integer overflow in XvMCListSubpictureTypes() [CVE-2013-1990 2/2]

rep.num is a CARD32 and needs to be bounds checked before multiplying by
sizeof(XvImageFormatValues) 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.

Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/XvMC.c b/src/XvMC.c
index 5d8c2cf..8d602ec 100644
--- a/src/XvMC.c
+++ b/src/XvMC.c
@@ -184,8 +184,8 @@ XvImageFormatValues * XvMCListSubpictureTypes (
     }
 
     if(rep.num > 0) {
-        ret =
-	   (XvImageFormatValues*)Xmalloc(rep.num * sizeof(XvImageFormatValues));
+        if (rep.num < (INT_MAX / sizeof(XvImageFormatValues)))
+            ret = Xmalloc(rep.num * sizeof(XvImageFormatValues));
 
         if(ret) {
             xvImageFormatInfo Info;