diff options
Diffstat (limited to 'tools/plink/portfwd.c')
| -rw-r--r-- | tools/plink/portfwd.c | 1203 |
1 files changed, 636 insertions, 567 deletions
diff --git a/tools/plink/portfwd.c b/tools/plink/portfwd.c index 545dfecd4..e3e63e39a 100644 --- a/tools/plink/portfwd.c +++ b/tools/plink/portfwd.c @@ -1,567 +1,636 @@ -/*
- * 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;
-
- if (error_msg) {
- /*
- * Socket error. Slam the connection instantly shut.
- */
- sshfwd_unclean_close(pr->c);
- } else {
- /*
- * Ordinary EOF received on socket. Send an EOF on the SSH
- * channel.
- */
- if (pr->c)
- sshfwd_write_eof(pr->c);
- }
-
- 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:
-
- /*
- * Freeze the socket until the SSH server confirms the
- * connection.
- */
- sk_set_frozen(pr->s, 1);
-
- 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;
-
- /*
- * 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, Conf *conf, 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, conf, 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, conf);
- 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, Conf *conf,
- 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,
- !conf_get_int(conf, CONF_lport_acceptall),
- conf, 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_send_eof(Socket s)
-{
- sk_write_eof(s);
-}
-
-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;
- }
-}
+/* + * 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 PortForwarding { + const struct plug_function_table *fn; + /* the above variable absolutely *must* be the first in this structure */ + struct ssh_channel *c; /* channel structure held 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 the nonzero values are also a state machine + * tracking where the SOCKS exchange has got to. + */ + int dynamic; + /* + * `hostname' and `port' are the real hostname and port, once + * we know what we're connecting to. + */ + char *hostname; + int port; + /* + * `socksbuf' is the buffer we use to accumulate a SOCKS request. + */ + char *socksbuf; + int sockslen, sockssize; + /* + * 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; +}; + +struct PortListener { + const struct plug_function_table *fn; + /* the above variable absolutely *must* be the first in this structure */ + void *backhandle; /* instance of SSH backend itself */ + Socket s; + /* + * `dynamic' is set to 0 for an ordinary forwarded port, and + * nonzero for SOCKS-style dynamic port forwarding. + */ + int dynamic; + /* + * `hostname' and `port' are the real hostname and port, for + * ordinary forwardings. + */ + char *hostname; + int port; +}; + +static struct PortForwarding *new_portfwd_state(void) +{ + struct PortForwarding *pf = snew(struct PortForwarding); + pf->hostname = NULL; + pf->socksbuf = NULL; + pf->sockslen = pf->sockssize = 0; + pf->buffer = NULL; + return pf; +} + +static void free_portfwd_state(struct PortForwarding *pf) +{ + if (!pf) + return; + sfree(pf->hostname); + sfree(pf->socksbuf); + sfree(pf->buffer); + sfree(pf); +} + +static struct PortListener *new_portlistener_state(void) +{ + struct PortListener *pl = snew(struct PortListener); + pl->hostname = NULL; + return pl; +} + +static void free_portlistener_state(struct PortListener *pl) +{ + if (!pl) + return; + sfree(pl->hostname); + sfree(pl); +} + +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 void pfl_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 PortForwarding *pf = (struct PortForwarding *) plug; + + if (error_msg) { + /* + * Socket