]> andersk Git - openssh.git/blobdiff - clientloop.c
- djm@cvs.openbsd.org 2006/03/19 07:41:30
[openssh.git] / clientloop.c
index 1e250883f1821a0366982953ce2d7eca9b795513..6d58a5afbc8ac25ce9e2076ec7499bb7ba302377 100644 (file)
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: clientloop.c,v 1.135 2005/03/01 10:09:52 djm Exp $");
+
+#include <sys/types.h>
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+#include <sys/ioctl.h>
+
+#include <ctype.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#include <signal.h>
+#include <termios.h>
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -77,6 +89,7 @@ RCSID("$OpenBSD: clientloop.c,v 1.135 2005/03/01 10:09:52 djm Exp $");
 #include "log.h"
 #include "readconf.h"
 #include "clientloop.h"
+#include "sshconnect.h"
 #include "authfd.h"
 #include "atomicio.h"
 #include "sshpty.h"
@@ -113,7 +126,7 @@ extern char *host;
 static volatile sig_atomic_t received_window_change_signal = 0;
 static volatile sig_atomic_t received_signal = 0;
 
-/* Flag indicating whether the user\'s terminal is in non-blocking mode. */
+/* Flag indicating whether the user's terminal is in non-blocking mode. */
 static int in_non_blocking_mode = 0;
 
 /* Common data for the client loop code. */
@@ -140,6 +153,8 @@ int session_ident = -1;
 struct confirm_ctx {
        int want_tty;
        int want_subsys;
+       int want_x_fwd;
+       int want_agent_fwd;
        Buffer cmd;
        char *term;
        struct termios tio;
@@ -208,6 +223,109 @@ get_current_time(void)
        return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
 }
 
+#define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
+void
+client_x11_get_proto(const char *display, const char *xauth_path,
+    u_int trusted, char **_proto, char **_data)
+{
+       char cmd[1024];
+       char line[512];
+       char xdisplay[512];
+       static char proto[512], data[512];
+       FILE *f;
+       int got_data = 0, generated = 0, do_unlink = 0, i;
+       char *xauthdir, *xauthfile;
+       struct stat st;
+
+       xauthdir = xauthfile = NULL;
+       *_proto = proto;
+       *_data = data;
+       proto[0] = data[0] = '\0';
+
+       if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) {
+               debug("No xauth program.");
+       } else {
+               if (display == NULL) {
+                       debug("x11_get_proto: DISPLAY not set");
+                       return;
+               }
+               /*
+                * Handle FamilyLocal case where $DISPLAY does
+                * not match an authorization entry.  For this we
+                * just try "xauth list unix:displaynum.screennum".
+                * XXX: "localhost" match to determine FamilyLocal
+                *      is not perfect.
+                */
+               if (strncmp(display, "localhost:", 10) == 0) {
+                       snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
+                           display + 10);
+                       display = xdisplay;
+               }
+               if (trusted == 0) {
+                       xauthdir = xmalloc(MAXPATHLEN);
+                       xauthfile = xmalloc(MAXPATHLEN);
+                       strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
+                       if (mkdtemp(xauthdir) != NULL) {
+                               do_unlink = 1;
+                               snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile",
+                                   xauthdir);
+                               snprintf(cmd, sizeof(cmd),
+                                   "%s -f %s generate %s " SSH_X11_PROTO
+                                   " untrusted timeout 1200 2>" _PATH_DEVNULL,
+                                   xauth_path, xauthfile, display);
+                               debug2("x11_get_proto: %s", cmd);
+                               if (system(cmd) == 0)
+                                       generated = 1;
+                       }
+               }
+               snprintf(cmd, sizeof(cmd),
+                   "%s %s%s list %s 2>" _PATH_DEVNULL,
+                   xauth_path,
+                   generated ? "-f " : "" ,
+                   generated ? xauthfile : "",
+                   display);
+               debug2("x11_get_proto: %s", cmd);
+               f = popen(cmd, "r");
+               if (f && fgets(line, sizeof(line), f) &&
+                   sscanf(line, "%*s %511s %511s", proto, data) == 2)
+                       got_data = 1;
+               if (f)
+                       pclose(f);
+       }
+
+       if (do_unlink) {
+               unlink(xauthfile);
+               rmdir(xauthdir);
+       }
+       if (xauthdir)
+               xfree(xauthdir);
+       if (xauthfile)
+               xfree(xauthfile);
+
+       /*
+        * If we didn't get authentication data, just make up some
+        * data.  The forwarding code will check the validity of the
+        * response anyway, and substitute this data.  The X11
+        * server, however, will ignore this fake data and use
+        * whatever authentication mechanisms it was using otherwise
+        * for the local connection.
+        */
+       if (!got_data) {
+               u_int32_t rnd = 0;
+
+               logit("Warning: No xauth data; "
+                   "using fake authentication data for X11 forwarding.");
+               strlcpy(proto, SSH_X11_PROTO, sizeof proto);
+               for (i = 0; i < 16; i++) {
+                       if (i % 4 == 0)
+                               rnd = arc4random();
+                       snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
+                           rnd & 0xff);
+                       rnd >>= 8;
+               }
+       }
+}
+
 /*
  * This is called when the interactive is entered.  This checks if there is
  * an EOF coming on stdin.  We must check this explicitly, as select() does
@@ -528,6 +646,7 @@ static void
 client_extra_session2_setup(int id, void *arg)
 {
        struct confirm_ctx *cctx = arg;
+       const char *display;
        Channel *c;
        int i;
 
