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putty/ssh.c

3143 строки
100 KiB
C
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#include <windows.h>
#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 logevent(s) { logevent(s); \
if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
fprintf(stderr, "%s\n", s); }
#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, sk_close(s), \
s = NULL, connection_fatal msg )
#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 SSH_AGENTC_REQUEST_RSA_IDENTITIES 1 /* 0x1 */
#define SSH_AGENT_RSA_IDENTITIES_ANSWER 2 /* 0x2 */
#define SSH_AGENTC_RSA_CHALLENGE 3 /* 0x3 */
#define SSH_AGENT_RSA_RESPONSE 4 /* 0x4 */
#define SSH_AGENT_FAILURE 5 /* 0x5 */
#define SSH_AGENT_SUCCESS 6 /* 0x6 */
#define SSH_AGENTC_ADD_RSA_IDENTITY 7 /* 0x7 */
#define SSH_AGENTC_REMOVE_RSA_IDENTITY 8 /* 0x8 */
#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_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_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 */
#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_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 */
#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); }
enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
/* Coroutine mechanics for the sillier bits of the code */
#define crBegin1 static int crLine = 0;
#define crBegin2 switch(crLine) { case 0:;
#define crBegin crBegin1; crBegin2;
#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))
extern const struct ssh_cipher ssh_3des;
extern const struct ssh_cipher ssh_3des_ssh2;
extern const struct ssh_cipher ssh_des;
extern const struct ssh_cipher ssh_blowfish_ssh1;
extern const struct ssh_cipher ssh_blowfish_ssh2;
extern char *x11_init (Socket *, char *, void *);
extern void x11_close (Socket);
extern void x11_send (Socket , char *, int);
extern void x11_invent_auth(char *, int, char *, int);
/*
* Ciphers for SSH2. We miss out single-DES because it isn't
* supported; also 3DES and Blowfish are both done differently from
* SSH1. (3DES uses outer chaining; Blowfish has the opposite
* endianness and different-sized keys.)
*/
const static struct ssh_cipher *ciphers[] = { &ssh_blowfish_ssh2, &ssh_3des_ssh2 };
extern const struct ssh_kex ssh_diffiehellman;
const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman };
extern const struct ssh_signkey ssh_dss;
const static struct ssh_signkey *hostkey_algs[] = { &ssh_dss };
extern const struct ssh_mac ssh_md5, ssh_sha1, ssh_sha1_buggy;
static void nullmac_key(unsigned char *key) { }
static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { }
static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; }
const static struct ssh_mac ssh_mac_none = {
nullmac_key, 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) { }
static int ssh_comp_none_block(unsigned char *block, int len,
unsigned char **outblock, int *outlen) {
return 0;
}
const static struct ssh_compress ssh_comp_none = {
"none",
ssh_comp_none_init, ssh_comp_none_block,
ssh_comp_none_init, ssh_comp_none_block
};
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,
};
/*
* 2-3-4 tree storing channels.
*/
struct ssh_channel {
unsigned remoteid, localid;
int type;
int closes;
struct ssh2_data_channel {
unsigned char *outbuffer;
unsigned outbuflen, outbufsize;
unsigned remwindow, remmaxpkt;
} v2;
union {
struct ssh_agent_channel {
unsigned char *message;
unsigned char msglen[4];
int lensofar, totallen;
} a;
struct ssh_x11_channel {
Socket s;
} x11;
} u;
};
struct Packet {
long length;
int type;
unsigned char *data;
unsigned char *body;
long savedpos;
long maxlen;
};
static SHA_State exhash, exhashbase;
static Socket s = NULL;
static unsigned char session_key[32];
static int ssh1_compressing;
static int ssh_agentfwd_enabled;
static int ssh_X11_fwd_enabled;
static const struct ssh_cipher *cipher = NULL;
static const struct ssh_cipher *cscipher = NULL;
static const struct ssh_cipher *sccipher = NULL;
static const struct ssh_mac *csmac = NULL;
static const struct ssh_mac *scmac = NULL;
static const struct ssh_compress *cscomp = NULL;
static const struct ssh_compress *sccomp = NULL;
static const struct ssh_kex *kex = NULL;
static const struct ssh_signkey *hostkey = NULL;
int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL;
static char *savedhost;
static int savedport;
static int ssh_send_ok;
static int ssh_echoing, ssh_editing;
static tree234 *ssh_channels; /* indexed by local id */
static struct ssh_channel *mainchan; /* primary session channel */
static enum {
SSH_STATE_PREPACKET,
SSH_STATE_BEFORE_SIZE,
SSH_STATE_INTERMED,
SSH_STATE_SESSION,
SSH_STATE_CLOSED
} ssh_state = SSH_STATE_PREPACKET;
static int size_needed = FALSE, eof_needed = FALSE;
static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
static int ssh_version;
static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
static void ssh_size(void);
static void ssh_special (Telnet_Special);
static void ssh2_try_send(struct ssh_channel *c);
static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
static int (*s_rdpkt)(unsigned char **data, int *datalen);
static struct rdpkt1_state_tag {
long len, pad, biglen, to_read;
unsigned long realcrc, gotcrc;
unsigned char *p;
int i;
int chunk;
} rdpkt1_state;
static struct rdpkt2_state_tag {
long len, pad, payload, packetlen, maclen;
int i;
int cipherblk;
unsigned long incoming_sequence;
} rdpkt2_state;
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 void c_write (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(1, buf, len);
}
/*
* 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 the additional nr of bytes needed, or 0 when
* a complete packet is available.
*/
static int ssh1_rdpkt(unsigned char **data, int *datalen)
{
struct rdpkt1_state_tag *st = &rdpkt1_state;
crBegin;
next_packet:
pktin.type = 0;
pktin.length = 0;
for (st->i = st->len = 0; st->i < 4; st->i++) {
while ((*datalen) == 0)
crReturn(4-st->i);
st->len = (st->len << 8) + **data;
(*data)++, (*datalen)--;
}
#ifdef FWHACK
if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
st->len = 0x300; /* big enough to carry to end */
}
#endif
st->pad = 8 - (st->len % 8);
st->biglen = st->len + st->pad;
pktin.length = st->len - 5;
if (pktin.maxlen < st->biglen) {
pktin.maxlen = st->biglen;
pktin.data = (pktin.data == NULL ? smalloc(st->biglen+APIEXTRA) :
srealloc(pktin.data, st->biglen+APIEXTRA));
if (!pktin.data)
fatalbox("Out of memory");
}
st->to_read = st->biglen;
st->p = pktin.data;
while (st->to_read > 0) {
st->chunk = st->to_read;
while ((*datalen) == 0)
crReturn(st->to_read);
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 (cipher)
cipher->decrypt(pktin.data, st->biglen);
#if 0
debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
for (st->i = 0; st->i < st->biglen; st->i++)
debug((" %02x", (unsigned char)pktin.data[st->i]));
debug(("\r\n"));
#endif
st->realcrc = crc32(pktin.data, st->biglen-4);
st->gotcrc = GET_32BIT(pktin.data+st->biglen-4);
if (st->gotcrc != st->realcrc) {
bombout(("Incorrect CRC received on packet"));
crReturn(0);
}
pktin.body = pktin.data + st->pad + 1;
if (ssh1_compressing) {
unsigned char *decompblk;
int decomplen;
#if 0
int i;
debug(("Packet payload pre-decompression:\n"));
for (i = -1; i < pktin.length; i++)
debug((" %02x", (unsigned char)pktin.body[i]));
debug(("\r\n"));
#endif
zlib_decompress_block(pktin.body-1, pktin.length+1,
&decompblk, &decomplen);
if (pktin.maxlen < st->pad + decomplen) {
pktin.maxlen = st->pad + decomplen;
pktin.data = srealloc(pktin.data, pktin.maxlen+APIEXTRA);
pktin.body = pktin.data + st->pad + 1;
if (!pktin.data)
fatalbox("Out of memory");
}
memcpy(pktin.body-1, decompblk, decomplen);
sfree(decompblk);
pktin.length = decomplen-1;
#if 0
debug(("Packet payload post-decompression:\n"));
for (i = -1; i < pktin.length; i++)
debug((" %02x", (unsigned char)pktin.body[i]));
debug(("\r\n"));
#endif
}
if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
pktin.type == SSH1_SMSG_STDERR_DATA ||
pktin.type == SSH1_MSG_DEBUG ||
pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
long strlen = GET_32BIT(pktin.body);
if (strlen + 4 != pktin.length) {
bombout(("Received data packet with bogus string length"));
crReturn(0);
}
}
pktin.type = pktin.body[-1];
if (pktin.type == SSH1_MSG_DEBUG) {
/* log debug message */
char buf[80];
int strlen = GET_32BIT(pktin.body);
strcpy(buf, "Remote: ");
if (strlen > 70) strlen = 70;
memcpy(buf+8, pktin.body+4, strlen);
buf[8+strlen] = '\0';
logevent(buf);
goto next_packet;
} else if (pktin.type == SSH1_MSG_IGNORE) {
/* do nothing */
goto next_packet;
}
crFinish(0);
}
static int ssh2_rdpkt(unsigned char **data, int *datalen)
{
struct rdpkt2_state_tag *st = &rdpkt2_state;
crBegin;
next_packet:
pktin.type = 0;
pktin.length = 0;
if (sccipher)
st->cipherblk = sccipher->blksize;
else
st->cipherblk = 8;
if (st->cipherblk < 8)
st->cipherblk = 8;
if (pktin.maxlen < st->cipherblk) {
pktin.maxlen = st->cipherblk;
pktin.data = (pktin.data == NULL ? smalloc(st->cipherblk+APIEXTRA) :
srealloc(pktin.data, st->cipherblk+APIEXTRA));
if (!pktin.data)
fatalbox("Out of memory");
}
/*
* 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(st->cipherblk-st->i);
pktin.data[st->i] = *(*data)++;
(*datalen)--;
}
#ifdef FWHACK
if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
/* FIXME */
}
#endif
if (sccipher)
sccipher->decrypt(pktin.data, st->cipherblk);
/*
* Now get the length and padding figures.
