Integrate unfix.org's IPv6 patches up to level 10, with rather a lot
[u/mdw/putty] / ssh.c
diff --git a/ssh.c b/ssh.c
index dc58727..170253b 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -497,11 +497,35 @@ struct ssh_channel {
  * Hence, in SSH 1 this structure is indexed by destination
  * host:port pair, whereas in SSH 2 it is indexed by source port.
  */
+struct ssh_portfwd; /* forward declaration */
+
 struct ssh_rportfwd {
     unsigned sport, dport;
     char dhost[256];
     char *sportdesc;
+    struct ssh_portfwd *pfrec;
+};
+#define free_rportfwd(pf) ( \
+    ((pf) ? (sfree((pf)->sportdesc)) : (void)0 ), sfree(pf) )
+
+/*
+ * Separately to the rportfwd tree (which is for looking up port
+ * open requests from the server), a tree of _these_ structures is
+ * used to keep track of all the currently open port forwardings,
+ * so that we can reconfigure in mid-session if the user requests
+ * it.
+ */
+struct ssh_portfwd {
+    int keep;
+    int type;
+    unsigned sport, dport;
+    char *saddr, *daddr;
+    struct ssh_rportfwd *remote;
+    int addressfamily;
+    void *local;
 };
+#define free_portfwd(pf) ( \
+    ((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr)) : (void)0 ), sfree(pf) )
 
 struct Packet {
     long length;
@@ -616,7 +640,7 @@ struct ssh_tag {
     struct ssh_channel *mainchan;      /* primary session channel */
     int exitcode;
 
-    tree234 *rportfwds;
+    tree234 *rportfwds, *portfwds;
 
     enum {
        SSH_STATE_PREPACKET,
@@ -723,7 +747,7 @@ struct ssh_tag {
     unsigned long incoming_data_size, outgoing_data_size, deferred_data_size;
     unsigned long max_data_size;
     int kex_in_progress;
-    long next_rekey;
+    long next_rekey, last_rekey;
 };
 
 #define logevent(s) logevent(ssh->frontend, s)
@@ -816,6 +840,47 @@ static int ssh_rportcmp_ssh2(void *av, void *bv)
     return 0;
 }
 
+/*
+ * Special form of strcmp which can cope with NULL inputs. NULL is
+ * defined to sort before even the empty string.
+ */
+static int nullstrcmp(const char *a, const char *b)
+{
+    if (a == NULL && b == NULL)
+       return 0;
+    if (a == NULL)
+       return -1;
+    if (b == NULL)
+       return +1;
+    return strcmp(a, b);
+}
+
+static int ssh_portcmp(void *av, void *bv)
+{
+    struct ssh_portfwd *a = (struct ssh_portfwd *) av;
+    struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
+    int i;
+    if (a->type > b->type)
+       return +1;
+    if (a->type < b->type)
+       return -1;
+    if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
+       return i < 0 ? -1 : +1;
+    if (a->sport > b->sport)
+       return +1;
+    if (a->sport < b->sport)
+       return -1;
+    if (a->type != 'D') {
+       if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
+           return i < 0 ? -1 : +1;
+       if (a->dport > b->dport)
+           return +1;
+       if (a->dport < b->dport)
+           return -1;
+    }
+    return 0;
+}
+
 static int alloc_channel_id(Ssh ssh)
 {
     const unsigned CHANNEL_NUMBER_OFFSET = 256;
@@ -2385,8 +2450,11 @@ static const char *connect_to_host(Ssh ssh, char *host, int port,
     /*
      * Try to find host.
      */
-    logeventf(ssh, "Looking up host \"%s\"", host);
-    addr = name_lookup(host, port, realhost, &ssh->cfg);
+    logeventf(ssh, "Looking up host \"%s\"%s", host,
+             (ssh->cfg.addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
+              (ssh->cfg.addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" : "")));
+    addr = name_lookup(host, port, realhost, &ssh->cfg,
+                      ssh->cfg.addressfamily);
     if ((err = sk_addr_error(addr)) != NULL) {
        sk_addr_free(addr);
        return err;
@@ -3596,14 +3664,13 @@ static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
 
