Mesa (9.0): integer overflow in XF86DRIOpenConnection() [CVE-2013-1993 1/2]

[Ian Romanick]

Module: Mesa
Branch: 9.0
Commit: ee30fd0ea0437ab930f85f5ed335a44edc3ef12e
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=ee30fd0ea0437ab930f85f5ed335a44edc3ef12e

Author: Alan Coopersmith <alan.coopersmith at oracle.com>
Date:   Fri Apr 26 16:31:58 2013 -0700

integer overflow in XF86DRIOpenConnection() [CVE-2013-1993 1/2]

busIdStringLength is a CARD32 and needs to be bounds checked before adding
one to it to come up with the total size to allocate, to avoid integer
overflow leading to underallocation and writing data from the network past
the end of the allocated buffer.

NOTE: This is a candidate for stable release branches.

Reported-by: Ilja Van Sprundel <ivansprundel at ioactive.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith at oracle.com>
Reviewed-by: Brian Paul <brianp at vmware.com>
(cherry picked from commit 2e5a268f18be30df15aed0b44b01a18a37fb5df4)

---

 src/glx/XF86dri.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/src/glx/XF86dri.c b/src/glx/XF86dri.c
index 5c181d6..c7c80c1 100644
--- a/src/glx/XF86dri.c
+++ b/src/glx/XF86dri.c
@@ -43,6 +43,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <X11/extensions/Xext.h>
 #include <X11/extensions/extutil.h>
 #include "xf86dristr.h"
+#include <limits.h>
 
 static XExtensionInfo _xf86dri_info_data;
 static XExtensionInfo *xf86dri_info = &_xf86dri_info_data;
@@ -201,7 +202,11 @@ XF86DRIOpenConnection(Display * dpy, int screen, drm_handle_t * hSAREA,
    }
 
    if (rep.length) {
-      if (!(*busIdString = (char *) Xcalloc(rep.busIdStringLength + 1, 1))) {
+      if (rep.busIdStringLength < INT_MAX)
+         *busIdString = (char *) Xcalloc(rep.busIdStringLength + 1, 1);
+      else
+         *busIdString = NULL;
+      if (*busIdString == NULL) {
          _XEatData(dpy, ((rep.busIdStringLength + 3) & ~3));
          UnlockDisplay(dpy);
          SyncHandle();