*/
st->len = GET_32BIT(pktin.data);
st->pad = pktin.data[4];
/*
* This enables us to deduce the payload length.
*/
st->payload = st->len - st->pad - 1;
pktin.length = st->payload + 5;
/*
* So now we can work out the total packet length.
*/
st->packetlen = st->len + 4;
st->maclen = scmac ? scmac->len : 0;
/*
* Adjust memory allocation if packet is too big.
*/
if (pktin.maxlen < st->packetlen+st->maclen) {
pktin.maxlen = st->packetlen+st->maclen;
pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
srealloc(pktin.data, pktin.maxlen+APIEXTRA));
if (!pktin.data)
fatalbox("Out of memory");
}
/*
* 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(st->packetlen + st->maclen - st->i);
pktin.data[st->i] = *(*data)++;
(*datalen)--;
}
/* Decrypt everything _except_ the MAC. */
if (sccipher)
sccipher->decrypt(pktin.data + st->cipherblk,
st->packetlen - st->cipherblk);
#if 0
debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
for (st->i = 0; st->i < st->packetlen; st->i++)
debug((" %02x", (unsigned char)pktin.data[st->i]));
debug(("\r\n"));
#endif
/*
* Check the MAC.
*/
if (scmac && !scmac->verify(pktin.data, st->len+4, st->incoming_sequence)) {
bombout(("Incorrect MAC received on packet"));
crReturn(0);
}
st->incoming_sequence++; /* whether or not we MACed */
/*
* Decompress packet payload.
*/
{
unsigned char *newpayload;
int newlen;
if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5,
&newpayload, &newlen)) {
if (pktin.maxlen < newlen+5) {
pktin.maxlen = newlen+5;
pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
srealloc(pktin.data, pktin.maxlen+APIEXTRA));
if (!pktin.data)
fatalbox("Out of memory");
}
pktin.length = 5 + newlen;
memcpy(pktin.data+5, newpayload, newlen);
#if 0
debug(("Post-decompression payload:\r\n"));
for (st->i = 0; st->i < newlen; st->i++)
debug((" %02x", (unsigned char)pktin.data[5+st->i]));
debug(("\r\n"));
#endif
sfree(newpayload);
}
}
pktin.savedpos = 6;
pktin.type = pktin.data[5];
if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
goto next_packet; /* FIXME: print DEBUG message */
crFinish(0);
}
static void ssh1_pktout_size(int len) {
int pad, biglen;
len += 5; /* type and CRC */
pad = 8 - (len%8);
biglen = len + pad;
pktout.length = len-5;
if (pktout.maxlen < biglen) {
pktout.maxlen = biglen;
#ifdef MSCRYPTOAPI
/* Allocate enough buffer space for extra block
* for MS CryptEncrypt() */
pktout.data = (pktout.data == NULL ? smalloc(biglen+12) :
srealloc(pktout.data, biglen+12));
#else
pktout.data = (pktout.data == NULL ? smalloc(biglen+4) :
srealloc(pktout.data, biglen+4));
#endif
if (!pktout.data)
fatalbox("Out of memory");
}
pktout.body = pktout.data+4+pad+1;
}
static void s_wrpkt_start(int type, int len) {
ssh1_pktout_size(len);
pktout.type = type;
}
static void s_wrpkt(void) {
int pad, len, biglen, i;
unsigned long crc;
pktout.body[-1] = pktout.type;
if (ssh1_compressing) {
unsigned char *compblk;
int complen;
#if 0
debug(("Packet payload pre-compression:\n"));
for (i = -1; i < pktout.length; i++)
debug((" %02x", (unsigned char)pktout.body[i]));
debug(("\r\n"));
#endif
zlib_compress_block(pktout.body-1, pktout.length+1,
&compblk, &complen);
ssh1_pktout_size(complen-1);
memcpy(pktout.body-1, compblk, complen);
sfree(compblk);
#if 0
debug(("Packet payload post-compression:\n"));
for (i = -1; i < pktout.length; i++)
debug((" %02x", (unsigned char)pktout.body[i]));
debug(("\r\n"));
#endif
}
len = pktout.length + 5; /* type and CRC */
pad = 8 - (len%8);
biglen = len + pad;
for (i=0; i<pad; i++)
pktout.data[i+4] = random_byte();
crc = crc32(pktout.data+4, biglen-4);
PUT_32BIT(pktout.data+biglen, crc);
PUT_32BIT(pktout.data, len);
#if 0
debug(("Sending packet len=%d\r\n", biglen+4));
for (i = 0; i < biglen+4; i++)
debug((" %02x", (unsigned char)pktout.data[i]));
debug(("\r\n"));
#endif
if (cipher)
cipher->encrypt(pktout.data+4, biglen);
sk_write(s, pktout.data, biglen+4);
}
/*
* Construct a packet with the specified contents and
* send it to the server.
*/
static void send_packet(int pkttype, ...)
{
va_list args;
unsigned char *p, *argp, argchar;
unsigned long argint;
int pktlen, argtype, arglen;
Bignum bn;
pktlen = 0;
va_start(args, pkttype);
while ((argtype = va_arg(args, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
(void) va_arg(args, int);
pktlen += 4;
break;
case PKT_CHAR:
(void) va_arg(args, char);
pktlen++;
break;
case PKT_DATA:
(void) va_arg(args, unsigned char *);
arglen = va_arg(args, int);
pktlen += arglen;
break;
case PKT_STR:
argp = va_arg(args, unsigned char *);
arglen = strlen(argp);
pktlen += 4 + arglen;
break;
case PKT_BIGNUM:
bn = va_arg(args, Bignum);
pktlen += ssh1_bignum_length(bn);
break;
default:
assert(0);
}
}
va_end(args);
s_wrpkt_start(pkttype, pktlen);
p = pktout.body;
va_start(args, pkttype);
while ((argtype = va_arg(args, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
argint = va_arg(args, int);
PUT_32BIT(p, argint);
p += 4;
break;
case PKT_CHAR:
argchar = va_arg(args, unsigned char);
*p = argchar;
p++;
break;
case PKT_DATA:
argp = va_arg(args, unsigned char *);
arglen = va_arg(args, int);
memcpy(p, argp, arglen);
p += arglen;
break;
case PKT_STR:
argp = va_arg(args, unsigned char *);
arglen = strlen(argp);
PUT_32BIT(p, arglen);
memcpy(p + 4, argp, arglen);
p += 4 + arglen;
break;
case PKT_BIGNUM:
bn = va_arg(args, Bignum);
p += ssh1_write_bignum(p, bn);
break;
}
}
va_end(args);
s_wrpkt();
}
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 routine for putting an SSH-protocol `string' 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);
}
/*
* SSH2 packet construction functions.