        rpf = del234(ssh->rportfwds, pf);
        assert(rpf == pf);
-       sfree(pf->sportdesc);
-       sfree(pf);
+       free_rportfwd(pf);
     }
 }
 
 static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
 {
-    char type;
+    char address_family, type;
     int n;
     int sport,dport,sserv,dserv;
     char sports[256], dports[256], saddr[256], host[256];
@@ -3611,9 +3678,38 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
 
     portfwd_strptr = cfg->portfwd;
 
+    if (!ssh->portfwds) {
+       ssh->portfwds = newtree234(ssh_portcmp);
+    } else {
+       /*
+        * Go through the existing port forwardings and tag them
+        * with keep==FALSE. Any that we want to keep will be
+        * re-enabled as we go through the configuration and find
+        * out which bits are the same as they were before.
+        */
+       struct ssh_portfwd *epf;
+       int i;
+       for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
+           epf->keep = FALSE;
+    }
+
     while (*portfwd_strptr) {
-       type = *portfwd_strptr++;
+       address_family = 'A';
+       type = 'L';
+       while (*portfwd_strptr && *portfwd_strptr != '\t') {
+           if (*portfwd_strptr == 'A' ||
+               *portfwd_strptr == '4' ||
+               *portfwd_strptr == '6')
+               address_family = *portfwd_strptr;
+           else if (*portfwd_strptr == 'L' ||
+               *portfwd_strptr == 'R' ||
+               *portfwd_strptr == 'D')
+               type = *portfwd_strptr;
+           portfwd_strptr++;
+       }
+
        saddr[0] = '\0';
+
        n = 0;
        while (*portfwd_strptr && *portfwd_strptr != '\t') {
            if (*portfwd_strptr == ':') {
@@ -3680,13 +3776,36 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
        }
        if (sport && dport) {
            /* Set up a description of the source port. */
-           static char *sportdesc;
+           struct ssh_portfwd *pfrec, *epfrec;
+           char *sportdesc;
            sportdesc = dupprintf("%.*s%.*s%.*s%.*s%d%.*s",
                                  (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
                                  (int)(*saddr?1:0), ":",
                                  (int)(sserv ? strlen(sports) : 0), sports,
                                  sserv, "(", sport, sserv, ")");
-           if (type == 'L') {
+
+           pfrec = snew(struct ssh_portfwd);
+           pfrec->type = type;
+           pfrec->saddr = *saddr ? dupstr(saddr) : NULL;
+           pfrec->sport = sport;
+           pfrec->daddr = dupstr(host);
+           pfrec->dport = dport;
+           pfrec->local = NULL;
+           pfrec->remote = NULL;
+           pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
+                                   address_family == '6' ? ADDRTYPE_IPV6 :
+                                   ADDRTYPE_UNSPEC);
+
+           epfrec = add234(ssh->portfwds, pfrec);
+           if (epfrec != pfrec) {
+               /*
+                * We already have a port forwarding with precisely
+                * these parameters. Hence, no need to do anything;
+                * simply tag the existing one as `keep'.
+                */
+               epfrec->keep = TRUE;
+               free_portfwd(pfrec);
+           } else if (type == 'L') {
                /* Verbose description of the destination port */
                char *dportdesc = dupprintf("%s:%.*s%.*s%d%.*s",
                                            host,
@@ -3694,26 +3813,29 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
                                            dserv, "(", dport, dserv, ")");
                const char *err = pfd_addforward(host, dport,
                                                 *saddr ? saddr : NULL,
-                                                sport, ssh, &ssh->cfg);
-               if (err) {
-                   logeventf(ssh, "Local port %s forward to %s"
-                             " failed: %s", sportdesc, dportdesc, err);
-               } else {
-                   logeventf(ssh, "Local port %s forwarding to %s",
-                             sportdesc, dportdesc);
-               }
+                                                sport, ssh, &ssh->cfg,
+                                                &pfrec->local,
+                                                pfrec->addressfamily);
+
+               logeventf(ssh, "Local %sport %s forward to %s%s%s",
+                         pfrec->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
+                         pfrec->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
+                         sportdesc, dportdesc,
+                         err ? " failed: " : "", err);
+
                sfree(dportdesc);
            } else if (type == 'D') {
                const char *err = pfd_addforward(NULL, -1,
                                                 *saddr ? saddr : NULL,
-                                                sport, ssh, &ssh->cfg);
-               if (err) {
-                   logeventf(ssh, "Local port %s SOCKS dynamic forward"
-                             " setup failed: %s", sportdesc, err);
-               } else {
-                   logeventf(ssh, "Local port %s doing SOCKS"
-                             " dynamic forwarding", sportdesc);
-               }
+                                                sport, ssh, &ssh->cfg,
+                                                &pfrec->local,
+                                                pfrec->addressfamily);
+
+                       logeventf(ssh, "Local %sport %s SOCKS dynamic forward%s%s",
+                                 pfrec->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
+                                 pfrec->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
+                                 sportdesc,
+                                 err ? " setup failed: " : "", err);
            } else {
                struct ssh_rportfwd *pf;
 
