[PATCH] libXvMC: avoid overflowing by making nameLen and busIDLen addition overflow

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

Al Viro pointed this out on lwn, and I think this patch should fix it,
but making sure we don't do the addition as 32-bit on 64-bit machines.

Reported-by: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/XvMC.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/XvMC.c b/src/XvMC.c
index 74c8b85..e1b215e 100644
--- a/src/XvMC.c
+++ b/src/XvMC.c
@@ -575,7 +575,7 @@ Status XvMCGetDRInfo(Display *dpy, XvPortID port,
 
 	if (rep.length < (INT_MAX >> 2)) {
 	    realSize = rep.length << 2;
-	    if (realSize >= (rep.nameLen + rep.busIDLen)) {
+	    if (realSize >= ((unsigned long)rep.nameLen + (unsigned long)rep.busIDLen)) {
 		tmpBuf = Xmalloc(realSize);
 		*name = Xmalloc(rep.nameLen);
 		*busID = Xmalloc(rep.busIDLen);
-- 
1.8.1.2