*/
static void ssh2_pkt_ensure(int length) {
if (pktout.maxlen < length) {
pktout.maxlen = length + 256;
pktout.data = (pktout.data == NULL ? smalloc(pktout.maxlen+APIEXTRA) :
srealloc(pktout.data, pktout.maxlen+APIEXTRA));
if (!pktout.data)
fatalbox("Out of memory");
}
}
static void ssh2_pkt_adddata(void *data, int len) {
pktout.length += len;
ssh2_pkt_ensure(pktout.length);
memcpy(pktout.data+pktout.length-len, data, len);
}
static void ssh2_pkt_addbyte(unsigned char byte) {
ssh2_pkt_adddata(&byte, 1);
}
static void ssh2_pkt_init(int pkt_type) {
pktout.length = 5;
ssh2_pkt_addbyte((unsigned char)pkt_type);
}
static void ssh2_pkt_addbool(unsigned char value) {
ssh2_pkt_adddata(&value, 1);
}
static void ssh2_pkt_adduint32(unsigned long value) {
unsigned char x[4];
PUT_32BIT(x, value);
ssh2_pkt_adddata(x, 4);
}
static void ssh2_pkt_addstring_start(void) {
ssh2_pkt_adduint32(0);
pktout.savedpos = pktout.length;
}
static void ssh2_pkt_addstring_str(char *data) {
ssh2_pkt_adddata(data, strlen(data));
PUT_32BIT(pktout.data + pktout.savedpos - 4,
pktout.length - pktout.savedpos);
}
static void ssh2_pkt_addstring_data(char *data, int len) {
ssh2_pkt_adddata(data, len);
PUT_32BIT(pktout.data + pktout.savedpos - 4,
pktout.length - pktout.savedpos);
}
static void ssh2_pkt_addstring(char *data) {
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_str(data);
}
static char *ssh2_mpint_fmt(Bignum b, int *len) {
unsigned char *p;
int i, n = b[0];
p = smalloc(n * 2 + 1);
if (!p)
fatalbox("out of memory");
p[0] = 0;
for (i = 0; i < n; i++) {
p[i*2+1] = (b[n-i] >> 8) & 0xFF;
p[i*2+2] = (b[n-i] ) & 0xFF;
}
i = 0;
while (p[i] == 0 && (p[i+1] & 0x80) == 0)
i++;
memmove(p, p+i, n*2+1-i);
*len = n*2+1-i;
return p;
}
static void ssh2_pkt_addmp(Bignum b) {
unsigned char *p;
int len;
p = ssh2_mpint_fmt(b, &len);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(p, len);
sfree(p);
}
static void ssh2_pkt_send(void) {
int cipherblk, maclen, padding, i;
static unsigned long outgoing_sequence = 0;
/*
* Compress packet payload.
*/
#if 0
debug(("Pre-compression payload:\r\n"));
for (i = 5; i < pktout.length; i++)
debug((" %02x", (unsigned char)pktout.data[i]));
debug(("\r\n"));
#endif
{
unsigned char *newpayload;
int newlen;
if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5,
&newpayload, &newlen)) {
pktout.length = 5;
ssh2_pkt_adddata(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.
*/
cipherblk = cipher ? cipher->blksize : 8; /* block size */
cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
padding = 4;
padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
maclen = csmac ? csmac->len : 0;
ssh2_pkt_ensure(pktout.length + padding + maclen);
pktout.data[4] = padding;
for (i = 0; i < padding; i++)
pktout.data[pktout.length + i] = random_byte();
PUT_32BIT(pktout.data, pktout.length + padding - 4);
if (csmac)
csmac->generate(pktout.data, pktout.length + padding,
outgoing_sequence);
outgoing_sequence++; /* whether or not we MACed */
#if 0
debug(("Sending packet len=%d\r\n", pktout.length+padding));
for (i = 0; i < pktout.length+padding; i++)
debug((" %02x", (unsigned char)pktout.data[i]));
debug(("\r\n"));
#endif
if (cscipher)
cscipher->encrypt(pktout.data, pktout.length + padding);
sk_write(s, pktout.data, pktout.length + padding + maclen);
}
#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(("\r\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);
}
/*
* SSH2 packet decode functions.
*/
static unsigned long ssh2_pkt_getuint32(void) {
unsigned long value;
if (pktin.length - pktin.savedpos < 4)
return 0; /* arrgh, no way to decline (FIXME?) */
value = GET_32BIT(pktin.data+pktin.savedpos);
pktin.savedpos += 4;
return value;
}
static void ssh2_pkt_getstring(char **p, int *length) {
*p = NULL;
if (pktin.length - pktin.savedpos < 4)
return;
*length = GET_32BIT(pktin.data+pktin.savedpos);
pktin.savedpos += 4;
if (pktin.length - pktin.savedpos < *length)
return;
*p = pktin.data+pktin.savedpos;
pktin.savedpos += *length;
}
static Bignum ssh2_pkt_getmp(void) {
char *p;
int i, j, length;
Bignum b;
ssh2_pkt_getstring(&p, &length);
if (!p)
return NULL;
if (p[0] & 0x80) {
bombout(("internal error: Can't handle negative mpints"));
return NULL;
}
b = newbn((length+1)/2);
for (i = 0; i < length; i++) {
j = length - 1 - i;
if (j & 1)
b[j/2+1] |= ((unsigned char)p[i]) << 8;
else
b[j/2+1] |= ((unsigned char)p[i]);
}
while (b[0] > 1 && b[b[0]] == 0) b[0]--;
return b;
}
static int do_ssh_init(unsigned char c) {
static char *vsp;
static char version[10];
static char vstring[80];
static char vlog[sizeof(vstring)+20];
static int i;
crBegin;
/* Search for the string "SSH-" in the input. */
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') i = transS[i];
else if (c == 'H') i = transH[i];
else if (c == '-') i = transminus[i];
else i = 0;
if (i < 0)
break;
crReturn(1); /* get another character */
}
strcpy(vstring, "SSH-");
vsp = vstring+4;
i = 0;
while (1) {
crReturn(1); /* get another char */
if (vsp < vstring+sizeof(vstring)-1)
*vsp++ = c;
if (i >= 0) {
if (c == '-') {
version[i] = '\0';
i = -1;
} else if (i < sizeof(version)-1)
version[i++] = c;
}
else if (c == '\n')
break;
}
ssh_agentfwd_enabled = FALSE;
rdpkt2_state.incoming_sequence = 0;
*vsp = 0;
sprintf(vlog, "Server version: %s", vstring);
vlog[strcspn(vlog, "\r\n")] = '\0';
logevent(vlog);
/*
* Server version "1.99" means we can choose whether we use v1
* or v2 protocol. Choice is based on cfg.sshprot.
*/
if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
/*
* This is a v2 server. Begin v2 protocol.
*/
char *verstring = "SSH-2.0-PuTTY";
SHA_Init(&exhashbase);
/*
* Hash our version string and their version string.
*/
sha_string(&exhashbase, verstring, strlen(verstring));
sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
sprintf(vstring, "%s\n", verstring);
sprintf(vlog, "We claim version: %s", verstring);
logevent(vlog);
logevent("Using SSH protocol version 2");
sk_write(s, vstring, strlen(vstring));
ssh_protocol = ssh2_protocol;
ssh_version = 2;
s_rdpkt = ssh2_rdpkt;
} else {
/*
* This is a v1 server. Begin v1 protocol.
*/
sprintf(vstring, "SSH-%s-PuTTY\n",
(ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
sprintf(vlog, "We claim version: %s", vstring);
vlog[strcspn(vlog, "\r\n")] = '\0';
logevent(vlog);
logevent("Using SSH protocol version 1");
sk_write(s, vstring, strlen(vstring));
ssh_protocol = ssh1_protocol;
ssh_version = 1;
s_rdpkt = ssh1_rdpkt;
}
ssh_state = SSH_STATE_BEFORE_SIZE;
crFinish(0);
}
static void ssh_gotdata(unsigned char *data, int datalen)
{
crBegin;
/*
* 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;
if (datalen == 0)
crReturnV; /* more data please */
ret = do_ssh_init(*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) {
if ( s_rdpkt(&data, &datalen) == 0 ) {
ssh_protocol(NULL, 0, 1);
if (ssh_state == SSH_STATE_CLOSED) {
return;
}
}
}
crReturnV;
}
crFinishV;
}
static int ssh_receive(Socket skt, int urgent, char *data, int len) {
if (urgent==3) {
/* A socket error has occurred. */
ssh_state = SSH_STATE_CLOSED;
s = NULL;
connection_fatal(data);
len = 0;
}
if (!len) {
/* Connection has closed. */
ssh_state = SSH_STATE_CLOSED;
sk_close(s);
s = NULL;
return 0;
}
ssh_gotdata (data, len);
if (ssh_state == SSH_STATE_CLOSED) {
if (s) {
sk_close(s);
s = NULL;
}
return 0;
}
return 1;
}
/*
* Connect to specified host and port.
* Returns an error message, or NULL on success.
* Also places the canonical host name into `realhost'.
*/
static char *connect_to_host(char *host, int port, char **realhost)
{
SockAddr addr;
char *err;
#ifdef FWHACK
char *FWhost;
int FWport;
#endif
savedhost = smalloc(1+strlen(host));
if (!savedhost)
fatalbox("Out of memory");
strcpy(savedhost, host);
if (port < 0)
port = 22; /* default ssh port */
savedport = port;
#ifdef FWHACK
FWhost = host;
FWport = port;
host = FWSTR;
port = 23;
#endif
/*
* Try to find host.
*/
addr = sk_namelookup(host, realhost);
if ( (err = sk_addr_error(addr)) )
return err;
#ifdef FWHACK
*realhost = FWhost;
#endif
/*
* Open socket.
*/
s = sk_new(addr, port, 0, ssh_receive);
if ( (err = sk_socket_error(s)) )
return err;
#ifdef FWHACK
sk_write(s, "connect ", 8);
sk_write(s, FWhost, strlen(FWhost));
{
char buf[20];
sprintf(buf, " %d\n", FWport);
sk_write(s, buf, strlen(buf));
}
#endif
return NULL;
}
/*
* Handle the key exchange and user authentication phases.
