[SCM] libav/wheezy-security: h264: reset data partitioning at the beginning of each decode call

[siretart at users.alioth.debian.org]

The following commit has been merged in the wheezy-security branch:
commit 27ac9585c97d35b809382be5634c8e5f7211243a
Author: 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

diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index 1c2f23a..bca9bda 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -4017,6 +4017,13 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size){
             }
             break;
         case NAL_DPA:
+            if (s->flags2 & CODEC_FLAG2_CHUNKS) {
+                av_log(h->s.avctx, AV_LOG_ERROR,
+                       "Decoding in chunks is not supported for "
+                       "partitioned slices.\n");
+                return AVERROR(ENOSYS);
+            }
+
             init_get_bits(&hx->s.gb, ptr, bit_length);
             hx->intra_gb_ptr=
             hx->inter_gb_ptr= NULL;
@@ -4170,6 +4177,9 @@ static int decode_frame(AVCodecContext *avctx,
 
     s->flags= avctx->flags;
     s->flags2= avctx->flags2;
+    /* reset data partitioning here, to ensure GetBitContexts from previous
+     * packets do not get used. */
+    s->data_partitioning = 0;
 
    /* end of stream, output what is still in the buffers */
  out:

-- 
Libav/FFmpeg packaging