debian/patches/CVE-2014-8xxx/0020-glx-Be-more-paranoid-about-variable-length-requests-.patch

   1 From 096a5af8e52faafc38ae84dd17bede7ac03a3b83 Mon Sep 17 00:00:00 2001
   2 From: Adam Jackson <ajax@redhat.com>
   3 Date: Mon, 10 Nov 2014 12:13:36 -0500
   4 Subject: [PATCH 20/33] glx: Be more paranoid about variable-length requests
   5  [CVE-2014-8093 1/6]
   6
   7 If the size computation routine returns -1 we should just reject the
   8 request outright.  Clamping it to zero could give an attacker the
   9 opportunity to also mangle cmdlen in such a way that the subsequent
  10 length check passes, and the request would get executed, thus passing
  11 data we wanted to reject to the renderer.
  12
  13 Reviewed-by: Keith Packard <keithp@keithp.com>
  14 Reviewed-by: Julien Cristau <jcristau@debian.org>
  15 Reviewed-by: Michal Srb <msrb@suse.com>
  16 Reviewed-by: Andy Ritger <aritger@nvidia.com>
  17 Signed-off-by: Adam Jackson <ajax@redhat.com>
  18 Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
  19 ---
  20  glx/glxcmds.c |    4 ++--
  21  1 file changed, 2 insertions(+), 2 deletions(-)
  22
  23 Index: xorg-server-1.15.1/glx/glxcmds.c
  24 ===================================================================
  25 --- xorg-server-1.15.1.orig/glx/glxcmds.c       2014-12-04 11:55:22.293001486 -0500
  26 +++ xorg-server-1.15.1/glx/glxcmds.c    2014-12-04 11:55:22.289001461 -0500
  27 @@ -2052,7 +2052,7 @@
  28              extra = (*entry.varsize) (pc + __GLX_RENDER_HDR_SIZE,
  29                                        client->swapped);
  30              if (extra < 0) {
  31 -                extra = 0;
  32 +                return BadLength;
  33              }
  34              if (cmdlen != __GLX_PAD(entry.bytes + extra)) {
  35                  return BadLength;
  36 @@ -2169,7 +2169,7 @@
  37              extra = (*entry.varsize) (pc + __GLX_RENDER_LARGE_HDR_SIZE,
  38                                        client->swapped);
  39              if (extra < 0) {
  40 -                extra = 0;
  41 +                return BadLength;
  42              }
  43              /* large command's header is 4 bytes longer, so add 4 */
  44              if (cmdlen != __GLX_PAD(entry.bytes + 4 + extra)) {