*/
static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
{
int i, j, len;
unsigned char *rsabuf, *keystr1, *keystr2;
unsigned char cookie[8];
struct RSAKey servkey, hostkey;
struct MD5Context md5c;
static unsigned long supported_ciphers_mask, supported_auths_mask;
static int tried_publickey;
static unsigned char session_id[16];
int cipher_type;
static char username[100];
crBegin;
if (!ispkt) crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
bombout(("Public key packet not received"));
crReturn(0);
}
logevent("Received public keys");
memcpy(cookie, pktin.body, 8);
i = makekey(pktin.body+8, &servkey, &keystr1, 0);
j = makekey(pktin.body+8+i, &hostkey, &keystr2, 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);
}
supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
MD5Init(&md5c);
MD5Update(&md5c, keystr2, hostkey.bytes);
MD5Update(&md5c, keystr1, servkey.bytes);
MD5Update(&md5c, pktin.body, 8);
MD5Final(session_id, &md5c);
for (i=0; i<32; i++)
session_key[i] = random_byte();
len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
rsabuf = smalloc(len);
if (!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 = smalloc(len);
if (!keystr)
fatalbox("Out of memory");
rsastr_fmt(keystr, &hostkey);
rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
verify_ssh_host_key(savedhost, savedport, "rsa", keystr, fingerprint);
sfree(keystr);
}
for (i=0; i<32; i++) {
rsabuf[i] = session_key[i];
if (i < 16)
rsabuf[i] ^= session_id[i];
}
if (hostkey.bytes > servkey.bytes) {
rsaencrypt(rsabuf, 32, &servkey);
rsaencrypt(rsabuf, servkey.bytes, &hostkey);
} else {
rsaencrypt(rsabuf, 32, &hostkey);
rsaencrypt(rsabuf, hostkey.bytes, &servkey);
}
logevent("Encrypted session key");
cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
SSH_CIPHER_3DES;
if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
cipher_type = SSH_CIPHER_3DES;
}
switch (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(SSH1_CMSG_SESSION_KEY,
PKT_CHAR, cipher_type,
PKT_DATA, cookie, 8,
PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
PKT_DATA, rsabuf, len,
PKT_INT, 0,
PKT_END);
logevent("Trying to enable encryption...");
sfree(rsabuf);
cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
cipher_type == SSH_CIPHER_DES ? &ssh_des :
&ssh_3des;
cipher->sesskey(session_key);
crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_SUCCESS) {
bombout(("Encryption not successfully enabled"));
crReturn(0);
}
logevent("Successfully started encryption");
fflush(stdout);
{
static int pos = 0;
static char c;
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
c_write("login as: ", 10);
ssh_send_ok = 1;
while (pos >= 0) {
crWaitUntil(!ispkt);
while (inlen--) switch (c = *in++) {
case 10: case 13:
username[pos] = 0;
pos = -1;
break;
case 8: case 127:
if (pos > 0) {
c_write("\b \b", 3);
pos--;
}
break;
case 21: case 27:
while (pos > 0) {
c_write("\b \b", 3);
pos--;
}
break;
case 3: case 4:
random_save_seed();
exit(0);
break;
default:
if (((c >= ' ' && c <= '~') ||
((unsigned char)c >= 160)) && pos < 40) {
username[pos++] = c;
c_write(&c, 1);
}
break;
}
}
c_write("\r\n", 2);
username[strcspn(username, "\n\r")] = '\0';
} else {
strncpy(username, cfg.username, 99);
username[99] = '\0';
}
send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
{
char userlog[22+sizeof(username)];
sprintf(userlog, "Sent username \"%s\"", username);
logevent(userlog);
if (flags & FLAG_INTERACTIVE &&
(!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
strcat(userlog, "\r\n");
c_write(userlog, strlen(userlog));
}
}
}
crWaitUntil(ispkt);
tried_publickey = 0;
while (pktin.type == SSH1_SMSG_FAILURE) {
static char password[100];
static char prompt[200];
static int pos;
static char c;
static int pwpkt_type;
/*
* Show password prompt, having first obtained it via a TIS
* or CryptoCard exchange if we're doing TIS or CryptoCard
* authentication.
*/
pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
if (agent_exists()) {
/*
* Attempt RSA authentication using Pageant.
*/
static unsigned char request[5], *response, *p;
static int responselen;
static int i, nkeys;
static int authed = FALSE;
void *r;
logevent("Pageant is running. Requesting keys.");
/* Request the keys held by the agent. */
PUT_32BIT(request, 1);
request[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
agent_query(request, 5, &r, &responselen);
response = (unsigned char *)r;
if (response) {
p = response + 5;
nkeys = GET_32BIT(p); p += 4;
{ char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys);
logevent(buf); }
for (i = 0; i < nkeys; i++) {
static struct RSAKey key;
static Bignum challenge;
static char *commentp;
static int commentlen;
{ char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
logevent(buf); }
p += 4;
p += ssh1_read_bignum(p, &key.exponent);
p += ssh1_read_bignum(p, &key.modulus);
commentlen = GET_32BIT(p); p += 4;
commentp = p; p += commentlen;
send_packet(SSH1_CMSG_AUTH_RSA,
PKT_BIGNUM, key.modulus, PKT_END);
crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
logevent("Key refused");
continue;
}
logevent("Received RSA challenge");
ssh1_read_bignum(pktin.body, &challenge);
{
char *agentreq, *q, *ret;
int len, retlen;
len = 1 + 4; /* message type, bit count */
len += ssh1_bignum_length(key.exponent);
len += ssh1_bignum_length(key.modulus);
len += ssh1_bignum_length(challenge);
len += 16; /* session id */
len += 4; /* response format */
agentreq = smalloc(4 + len);
PUT_32BIT(agentreq, len);
q = agentreq + 4;
*q++ = SSH_AGENTC_RSA_CHALLENGE;
PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus));
q += 4;
q += ssh1_write_bignum(q, key.exponent);
q += ssh1_write_bignum(q, key.modulus);
q += ssh1_write_bignum(q, challenge);
memcpy(q, session_id, 16); q += 16;
PUT_32BIT(q, 1); /* response format */
agent_query(agentreq, len+4, &ret, &retlen);
sfree(agentreq);
if (ret) {
if (ret[4] == SSH_AGENT_RSA_RESPONSE) {
logevent("Sending Pageant's response");
send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
PKT_DATA, ret+5, 16, PKT_END);
sfree(ret);
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_SUCCESS) {
logevent("Pageant's response accepted");
if (flags & FLAG_VERBOSE) {
c_write("Authenticated using RSA key \"",
29);
c_write(commentp, commentlen);
c_write("\" from agent\r\n", 14);
}
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(key.exponent);
freebn(key.modulus);
freebn(challenge);
if (authed)
break;
}
}
if (authed)
break;
}
if (*cfg.keyfile && !tried_publickey)
pwpkt_type = SSH1_CMSG_AUTH_RSA;
if (pktin.type == SSH1_SMSG_FAILURE &&
cfg.try_tis_auth &&
(supported_auths_mask & (1<<SSH1_AUTH_TIS))) {
pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
logevent("Requested TIS authentication");
send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
logevent("TIS authentication declined");
if (flags & FLAG_INTERACTIVE)
c_write("TIS authentication refused.\r\n", 29);
} else {
int challengelen = ((pktin.body[0] << 24) |
(pktin.body[1] << 16) |
(pktin.body[2] << 8) |
(pktin.body[3]));
logevent("Received TIS challenge");
if (challengelen > sizeof(prompt)-1)
challengelen = sizeof(prompt)-1; /* prevent overrun */
memcpy(prompt, pktin.body+4, challengelen);
prompt[challengelen] = '\0';
}
}
if (pktin.type == SSH1_SMSG_FAILURE &&
cfg.try_tis_auth &&
(supported_auths_mask & (1<<SSH1_AUTH_CCARD))) {
pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
logevent("Requested CryptoCard authentication");
send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
logevent("CryptoCard authentication declined");
c_write("CryptoCard authentication refused.\r\n", 29);
} else {
int challengelen = ((pktin.body[0] << 24) |
(pktin.body[1] << 16) |
(pktin.body[2] << 8) |
(pktin.body[3]));
logevent("Received CryptoCard challenge");
if (challengelen > sizeof(prompt)-1)
challengelen = sizeof(prompt)-1; /* prevent overrun */
memcpy(prompt, pktin.body+4, challengelen);
strncpy(prompt + challengelen, "\r\nResponse : ",
sizeof(prompt)-challengelen);
prompt[sizeof(prompt)-1] = '\0';
}
}
if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
sprintf(prompt, "%.90s@%.90s's password: ",
username, savedhost);
}
if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
char *comment = NULL;
if (flags & FLAG_VERBOSE)
c_write("Trying public key authentication.\r\n", 35);
if (!rsakey_encrypted(cfg.keyfile, &comment)) {
if (flags & FLAG_VERBOSE)
c_write("No passphrase required.\r\n", 25);
goto tryauth;
}
sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
sfree(comment);
}
if (ssh_get_password) {
if (!ssh_get_password(prompt, password, sizeof(password))) {
/*
* get_password failed to get a password (for
* example because one was supplied on the command
* line which has already failed to work).
* Terminate.
