зеркало из https://github.com/github/putty.git
556 строки
14 KiB
C
556 строки
14 KiB
C
/*
|
|
* SSH port forwarding.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
#include "putty.h"
|
|
#include "ssh.h"
|
|
|
|
#ifndef FALSE
|
|
#define FALSE 0
|
|
#endif
|
|
#ifndef TRUE
|
|
#define TRUE 1
|
|
#endif
|
|
|
|
struct PFwdPrivate {
|
|
const struct plug_function_table *fn;
|
|
/* the above variable absolutely *must* be the first in this structure */
|
|
void *c; /* (channel) data used by ssh.c */
|
|
void *backhandle; /* instance of SSH backend itself */
|
|
/* Note that backhandle need not be filled in if c is non-NULL */
|
|
Socket s;
|
|
int throttled, throttle_override;
|
|
int ready;
|
|
/*
|
|
* `dynamic' does double duty. It's set to 0 for an ordinary
|
|
* forwarded port, and nonzero for SOCKS-style dynamic port
|
|
* forwarding; but it also represents the state of the SOCKS
|
|
* exchange.
|
|
*/
|
|
int dynamic;
|
|
/*
|
|
* `hostname' and `port' are the real hostname and port, once
|
|
* we know what we're connecting to; they're unused for this
|
|
* purpose while conducting a local SOCKS exchange, which means
|
|
* we can also use them as a buffer and pointer for reading
|
|
* data from the SOCKS client.
|
|
*/
|
|
char hostname[256+8];
|
|
int port;
|
|
/*
|
|
* When doing dynamic port forwarding, we can receive
|
|
* connection data before we are actually able to send it; so
|
|
* we may have to temporarily hold some in a dynamically
|
|
* allocated buffer here.
|
|
*/
|
|
void *buffer;
|
|
int buflen;
|
|
};
|
|
|
|
static void pfd_log(Plug plug, int type, SockAddr addr, int port,
|
|
const char *error_msg, int error_code)
|
|
{
|
|
/* we have to dump these since we have no interface to logging.c */
|
|
}
|
|
|
|
static int pfd_closing(Plug plug, const char *error_msg, int error_code,
|
|
int calling_back)
|
|
{
|
|
struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
|
|
|
|
/*
|
|
* We have no way to communicate down the forwarded connection,
|
|
* so if an error occurred on the socket, we just ignore it
|
|
* and treat it like a proper close.
|
|
*/
|
|
if (pr->c)
|
|
sshfwd_close(pr->c);
|
|
pfd_close(pr->s);
|
|
return 1;
|
|
}
|
|
|
|
static int pfd_receive(Plug plug, int urgent, char *data, int len)
|
|
{
|
|
struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
|
|
if (pr->dynamic) {
|
|
while (len--) {
|
|
/*
|
|
* Throughout SOCKS negotiation, "hostname" is re-used as a
|
|
* random protocol buffer with "port" storing the length.
|
|
*/
|
|
if (pr->port >= lenof(pr->hostname)) {
|
|
/* Request too long. */
|
|
if ((pr->dynamic >> 12) == 4) {
|
|
/* Send back a SOCKS 4 error before closing. */
|
|
char data[8];
|
|
memset(data, 0, sizeof(data));
|
|
data[1] = 91; /* generic `request rejected' */
|
|
sk_write(pr->s, data, 8);
|
|
}
|
|
pfd_close(pr->s);
|
|
return 1;
|
|
}
|
|
pr->hostname[pr->port++] = *data++;
|
|
|
|
/*
|
|
* Now check what's in the buffer to see if it's a
|
|
* valid and complete message in the SOCKS exchange.
|
|
*/
|
|
if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 4) &&
|
|
pr->hostname[0] == 4) {
|
|
/*
|
|
* SOCKS 4.
