- (djm) [auth-pam.c sftp.c] spaces vs. tabs at start of line

   - djm@cvs.openbsd.org 2005/07/17 06:49:04
     [channels.c channels.h session.c session.h]
     Fix a number of X11 forwarding channel leaks:
     1. Refuse multiple X11 forwarding requests on the same session
     2. Clean up all listeners after a single_connection X11 forward, not just
        the one that made the single connection
     3. Destroy X11 listeners when the session owning them goes away
     testing and ok dtucker@

5 files changed, 125 insertions, 8 deletions

diff --git a/ChangeLog b/ChangeLog
index 647ad0160..84b82cccc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,14 @@
    [cipher-acss.c loginrec.c ssh-rand-helper.c sshd.c] Fix whitespace at EOL 
    in portable too ("perl -p -i -e 's/\s+$/\n/' *.[ch]")
  - (djm) [auth-pam.c sftp.c] spaces vs. tabs at start of line
+   - djm@cvs.openbsd.org 2005/07/17 06:49:04
+     [channels.c channels.h session.c session.h]
+     Fix a number of X11 forwarding channel leaks:
+     1. Refuse multiple X11 forwarding requests on the same session
+     2. Clean up all listeners after a single_connection X11 forward, not just
+        the one that made the single connection
+     3. Destroy X11 listeners when the session owning them goes away
+     testing and ok dtucker@
 
 20050716
  - (dtucker) [auth-pam.c] Ensure that only one side of the authentication
@@ -2841,4 +2849,4 @@
    - (djm) Trim deprecated options from INSTALL. Mention UsePAM
    - (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
 
-$Id: ChangeLog,v 1.3849 2005/07/17 07:18:49 djm Exp $
+$Id: ChangeLog,v 1.3850 2005/07/17 07:19:24 djm Exp $
diff --git a/channels.c b/channels.c
index b7ff85007..8da399b69 100644
--- a/channels.c
+++ b/channels.c
@@ -39,7 +39,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: channels.c,v 1.221 2005/07/16 01:35:24 djm Exp $");
+RCSID("$OpenBSD: channels.c,v 1.222 2005/07/17 06:49:04 djm Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -2659,7 +2659,7 @@ channel_send_window_changes(void)
  */
 int
 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
-    int single_connection, u_int *display_numberp)
+    int single_connection, u_int *display_numberp, int **chanids)
 {
         Channel *nc = NULL;
         int display_number, sock;
@@ -2749,6 +2749,8 @@ x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
         }
 
         /* Allocate a channel for each socket. */
+        if (chanids != NULL)
+                *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1));
         for (n = 0; n < num_socks; n++) {
                 sock = socks[n];
                 nc = channel_new("x11 listener",
@@ -2756,7 +2758,11 @@ x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
                     CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
                     0, "X11 inet listener", 1);
                 nc->single_connection = single_connection;
+                if (*chanids != NULL)
+                        (*chanids)[n] = nc->self;
         }
+        if (*chanids != NULL)
+                (*chanids)[n] = -1;
 
         /* Return the display number for the DISPLAY environment variable. */
         *display_numberp = display_number;
diff --git a/channels.h b/channels.h
index b89b7c95d..1cb2c3a34 100644
--- a/channels.h
+++ b/channels.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: channels.h,v 1.78 2005/07/08 09:41:33 markus Exp $    */
+/*      $OpenBSD: channels.h,v 1.79 2005/07/17 06:49:04 djm Exp $       */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -214,7 +214,7 @@ int	 channel_cancel_rport_listener(const char *, u_short);
 /* x11 forwarding */
 
 int      x11_connect_display(void);
-int      x11_create_display_inet(int, int, int, u_int *);
+int      x11_create_display_inet(int, int, int, u_int *, int **);
 void     x11_input_open(int, u_int32_t, void *);
 void     x11_request_forwarding_with_spoofing(int, const char *, const char *,
             const char *);
diff --git a/session.c b/session.c
index 13c3b001f..81d7d53e8 100644
--- a/session.c
+++ b/session.c
@@ -33,7 +33,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: session.c,v 1.183 2005/07/16 01:35:24 djm Exp $");
+RCSID("$OpenBSD: session.c,v 1.184 2005/07/17 06:49:04 djm Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -1634,6 +1634,7 @@ session_new(void)
                         s->ttyfd = -1;
                         s->used = 1;
                         s->self = i;
+                        s->x11_chanids = NULL;
                         debug("session_new: session %d", i);
                         return s;
                 }
@@ -1707,6 +1708,29 @@ session_by_channel(int id)
 }
 
 static Session *
+session_by_x11_channel(int id)
+{
+        int i, j;
+
+        for (i = 0; i < MAX_SESSIONS; i++) {
+                Session *s = &sessions[i];
+
+                if (s->x11_chanids == NULL || !s->used)
+                        continue;
+                for (j = 0; s->x11_chanids[j] != -1; j++) {
+                        if (s->x11_chanids[j] == id) {
+                                debug("session_by_x11_channel: session %d "
+                                    "channel %d", s->self, id);
+                                return s;
+                        }
+                }
+        }
+        debug("session_by_x11_channel: unknown channel %d", id);
+        session_dump();
+        return NULL;
+}
+
+static Session *
 session_by_pid(pid_t pid)
 {
         int i;
@@ -1835,6 +1859,11 @@ session_x11_req(Session *s)
 {
         int success;
 
