- djm@cvs.openbsd.org 2004/11/07 00:01:46

     [clientloop.c clientloop.h ssh.1 ssh.c]
     add basic control of a running multiplex master connection; including the
     ability to check its status and request it to exit; ok markus@

5 files changed, 153 insertions, 34 deletions

diff --git a/ChangeLog b/ChangeLog
index 871187478..fe96f8d0c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,6 +4,10 @@
      [sftp.c]
      command editing and history support via libedit; ok markus@
      thanks to hshoexer@ and many testers on tech@ too
+   - djm@cvs.openbsd.org 2004/11/07 00:01:46
+     [clientloop.c clientloop.h ssh.1 ssh.c]
+     add basic control of a running multiplex master connection; including the
+     ability to check its status and request it to exit; ok markus@
 
 20041105
  - (dtucker) OpenBSD CVS Sync
@@ -1848,4 +1852,4 @@
    - (djm) Trim deprecated options from INSTALL. Mention UsePAM
    - (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
 
-$Id: ChangeLog,v 1.3579 2004/11/07 09:04:10 dtucker Exp $
+$Id: ChangeLog,v 1.3580 2004/11/07 09:06:19 dtucker Exp $
diff --git a/clientloop.c b/clientloop.c
index d77337b82..033a98a5b 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -59,7 +59,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: clientloop.c,v 1.133 2004/10/29 22:53:56 djm Exp $");
+RCSID("$OpenBSD: clientloop.c,v 1.134 2004/11/07 00:01:46 djm Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -561,7 +561,7 @@ client_process_control(fd_set * readset)
         struct sockaddr_storage addr;
         struct confirm_ctx *cctx;
         char *cmd;
-        u_int len, env_len;
+        u_int len, env_len, command, flags;
         uid_t euid;
         gid_t egid;
 
@@ -591,24 +591,74 @@ client_process_control(fd_set * readset)
                 return;
         }
 
-        allowed = 1;
-        if (options.control_master == 2)
-                allowed = ask_permission("Allow shared connection to %s? ",
-                    host);
-
         unset_nonblock(client_fd);
 
+        /* Read command */
         buffer_init(&m);
+        if (ssh_msg_recv(client_fd, &m) == -1) {
+                error("%s: client msg_recv failed", __func__);
+                close(client_fd);
+                buffer_free(&m);
+                return;
+        }
+        if ((ver = buffer_get_char(&m)) != 1) {
+                error("%s: wrong client version %d", __func__, ver);
+                buffer_free(&m);
+                close(client_fd);
+                return;
+        }
+
+        allowed = 1;
+        command = buffer_get_int(&m);
+        flags = buffer_get_int(&m);
+
+        buffer_clear(&m);
 
+        switch (command) {
+        case SSHMUX_COMMAND_OPEN:
+                if (options.control_master == 2)
+                        allowed = ask_permission("Allow shared connection "
+                            "to %s? ", host);
+                /* continue below */
+                break;
+        case SSHMUX_COMMAND_TERMINATE:
+                if (options.control_master == 2)
+                        allowed = ask_permission("Terminate shared connection "
+                            "to %s? ", host);
+                if (allowed)
+                        quit_pending = 1;
+                /* FALLTHROUGH */       
+        case SSHMUX_COMMAND_ALIVE_CHECK:
+                /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */
+                buffer_clear(&m);
+                buffer_put_int(&m, allowed);
+                buffer_put_int(&m, getpid());
+                if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
+                        error("%s: client msg_send failed", __func__);
+                        close(client_fd);
+                        buffer_free(&m);
+                        return;
+                }
+                buffer_free(&m);
+                close(client_fd);
+                return;
+        default:
+                error("Unsupported command %d", command);
+                buffer_free(&m);
+                close(client_fd);
+                return;
+        }
+
+        /* Reply for SSHMUX_COMMAND_OPEN */
+        buffer_clear(&m);
         buffer_put_int(&m, allowed);
         buffer_put_int(&m, getpid());
-        if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
+        if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
                 error("%s: client msg_send failed", __func__);
                 close(client_fd);
                 buffer_free(&m);
                 return;
         }
-        buffer_clear(&m);
 
         if (!allowed) {
                 error("Refused control connection");
@@ -617,14 +667,14 @@ client_process_control(fd_set * readset)
                 return;
         }
 
