)
break;
s->commentp = (char *)s->p;
s->p += s->commentlen;
ok = TRUE;
} while (0);
if (!ok) {
logevent("Pageant key list packet was truncated");
break;
}
}
send_packet(ssh, SSH1_CMSG_AUTH_RSA,
PKT_BIGNUM, s->key.modulus, PKT_END);
crWaitUntil(pktin);
if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
logevent("Key refused");
continue;
}
logevent("Received RSA challenge");
if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) {
bombout(("Server's RSA challenge was badly formatted"));
crStop(0);
}
{
char *agentreq, *q, *ret;
void *vret;
int len, retlen;
len = 1 + 4; /* message type, bit count */
len += ssh1_bignum_length(s->key.exponent);
len += ssh1_bignum_length(s->key.modulus);
len += ssh1_bignum_length(s->challenge);
len += 16; /* session id */
len += 4; /* response format */
agentreq = snewn(4 + len, char);
PUT_32BIT(agentreq, len);
q = agentreq + 4;
*q++ = SSH1_AGENTC_RSA_CHALLENGE;
PUT_32BIT(q, bignum_bitcount(s->key.modulus));
q += 4;
q += ssh1_write_bignum(q, s->key.exponent);
q += ssh1_write_bignum(q, s->key.modulus);
q += ssh1_write_bignum(q, s->challenge);
memcpy(q, s->session_id, 16);
q += 16;
PUT_32BIT(q, 1); /* response format */
if (!agent_query(agentreq, len + 4, &vret, &retlen,
ssh_agent_callback, ssh)) {
sfree(agentreq);
do {
crReturn(0);
if (pktin) {
bombout(("Unexpected data from server"
" while waiting for agent"
" response"));
crStop(0);
}
} while (pktin || inlen > 0);
vret = ssh->agent_response;
retlen = ssh->agent_response_len;
} else
sfree(agentreq);
ret = vret;
if (ret) {
if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
logevent("Sending Pageant's response");
send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
PKT_DATA, ret + 5, 16,
PKT_END);
sfree(ret);
crWaitUntil(pktin);
if (pktin->type == SSH1_SMSG_SUCCESS) {
logevent
("Pageant's response accepted");
if (flags & FLAG_VERBOSE) {
c_write_str(ssh, "Authenticated using"
" RSA key \"");
c_write(ssh, s->commentp,
s->commentlen);
c_write_str(ssh, "\" from agent\r\n");
}
s->authed = TRUE;
} else
logevent
("Pageant's response not accepted");
} else {
logevent
("Pageant failed to answer challenge");
sfree(ret);
}
} else {
logevent("No reply received from Pageant");
}
}
freebn(s->key.exponent);
freebn(s->key.modulus);
freebn(s->challenge);
if (s->authed)
break;
}
sfree(s->response);
}
if (s->authed)
break;
}
if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
if (ssh->cfg.try_tis_auth &&
(s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
!s->tis_auth_refused) {
s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
logevent("Requested TIS authentication");
send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
crWaitUntil(pktin);
if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
logevent("TIS authentication declined");
if (flags & FLAG_INTERACTIVE)
c_write_str(ssh, "TIS authentication refused.\r\n");
s->tis_auth_refused = 1;
continue;
} else {
char *challenge;
int challengelen;
ssh_pkt_getstring(pktin, &challenge, &challengelen);
if (!challenge) {
bombout(("TIS challenge packet was badly formed"));
crStop(0);
}
logevent("Received TIS challenge");
if (challengelen > sizeof(s->prompt) - 1)
challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
memcpy(s->prompt, challenge, challengelen);
/* Prompt heuristic comes from OpenSSH */
strncpy(s->prompt + challengelen,
memchr(s->prompt, '\n', challengelen) ?
"": "\r\nResponse: ",
(sizeof s->prompt) - challengelen);
s->prompt[(sizeof s->prompt) - 1] = '\0';
}
}
if (ssh->cfg.try_tis_auth &&
(s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
!s->ccard_auth_refused) {
s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
logevent("Requested CryptoCard authentication");
send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
crWaitUntil(pktin);
if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
logevent("CryptoCard authentication declined");
c_write_str(ssh, "CryptoCard authentication refused.\r\n");
s->ccard_auth_refused = 1;
continue;
} else {
char *challenge;
int challengelen;
ssh_pkt_getstring(pktin, &challenge, &challengelen);
if (!challenge) {
bombout(("CryptoCard challenge packet was badly formed"));
crStop(0);
}
logevent("Received CryptoCard challenge");
if (challengelen > sizeof(s->prompt) - 1)
challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
memcpy(s->prompt, challenge, challengelen);
strncpy(s->prompt + challengelen,
memchr(s->prompt, '\n', challengelen) ?
"" : "\r\nResponse: ",
sizeof(s->prompt) - challengelen);
s->prompt[sizeof(s->prompt) - 1] = '\0';
}
}
if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
sprintf(s->prompt, "%.90s@%.90s's password: ",
s->username, ssh->savedhost);
}
if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
char *comment = NULL;
int type;
if (flags & FLAG_VERBOSE)
c_write_str(ssh, "Trying public key authentication.\r\n");
logeventf(ssh, "Trying public key \"%s\"",
filename_to_str(&ssh->cfg.keyfile));
type = key_type(&ssh->cfg.keyfile);
if (type != SSH_KEYTYPE_SSH1) {
char *msg = dupprintf("Key is of wrong type (%s)",
key_type_to_str(type));
logevent(msg);
c_write_str(ssh, msg);
c_write_str(ssh, "\r\n");
sfree(msg);
s->tried_publickey = 1;
continue;
}
if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
if (flags & FLAG_VERBOSE)
c_write_str(ssh, "No passphrase required.\r\n");
goto tryauth;
}
sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
sfree(comment);
}
/*
* Show password prompt, having first obtained it via a TIS
* or CryptoCard exchange if we're doing TIS or CryptoCard
* authentication.
*/
if (ssh_get_line) {
if (!ssh_get_line(s->prompt, s->password,
sizeof(s->password), TRUE)) {
/*
* get_line failed to get a password (for example
* because one was supplied on the command line
* which has already failed to work). Terminate.
*/
send_packet(ssh, SSH1_MSG_DISCONNECT,
PKT_STR, "No more passwords available to try",
PKT_END);
logevent("Unable to authenticate");
connection_fatal(ssh->frontend, "Unable to authenticate");
ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStop(1);
}
} else {
/* Prompt may have come from server. We've munged it a bit, so
* we know it to be zero-terminated at least once. */
int ret; /* need not be saved over crReturn */
c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
s->pos = 0;
setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
do {
crWaitUntil(!pktin);
ret = process_userpass_input(ssh, in, inlen);
} while (ret == 0);
if (ret < 0)
cleanup_exit(0);
c_write_str(ssh, "\r\n");
}
tryauth:
if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
/*
* Try public key authentication with the specified
* key file.
*/
s->tried_publickey = 1;
{
const char *error = NULL;
int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
&error);
if (ret == 0) {
c_write_str(ssh, "Couldn't load private key from ");
c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
c_write_str(ssh, " (");
c_write_str(ssh, error);
c_write_str(ssh, ").\r\n");
continue; /* go and try password */
}
if (ret == -1) {
c_write_str(ssh, "Wrong passphrase.\r\n");
s->tried_publickey = 0;
continue; /* try again */
}
}
/*
* Send a public key attempt.
*/
send_packet(ssh, SSH1_CMSG_AUTH_RSA,
PKT_BIGNUM, s->key.modulus, PKT_END);
crWaitUntil(pktin);
if (pktin->type == SSH1_SMSG_FAILURE) {
c_write_str(ssh, "Server refused our public key.\r\n");
continue; /* go and try password */
}
if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
bombout(("Bizarre response to offer of public key"));
crStop(0);
}
{
int i;
unsigned char buffer[32];
Bignum challenge, response;
if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
bombout(("Server's RSA challenge was badly formatted"));
crStop(0);
}
response = rsadecrypt(challenge, &s->key);
freebn(s->key.private_exponent);/* burn the evidence */
for (i = 0; i < 32; i++) {
buffer[i] = bignum_byte(response, 31 - i);
}
MD5Init(&md5c);
MD5Update(&md5c, buffer, 32);
MD5Update(&md5c, s->session_id, 16);
MD5Final(buffer, &md5c);
send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
PKT_DATA, buffer, 16, PKT_END);
freebn(challenge);
freebn(response);
}
crWaitUntil(pktin);
if (pktin->type == SSH1_SMSG_FAILURE) {
if (flags & FLAG_VERBOSE)
c_write_str(ssh, "Failed to authenticate with"
" our public key.\r\n");
continue; /* go and try password */
} else if (pktin->type != SSH1_SMSG_SUCCESS) {
bombout(("Bizarre response to RSA authentication response"));
crStop(0);
}
break; /* we're through! */
} else {
if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
/*
* Defence against traffic analysis: we send a
* whole bunch of packets containing strings of
* different lengths. One of these strings is the
* password, in a SSH1_CMSG_AUTH_PASSWORD packet.
* The others are all random data in
* SSH1_MSG_IGNORE packets. This way a passive
* listener can't tell which is the password, and
* hence can't deduce the password length.
*
* Anybody with a password length greater than 16
* bytes is going to have enough entropy in their
* password that a listener won't find it _that_
* much help to know how long it is. So what we'll
* do is:
*
* - if password length < 16, we send 15 packets
* containing string lengths 1 through 15
*
* - otherwise, we let N be the nearest multiple
* of 8 below the password length, and send 8
* packets containing string lengths N through
* N+7. This won't obscure the order of
* magnitude of the password length, but it will
* introduce a bit of extra uncertainty.
*
* A few servers (the old 1.2.18 through 1.2.22)
* can't deal with SSH1_MSG_IGNORE. For these
* servers, we need an alternative defence. We make
* use of the fact that the password is interpreted
* as a C string: so we can append a NUL, then some
* random data.
*
* One server (a Cisco one) can deal with neither
* SSH1_MSG_IGNORE _nor_ a padded password string.
* For this server we are left with no defences
* against password length sniffing.
*/
if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
/*
* The server can deal with SSH1_MSG_IGNORE, so
* we can use the primary defence.
*/
int bottom, top, pwlen, i;
char *randomstr;
pwlen = strlen(s->password);
if (pwlen < 16) {
bottom = 0; /* zero length passwords are OK! :-) */
top = 15;
} else {
bottom = pwlen & ~7;
top = bottom + 7;
}
assert(pwlen >= bottom && pwlen <= top);
randomstr = snewn(top + 1, char);
for (i = bottom; i <= top; i++) {
if (i == pwlen) {
defer_packet(ssh, s->pwpkt_type,
PKTT_PASSWORD, PKT_STR, s->password,
PKTT_OTHER, PKT_END);
} else {
for (j = 0; j < i; j++) {
do {
randomstr[j] = random_byte();
} while (randomstr[j] == '\0');
}
randomstr[i] = '\0';
defer_packet(ssh, SSH1_MSG_IGNORE,
PKT_STR, randomstr, PKT_END);
}
}
logevent("Sending password with camouflage packets");
ssh_pkt_defersend(ssh);
sfree(randomstr);
}
else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
/*
* The server can't deal with SSH1_MSG_IGNORE
* but can deal with padded passwords, so we
* can use the secondary defence.
*/
char string[64];
char *ss;
int len;
len = strlen(s->password);
if (len < sizeof(string)) {
ss = string;
strcpy(string, s->password);
len++; /* cover the zero byte */
while (len < sizeof(string)) {
string[len++] = (char) random_byte();
}
} else {
ss = s->password;
}
logevent("Sending length-padded password");
send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
PKT_INT, len, PKT_DATA, ss, len,
PKTT_OTHER, PKT_END);
} else {
/*
* The server has _both_
* BUG_CHOKES_ON_SSH1_IGNORE and
* BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
* therefore nothing we can do.
*/
int len;
len = strlen(s->password);
logevent("Sending unpadded password");
send_packet(ssh, s->pwpkt_type,
PKTT_PASSWORD, PKT_INT, len,
PKT_DATA, s->password, len,
PKTT_OTHER, PKT_END);
}
} else {
send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
PKT_STR, s->password, PKTT_OTHER, PKT_END);
}
}
logevent("Sent password");
memset(s->password, 0, strlen(s->password));
crWaitUntil(pktin);
if (pktin->type == SSH1_SMSG_FAILURE) {
if (flags & FLAG_VERBOSE)
c_write_str(ssh, "Access denied\r\n");
logevent("Authentication refused");
} else if (pktin->type != SSH1_SMSG_SUCCESS) {
bombout(("Strange packet received, type %d", pktin->type));
crStop(0);
}
}
logevent("Authentication successful");
crFinish(1);
}
void sshfwd_close(struct ssh_channel *c)
{
Ssh ssh = c->ssh;
if (ssh->state != SSH_STATE_SESSION) {
assert(ssh->state == SSH_STATE_CLOSED);
return;
}
if (c && !c->closes) {
/*
* If halfopen is true, we have sent
* CHANNEL_OPEN for this channel, but it hasn't even been
* acknowledged by the server. So we must set a close flag
* on it now, and then when the server acks the channel
* open, we can close it then.
*/
if (!c->halfopen) {
if (ssh->version == 1) {
send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
PKT_END);
} else {
struct Packet *pktout;
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_send(ssh, pktout);
}
}
c->closes = 1; /* sent MSG_CLOSE */
if (c->type == CHAN_X11) {
c->u.x11.s = NULL;
logevent("Forwarded X11 connection terminated");
} else if (c->type == CHAN_SOCKDATA ||
c->type == CHAN_SOCKDATA_DORMANT) {
c->u.pfd.s = NULL;
logevent("Forwarded port closed");
}
}
}
int sshfwd_write(struct ssh_channel *c, char *buf, int len)
{
Ssh ssh = c->ssh;
if (ssh->state != SSH_STATE_SESSION) {
assert(ssh->state == SSH_STATE_CLOSED);
return 0;
}
if (ssh->version == 1) {
send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
PKT_INT, c->remoteid,
PKTT_DATA,
PKT_INT, len, PKT_DATA, buf, len,
PKTT_OTHER, PKT_END);
/*
* In SSH1 we can return 0 here - implying that forwarded
* connections are never individually throttled - because
* the only circumstance that can cause throttling will be
* the whole SSH connection backing up, in which case
* _everything_ will be throttled as a whole.
*/
return 0;
} else {
ssh2_add_channel_data(c, buf, len);
return ssh2_try_send(c);
}
}
void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
{
Ssh ssh = c->ssh;
if (ssh->state != SSH_STATE_SESSION) {
assert(ssh->state == SSH_STATE_CLOSED);
return;
}
if (ssh->version == 1) {
if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
c->v.v1.throttling = 0;
ssh1_throttle(ssh, -1);
}
} else {
ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
}
}
static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin)
{
struct queued_handler *qh = ssh->qhead;
assert(qh != NULL);
assert(pktin->type == qh->msg1 || pktin->type == qh->msg2);
if (qh->msg1 > 0) {
assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler);
ssh->packet_dispatch[qh->msg1] = NULL;
}
if (qh->msg2 > 0) {
assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler);
ssh->packet_dispatch[qh->msg2] = NULL;
}
if (qh->next) {
ssh->qhead = qh->next;
if (ssh->qhead->msg1 > 0) {
assert(ssh->packet_dispatch[ssh->qhead->msg1] == NULL);
ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler;
}
if (ssh->qhead->msg2 > 0) {
assert(ssh->packet_dispatch[ssh->qhead->msg2] == NULL);
ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler;
}
} else {
ssh->qhead = ssh->qtail = NULL;
ssh->packet_dispatch[pktin->type] = NULL;
}
qh->handler(ssh, pktin, qh->ctx);
sfree(qh);
}
static void ssh_queue_handler(Ssh ssh, int msg1, int msg2,
chandler_fn_t handler, void *ctx)
{
struct queued_handler *qh;
qh = snew(struct queued_handler);
qh->msg1 = msg1;
qh->msg2 = msg2;
qh->handler = handler;
qh->ctx = ctx;
qh->next = NULL;
if (ssh->qtail == NULL) {
ssh->qhead = qh;
if (qh->msg1 > 0) {
assert(ssh->packet_dispatch[qh->msg1] == NULL);
ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler;
}
if (qh->msg2 > 0) {
assert(ssh->packet_dispatch[qh->msg2] == NULL);
ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler;
}
} else {
ssh->qtail->next = qh;
}
ssh->qtail = qh;
}
static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
{
struct ssh_rportfwd *rpf, *pf = (struct ssh_rportfwd *)ctx;
if (pktin->type == (ssh->version == 1 ? SSH1_SMSG_SUCCESS :
SSH2_MSG_REQUEST_SUCCESS)) {
logeventf(ssh, "Remote port forwarding from %s enabled",
pf->sportdesc);
} else {
logeventf(ssh, "Remote port forwarding from %s refused",
pf->sportdesc);
rpf = del234(ssh->rportfwds, pf);
assert(rpf == pf);
free_rportfwd(pf);
}
}
static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
{
const char *portfwd_strptr = cfg->portfwd;
struct ssh_portfwd *epf;
int i;
if (!ssh->portfwds) {
ssh->portfwds = newtree234(ssh_portcmp);
} else {
/*
* Go through the existing port forwardings and tag them
* with status==DESTROY. Any that we want to keep will be
* re-enabled (status==KEEP) as we go through the
* configuration and find out which bits are the same as
* they were before.