|
|
*/
|
|
if (pr->dynamic == 1)
|
|
pr->dynamic = 0x4000;
|
|
if (pr->port < 2) continue;/* don't have command code yet */
|
|
if (pr->hostname[1] != 1) {
|
|
/* Not CONNECT. */
|
|
/* Send back a SOCKS 4 error before closing. */
|
|
char data[8];
|
|
memset(data, 0, sizeof(data));
|
|
data[1] = 91; /* generic `request rejected' */
|
|
sk_write(pr->s, data, 8);
|
|
pfd_close(pr->s);
|
|
return 1;
|
|
}
|
|
if (pr->port <= 8) continue; /* haven't started user/hostname */
|
|
if (pr->hostname[pr->port-1] != 0)
|
|
continue; /* haven't _finished_ user/hostname */
|
|
/*
|
|
* Now we have a full SOCKS 4 request. Check it to
|
|
* see if it's a SOCKS 4A request.
|
|
*/
|
|
if (pr->hostname[4] == 0 && pr->hostname[5] == 0 &&
|
|
pr->hostname[6] == 0 && pr->hostname[7] != 0) {
|
|
/*
|
|
* It's SOCKS 4A. So if we haven't yet
|
|
* collected the host name, we should continue
|
|
* waiting for data in order to do so; if we
|
|
* have, we can go ahead.
|
|
*/
|
|
int len;
|
|
if (pr->dynamic == 0x4000) {
|
|
pr->dynamic = 0x4001;
|
|
pr->port = 8; /* reset buffer to overwrite name */
|
|
continue;
|
|
}
|
|
pr->hostname[0] = 0; /* reply version code */
|
|
pr->hostname[1] = 90; /* request granted */
|
|
sk_write(pr->s, pr->hostname, 8);
|
|
len= pr->port - 8;
|
|
pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);
|
|
memmove(pr->hostname, pr->hostname + 8, len);
|
|
goto connect;
|
|
} else {
|
|
/*
|
|
* It's SOCKS 4, which means we should format
|
|
* the IP address into the hostname string and
|
|
* then just go.
|
|
*/
|
|
pr->hostname[0] = 0; /* reply version code */
|
|
pr->hostname[1] = 90; /* request granted */
|
|
sk_write(pr->s, pr->hostname, 8);
|
|
pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);
|
|
sprintf(pr->hostname, "%d.%d.%d.%d",
|
|
(unsigned char)pr->hostname[4],
|
|
(unsigned char)pr->hostname[5],
|
|
(unsigned char)pr->hostname[6],
|
|
(unsigned char)pr->hostname[7]);
|
|
goto connect;
|
|
}
|
|
}
|
|
|
|
if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 5) &&
|
|
pr->hostname[0] == 5) {
|
|
/*
|
|
* SOCKS 5.
|
|
*/
|
|
if (pr->dynamic == 1)
|
|
pr->dynamic = 0x5000;
|
|
|
|
if (pr->dynamic == 0x5000) {
|
|
int i, method;
|
|
char data[2];
|
|
/*
|
|
* We're receiving a set of method identifiers.
|
|
*/
|
|
if (pr->port < 2) continue;/* no method count yet */
|
|
if (pr->port < 2 + (unsigned char)pr->hostname[1])
|
|
continue; /* no methods yet */
|
|
method = 0xFF; /* invalid */
|
|
for (i = 0; i < (unsigned char)pr->hostname[1]; i++)
|
|
if (pr->hostname[2+i] == 0) {
|
|
method = 0;/* no auth */
|
|
break;
|
|
}
|
|
data[0] = 5;
|
|
data[1] = method;
|
|
sk_write(pr->s, data, 2);
|
|
pr->dynamic = 0x5001;
|
|
pr->port = 0; /* re-empty the buffer */
|
|
continue;
|
|
}
|
|
|
|
if (pr->dynamic == 0x5001) {
|
|
/*
|
|
* We're receiving a SOCKS request.
