[libav-stable] h264: prevent two matching fields from being both a short/ long ref combination

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


Module: libav
Branch: master
Commit: 98cc9efc5f6b4dc847ed3b9b60b1c3bcd14e6791

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

h264: prevent two matching fields from being both a short/long ref combination

Fixes possible access to freed memory.

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

---

 libavcodec/h264_refs.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/h264_refs.c b/libavcodec/h264_refs.c
index bba77d1..88aaac7 100644
--- a/libavcodec/h264_refs.c
+++ b/libavcodec/h264_refs.c
@@ -621,6 +621,8 @@ int ff_h264_execute_ref_pic_marking(H264Context *h, MMCO *mmco, int mmco_count)
                      * Report the problem and keep the pair where it is,
                      * and mark this field valid.
                      */
+            if (h->short_ref[0] == h->cur_pic_ptr)
+                remove_short_at_index(h, 0);
 
             if (h->long_ref[mmco[i].long_arg] != h->cur_pic_ptr) {
                 remove_long(h, mmco[i].long_arg, 0);



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