*/
struct ssh_portfwd *epf;
int i;
for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
epf->status = DESTROY;
}
while (*portfwd_strptr) {
char address_family, type;
int sport,dport,sserv,dserv;
char sports[256], dports[256], saddr[256], host[256];
int n;
address_family = 'A';
type = 'L';
if (*portfwd_strptr == 'A' ||
*portfwd_strptr == '4' ||
*portfwd_strptr == '6')
address_family = *portfwd_strptr++;
if (*portfwd_strptr == 'L' ||
*portfwd_strptr == 'R' ||
*portfwd_strptr == 'D')
type = *portfwd_strptr++;
saddr[0] = '\0';
n = 0;
while (*portfwd_strptr && *portfwd_strptr != '\t') {
if (*portfwd_strptr == ':') {
/*
* We've seen a colon in the middle of the
* source port number. This means that
* everything we've seen until now is the
* source _address_, so we'll move it into
* saddr and start sports from the beginning
* again.
*/
portfwd_strptr++;
sports[n] = '\0';
if (ssh->version == 1 && type == 'R') {
logeventf(ssh, "SSH1 cannot handle remote source address "
"spec \"%s\"; ignoring", sports);
} else
strcpy(saddr, sports);
n = 0;
}
if (n < 255) sports[n++] = *portfwd_strptr++;
}
sports[n] = 0;
if (type != 'D') {
if (*portfwd_strptr == '\t')
portfwd_strptr++;
n = 0;
while (*portfwd_strptr && *portfwd_strptr != ':') {
if (n < 255) host[n++] = *portfwd_strptr++;
}
host[n] = 0;
if (*portfwd_strptr == ':')
portfwd_strptr++;
n = 0;
while (*portfwd_strptr) {
if (n < 255) dports[n++] = *portfwd_strptr++;
}
dports[n] = 0;
portfwd_strptr++;
dport = atoi(dports);
dserv = 0;
if (dport == 0) {
dserv = 1;
dport = net_service_lookup(dports);
if (!dport) {
logeventf(ssh, "Service lookup failed for destination"
" port \"%s\"", dports);
}
}
} else {
while (*portfwd_strptr) portfwd_strptr++;
dport = dserv = -1;
portfwd_strptr++; /* eat the NUL and move to next one */
}
sport = atoi(sports);
sserv = 0;
if (sport == 0) {
sserv = 1;
sport = net_service_lookup(sports);
if (!sport) {
logeventf(ssh, "Service lookup failed for source"
" port \"%s\"", sports);
}
}
if (sport && dport) {
/* Set up a description of the source port. */
struct ssh_portfwd *pfrec, *epfrec;
pfrec = snew(struct ssh_portfwd);
pfrec->type = type;
pfrec->saddr = *saddr ? dupstr(saddr) : NULL;
pfrec->sserv = sserv ? dupstr(sports) : NULL;
pfrec->sport = sport;
pfrec->daddr = *host ? dupstr(host) : NULL;
pfrec->dserv = dserv ? dupstr(dports) : NULL;
pfrec->dport = dport;
pfrec->local = NULL;
pfrec->remote = NULL;
pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
address_family == '6' ? ADDRTYPE_IPV6 :
ADDRTYPE_UNSPEC);
epfrec = add234(ssh->portfwds, pfrec);
if (epfrec != pfrec) {
/*
* We already have a port forwarding with precisely
* these parameters. Hence, no need to do anything;
* simply tag the existing one as KEEP.
*/
epfrec->status = KEEP;
free_portfwd(pfrec);
} else {
pfrec->status = CREATE;
}
}
}
/*
* Now go through and destroy any port forwardings which were
* not re-enabled.
*/
for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
if (epf->status == DESTROY) {
char *message;
message = dupprintf("%s port forwarding from %s%s%d",
epf->type == 'L' ? "local" :
epf->type == 'R' ? "remote" : "dynamic",
epf->saddr ? epf->saddr : "",
epf->saddr ? ":" : "",
epf->sport);
if (epf->type != 'D') {
char *msg2 = dupprintf("%s to %s:%d", message,
epf->daddr, epf->dport);
sfree(message);
message = msg2;
}
logeventf(ssh, "Cancelling %s", message);
sfree(message);
if (epf->remote) {
struct ssh_rportfwd *rpf = epf->remote;
struct Packet *pktout;
/*
* Cancel the port forwarding at the server
* end.
*/
if (ssh->version == 1) {
/*
* We cannot cancel listening ports on the
* server side in SSH1! There's no message
* to support it. Instead, we simply remove
* the rportfwd record from the local end
* so that any connections the server tries
* to make on it are rejected.
*/
} else {
pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
if (epf->saddr) {
ssh2_pkt_addstring(pktout, epf->saddr);
} else if (ssh->cfg.rport_acceptall) {
/* XXX: ssh->cfg.rport_acceptall may not represent
* what was used to open the original connection,
* since it's reconfigurable. */
ssh2_pkt_addstring(pktout, "0.0.0.0");
} else {
ssh2_pkt_addstring(pktout, "127.0.0.1");
}
ssh2_pkt_adduint32(pktout, epf->sport);
ssh2_pkt_send(ssh, pktout);
}
del234(ssh->rportfwds, rpf);
free_rportfwd(rpf);
} else if (epf->local) {
pfd_terminate(epf->local);
}
delpos234(ssh->portfwds, i);
free_portfwd(epf);
i--; /* so we don't skip one in the list */
}
/*
* And finally, set up any new port forwardings (status==CREATE).
*/
for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
if (epf->status == CREATE) {
char *sportdesc, *dportdesc;
sportdesc = dupprintf("%s%s%s%s%d%s",
epf->saddr ? epf->saddr : "",
epf->saddr ? ":" : "",
epf->sserv ? epf->sserv : "",
epf->sserv ? "(" : "",
epf->sport,
epf->sserv ? ")" : "");
if (epf->type == 'D') {
dportdesc = NULL;
} else {
dportdesc = dupprintf("%s:%s%s%d%s",
epf->daddr,
epf->dserv ? epf->dserv : "",
epf->dserv ? "(" : "",
epf->dport,
epf->dserv ? ")" : "");
}
if (epf->type == 'L') {
const char *err = pfd_addforward(epf->daddr, epf->dport,
epf->saddr, epf->sport,
ssh, cfg,
&epf->local,
epf->addressfamily);
logeventf(ssh, "Local %sport %s forwarding to %s%s%s",
epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
sportdesc, dportdesc,
err ? " failed: " : "", err ? err : "");
} else if (epf->type == 'D') {
const char *err = pfd_addforward(NULL, -1,
epf->saddr, epf->sport,
ssh, cfg,
&epf->local,
epf->addressfamily);
logeventf(ssh, "Local %sport %s SOCKS dynamic forwarding%s%s",
epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
sportdesc,
err ? " failed: " : "", err ? err : "");
} else {
struct ssh_rportfwd *pf;
/*
* Ensure the remote port forwardings tree exists.
*/
if (!ssh->rportfwds) {
if (ssh->version == 1)
ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
else
ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
}
pf = snew(struct ssh_rportfwd);
strncpy(pf->dhost, epf->daddr, lenof(pf->dhost)-1);
pf->dhost[lenof(pf->dhost)-1] = '\0';
pf->dport = epf->dport;
pf->sport = epf->sport;
if (add234(ssh->rportfwds, pf) != pf) {
logeventf(ssh, "Duplicate remote port forwarding to %s:%d",
epf->daddr, epf->dport);
sfree(pf);
} else {
logeventf(ssh, "Requesting remote port %s"
" forward to %s", sportdesc, dportdesc);
pf->sportdesc = sportdesc;
sportdesc = NULL;
epf->remote = pf;
pf->pfrec = epf;
if (ssh->version == 1) {
send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
PKT_INT, epf->sport,
PKT_STR, epf->daddr,
PKT_INT, epf->dport,
PKT_END);
ssh_queue_handler(ssh, SSH1_SMSG_SUCCESS,
SSH1_SMSG_FAILURE,
ssh_rportfwd_succfail, pf);
} else {
struct Packet *pktout;
pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
ssh2_pkt_addstring(pktout, "tcpip-forward");
ssh2_pkt_addbool(pktout, 1);/* want reply */
if (epf->saddr) {
ssh2_pkt_addstring(pktout, epf->saddr);
} else if (cfg->rport_acceptall) {
ssh2_pkt_addstring(pktout, "0.0.0.0");
} else {
ssh2_pkt_addstring(pktout, "127.0.0.1");
}
ssh2_pkt_adduint32(pktout, epf->sport);
ssh2_pkt_send(ssh, pktout);
ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS,
SSH2_MSG_REQUEST_FAILURE,
ssh_rportfwd_succfail, pf);
}
}
}
sfree(sportdesc);
sfree(dportdesc);
}
}
static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
{
char *string;
int stringlen, bufsize;
ssh_pkt_getstring(pktin, &string, &stringlen);
if (string == NULL) {
bombout(("Incoming terminal data packet was badly formed"));
return;
}
bufsize = from_backend(ssh->frontend, pktin->type == SSH1_SMSG_STDERR_DATA,
string, stringlen);
if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
ssh->v1_stdout_throttling = 1;
ssh1_throttle(ssh, +1);
}
}
static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
{
/* Remote side is trying to open a channel to talk to our
* X-Server. Give them back a local channel number. */
struct ssh_channel *c;
int remoteid = ssh_pkt_getuint32(pktin);
logevent("Received X11 connect request");
/* Refuse if X11 forwarding is disabled. */
if (!ssh->X11_fwd_enabled) {
send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, remoteid, PKT_END);
logevent("Rejected X11 connect request");
} else {
c = snew(struct ssh_channel);
c->ssh = ssh;
if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
logevent("Opening X11 forward connection failed");
sfree(c);
send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, remoteid, PKT_END);
} else {
logevent
("Opening X11 forward connection succeeded");
c->remoteid = remoteid;
c->halfopen = FALSE;
c->localid = alloc_channel_id(ssh);
c->closes = 0;
c->v.v1.throttling = 0;
c->type = CHAN_X11; /* identify channel type */
add234(ssh->channels, c);
send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
PKT_INT, c->remoteid, PKT_INT,
c->localid, PKT_END);
logevent("Opened X11 forward channel");
}
}
}
static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
{
/* Remote side is trying to open a channel to talk to our
* agent. Give them back a local channel number. */
struct ssh_channel *c;
int remoteid = ssh_pkt_getuint32(pktin);
/* Refuse if agent forwarding is disabled. */
if (!ssh->agentfwd_enabled) {
send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, remoteid, PKT_END);
} else {
c = snew(struct ssh_channel);
c->ssh = ssh;
c->remoteid = remoteid;
c->halfopen = FALSE;
c->localid = alloc_channel_id(ssh);
c->closes = 0;
c->v.v1.throttling = 0;
c->type = CHAN_AGENT; /* identify channel type */
c->u.a.lensofar = 0;
add234(ssh->channels, c);
send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
PKT_INT, c->remoteid, PKT_INT, c->localid,
PKT_END);
}
}
static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
{
/* Remote side is trying to open a channel to talk to a
* forwarded port. Give them back a local channel number. */
struct ssh_channel *c;
struct ssh_rportfwd pf, *pfp;
int remoteid;
int hostsize, port;
char *host;
const char *e;
c = snew(struct ssh_channel);
c->ssh = ssh;
remoteid = ssh_pkt_getuint32(pktin);
ssh_pkt_getstring(pktin, &host, &hostsize);
port = ssh_pkt_getuint32(pktin);
if (hostsize >= lenof(pf.dhost))
hostsize = lenof(pf.dhost)-1;
memcpy(pf.dhost, host, hostsize);
pf.dhost[hostsize] = '\0';
pf.dport = port;
pfp = find234(ssh->rportfwds, &pf, NULL);
if (pfp == NULL) {
logeventf(ssh, "Rejected remote port open request for %s:%d",
pf.dhost, port);
send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, remoteid, PKT_END);
} else {
logeventf(ssh, "Received remote port open request for %s:%d",
pf.dhost, port);
e = pfd_newconnect(&c->u.pfd.s, pf.dhost, port,
c, &ssh->cfg, pfp->pfrec->addressfamily);
if (e != NULL) {
logeventf(ssh, "Port open failed: %s", e);
sfree(c);
send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, remoteid, PKT_END);
} else {
c->remoteid = remoteid;
c->halfopen = FALSE;
c->localid = alloc_channel_id(ssh);
c->closes = 0;
c->v.v1.throttling = 0;
c->type = CHAN_SOCKDATA; /* identify channel type */
add234(ssh->channels, c);
send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
PKT_INT, c->remoteid, PKT_INT,
c->localid, PKT_END);
logevent("Forwarded port opened successfully");
}
}
}
static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
{
unsigned int remoteid = ssh_pkt_getuint32(pktin);
unsigned int localid = ssh_pkt_getuint32(pktin);
struct ssh_channel *c;
c = find234(ssh->channels, &remoteid, ssh_channelfind);
if (c && c->type == CHAN_SOCKDATA_DORMANT) {
c->remoteid = localid;
c->halfopen = FALSE;
c->type = CHAN_SOCKDATA;
c->v.v1.throttling = 0;
pfd_confirm(c->u.pfd.s);
}
if (c && c->closes) {
/*
* We have a pending close on this channel,
* which we decided on before the server acked
* the channel open. So now we know the
* remoteid, we can close it again.
*/
send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
PKT_INT, c->remoteid, PKT_END);
}
}
static void ssh1_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
{
unsigned int remoteid = ssh_pkt_getuint32(pktin);
struct ssh_channel *c;
c = find234(ssh->channels, &remoteid, ssh_channelfind);
if (c && c->type == CHAN_SOCKDATA_DORMANT) {
logevent("Forwarded connection refused by server");
pfd_close(c->u.pfd.s);
del234(ssh->channels, c);
sfree(c);
}
}
static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin)
{
/* Remote side closes a channel. */
unsigned i = ssh_pkt_getuint32(pktin);
struct ssh_channel *c;
c = find234(ssh->channels, &i, ssh_channelfind);
if (c && !c->halfopen) {
int closetype;
closetype =
(pktin->type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
if ((c->closes == 0) && (c->type == CHAN_X11)) {
logevent("Forwarded X11 connection terminated");
assert(c->u.x11.s != NULL);
x11_close(c->u.x11.s);
c->u.x11.s = NULL;
}
if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
logevent("Forwarded port closed");
assert(c->u.pfd.s != NULL);
pfd_close(c->u.pfd.s);
c->u.pfd.s = NULL;
}
c->closes |= (closetype << 2); /* seen this message */
if (!(c->closes & closetype)) {
send_packet(ssh, pktin->type, PKT_INT, c->remoteid,
PKT_END);
c->closes |= closetype; /* sent it too */
}
if (c->closes == 15) {
del234(ssh->channels, c);
sfree(c);
}
} else {
bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" :
"_CONFIRMATION", c ? "half-open" : "nonexistent",
i));
}
}
static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
{
/* Data sent down one of our channels. */
int i = ssh_pkt_getuint32(pktin);
char *p;
int len;
struct ssh_channel *c;
ssh_pkt_getstring(pktin, &p, &len);
c = find234(ssh->channels, &i, ssh_channelfind);
if (c) {
int bufsize = 0;
switch (c->type) {
case CHAN_X11:
bufsize = x11_send(c->u.x11.s, p, len);
break;
case CHAN_SOCKDATA:
bufsize = pfd_send(c->u.pfd.s, p, len);
break;
case CHAN_AGENT:
/* Data for an agent message. Buffer it. */
while (len > 0) {
if (c->u.a.lensofar < 4) {
unsigned int l = min(4 - c->u.a.lensofar, len);
memcpy(c->u.a.msglen + c->u.a.lensofar, p,
l);
p += l;
len -= l;
c->u.a.lensofar += l;
}
if (c->u.a.lensofar == 4) {
c->u.a.totallen =
4 + GET_32BIT(c->u.a.msglen);
c->u.a.message = snewn(c->u.a.totallen,
unsigned char);
memcpy(c->u.a.message, c->u.a.msglen, 4);
}
if (c->u.a.lensofar >= 4 && len > 0) {
unsigned int l =
min(c->u.a.totallen - c->u.a.lensofar,
len);
memcpy(c->u.a.message + c->u.a.lensofar, p,
l);
p += l;
len -= l;
c->u.a.lensofar += l;
}
if (c->u.a.lensofar == c->u.a.totallen) {
void *reply;
int replylen;
if (agent_query(c->u.a.message,
c->u.a.totallen,
&reply, &replylen,
ssh_agentf_callback, c))
ssh_agentf_callback(c, reply, replylen);
sfree(c->u.a.message);
c->u.a.lensofar = 0;
}
}
bufsize = 0; /* agent channels never back up */
break;
}
if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
c->v.v1.throttling = 1;
ssh1_throttle(ssh, +1);
}
}
}
static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin)
{
ssh->exitcode = ssh_pkt_getuint32(pktin);
logeventf(ssh, "Server sent command exit status %d", ssh->exitcode);
send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
/*
* In case `helpful' firewalls or proxies tack
* extra human-readable text on the end of the
* session which we might mistake for another
* encrypted packet, we close the session once
* we've sent EXIT_CONFIRMATION.