+        if (s->auth_proto != NULL || s->auth_data != NULL) {
+                error("session_x11_req: session %d: "
+                    "x11 fowarding already active", s->self);
+                return 0;
+        }
         s->single_connection = packet_get_char();
         s->auth_proto = packet_get_string(NULL);
         s->auth_data = packet_get_string(NULL);
@@ -2060,9 +2089,66 @@ sig2name(int sig)
 }
 
 static void
+session_close_x11(int id)
+{
+        Channel *c;
+
+        if ((c = channel_lookup(id)) == NULL) {
+                debug("session_close_x11: x11 channel %d missing", id);
+        } else {
+                /* Detach X11 listener */
+                debug("session_close_x11: detach x11 channel %d", id);
+                channel_cancel_cleanup(id);
+                if (c->ostate != CHAN_OUTPUT_CLOSED)
+                        chan_mark_dead(c);
+        }
+}
+
+static void
+session_close_single_x11(int id, void *arg)
+{
+        Session *s;
+        u_int i;
+
+        debug3("session_close_single_x11: channel %d", id);
+        channel_cancel_cleanup(id);
+        if ((s  = session_by_x11_channel(id)) == NULL)
+                fatal("session_close_single_x11: no x11 channel %d", id);
+        for (i = 0; s->x11_chanids[i] != -1; i++) {
+                debug("session_close_single_x11: session %d: "
+                    "closing channel %d", s->self, s->x11_chanids[i]);
+                /*
+                 * The channel "id" is already closing, but make sure we
+                 * close all of its siblings.
+                 */
+                if (s->x11_chanids[i] != id)
+                        session_close_x11(s->x11_chanids[i]);
+        }
+        xfree(s->x11_chanids);
+        s->x11_chanids = NULL;
+        if (s->display) {
+                xfree(s->display);
+                s->display = NULL;
+        }
+        if (s->auth_proto) {
+                xfree(s->auth_proto);
+                s->auth_proto = NULL;
+        }
+        if (s->auth_data) {
+                xfree(s->auth_data);
+                s->auth_data = NULL;
+        }
+        if (s->auth_display) {
+                xfree(s->auth_display);
+                s->auth_display = NULL;
+        }
+}
+
+static void
 session_exit_message(Session *s, int status)
 {
         Channel *c;
+        u_int i;
 
         if ((c = channel_lookup(s->chanid)) == NULL)
                 fatal("session_exit_message: session %d: no channel %d",
@@ -2102,6 +2188,14 @@ session_exit_message(Session *s, int status)
         if (c->ostate != CHAN_OUTPUT_CLOSED)
                 chan_write_failed(c);
         s->chanid = -1;
+
+        /* Close any X11 listeners associated with this session */
+        if (s->x11_chanids != NULL) {
+                for (i = 0; s->x11_chanids[i] != -1; i++) {
+                        session_close_x11(s->x11_chanids[i]);
+                        s->x11_chanids[i] = -1;
+                }
+        }
 }
 
 void
@@ -2116,6 +2210,8 @@ session_close(Session *s)
                 xfree(s->term);
         if (s->display)
                 xfree(s->display);
+        if (s->x11_chanids)
+                xfree(s->x11_chanids);
         if (s->auth_display)
                 xfree(s->auth_display);
         if (s->auth_data)
@@ -2154,6 +2250,7 @@ void
 session_close_by_channel(int id, void *arg)
 {
         Session *s = session_by_channel(id);
+
         if (s == NULL) {
                 debug("session_close_by_channel: no session for id %d", id);
                 return;
@@ -2234,6 +2331,7 @@ session_setup_x11fwd(Session *s)
         struct stat st;
         char display[512], auth_display[512];
         char hostname[MAXHOSTNAMELEN];
+        u_int i;
 
         if (no_x11_forwarding_flag) {
                 packet_send_debug("X11 forwarding disabled in user configuration file.");
@@ -2259,10 +2357,14 @@ session_setup_x11fwd(Session *s)
         }
         if (x11_create_display_inet(options.x11_display_offset,
             options.x11_use_localhost, s->single_connection,
-            &s->display_number) == -1) {
+            &s->display_number, &s->x11_chanids) == -1) {
                 debug("x11_create_display_inet failed.");
                 return 0;
         }
+        for (i = 0; s->x11_chanids[i] != -1; i++) {
+                channel_register_cleanup(s->x11_chanids[i],
+                    session_close_single_x11);
+        }
 
         /* Set up a suitable value for the DISPLAY variable. */
         if (gethostname(hostname, sizeof(hostname)) < 0)
diff --git a/session.h b/session.h
index 92bd16573..a2598a99c 100644
--- a/session.h
+++ b/session.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: session.h,v 1.24 2005/06/17 02:44:33 djm Exp $        */
+/*      $OpenBSD: session.h,v 1.25 2005/07/17 06:49:04 djm Exp $        */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -49,6 +49,7 @@ struct Session {
         int     single_connection;
         /* proto 2 */
         int     chanid;
+        int     *x11_chanids;
         int     is_subsystem;
         u_int   num_env;
         struct {