|
|
*/
|
|
unsigned char reply[10]; /* SOCKS5 atyp=1 reply */
|
|
int atype, alen = 0;
|
|
|
|
/*
|
|
* Pre-fill reply packet.
|
|
* In all cases, we set BND.{HOST,ADDR} to 0.0.0.0:0
|
|
* (atyp=1) in the reply; if we succeed, we don't know
|
|
* the right answers, and if we fail, they should be
|
|
* ignored.
|
|
*/
|
|
memset(reply, 0, lenof(reply));
|
|
reply[0] = 5; /* VER */
|
|
reply[3] = 1; /* ATYP = 1 (IPv4, 0.0.0.0:0) */
|
|
|
|
if (pr->port < 6) continue;
|
|
atype = (unsigned char)pr->hostname[3];
|
|
if (atype == 1) /* IPv4 address */
|
|
alen = 4;
|
|
if (atype == 4) /* IPv6 address */
|
|
alen = 16;
|
|
if (atype == 3) /* domain name has leading length */
|
|
alen = 1 + (unsigned char)pr->hostname[4];
|
|
if (pr->port < 6 + alen) continue;
|
|
if (pr->hostname[1] != 1 || pr->hostname[2] != 0) {
|
|
/* Not CONNECT or reserved field nonzero - error */
|
|
reply[1] = 1; /* generic failure */
|
|
sk_write(pr->s, (char *) reply, lenof(reply));
|
|
pfd_close(pr->s);
|
|
return 1;
|
|
}
|
|
/*
|
|
* Now we have a viable connect request. Switch
|
|
* on atype.
|
|
*/
|
|
pr->port = GET_16BIT_MSB_FIRST(pr->hostname+4+alen);
|
|
if (atype == 1) {
|
|
/* REP=0 (success) already */
|
|
sk_write(pr->s, (char *) reply, lenof(reply));
|
|
sprintf(pr->hostname, "%d.%d.%d.%d",
|
|
(unsigned char)pr->hostname[4],
|
|
(unsigned char)pr->hostname[5],
|
|
(unsigned char)pr->hostname[6],
|
|
(unsigned char)pr->hostname[7]);
|
|
goto connect;
|
|
} else if (atype == 3) {
|
|
/* REP=0 (success) already */
|
|
sk_write(pr->s, (char *) reply, lenof(reply));
|
|
memmove(pr->hostname, pr->hostname + 5, alen-1);
|
|
pr->hostname[alen-1] = '\0';
|
|
goto connect;
|
|
} else {
|
|
/*
|
|
* Unknown address type. (FIXME: support IPv6!)
|
|
*/
|
|
reply[1] = 8; /* atype not supported */
|
|
sk_write(pr->s, (char *) reply, lenof(reply));
|
|
pfd_close(pr->s);
|
|
return 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we get here without either having done `continue'
|
|
* or `goto connect', it must be because there is no
|
|
* sensible interpretation of what's in our buffer. So
|
|
* close the connection rudely.
|
|
*/
|
|
pfd_close(pr->s);
|
|
return 1;
|
|
}
|
|
return 1;
|
|
|
|
/*
|
|
* We come here when we're ready to make an actual
|
|
* connection.
|
|
*/
|
|
connect:
|
|
|
|
pr->c = new_sock_channel(pr->backhandle, pr->s);
|
|
if (pr->c == NULL) {
|
|
pfd_close(pr->s);
|
|
return 1;
|
|
} else {
|
|
/* asks to forward to the specified host/port for this */
|
|
ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
|
|
}
|
|
pr->dynamic = 0;
|
|
|
|
/*
|
|
* Now freeze the socket until the SSH server confirms the
|
|
* connection.
|
|
*/
|
|
sk_set_frozen(pr->s, 1);
|
|
/*
|
|
* If there's any data remaining in our current buffer,
|
|
* save it to be sent on pfd_confirm().