*/
ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
}
static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
struct Packet *pktin)
{
crBegin(ssh->do_ssh1_connection_crstate);
ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] =
ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] =
ssh1_smsg_stdout_stderr_data;
ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] =
ssh1_msg_channel_open_confirmation;
ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] =
ssh1_msg_channel_open_failure;
ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] =
ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] =
ssh1_msg_channel_close;
ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data;
ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status;
if (ssh->cfg.agentfwd && agent_exists()) {
logevent("Requesting agent forwarding");
send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
do {
crReturnV;
} while (!pktin);
if (pktin->type != SSH1_SMSG_SUCCESS
&& pktin->type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crStopV;
} else if (pktin->type == SSH1_SMSG_FAILURE) {
logevent("Agent forwarding refused");
} else {
logevent("Agent forwarding enabled");
ssh->agentfwd_enabled = TRUE;
ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open;
}
}
if (ssh->cfg.x11_forward) {
char proto[20], data[64];
logevent("Requesting X11 forwarding");
ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
data, sizeof(data), ssh->cfg.x11_auth);
x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
PKT_STR, proto, PKT_STR, data,
PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
PKT_END);
} else {
send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
PKT_STR, proto, PKT_STR, data, PKT_END);
}
do {
crReturnV;
} while (!pktin);
if (pktin->type != SSH1_SMSG_SUCCESS
&& pktin->type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crStopV;
} else if (pktin->type == SSH1_SMSG_FAILURE) {
logevent("X11 forwarding refused");
} else {
logevent("X11 forwarding enabled");
ssh->X11_fwd_enabled = TRUE;
ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open;
}
}
ssh_setup_portfwd(ssh, &ssh->cfg);
ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open;
if (!ssh->cfg.nopty) {
/* Unpick the terminal-speed string. */
/* XXX perhaps we should allow no speeds to be sent. */
ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
/* Send the pty request. */
send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
PKT_STR, ssh->cfg.termtype,
PKT_INT, ssh->term_height,
PKT_INT, ssh->term_width,
PKT_INT, 0, PKT_INT, 0, /* width,height in pixels */
PKT_CHAR, 192, PKT_INT, ssh->ispeed, /* TTY_OP_ISPEED */
PKT_CHAR, 193, PKT_INT, ssh->ospeed, /* TTY_OP_OSPEED */
PKT_CHAR, 0, PKT_END);
ssh->state = SSH_STATE_INTERMED;
do {
crReturnV;
} while (!pktin);
if (pktin->type != SSH1_SMSG_SUCCESS
&& pktin->type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crStopV;
} else if (pktin->type == SSH1_SMSG_FAILURE) {
c_write_str(ssh, "Server refused to allocate pty\r\n");
ssh->editing = ssh->echoing = 1;
}
logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
ssh->ospeed, ssh->ispeed);
} else {
ssh->editing = ssh->echoing = 1;
}
if (ssh->cfg.compression) {
send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
do {
crReturnV;
} while (!pktin);
if (pktin->type != SSH1_SMSG_SUCCESS
&& pktin->type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crStopV;
} else if (pktin->type == SSH1_SMSG_FAILURE) {
c_write_str(ssh, "Server refused to compress\r\n");
}
logevent("Started compression");
ssh->v1_compressing = TRUE;
ssh->cs_comp_ctx = zlib_compress_init();
logevent("Initialised zlib (RFC1950) compression");
ssh->sc_comp_ctx = zlib_decompress_init();
logevent("Initialised zlib (RFC1950) decompression");
}
/*
* Start the shell or command.
*
* Special case: if the first-choice command is an SSH2
* subsystem (hence not usable here) and the second choice
* exists, we fall straight back to that.
*/
{
char *cmd = ssh->cfg.remote_cmd_ptr;
if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
cmd = ssh->cfg.remote_cmd_ptr2;
ssh->fallback_cmd = TRUE;
}
if (*cmd)
send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
else
send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
logevent("Started session");
}
ssh->state = SSH_STATE_SESSION;
if (ssh->size_needed)
ssh_size(ssh, ssh->term_width, ssh->term_height);
if (ssh->eof_needed)
ssh_special(ssh, TS_EOF);
if (ssh->ldisc)
ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
ssh->send_ok = 1;
ssh->channels = newtree234(ssh_channelcmp);
while (1) {
/*
* By this point, most incoming packets are already being
* handled by the dispatch table, and we need only pay
* attention to the unusual ones.
*/
crReturnV;
if (pktin) {
if (pktin->type == SSH1_SMSG_SUCCESS) {
/* may be from EXEC_SHELL on some servers */
} else if (pktin->type == SSH1_SMSG_FAILURE) {
/* may be from EXEC_SHELL on some servers
* if no pty is available or in other odd cases. Ignore */
} else {
bombout(("Strange packet received: type %d", pktin->type));
crStopV;
}
} else {
while (inlen > 0) {
int len = min(inlen, 512);
send_packet(ssh, SSH1_CMSG_STDIN_DATA, PKTT_DATA,
PKT_INT, len, PKT_DATA, in, len,
PKTT_OTHER, PKT_END);
in += len;
inlen -= len;
}
}
}
crFinishV;
}
/*
* Handle the top-level SSH2 protocol.
*/
static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
{
char *msg;
int msglen;
ssh_pkt_getstring(pktin, &msg, &msglen);
logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
}
static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
{
/* log reason code in disconnect message */
char *msg;
int msglen;
ssh_pkt_getstring(pktin, &msg, &msglen);
bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
}
static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
{
/* Do nothing, because we're ignoring it! Duhh. */
}
static void ssh1_protocol_setup(Ssh ssh)
{
int i;
/*
* Most messages are handled by the coroutines.
*/
for (i = 0; i < 256; i++)
ssh->packet_dispatch[i] = NULL;
/*
* These special message types we install handlers for.
*/
ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
}
static void ssh1_protocol(Ssh ssh, void *vin, int inlen,
struct Packet *pktin)
{
unsigned char *in=(unsigned char*)vin;
if (ssh->state == SSH_STATE_CLOSED)
return;
if (pktin && ssh->packet_dispatch[pktin->type]) {
ssh->packet_dispatch[pktin->type](ssh, pktin);
return;
}
if (!ssh->protocol_initial_phase_done) {
if (do_ssh1_login(ssh, in, inlen, pktin))
ssh->protocol_initial_phase_done = TRUE;
else
return;
}
do_ssh1_connection(ssh, in, inlen, pktin);
}
/*
* Utility routine for decoding comma-separated strings in KEXINIT.
*/
static int in_commasep_string(char *needle, char *haystack, int haylen)
{
int needlen;
if (!needle || !haystack) /* protect against null pointers */
return 0;
needlen = strlen(needle);
while (1) {
/*
* Is it at the start of the string?
*/
if (haylen >= needlen && /* haystack is long enough */
!memcmp(needle, haystack, needlen) && /* initial match */
(haylen == needlen || haystack[needlen] == ',')
/* either , or EOS follows */
)
return 1;
/*
* If not, search for the next comma and resume after that.
* If no comma found, terminate.
*/
while (haylen > 0 && *haystack != ',')
haylen--, haystack++;
if (haylen == 0)
return 0;
haylen--, haystack++; /* skip over comma itself */
}
}
/*
* Similar routine for checking whether we have the first string in a list.
*/
static int first_in_commasep_string(char *needle, char *haystack, int haylen)
{
int needlen;
if (!needle || !haystack) /* protect against null pointers */
return 0;
needlen = strlen(needle);
/*
* Is it at the start of the string?
*/
if (haylen >= needlen && /* haystack is long enough */
!memcmp(needle, haystack, needlen) && /* initial match */
(haylen == needlen || haystack[needlen] == ',')
/* either , or EOS follows */
)
return 1;
return 0;
}
/*
* SSH2 key creation method.
*/
static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
unsigned char *sessid, char chr,
unsigned char *keyspace)
{
SHA_State s;
/* First 20 bytes. */
SHA_Init(&s);
if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
sha_mpint(&s, K);
SHA_Bytes(&s, H, 20);
SHA_Bytes(&s, &chr, 1);
SHA_Bytes(&s, sessid, 20);
SHA_Final(&s, keyspace);
/* Next 20 bytes. */
SHA_Init(&s);
if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
sha_mpint(&s, K);
SHA_Bytes(&s, H, 20);
SHA_Bytes(&s, keyspace, 20);
SHA_Final(&s, keyspace + 20);
}
/*
* Handle the SSH2 transport layer.
*/
static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
struct Packet *pktin)
{
unsigned char *in = (unsigned char *)vin;
struct do_ssh2_transport_state {
int nbits, pbits, warn;
Bignum p, g, e, f, K;
int kex_init_value, kex_reply_value;
const struct ssh_mac **maclist;
int nmacs;
const struct ssh2_cipher *cscipher_tobe;
const struct ssh2_cipher *sccipher_tobe;
const struct ssh_mac *csmac_tobe;
const struct ssh_mac *scmac_tobe;
const struct ssh_compress *cscomp_tobe;
const struct ssh_compress *sccomp_tobe;
char *hostkeydata, *sigdata, *keystr, *fingerprint;
int hostkeylen, siglen;
void *hkey; /* actual host key */
unsigned char exchange_hash[20];
int n_preferred_kex;
const struct ssh_kex *preferred_kex[KEX_MAX];
int n_preferred_ciphers;
const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
const struct ssh_compress *preferred_comp;
int got_session_id, activated_authconn;
struct Packet *pktout;
};
crState(do_ssh2_transport_state);
crBegin(ssh->do_ssh2_transport_crstate);
s->cscipher_tobe = s->sccipher_tobe = NULL;
s->csmac_tobe = s->scmac_tobe = NULL;
s->cscomp_tobe = s->sccomp_tobe = NULL;
s->got_session_id = s->activated_authconn = FALSE;
/*
* Be prepared to work around the buggy MAC problem.
*/
if (ssh->remote_bugs & BUG_SSH2_HMAC)
s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
else
s->maclist = macs, s->nmacs = lenof(macs);
begin_key_exchange:
ssh->pkt_ctx &= ~SSH2_PKTCTX_KEX_MASK;
{
int i, j, commalist_started;
/*
* Set up the preferred key exchange. (NULL => warn below here)
*/
s->n_preferred_kex = 0;
for (i = 0; i < KEX_MAX; i++) {
switch (ssh->cfg.ssh_kexlist[i]) {
case KEX_DHGEX:
s->preferred_kex[s->n_preferred_kex++] =
&ssh_diffiehellman_gex;
break;
case KEX_DHGROUP14:
s->preferred_kex[s->n_preferred_kex++] =
&ssh_diffiehellman_group14;
break;
case KEX_DHGROUP1:
s->preferred_kex[s->n_preferred_kex++] =
&ssh_diffiehellman_group1;
break;
case CIPHER_WARN:
/* Flag for later. Don't bother if it's the last in
* the list. */
if (i < KEX_MAX - 1) {
s->preferred_kex[s->n_preferred_kex++] = NULL;
}
break;
}
}
/*
* Set up the preferred ciphers. (NULL => warn below here)
*/
s->n_preferred_ciphers = 0;
for (i = 0; i < CIPHER_MAX; i++) {
switch (ssh->cfg.ssh_cipherlist[i]) {
case CIPHER_BLOWFISH:
s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
break;
case CIPHER_DES:
if (ssh->cfg.ssh2_des_cbc) {
s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
}
break;
case CIPHER_3DES:
s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
break;
case CIPHER_AES:
s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
break;
case CIPHER_WARN:
/* Flag for later. Don't bother if it's the last in
* the list. */
if (i < CIPHER_MAX - 1) {
s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
}
break;
}
}
/*
* Set up preferred compression.
*/
if (ssh->cfg.compression)
s->preferred_comp = &ssh_zlib;
else
s->preferred_comp = &ssh_comp_none;
/*
* Enable queueing of outgoing auth- or connection-layer
* packets while we are in the middle of a key exchange.
*/
ssh->queueing = TRUE;
/*
* Flag that KEX is in progress.
*/
ssh->kex_in_progress = TRUE;
/*
* Construct and send our key exchange packet.
*/
s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
for (i = 0; i < 16; i++)
ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
/* List key exchange algorithms. */
ssh2_pkt_addstring_start(s->pktout);
commalist_started = 0;
for (i = 0; i < s->n_preferred_kex; i++) {
const struct ssh_kex *k = s->preferred_kex[i];
if (!k) continue; /* warning flag */
if (commalist_started)
ssh2_pkt_addstring_str(s->pktout, ",");
ssh2_pkt_addstring_str(s->pktout, s->preferred_kex[i]->name);
commalist_started = 1;
}
/* List server host key algorithms. */
ssh2_pkt_addstring_start(s->pktout);
for (i = 0; i < lenof(hostkey_algs); i++) {
ssh2_pkt_addstring_str(s->pktout, hostkey_algs[i]->name);
if (i < lenof(hostkey_algs) - 1)
ssh2_pkt_addstring_str(s->pktout, ",");
}
/* List client->server encryption algorithms. */
ssh2_pkt_addstring_start(s->pktout);
commalist_started = 0;
for (i = 0; i < s->n_preferred_ciphers; i++) {
const struct ssh2_ciphers *c = s->preferred_ciphers[i];
if (!c) continue; /* warning flag */
for (j = 0; j < c->nciphers; j++) {
if (commalist_started)
ssh2_pkt_addstring_str(s->pktout, ",");
ssh2_pkt_addstring_str(s->pktout, c->list[j]->name);
commalist_started = 1;
}
}
/* List server->client encryption algorithms. */
ssh2_pkt_addstring_start(s->pktout);
commalist_started = 0;
for (i = 0; i < s->n_preferred_ciphers; i++) {
const struct ssh2_ciphers *c = s->preferred_ciphers[i];
if (!c) continue; /* warning flag */
for (j = 0; j < c->nciphers; j++) {
if (commalist_started)
ssh2_pkt_addstring_str(s->pktout, ",");
ssh2_pkt_addstring_str(s->pktout, c->list[j]->name);
commalist_started = 1;
}
}
/* List client->server MAC algorithms. */
ssh2_pkt_addstring_start(s->pktout);
for (i = 0; i < s->nmacs; i++) {
ssh2_pkt_addstring_str(s->pktout, s->maclist[i]->name);
if (i < s->nmacs - 1)
ssh2_pkt_addstring_str(s->pktout, ",");
}
/* List server->client MAC algorithms. */
ssh2_pkt_addstring_start(s->pktout);
for (i = 0; i < s->nmacs; i++) {
ssh2_pkt_addstring_str(s->pktout, s->maclist[i]->name);
if (i < s->nmacs - 1)
ssh2_pkt_addstring_str(s->pktout, ",");
}
/* List client->server compression algorithms. */
ssh2_pkt_addstring_start(s->pktout);
assert(lenof(compressions) > 1);
ssh2_pkt_addstring_str(s->pktout, s->preferred_comp->name);
for (i = 0; i < lenof(compressions); i++) {
const struct ssh_compress *c = compressions[i];
if (c != s->preferred_comp) {
ssh2_pkt_addstring_str(s->pktout, ",");
ssh2_pkt_addstring_str(s->pktout, c->name);
}
}
/* List server->client compression algorithms. */
ssh2_pkt_addstring_start(s->pktout);
assert(lenof(compressions) > 1);
ssh2_pkt_addstring_str(s->pktout, s->preferred_comp->name);
for (i = 0; i < lenof(compressions); i++) {
const struct ssh_compress *c = compressions[i];
if (c != s->preferred_comp) {
ssh2_pkt_addstring_str(s->pktout, ",");
ssh2_pkt_addstring_str(s->pktout, c->name);
}
}
/* List client->server languages. Empty list. */
ssh2_pkt_addstring_start(s->pktout);
/* List server->client languages. Empty list. */
ssh2_pkt_addstring_start(s->pktout);
/* First KEX packet does _not_ follow, because we're not that brave. */
ssh2_pkt_addbool(s->pktout, FALSE);
/* Reserved. */
ssh2_pkt_adduint32(s->pktout, 0);
}
ssh->exhash = ssh->exhashbase;
sha_string(&ssh->exhash, s->pktout->data + 5, s->pktout->length - 5);
ssh2_pkt_send_noqueue(ssh, s->pktout);
if (!pktin)
crWaitUntil(pktin);
if (pktin->length > 5)
sha_string(&ssh->exhash, pktin->data + 5, pktin->length - 5);
/*
* Now examine the other side's KEXINIT to see what we're up
* to.
*/
{
char *str;
int i, j, len, guessok;
if (pktin->type != SSH2_MSG_KEXINIT) {
bombout(("expected key exchange packet from server"));
crStop(0);
}
ssh->kex = NULL;
ssh->hostkey = NULL;
s->cscipher_tobe = NULL;
s->sccipher_tobe = NULL;
s->csmac_tobe = NULL;
s->scmac_tobe = NULL;
s->cscomp_tobe = NULL;
s->sccomp_tobe = NULL;
pktin->savedpos += 16; /* skip garbage cookie */
ssh_pkt_getstring(pktin, &str, &len); /* key exchange algorithms */
s->warn = 0;
for (i = 0; i < s->n_preferred_kex; i++) {
const struct ssh_kex *k = s->preferred_kex[i];
if (!k) {
s->warn = 1;
} else if (in_commasep_string(k->name, str, len)) {
ssh->kex = k;
}
if (ssh->kex) {
if (s->warn) {
sk_set_frozen(ssh->s, 1);
askalg(ssh->frontend, "key-exchange algorithm",
ssh->kex->name);
sk_set_frozen(ssh->s, 0);
}
break;
}
}
if (!ssh->kex) {
bombout(("Couldn't agree a key exchange algorithm (available: %s)",
str ? str : "(null)"));
crStop(0);
}
/*
* Note that the server's guess is considered wrong if it doesn't match
* the first algorithm in our list, even if it's still the algorithm
* we end up using.
