avutil/lzo: Fix integer overflow

Embargoed-till: 2014-06-27 requested by researcher, but embargo broken by libav today (git and mailing list)

Fixes: LMS-2014-06-16-4
Found-by: "Don A. Bailey" <donb@securitymouse.com>
See: ccda51b14c0fcae2fad73a24872dce75a7964996
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit d6af26c55c1ea30f85a7d9edbc373f53be1743ee)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 6 insertions, 1 deletions

diff --git a/libavutil/lzo.c b/libavutil/lzo.c
index 221a66b9ab..82dba94771 100644
--- a/libavutil/lzo.c
+++ b/libavutil/lzo.c
@@ -65,8 +65,13 @@ static inline int get_len(LZOContext *c, int x, int mask)
 {
     int cnt = x & mask;
     if (!cnt) {
-        while (!(x = get_byte(c)))
+        while (!(x = get_byte(c))) {
+            if (cnt >= INT_MAX - 1000) {
+                c->error |= AV_LZO_ERROR;
+                break;
+            }
             cnt += 255;
+        }
         cnt += mask + x;
     }
     return cnt;