5 files changed, 149 insertions, 88 deletions

diff --git a/ChangeLog b/ChangeLog
index bd6b640b1..9e683143a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -104,6 +104,13 @@
      client stderr (subject to LogLevel in the mux master) - better than
      silently failing.
      most bits ok markus@ (as part of a larger diff)
+   - djm@cvs.openbsd.org 2008/05/09 04:55:56
+     [channels.c channels.h clientloop.c serverloop.c]
+     Try additional addresses when connecting to a port forward destination
+     whose DNS name resolves to more than one address. The previous behaviour
+     was to try the first address and give up.
+     Reported by stig AT venaas.com in bz#343
+     great feedback and ok markus@
 
 20080403
  - (djm) [openbsd-compat/bsd-poll.c] Include stdlib.h to avoid compile-
@@ -3964,4 +3971,4 @@
    OpenServer 6 and add osr5bigcrypt support so when someone migrates
    passwords between UnixWare and OpenServer they will still work. OK dtucker@
 
-$Id: ChangeLog,v 1.4924 2008/05/19 05:36:08 djm Exp $
+$Id: ChangeLog,v 1.4925 2008/05/19 05:37:09 djm Exp $
diff --git a/channels.c b/channels.c
index b5e28dabf..1e57951dc 100644
--- a/channels.c
+++ b/channels.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.275 2008/05/08 12:02:23 djm Exp $ */
+/* $OpenBSD: channels.c,v 1.276 2008/05/09 04:55:56 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -165,6 +165,10 @@ static int IPv4or6 = AF_UNSPEC;
 /* helper */
 static void port_open_helper(Channel *c, char *rtype);
 
+/* non-blocking connect helpers */
+static int connect_next(struct channel_connect *);
+static void channel_connect_ctx_free(struct channel_connect *);
+
 /* -- channel core */
 
 Channel *
@@ -1425,7 +1429,7 @@ channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
 static void
 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
 {
-        int err = 0;
+        int err = 0, sock;
         socklen_t sz = sizeof(err);
 
         if (FD_ISSET(c->sock, writeset)) {
@@ -1434,7 +1438,9 @@ channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
                         error("getsockopt SO_ERROR failed");
                 }
                 if (err == 0) {
-                        debug("channel %d: connected", c->self);
+                        debug("channel %d: connected to %s port %d",
+                            c->self, c->connect_ctx.host, c->connect_ctx.port);
+                        channel_connect_ctx_free(&c->connect_ctx);
                         c->type = SSH_CHANNEL_OPEN;
                         if (compat20) {
                                 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
@@ -1448,8 +1454,19 @@ channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
                                 packet_put_int(c->self);
                         }
                 } else {
-                        debug("channel %d: not connected: %s",
+                        debug("channel %d: connection failed: %s",
                             c->self, strerror(err));
+                        /* Try next address, if any */
+                        if ((sock = connect_next(&c->connect_ctx)) > 0) {
+                                close(c->sock);
+                                c->sock = c->rfd = c->wfd = sock;
+                                channel_max_fd = channel_find_maxfd();
+                                return;
+                        }
+                        /* Exhausted all addresses */
+                        error("connect_to %.100s port %d: failed.",
+                            c->connect_ctx.host, c->connect_ctx.port);
+                        channel_connect_ctx_free(&c->connect_ctx);
                         if (compat20) {
                                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
                                 packet_put_int(c->remote_id);
@@ -2327,7 +2344,7 @@ channel_input_port_open(int type, u_int32_t seq, void *ctxt)
         Channel *c = NULL;
         u_short host_port;
         char *host, *originator_string;
-        int remote_id, sock = -1;
+        int remote_id;
 
         remote_id = packet_get_int();
         host = packet_get_string(NULL);
@@ -2339,20 +2356,16 @@ channel_input_port_open(int type, u_int32_t seq, void *ctxt)
                 originator_string = xstrdup("unknown (remote did not supply name)");
         }
         packet_check_eom();
-        sock = channel_connect_to(host, host_port);
-        if (sock != -1) {
-                c = channel_new("connected socket",
-                    SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
-                    originator_string, 1);
-                c->remote_id = remote_id;
-        }
+        c = channel_connect_to(host, host_port,
+            "connected socket", originator_string);
         xfree(originator_string);
+        xfree(host);
         if (c == NULL) {
                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
                 packet_put_int(remote_id);
                 packet_send();
-        }
-        xfree(host);
+        } else
+                c->remote_id = remote_id;
 }
 
 /* ARGSUSED */
@@ -2770,35 +2783,26 @@ channel_clear_adm_permitted_opens(void)
         num_adm_permitted_opens = 0;
 }
 
-/* return socket to remote host, port */
+/* Try to start non-blocking connect to next host in cctx list */
 static int
-connect_to(const char *host, u_short port)
+connect_next(struct channel_connect *cctx)
 {
-        struct addrinfo hints, *ai, *aitop;
+        int sock, saved_errno;
         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
-        int gaierr;
-        int sock = -1;
 