*/
guessok =
first_in_commasep_string(s->preferred_kex[0]->name, str, len);
ssh_pkt_getstring(pktin, &str, &len); /* host key algorithms */
for (i = 0; i < lenof(hostkey_algs); i++) {
if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
ssh->hostkey = hostkey_algs[i];
break;
}
}
guessok = guessok &&
first_in_commasep_string(hostkey_algs[0]->name, str, len);
ssh_pkt_getstring(pktin, &str, &len); /* client->server cipher */
s->warn = 0;
for (i = 0; i < s->n_preferred_ciphers; i++) {
const struct ssh2_ciphers *c = s->preferred_ciphers[i];
if (!c) {
s->warn = 1;
} else {
for (j = 0; j < c->nciphers; j++) {
if (in_commasep_string(c->list[j]->name, str, len)) {
s->cscipher_tobe = c->list[j];
break;
}
}
}
if (s->cscipher_tobe) {
if (s->warn) {
sk_set_frozen(ssh->s, 1);
askalg(ssh->frontend, "client-to-server cipher",
s->cscipher_tobe->name);
sk_set_frozen(ssh->s, 0);
}
break;
}
}
if (!s->cscipher_tobe) {
bombout(("Couldn't agree a client-to-server cipher (available: %s)",
str ? str : "(null)"));
crStop(0);
}
ssh_pkt_getstring(pktin, &str, &len); /* server->client cipher */
s->warn = 0;
for (i = 0; i < s->n_preferred_ciphers; i++) {
const struct ssh2_ciphers *c = s->preferred_ciphers[i];
if (!c) {
s->warn = 1;
} else {
for (j = 0; j < c->nciphers; j++) {
if (in_commasep_string(c->list[j]->name, str, len)) {
s->sccipher_tobe = c->list[j];
break;
}
}
}
if (s->sccipher_tobe) {
if (s->warn) {
sk_set_frozen(ssh->s, 1);
askalg(ssh->frontend, "server-to-client cipher",
s->sccipher_tobe->name);
sk_set_frozen(ssh->s, 0);
}
break;
}
}
if (!s->sccipher_tobe) {
bombout(("Couldn't agree a server-to-client cipher (available: %s)",
str ? str : "(null)"));
crStop(0);
}
ssh_pkt_getstring(pktin, &str, &len); /* client->server mac */
for (i = 0; i < s->nmacs; i++) {
if (in_commasep_string(s->maclist[i]->name, str, len)) {
s->csmac_tobe = s->maclist[i];
break;
}
}
ssh_pkt_getstring(pktin, &str, &len); /* server->client mac */
for (i = 0; i < s->nmacs; i++) {
if (in_commasep_string(s->maclist[i]->name, str, len)) {
s->scmac_tobe = s->maclist[i];
break;
}
}
ssh_pkt_getstring(pktin, &str, &len); /* client->server compression */
for (i = 0; i < lenof(compressions) + 1; i++) {
const struct ssh_compress *c =
i == 0 ? s->preferred_comp : compressions[i - 1];
if (in_commasep_string(c->name, str, len)) {
s->cscomp_tobe = c;
break;
}
}
ssh_pkt_getstring(pktin, &str, &len); /* server->client compression */
for (i = 0; i < lenof(compressions) + 1; i++) {
const struct ssh_compress *c =
i == 0 ? s->preferred_comp : compressions[i - 1];
if (in_commasep_string(c->name, str, len)) {
s->sccomp_tobe = c;
break;
}
}
ssh_pkt_getstring(pktin, &str, &len); /* client->server language */
ssh_pkt_getstring(pktin, &str, &len); /* server->client language */
if (ssh2_pkt_getbool(pktin) && !guessok) /* first_kex_packet_follows */
crWaitUntil(pktin); /* Ignore packet */
}
/*
* Work out the number of bits of key we will need from the key
* exchange. We start with the maximum key length of either
* cipher...
*/
{
int csbits, scbits;
csbits = s->cscipher_tobe->keylen;
scbits = s->sccipher_tobe->keylen;
s->nbits = (csbits > scbits ? csbits : scbits);
}
/* The keys only have 160-bit entropy, since they're based on
* a SHA-1 hash. So cap the key size at 160 bits. */
if (s->nbits > 160)
s->nbits = 160;
/*
* If we're doing Diffie-Hellman group exchange, start by
* requesting a group.
*/
if (!ssh->kex->pdata) {
logevent("Doing Diffie-Hellman group exchange");
ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
/*
* Work out how big a DH group we will need to allow that
* much data.
*/
s->pbits = 512 << ((s->nbits - 1) / 64);
s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
ssh2_pkt_adduint32(s->pktout, s->pbits);
ssh2_pkt_send_noqueue(ssh, s->pktout);
crWaitUntil(pktin);
if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
bombout(("expected key exchange group packet from server"));
crStop(0);
}
s->p = ssh2_pkt_getmp(pktin);
s->g = ssh2_pkt_getmp(pktin);
if (!s->p || !s->g) {
bombout(("unable to read mp-ints from incoming group packet"));
crStop(0);
}
ssh->kex_ctx = dh_setup_gex(s->p, s->g);
s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
} else {
ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP;
ssh->kex_ctx = dh_setup_group(ssh->kex);
s->kex_init_value = SSH2_MSG_KEXDH_INIT;
s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
ssh->kex->groupname);
}
logevent("Doing Diffie-Hellman key exchange");
/*
* Now generate and send e for Diffie-Hellman.
*/
s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
s->pktout = ssh2_pkt_init(s->kex_init_value);
ssh2_pkt_addmp(s->pktout, s->e);
ssh2_pkt_send_noqueue(ssh, s->pktout);
crWaitUntil(pktin);
if (pktin->type != s->kex_reply_value) {
bombout(("expected key exchange reply packet from server"));
crStop(0);
}
ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
s->f = ssh2_pkt_getmp(pktin);
if (!s->f) {
bombout(("unable to parse key exchange reply packet"));
crStop(0);
}
ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
s->K = dh_find_K(ssh->kex_ctx, s->f);
sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
if (ssh->kex == &ssh_diffiehellman_gex) {
sha_uint32(&ssh->exhash, s->pbits);
sha_mpint(&ssh->exhash, s->p);
sha_mpint(&ssh->exhash, s->g);
}
sha_mpint(&ssh->exhash, s->e);
sha_mpint(&ssh->exhash, s->f);
sha_mpint(&ssh->exhash, s->K);
SHA_Final(&ssh->exhash, s->exchange_hash);
dh_cleanup(ssh->kex_ctx);
ssh->kex_ctx = NULL;
#if 0
debug(("Exchange hash is:\n"));
dmemdump(s->exchange_hash, 20);
#endif
s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
if (!s->hkey ||
!ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
(char *)s->exchange_hash, 20)) {
bombout(("Server's host key did not match the signature supplied"));
crStop(0);
}
/*
* Authenticate remote host: verify host key. (We've already
* checked the signature of the exchange hash.)
*/
s->keystr = ssh->hostkey->fmtkey(s->hkey);
s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
sk_set_frozen(ssh->s, 1);
verify_ssh_host_key(ssh->frontend,
ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
s->keystr, s->fingerprint);
sk_set_frozen(ssh->s, 0);
if (!s->got_session_id) { /* don't bother logging this in rekeys */
logevent("Host key fingerprint is:");
logevent(s->fingerprint);
}
sfree(s->fingerprint);
sfree(s->keystr);
ssh->hostkey->freekey(s->hkey);
/*
* The exchange hash from the very first key exchange is also
* the session id, used in session key construction and
* authentication.
*/
if (!s->got_session_id) {
memcpy(ssh->v2_session_id, s->exchange_hash,
sizeof(s->exchange_hash));
s->got_session_id = TRUE;
}
/*
* Send SSH2_MSG_NEWKEYS.
*/
s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS);
ssh2_pkt_send_noqueue(ssh, s->pktout);
ssh->outgoing_data_size = 0; /* start counting from here */
/*
* We've sent client NEWKEYS, so create and initialise
* client-to-server session keys.
*/
if (ssh->cs_cipher_ctx)
ssh->cscipher->free_context(ssh->cs_cipher_ctx);
ssh->cscipher = s->cscipher_tobe;
ssh->cs_cipher_ctx = ssh->cscipher->make_context();
if (ssh->cs_mac_ctx)
ssh->csmac->free_context(ssh->cs_mac_ctx);
ssh->csmac = s->csmac_tobe;
ssh->cs_mac_ctx = ssh->csmac->make_context();
if (ssh->cs_comp_ctx)
ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
ssh->cscomp = s->cscomp_tobe;
ssh->cs_comp_ctx = ssh->cscomp->compress_init();
/*
* Set IVs on client-to-server keys. Here we use the exchange
* hash from the _first_ key exchange.
*/
{
unsigned char keyspace[40];
ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
}
logeventf(ssh, "Initialised %.200s client->server encryption",
ssh->cscipher->text_name);
logeventf(ssh, "Initialised %.200s client->server MAC algorithm",
ssh->csmac->text_name);
if (ssh->cscomp->text_name)
logeventf(ssh, "Initialised %s compression",
ssh->cscomp->text_name);
/*
* Now our end of the key exchange is complete, we can send all
* our queued higher-layer packets.
*/
ssh->queueing = FALSE;
ssh2_pkt_queuesend(ssh);
/*
* Expect SSH2_MSG_NEWKEYS from server.
*/
crWaitUntil(pktin);
if (pktin->type != SSH2_MSG_NEWKEYS) {
bombout(("expected new-keys packet from server"));
crStop(0);
}
ssh->incoming_data_size = 0; /* start counting from here */
/*
* We've seen server NEWKEYS, so create and initialise
* server-to-client session keys.
*/
if (ssh->sc_cipher_ctx)
ssh->sccipher->free_context(ssh->sc_cipher_ctx);
ssh->sccipher = s->sccipher_tobe;
ssh->sc_cipher_ctx = ssh->sccipher->make_context();
if (ssh->sc_mac_ctx)
ssh->scmac->free_context(ssh->sc_mac_ctx);
ssh->scmac = s->scmac_tobe;
ssh->sc_mac_ctx = ssh->scmac->make_context();
if (ssh->sc_comp_ctx)
ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
ssh->sccomp = s->sccomp_tobe;
ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
/*
* Set IVs on server-to-client keys. Here we use the exchange
* hash from the _first_ key exchange.
*/
{
unsigned char keyspace[40];
ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
}
logeventf(ssh, "Initialised %.200s server->client encryption",
ssh->sccipher->text_name);
logeventf(ssh, "Initialised %.200s server->client MAC algorithm",
ssh->scmac->text_name);
if (ssh->sccomp->text_name)
logeventf(ssh, "Initialised %s decompression",
ssh->sccomp->text_name);
/*
* Free key exchange data.
*/
freebn(s->f);
freebn(s->K);
if (ssh->kex == &ssh_diffiehellman_gex) {
freebn(s->g);
freebn(s->p);
}
/*
* Key exchange is over. Loop straight back round if we have a
* deferred rekey reason.
*/
if (ssh->deferred_rekey_reason) {
logevent(ssh->deferred_rekey_reason);
pktin = NULL;
ssh->deferred_rekey_reason = NULL;
goto begin_key_exchange;
}
/*
* Otherwise, schedule a timer for our next rekey.
*/
ssh->kex_in_progress = FALSE;
ssh->last_rekey = GETTICKCOUNT();
if (ssh->cfg.ssh_rekey_time != 0)
ssh->next_rekey = schedule_timer(ssh->cfg.ssh_rekey_time*60*TICKSPERSEC,
ssh2_timer, ssh);
/*
* If this is the first key exchange phase, we must pass the
* SSH2_MSG_NEWKEYS packet to the next layer, not because it
* wants to see it but because it will need time to initialise
* itself before it sees an actual packet. In subsequent key
* exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
* it would only confuse the layer above.
*/
if (s->activated_authconn) {
crReturn(1);
}
s->activated_authconn = TRUE;
/*
* Now we're encrypting. Begin returning 1 to the protocol main
* function so that other things can run on top of the
* transport. If we ever see a KEXINIT, we must go back to the
* start.
*
* We _also_ go back to the start if we see pktin==NULL and
* inlen==-1, because this is a special signal meaning
* `initiate client-driven rekey', and `in' contains a message
* giving the reason for the rekey.
*/
while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) ||
(!pktin && inlen == -1))) {
wait_for_rekey:
crReturn(1);
}
if (pktin) {
logevent("Server initiated key re-exchange");
} else {
/*
* Special case: if the server bug is set that doesn't
* allow rekeying, we give a different log message and
* continue waiting. (If such a server _initiates_ a rekey,
* we process it anyway!)
*/
if ((ssh->remote_bugs & BUG_SSH2_REKEY)) {
logeventf(ssh, "Server bug prevents key re-exchange (%s)",
(char *)in);
/* Reset the counters, so that at least this message doesn't
* hit the event log _too_ often. */
ssh->outgoing_data_size = 0;
ssh->incoming_data_size = 0;
if (ssh->cfg.ssh_rekey_time != 0) {
ssh->next_rekey =
schedule_timer(ssh->cfg.ssh_rekey_time*60*TICKSPERSEC,
ssh2_timer, ssh);
}
goto wait_for_rekey; /* this is utterly horrid */
} else {
logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in);
}
}
goto begin_key_exchange;
crFinish(1);
}
/*
* Add data to an SSH2 channel output buffer.
*/
static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
int len)
{
bufchain_add(&c->v.v2.outbuffer, buf, len);
}
/*
* Attempt to send data on an SSH2 channel.
*/
static int ssh2_try_send(struct ssh_channel *c)
{
Ssh ssh = c->ssh;
struct Packet *pktout;
while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
int len;
void *data;
bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
if ((unsigned)len > c->v.v2.remwindow)
len = c->v.v2.remwindow;
if ((unsigned)len > c->v.v2.remmaxpkt)
len = c->v.v2.remmaxpkt;
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
ssh2_pkt_adduint32(pktout, c->remoteid);
dont_log_data(ssh, pktout, PKTLOG_OMIT);
ssh2_pkt_addstring_start(pktout);
ssh2_pkt_addstring_data(pktout, data, len);
end_log_omission(ssh, pktout);
ssh2_pkt_send(ssh, pktout);
bufchain_consume(&c->v.v2.outbuffer, len);
c->v.v2.remwindow -= len;
}
/*
* After having sent as much data as we can, return the amount
* still buffered.
*/
return bufchain_size(&c->v.v2.outbuffer);
}
/*
* Potentially enlarge the window on an SSH2 channel.
*/
static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
{
Ssh ssh = c->ssh;
/*
* Never send WINDOW_ADJUST for a channel that the remote side
* already thinks it's closed; there's no point, since it won't
* be sending any more data anyway.
*/
if (c->closes != 0)
return;
/*
* Only send a WINDOW_ADJUST if there's significantly more window
* available than the other end thinks there is. This saves us
* sending a WINDOW_ADJUST for every character in a shell session.
*
* "Significant" is arbitrarily defined as half the window size.
*/
if (newwin > c->v.v2.locwindow * 2) {
struct Packet *pktout;
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
ssh2_pkt_send(ssh, pktout);
c->v.v2.locwindow = newwin;
}
}
static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
{
unsigned i = ssh_pkt_getuint32(pktin);
struct ssh_channel *c;
c = find234(ssh->channels, &i, ssh_channelfind);
if (c && !c->closes)
c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
}
static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
{
char *data;
int length;
unsigned i = ssh_pkt_getuint32(pktin);
struct ssh_channel *c;
c = find234(ssh->channels, &i, ssh_channelfind);
if (!c)
return; /* nonexistent channel */
if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
return; /* extended but not stderr */
ssh_pkt_getstring(pktin, &data, &length);
if (data) {
int bufsize = 0;
c->v.v2.locwindow -= length;
switch (c->type) {
case CHAN_MAINSESSION:
bufsize =
from_backend(ssh->frontend, pktin->type ==
SSH2_MSG_CHANNEL_EXTENDED_DATA,
data, length);
break;
case CHAN_X11:
bufsize = x11_send(c->u.x11.s, data, length);
break;
case CHAN_SOCKDATA:
bufsize = pfd_send(c->u.pfd.s, data, length);
break;
case CHAN_AGENT:
while (length > 0) {
if (c->u.a.lensofar < 4) {
unsigned int l = min(4 - c->u.a.lensofar, length);
memcpy(c->u.a.msglen + c->u.a.lensofar,
data, l);
data += l;
length -= l;
c->u.a.lensofar += l;
}
if (c->u.a.lensofar == 4) {
c->u.a.totallen =
4 + GET_32BIT(c->u.a.msglen);
c->u.a.message = snewn(c->u.a.totallen,
unsigned char);
memcpy(c->u.a.message, c->u.a.msglen, 4);
}
if (c->u.a.lensofar >= 4 && length > 0) {
unsigned int l =
min(c->u.a.totallen - c->u.a.lensofar,
length);
memcpy(c->u.a.message + c->u.a.lensofar,
data, l);
data += l;
length -= l;
c->u.a.lensofar += l;
}
if (c->u.a.lensofar == c->u.a.totallen) {
void *reply;
int replylen;
if (agent_query(c->u.a.message,
c->u.a.totallen,
&reply, &replylen,
ssh_agentf_callback, c))
ssh_agentf_callback(c, reply, replylen);
sfree(c->u.a.message);
c->u.a.lensofar = 0;
}
}
bufsize = 0;
break;
}
/*
* If we are not buffering too much data,
* enlarge the window again at the remote side.