@@ -536,6 +655,24 @@ client_extra_session2_setup(int id, void *arg)
        if ((c = channel_lookup(id)) == NULL)
                fatal("%s: no channel for id %d", __func__, id);
 
+       display = getenv("DISPLAY");
+       if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
+               char *proto, *data;
+               /* Get reasonable local authentication information. */
+               client_x11_get_proto(display, options.xauth_location,
+                   options.forward_x11_trusted, &proto, &data);
+               /* Request forwarding with authentication spoofing. */
+               debug("Requesting X11 forwarding with authentication spoofing.");
+               x11_request_forwarding_with_spoofing(id, display, proto, data);
+               /* XXX wait for reply */
+       }
+
+       if (cctx->want_agent_fwd && options.forward_agent) {
+               debug("Requesting authentication agent forwarding.");
+               channel_request_start(id, "auth-agent-req@openssh.com", 0);
+               packet_send();
+       }
+
        client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
            cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env,
            client_subsystem_reply);
@@ -556,12 +693,12 @@ client_process_control(fd_set * readset)
 {
        Buffer m;
        Channel *c;
-       int client_fd, new_fd[3], ver, i, allowed;
+       int client_fd, new_fd[3], ver, allowed;
        socklen_t addrlen;
        struct sockaddr_storage addr;
        struct confirm_ctx *cctx;
        char *cmd;
-       u_int len, env_len, command, flags;
+       u_int i, len, env_len, command, flags;
        uid_t euid;
        gid_t egid;
 
@@ -601,7 +738,7 @@ client_process_control(fd_set * readset)
                buffer_free(&m);
                return;
        }
-       if ((ver = buffer_get_char(&m)) != 1) {
+       if ((ver = buffer_get_char(&m)) != SSHMUX_VER) {
                error("%s: wrong client version %d", __func__, ver);
                buffer_free(&m);
                close(client_fd);
@@ -616,24 +753,26 @@ client_process_control(fd_set * readset)
 
        switch (command) {
        case SSHMUX_COMMAND_OPEN:
-               if (options.control_master == 2)
+               if (options.control_master == SSHCTL_MASTER_ASK ||
+                   options.control_master == SSHCTL_MASTER_AUTO_ASK)
                        allowed = ask_permission("Allow shared connection "
                            "to %s? ", host);
                /* continue below */
                break;
        case SSHMUX_COMMAND_TERMINATE:
-               if (options.control_master == 2)
+               if (options.control_master == SSHCTL_MASTER_ASK ||
+                   options.control_master == SSHCTL_MASTER_AUTO_ASK)
                        allowed = ask_permission("Terminate shared connection "
                            "to %s? ", host);
                if (allowed)
                        quit_pending = 1;
-               /* FALLTHROUGH */       
+               /* 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) {
+               if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) {
                        error("%s: client msg_send failed", __func__);
                        close(client_fd);
                        buffer_free(&m);
@@ -653,7 +792,7 @@ client_process_control(fd_set * readset)
        buffer_clear(&m);
        buffer_put_int(&m, allowed);
        buffer_put_int(&m, getpid());
-       if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
+       if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) {
                error("%s: client msg_send failed", __func__);
                close(client_fd);
                buffer_free(&m);
@@ -674,7 +813,7 @@ client_process_control(fd_set * readset)
                buffer_free(&m);
                return;
        }
-       if ((ver = buffer_get_char(&m)) != 1) {
+       if ((ver = buffer_get_char(&m)) != SSHMUX_VER) {
                error("%s: wrong client version %d", __func__, ver);
                buffer_free(&m);
                close(client_fd);
@@ -685,6 +824,8 @@ client_process_control(fd_set * readset)
        memset(cctx, 0, sizeof(*cctx));
        cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0;
        cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0;
+       cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0;
+       cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 0;
        cctx->term = buffer_get_string(&m, &len);
 
