upstream: allow %n to be expanded in ProxyCommand strings

From Zachary Harmany via github.com/openssh/openssh-portable/pull/118
ok dtucker@

OpenBSD-Commit-ID: 7eebf1b7695f50c66d42053d352a4db9e8fb84b6

4 files changed, 28 insertions, 22 deletions

diff --git a/ssh.c b/ssh.c
index cb321bcf..ee51823c 100644
--- a/ssh.c
+++ b/ssh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.506 2019/09/06 14:45:34 naddy Exp $ */
+/* $OpenBSD: ssh.c,v 1.507 2019/09/13 04:27:35 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1369,7 +1369,7 @@ main(int ac, char **av)
 	timeout_ms = options.connection_timeout * 1000;
 
 	/* Open a connection to the remote host. */
-	if (ssh_connect(ssh, host, addrs, &hostaddr, options.port,
+	if (ssh_connect(ssh, host_arg, host, addrs, &hostaddr, options.port,
 	    options.address_family, options.connection_attempts,
 	    &timeout_ms, options.tcp_keep_alive) != 0)
  		exit(255);
diff --git a/ssh_config.5 b/ssh_config.5
index b10c5549..867c916a 100644
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -33,7 +33,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: ssh_config.5,v 1.302 2019/09/13 04:07:42 djm Exp $
+.\" $OpenBSD: ssh_config.5,v 1.303 2019/09/13 04:27:35 djm Exp $
 .Dd $Mdocdate: September 13 2019 $
 .Dt SSH_CONFIG 5
 .Os
@@ -1821,7 +1821,7 @@ accept the tokens %%, %d, %h, %i, %l, %r, and %u.
 accepts the tokens %%, %C, %d, %h, %i, %l, %n, %p, %r, %T, and %u.
 .Pp
 .Cm ProxyCommand
-accepts the tokens %%, %h, %p, and %r.
+accepts the tokens %%, %h, %n, %p, and %r.
 .Pp
 .Cm RemoteCommand
 accepts the tokens %%, %C, %d, %h, %i, %l, %n, %p, %r, and %u.
diff --git a/sshconnect.c b/sshconnect.c
index ed44fccb..74078044 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect.c,v 1.317 2019/06/28 13:35:04 deraadt Exp $ */
+/* $OpenBSD: sshconnect.c,v 1.318 2019/09/13 04:27:35 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -87,14 +87,18 @@ static void warn_changed_key(struct sshkey *);
 /* Expand a proxy command */
 static char *
 expand_proxy_command(const char *proxy_command, const char *user,
-    const char *host, int port)
+    const char *host, const char *host_arg, int port)
 {
 	char *tmp, *ret, strport[NI_MAXSERV];
 
 	snprintf(strport, sizeof strport, "%d", port);
 	xasprintf(&tmp, "exec %s", proxy_command);
-	ret = percent_expand(tmp, "h", host, "p", strport,
-	    "r", options.user, (char *)NULL);
+	ret = percent_expand(tmp,
+	    "h", host,
+	    "n", host_arg,
+	    "p", strport,
+	    "r", options.user,
+	    (char *)NULL);
 	free(tmp);
 	return ret;
 }
@@ -122,8 +126,8 @@ stderr_null(void)
  * a connected fd back to us.
  */
 static int
-ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host, u_short port,
-    const char *proxy_command)
+ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host,
+    const char *host_arg, u_short port, const char *proxy_command)
 {
 	char *command_string;
 	int sp[2], sock;
@@ -138,7 +142,7 @@ ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host, u_short port,
 		    "proxy dialer: %.100s", strerror(errno));
 
 	command_string = expand_proxy_command(proxy_command, options.user,
-	    host, port);
+	    host_arg, host, port);
 	debug("Executing proxy dialer command: %.500s", command_string);
 
 	/* Fork and execute the proxy command. */
@@ -204,8 +208,8 @@ ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host, u_short port,
  * Connect to the given ssh server using a proxy command.
  */
 static int
-ssh_proxy_connect(struct ssh *ssh, const char *host, u_short port,
-    const char *proxy_command)
+ssh_proxy_connect(struct ssh *ssh, const char *host, const char *host_arg,
+    u_short port, const char *proxy_command)
 {
 	char *command_string;
 	int pin[2], pout[2];
@@ -221,7 +225,7 @@ ssh_proxy_connect(struct ssh *ssh, const char *host, u_short port,
 		    strerror(errno));
 
 	command_string = expand_proxy_command(proxy_command, options.user,
-	    host, port);
+	    host_arg, host, port);
 	debug("Executing proxy command: %.500s", command_string);
 
 	/* Fork and execute the proxy command. */
@@ -543,9 +547,9 @@ ssh_connect_direct(struct ssh *ssh, const char *host, struct addrinfo *aitop,
 }
 
 int
-ssh_connect(struct ssh *ssh, const char *host, struct addrinfo *addrs,
-    struct sockaddr_storage *hostaddr, u_short port, int family,
-    int connection_attempts, int *timeout_ms, int want_keepalive)
+ssh_connect(struct ssh *ssh, const char *host, const char *host_arg,
+    struct addrinfo *addrs, struct sockaddr_storage *hostaddr, u_short port,
+    int family, int connection_attempts, int *timeout_ms, int want_keepalive)
 {
 	int in, out;
 
@@ -564,10 +568,11 @@ ssh_connect(struct ssh *ssh, const char *host, struct addrinfo *addrs,
 			return -1; /* ssh_packet_set_connection logs error */
 		return 0;
 	} else if (options.proxy_use_fdpass) {
-		return ssh_proxy_fdpass_connect(ssh, host, port,
+		return ssh_proxy_fdpass_connect(ssh, host, host_arg, port,
 		    options.proxy_command);
 	}
-	return ssh_proxy_connect(ssh, host, port, options.proxy_command);
+	return ssh_proxy_connect(ssh, host, host_arg, port,
+	    options.proxy_command);
 }
 
 /* defaults to 'no' */
diff --git a/sshconnect.h b/sshconnect.h
index b455d7c2..2e84b8bc 100644
--- a/sshconnect.h
+++ b/sshconnect.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect.h,v 1.38 2019/06/21 04:21:05 djm Exp $ */
+/* $OpenBSD: sshconnect.h,v 1.39 2019/09/13 04:27:35 djm Exp $ */
 
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
@@ -33,8 +33,9 @@ struct Sensitive {
 struct addrinfo;
 struct ssh;
 
-int	 ssh_connect(struct ssh *, const char *, struct addrinfo *,
-	    struct sockaddr_storage *, u_short, int, int, int *, int);
+int	 ssh_connect(struct ssh *, const char *, const char *,
+	    struct addrinfo *, struct sockaddr_storage *, u_short,
+	    int, int, int *, int);
 void	 ssh_kill_proxy_command(void);
 
 void	 ssh_login(struct ssh *, Sensitive *, const char *,