*/
if (bufsize < OUR_V2_WINSIZE)
ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
}
}
static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
{
unsigned i = ssh_pkt_getuint32(pktin);
struct ssh_channel *c;
c = find234(ssh->channels, &i, ssh_channelfind);
if (!c)
return; /* nonexistent channel */
if (c->type == CHAN_X11) {
/*
* Remote EOF on an X11 channel means we should
* wrap up and close the channel ourselves.
*/
x11_close(c->u.x11.s);
sshfwd_close(c);
} else if (c->type == CHAN_AGENT) {
sshfwd_close(c);
} else if (c->type == CHAN_SOCKDATA) {
pfd_close(c->u.pfd.s);
sshfwd_close(c);
}
}
static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
{
unsigned i = ssh_pkt_getuint32(pktin);
struct ssh_channel *c;
struct Packet *pktout;
c = find234(ssh->channels, &i, ssh_channelfind);
if (!c || c->halfopen) {
bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
c ? "half-open" : "nonexistent", i));
return;
}
/* Do pre-close processing on the channel. */
switch (c->type) {
case CHAN_MAINSESSION:
ssh->mainchan = NULL;
update_specials_menu(ssh->frontend);
break;
case CHAN_X11:
if (c->u.x11.s != NULL)
x11_close(c->u.x11.s);
sshfwd_close(c);
break;
case CHAN_AGENT:
sshfwd_close(c);
break;
case CHAN_SOCKDATA:
if (c->u.pfd.s != NULL)
pfd_close(c->u.pfd.s);
sshfwd_close(c);
break;
}
if (c->closes == 0) {
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_send(ssh, pktout);
}
del234(ssh->channels, c);
bufchain_clear(&c->v.v2.outbuffer);
sfree(c);
/*
* See if that was the last channel left open.
* (This is only our termination condition if we're
* not running in -N mode.)
*/
if (!ssh->cfg.ssh_no_shell && count234(ssh->channels) == 0) {
logevent("All channels closed. Disconnecting");
#if 0
/*
* We used to send SSH_MSG_DISCONNECT here,
* because I'd believed that _every_ conforming
* SSH2 connection had to end with a disconnect
* being sent by at least one side; apparently
* I was wrong and it's perfectly OK to
* unceremoniously slam the connection shut
* when you're done, and indeed OpenSSH feels
* this is more polite than sending a
* DISCONNECT. So now we don't.
*/
s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
ssh2_pkt_adduint32(s->pktout, SSH2_DISCONNECT_BY_APPLICATION);
ssh2_pkt_addstring(s->pktout, "All open channels closed");
ssh2_pkt_addstring(s->pktout, "en"); /* language tag */
ssh2_pkt_send_noqueue(ssh, s->pktout);
#endif
ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
}
}
static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
{
unsigned i = ssh_pkt_getuint32(pktin);
struct ssh_channel *c;
struct Packet *pktout;
c = find234(ssh->channels, &i, ssh_channelfind);
if (!c)
return; /* nonexistent channel */
if (c->type != CHAN_SOCKDATA_DORMANT)
return; /* dunno why they're confirming this */
c->remoteid = ssh_pkt_getuint32(pktin);
c->halfopen = FALSE;
c->type = CHAN_SOCKDATA;
c->v.v2.remwindow = ssh_pkt_getuint32(pktin);
c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
if (c->u.pfd.s)
pfd_confirm(c->u.pfd.s);
if (c->closes) {
/*
* We have a pending close on this channel,
* which we decided on before the server acked
* the channel open. So now we know the
* remoteid, we can close it again.
*/
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_send(ssh, pktout);
}
}
static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
{
static const char *const reasons[] = {
"<unknown reason code>",
"Administratively prohibited",
"Connect failed",
"Unknown channel type",
"Resource shortage",
};
unsigned i = ssh_pkt_getuint32(pktin);
unsigned reason_code;
char *reason_string;
int reason_length;
struct ssh_channel *c;
c = find234(ssh->channels, &i, ssh_channelfind);
if (!c)
return; /* nonexistent channel */
if (c->type != CHAN_SOCKDATA_DORMANT)
return; /* dunno why they're failing this */
reason_code = ssh_pkt_getuint32(pktin);
if (reason_code >= lenof(reasons))
reason_code = 0; /* ensure reasons[reason_code] in range */
ssh_pkt_getstring(pktin, &reason_string, &reason_length);
logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]",
reasons[reason_code], reason_length, reason_string);
pfd_close(c->u.pfd.s);
del234(ssh->channels, c);
sfree(c);
}
static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
{
unsigned localid;
char *type;
int typelen, want_reply;
int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
struct ssh_channel *c;
struct Packet *pktout;
localid = ssh_pkt_getuint32(pktin);
ssh_pkt_getstring(pktin, &type, &typelen);
want_reply = ssh2_pkt_getbool(pktin);
/*
* First, check that the channel exists. Otherwise,
* we can instantly disconnect with a rude message.
*/
c = find234(ssh->channels, &localid, ssh_channelfind);
if (!c) {
char buf[80];
sprintf(buf, "Received channel request for nonexistent"
" channel %d", localid);
logevent(buf);
pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
ssh2_pkt_adduint32(pktout, SSH2_DISCONNECT_BY_APPLICATION);
ssh2_pkt_addstring(pktout, buf);
ssh2_pkt_addstring(pktout, "en"); /* language tag */
ssh2_pkt_send_noqueue(ssh, pktout);
connection_fatal(ssh->frontend, "%s", buf);
ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
return;
}
/*
* Having got the channel number, we now look at
* the request type string to see if it's something
* we recognise.
*/
if (c == ssh->mainchan) {
/*
* We recognise "exit-status" and "exit-signal" on
* the primary channel.
*/
if (typelen == 11 &&
!memcmp(type, "exit-status", 11)) {
ssh->exitcode = ssh_pkt_getuint32(pktin);
logeventf(ssh, "Server sent command exit status %d",
ssh->exitcode);
reply = SSH2_MSG_CHANNEL_SUCCESS;
} else if (typelen == 11 &&
!memcmp(type, "exit-signal", 11)) {
int is_plausible = TRUE, is_int = FALSE;
char *fmt_sig = "", *fmt_msg = "";
char *msg;
int msglen = 0, core = FALSE;
/* ICK: older versions of OpenSSH (e.g. 3.4p1)
* provide an `int' for the signal, despite its
* having been a `string' in the drafts since at
* least 2001. (Fixed in session.c 1.147.) Try to
* infer which we can safely parse it as. */
{
unsigned char *p = pktin->body +
pktin->savedpos;
long len = pktin->length - pktin->savedpos;
unsigned long num = GET_32BIT(p); /* what is it? */
/* If it's 0, it hardly matters; assume string */
if (num == 0) {
is_int = FALSE;
} else {
int maybe_int = FALSE, maybe_str = FALSE;
#define CHECK_HYPOTHESIS(offset, result) \
do { \
long q = offset; \
if (q >= 0 && q+4 <= len) { \
q = q + 4 + GET_32BIT(p+q); \
if (q >= 0 && q+4 <= len && \
((q = q + 4 + GET_32BIT(p+q))!= 0) && q == len) \
result = TRUE; \
} \
} while(0)
CHECK_HYPOTHESIS(4+1, maybe_int);
CHECK_HYPOTHESIS(4+num+1, maybe_str);
#undef CHECK_HYPOTHESIS
if (maybe_int && !maybe_str)
is_int = TRUE;
else if (!maybe_int && maybe_str)
is_int = FALSE;
else
/* Crikey. Either or neither. Panic. */
is_plausible = FALSE;
}
}
if (is_plausible) {
if (is_int) {
/* Old non-standard OpenSSH. */
int signum = ssh_pkt_getuint32(pktin);
fmt_sig = dupprintf(" %d", signum);
} else {
/* As per the drafts. */
char *sig;
int siglen;
ssh_pkt_getstring(pktin, &sig, &siglen);
/* Signal name isn't supposed to be blank, but
* let's cope gracefully if it is. */
if (siglen) {
fmt_sig = dupprintf(" \"%.*s\"",
siglen, sig);
}
}
core = ssh2_pkt_getbool(pktin);
ssh_pkt_getstring(pktin, &msg, &msglen);
if (msglen) {
fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg);
}
/* ignore lang tag */
} /* else don't attempt to parse */
logeventf(ssh, "Server exited on signal%s%s%s",
fmt_sig, core ? " (core dumped)" : "",
fmt_msg);
if (*fmt_sig) sfree(fmt_sig);
if (*fmt_msg) sfree(fmt_msg);
reply = SSH2_MSG_CHANNEL_SUCCESS;
}
} else {
/*
* This is a channel request we don't know
* about, so we now either ignore the request
* or respond with CHANNEL_FAILURE, depending
* on want_reply.
*/
reply = SSH2_MSG_CHANNEL_FAILURE;
}
if (want_reply) {
pktout = ssh2_pkt_init(reply);
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_send(ssh, pktout);
}
}
static void ssh2_msg_global_request(Ssh ssh, struct Packet *pktin)
{
char *type;
int typelen, want_reply;
struct Packet *pktout;
ssh_pkt_getstring(pktin, &type, &typelen);
want_reply = ssh2_pkt_getbool(pktin);
/*
* We currently don't support any global requests
* at all, so we either ignore the request or
* respond with REQUEST_FAILURE, depending on
* want_reply.
*/
if (want_reply) {
pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE);
ssh2_pkt_send(ssh, pktout);
}
}
static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
{
char *type;
int typelen;
char *peeraddr;
int peeraddrlen;
int peerport;
char *error = NULL;
struct ssh_channel *c;
unsigned remid, winsize, pktsize;
struct Packet *pktout;
ssh_pkt_getstring(pktin, &type, &typelen);
c = snew(struct ssh_channel);
c->ssh = ssh;
remid = ssh_pkt_getuint32(pktin);
winsize = ssh_pkt_getuint32(pktin);
pktsize = ssh_pkt_getuint32(pktin);
if (typelen == 3 && !memcmp(type, "x11", 3)) {
char *addrstr;
ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
addrstr = snewn(peeraddrlen+1, char);
memcpy(addrstr, peeraddr, peeraddrlen);
addrstr[peeraddrlen] = '\0';
peerport = ssh_pkt_getuint32(pktin);
logeventf(ssh, "Received X11 connect request from %s:%d",
addrstr, peerport);
if (!ssh->X11_fwd_enabled)
error = "X11 forwarding is not enabled";
else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
ssh->x11auth, addrstr, peerport,
&ssh->cfg) != NULL) {
error = "Unable to open an X11 connection";
} else {
logevent("Opening X11 forward connection succeeded");
c->type = CHAN_X11;
}
sfree(addrstr);
} else if (typelen == 15 &&
!memcmp(type, "forwarded-tcpip", 15)) {
struct ssh_rportfwd pf, *realpf;
char *dummy;
int dummylen;
ssh_pkt_getstring(pktin, &dummy, &dummylen);/* skip address */
pf.sport = ssh_pkt_getuint32(pktin);
ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
peerport = ssh_pkt_getuint32(pktin);
realpf = find234(ssh->rportfwds, &pf, NULL);
logeventf(ssh, "Received remote port %d open request "
"from %s:%d", pf.sport, peeraddr, peerport);
if (realpf == NULL) {
error = "Remote port is not recognised";
} else {
const char *e = pfd_newconnect(&c->u.pfd.s,
realpf->dhost,
realpf->dport, c,
&ssh->cfg,
realpf->pfrec->addressfamily);
logeventf(ssh, "Attempting to forward remote port to "
"%s:%d", realpf->dhost, realpf->dport);
if (e != NULL) {
logeventf(ssh, "Port open failed: %s", e);
error = "Port open failed";
} else {
logevent("Forwarded port opened successfully");
c->type = CHAN_SOCKDATA;
}
}
} else if (typelen == 22 &&
!memcmp(type, "auth-agent@openssh.com", 3)) {
if (!ssh->agentfwd_enabled)
error = "Agent forwarding is not enabled";
else {
c->type = CHAN_AGENT; /* identify channel type */
c->u.a.lensofar = 0;
}
} else {
error = "Unsupported channel type requested";
}
c->remoteid = remid;
c->halfopen = FALSE;
if (error) {
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_adduint32(pktout, SSH2_OPEN_CONNECT_FAILED);
ssh2_pkt_addstring(pktout, error);
ssh2_pkt_addstring(pktout, "en"); /* language tag */
ssh2_pkt_send(ssh, pktout);
logeventf(ssh, "Rejected channel open: %s", error);
sfree(c);
} else {
c->localid = alloc_channel_id(ssh);
c->closes = 0;
c->v.v2.locwindow = OUR_V2_WINSIZE;
c->v.v2.remwindow = winsize;
c->v.v2.remmaxpkt = pktsize;
bufchain_init(&c->v.v2.outbuffer);
add234(ssh->channels, c);
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_adduint32(pktout, c->localid);
ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);
ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
ssh2_pkt_send(ssh, pktout);
}
}
/*
* Handle the SSH2 userauth and connection layers.
*/
static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
struct Packet *pktin)
{
struct do_ssh2_authconn_state {
enum {
AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
AUTH_PASSWORD,
AUTH_KEYBOARD_INTERACTIVE
} method;
enum {
AUTH_TYPE_NONE,
AUTH_TYPE_PUBLICKEY,
AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
AUTH_TYPE_PASSWORD,
AUTH_TYPE_KEYBOARD_INTERACTIVE,
AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
} type;
int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
int tried_pubkey_config, tried_agent;
int kbd_inter_running, kbd_inter_refused;
int we_are_in;
int num_prompts, curr_prompt, echo;
char username[100];
int got_username;
char pwprompt[512];
char password[100];
void *publickey_blob;
int publickey_bloblen;
unsigned char request[5], *response, *p;
int responselen;
int keyi, nkeys;
int authed;
char *pkblob, *alg, *commentp;
int pklen, alglen, commentlen;
int siglen, retlen, len;
char *q, *agentreq, *ret;
int try_send;
int num_env, env_left, env_ok;
struct Packet *pktout;
};
crState(do_ssh2_authconn_state);
crBegin(ssh->do_ssh2_authconn_crstate);
/*
* Request userauth protocol, and await a response to it.
*/
s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
ssh2_pkt_addstring(s->pktout, "ssh-userauth");
ssh2_pkt_send(ssh, s->pktout);
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_SERVICE_ACCEPT) {
bombout(("Server refused user authentication protocol"));
crStopV;
}
/*
* We repeat this whole loop, including the username prompt,
* until we manage a successful authentication. If the user
* types the wrong _password_, they can be sent back to the
* beginning to try another username, if this is configured on.
* (If they specify a username in the config, they are never
* asked, even if they do give a wrong password.)
*
* I think this best serves the needs of
*
* - the people who have no configuration, no keys, and just
* want to try repeated (username,password) pairs until they
* type both correctly
*
* - people who have keys and configuration but occasionally
* need to fall back to passwords
*
* - people with a key held in Pageant, who might not have
* logged in to a particular machine before; so they want to
* type a username, and then _either_ their key will be
* accepted, _or_ they will type a password. If they mistype
* the username they will want to be able to get back and
* retype it!
*/
s->username[0] = '\0';
s->got_username = FALSE;
do {
/*
* Get a username.
*/
if (s->got_username && !ssh->cfg.change_username) {
/*
* We got a username last time round this loop, and
* with change_username turned off we don't try to get
* it again.
*/
} else if (!*ssh->cfg.username) {
if (ssh_get_line && !ssh_getline_pw_only) {
if (!ssh_get_line("login as: ",
s->username, sizeof(s->username), FALSE)) {
/*
* get_line failed to get a username.
* Terminate.
*/
logevent("No username provided. Abandoning session.");
ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStopV;
}
} else {
int ret; /* need not be saved across crReturn */
c_write_str(ssh, "login as: ");
ssh->send_ok = 1;
setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
do {
crWaitUntilV(!pktin);
ret = process_userpass_input(ssh, in, inlen);
} while (ret == 0);
if (ret < 0)
cleanup_exit(0);
c_write_str(ssh, "\r\n");
}
s->username[strcspn(s->username, "\n\r")] = '\0';
} else {
char *stuff;
strncpy(s->username, ssh->cfg.username, sizeof(s->username));
s->username[sizeof(s->username)-1] = '\0';
if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
stuff = dupprintf("Using username \"%s\".\r\n", s->username);
c_write_str(ssh, stuff);
sfree(stuff);
}
}
s->got_username = TRUE;
/*
* Send an authentication request using method "none": (a)
* just in case it succeeds, and (b) so that we know what
* authentication methods we can usefully try next.
