integer overflow in XResQueryClientResources() [CVE-2013-1988 2/2]

The CARD32 rep.num_types needs to be bounds checked before multiplying
by sizeof(XResType) 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, 6 insertions, 1 deletions

diff --git a/src/XRes.c b/src/XRes.c
index 5117321..ff21dd4 100644
--- a/src/XRes.c
+++ b/src/XRes.c
@@ -186,7 +186,12 @@ Status XResQueryClientResources (
     }
 
     if(rep.num_types) {
-        if((typs = Xmalloc(sizeof(XResType) * rep.num_types))) {
+        if (rep.num_types < (INT_MAX / sizeof(XResType)))
+            typs = Xmalloc(sizeof(XResType) * rep.num_types);
+        else
+            typs = NULL;
+
+        if (typs != NULL) {
             xXResType scratch;
             int i;