|
|
*/
|
|
if (len > 0) {
|
|
pr->buffer = snewn(len, char);
|
|
memcpy(pr->buffer, data, len);
|
|
pr->buflen = len;
|
|
}
|
|
}
|
|
if (pr->ready) {
|
|
if (sshfwd_write(pr->c, data, len) > 0) {
|
|
pr->throttled = 1;
|
|
sk_set_frozen(pr->s, 1);
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static void pfd_sent(Plug plug, int bufsize)
|
|
{
|
|
struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
|
|
|
|
if (pr->c)
|
|
sshfwd_unthrottle(pr->c, bufsize);
|
|
}
|
|
|
|
/*
|
|
* Called when receiving a PORT OPEN from the server
|
|
*/
|
|
const char *pfd_newconnect(Socket *s, char *hostname, int port,
|
|
void *c, const Config *cfg, int addressfamily)
|
|
{
|
|
static const struct plug_function_table fn_table = {
|
|
pfd_log,
|
|
pfd_closing,
|
|
pfd_receive,
|
|
pfd_sent,
|
|
NULL
|
|
};
|
|
|
|
SockAddr addr;
|
|
const char *err;
|
|
char *dummy_realhost;
|
|
struct PFwdPrivate *pr;
|
|
|
|
/*
|
|
* Try to find host.
|
|
*/
|
|
addr = name_lookup(hostname, port, &dummy_realhost, cfg, addressfamily);
|
|
if ((err = sk_addr_error(addr)) != NULL) {
|
|
sk_addr_free(addr);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Open socket.
|
|
*/
|
|
pr = snew(struct PFwdPrivate);
|
|
pr->buffer = NULL;
|
|
pr->fn = &fn_table;
|
|
pr->throttled = pr->throttle_override = 0;
|
|
pr->ready = 1;
|
|
pr->c = c;
|
|
pr->backhandle = NULL; /* we shouldn't need this */
|
|
pr->dynamic = 0;
|
|
|
|
pr->s = *s = new_connection(addr, dummy_realhost, port,
|
|
0, 1, 0, 0, (Plug) pr, cfg);
|
|
if ((err = sk_socket_error(*s)) != NULL) {
|
|
sfree(pr);
|
|
return err;
|
|
}
|
|
|
|
sk_set_private_ptr(*s, pr);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
called when someone connects to the local port
|
|
*/
|
|
|
|
static int pfd_accepting(Plug p, OSSocket sock)
|
|
{
|
|
static const struct plug_function_table fn_table = {
|
|
pfd_log,
|
|
pfd_closing,
|
|
pfd_receive,
|
|
pfd_sent,
|
|
NULL
|
|
};
|
|
struct PFwdPrivate *pr, *org;
|
|
Socket s;
|
|
const char *err;
|
|
|
|
org = (struct PFwdPrivate *)p;
|
|
pr = snew(struct PFwdPrivate);
|
|
pr->buffer = NULL;
|
|
pr->fn = &fn_table;
|
|
|
|
pr->c = NULL;
|
|
pr->backhandle = org->backhandle;
|
|
|
|
pr->s = s = sk_register(sock, (Plug) pr);
|
|
if ((err = sk_socket_error(s)) != NULL) {
|
|
sfree(pr);
|
|
return err != NULL;
|
|
}
|
|
|
|
sk_set_private_ptr(s, pr);
|
|
|
|
pr->throttled = pr->throttle_override = 0;
|
|
pr->ready = 0;
|
|
|
|
if (org->dynamic) {
|
|
pr->dynamic = 1;
|
|
pr->port = 0; /* "hostname" buffer is so far empty */
|
|
sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */
|
|
} else {
|
|
pr->dynamic = 0;
|
|
strcpy(pr->hostname, org->hostname);
|
|
pr->port = org->port;
|
|
pr->c = new_sock_channel(org->backhandle, s);
|
|
|
|
if (pr->c == NULL) {
|
|
sfree(pr);
|
|
return 1;
|
|
} else {
|
|
/* asks to forward to the specified host/port for this */
|
|
ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* Add a new forwarding from port -> desthost:destport
|
|
sets up a listener on the local machine on (srcaddr:)port
|
|
*/
|
|
const char *pfd_addforward(char *desthost, int destport, char *srcaddr,
|
|
int port, void *backhandle, const Config *cfg,
|
|
void **sockdata, int address_family)
|
|
{
|
|
static const struct plug_function_table fn_table = {
|
|
pfd_log,
|
|
pfd_closing,
|
|
pfd_receive, /* should not happen... */
|
|
pfd_sent, /* also should not happen */
|
|
pfd_accepting
|
|
};
|
|
|
|
const char *err;
|
|
struct PFwdPrivate *pr;
|
|
Socket s;
|
|
|
|
/*
|
|
* Open socket.
