[libav-stable] h264: reset ref count if decoding the slice header fails

Anton Khirnov git at libav.org
Sat Jan 18 20:58:16 CET 2014


Module: libav
Branch: master
Commit: 0652e024c680420d298cdf3719d0a0c030173fe3

Author:    Anton Khirnov <anton at khirnov.net>
Committer: Anton Khirnov <anton at khirnov.net>
Date:      Thu Nov 28 10:54:35 2013 +0100

h264: reset ref count if decoding the slice header fails

Otherwise the ER code might try to use some already freed references.

Fixes possible access to freed memory.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable at libav.org

---

 libavcodec/h264.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index ed5aea8..6f329aa 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -4813,9 +4813,10 @@ again:
                 context_count = 0;
             }
 
-            if (err < 0)
+            if (err < 0) {
                 av_log(h->avctx, AV_LOG_ERROR, "decode_slice_header error\n");
-            else if (err == 1) {
+                h->ref_count[0] = h->ref_count[1] = h->list_count = 0;
+            } else if (err == 1) {
                 /* Slice could not be decoded in parallel mode, copy down
                  * NAL unit stuff to context 0 and restart. Note that
                  * rbsp_buffer is not transferred, but since we no longer



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