@@ -3744,6 +3866,8 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
 
                    pf->sportdesc = sportdesc;
                    sportdesc = NULL;
+                   pfrec->remote = pf;
+                   pf->pfrec = pfrec;
 
                    if (ssh->version == 1) {
                        send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
@@ -3778,6 +3902,78 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
            sfree(sportdesc);
        }
     }
+
+    /*
+     * Now go through and destroy any port forwardings which were
+     * not re-enabled.
+     */
+    {
+       struct ssh_portfwd *epf;
+       int i;
+       for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
+           if (!epf->keep) {
+               char *message;
+
+               message = dupprintf("%s port forwarding from %s%s%d",
+                                   epf->type == 'L' ? "local" :
+                                   epf->type == 'R' ? "remote" : "dynamic",
+                                   epf->saddr ? epf->saddr : "",
+                                   epf->saddr ? ":" : "",
+                                   epf->sport);
+
+               if (epf->type != 'D') {
+                   char *msg2 = dupprintf("%s to %s:%d", message,
+                                          epf->daddr, epf->dport);
+                   sfree(message);
+                   message = msg2;
+               }
+
+               logeventf(ssh, "Cancelling %s", message);
+               sfree(message);
+
+               if (epf->remote) {
+                   struct ssh_rportfwd *rpf = epf->remote;
+                   struct Packet *pktout;
+
+                   /*
+                    * Cancel the port forwarding at the server
+                    * end.
+                    */
+                   if (ssh->version == 1) {
+                       /*
+                        * We cannot cancel listening ports on the
+                        * server side in SSH1! There's no message
+                        * to support it. Instead, we simply remove
+                        * the rportfwd record from the local end
+                        * so that any connections the server tries
+                        * to make on it are rejected.
+                        */
+                   } else {
+                       pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
+                       ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
+                       ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
+                       if (epf->saddr) {
+                           ssh2_pkt_addstring(pktout, epf->saddr);
+                       } else if (ssh->cfg.rport_acceptall) {
+                           ssh2_pkt_addstring(pktout, "0.0.0.0");
+                       } else {
+                           ssh2_pkt_addstring(pktout, "127.0.0.1");
+                       }
+                       ssh2_pkt_adduint32(pktout, epf->sport);
+                       ssh2_pkt_send(ssh, pktout);
+                   }
+
+                   del234(ssh->rportfwds, rpf);
+                   free_rportfwd(rpf);
+               } else if (epf->local) {
+                   pfd_terminate(epf->local);
+               }
+
+               delpos234(ssh->portfwds, i);
+               free_portfwd(epf);
+               i--;                   /* so we don't skip one in the list */
+           }
+    }
 }
 