+        buffer_clear(&m);
         if (ssh_msg_recv(client_fd, &m) == -1) {
                 error("%s: client msg_recv failed", __func__);
                 close(client_fd);
                 buffer_free(&m);
                 return;
         }
-
-        if ((ver = buffer_get_char(&m)) != 0) {
+        if ((ver = buffer_get_char(&m)) != 1) {
                 error("%s: wrong client version %d", __func__, ver);
                 buffer_free(&m);
                 close(client_fd);
@@ -633,9 +683,8 @@ client_process_control(fd_set * readset)
 
         cctx = xmalloc(sizeof(*cctx));
         memset(cctx, 0, sizeof(*cctx));
-
-        cctx->want_tty = buffer_get_int(&m);
-        cctx->want_subsys = buffer_get_int(&m);
+        cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0;
+        cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0;
         cctx->term = buffer_get_string(&m, &len);
 
         cmd = buffer_get_string(&m, &len);
@@ -667,14 +716,21 @@ client_process_control(fd_set * readset)
         if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
                 error("%s: tcgetattr: %s", __func__, strerror(errno));
 
+        /* This roundtrip is just for synchronisation of ttymodes */
         buffer_clear(&m);
-        if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
+        if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
                 error("%s: client msg_send failed", __func__);
                 close(client_fd);
                 close(new_fd[0]);
                 close(new_fd[1]);
                 close(new_fd[2]);
                 buffer_free(&m);
+                xfree(cctx->term);
+                if (env_len != 0) {
+                        for (i = 0; i < env_len; i++)
+                                xfree(cctx->env[i]);
+                        xfree(cctx->env);
+                }
                 return;
         }
         buffer_free(&m);
diff --git a/clientloop.h b/clientloop.h
index 9992d5938..b23c111cb 100644
--- a/clientloop.h
+++ b/clientloop.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: clientloop.h,v 1.11 2004/07/11 17:48:47 deraadt Exp $ */
+/*      $OpenBSD: clientloop.h,v 1.12 2004/11/07 00:01:46 djm Exp $     */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -40,3 +40,11 @@ int	 client_loop(int, int, int);
 void     client_global_request_reply_fwd(int, u_int32_t, void *);
 void     client_session2_setup(int, int, int, const char *, struct termios *,
             int, Buffer *, char **, dispatch_fn *);
+
+/* Multiplexing control protocol flags */
+#define SSHMUX_COMMAND_OPEN             1       /* Open new connection */
+#define SSHMUX_COMMAND_ALIVE_CHECK      2       /* Check master is alive */
+#define SSHMUX_COMMAND_TERMINATE        3       /* Ask master to exit */
+
+#define SSHMUX_FLAG_TTY                 (1)     /* Request tty on open */
+#define SSHMUX_FLAG_SUBSYS              (1<<1)  /* Subsystem request on open */
diff --git a/ssh.1 b/ssh.1
index 06cb60cec..ec83319b8 100644
--- a/ssh.1
+++ b/ssh.1
@@ -34,7 +34,7 @@
 .\" (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.1,v 1.197 2004/10/07 10:10:24 djm Exp $
+.\" $OpenBSD: ssh.1,v 1.198 2004/11/07 00:01:46 djm Exp $
 .Dd September 25, 1999
 .Dt SSH 1
 .Os
@@ -62,6 +62,7 @@
 .Ek
 .Op Fl l Ar login_name
 .Op Fl m Ar mac_spec
+.Op Fl O Ar ctl_cmd
 .Op Fl o Ar option
 .Bk -words
 .Op Fl p Ar port
@@ -74,7 +75,7 @@
 .Sm on
 .Xc
 .Oc
-.Op Fl S Ar ctl
+.Op Fl S Ar ctl_path
 .Oo Ar user Ns @ Oc Ns Ar hostname
 .Op Ar command
 .Sh DESCRIPTION
@@ -613,6 +614,18 @@ be specified in order of preference.
 See the
 .Cm MACs
 keyword for more information.
+.It Fl O Ar ctl_cmd
+Control an active connection multiplexing master process.
+When the
+.Fl O
+option is specified, the 
+.Ar ctl_cmd
+argument is interpreted and passed to the master process.
+Valid commands are:
+.Dq check
+(check that the master process is running) and 
+.Dq exit
+(request the master to exit).
 .It Fl N
 Do not execute a remote command.
 This is useful for just forwarding ports
@@ -735,7 +748,7 @@ IPv6 addresses can be specified with an alternative syntax:
 .Ar hostport .
 .Xc
 .Sm on
-.It Fl S Ar ctl
+.It Fl S Ar ctl_path
 Specifies the location of a control socket for connection sharing.
 Refer to the description of
 .Cm ControlPath
diff --git a/ssh.c b/ssh.c
index c231c5fae..dfe9b25c1 100644
--- a/ssh.c
+++ b/ssh.c
@@ -40,7 +40,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh.c,v 1.228 2004/09/23 13:00:04 djm Exp $");
+RCSID("$OpenBSD: ssh.c,v 1.229 2004/11/07 00:01:46 djm Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -144,6 +144,9 @@ pid_t proxy_command_pid = 0;
 /* fd to control socket */
 int control_fd = -1;
 