*/
logevent("No more passwords to try");
ssh_state = SSH_STATE_CLOSED;
crReturn(1);
}
} else {
c_write(prompt, strlen(prompt));
pos = 0;
ssh_send_ok = 1;
while (pos >= 0) {
crWaitUntil(!ispkt);
while (inlen--) switch (c = *in++) {
case 10: case 13:
password[pos] = 0;
pos = -1;
break;
case 8: case 127:
if (pos > 0)
pos--;
break;
case 21: case 27:
pos = 0;
break;
case 3: case 4:
random_save_seed();
exit(0);
break;
default:
if (((c >= ' ' && c <= '~') ||
((unsigned char)c >= 160)) && pos < sizeof(password))
password[pos++] = c;
break;
}
}
c_write("\r\n", 2);
}
tryauth:
if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
/*
* Try public key authentication with the specified
* key file.
*/
static struct RSAKey pubkey;
static Bignum challenge, response;
static int i;
static unsigned char buffer[32];
tried_publickey = 1;
i = loadrsakey(cfg.keyfile, &pubkey, NULL, password);
if (i == 0) {
c_write("Couldn't load public key from ", 30);
c_write(cfg.keyfile, strlen(cfg.keyfile));
c_write(".\r\n", 3);
continue; /* go and try password */
}
if (i == -1) {
c_write("Wrong passphrase.\r\n", 19);
tried_publickey = 0;
continue; /* try again */
}
/*
* Send a public key attempt.
*/
send_packet(SSH1_CMSG_AUTH_RSA,
PKT_BIGNUM, pubkey.modulus, PKT_END);
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_FAILURE) {
c_write("Server refused our public key.\r\n", 32);
continue; /* go and try password */
}
if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
bombout(("Bizarre response to offer of public key"));
crReturn(0);
}
ssh1_read_bignum(pktin.body, &challenge);
response = rsadecrypt(challenge, &pubkey);
freebn(pubkey.private_exponent); /* burn the evidence */
for (i = 0; i < 32; i += 2) {
buffer[i] = response[16-i/2] >> 8;
buffer[i+1] = response[16-i/2] & 0xFF;
}
MD5Init(&md5c);
MD5Update(&md5c, buffer, 32);
MD5Update(&md5c, session_id, 16);
MD5Final(buffer, &md5c);
send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
PKT_DATA, buffer, 16, PKT_END);
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_FAILURE) {
if (flags & FLAG_VERBOSE)
c_write("Failed to authenticate with our public key.\r\n",
45);
continue; /* go and try password */
} else if (pktin.type != SSH1_SMSG_SUCCESS) {
bombout(("Bizarre response to RSA authentication response"));
crReturn(0);
}
break; /* we're through! */
} else {
send_packet(pwpkt_type, PKT_STR, password, PKT_END);
}
logevent("Sent password");
memset(password, 0, strlen(password));
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_FAILURE) {
if (flags & FLAG_VERBOSE)
c_write("Access denied\r\n", 15);
logevent("Authentication refused");
} else if (pktin.type == SSH1_MSG_DISCONNECT) {
logevent("Received disconnect request");
ssh_state = SSH_STATE_CLOSED;
crReturn(1);
} else if (pktin.type != SSH1_SMSG_SUCCESS) {
bombout(("Strange packet received, type %d", pktin.type));
crReturn(0);
}
}
logevent("Authentication successful");
crFinish(1);
}
void sshfwd_close(struct ssh_channel *c) {
if (c) {
if (ssh_version == 1) {
send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, PKT_END);
} else {
ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_send();
}
c->closes = 1;
if (c->type == CHAN_X11) {
c->u.x11.s = NULL;
logevent("X11 connection terminated");
}
}
}
void sshfwd_write(struct ssh_channel *c, char *buf, int len) {
if (ssh_version == 1) {
send_packet(SSH1_MSG_CHANNEL_DATA,
PKT_INT, c->remoteid,
PKT_INT, len,
PKT_DATA, buf, len,
PKT_END);
} else {
ssh2_add_channel_data(c, buf, len);
ssh2_try_send(c);
}
}
static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
crBegin;
random_init();
while (!do_ssh1_login(in, inlen, ispkt)) {
crReturnV;
}
if (ssh_state == SSH_STATE_CLOSED)
crReturnV;
if (cfg.agentfwd && agent_exists()) {
logevent("Requesting agent forwarding");
send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
do { crReturnV; } while (!ispkt);
if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
logevent("Agent forwarding refused");
} else {
logevent("Agent forwarding enabled");
ssh_agentfwd_enabled = TRUE;
}
}
if (cfg.x11_forward) {
char proto[20], data[64];
logevent("Requesting X11 forwarding");
x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
PKT_STR, proto, PKT_STR, data,
PKT_INT, 0,
PKT_END);
do { crReturnV; } while (!ispkt);
if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
logevent("X11 forwarding refused");
} else {
logevent("X11 forwarding enabled");
ssh_X11_fwd_enabled = TRUE;
}
}
if (!cfg.nopty) {
send_packet(SSH1_CMSG_REQUEST_PTY,
PKT_STR, cfg.termtype,
PKT_INT, rows, PKT_INT, cols,
PKT_INT, 0, PKT_INT, 0,
PKT_CHAR, 0,
PKT_END);
ssh_state = SSH_STATE_INTERMED;
do { crReturnV; } while (!ispkt);
if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
c_write("Server refused to allocate pty\r\n", 32);
ssh_editing = ssh_echoing = 1;
}
logevent("Allocated pty");
} else {
ssh_editing = ssh_echoing = 1;
}
if (cfg.compression) {
send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
do { crReturnV; } while (!ispkt);
if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
c_write("Server refused to compress\r\n", 32);
}
logevent("Started compression");
ssh1_compressing = TRUE;
zlib_compress_init();
zlib_decompress_init();
}
if (*cfg.remote_cmd)
send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END);
else
send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
logevent("Started session");
ssh_state = SSH_STATE_SESSION;
if (size_needed)
ssh_size();
if (eof_needed)
ssh_special(TS_EOF);
ldisc_send(NULL, 0); /* cause ldisc to notice changes */
ssh_send_ok = 1;
ssh_channels = newtree234(ssh_channelcmp);
while (1) {
crReturnV;
if (ispkt) {
if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
pktin.type == SSH1_SMSG_STDERR_DATA) {
long len = GET_32BIT(pktin.body);
from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
pktin.body+4, len);
} else if (pktin.type == SSH1_MSG_DISCONNECT) {
ssh_state = SSH_STATE_CLOSED;
logevent("Received disconnect request");
crReturnV;
} else if (pktin.type == SSH1_SMSG_X11_OPEN) {
/* Remote side is trying to open a channel to talk to our
* X-Server. Give them back a local channel number. */
unsigned i;
struct ssh_channel *c, *d;
enum234 e;
logevent("Received X11 connect request");
/* Refuse if X11 forwarding is disabled. */
if (!ssh_X11_fwd_enabled) {
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, GET_32BIT(pktin.body),
PKT_END);
logevent("Rejected X11 connect request");
} else {
c = smalloc(sizeof(struct ssh_channel));
if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) {
logevent("opening X11 forward connection failed");
sfree(c);
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, GET_32BIT(pktin.body),
PKT_END);
} else {
logevent("opening X11 forward connection succeeded");
for (i=1, d = first234(ssh_channels, &e); d; d = next234(&e)) {
if (d->localid > i)
break; /* found a free number */
i = d->localid + 1;
}
c->remoteid = GET_32BIT(pktin.body);
c->localid = i;
c->closes = 0;
c->type = CHAN_X11; /* identify channel type */
add234(ssh_channels, c);
send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
PKT_INT, c->remoteid, PKT_INT, c->localid,
PKT_END);
logevent("Opened X11 forward channel");
}
}
} else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
/* Remote side is trying to open a channel to talk to our
* agent. Give them back a local channel number. */
unsigned i;
struct ssh_channel *c;
enum234 e;
/* Refuse if agent forwarding is disabled. */
if (!ssh_agentfwd_enabled) {
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, GET_32BIT(pktin.body),
PKT_END);
} else {
i = 1;
for (c = first234(ssh_channels, &e); c; c = next234(&e)) {
if (c->localid > i)
break; /* found a free number */
i = c->localid + 1;
}
c = smalloc(sizeof(struct ssh_channel));
c->remoteid = GET_32BIT(pktin.body);
c->localid = i;
c->closes = 0;
c->type = CHAN_AGENT; /* identify channel type */
c->u.a.lensofar = 0;
add234(ssh_channels, c);
send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
PKT_INT, c->remoteid, PKT_INT, c->localid,
PKT_END);
}
} else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
/* Remote side closes a channel. */
unsigned i = GET_32BIT(pktin.body);
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (c) {
int closetype;
closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
if ((c->closes == 0) && (c->type == CHAN_X11)) {
logevent("X11 connection closed");
assert(c->u.x11.s != NULL);
x11_close(c->u.x11.s);
c->u.x11.s = NULL;
}
c->closes |= closetype;
if (c->closes == 3) {
del234(ssh_channels, c);
sfree(c);
}
}
} else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
/* Data sent down one of our channels. */
int i = GET_32BIT(pktin.body);
int len = GET_32BIT(pktin.body+4);
unsigned char *p = pktin.body+8;
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (c) {
switch(c->type) {
case CHAN_X11:
x11_send(c->u.x11.s, p, len);
break;
case CHAN_AGENT:
/* Data for an agent message. Buffer it. */
while (len > 0) {
if (c->u.a.lensofar < 4) {
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 = smalloc(c->u.a.totallen);
memcpy(c->u.a.message, c->u.a.msglen, 4);
}
if (c->u.a.lensofar >= 4 && len > 0) {
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, *sentreply;
int replylen;
agent_query(c->u.a.message, c->u.a.totallen,
&reply, &replylen);
if (reply)
sentreply = reply;
else {
/* Fake SSH_AGENT_FAILURE. */
sentreply = "\0\0\0\1\5";
replylen = 5;
}
send_packet(SSH1_MSG_CHANNEL_DATA,
PKT_INT, c->remoteid,
PKT_INT, replylen,
PKT_DATA, sentreply, replylen,
PKT_END);
if (reply)
sfree(reply);
sfree(c->u.a.message);
c->u.a.lensofar = 0;
}
}
break;
}
}
} else 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 if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
} else {
bombout(("Strange packet received: type %d", pktin.type));
crReturnV;
}
} else {
while (inlen > 0) {
int len = min(inlen, 512);
send_packet(SSH1_CMSG_STDIN_DATA,
PKT_INT, len, PKT_DATA, in, len, PKT_END);
in += len;
inlen -= len;
}
}
}
crFinishV;
}
/*
* Utility routine for decoding comma-separated strings in KEXINIT.
