- djm@cvs.openbsd.org 2004/06/13 15:03:02

     [channels.c channels.h clientloop.c clientloop.h includes.h readconf.c]
     [readconf.h scp.1 sftp.1 ssh.1 ssh.c ssh_config.5]
     implement session multiplexing in the client (the server has supported
     this since 2.0); ok markus@

1 files changed, 184 insertions, 92 deletions

diff --git a/ssh.c b/ssh.c
index 3c21fa37d..1c6ec8b6a 100644
--- a/ssh.c
+++ b/ssh.c
@@ -40,7 +40,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh.c,v 1.213 2004/05/08 00:01:37 deraadt Exp $");
+RCSID("$OpenBSD: ssh.c,v 1.214 2004/06/13 15:03:02 djm Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -53,21 +53,24 @@ RCSID("$OpenBSD: ssh.c,v 1.213 2004/05/08 00:01:37 deraadt Exp $");
 #include "xmalloc.h"
 #include "packet.h"
 #include "buffer.h"
+#include "bufaux.h"
 #include "channels.h"
 #include "key.h"
 #include "authfd.h"
 #include "authfile.h"
 #include "pathnames.h"
+#include "dispatch.h"
 #include "clientloop.h"
 #include "log.h"
 #include "readconf.h"
 #include "sshconnect.h"
-#include "dispatch.h"
 #include "misc.h"
 #include "kex.h"
 #include "mac.h"
 #include "sshpty.h"
 #include "match.h"
+#include "msg.h"
+#include "monitor_fdpass.h"
 
 #ifdef SMARTCARD
 #include "scard.h"
@@ -141,6 +144,13 @@ static int client_global_request_id = 0;
 /* pid of proxycommand child process */
 pid_t proxy_command_pid = 0;
 
+/* fd to control socket */
+int control_fd = -1;
+
+/* Only used in control client mode */
+volatile sig_atomic_t control_client_terminate = 0;
+u_int control_server_pid = 0;
+
 /* Prints a help message to the user.  This function never returns. */
 
 static void
@@ -158,6 +168,7 @@ usage(void)
 static int ssh_session(void);
 static int ssh_session2(void);
 static void load_public_identity_files(void);
+static void control_client(const char *path);
 
 /*
  * Main program for the ssh client.
@@ -228,7 +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:NPR:TVXY")) != -1) {
+            "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNPR:S:TVXY")) != -1) {
                 switch (opt) {
                 case '1':
                         options.protocol = SSH_PROTO_1;
@@ -364,6 +375,9 @@ again:
                                 exit(1);
                         }
                         break;
+                case 'M':
+                        options.control_master = 1;
+                        break;
                 case 'p':
                         options.port = a2port(optarg);
                         if (options.port == 0) {
@@ -432,6 +446,13 @@ again:
                 case 's':
                         subsystem_flag = 1;
                         break;
+                case 'S':
+                        if (options.control_path != NULL)
+                                free(options.control_path);
+                        options.control_path = xstrdup(optarg);
+                        if (options.control_master == -1)
+                                options.control_master = 0;
+                        break;
                 case 'b':
                         options.bind_address = optarg;
                         break;
@@ -566,6 +587,13 @@ again:
             strcmp(options.proxy_command, "none") == 0)
                 options.proxy_command = NULL;
 
+        if (options.control_path != NULL) {
+                options.control_path = tilde_expand_filename(
+                   options.control_path, original_real_uid);
+        }
+        if (options.control_path != NULL && options.control_master == 0)
+                control_client(options.control_path); /* This doesn't return */
+
         /* Open a connection to the remote host. */
         if (ssh_connect(host, &hostaddr, options.port,
             options.address_family, options.connection_attempts,
@@ -678,6 +706,9 @@ again:
         exit_status = compat20 ? ssh_session2() : ssh_session();
         packet_close();
 
+        if (options.control_path != NULL && control_fd != -1)
+                unlink(options.control_path);
+
         /*
          * Send SIGHUP to proxy command if used. We don't wait() in
          * case it hangs and instead rely on init to reap the child
@@ -974,7 +1005,7 @@ ssh_session(void)
 }
 
 static void
-client_subsystem_reply(int type, u_int32_t seq, void *ctxt)
+ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt)
 {
         int id, len;
 
@@ -1006,40 +1037,50 @@ client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
                     options.remote_forwards[i].port);
 }
 