error. Slam the connection instantly shut. + */ + if (pf->c) { + sshfwd_unclean_close(pf->c, error_msg); + } else { + /* + * We might not have an SSH channel, if a socket error + * occurred during SOCKS negotiation. If not, we must + * clean ourself up without sshfwd_unclean_close's call + * back to pfd_close. + */ + pfd_close(pf); + } + } else { + /* + * Ordinary EOF received on socket. Send an EOF on the SSH + * channel. + */ + if (pf->c) + sshfwd_write_eof(pf->c); + } + + return 1; +} + +static int pfl_closing(Plug plug, const char *error_msg, int error_code, + int calling_back) +{ + struct PortListener *pl = (struct PortListener *) plug; + pfl_terminate(pl); + return 1; +} + +static int pfd_receive(Plug plug, int urgent, char *data, int len) +{ + struct PortForwarding *pf = (struct PortForwarding *) plug; + if (pf->dynamic) { + while (len--) { + if (pf->sockslen >= pf->sockssize) { + pf->sockssize = pf->sockslen * 5 / 4 + 256; + pf->socksbuf = sresize(pf->socksbuf, pf->sockssize, char); + } + pf->socksbuf[pf->sockslen++] = *data++; + + /* + * Now check what's in the buffer to see if it's a + * valid and complete message in the SOCKS exchange. + */ + if ((pf->dynamic == 1 || (pf->dynamic >> 12) == 4) && + pf->socksbuf[0] == 4) { + /* + * SOCKS 4. + */ + if (pf->dynamic == 1) + pf->dynamic = 0x4000; + if (pf->sockslen < 2) + continue; /* don't have command code yet */ + if (pf->socksbuf[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(pf->s, data, 8); + pfd_close(pf); + return 1; + } + if (pf->sockslen <= 8) + continue; /* haven't started user/hostname */ + if (pf->socksbuf[pf->sockslen-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 (pf->socksbuf[4] == 0 && pf->socksbuf[5] == 0 && + pf->socksbuf[6] == 0 && pf->socksbuf[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 (pf->dynamic == 0x4000) { + pf->dynamic = 0x4001; + pf->sockslen = 8; /* reset buffer to overwrite name */ + continue; + } + pf->socksbuf[0] = 0; /* reply version code */ + pf->socksbuf[1] = 90; /* request granted */ + sk_write(pf->s, pf->socksbuf, 8); + len = pf->sockslen - 8; + pf->port = GET_16BIT_MSB_FIRST(pf->socksbuf+2); + pf->hostname = snewn(len+1, char); + pf->hostname[len] = '\0'; + memcpy(pf->hostname, pf->socksbuf + 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. + */ + pf->socksbuf[0] = 0; /* reply version code */ + pf->socksbuf[1] = 90; /* request granted */ + sk_write(pf->s, pf->socksbuf, 8); + pf->port = GET_16BIT_MSB_FIRST(pf->socksbuf+2); + pf->hostname = dupprintf("%d.%d.%d.%d", + (unsigned char)pf->socksbuf[4], + (unsigned char)pf->socksbuf[5], + (unsigned char)pf->socksbuf[6], + (unsigned char)pf->socksbuf[7]); + goto connect; + } + } + + if ((pf->dynamic == 1 || (pf->dynamic >> 12) == 5) && + pf->socksbuf[0] == 5) { + /* + * SOCKS 5. + */ + if (pf->dynamic == 1) + pf->dynamic = 0x5000; + + if (pf->dynamic == 0x5000) { + int i, method; + char data[2]; + /* + * We're receiving a set of method identifiers. + */ + if (pf->sockslen < 2) + continue; /* no method count yet */ + if (pf->sockslen < 2 + (unsigned char)pf->socksbuf[1]) + continue; /* no methods yet */ + method = 0xFF; /* invalid */ + for (i = 0; i < (unsigned char)pf->socksbuf[1]; i++) + if (pf->socksbuf[2+i] == 0) { + method = 0;/* no auth */ + break; + } + data[0] = 5; + data[1] = method; + sk_write(pf->s, data, 2); + pf->dynamic = 0x5001; + pf->sockslen = 0; /* re-empty the buffer */ + continue; + } + + if (pf->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 (pf->sockslen < 