*/
ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(s->pktout, s->username);
ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */
ssh2_pkt_addstring(s->pktout, "none"); /* method */
ssh2_pkt_send(ssh, s->pktout);
s->type = AUTH_TYPE_NONE;
s->gotit = FALSE;
s->we_are_in = FALSE;
s->tried_pubkey_config = FALSE;
s->tried_agent = FALSE;
s->kbd_inter_running = FALSE;
s->kbd_inter_refused = FALSE;
/* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
if (!filename_is_null(ssh->cfg.keyfile)) {
int keytype;
logeventf(ssh, "Reading private key file \"%.150s\"",
filename_to_str(&ssh->cfg.keyfile));
keytype = key_type(&ssh->cfg.keyfile);
if (keytype == SSH_KEYTYPE_SSH2) {
s->publickey_blob =
ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
&s->publickey_bloblen, NULL);
} else {
char *msgbuf;
logeventf(ssh, "Unable to use this key file (%s)",
key_type_to_str(keytype));
msgbuf = dupprintf("Unable to use key file \"%.150s\""
" (%s)\r\n",
filename_to_str(&ssh->cfg.keyfile),
key_type_to_str(keytype));
c_write_str(ssh, msgbuf);
sfree(msgbuf);
s->publickey_blob = NULL;
}
} else
s->publickey_blob = NULL;
while (1) {
/*
* Wait for the result of the last authentication request.
*/
if (!s->gotit)
crWaitUntilV(pktin);
while (pktin->type == SSH2_MSG_USERAUTH_BANNER) {
char *banner;
int size;
/*
* Don't show the banner if we're operating in
* non-verbose non-interactive mode. (It's probably
* a script, which means nobody will read the
* banner _anyway_, and moreover the printing of
* the banner will screw up processing on the
* output of (say) plink.)
*/
if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
ssh_pkt_getstring(pktin, &banner, &size);
if (banner)
c_write_untrusted(ssh, banner, size);
}
crWaitUntilV(pktin);
}
if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
logevent("Access granted");
s->we_are_in = TRUE;
break;
}
if (s->kbd_inter_running &&
pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
/*
* This is either a further set-of-prompts packet
* in keyboard-interactive authentication, or it's
* the same one and we came back here with `gotit'
* set. In the former case, we must reset the
* curr_prompt variable.
*/
if (!s->gotit)
s->curr_prompt = 0;
} else if (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
/* FIXME: perhaps we should support this? */
bombout(("PASSWD_CHANGEREQ not yet supported"));
crStopV;
} else if (pktin->type != SSH2_MSG_USERAUTH_FAILURE) {
bombout(("Strange packet received during authentication: type %d",
pktin->type));
crStopV;
}
s->gotit = FALSE;
/*
* OK, we're now sitting on a USERAUTH_FAILURE message, so
* we can look at the string in it and know what we can
* helpfully try next.
*/
if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
char *methods;
int methlen;
ssh_pkt_getstring(pktin, &methods, &methlen);
s->kbd_inter_running = FALSE;
if (!ssh2_pkt_getbool(pktin)) {
/*
* We have received an unequivocal Access
* Denied. This can translate to a variety of
* messages:
*
* - if we'd just tried "none" authentication,
* it's not worth printing anything at all
*
* - if we'd just tried a public key _offer_,
* the message should be "Server refused our
* key" (or no message at all if the key
* came from Pageant)
*
* - if we'd just tried anything else, the
* message really should be "Access denied".
*
* Additionally, if we'd just tried password
* authentication, we should break out of this
* whole loop so as to go back to the username
* prompt (iff we're configured to allow
* username change attempts).
*/
if (s->type == AUTH_TYPE_NONE) {
/* do nothing */
} else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
c_write_str(ssh, "Server refused our key\r\n");
logevent("Server refused public key");
} else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
/* server declined keyboard-interactive; ignore */
} else {
c_write_str(ssh, "Access denied\r\n");
logevent("Access denied");
if (s->type == AUTH_TYPE_PASSWORD &&
ssh->cfg.change_username) {
/* XXX perhaps we should allow
* keyboard-interactive to do this too? */
s->we_are_in = FALSE;
break;
}
}
} else {
c_write_str(ssh, "Further authentication required\r\n");
logevent("Further authentication required");
}
s->can_pubkey =
in_commasep_string("publickey", methods, methlen);
s->can_passwd =
in_commasep_string("password", methods, methlen);
s->can_keyb_inter = ssh->cfg.try_ki_auth &&
in_commasep_string("keyboard-interactive", methods, methlen);
}
s->method = 0;
ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
s->need_pw = FALSE;
/*
* Most password/passphrase prompts will be
* non-echoing, so we set this to 0 by default.
* Exception is that some keyboard-interactive prompts
* can be echoing, in which case we'll set this to 1.
*/
s->echo = 0;
if (!s->method && s->can_pubkey &&
agent_exists() && !s->tried_agent) {
/*
* Attempt public-key authentication using Pageant.
*/
void *r;
s->authed = FALSE;
ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
s->tried_agent = TRUE;
logevent("Pageant is running. Requesting keys.");
/* Request the keys held by the agent. */
PUT_32BIT(s->request, 1);
s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
if (!agent_query(s->request, 5, &r, &s->responselen,
ssh_agent_callback, ssh)) {
do {
crReturnV;
if (pktin) {
bombout(("Unexpected data from server while"
" waiting for agent response"));
crStopV;
}
} while (pktin || inlen > 0);
r = ssh->agent_response;
s->responselen = ssh->agent_response_len;
}
s->response = (unsigned char *) r;
if (s->response && s->responselen >= 5 &&
s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
s->p = s->response + 5;
s->nkeys = GET_32BIT(s->p);
s->p += 4;
logeventf(ssh, "Pageant has %d SSH2 keys", s->nkeys);
for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
void *vret;
logeventf(ssh, "Trying Pageant key #%d", s->keyi);
s->pklen = GET_32BIT(s->p);
s->p += 4;
if (s->publickey_blob &&
s->pklen == s->publickey_bloblen &&
!memcmp(s->p, s->publickey_blob,
s->publickey_bloblen)) {
logevent("This key matches configured key file");
s->tried_pubkey_config = 1;
}
s->pkblob = (char *)s->p;
s->p += s->pklen;
s->alglen = GET_32BIT(s->pkblob);
s->alg = s->pkblob + 4;
s->commentlen = GET_32BIT(s->p);
s->p += 4;
s->commentp = (char *)s->p;
s->p += s->commentlen;
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(s->pktout, s->username);
ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */
ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
ssh2_pkt_addstring_start(s->pktout);
ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
ssh2_pkt_addstring_start(s->pktout);
ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
ssh2_pkt_send(ssh, s->pktout);
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
logevent("Key refused");
continue;
}
if (flags & FLAG_VERBOSE) {
c_write_str(ssh, "Authenticating with "
"public key \"");
c_write(ssh, s->commentp, s->commentlen);
c_write_str(ssh, "\" from agent\r\n");
}
/*
* Server is willing to accept the key.
* Construct a SIGN_REQUEST.
*/
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(s->pktout, s->username);
ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */
ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
ssh2_pkt_addbool(s->pktout, TRUE);
ssh2_pkt_addstring_start(s->pktout);
ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
ssh2_pkt_addstring_start(s->pktout);
ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
s->siglen = s->pktout->length - 5 + 4 + 20;
if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
s->siglen -= 4;
s->len = 1; /* message type */
s->len += 4 + s->pklen; /* key blob */
s->len += 4 + s->siglen; /* data to sign */
s->len += 4; /* flags */
s->agentreq = snewn(4 + s->len, char);
PUT_32BIT(s->agentreq, s->len);
s->q = s->agentreq + 4;
*s->q++ = SSH2_AGENTC_SIGN_REQUEST;
PUT_32BIT(s->q, s->pklen);
s->q += 4;
memcpy(s->q, s->pkblob, s->pklen);
s->q += s->pklen;
PUT_32BIT(s->q, s->siglen);
s->q += 4;
/* Now the data to be signed... */
if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
PUT_32BIT(s->q, 20);
s->q += 4;
}
memcpy(s->q, ssh->v2_session_id, 20);
s->q += 20;
memcpy(s->q, s->pktout->data + 5,
s->pktout->length - 5);
s->q += s->pktout->length - 5;
/* And finally the (zero) flags word. */
PUT_32BIT(s->q, 0);
if (!agent_query(s->agentreq, s->len + 4,
&vret, &s->retlen,
ssh_agent_callback, ssh)) {
do {
crReturnV;
if (pktin) {
bombout(("Unexpected data from server"
" while waiting for agent"
" response"));
crStopV;
}
} while (pktin || inlen > 0);
vret = ssh->agent_response;
s->retlen = ssh->agent_response_len;
}
s->ret = vret;
sfree(s->agentreq);
if (s->ret) {
if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
logevent("Sending Pageant's response");
ssh2_add_sigblob(ssh, s->pktout,
s->pkblob, s->pklen,
s->ret + 9,
GET_32BIT(s->ret + 5));
ssh2_pkt_send(ssh, s->pktout);
s->authed = TRUE;
break;
} else {
logevent
("Pageant failed to answer challenge");
sfree(s->ret);
}
}
}
if (s->authed)
continue;
}
sfree(s->response);
}
if (!s->method && s->can_pubkey && s->publickey_blob
&& !s->tried_pubkey_config) {
unsigned char *pub_blob;
char *algorithm, *comment;
int pub_blob_len;
s->tried_pubkey_config = TRUE;
ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
/*
* Try the public key supplied in the configuration.
*
* First, offer the public blob to see if the server is
* willing to accept it.
*/
pub_blob =
(unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
&algorithm,
&pub_blob_len,
NULL);
if (pub_blob) {
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(s->pktout, s->username);
ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */
ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
ssh2_pkt_addstring(s->pktout, algorithm);
ssh2_pkt_addstring_start(s->pktout);
ssh2_pkt_addstring_data(s->pktout, (char *)pub_blob,
pub_blob_len);
ssh2_pkt_send(ssh, s->pktout);
logevent("Offered public key");
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
s->gotit = TRUE;
s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
continue; /* key refused; give up on it */
}
logevent("Offer of public key accepted");
/*
* Actually attempt a serious authentication using
* the key.
*/
if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
sprintf(s->pwprompt,
"Passphrase for key \"%.100s\": ",
comment);
s->need_pw = TRUE;
} else {
s->need_pw = FALSE;
}
if (flags & FLAG_VERBOSE) {
c_write_str(ssh, "Authenticating with public key \"");
c_write_str(ssh, comment);
c_write_str(ssh, "\"\r\n");
}
s->method = AUTH_PUBLICKEY_FILE;
}
}
if (!s->method && s->can_keyb_inter && !s->kbd_inter_refused &&
!s->kbd_inter_running) {
s->method = AUTH_KEYBOARD_INTERACTIVE;
s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(s->pktout, s->username);
ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */
ssh2_pkt_addstring(s->pktout, "keyboard-interactive"); /* method */
ssh2_pkt_addstring(s->pktout, ""); /* lang */
ssh2_pkt_addstring(s->pktout, "");
ssh2_pkt_send(ssh, s->pktout);
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
if (pktin->type == SSH2_MSG_USERAUTH_FAILURE)
s->gotit = TRUE;
logevent("Keyboard-interactive authentication refused");
s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
s->kbd_inter_refused = TRUE; /* don't try it again */
continue;
}
s->kbd_inter_running = TRUE;
s->curr_prompt = 0;
}
if (s->kbd_inter_running) {
s->method = AUTH_KEYBOARD_INTERACTIVE;
s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
if (s->curr_prompt == 0) {
/*
* We've got a fresh USERAUTH_INFO_REQUEST.
* Display header data, and start going through
* the prompts.
*/
char *name, *inst, *lang;
int name_len, inst_len, lang_len;
ssh_pkt_getstring(pktin, &name, &name_len);
ssh_pkt_getstring(pktin, &inst, &inst_len);
ssh_pkt_getstring(pktin, &lang, &lang_len);
if (name_len > 0) {
c_write_untrusted(ssh, name, name_len);
c_write_str(ssh, "\r\n");
}
if (inst_len > 0) {
c_write_untrusted(ssh, inst, inst_len);
c_write_str(ssh, "\r\n");
}
s->num_prompts = ssh_pkt_getuint32(pktin);
}
/*
* If there are prompts remaining in the packet,
* display one and get a response.
*/
if (s->curr_prompt < s->num_prompts) {
char *prompt;
int prompt_len;
ssh_pkt_getstring(pktin, &prompt, &prompt_len);
if (prompt_len > 0) {
static const char trunc[] = "<prompt truncated>: ";
static const int prlen = sizeof(s->pwprompt) -
lenof(trunc);
if (prompt_len > prlen) {
memcpy(s->pwprompt, prompt, prlen);
strcpy(s->pwprompt + prlen, trunc);
} else {
memcpy(s->pwprompt, prompt, prompt_len);
s->pwprompt[prompt_len] = '\0';
}
} else {
strcpy(s->pwprompt,
"<server failed to send prompt>: ");
}
s->echo = ssh2_pkt_getbool(pktin);
s->need_pw = TRUE;
} else
s->need_pw = FALSE;
}
if (!s->method && s->can_passwd) {
s->method = AUTH_PASSWORD;
ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
ssh->savedhost);
s->need_pw = TRUE;
}
if (s->need_pw) {
if (ssh_get_line) {
if (!ssh_get_line(s->pwprompt, s->password,
sizeof(s->password), TRUE)) {
/*
* get_line failed to get a password (for
* example because one was supplied on the
* command line which has already failed to
* work). Terminate.
*/
s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
ssh2_pkt_adduint32(s->pktout,SSH2_DISCONNECT_BY_APPLICATION);
ssh2_pkt_addstring(s->pktout, "No more passwords available"
" to try");
ssh2_pkt_addstring(s->pktout, "en"); /* language tag */
ssh2_pkt_send_noqueue(ssh, s->pktout);
logevent("Unable to authenticate");
connection_fatal(ssh->frontend,
"Unable to authenticate");
ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStopV;
}
} else {
int ret; /* need not be saved across crReturn */
c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
ssh->send_ok = 1;
setup_userpass_input(ssh, s->password,
sizeof(s->password), s->echo);
do {
crWaitUntilV(!pktin);
ret = process_userpass_input(ssh, in, inlen);
} while (ret == 0);
if (ret < 0)
cleanup_exit(0);
c_write_str(ssh, "\r\n");
}
}
if (s->method == AUTH_PUBLICKEY_FILE) {
/*
* We have our passphrase. Now try the actual authentication.
*/
struct ssh2_userkey *key;
const char *error = NULL;
key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
&error);
if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
if (key == SSH2_WRONG_PASSPHRASE) {
c_write_str(ssh, "Wrong passphrase\r\n");
s->tried_pubkey_config = FALSE;
} else {
c_write_str(ssh, "Unable to load private key (");
c_write_str(ssh, error);
c_write_str(ssh, ")\r\n");
s->tried_pubkey_config = TRUE;
}
/* Send a spurious AUTH_NONE to return to the top. */
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(s->pktout, s->username);
ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */
ssh2_pkt_addstring(s->pktout, "none"); /* method */
ssh2_pkt_send(ssh, s->pktout);
s->type = AUTH_TYPE_NONE;
} else {
unsigned char *pkblob, *sigblob, *sigdata;
int pkblob_len, sigblob_len, sigdata_len;
int p;
/*
* We have loaded the private key and the server
* has announced that it's willing to accept it.
* Hallelujah. Generate a signature and send it.
*/
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(s->pktout, s->username);
ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */
ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
ssh2_pkt_addbool(s->pktout, TRUE);
ssh2_pkt_addstring(s->pktout, key->alg->name);
pkblob = key->alg->public_blob(key->data, &pkblob_len);
ssh2_pkt_addstring_start(s->pktout);
ssh2_pkt_addstring_data(s->pktout, (char *)pkblob, pkblob_len);
/*
* The data to be signed is:
*
* string session-id
*
* followed by everything so far placed in the
* outgoing packet.
*/
sigdata_len = s->pktout->length - 5 + 4 + 20;
if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
sigdata_len -= 4;
sigdata = snewn(sigdata_len, unsigned char);
p = 0;
if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
PUT_32BIT(sigdata+p, 20);
p += 4;
}
memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
memcpy(sigdata+p, s->pktout->data + 5,
s->pktout->length - 5);
p += s->pktout->length - 5;
assert(p == sigdata_len);
sigblob = key->alg->sign(key->data, (char *)sigdata,
sigdata_len, &sigblob_len);
ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
sigblob, sigblob_len);
sfree(pkblob);
sfree(sigblob);
sfree(sigdata);
ssh2_pkt_send(ssh, s->pktout);
s->type = AUTH_TYPE_PUBLICKEY;
key->alg->freekey(key->data);
}
} else if (s->method == AUTH_PASSWORD) {
/*
* We pad out the password packet to 256 bytes to make
* it harder for an attacker to find the length of the
* user's password.
*
* Anyone using a password longer than 256 bytes
* probably doesn't have much to worry about from
* people who find out how long their password is!
*/
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
s->pktout->forcepad = 256;
ssh2_pkt_addstring(s->pktout, s->username);
ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */
ssh2_pkt_addstring(s->pktout, "password");
ssh2_pkt_addbool(s->pktout, FALSE);
dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
ssh2_pkt_addstring(s->pktout, s->password);
memset(s->password, 0, sizeof(s->password));
end_log_omission(ssh, s->pktout);
ssh2_pkt_send(ssh, s->pktout);
logevent("Sent password");
s->type = AUTH_TYPE_PASSWORD;
} else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
if (s->curr_prompt == 0) {
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
s->pktout->forcepad = 256;
ssh2_pkt_adduint32(s->pktout, s->num_prompts);
}
if (s->need_pw) { /* only add pw if we just got one! */
dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
ssh2_pkt_addstring(s->pktout, s->password);
memset(s->password, 0, sizeof(s->password));
end_log_omission(ssh, s->pktout);
s->curr_prompt++;
}
if (s->curr_prompt >= s->num_prompts) {
ssh2_pkt_send(ssh, s->pktout);
} else {
/*
* If there are prompts remaining, we set
* `gotit' so that we won't attempt to get
* another packet. Then we go back round the
* loop and will end up retrieving another
* prompt out of the existing packet. Funky or
* what?