*/
static int in_commasep_string(char *needle, char *haystack, int haylen) {
int 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 */
}
}
/*
* SSH2 key creation method.
*/
static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, char *keyspace) {
SHA_State s;
/* First 20 bytes. */
SHA_Init(&s);
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);
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(unsigned char *in, int inlen, int ispkt)
{
static int i, len;
static char *str;
static Bignum e, f, K;
static const struct ssh_mac **maclist;
static int nmacs;
static const struct ssh_cipher *cscipher_tobe = NULL;
static const struct ssh_cipher *sccipher_tobe = NULL;
static const struct ssh_mac *csmac_tobe = NULL;
static const struct ssh_mac *scmac_tobe = NULL;
static const struct ssh_compress *cscomp_tobe = NULL;
static const struct ssh_compress *sccomp_tobe = NULL;
static char *hostkeydata, *sigdata, *keystr, *fingerprint;
static int hostkeylen, siglen;
static void *hkey; /* actual host key */
static unsigned char exchange_hash[20];
static unsigned char first_exchange_hash[20];
static unsigned char keyspace[40];
static const struct ssh_cipher *preferred_cipher;
static const struct ssh_compress *preferred_comp;
static int first_kex;
crBegin;
random_init();
first_kex = 1;
/*
* Set up the preferred cipher and compression.
*/
if (cfg.cipher == CIPHER_BLOWFISH) {
preferred_cipher = &ssh_blowfish_ssh2;
} else if (cfg.cipher == CIPHER_DES) {
logevent("Single DES not supported in SSH2; using 3DES");
preferred_cipher = &ssh_3des_ssh2;
} else if (cfg.cipher == CIPHER_3DES) {
preferred_cipher = &ssh_3des_ssh2;
} else {
/* Shouldn't happen, but we do want to initialise to _something_. */
preferred_cipher = &ssh_3des_ssh2;
}
if (cfg.compression)
preferred_comp = &ssh_zlib;
else
preferred_comp = &ssh_comp_none;
/*
* Be prepared to work around the buggy MAC problem.
*/
if (cfg.buggymac)
maclist = buggymacs, nmacs = lenof(buggymacs);
else
maclist = macs, nmacs = lenof(macs);
begin_key_exchange:
/*
* Construct and send our key exchange packet.
*/
ssh2_pkt_init(SSH2_MSG_KEXINIT);
for (i = 0; i < 16; i++)
ssh2_pkt_addbyte((unsigned char)random_byte());
/* List key exchange algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(kex_algs); i++) {
ssh2_pkt_addstring_str(kex_algs[i]->name);
if (i < lenof(kex_algs)-1)
ssh2_pkt_addstring_str(",");
}
/* List server host key algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(hostkey_algs); i++) {
ssh2_pkt_addstring_str(hostkey_algs[i]->name);
if (i < lenof(hostkey_algs)-1)
ssh2_pkt_addstring_str(",");
}
/* List client->server encryption algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(ciphers)+1; i++) {
const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
ssh2_pkt_addstring_str(c->name);
if (i < lenof(ciphers))
ssh2_pkt_addstring_str(",");
}
/* List server->client encryption algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(ciphers)+1; i++) {
const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
ssh2_pkt_addstring_str(c->name);
if (i < lenof(ciphers))
ssh2_pkt_addstring_str(",");
}
/* List client->server MAC algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < nmacs; i++) {
ssh2_pkt_addstring_str(maclist[i]->name);
if (i < nmacs-1)
ssh2_pkt_addstring_str(",");
}
/* List server->client MAC algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < nmacs; i++) {
ssh2_pkt_addstring_str(maclist[i]->name);
if (i < nmacs-1)
ssh2_pkt_addstring_str(",");
}
/* List client->server compression algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(compressions)+1; i++) {
const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
ssh2_pkt_addstring_str(c->name);
if (i < lenof(compressions))
ssh2_pkt_addstring_str(",");
}
/* List server->client compression algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(compressions)+1; i++) {
const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
ssh2_pkt_addstring_str(c->name);
if (i < lenof(compressions))
ssh2_pkt_addstring_str(",");
}
/* List client->server languages. Empty list. */
ssh2_pkt_addstring_start();
/* List server->client languages. Empty list. */
ssh2_pkt_addstring_start();
/* First KEX packet does _not_ follow, because we're not that brave. */
ssh2_pkt_addbool(FALSE);
/* Reserved. */
ssh2_pkt_adduint32(0);
exhash = exhashbase;
sha_string(&exhash, pktout.data+5, pktout.length-5);
ssh2_pkt_send();
if (!ispkt) crWaitUntil(ispkt);
sha_string(&exhash, pktin.data+5, pktin.length-5);
/*
* Now examine the other side's KEXINIT to see what we're up
* to.
*/
if (pktin.type != SSH2_MSG_KEXINIT) {
bombout(("expected key exchange packet from server"));
crReturn(0);
}
kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
pktin.savedpos += 16; /* skip garbage cookie */
ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
for (i = 0; i < lenof(kex_algs); i++) {
if (in_commasep_string(kex_algs[i]->name, str, len)) {
kex = kex_algs[i];
break;
}
}
ssh2_pkt_getstring(&str, &len); /* host key algorithms */
for (i = 0; i < lenof(hostkey_algs); i++) {
if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
hostkey = hostkey_algs[i];
break;
}
}
ssh2_pkt_getstring(&str, &len); /* client->server cipher */
for (i = 0; i < lenof(ciphers)+1; i++) {
const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
if (in_commasep_string(c->name, str, len)) {
cscipher_tobe = c;
break;
}
}
ssh2_pkt_getstring(&str, &len); /* server->client cipher */
for (i = 0; i < lenof(ciphers)+1; i++) {
const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
if (in_commasep_string(c->name, str, len)) {
sccipher_tobe = c;
break;
}
}
ssh2_pkt_getstring(&str, &len); /* client->server mac */
for (i = 0; i < nmacs; i++) {
if (in_commasep_string(maclist[i]->name, str, len)) {
csmac_tobe = maclist[i];
break;
}
}
ssh2_pkt_getstring(&str, &len); /* server->client mac */
for (i = 0; i < nmacs; i++) {
if (in_commasep_string(maclist[i]->name, str, len)) {
scmac_tobe = maclist[i];
break;
}
}
ssh2_pkt_getstring(&str, &len); /* client->server compression */
for (i = 0; i < lenof(compressions)+1; i++) {
const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
if (in_commasep_string(c->name, str, len)) {
cscomp_tobe = c;
break;
}
}
ssh2_pkt_getstring(&str, &len); /* server->client compression */
for (i = 0; i < lenof(compressions)+1; i++) {
const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
if (in_commasep_string(c->name, str, len)) {
sccomp_tobe = c;
break;
}
}
/*
* Currently we only support Diffie-Hellman and DSS, so let's
* bomb out if those aren't selected.
*/
if (kex != &ssh_diffiehellman || hostkey != &ssh_dss) {
bombout(("internal fault: chaos in SSH 2 transport layer"));
crReturn(0);
}
/*
* Now we begin the fun. Generate and send e for Diffie-Hellman.