|
|
*/
|
|
pr = snew(struct PFwdPrivate);
|
|
pr->buffer = NULL;
|
|
pr->fn = &fn_table;
|
|
pr->c = NULL;
|
|
if (desthost) {
|
|
strcpy(pr->hostname, desthost);
|
|
pr->port = destport;
|
|
pr->dynamic = 0;
|
|
} else
|
|
pr->dynamic = 1;
|
|
pr->throttled = pr->throttle_override = 0;
|
|
pr->ready = 0;
|
|
pr->backhandle = backhandle;
|
|
|
|
pr->s = s = new_listener(srcaddr, port, (Plug) pr,
|
|
!cfg->lport_acceptall, cfg, address_family);
|
|
if ((err = sk_socket_error(s)) != NULL) {
|
|
sfree(pr);
|
|
return err;
|
|
}
|
|
|
|
sk_set_private_ptr(s, pr);
|
|
|
|
*sockdata = (void *)s;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
void pfd_close(Socket s)
|
|
{
|
|
struct PFwdPrivate *pr;
|
|
|
|
if (!s)
|
|
return;
|
|
|
|
pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
|
|
|
|
sfree(pr->buffer);
|
|
sfree(pr);
|
|
|
|
sk_close(s);
|
|
}
|
|
|
|
/*
|
|
* Terminate a listener.
|
|
*/
|
|
void pfd_terminate(void *sv)
|
|
{
|
|
pfd_close((Socket)sv);
|
|
}
|
|
|
|
void pfd_unthrottle(Socket s)
|
|
{
|
|
struct PFwdPrivate *pr;
|
|
if (!s)
|
|
return;
|
|
pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
|
|
|
|
pr->throttled = 0;
|
|
sk_set_frozen(s, pr->throttled || pr->throttle_override);
|
|
}
|
|
|
|
void pfd_override_throttle(Socket s, int enable)
|
|
{
|
|
struct PFwdPrivate *pr;
|
|
if (!s)
|
|
return;
|
|
pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
|
|
|
|
pr->throttle_override = enable;
|
|
sk_set_frozen(s, pr->throttled || pr->throttle_override);
|
|
}
|
|
|
|
/*
|
|
* Called to send data down the raw connection.
|
|
*/
|
|
int pfd_send(Socket s, char *data, int len)
|
|
{
|
|
if (s == NULL)
|
|
return 0;
|
|
return sk_write(s, data, len);
|
|
}
|
|
|
|
|
|
void pfd_confirm(Socket s)
|
|
{
|
|
struct PFwdPrivate *pr;
|
|
|
|
if (s == NULL)
|
|
return;
|
|
|
|
pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
|
|
pr->ready = 1;
|
|
sk_set_frozen(s, 0);
|
|
sk_write(s, NULL, 0);
|
|
if (pr->buffer) {
|
|
sshfwd_write(pr->c, pr->buffer, pr->buflen);
|
|
sfree(pr->buffer);
|
|
pr->buffer = NULL;
|
|
}
|
|
}
|