6) continue; + atype = (unsigned char)pf->socksbuf[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)pf->socksbuf[4]; + if (pf->sockslen < 6 + alen) continue; + if (pf->socksbuf[1] != 1 || pf->socksbuf[2] != 0) { + /* Not CONNECT or reserved field nonzero - error */ + reply[1] = 1; /* generic failure */ + sk_write(pf->s, (char *) reply, lenof(reply)); + pfd_close(pf); + return 1; + } + /* + * Now we have a viable connect request. Switch + * on atype. + */ + pf->port = GET_16BIT_MSB_FIRST(pf->socksbuf+4+alen); + if (atype == 1) { + /* REP=0 (success) already */ + sk_write(pf->s, (char *) reply, lenof(reply)); + pf->hostname = dupprintf("%d.%d.%d.%d", + (unsigned char)pf->socksbuf[4], + (unsigned char)pf->socksbuf[5], + (unsigned char)pf->socksbuf[6], + (unsigned char)pf->socksbuf[7]); + goto connect; + } else if (atype == 3) { + /* REP=0 (success) already */ + sk_write(pf->s, (char *) reply, lenof(reply)); + pf->hostname = snewn(alen, char); + pf->hostname[alen-1] = '\0'; + memcpy(pf->hostname, pf->socksbuf + 5, alen-1); + goto connect; + } else { + /* + * Unknown address type. (FIXME: support IPv6!) + */ + reply[1] = 8; /* atype not supported */ + sk_write(pf->s, (char *) reply, lenof(reply)); + pfd_close(pf); + 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(pf); + return 1; + } + return 1; + + /* + * We come here when we're ready to make an actual + * connection. + */ + connect: + sfree(pf->socksbuf); + pf->socksbuf = NULL; + + /* + * Freeze the socket until the SSH server confirms the + * connection. + */ + sk_set_frozen(pf->s, 1); + + pf->c = new_sock_channel(pf->backhandle, pf); + if (pf->c == NULL) { + pfd_close(pf); + return 1; + } else { + /* asks to forward to the specified host/port for this */ + ssh_send_port_open(pf->c, pf->hostname, pf->port, "forwarding"); + } + pf->dynamic = 0; + + /* + * If there's any data remaining in our current buffer, + * save it to be sent on pfd_confirm(). + */ + if (len > 0) { + pf->buffer = snewn(len, char); + memcpy(pf->buffer, data, len); + pf->buflen = len; + } + } + if (pf->ready) { + if (sshfwd_write(pf->c, data, len) > 0) { + pf->throttled = 1; + sk_set_frozen(pf->s, 1); + } + } + return 1; +} + +static void pfd_sent(Plug plug, int bufsize) +{ + struct PortForwarding *pf = (struct PortForwarding *) plug; + + if (pf->c) + sshfwd_unthrottle(pf->c, bufsize); +} + +/* + * Called when receiving a PORT OPEN from the server to make a + * connection to a destination host. + * + * On success, returns NULL and fills in *pf_ret. On error, returns a + * dynamically allocated error message string. + */ +char *pfd_connect(struct PortForwarding **pf_ret, char *hostname,int port, + void *c, Conf *conf, 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 PortForwarding *pf; + + /* + * Try to find host. + */ + addr = name_lookup(hostname, port, &dummy_realhost, conf, addressfamily); + if ((err = sk_addr_error(addr)) != NULL) { + char *err_ret = dupstr(err); + sk_addr_free(addr); + sfree(dummy_realhost); + return err_ret; + } + + /* + * Open socket. + */ + pf = *pf_ret = new_portfwd_state(); + pf->fn = &fn_table; + pf->throttled = pf->throttle_override = 0; + pf->ready = 1; + pf->c = c; + pf->backhandle = NULL; /* we shouldn't need this */ + pf->dynamic = 0; + + pf->s = new_connection(addr, dummy_realhost, port, + 0, 1, 0, 0, (Plug) pf, conf); + sfree(dummy_realhost); + if ((err = sk_socket_error(pf->s)) != NULL) { + char *err_ret = dupstr(err); + sk_close(pf->s); + free_portfwd_state(pf); + *pf_ret = NULL; + return err_ret; + } + + return