-        memset(&hints, 0, sizeof(hints));
-        hints.ai_family = IPv4or6;
-        hints.ai_socktype = SOCK_STREAM;
-        snprintf(strport, sizeof strport, "%d", port);
-        if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
-                error("connect_to %.100s: unknown host (%s)", host,
-                    ssh_gai_strerror(gaierr));
-                return -1;
-        }
-        for (ai = aitop; ai; ai = ai->ai_next) {
-                if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
+        for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
+                if (cctx->ai->ai_family != AF_INET &&
+                    cctx->ai->ai_family != AF_INET6)
                         continue;
-                if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
-                    strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
-                        error("connect_to: getnameinfo failed");
+                if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
+                    ntop, sizeof(ntop), strport, sizeof(strport),
+                    NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
+                        error("connect_next: getnameinfo failed");
                         continue;
                 }
-                sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
-                if (sock < 0) {
-                        if (ai->ai_next == NULL)
+                if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
+                    cctx->ai->ai_protocol)) == -1) {
+                        if (cctx->ai->ai_next == NULL)
                                 error("socket: %.100s", strerror(errno));
                         else
                                 verbose("socket: %.100s", strerror(errno));
@@ -2806,45 +2810,94 @@ connect_to(const char *host, u_short port)
                 }
                 if (set_nonblock(sock) == -1)
                         fatal("%s: set_nonblock(%d)", __func__, sock);
-                if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
-                    errno != EINPROGRESS) {
-                        error("connect_to %.100s port %s: %.100s", ntop, strport,
+                if (connect(sock, cctx->ai->ai_addr,
+                    cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
+                        debug("connect_next: host %.100s ([%.100s]:%s): "
+                            "%.100s", cctx->host, ntop, strport,
                             strerror(errno));
+                        saved_errno = errno;
                         close(sock);
+                        errno = saved_errno;
                         continue;       /* fail -- try next */
                 }
-                break; /* success */
+                debug("connect_next: host %.100s ([%.100s]:%s) "
+                    "in progress, fd=%d", cctx->host, ntop, strport, sock);
+                cctx->ai = cctx->ai->ai_next;
+                set_nodelay(sock);
+                return sock;
+        }
+        return -1;
+}
+
+static void
+channel_connect_ctx_free(struct channel_connect *cctx)
+{
+        xfree(cctx->host);
+        if (cctx->aitop)
+                freeaddrinfo(cctx->aitop);
+        bzero(cctx, sizeof(*cctx));
+        cctx->host = NULL;
+        cctx->ai = cctx->aitop = NULL;
+}
 
+/* Return CONNECTING channel to remote host, port */
+static Channel *
+connect_to(const char *host, u_short port, char *ctype, char *rname)
+{
+        struct addrinfo hints;
+        int gaierr;
+        int sock = -1;
+        char strport[NI_MAXSERV];
+        struct channel_connect cctx;
+        Channel *c;
+
+        memset(&hints, 0, sizeof(hints));
+        hints.ai_family = IPv4or6;
+        hints.ai_socktype = SOCK_STREAM;
+        snprintf(strport, sizeof strport, "%d", port);
+        if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
+                error("connect_to %.100s: unknown host (%s)", host,
+                    ssh_gai_strerror(gaierr));
+                return NULL;
         }
-        freeaddrinfo(aitop);
-        if (!ai) {
-                error("connect_to %.100s port %d: failed.", host, port);
-                return -1;
+
+        cctx.host = xstrdup(host);
+        cctx.port = port;
+        cctx.ai = cctx.aitop;
+
+        if ((sock = connect_next(&cctx)) == -1) {
+                error("connect to %.100s port %d failed: %s",
+                    host, port, strerror(errno));
+                channel_connect_ctx_free(&cctx);
+                return NULL;
         }
-        /* success */
-        set_nodelay(sock);
-        return sock;
+        c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
+            CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
+        c->connect_ctx = cctx;
+        return c;
 }
 
-int
-channel_connect_by_listen_address(u_short listen_port)
+Channel *
+channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
 {
         int i;
 
-        for (i = 0; i < num_permitted_opens; i++)
+        for (i = 0; i < num_permitted_opens; i++) {
                 if (permitted_opens[i].host_to_connect != NULL &&
-                    permitted_opens[i].listen_port == listen_port)
+                    permitted_opens[i].listen_port == listen_port) {
                         return connect_to(
                             permitted_opens[i].host_to_connect,
-                            permitted_opens[i].port_to_connect);
+                            permitted_opens[i].port_to_connect, ctype, rname);
+                }
+        }
         error("WARNING: Server requests forwarding for unknown listen_port %d",
             listen_port);
-        return -1;
+        return NULL;
 }
 
 /* Check if connecting to that port is permitted and connect. */
-int
-channel_connect_to(const char *host, u_short port)
+Channel *
+channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
 {
         int i, permit, permit_adm = 1;
 