*/
e = dh_create_e();
ssh2_pkt_init(SSH2_MSG_KEXDH_INIT);
ssh2_pkt_addmp(e);
ssh2_pkt_send();
crWaitUntil(ispkt);
if (pktin.type != SSH2_MSG_KEXDH_REPLY) {
bombout(("expected key exchange packet from server"));
crReturn(0);
}
ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
f = ssh2_pkt_getmp();
ssh2_pkt_getstring(&sigdata, &siglen);
K = dh_find_K(f);
sha_string(&exhash, hostkeydata, hostkeylen);
sha_mpint(&exhash, e);
sha_mpint(&exhash, f);
sha_mpint(&exhash, K);
SHA_Final(&exhash, exchange_hash);
#if 0
debug(("Exchange hash is:\r\n"));
for (i = 0; i < 20; i++)
debug((" %02x", exchange_hash[i]));
debug(("\r\n"));
#endif
hkey = hostkey->newkey(hostkeydata, hostkeylen);
if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
bombout(("Server failed host key check"));
crReturn(0);
}
/*
* Expect SSH2_MSG_NEWKEYS from server.
*/
crWaitUntil(ispkt);
if (pktin.type != SSH2_MSG_NEWKEYS) {
bombout(("expected new-keys packet from server"));
crReturn(0);
}
/*
* Authenticate remote host: verify host key. (We've already
* checked the signature of the exchange hash.)
*/
keystr = hostkey->fmtkey(hkey);
fingerprint = hostkey->fingerprint(hkey);
verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
keystr, fingerprint);
if (first_kex) { /* don't bother logging this in rekeys */
logevent("Host key fingerprint is:");
logevent(fingerprint);
}
sfree(fingerprint);
sfree(keystr);
hostkey->freekey(hkey);
/*
* Send SSH2_MSG_NEWKEYS.
*/
ssh2_pkt_init(SSH2_MSG_NEWKEYS);
ssh2_pkt_send();
/*
* Create and initialise session keys.
*/
cscipher = cscipher_tobe;
sccipher = sccipher_tobe;
csmac = csmac_tobe;
scmac = scmac_tobe;
cscomp = cscomp_tobe;
sccomp = sccomp_tobe;
cscomp->compress_init();
sccomp->decompress_init();
/*
* Set IVs after keys. Here we use the exchange hash from the
* _first_ key exchange.
*/
if (first_kex)
memcpy(first_exchange_hash, exchange_hash, sizeof(exchange_hash));
ssh2_mkkey(K, exchange_hash, first_exchange_hash, 'C', keyspace);
cscipher->setcskey(keyspace);
ssh2_mkkey(K, exchange_hash, first_exchange_hash, 'D', keyspace);
sccipher->setsckey(keyspace);
ssh2_mkkey(K, exchange_hash, first_exchange_hash, 'A', keyspace);
cscipher->setcsiv(keyspace);
ssh2_mkkey(K, exchange_hash, first_exchange_hash, 'B', keyspace);
sccipher->setsciv(keyspace);
ssh2_mkkey(K, exchange_hash, first_exchange_hash, 'E', keyspace);
csmac->setcskey(keyspace);
ssh2_mkkey(K, exchange_hash, first_exchange_hash, 'F', keyspace);
scmac->setsckey(keyspace);
/*
* 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 (!first_kex) {
crReturn(0);
}
first_kex = 0;
/*
* 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.
*/
do {
crReturn(1);
} while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT));
logevent("Server initiated key re-exchange");
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) {
if (c->v2.outbufsize <
c->v2.outbuflen + len) {
c->v2.outbufsize =
c->v2.outbuflen + len + 1024;
c->v2.outbuffer = srealloc(c->v2.outbuffer,
c->v2.outbufsize);
}
memcpy(c->v2.outbuffer + c->v2.outbuflen,
buf, len);
c->v2.outbuflen += len;
}
/*
* Attempt to send data on an SSH2 channel.
*/
static void ssh2_try_send(struct ssh_channel *c) {
while (c->v2.remwindow > 0 &&
c->v2.outbuflen > 0) {
unsigned len = c->v2.remwindow;
if (len > c->v2.outbuflen)
len = c->v2.outbuflen;
if (len > c->v2.remmaxpkt)
len = c->v2.remmaxpkt;
ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(c->v2.outbuffer, len);
ssh2_pkt_send();
c->v2.outbuflen -= len;
memmove(c->v2.outbuffer, c->v2.outbuffer+len,
c->v2.outbuflen);
c->v2.remwindow -= len;
}
}
/*
* Handle the SSH2 userauth and connection layers.
*/
static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
{
static unsigned long remote_winsize;
static unsigned long remote_maxpkt;
crBegin;
/*
* Request userauth protocol, and await a response to it.
*/
ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
ssh2_pkt_addstring("ssh-userauth");
ssh2_pkt_send();
crWaitUntilV(ispkt);
if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
bombout(("Server refused user authentication protocol"));
crReturnV;
}
/*
* FIXME: currently we support only password authentication.
* (This places us technically in violation of the SSH2 spec.
* We must fix this.)
*/
while (1) {
/*
* Get a username and a password.
*/
static char username[100];
static char password[100];
static int pos = 0;
static char c;
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
c_write("login as: ", 10);
ssh_send_ok = 1;
while (pos >= 0) {
crWaitUntilV(!ispkt);
while (inlen--) switch (c = *in++) {
case 10: case 13:
username[pos] = 0;
pos = -1;
break;
case 8: case 127:
if (pos > 0) {
c_write("\b \b", 3);
pos--;
}
break;
case 21: case 27:
while (pos > 0) {
c_write("\b \b", 3);
pos--;
}
break;
case 3: case 4:
random_save_seed();
exit(0);
break;
default:
if (((c >= ' ' && c <= '~') ||
((unsigned char)c >= 160)) && pos < 40) {
username[pos++] = c;
c_write(&c, 1);
}
break;
}
}
c_write("\r\n", 2);
username[strcspn(username, "\n\r")] = '\0';
} else {
char stuff[200];
strncpy(username, cfg.username, 99);
username[99] = '\0';
if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
sprintf(stuff, "Using username \"%s\".\r\n", username);
c_write(stuff, strlen(stuff));
}
}
if (ssh_get_password) {
char prompt[200];
sprintf(prompt, "%.90s@%.90s's password: ", username, savedhost);
if (!ssh_get_password(prompt, password, sizeof(password))) {
/*
* get_password failed to get a password (for
* example because one was supplied on the command
* line which has already failed to work).
* Terminate.
*/
logevent("No more passwords to try");
ssh_state = SSH_STATE_CLOSED;
crReturnV;
}
} else {
c_write("password: ", 10);
ssh_send_ok = 1;
pos = 0;
while (pos >= 0) {
crWaitUntilV(!ispkt);
while (inlen--) switch (c = *in++) {
case 10: case 13:
password[pos] = 0;
pos = -1;
break;
case 8: case 127:
if (pos > 0)
pos--;
break;
case 21: case 27:
pos = 0;
break;
case 3: case 4:
random_save_seed();
exit(0);
break;
default:
if (((c >= ' ' && c <= '~') ||
((unsigned char)c >= 160)) && pos < 40)
password[pos++] = c;
break;
}
}
c_write("\r\n", 2);
}
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(username);
ssh2_pkt_addstring("ssh-connection"); /* service requested */
ssh2_pkt_addstring("password");
ssh2_pkt_addbool(FALSE);
ssh2_pkt_addstring(password);
ssh2_pkt_send();
crWaitUntilV(ispkt);
if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) {
c_write("Access denied\r\n", 15);
logevent("Authentication refused");
} else
break;
}
/*
* 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.
*/
/*
* So now create a channel with a session in it.
*/
mainchan = smalloc(sizeof(struct ssh_channel));
mainchan->localid = 100; /* as good as any */
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
ssh2_pkt_addstring("session");
ssh2_pkt_adduint32(mainchan->localid);
ssh2_pkt_adduint32(0x8000UL); /* our window size */
ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
ssh2_pkt_send();
crWaitUntilV(ispkt);
if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
bombout(("Server refused to open a session"));
crReturnV;
/* FIXME: error data comes back in FAILURE packet */
}
if (ssh2_pkt_getuint32() != mainchan->localid) {
bombout(("Server's channel confirmation cited wrong channel"));
crReturnV;
}
mainchan->remoteid = ssh2_pkt_getuint32();
mainchan->type = CHAN_MAINSESSION;
mainchan->closes = 0;
mainchan->v2.remwindow = ssh2_pkt_getuint32();
mainchan->v2.remmaxpkt = ssh2_pkt_getuint32();
mainchan->v2.outbuffer = NULL;
mainchan->v2.outbuflen = mainchan->v2.outbufsize = 0;
ssh_channels = newtree234(ssh_channelcmp);
add234(ssh_channels, mainchan);
logevent("Opened channel for session");
/*
* Potentially enable X11 forwarding.
*/
if (cfg.x11_forward) {
char proto[20], data[64];
logevent("Requesting X11 forwarding");
x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid);
ssh2_pkt_addstring("x11-req");
ssh2_pkt_addbool(1); /* want reply */
ssh2_pkt_addbool(0); /* many connections */
ssh2_pkt_addstring(proto);
ssh2_pkt_addstring(data);
ssh2_pkt_adduint32(0); /* screen number */
ssh2_pkt_send();
do {
crWaitUntilV(ispkt);
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
c->v2.remwindow += ssh2_pkt_getuint32();
}
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Server got confused by X11 forwarding request"));
crReturnV;
}
logevent("X11 forwarding refused");
} else {
logevent("X11 forwarding enabled");
ssh_X11_fwd_enabled = TRUE;
}
}
/*
* Now allocate a pty for the session.