NULL; +} + +/* + called when someone connects to the local port + */ + +static int pfl_accepting(Plug p, accept_fn_t constructor, accept_ctx_t ctx) +{ + static const struct plug_function_table fn_table = { + pfd_log, + pfd_closing, + pfd_receive, + pfd_sent, + NULL + }; + struct PortForwarding *pf; + struct PortListener *pl; + Socket s; + const char *err; + + pl = (struct PortListener *)p; + pf = new_portfwd_state(); + pf->fn = &fn_table; + + pf->c = NULL; + pf->backhandle = pl->backhandle; + + pf->s = s = constructor(ctx, (Plug) pf); + if ((err = sk_socket_error(s)) != NULL) { + free_portfwd_state(pf); + return err != NULL; + } + + pf->throttled = pf->throttle_override = 0; + pf->ready = 0; + + if (pl->dynamic) { + pf->dynamic = 1; + pf->port = 0; /* "hostname" buffer is so far empty */ + sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */ + } else { + pf->dynamic = 0; + pf->hostname = dupstr(pl->hostname); + pf->port = pl->port; + pf->c = new_sock_channel(pl->backhandle, pf); + + if (pf->c == NULL) { + free_portfwd_state(pf); + return 1; + } else { + /* asks to forward to the specified host/port for this */ + ssh_send_port_open(pf->c, pf->hostname, pf->port, "forwarding"); + } + } + + return 0; +} + + +/* + * Add a new port-forwarding listener from srcaddr:port -> desthost:destport. + * + * On success, returns NULL and fills in *pl_ret. On error, returns a + * dynamically allocated error message string. + */ +char *pfl_listen(char *desthost, int destport, char *srcaddr, + int port, void *backhandle, Conf *conf, + struct PortListener **pl_ret, int address_family) +{ + static const struct plug_function_table fn_table = { + pfl_log, + pfl_closing, + NULL, /* recv */ + NULL, /* send */ + pfl_accepting + }; + + const char *err; + struct PortListener *pl; + + /* + * Open socket. + */ + pl = *pl_ret = new_portlistener_state(); + pl->fn = &fn_table; + if (desthost) { + pl->hostname = dupstr(desthost); + pl->port = destport; + pl->dynamic = 0; + } else + pl->dynamic = 1; + pl->backhandle = backhandle; + + pl->s = new_listener(srcaddr, port, (Plug) pl, + !conf_get_int(conf, CONF_lport_acceptall), + conf, address_family); + if ((err = sk_socket_error(pl->s)) != NULL) { + char *err_ret = dupstr(err); + sk_close(pl->s); + free_portlistener_state(pl); + *pl_ret = NULL; + return err_ret; + } + + return NULL; +} + +void pfd_close(struct PortForwarding *pf) +{ + if (!pf) + return; + + sk_close(pf->s); + free_portfwd_state(pf); +} + +/* + * Terminate a listener. + */ +void pfl_terminate(struct PortListener *pl) +{ + if (!pl) + return; + + sk_close(pl->s); + free_portlistener_state(pl); +} + +void pfd_unthrottle(struct PortForwarding *pf) +{ + if (!pf) + return; + + pf->throttled = 0; + sk_set_frozen(pf->s, pf->throttled || pf->throttle_override); +} + +void pfd_override_throttle(struct PortForwarding *pf, int enable) +{ + if (!pf) + return; + + pf->throttle_override = enable; + sk_set_frozen(pf->s, pf->throttled || pf->throttle_override); +} + +/* + * Called to send data down the raw connection. + */ +int pfd_send(struct PortForwarding *pf, char *data, int len) +{ + if (pf == NULL) + return 0; + return sk_write(pf->s, data, len); +} + +void pfd_send_eof(struct PortForwarding *pf) +{ + sk_write_eof(pf->s); +} + +void pfd_confirm(struct PortForwarding *pf) +{ + if (pf == NULL) + return; + + pf->ready = 1; + sk_set_frozen(pf->s, 0); + sk_write(pf->s, NULL, 0); + if (pf->buffer) { + sshfwd_write(pf->c, pf->buffer, pf->buflen); + sfree(pf->buffer); + pf->buffer = NULL; + } +} |