*/
s->gotit = TRUE;
}
s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
} else {
c_write_str(ssh, "No supported authentication methods"
" left to try!\r\n");
logevent("No supported authentications offered."
" Disconnecting");
s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
ssh2_pkt_adduint32(s->pktout, SSH2_DISCONNECT_BY_APPLICATION);
ssh2_pkt_addstring(s->pktout, "No supported authentication"
" methods available");
ssh2_pkt_addstring(s->pktout, "en"); /* language tag */
ssh2_pkt_send_noqueue(ssh, s->pktout);
ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStopV;
}
}
} while (!s->we_are_in);
/*
* Now we're authenticated for the connection protocol. The
* connection protocol will automatically have started at this
* point; there's no need to send SERVICE_REQUEST.
*/
ssh->channels = newtree234(ssh_channelcmp);
/*
* Set up handlers for some connection protocol messages, so we
* don't have to handle them repeatedly in this coroutine.
*/
ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] =
ssh2_msg_channel_window_adjust;
ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] =
ssh2_msg_global_request;
/*
* Create the main session channel.
*/
if (!ssh->cfg.ssh_no_shell) {
ssh->mainchan = snew(struct ssh_channel);
ssh->mainchan->ssh = ssh;
ssh->mainchan->localid = alloc_channel_id(ssh);
s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
ssh2_pkt_addstring(s->pktout, "session");
ssh2_pkt_adduint32(s->pktout, ssh->mainchan->localid);
ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
ssh2_pkt_adduint32(s->pktout, ssh->mainchan->v.v2.locwindow);/* our window size */
ssh2_pkt_adduint32(s->pktout, OUR_V2_MAXPKT); /* our max pkt size */
ssh2_pkt_send(ssh, s->pktout);
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
bombout(("Server refused to open a session"));
crStopV;
/* FIXME: error data comes back in FAILURE packet */
}
if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
bombout(("Server's channel confirmation cited wrong channel"));
crStopV;
}
ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
ssh->mainchan->halfopen = FALSE;
ssh->mainchan->type = CHAN_MAINSESSION;
ssh->mainchan->closes = 0;
ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
bufchain_init(&ssh->mainchan->v.v2.outbuffer);
add234(ssh->channels, ssh->mainchan);
update_specials_menu(ssh->frontend);
logevent("Opened channel for session");
} else
ssh->mainchan = NULL;
/*
* Now we have a channel, make dispatch table entries for
* general channel-based messages.
*/
ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] =
ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] =
ssh2_msg_channel_data;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_channel_eof;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_channel_close;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] =
ssh2_msg_channel_open_confirmation;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] =
ssh2_msg_channel_open_failure;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] =
ssh2_msg_channel_request;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
ssh2_msg_channel_open;
/*
* Potentially enable X11 forwarding.
*/
if (ssh->mainchan && ssh->cfg.x11_forward) {
char proto[20], data[64];
logevent("Requesting X11 forwarding");
ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
data, sizeof(data), ssh->cfg.x11_auth);
x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
ssh2_pkt_addstring(s->pktout, "x11-req");
ssh2_pkt_addbool(s->pktout, 1); /* want reply */
ssh2_pkt_addbool(s->pktout, 0); /* many connections */
ssh2_pkt_addstring(s->pktout, proto);
ssh2_pkt_addstring(s->pktout, data);
ssh2_pkt_adduint32(s->pktout, x11_get_screen_number(ssh->cfg.x11_display));
ssh2_pkt_send(ssh, s->pktout);
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Unexpected response to X11 forwarding request:"
" packet type %d", pktin->type));
crStopV;
}
logevent("X11 forwarding refused");
} else {
logevent("X11 forwarding enabled");
ssh->X11_fwd_enabled = TRUE;
}
}
/*
* Enable port forwardings.
*/
ssh_setup_portfwd(ssh, &ssh->cfg);
/*
* Potentially enable agent forwarding.
*/
if (ssh->mainchan && ssh->cfg.agentfwd && agent_exists()) {
logevent("Requesting OpenSSH-style agent forwarding");
s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
ssh2_pkt_addstring(s->pktout, "auth-agent-req@openssh.com");
ssh2_pkt_addbool(s->pktout, 1); /* want reply */
ssh2_pkt_send(ssh, s->pktout);
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Unexpected response to agent forwarding request:"
" packet type %d", pktin->type));
crStopV;
}
logevent("Agent forwarding refused");
} else {
logevent("Agent forwarding enabled");
ssh->agentfwd_enabled = TRUE;
}
}
/*
* Now allocate a pty for the session.
*/
if (ssh->mainchan && !ssh->cfg.nopty) {
/* Unpick the terminal-speed string. */
/* XXX perhaps we should allow no speeds to be sent. */
ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
/* Build the pty request. */
s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid); /* recipient channel */
ssh2_pkt_addstring(s->pktout, "pty-req");
ssh2_pkt_addbool(s->pktout, 1); /* want reply */
ssh2_pkt_addstring(s->pktout, ssh->cfg.termtype);
ssh2_pkt_adduint32(s->pktout, ssh->term_width);
ssh2_pkt_adduint32(s->pktout, ssh->term_height);
ssh2_pkt_adduint32(s->pktout, 0); /* pixel width */
ssh2_pkt_adduint32(s->pktout, 0); /* pixel height */
ssh2_pkt_addstring_start(s->pktout);
ssh2_pkt_addbyte(s->pktout, 128); /* TTY_OP_ISPEED */
ssh2_pkt_adduint32(s->pktout, ssh->ispeed);
ssh2_pkt_addbyte(s->pktout, 129); /* TTY_OP_OSPEED */
ssh2_pkt_adduint32(s->pktout, ssh->ospeed);
ssh2_pkt_addstring_data(s->pktout, "\0", 1); /* TTY_OP_END */
ssh2_pkt_send(ssh, s->pktout);
ssh->state = SSH_STATE_INTERMED;
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Unexpected response to pty request:"
" packet type %d", pktin->type));
crStopV;
}
c_write_str(ssh, "Server refused to allocate pty\r\n");
ssh->editing = ssh->echoing = 1;
} else {
logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
ssh->ospeed, ssh->ispeed);
}
} else {
ssh->editing = ssh->echoing = 1;
}
/*
* Send environment variables.
*
* Simplest thing here is to send all the requests at once, and
* then wait for a whole bunch of successes or failures.
*/
if (ssh->mainchan && *ssh->cfg.environmt) {
char *e = ssh->cfg.environmt;
char *var, *varend, *val;
s->num_env = 0;
while (*e) {
var = e;
while (*e && *e != '\t') e++;
varend = e;
if (*e == '\t') e++;
val = e;
while (*e) e++;
e++;
s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
ssh2_pkt_addstring(s->pktout, "env");
ssh2_pkt_addbool(s->pktout, 1); /* want reply */
ssh2_pkt_addstring_start(s->pktout);
ssh2_pkt_addstring_data(s->pktout, var, varend-var);
ssh2_pkt_addstring(s->pktout, val);
ssh2_pkt_send(ssh, s->pktout);
s->num_env++;
}
logeventf(ssh, "Sent %d environment variables", s->num_env);
s->env_ok = 0;
s->env_left = s->num_env;
while (s->env_left > 0) {
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Unexpected response to environment request:"
" packet type %d", pktin->type));
crStopV;
}
} else {
s->env_ok++;
}
s->env_left--;
}
if (s->env_ok == s->num_env) {
logevent("All environment variables successfully set");
} else if (s->env_ok == 0) {
logevent("All environment variables refused");
c_write_str(ssh, "Server refused to set environment variables\r\n");
} else {
logeventf(ssh, "%d environment variables refused",
s->num_env - s->env_ok);
c_write_str(ssh, "Server refused to set all environment variables\r\n");
}
}
/*
* Start a shell or a remote command. We may have to attempt
* this twice if the config data has provided a second choice
* of command.
*/
if (ssh->mainchan) while (1) {
int subsys;
char *cmd;
if (ssh->fallback_cmd) {
subsys = ssh->cfg.ssh_subsys2;
cmd = ssh->cfg.remote_cmd_ptr2;
} else {
subsys = ssh->cfg.ssh_subsys;
cmd = ssh->cfg.remote_cmd_ptr;
}
s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid); /* recipient channel */
if (subsys) {
ssh2_pkt_addstring(s->pktout, "subsystem");
ssh2_pkt_addbool(s->pktout, 1); /* want reply */
ssh2_pkt_addstring(s->pktout, cmd);
} else if (*cmd) {
ssh2_pkt_addstring(s->pktout, "exec");
ssh2_pkt_addbool(s->pktout, 1); /* want reply */
ssh2_pkt_addstring(s->pktout, cmd);
} else {
ssh2_pkt_addstring(s->pktout, "shell");
ssh2_pkt_addbool(s->pktout, 1); /* want reply */
}
ssh2_pkt_send(ssh, s->pktout);
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Unexpected response to shell/command request:"
" packet type %d", pktin->type));
crStopV;
}
/*
* We failed to start the command. If this is the
* fallback command, we really are finished; if it's
* not, and if the fallback command exists, try falling
* back to it before complaining.
*/
if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
logevent("Primary command failed; attempting fallback");
ssh->fallback_cmd = TRUE;
continue;
}
bombout(("Server refused to start a shell/command"));
crStopV;
} else {
logevent("Started a shell/command");
}
break;
}
ssh->state = SSH_STATE_SESSION;
if (ssh->size_needed)
ssh_size(ssh, ssh->term_width, ssh->term_height);
if (ssh->eof_needed)
ssh_special(ssh, TS_EOF);
/*
* Transfer data!
*/
if (ssh->ldisc)
ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
if (ssh->mainchan)
ssh->send_ok = 1;
while (1) {
crReturnV;
s->try_send = FALSE;
if (pktin) {
/*
* _All_ the connection-layer packets we expect to
* receive are now handled by the dispatch table.
* Anything that reaches here must be bogus.
*/
bombout(("Strange packet received: type %d", pktin->type));
crStopV;
} else if (ssh->mainchan) {
/*
* We have spare data. Add it to the channel buffer.
*/
ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
s->try_send = TRUE;
}
if (s->try_send) {
int i;
struct ssh_channel *c;
/*
* Try to send data on all channels if we can.
*/
for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
int bufsize;
if (c->closes)
continue; /* don't send on closing channels */
bufsize = ssh2_try_send(c);
if (bufsize == 0) {
switch (c->type) {
case CHAN_MAINSESSION:
/* stdin need not receive an unthrottle
* notification since it will be polled */
break;
case CHAN_X11:
x11_unthrottle(c->u.x11.s);
break;
case CHAN_AGENT:
/* agent sockets are request/response and need no
* buffer management */
break;
case CHAN_SOCKDATA:
pfd_unthrottle(c->u.pfd.s);
break;
}
}
}
}
}
crFinishV;
}
/*
* Handlers for SSH2 messages that might arrive at any moment.
*/
static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
{
/* log reason code in disconnect message */
char *buf, *msg;
int nowlen, reason, msglen;
reason = ssh_pkt_getuint32(pktin);
ssh_pkt_getstring(pktin, &msg, &msglen);
if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
buf = dupprintf("Received disconnect message (%s)",
ssh2_disconnect_reasons[reason]);
} else {
buf = dupprintf("Received disconnect message (unknown"
" type %d)", reason);
}
logevent(buf);
sfree(buf);
buf = dupprintf("Disconnection message text: %n%.*s",
&nowlen, msglen, msg);
logevent(buf);
bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
reason,
(reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
ssh2_disconnect_reasons[reason] : "unknown",
buf+nowlen));
sfree(buf);
}
static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
{
/* log the debug message */
char *msg;
int msglen;
int always_display;
/* XXX maybe we should actually take notice of this */
always_display = ssh2_pkt_getbool(pktin);
ssh_pkt_getstring(pktin, &msg, &msglen);
logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
}
static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
{
struct Packet *pktout;
pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED);
ssh2_pkt_adduint32(pktout, pktin->sequence);
/*
* UNIMPLEMENTED messages MUST appear in the same order as the
* messages they respond to. Hence, never queue them.
*/
ssh2_pkt_send_noqueue(ssh, pktout);
}
/*
* Handle the top-level SSH2 protocol.
*/
static void ssh2_protocol_setup(Ssh ssh)
{
int i;
/*
* Most messages cause SSH2_MSG_UNIMPLEMENTED.
*/
for (i = 0; i < 256; i++)
ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
/*
* Any message we actually understand, we set to NULL so that
* the coroutines will get it.
*/
ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = NULL;
ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = NULL;
ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = NULL;
ssh->packet_dispatch[SSH2_MSG_KEXINIT] = NULL;
ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = NULL;
ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = NULL;
ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = NULL;
/* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = NULL; duplicate case value */
/* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = NULL; duplicate case value */
ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = NULL;
ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = NULL;
ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = NULL;
ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = NULL;
ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = NULL;
ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = NULL;
/* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = NULL; duplicate case value */
/* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = NULL; duplicate case value */
ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = NULL;
ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = NULL;
ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = NULL;
ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = NULL;
ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = NULL;
/*
* These special message types we install handlers for.
*/
ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with ssh1 */
ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
}
static void ssh2_timer(void *ctx, long now)
{
Ssh ssh = (Ssh)ctx;
if (!ssh->kex_in_progress && ssh->cfg.ssh_rekey_time != 0 &&
now - ssh->next_rekey >= 0) {
do_ssh2_transport(ssh, "timeout", -1, NULL);
}
}
static void ssh2_protocol(Ssh ssh, void *vin, int inlen,
struct Packet *pktin)
{
unsigned char *in = (unsigned char *)vin;
if (ssh->state == SSH_STATE_CLOSED)
return;
if (pktin) {
ssh->incoming_data_size += pktin->encrypted_len;
if (!ssh->kex_in_progress &&
ssh->max_data_size != 0 &&
ssh->incoming_data_size > ssh->max_data_size)
do_ssh2_transport(ssh, "too much data received", -1, NULL);
}
if (pktin && ssh->packet_dispatch[pktin->type]) {
ssh->packet_dispatch[pktin->type](ssh, pktin);
return;
}
if (!ssh->protocol_initial_phase_done ||
(pktin && pktin->type >= 20 && pktin->type < 50)) {
if (do_ssh2_transport(ssh, in, inlen, pktin) &&
!ssh->protocol_initial_phase_done) {
ssh->protocol_initial_phase_done = TRUE;
/*
* Allow authconn to initialise itself.
*/
do_ssh2_authconn(ssh, NULL, 0, NULL);
}
} else {
do_ssh2_authconn(ssh, in, inlen, pktin);
}
}
/*
* Called to set up the connection.
*
* Returns an error message, or NULL on success.