@@ -2870,9 +2923,9 @@ channel_connect_to(const char *host, u_short port)
         if (!permit || !permit_adm) {
                 logit("Received request to connect to host %.100s port %d, "
                     "but the request was denied.", host, port);
-                return -1;
+                return NULL;
         }
-        return connect_to(host, port);
+        return connect_to(host, port, ctype, rname);
 }
 
 void
diff --git a/channels.h b/channels.h
index 46cde0309..d4ac24a51 100644
--- a/channels.h
+++ b/channels.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.h,v 1.90 2008/05/08 12:02:23 djm Exp $ */
+/* $OpenBSD: channels.h,v 1.91 2008/05/09 04:55:56 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -75,6 +75,13 @@ struct channel_confirm {
 };
 TAILQ_HEAD(channel_confirms, channel_confirm);
 
+/* Context for non-blocking connects */
+struct channel_connect {
+        char *host;
+        int port;
+        struct addrinfo *ai, *aitop;
+};
+
 struct Channel {
         int     type;           /* channel type/state */
         int     self;           /* my own channel identifier */
@@ -125,7 +132,11 @@ struct Channel {
         channel_infilter_fn     *input_filter;
         channel_outfilter_fn    *output_filter;
 
-        int     datagram;       /* keep boundaries */
+        /* keep boundaries */
+        int                     datagram;
+
+        /* non-blocking connect */
+        struct channel_connect  connect_ctx;
 };
 
 #define CHAN_EXTENDED_IGNORE            0
@@ -225,8 +236,8 @@ int	 channel_add_adm_permitted_opens(char *, int);
 void     channel_clear_permitted_opens(void);
 void     channel_clear_adm_permitted_opens(void);
 int      channel_input_port_forward_request(int, int);
-int      channel_connect_to(const char *, u_short);
-int      channel_connect_by_listen_address(u_short);
+Channel *channel_connect_to(const char *, u_short, char *, char *);
+Channel *channel_connect_by_listen_address(u_short, char *, char *);
 int      channel_request_remote_forwarding(const char *, u_short,
              const char *, u_short);
 int      channel_setup_local_fwd_listener(const char *, u_short,
@@ -241,7 +252,7 @@ int	 x11_connect_display(void);
 int      x11_create_display_inet(int, int, int, u_int *, int **);
 void     x11_input_open(int, u_int32_t, void *);
 void     x11_request_forwarding_with_spoofing(int, const char *, const char *,
-            const char *);
+             const char *);
 void     deny_input_open(int, u_int32_t, void *);
 
 /* agent forwarding */
diff --git a/clientloop.c b/clientloop.c
index c40f2c303..7bd1af60c 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: clientloop.c,v 1.190 2008/05/08 13:06:10 djm Exp $ */
+/* $OpenBSD: clientloop.c,v 1.191 2008/05/09 04:55:56 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1762,7 +1762,6 @@ client_request_forwarded_tcpip(const char *request_type, int rchan)
         Channel *c = NULL;
         char *listen_address, *originator_address;
         int listen_port, originator_port;
-        int sock;
 
         /* Get rest of the packet */
         listen_address = packet_get_string(NULL);
@@ -1771,19 +1770,13 @@ client_request_forwarded_tcpip(const char *request_type, int rchan)
         originator_port = packet_get_int();
         packet_check_eom();
 
-        debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
-            listen_address, listen_port, originator_address, originator_port);
+        debug("client_request_forwarded_tcpip: listen %s port %d, "
+            "originator %s port %d", listen_address, listen_port,
+            originator_address, originator_port);
+
+        c = channel_connect_by_listen_address(listen_port,
+            "forwarded-tcpip", originator_address);
 
-        sock = channel_connect_by_listen_address(listen_port);
-        if (sock < 0) {
-                xfree(originator_address);
-                xfree(listen_address);
-                return NULL;
-        }
-        c = channel_new("forwarded-tcpip",
-            SSH_CHANNEL_CONNECTING, sock, sock, -1,
-            CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
-            originator_address, 1);
         xfree(originator_address);
         xfree(listen_address);
         return c;
diff --git a/serverloop.c b/serverloop.c
index 20991c3ce..2142f3809 100644
--- a/serverloop.c
+++ b/serverloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: serverloop.c,v 1.149 2008/05/08 12:02:23 djm Exp $ */
+/* $OpenBSD: serverloop.c,v 1.150 2008/05/09 04:55:56 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -938,7 +938,6 @@ static Channel *
 server_request_direct_tcpip(void)
 {
         Channel *c;
-        int sock;
         char *target, *originator;
         int target_port, originator_port;
 
@@ -948,18 +947,16 @@ server_request_direct_tcpip(void)
         originator_port = packet_get_int();
         packet_check_eom();
 
-        debug("server_request_direct_tcpip: originator %s port %d, target %s port %d",
-            originator, originator_port, target, target_port);
+        debug("server_request_direct_tcpip: originator %s port %d, target %s "
+            "port %d", originator, originator_port, target, target_port);
 
         /* XXX check permission */
-        sock = channel_connect_to(target, target_port);
-        xfree(target);
+        c = channel_connect_to(target, target_port,
+            "direct-tcpip", "direct-tcpip");
+
         xfree(originator);
-        if (sock < 0)
-                return NULL;
-        c = channel_new("direct-tcpip", SSH_CHANNEL_CONNECTING,
-            sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
-            CHAN_TCP_PACKET_DEFAULT, 0, "direct-tcpip", 1);
+        xfree(target);
+
         return c;
 }