 static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
@@ -3871,7 +4067,7 @@ static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
     /* Remote side is trying to open a channel to talk to a
      * forwarded port. Give them back a local channel number. */
     struct ssh_channel *c;
-    struct ssh_rportfwd pf;
+    struct ssh_rportfwd pf, *pfp;
     int remoteid;
     int hostsize, port;
     char *host, buf[1024];
@@ -3888,8 +4084,9 @@ static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
     memcpy(pf.dhost, host, hostsize);
     pf.dhost[hostsize] = '\0';
     pf.dport = port;
+    pfp = find234(ssh->rportfwds, &pf, NULL);
 
-    if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
+    if (pfp == NULL) {
        sprintf(buf, "Rejected remote port open request for %s:%d",
                pf.dhost, port);
        logevent(buf);
@@ -3900,7 +4097,7 @@ static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
                pf.dhost, port);
        logevent(buf);
        e = pfd_newconnect(&c->u.pfd.s, pf.dhost, port,
-                          c, &ssh->cfg);
+                          c, &ssh->cfg, pfp->pfrec->addressfamily);
        if (e != NULL) {
            char buf[256];
            sprintf(buf, "Port open failed: %s", e);
@@ -4011,7 +4208,7 @@ static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
     /* Data sent down one of our channels. */
     int i = ssh_pkt_getuint32(pktin);
     char *p;
-    int len;
+    unsigned int len;
     struct ssh_channel *c;
 
     ssh_pkt_getstring(pktin, &p, &len);
@@ -4030,7 +4227,7 @@ static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
            /* 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);
+                   unsigned int l = min(4 - c->u.a.lensofar, len);
                    memcpy(c->u.a.msglen + c->u.a.lensofar, p,
                           l);
                    p += l;
@@ -4045,7 +4242,7 @@ static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
                    memcpy(c->u.a.message, c->u.a.msglen, 4);
                }
                if (c->u.a.lensofar >= 4 && len > 0) {
-                   int l =
+                   unsigned int l =
                        min(c->u.a.totallen - c->u.a.lensofar,
                            len);
                    memcpy(c->u.a.message + c->u.a.lensofar, p,
@@ -5037,6 +5234,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen,
      * Key exchange is over. Schedule a timer for our next rekey.
      */
     ssh->kex_in_progress = FALSE;
+    ssh->last_rekey = GETTICKCOUNT();
     if (ssh->cfg.ssh_rekey_time != 0)
        ssh->next_rekey = schedule_timer(ssh->cfg.ssh_rekey_time*60*TICKSPERSEC,
                                         ssh2_timer, ssh);
@@ -5160,7 +5358,7 @@ static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
 static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
 {
     char *data;
-    int length;
+    unsigned int length;
     unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
     c = find234(ssh->channels, &i, ssh_channelfind);
@@ -5189,7 +5387,7 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
          case CHAN_AGENT:
            while (length > 0) {
                if (c->u.a.lensofar < 4) {
-                   int l = min(4 - c->u.a.lensofar, length);
+                   unsigned int l = min(4 - c->u.a.lensofar, length);
                    memcpy(c->u.a.msglen + c->u.a.lensofar,
                           data, l);
                    data += l;
@@ -5204,7 +5402,7 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
                    memcpy(c->u.a.message, c->u.a.msglen, 4);
                }
                if (c->u.a.lensofar >= 4 && length > 0) {
-                   int l =
+                   unsigned int l =
                        min(c->u.a.totallen - c->u.a.lensofar,
                            length);
                    memcpy(c->u.a.message + c->u.a.lensofar,
@@ -5624,7 +5822,8 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
            const char *e = pfd_newconnect(&c->u.pfd.s,
                                           realpf->dhost,
                                           realpf->dport, c,
-                                          &ssh->cfg);
+                                          &ssh->cfg,
+                                          realpf->pfrec->addressfamily);
            logeventf(ssh, "Attempting to forward remote port to "
                      "%s:%d", realpf->dhost, realpf->dport);
            if (e != NULL) {
@@ -7039,7 +7238,7 @@ static void ssh2_timer(void *ctx, long now)
 {
     Ssh ssh = (Ssh)ctx;
 