-/* request pty/x11/agent/tcpfwd/shell for channel */
 static void
-ssh_session2_setup(int id, void *arg)
+ssh_control_listener(void)
 {
-        int len;
-        int interactive = 0;
-        struct termios tio;
+        struct sockaddr_un addr;
+        mode_t old_umask;
+        
+        if (options.control_path == NULL || options.control_master != 1)
+                return;
 
-        debug2("ssh_session2_setup: id %d", id);
+        memset(&addr, '\0', sizeof(addr));
+        addr.sun_family = AF_UNIX;
+        addr.sun_len = offsetof(struct sockaddr_un, sun_path) +
+            strlen(options.control_path) + 1;
 
-        if (tty_flag) {
-                struct winsize ws;
-                char *cp;
-                cp = getenv("TERM");
-                if (!cp)
-                        cp = "";
-                /* Store window size in the packet. */
-                if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
-                        memset(&ws, 0, sizeof(ws));
+        if (strlcpy(addr.sun_path, options.control_path,
+            sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
+                fatal("ControlPath too long");
 
-                channel_request_start(id, "pty-req", 0);
-                packet_put_cstring(cp);
-                packet_put_int(ws.ws_col);
-                packet_put_int(ws.ws_row);
-                packet_put_int(ws.ws_xpixel);
-                packet_put_int(ws.ws_ypixel);
-                tio = get_saved_tio();
-                tty_make_modes(/*ignored*/ 0, &tio);
-                packet_send();
-                interactive = 1;
-                /* XXX wait for reply */
+        if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
+                fatal("%s socket(): %s\n", __func__, strerror(errno));
+
+        old_umask = umask(0177);
+        if (bind(control_fd, (struct sockaddr*)&addr, addr.sun_len) == -1) {
+                control_fd = -1;
+                if (errno == EINVAL)
+                        fatal("ControlSocket %s already exists",
+                            options.control_path);
+                else
+                        fatal("%s bind(): %s\n", __func__, strerror(errno));
         }
-        if (options.forward_x11 &&
-            getenv("DISPLAY") != NULL) {
+        umask(old_umask);
+
+        if (listen(control_fd, 64) == -1)
+                fatal("%s listen(): %s\n", __func__, strerror(errno));
+
+        set_nonblock(control_fd);
+}
+
+/* request pty/x11/agent/tcpfwd/shell for channel */
+static void
+ssh_session2_setup(int id, void *arg)
+{
+        int interactive = tty_flag;
+        if (options.forward_x11 && getenv("DISPLAY") != NULL) {
                 char *proto, *data;
                 /* Get reasonable local authentication information. */
                 x11_get_proto(&proto, &data);
@@ -1057,65 +1098,8 @@ ssh_session2_setup(int id, void *arg)
                 packet_send();
         }
 
-        /* Transfer any environment variables from client to server */
-        if (options.num_send_env != 0) {
-                int i, j, matched;
-                extern char **environ;
-                char *name, *val;
-
-                debug("Sending environment.");
-                for (i = 0; environ && environ[i] != NULL; i++) {
-                        /* Split */
-                        name = xstrdup(environ[i]);
-                        if ((val = strchr(name, '=')) == NULL) {
-                                free(name);
-                                continue;
-                        }
-                        *val++ = '\0';
-
-                        matched = 0;
-                        for (j = 0; j < options.num_send_env; j++) {
-                                if (match_pattern(name, options.send_env[j])) {
-                                        matched = 1;
-                                        break;
-                                }
-                        }
-                        if (!matched) {
-                                debug3("Ignored env %s", name);
-                                free(name);
-                                continue;
-                        }
-
-                        debug("Sending env %s = %s", name, val);
-                        channel_request_start(id, "env", 0);
-                        packet_put_cstring(name);
-                        packet_put_cstring(val);
-                        packet_send();
-                        free(name);
-                }
-        }
-
-        len = buffer_len(&command);
-        if (len > 0) {
-                if (len > 900)
-                        len = 900;
-                if (subsystem_flag) {
-                        debug("Sending subsystem: %.*s", len, (u_char *)buffer_ptr(&command));
-                        channel_request_start(id, "subsystem", /*want reply*/ 1);
-                        /* register callback for reply */
-                        /* XXX we assume that client_loop has already been called */
-                        dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply);
-                        dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply);
-                } else {
-                        debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
-                        channel_request_start(id, "exec", 0);
-                }
-                packet_put_string(buffer_ptr(&command), buffer_len(&command));
-                packet_send();
-        } else {
-                channel_request_start(id, "shell", 0);
-                packet_send();
-        }
+        client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
+            NULL, fileno(stdin), &command, &ssh_subsystem_reply);
 