*/
static const char *ssh_init(void *frontend_handle, void **backend_handle,
Config *cfg,
char *host, int port, char **realhost, int nodelay,
int keepalive)
{
const char *p;
Ssh ssh;
ssh = snew(struct ssh_tag);
ssh->cfg = *cfg; /* STRUCTURE COPY */
ssh->version = 0; /* when not ready yet */
ssh->s = NULL;
ssh->cipher = NULL;
ssh->v1_cipher_ctx = NULL;
ssh->crcda_ctx = NULL;
ssh->cscipher = NULL;
ssh->cs_cipher_ctx = NULL;
ssh->sccipher = NULL;
ssh->sc_cipher_ctx = NULL;
ssh->csmac = NULL;
ssh->cs_mac_ctx = NULL;
ssh->scmac = NULL;
ssh->sc_mac_ctx = NULL;
ssh->cscomp = NULL;
ssh->cs_comp_ctx = NULL;
ssh->sccomp = NULL;
ssh->sc_comp_ctx = NULL;
ssh->kex = NULL;
ssh->kex_ctx = NULL;
ssh->hostkey = NULL;
ssh->exitcode = -1;
ssh->close_expected = FALSE;
ssh->state = SSH_STATE_PREPACKET;
ssh->size_needed = FALSE;
ssh->eof_needed = FALSE;
ssh->ldisc = NULL;
ssh->logctx = NULL;
ssh->deferred_send_data = NULL;
ssh->deferred_len = 0;
ssh->deferred_size = 0;
ssh->fallback_cmd = 0;
ssh->pkt_ctx = 0;
ssh->x11auth = NULL;
ssh->v1_compressing = FALSE;
ssh->v2_outgoing_sequence = 0;
ssh->ssh1_rdpkt_crstate = 0;
ssh->ssh2_rdpkt_crstate = 0;
ssh->do_ssh_init_crstate = 0;
ssh->ssh_gotdata_crstate = 0;
ssh->do_ssh1_connection_crstate = 0;
ssh->do_ssh1_login_crstate = 0;
ssh->do_ssh2_transport_crstate = 0;
ssh->do_ssh2_authconn_crstate = 0;
ssh->do_ssh_init_state = NULL;
ssh->do_ssh1_login_state = NULL;
ssh->do_ssh2_transport_state = NULL;
ssh->do_ssh2_authconn_state = NULL;
ssh->mainchan = NULL;
ssh->throttled_all = 0;
ssh->v1_stdout_throttling = 0;
ssh->queue = NULL;
ssh->queuelen = ssh->queuesize = 0;
ssh->queueing = FALSE;
ssh->qhead = ssh->qtail = NULL;
ssh->deferred_rekey_reason = NULL;
*backend_handle = ssh;
#ifdef MSCRYPTOAPI
if (crypto_startup() == 0)
return "Microsoft high encryption pack not installed!";
#endif
ssh->frontend = frontend_handle;
ssh->term_width = ssh->cfg.width;
ssh->term_height = ssh->cfg.height;
ssh->channels = NULL;
ssh->rportfwds = NULL;
ssh->portfwds = NULL;
ssh->send_ok = 0;
ssh->editing = 0;
ssh->echoing = 0;
ssh->v1_throttle_count = 0;
ssh->overall_bufsize = 0;
ssh->fallback_cmd = 0;
ssh->protocol = NULL;
ssh->protocol_initial_phase_done = FALSE;
ssh->pinger = NULL;
ssh->incoming_data_size = ssh->outgoing_data_size =
ssh->deferred_data_size = 0L;
ssh->max_data_size = parse_blocksize(ssh->cfg.ssh_rekey_data);
ssh->kex_in_progress = FALSE;
p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
if (p != NULL)
return p;
random_ref();
return NULL;
}
static void ssh_free(void *handle)
{
Ssh ssh = (Ssh) handle;
struct ssh_channel *c;
struct ssh_rportfwd *pf;
if (ssh->v1_cipher_ctx)
ssh->cipher->free_context(ssh->v1_cipher_ctx);
if (ssh->cs_cipher_ctx)
ssh->cscipher->free_context(ssh->cs_cipher_ctx);
if (ssh->sc_cipher_ctx)
ssh->sccipher->free_context(ssh->sc_cipher_ctx);
if (ssh->cs_mac_ctx)
ssh->csmac->free_context(ssh->cs_mac_ctx);
if (ssh->sc_mac_ctx)
ssh->scmac->free_context(ssh->sc_mac_ctx);
if (ssh->cs_comp_ctx) {
if (ssh->cscomp)
ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
else
zlib_compress_cleanup(ssh->cs_comp_ctx);
}
if (ssh->sc_comp_ctx) {
if (ssh->sccomp)
ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
else
zlib_decompress_cleanup(ssh->sc_comp_ctx);
}
if (ssh->kex_ctx)
dh_cleanup(ssh->kex_ctx);
sfree(ssh->savedhost);
while (ssh->queuelen-- > 0)
ssh_free_packet(ssh->queue[ssh->queuelen]);
sfree(ssh->queue);
while (ssh->qhead) {
struct queued_handler *qh = ssh->qhead;
ssh->qhead = qh->next;
sfree(ssh->qhead);
}
ssh->qhead = ssh->qtail = NULL;
if (ssh->channels) {
while ((c = delpos234(ssh->channels, 0)) != NULL) {
switch (c->type) {
case CHAN_X11:
if (c->u.x11.s != NULL)
x11_close(c->u.x11.s);
break;
case CHAN_SOCKDATA:
if (c->u.pfd.s != NULL)
pfd_close(c->u.pfd.s);
break;
}
sfree(c);
}
freetree234(ssh->channels);
ssh->channels = NULL;
}
if (ssh->rportfwds) {
while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
sfree(pf);
freetree234(ssh->rportfwds);
ssh->rportfwds = NULL;
}
sfree(ssh->deferred_send_data);
if (ssh->x11auth)
x11_free_auth(ssh->x11auth);
sfree(ssh->do_ssh_init_state);
sfree(ssh->do_ssh1_login_state);
sfree(ssh->do_ssh2_transport_state);
sfree(ssh->do_ssh2_authconn_state);
if (ssh->crcda_ctx) {
crcda_free_context(ssh->crcda_ctx);
ssh->crcda_ctx = NULL;
}
if (ssh->s)
ssh_do_close(ssh, TRUE);
expire_timer_context(ssh);
if (ssh->pinger)
pinger_free(ssh->pinger);
sfree(ssh);
random_unref();
}
/*
* Reconfigure the SSH backend.
*/
static void ssh_reconfig(void *handle, Config *cfg)
{
Ssh ssh = (Ssh) handle;
char *rekeying = NULL, rekey_mandatory = FALSE;
unsigned long old_max_data_size;
pinger_reconfig(ssh->pinger, &ssh->cfg, cfg);
ssh_setup_portfwd(ssh, cfg);
if (ssh->cfg.ssh_rekey_time != cfg->ssh_rekey_time &&
cfg->ssh_rekey_time != 0) {
long new_next = ssh->last_rekey + cfg->ssh_rekey_time*60*TICKSPERSEC;
long now = GETTICKCOUNT();
if (new_next - now < 0) {
rekeying = "timeout shortened";
} else {
ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh);
}
}
old_max_data_size = ssh->max_data_size;
ssh->max_data_size = parse_blocksize(cfg->ssh_rekey_data);
if (old_max_data_size != ssh->max_data_size &&
ssh->max_data_size != 0) {
if (ssh->outgoing_data_size > ssh->max_data_size ||
ssh->incoming_data_size > ssh->max_data_size)
rekeying = "data limit lowered";
}
if (ssh->cfg.compression != cfg->compression) {
rekeying = "compression setting changed";
rekey_mandatory = TRUE;
}
if (ssh->cfg.ssh2_des_cbc != cfg->ssh2_des_cbc ||
memcmp(ssh->cfg.ssh_cipherlist, cfg->ssh_cipherlist,
sizeof(ssh->cfg.ssh_cipherlist))) {
rekeying = "cipher settings changed";
rekey_mandatory = TRUE;
}
ssh->cfg = *cfg; /* STRUCTURE COPY */
if (rekeying) {
if (!ssh->kex_in_progress) {
do_ssh2_transport(ssh, rekeying, -1, NULL);
} else if (rekey_mandatory) {
ssh->deferred_rekey_reason = rekeying;
}
}
}
/*
* Called to send data down the Telnet connection.
*/
static int ssh_send(void *handle, char *buf, int len)
{
Ssh ssh = (Ssh) handle;
if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
return 0;
ssh->protocol(ssh, (unsigned char *)buf, len, 0);
return ssh_sendbuffer(ssh);
}
/*
* Called to query the current amount of buffered stdin data.
*/
static int ssh_sendbuffer(void *handle)
{
Ssh ssh = (Ssh) handle;
int override_value;
if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
return 0;
/*
* If the SSH socket itself has backed up, add the total backup
* size on that to any individual buffer on the stdin channel.
*/
override_value = 0;
if (ssh->throttled_all)
override_value = ssh->overall_bufsize;
if (ssh->version == 1) {
return override_value;
} else if (ssh->version == 2) {
if (!ssh->mainchan || ssh->mainchan->closes > 0)
return override_value;
else
return (override_value +
bufchain_size(&ssh->mainchan->v.v2.outbuffer));
}
return 0;
}
/*
* Called to set the size of the window from SSH's POV.
*/
static void ssh_size(void *handle, int width, int height)
{
Ssh ssh = (Ssh) handle;
struct Packet *pktout;
ssh->term_width = width;
ssh->term_height = height;
switch (ssh->state) {
case SSH_STATE_BEFORE_SIZE:
case SSH_STATE_PREPACKET:
case SSH_STATE_CLOSED:
break; /* do nothing */
case SSH_STATE_INTERMED:
ssh->size_needed = TRUE; /* buffer for later */
break;
case SSH_STATE_SESSION:
if (!ssh->cfg.nopty) {
if (ssh->version == 1) {
send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
PKT_INT, ssh->term_height,
PKT_INT, ssh->term_width,
PKT_INT, 0, PKT_INT, 0, PKT_END);
} else if (ssh->mainchan) {
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid);
ssh2_pkt_addstring(pktout, "window-change");
ssh2_pkt_addbool(pktout, 0);
ssh2_pkt_adduint32(pktout, ssh->term_width);
ssh2_pkt_adduint32(pktout, ssh->term_height);
ssh2_pkt_adduint32(pktout, 0);
ssh2_pkt_adduint32(pktout, 0);
ssh2_pkt_send(ssh, pktout);
}
}
break;
}
}
/*
* Return a list of the special codes that make sense in this
* protocol.
*/
static const struct telnet_special *ssh_get_specials(void *handle)
{
static const struct telnet_special ssh1_ignore_special[] = {
{"IGNORE message", TS_NOP}
};
static const struct telnet_special ssh2_transport_specials[] = {
{"IGNORE message", TS_NOP},
{"Repeat key exchange", TS_REKEY},
};
static const struct telnet_special ssh2_session_specials[] = {
{NULL, TS_SEP},
{"Break", TS_BRK},
/* These are the signal names defined by draft-ietf-secsh-connect-23.
* They include all the ISO C signals, but are a subset of the POSIX
* required signals. */
{"SIGINT (Interrupt)", TS_SIGINT},
{"SIGTERM (Terminate)", TS_SIGTERM},
{"SIGKILL (Kill)", TS_SIGKILL},
{"SIGQUIT (Quit)", TS_SIGQUIT},
{"SIGHUP (Hangup)", TS_SIGHUP},
{"More signals", TS_SUBMENU},
{"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM},
{"SIGFPE", TS_SIGFPE}, {"SIGILL", TS_SIGILL},
{"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV},
{"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2},
{NULL, TS_EXITMENU}
};
static const struct telnet_special specials_end[] = {
{NULL, TS_EXITMENU}
};
/* XXX review this length for any changes: */
static struct telnet_special ssh_specials[lenof(ssh2_transport_specials) +
lenof(ssh2_session_specials) +
lenof(specials_end)];
Ssh ssh = (Ssh) handle;
int i = 0;
#define ADD_SPECIALS(name) \
do { \
assert((i + lenof(name)) <= lenof(ssh_specials)); \
memcpy(&ssh_specials[i], name, sizeof name); \
i += lenof(name); \
} while(0)
if (ssh->version == 1) {
/* Don't bother offering IGNORE if we've decided the remote
* won't cope with it, since we wouldn't bother sending it if
* asked anyway. */
if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
ADD_SPECIALS(ssh1_ignore_special);
} else if (ssh->version == 2) {
ADD_SPECIALS(ssh2_transport_specials);
if (ssh->mainchan)
ADD_SPECIALS(ssh2_session_specials);
} /* else we're not ready yet */
if (i) {
ADD_SPECIALS(specials_end);
return ssh_specials;
} else {
return NULL;
}
#undef ADD_SPECIALS
}
/*
* Send Telnet special codes. TS_EOF is useful for `plink', so you
* can send an EOF and collect resulting output (e.g. `plink
* hostname sort').
*/
static void ssh_special(void *handle, Telnet_Special code)
{
Ssh ssh = (Ssh) handle;
struct Packet *pktout;
if (code == TS_EOF) {
if (ssh->state != SSH_STATE_SESSION) {
/*
* Buffer the EOF in case we are pre-SESSION, so we can
* send it as soon as we reach SESSION.
*/
if (code == TS_EOF)
ssh->eof_needed = TRUE;
return;
}
if (ssh->version == 1) {
send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
} else if (ssh->mainchan) {
struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid);
ssh2_pkt_send(ssh, pktout);
}
logevent("Sent EOF message");
} else if (code == TS_PING || code == TS_NOP) {
if (ssh->state == SSH_STATE_CLOSED
|| ssh->state == SSH_STATE_PREPACKET) return;
if (ssh->version == 1) {
if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
} else {
pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
ssh2_pkt_addstring_start(pktout);
ssh2_pkt_send_noqueue(ssh, pktout);
}
} else if (code == TS_REKEY) {
if (!ssh->kex_in_progress && ssh->version == 2) {
do_ssh2_transport(ssh, "at user request", -1, NULL);
}
} else if (code == TS_BRK) {
if (ssh->state == SSH_STATE_CLOSED
|| ssh->state == SSH_STATE_PREPACKET) return;
if (ssh->version == 1) {
logevent("Unable to send BREAK signal in SSH1");
} else if (ssh->mainchan) {
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid);
ssh2_pkt_addstring(pktout, "break");
ssh2_pkt_addbool(pktout, 0);
ssh2_pkt_adduint32(pktout, 0); /* default break length */
ssh2_pkt_send(ssh, pktout);
}
} else {
/* Is is a POSIX signal? */
char *signame = NULL;
if (code == TS_SIGABRT) signame = "ABRT";
if (code == TS_SIGALRM) signame = "ALRM";
if (code == TS_SIGFPE) signame = "FPE";
if (code == TS_SIGHUP) signame = "HUP";
if (code == TS_SIGILL) signame = "ILL";
if (code == TS_SIGINT) signame = "INT";
if (code == TS_SIGKILL) signame = "KILL";
if (code == TS_SIGPIPE) signame = "PIPE";
if (code == TS_SIGQUIT) signame = "QUIT";
if (code == TS_SIGSEGV) signame = "SEGV";
if (code == TS_SIGTERM) signame = "TERM";
if (code == TS_SIGUSR1) signame = "USR1";
if (code == TS_SIGUSR2) signame = "USR2";
/* The SSH-2 protocol does in principle support arbitrary named
* signals, including signame@domain, but we don't support those. */
if (signame) {
/* It's a signal. */
if (ssh->version == 2 && ssh->mainchan) {
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid);
ssh2_pkt_addstring(pktout, "signal");
ssh2_pkt_addbool(pktout, 0);
ssh2_pkt_addstring(pktout, signame);
ssh2_pkt_send(ssh, pktout);
logeventf(ssh, "Sent signal SIG%s", signame);
}
} else {
/* Never heard of it. Do nothing */
}
}
}
void *new_sock_channel(void *handle, Socket s)
{
Ssh ssh = (Ssh) handle;
struct ssh_channel *c;
c = snew(struct ssh_channel);
c->ssh = ssh;
if (c) {
c->halfopen = TRUE;
c->localid = alloc_channel_id(ssh);
c->closes = 0;
c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
c->u.pfd.s = s;
bufchain_init(&c->v.v2.outbuffer);
add234(ssh->channels, c);
}
return c;
}
/*
* This is called when stdout/stderr (the entity to which
* from_backend sends data) manages to clear some backlog.
*/
static void ssh_unthrottle(void *handle, int bufsize)
{
Ssh ssh = (Ssh) handle;
if (ssh->version == 1) {
if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
ssh->v1_stdout_throttling = 0;
ssh1_throttle(ssh, -1);
}
} else {
if (ssh->mainchan && ssh->mainchan->closes == 0)
ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
}
}
void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
{
struct ssh_channel *c = (struct ssh_channel *)channel;
Ssh ssh = c->ssh;
struct Packet *pktout;
logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
if (ssh->version == 1) {
send_packet(ssh, SSH1_MSG_PORT_OPEN,
PKT_INT, c->localid,
PKT_STR, hostname,
PKT_INT, port,
/* PKT_STR, <org:orgport>, */
PKT_END);
} else {
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
ssh2_pkt_addstring(pktout, "direct-tcpip");
ssh2_pkt_adduint32(pktout, c->localid);
c->v.v2.locwindow = OUR_V2_WINSIZE;
ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
ssh2_pkt_addstring(pktout, hostname);
ssh2_pkt_adduint32(pktout, port);
/*
* We make up values for the originator data; partly it's
* too much hassle to keep track, and partly I'm not
* convinced the server should be told details like that
* about my local network configuration.
*/
ssh2_pkt_addstring(pktout, "client-side-connection");
ssh2_pkt_adduint32(pktout, 0);
ssh2_pkt_send(ssh, pktout);
}
}
static Socket ssh_socket(void *handle)
{
Ssh ssh = (Ssh) handle;
return ssh->s;
}
static int ssh_sendok(void *handle)
{
Ssh ssh = (Ssh) handle;
return ssh->send_ok;
}
static int ssh_ldisc(void *handle, int option)
{
Ssh ssh = (Ssh) handle;
if (option == LD_ECHO)
return ssh->echoing;
if (option == LD_EDIT)
return ssh->editing;
return FALSE;
}
static void ssh_provide_ldisc(void *handle, void *ldisc)
{
Ssh ssh = (Ssh) handle;
ssh->ldisc = ldisc;
}
static void ssh_provide_logctx(void *handle, void *logctx)
{
Ssh ssh = (Ssh) handle;
ssh->logctx = logctx;
}
static int ssh_return_exitcode(void *handle)
{
Ssh ssh = (Ssh) handle;
if (ssh->s != NULL)
return -1;
else
return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
}
/*
* cfg_info for SSH is the currently running version of the
* protocol. (1 for 1; 2 for 2; 0 for not-decided-yet.)
*/
static int ssh_cfg_info(void *handle)
{
Ssh ssh = (Ssh) handle;
return ssh->version;
}
/*
* Gross hack: pscp will try to start SFTP but fall back to scp1 if
* that fails. This variable is the means by which scp.c can reach
* into the SSH code and find out which one it got.
*/
extern int ssh_fallback_cmd(void *handle)
{
Ssh ssh = (Ssh) handle;
return ssh->fallback_cmd;
}
Backend ssh_backend = {
ssh_init,
ssh_free,
ssh_reconfig,
ssh_send,
ssh_sendbuffer,
ssh_size,
ssh_special,
ssh_get_specials,
ssh_socket,
ssh_return_exitcode,
ssh_sendok,
ssh_ldisc,
ssh_provide_ldisc,
ssh_provide_logctx,
ssh_unthrottle,
ssh_cfg_info,
22
};
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