        cmd = buffer_get_string(&m, &len);
@@ -718,7 +859,7 @@ client_process_control(fd_set * readset)
 
        /* This roundtrip is just for synchronisation of ttymodes */
        buffer_clear(&m);
-       if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
+       if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) {
                error("%s: client msg_send failed", __func__);
                close(client_fd);
                close(new_fd[0]);
@@ -786,6 +927,15 @@ process_cmdline(void)
                logit("      -Lport:host:hostport    Request local forward");
                logit("      -Rport:host:hostport    Request remote forward");
                logit("      -KRhostport             Cancel remote forward");
+               if (!options.permit_local_command)
+                       goto out;
+               logit("      !args                   Execute local command");
+               goto out;
+       }
+
+       if (*s == '!' && options.permit_local_command) {
+               s++;
+               ssh_local_cmd(s);
                goto out;
        }
 
@@ -866,7 +1016,10 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
        u_char ch;
        char *s;
 
-       for (i = 0; i < len; i++) {
+       if (len <= 0)
+               return (0);
+
+       for (i = 0; i < (u_int)len; i++) {
                /* Get one character at a time. */
                ch = buf[i];
 
@@ -1245,10 +1398,10 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
                session_ident = ssh2_chan_id;
                if (escape_char != SSH_ESCAPECHAR_NONE)
                        channel_register_filter(session_ident,
-                           simple_escape_filter);
+                           simple_escape_filter, NULL);
                if (session_ident != -1)
                        channel_register_cleanup(session_ident,
-                           client_channel_closed);
+                           client_channel_closed, 0);
        } else {
                /* Check if we should immediately send eof on stdin. */
                client_check_initial_eof_on_stdin();
@@ -1547,7 +1700,7 @@ client_request_x11(const char *request_type, int rchan)
 
        if (!options.forward_x11) {
                error("Warning: ssh server tried X11 forwarding.");
-               error("Warning: this is probably a break in attempt by a malicious server.");
+               error("Warning: this is probably a break-in attempt by a malicious server.");
                return NULL;
        }
        originator = packet_get_string(NULL);
@@ -1580,7 +1733,7 @@ client_request_agent(const char *request_type, int rchan)
 
        if (!options.forward_agent) {
                error("Warning: ssh server tried agent forwarding.");
-               error("Warning: this is probably a break in attempt by a malicious server.");
+               error("Warning: this is probably a break-in attempt by a malicious server.");
                return NULL;
        }
        sock =  ssh_get_authentication_socket();
@@ -1749,7 +1902,7 @@ client_session2_setup(int id, int want_tty, int want_subsystem,
                        /* Split */
                        name = xstrdup(env[i]);
                        if ((val = strchr(name, '=')) == NULL) {
-                               free(name);
+                               xfree(name);
                                continue;
                        }
                        *val++ = '\0';
@@ -1763,7 +1916,7 @@ client_session2_setup(int id, int want_tty, int want_subsystem,
                        }
                        if (!matched) {
                                debug3("Ignored env %s", name);
-                               free(name);
+                               xfree(name);
                                continue;
                        }
 
@@ -1772,7 +1925,7 @@ client_session2_setup(int id, int want_tty, int want_subsystem,
                        packet_put_cstring(name);
                        packet_put_cstring(val);
                        packet_send();
-                       free(name);
+                       xfree(name);
                }
        }
 
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