+/* Multiplexing control command */
+static u_int mux_command = SSHMUX_COMMAND_OPEN;
+
 /* Only used in control client mode */
 volatile sig_atomic_t control_client_terminate = 0;
 u_int control_server_pid = 0;
@@ -236,7 +239,7 @@ main(int ac, char **av)
 
 again:
         while ((opt = getopt(ac, av,
-            "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNPR:S:TVXY")) != -1) {
+            "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNO:PR:S:TVXY")) != -1) {
                 switch (opt) {
                 case '1':
                         options.protocol = SSH_PROTO_1;
@@ -270,6 +273,14 @@ again:
                 case 'g':
                         options.gateway_ports = 1;
                         break;
+                case 'O':
+                        if (strcmp(optarg, "check") == 0)
+                                mux_command = SSHMUX_COMMAND_ALIVE_CHECK;
+                        else if (strcmp(optarg, "exit") == 0)
+                                mux_command = SSHMUX_COMMAND_TERMINATE;
+                        else
+                                fatal("Invalid multiplex command.");
+                        break;
                 case 'P':       /* deprecated */
                         options.use_privileged_port = 0;
                         break;
@@ -1251,8 +1262,9 @@ control_client(const char *path)
         struct sockaddr_un addr;
         int i, r, fd, sock, exitval, num_env, addr_len;
         Buffer m;
-        char *cp;
+        char *term;
         extern char **environ;
+        u_int  flags;
 
         if (stdin_null_flag) {
                 if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1)
@@ -1278,26 +1290,52 @@ control_client(const char *path)
         if (connect(sock, (struct sockaddr*)&addr, addr_len) == -1)
                 fatal("Couldn't connect to %s: %s", path, strerror(errno));
 
-        if ((cp = getenv("TERM")) == NULL)
-                cp = "";
+        if ((term = getenv("TERM")) == NULL)
+                term = "";
+
+        flags = 0;
+        if (tty_flag)
+                flags |= SSHMUX_FLAG_TTY;
+        if (subsystem_flag)
+                flags |= SSHMUX_FLAG_SUBSYS;
 
         buffer_init(&m);
 
-        /* Get PID of controlee */
+        /* Send our command to server */
+        buffer_put_int(&m, mux_command);
+        buffer_put_int(&m, flags);
+        if (ssh_msg_send(sock, /* version */1, &m) == -1)
+                fatal("%s: msg_send", __func__);
+        buffer_clear(&m);
+
+        /* Get authorisation status and PID of controlee */
         if (ssh_msg_recv(sock, &m) == -1)
                 fatal("%s: msg_recv", __func__);
-        if (buffer_get_char(&m) != 0)
+        if (buffer_get_char(&m) != 1)
                 fatal("%s: wrong version", __func__);
-        /* Connection allowed? */
         if (buffer_get_int(&m) != 1)
                 fatal("Connection to master denied");
         control_server_pid = buffer_get_int(&m);
 
         buffer_clear(&m);
-        buffer_put_int(&m, tty_flag);
-        buffer_put_int(&m, subsystem_flag);
-        buffer_put_cstring(&m, cp);
 
+        switch (mux_command) {
+        case SSHMUX_COMMAND_ALIVE_CHECK:
+                fprintf(stderr, "Master running (pid=%d)\r\n", 
+                    control_server_pid);
+                exit(0);
+        case SSHMUX_COMMAND_TERMINATE:
+                fprintf(stderr, "Exit request sent.\r\n");
+                exit(0);
+        case SSHMUX_COMMAND_OPEN:
+                /* continue below */
+                break;
+        default:
+                fatal("silly mux_command %d", mux_command);
+        }
+
+        /* SSHMUX_COMMAND_OPEN */
+        buffer_put_cstring(&m, term);
         buffer_append(&command, "\0", 1);
         buffer_put_cstring(&m, buffer_ptr(&command));
 
@@ -1319,7 +1357,7 @@ control_client(const char *path)
                         }
         }
 
-        if (ssh_msg_send(sock, /* version */0, &m) == -1)
+        if (ssh_msg_send(sock, /* version */1, &m) == -1)
                 fatal("%s: msg_send", __func__);
 
         mm_send_fd(sock, STDIN_FILENO);
@@ -1330,8 +1368,8 @@ control_client(const char *path)
         buffer_clear(&m);
         if (ssh_msg_recv(sock, &m) == -1)
                 fatal("%s: msg_recv", __func__);
-        if (buffer_get_char(&m) != 0)
-                fatal("%s: master returned error", __func__);
+        if (buffer_get_char(&m) != 1)
+                fatal("%s: wrong version", __func__);
         buffer_free(&m);
 
         signal(SIGHUP, control_client_sighandler);