[FFmpeg-cvslog] lzo: Handle integer overflow

[Luca Barbato]

ffmpeg | branch: release/0.10 | Luca Barbato <lu_zero at gentoo.org> | Thu Jun 19 23:26:58 2014 +0200| [e7f5dacd55deeee8a866020b8463f829b2c5971f] | committer: Luca Barbato

lzo: Handle integer overflow

get_len can overflow for specially crafted payload.

Reported-By: Don A. Baley <donb at securitymouse.com>
CC: libav-stable at libav.org
(cherry picked from commit ccda51b14c0fcae2fad73a24872dce75a7964996)
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>

Conflicts:
	libavutil/lzo.c

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e7f5dacd55deeee8a866020b8463f829b2c5971f
---

 libavutil/lzo.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/libavutil/lzo.c b/libavutil/lzo.c
index e49b83e..0c497a5 100644
--- a/libavutil/lzo.c
+++ b/libavutil/lzo.c
@@ -88,6 +88,10 @@ static inline int get_len(LZOContext *c, int x, int mask) {
 static inline void copy(LZOContext *c, int cnt) {
     register const uint8_t *src = c->in;
     register uint8_t *dst = c->out;
+    if (cnt < 0) {
+        c->error |= AV_LZO_ERROR;
+        return;
+    }
     if (cnt > c->in_end - src) {
         cnt = FFMAX(c->in_end - src, 0);
         c->error |= AV_LZO_INPUT_DEPLETED;
@@ -113,13 +117,17 @@ static inline void memcpy_backptr(uint8_t *dst, int back, int cnt);
 /**
  * @brief Copies previously decoded bytes to current position.
  * @param back how many bytes back we start
- * @param cnt number of bytes to copy, must be >= 0
+ * @param cnt number of bytes to copy, must be > 0
  *
  * cnt > back is valid, this will copy the bytes we just copied,
  * thus creating a repeating pattern with a period length of back.
  */
 static inline void copy_backptr(LZOContext *c, int back, int cnt) {
     register uint8_t *dst = c->out;
+    if (cnt <= 0) {
+        c->error |= AV_LZO_ERROR;
+        return;
+    }
     if (dst - c->out_start < back) {
         c->error |= AV_LZO_INVALID_BACKPTR;
         return;