[libav-stable] h264: reset data partitioning at the beginning of each decode call

Anton Khirnov git at libav.org
Tue Feb 4 11:29:58 CET 2014


Module: libav
Branch: master
Commit: 1f097d168d9cad473dd44010a337c1413a9cd198

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 data partitioning at the beginning of each decode call

Prevents using GetBitContexts with data from previous calls.

Fixes access to freed memory.

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

---

 libavcodec/h264.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index fd9f796..da2d4a5 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -1764,7 +1764,6 @@ static int decode_update_thread_context(AVCodecContext *dst,
     h->picture_structure    = h1->picture_structure;
     h->qscale               = h1->qscale;
     h->droppable            = h1->droppable;
-    h->data_partitioning    = h1->data_partitioning;
     h->low_delay            = h1->low_delay;
 
     for (i = 0; i < MAX_PICTURE_COUNT; i++) {
@@ -4745,6 +4744,13 @@ again:
                 }
                 break;
             case NAL_DPA:
+                if (h->avctx->flags & CODEC_FLAG2_CHUNKS) {
+                    av_log(h->avctx, AV_LOG_ERROR,
+                           "Decoding in chunks is not supported for "
+                           "partitioned slices.\n");
+                    return AVERROR(ENOSYS);
+                }
+
                 init_get_bits(&hx->gb, ptr, bit_length);
                 hx->intra_gb_ptr =
                 hx->inter_gb_ptr = NULL;
@@ -4894,6 +4900,9 @@ static int h264_decode_frame(AVCodecContext *avctx, void *data,
     int ret;
 
     h->flags = avctx->flags;
+    /* reset data partitioning here, to ensure GetBitContexts from previous
+     * packets do not get used. */
+    h->data_partitioning = 0;
 
     /* end of stream, output what is still in the buffers */
 out:



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