-    if (!ssh->kex_in_progress &&
+    if (!ssh->kex_in_progress && ssh->cfg.ssh_rekey_time != 0 &&
        now - ssh->next_rekey >= 0) {
        do_ssh2_transport(ssh, "Initiating key re-exchange (timeout)",
                          -1, NULL);
@@ -7163,6 +7362,7 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
 
     ssh->channels = NULL;
     ssh->rportfwds = NULL;
+    ssh->portfwds = NULL;
 
     ssh->send_ok = 0;
     ssh->editing = 0;
@@ -7281,17 +7481,41 @@ static void ssh_free(void *handle)
 
 /*
  * Reconfigure the SSH backend.
- * 
- * Currently, this function does nothing very useful. In future,
- * however, we could do some handy things with it. For example, we
- * could make the port forwarding configurer active in the Change
- * Settings box, and this routine could close down existing
- * forwardings and open up new ones in response to changes.
  */
 static void ssh_reconfig(void *handle, Config *cfg)
 {
     Ssh ssh = (Ssh) handle;
+    char *rekeying = NULL;
+    unsigned long old_max_data_size;
+
     pinger_reconfig(ssh->pinger, &ssh->cfg, cfg);
+    ssh_setup_portfwd(ssh, cfg);
+
+    if (ssh->cfg.ssh_rekey_time != cfg->ssh_rekey_time &&
+       cfg->ssh_rekey_time != 0) {
+       long new_next = ssh->last_rekey + cfg->ssh_rekey_time*60*TICKSPERSEC;
+       long now = GETTICKCOUNT();
+
+       if (new_next - now < 0) {
+           rekeying = "Initiating key re-exchange (timeout shortened)";
+       } else {
+           ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh);
+       }
+    }
+
+    old_max_data_size = ssh->max_data_size;
+    ssh->max_data_size = parse_blocksize(cfg->ssh_rekey_data);
+    if (old_max_data_size != ssh->max_data_size &&
+       ssh->max_data_size != 0) {
+       if (ssh->outgoing_data_size > ssh->max_data_size ||
+           ssh->incoming_data_size > ssh->max_data_size)
+           rekeying = "Initiating key re-exchange (data limit lowered)";
+    }
+
+    if (rekeying && !ssh->kex_in_progress) {
+       do_ssh2_transport(ssh, rekeying, -1, NULL);
+    }
+
     ssh->cfg = *cfg;                  /* STRUCTURE COPY */
 }
 
@@ -7594,7 +7818,7 @@ void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
                    PKT_INT, c->localid,
                    PKT_STR, hostname,
                    PKT_INT, port,
-                   //PKT_STR, <org:orgport>,
+                   /* PKT_STR, <org:orgport>, */
                    PKT_END);
     } else {
        pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
@@ -7661,6 +7885,16 @@ static int ssh_return_exitcode(void *handle)
 }
 
 /*
+ * cfg_info for SSH is the currently running version of the
+ * protocol. (1 for 1; 2 for 2; 0 for not-decided-yet.)
+ */
+static int ssh_cfg_info(void *handle)
+{
+    Ssh ssh = (Ssh) handle;
+    return ssh->version;
+}
+
+/*
  * Gross hack: pscp will try to start SFTP but fall back to scp1 if
  * that fails. This variable is the means by which scp.c can reach
  * into the SSH code and find out which one it got.
@@ -7687,5 +7921,6 @@ Backend ssh_backend = {
     ssh_provide_ldisc,
     ssh_provide_logctx,
     ssh_unthrottle,
+    ssh_cfg_info,
     22
 };