Attachment 3355 Details for Bug 3116 – abort connection for tunnel forward failures when ExitOnForwardFailure is set

[patch] abort connection for tunnel forward failures when ExitOnForwardFailure is set

bz3116.diff (text/plain), 4.65 KB, created by Damien Miller on 2020-01-31 16:20:26 AEDT

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Creator: Damien Miller

Created: 2020-01-31 16:20:26 AEDT

Size: 4.65 KB

patch

obsolete

>diff --git a/clientloop.c b/clientloop.c
>index f7ce3a2..f35ccfb 100644
>--- a/clientloop.c
>+++ b/clientloop.c
>@@ -1641,7 +1641,7 @@ client_request_agent(struct ssh *ssh, const char *request_type, int rchan)
> 
> char *
> client_request_tun_fwd(struct ssh *ssh, int tun_mode,
>-    int local_tun, int remote_tun)
>+    int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx)
> {
> 	Channel *c;
> 	int r, fd;
>@@ -1663,6 +1663,9 @@ client_request_tun_fwd(struct ssh *ssh, int tun_mode,
> 	    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
> 	c->datagram = 1;
> 
>+	if (cb != NULL)
>+		channel_register_open_confirm(ssh, c->self, cb, cbctx);
>+
> 	if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
> 	    (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 ||
> 	    (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
>diff --git a/clientloop.h b/clientloop.h
>index bf79c87..4604e7c 100644
>--- a/clientloop.h
>+++ b/clientloop.h
>@@ -46,7 +46,8 @@ int	 client_x11_get_proto(struct ssh *, const char *, const char *,
> void	 client_global_request_reply_fwd(int, u_int32_t, void *);
> void	 client_session2_setup(struct ssh *, int, int, int,
> 	    const char *, struct termios *, int, struct sshbuf *, char **);
>-char	 *client_request_tun_fwd(struct ssh *, int, int, int);
>+char	 *client_request_tun_fwd(struct ssh *, int, int, int,
>+    channel_open_fn *, void *);
> void	 client_stop_mux(void);
> 
> /* Escape filter for protocol 2 sessions */
>diff --git a/ssh.c b/ssh.c
>index 314b3c5..37a693c 100644
>--- a/ssh.c
>+++ b/ssh.c
>@@ -175,7 +175,7 @@ struct sshbuf *command;
> int subsystem_flag = 0;
> 
> /* # of replies received for global requests */
>-static int remote_forward_confirms_received = 0;
>+static int forward_confirms_pending = -1;
> 
> /* mux.c */
> extern int muxserver_sock;
>@@ -1640,6 +1640,16 @@ fork_postauth(void)
> 		fatal("daemon() failed: %.200s", strerror(errno));
> }
> 
>+static void
>+forwarding_success(void)
>+{
>+	if (forward_confirms_pending > 0 && --forward_confirms_pending == 0) {
>+		debug("All forwarding requests processed");
>+		if (fork_after_authentication_flag)
>+			fork_postauth();
>+	}
>+}
>+
> /* Callback for remote forward global requests */
> static void
> ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
>@@ -1699,11 +1709,7 @@ ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
> 				    "for listen port %d", rfwd->listen_port);
> 		}
> 	}
>-	if (++remote_forward_confirms_received == options.num_remote_forwards) {
>-		debug("All remote forwarding requests processed");
>-		if (fork_after_authentication_flag)
>-			fork_postauth();
>-	}
>+	forwarding_success();
> }
> 
> static void
>@@ -1720,6 +1726,19 @@ ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
> 		fatal("stdio forwarding failed");
> }
> 
>+static void
>+ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
>+{
>+	if (!success) {
>+		error("Tunnel forwarding failed");
>+		if (options.exit_on_forward_failure)
>+			cleanup_exit(255);
>+	}
>+
>+	debug("%s: tunnel forward established, id=%d", __func__, id);
>+	forwarding_success();
>+}
>+
> static void
> ssh_init_stdio_forwarding(struct ssh *ssh)
> {
>@@ -1783,32 +1802,29 @@ ssh_init_forwarding(struct ssh *ssh, char **ifname)
> 		    options.remote_forwards[i].connect_path :
> 		    options.remote_forwards[i].connect_host,
> 		    options.remote_forwards[i].connect_port);
>-		options.remote_forwards[i].handle =
>+		if ((options.remote_forwards[i].handle =
> 		    channel_request_remote_forwarding(ssh,
>-		    &options.remote_forwards[i]);
>-		if (options.remote_forwards[i].handle < 0) {
>-			if (options.exit_on_forward_failure)
>-				fatal("Could not request remote forwarding.");
>-			else
>-				logit("Warning: Could not request remote "
>-				    "forwarding.");
>-		} else {
>+		    &options.remote_forwards[i])) >= 0) {
> 			client_register_global_confirm(
> 			    ssh_confirm_remote_forward,
> 			    &options.remote_forwards[i]);
>-		}
>+			forward_confirms_pending++;
>+		} else if (options.exit_on_forward_failure)
>+			fatal("Could not request remote forwarding.");
>+		else
>+			logit("Warning: Could not request remote forwarding.");
> 	}
> 
> 	/* Initiate tunnel forwarding. */
> 	if (options.tun_open != SSH_TUNMODE_NO) {
> 		if ((*ifname = client_request_tun_fwd(ssh,
> 		    options.tun_open, options.tun_local,
>-		    options.tun_remote)) == NULL) {
>-			if (options.exit_on_forward_failure)
>-				fatal("Could not request tunnel forwarding.");
>-			else
>-				error("Could not request tunnel forwarding.");
>-		}
>+		    options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
>+			forward_confirms_pending++;
>+		else if (options.exit_on_forward_failure)
>+			fatal("Could not request tunnel forwarding.");
>+		else
>+			error("Could not request tunnel forwarding.");
> 	}
> }
>

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Attachments on bug 3116: 3355