         packet_set_interactive(interactive);
 }
@@ -1161,7 +1145,7 @@ ssh_session2_open(void)
 
         channel_send_open(c->self);
         if (!no_shell_flag)
-                channel_register_confirm(c->self, ssh_session2_setup);
+                channel_register_confirm(c->self, ssh_session2_setup, NULL);
 
         return c->self;
 }
@@ -1173,6 +1157,7 @@ ssh_session2(void)
 
         /* XXX should be pre-session */
         ssh_init_forwarding();
+        ssh_control_listener();
 
         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
                 id = ssh_session2_open();
@@ -1226,3 +1211,110 @@ load_public_identity_files(void)
                 options.identity_keys[i] = public;
         }
 }
+
+static void
+control_client_sighandler(int signo)
+{
+        control_client_terminate = signo;
+}
+
+static void
+control_client_sigrelay(int signo)
+{
+        if (control_server_pid > 1)
+                kill(control_server_pid, signo);
+}
+
+static void
+control_client(const char *path)
+{
+        struct sockaddr_un addr;
+        int r, sock, exitval;
+        Buffer m;
+        char *cp;
+        
+        memset(&addr, '\0', sizeof(addr));
+        addr.sun_family = AF_UNIX;
+        addr.sun_len = offsetof(struct sockaddr_un, sun_path) +
+            strlen(path) + 1;
+
+        if (strlcpy(addr.sun_path, path,
+            sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
+                fatal("ControlPath too long");
+
+        if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
+                fatal("%s socket(): %s", __func__, strerror(errno));
+
+        if (connect(sock, (struct sockaddr*)&addr, addr.sun_len) == -1)
+                fatal("Couldn't connect to %s: %s", path, strerror(errno));
+
+        if ((cp = getenv("TERM")) == NULL)
+                cp = "";
+
+        signal(SIGINT, control_client_sighandler);
+        signal(SIGTERM, control_client_sighandler);
+        signal(SIGWINCH, control_client_sigrelay);
+
+        buffer_init(&m);
+
+        /* Get PID of controlee */
+        if (ssh_msg_recv(sock, &m) == -1)
+                fatal("%s: msg_recv", __func__);
+        if (buffer_get_char(&m) != 0)
+                fatal("%s: wrong version", __func__);
+        control_server_pid = buffer_get_int(&m);
+
+        /* XXX: env passing */
+
+        buffer_clear(&m);
+        buffer_put_int(&m, tty_flag);
+        buffer_put_int(&m, subsystem_flag);
+        buffer_put_cstring(&m, cp);
+
+        buffer_append(&command, "\0", 1);
+        buffer_put_cstring(&m, buffer_ptr(&command));
+
+        if (ssh_msg_send(sock, /* version */0, &m) == -1)
+                fatal("%s: msg_send", __func__);
+
+        mm_send_fd(sock, STDIN_FILENO);
+        mm_send_fd(sock, STDOUT_FILENO);
+        mm_send_fd(sock, STDERR_FILENO);
+
+        /* Wait for reply, so master has a chance to gather ttymodes */
+        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__);
+        buffer_free(&m);
+
+        if (tty_flag)
+                enter_raw_mode();
+
+        /* Stick around until the controlee closes the client_fd */
+        exitval = 0;
+        for (;!control_client_terminate;) {
+                r = read(sock, &exitval, sizeof(exitval));
+                if (r == 0) {
+                        debug2("Received EOF from master");
+                        break;
+                }
+                if (r > 0)
+                        debug2("Received exit status from master %d", exitval);
+                if (r == -1 && errno != EINTR)
+                        fatal("%s: read %s", __func__, strerror(errno));
+        }
+
+        if (control_client_terminate)
+                debug2("Exiting on signal %d", control_client_terminate);
+
+        close(sock);
+
+        leave_raw_mode();
+
+        if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
+                fprintf(stderr, "Connection to master closed.\r\n");
+
+        exit(exitval);
+}