- markus@cvs.openbsd.org 2003/10/11 08:24:08

[openssh.git] / ssh.c

diff --git a/ssh.c b/ssh.c
index 35418f69335abe2c751bcdd36da4e2e48bb705e0..39d1b2f6a76baf0ac9442cf25510c79f8c198372 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -13,7 +13,7 @@
  * called by a name other than "ssh" or "Secure Shell".
  *
  * Copyright (c) 1999 Niels Provos.  All rights reserved.
- * Copyright (c) 2000, 2001, 2002 Markus Friedl.  All rights reserved.
+ * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  *
  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
  * in Canada (German citizen).
@@ -40,7 +40,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh.c,v 1.201 2003/09/01 18:15:50 markus Exp $");
+RCSID("$OpenBSD: ssh.c,v 1.202 2003/10/11 08:24:08 markus Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -155,6 +155,7 @@ usage(void)
        fprintf(stderr, "  -A          Enable authentication agent forwarding.\n");
        fprintf(stderr, "  -a          Disable authentication agent forwarding (default).\n");
        fprintf(stderr, "  -X          Enable X11 connection forwarding.\n");
+       fprintf(stderr, "  -Y          Enable trusted X11 connection forwarding.\n");
        fprintf(stderr, "  -x          Disable X11 connection forwarding (default).\n");
        fprintf(stderr, "  -i file     Identity for public key authentication "
            "(default: ~/.ssh/identity)\n");
@@ -264,7 +265,7 @@ main(int ac, char **av)
 
 again:
        while ((opt = getopt(ac, av,
-           "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:NPR:TVX")) != -1) {
+           "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:NPR:TVXY")) != -1) {
                switch (opt) {
                case '1':
                        options.protocol = SSH_PROTO_1;
@@ -291,6 +292,10 @@ again:
                case 'X':
                        options.forward_x11 = 1;
                        break;
+               case 'Y':
+                       options.forward_x11 = 1;
+                       options.forward_x11_trusted = 1;
+                       break;
                case 'g':
                        options.gateway_ports = 1;
                        break;
@@ -721,19 +726,25 @@ again:
        return exit_status;
 }
 
+#define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
+
 static void
 x11_get_proto(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, i;
-       char *display;
+       int got_data = 0, generated = 0, do_unlink = 0, i;
+       char *display, *xauthdir, *xauthfile;
        struct stat st;
 
+       xauthdir = xauthfile = NULL;
        *_proto = proto;
        *_data = data;
        proto[0] = data[0] = '\0';
+
        if (!options.xauth_location ||
            (stat(options.xauth_location, &st) == -1)) {
                debug("No xauth program.");
@@ -742,28 +753,59 @@ x11_get_proto(char **_proto, char **_data)
                        debug("x11_get_proto: DISPLAY not set");
                        return;
                }
-               /* Try to get Xauthority information for the display. */
-               if (strncmp(display, "localhost:", 10) == 0)
-                       /*
-                        * 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.
-                        */
-                       snprintf(line, sizeof line, "%s list unix:%s 2>"
-                           _PATH_DEVNULL, options.xauth_location, display+10);
-               else
-                       snprintf(line, sizeof line, "%s list %.200s 2>"
-                           _PATH_DEVNULL, options.xauth_location, display);
-               debug2("x11_get_proto: %s", line);
-               f = popen(line, "r");
+               /*
+                * 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 (options.forward_x11_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 120 2>" _PATH_DEVNULL,
+                                   options.xauth_location, 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,
+                   options.xauth_location,
+                   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
@@ -775,12 +817,14 @@ x11_get_proto(char **_proto, char **_data)
        if (!got_data) {
                u_int32_t rand = 0;
 
-               logit("Warning: No xauth data; using fake authentication data for X11 forwarding.");
-               strlcpy(proto, "MIT-MAGIC-COOKIE-1", sizeof proto);
+               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)
                                rand = arc4random();
-                       snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", rand & 0xff);
+                       snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
+                           rand & 0xff);
                        rand >>= 8;
                }
        }