*/
if (!cfg.nopty) {
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
ssh2_pkt_addstring("pty-req");
ssh2_pkt_addbool(1); /* want reply */
ssh2_pkt_addstring(cfg.termtype);
ssh2_pkt_adduint32(cols);
ssh2_pkt_adduint32(rows);
ssh2_pkt_adduint32(0); /* pixel width */
ssh2_pkt_adduint32(0); /* pixel height */
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data("\0", 1);/* TTY_OP_END, no special options */
ssh2_pkt_send();
ssh_state = SSH_STATE_INTERMED;
do {
crWaitUntilV(ispkt);
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
c->v2.remwindow += ssh2_pkt_getuint32();
}
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Server got confused by pty request"));
crReturnV;
}
c_write("Server refused to allocate pty\r\n", 32);
ssh_editing = ssh_echoing = 1;
} else {
logevent("Allocated pty");
}
} else {
ssh_editing = ssh_echoing = 1;
}
/*
* Start a shell or a remote command.
*/
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
if (*cfg.remote_cmd) {
ssh2_pkt_addstring("exec");
ssh2_pkt_addbool(1); /* want reply */
ssh2_pkt_addstring(cfg.remote_cmd);
} else {
ssh2_pkt_addstring("shell");
ssh2_pkt_addbool(1); /* want reply */
}
ssh2_pkt_send();
do {
crWaitUntilV(ispkt);
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
c->v2.remwindow += ssh2_pkt_getuint32();
}
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Server got confused by shell/command request"));
crReturnV;
}
bombout(("Server refused to start a shell/command"));
crReturnV;
} else {
logevent("Started a shell/command");
}
ssh_state = SSH_STATE_SESSION;
if (size_needed)
ssh_size();
if (eof_needed)
ssh_special(TS_EOF);
/*
* Transfer data!
*/
ldisc_send(NULL, 0); /* cause ldisc to notice changes */
ssh_send_ok = 1;
while (1) {
static int try_send;
crReturnV;
try_send = FALSE;
if (ispkt) {
if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
char *data;
int length;
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
continue; /* extended but not stderr */
ssh2_pkt_getstring(&data, &length);
if (data) {
switch (c->type) {
case CHAN_MAINSESSION:
from_backend(pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA,
data, length);
break;
case CHAN_X11:
x11_send(c->u.x11.s, data, length);
break;
}
/*
* Enlarge the window again at the remote
* side, just in case it ever runs down and
* they fail to send us any more data.
*/
ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_adduint32(length);
ssh2_pkt_send();
}
} else if (pktin.type == SSH2_MSG_DISCONNECT) {
ssh_state = SSH_STATE_CLOSED;
logevent("Received disconnect message");
crReturnV;
} else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
continue; /* exit status et al; ignore (FIXME?) */
} else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* 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 (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
enum234 e;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
if (c->closes == 0) {
ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_send();
}
/* Do pre-close processing on the channel. */
switch (c->type) {
case CHAN_MAINSESSION:
break; /* nothing to see here, move along */
case CHAN_X11:
break;
}
del234(ssh_channels, c);
sfree(c->v2.outbuffer);
sfree(c);
/*
* See if that was the last channel left open.
*/
c = first234(ssh_channels, &e);
if (!c) {
logevent("All channels closed. Disconnecting");
ssh2_pkt_init(SSH2_MSG_DISCONNECT);
ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
ssh2_pkt_addstring("All open channels closed");
ssh2_pkt_addstring("en"); /* language tag */
ssh2_pkt_send();
ssh_state = SSH_STATE_CLOSED;
crReturnV;
}
continue; /* remote sends close; ignore (FIXME) */
} else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
mainchan->v2.remwindow += ssh2_pkt_getuint32();
try_send = TRUE;
} else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
char *type;
int typelen;
char *error = NULL;
struct ssh_channel *c;
ssh2_pkt_getstring(&type, &typelen);
c = smalloc(sizeof(struct ssh_channel));
if (typelen == 3 && !memcmp(type, "x11", 3)) {
if (!ssh_X11_fwd_enabled)
error = "X11 forwarding is not enabled";
else if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) {
error = "Unable to open an X11 connection";
} else {
c->type = CHAN_X11;
}
} else {
error = "Unsupported channel type requested";
}
c->remoteid = ssh2_pkt_getuint32();
if (error) {
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED);
ssh2_pkt_addstring(error);
ssh2_pkt_addstring("en"); /* language tag */
ssh2_pkt_send();
sfree(c);
} else {
struct ssh_channel *d;
unsigned i;
enum234 e;
for (i=1, d = first234(ssh_channels, &e); d;
d = next234(&e)) {
if (d->localid > i)
break; /* found a free number */
i = d->localid + 1;
}
c->localid = i;
c->closes = 0;
c->v2.remwindow = ssh2_pkt_getuint32();
c->v2.remmaxpkt = ssh2_pkt_getuint32();
c->v2.outbuffer = NULL;
c->v2.outbuflen = c->v2.outbufsize = 0;
add234(ssh_channels, c);
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_adduint32(c->localid);
ssh2_pkt_adduint32(0x8000UL); /* our window size */
ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
ssh2_pkt_send();
}
} else {
bombout(("Strange packet received: type %d", pktin.type));
crReturnV;
}
} else {
/*
* We have spare data. Add it to the channel buffer.
*/
ssh2_add_channel_data(mainchan, in, inlen);
try_send = TRUE;
}
if (try_send) {
enum234 e;
struct ssh_channel *c;
/*
* Try to send data on all channels if we can.
*/
for (c = first234(ssh_channels, &e); c; c = next234(&e))
ssh2_try_send(c);
}
}
crFinishV;
}
/*
* Handle the top-level SSH2 protocol.
*/
static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
{
if (do_ssh2_transport(in, inlen, ispkt) == 0)
return;
do_ssh2_authconn(in, inlen, ispkt);
}
/*
* Called to set up the connection.
*
* Returns an error message, or NULL on success.
*/
static char *ssh_init (char *host, int port, char **realhost) {
char *p;
#ifdef MSCRYPTOAPI
if(crypto_startup() == 0)
return "Microsoft high encryption pack not installed!";
#endif
ssh_send_ok = 0;
ssh_editing = 0;
ssh_echoing = 0;
p = connect_to_host(host, port, realhost);
if (p != NULL)
return p;
return NULL;
}
/*
* Called to send data down the Telnet connection.
*/
static void ssh_send (char *buf, int len) {
if (s == NULL || ssh_protocol == NULL)
return;
ssh_protocol(buf, len, 0);
}
/*
* Called to set the size of the window from SSH's POV.
*/
static void ssh_size(void) {
switch (ssh_state) {
case SSH_STATE_BEFORE_SIZE:
case SSH_STATE_PREPACKET:
case SSH_STATE_CLOSED:
break; /* do nothing */
case SSH_STATE_INTERMED:
size_needed = TRUE; /* buffer for later */
break;
case SSH_STATE_SESSION:
if (!cfg.nopty) {
if (ssh_version == 1) {
send_packet(SSH1_CMSG_WINDOW_SIZE,
PKT_INT, rows, PKT_INT, cols,
PKT_INT, 0, PKT_INT, 0, PKT_END);
} else {
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid);
ssh2_pkt_addstring("window-change");
ssh2_pkt_addbool(0);
ssh2_pkt_adduint32(cols);
ssh2_pkt_adduint32(rows);
ssh2_pkt_adduint32(0);
ssh2_pkt_adduint32(0);
ssh2_pkt_send();
}
}
break;
}
}
/*
* 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 (Telnet_Special code) {
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)
eof_needed = TRUE;
return;
}
if (ssh_version == 1) {
send_packet(SSH1_CMSG_EOF, PKT_END);
} else {
ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
ssh2_pkt_adduint32(mainchan->remoteid);
ssh2_pkt_send();
}
logevent("Sent EOF message");
} else if (code == TS_PING) {
if (ssh_state == SSH_STATE_CLOSED || ssh_state == SSH_STATE_PREPACKET)
return;
if (ssh_version == 1) {
send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
} else {
ssh2_pkt_init(SSH2_MSG_IGNORE);
ssh2_pkt_addstring_start();
ssh2_pkt_send();
}
} else {
/* do nothing */
}
}
static Socket ssh_socket(void) { return s; }
static int ssh_sendok(void) { return ssh_send_ok; }
static int ssh_ldisc(int option) {
if (option == LD_ECHO) return ssh_echoing;
if (option == LD_EDIT) return ssh_editing;
return FALSE;
}
Backend ssh_backend = {
ssh_init,
ssh_send,
ssh_size,
ssh_special,
ssh_socket,
ssh_sendok,
ssh_ldisc,
22
};
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