File U_glx_Be_more_paranoid_about_variable_length_re... of Package xorg-x11-server

Overview Repositories Revisions Requests Users Attributes Meta

File U_glx_Be_more_paranoid_about_variable_length_requests.patch of Package xorg-x11-server

Subject: glx: Be more paranoid about variable-length requests
References: bnc#907268, CVE-2014-8093
Patch-Mainline: Upstream
Signed-off-by: Michal Srb <msrb@suse.com>

If the size computation routine returns -1 we should just reject the
request outright.  Clamping it to zero could give an attacker the
opportunity to also mangle cmdlen in such a way that the subsequent
length check passes, and the request would get executed, thus passing
data we wanted to reject to the renderer.

Reviewed-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Julien Cristau <jcristau@debian.org>
Reviewed-by: Michal Srb <msrb@suse.com>
Reviewed-by: Andy Ritger <aritger@nvidia.com>
Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
---
 glx/glxcmds.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/glx/glxcmds.c b/glx/glxcmds.c
index 8d3fa9f..0521b58 100644
--- a/glx/glxcmds.c
+++ b/glx/glxcmds.c
@@ -2060,7 +2060,7 @@ __glXDisp_Render(__GLXclientState * cl, GLbyte * pc)
             extra = (*entry.varsize) (pc + __GLX_RENDER_HDR_SIZE,
                                       client->swapped);
             if (extra < 0) {
-                extra = 0;
+                return BadLength;
             }
             if (cmdlen != __GLX_PAD(entry.bytes + extra)) {
                 return BadLength;
@@ -2177,7 +2177,7 @@ __glXDisp_RenderLarge(__GLXclientState * cl, GLbyte * pc)
             extra = (*entry.varsize) (pc + __GLX_RENDER_LARGE_HDR_SIZE,
                                       client->swapped);
             if (extra < 0) {
-                extra = 0;
+                return BadLength;
             }
             /* large command's header is 4 bytes longer, so add 4 */
             if (cmdlen != __GLX_PAD(entry.bytes + 4 + extra)) {
-- 
1.7.9.2

Places

File U_glx_Be_more_paranoid_about_variable_length_requests.patch of Package xorg-x11-server

Places