From c77be3a35a0160d6af88056b0899f120f2eef38e Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Tue, 24 Jan 2012 20:54:27 +0100
Subject: [PATCH] error concealment: initialize block index.
Fixes CVE-2011-3941 (out of bounds write)
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
libavcodec/error_resilience.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/libavcodec/error_resilience.c b/libavcodec/error_resilience.c
index 8bb5d0c0dec..d55c0006efd 100644
--- a/libavcodec/error_resilience.c
+++ b/libavcodec/error_resilience.c
@@ -46,6 +46,9 @@ static void decode_mb(MpegEncContext *s, int ref)
s->dest[1] = s->current_picture.f.data[1] + (s->mb_y * (16 >> s->chroma_y_shift) * s->uvlinesize) + s->mb_x * (16 >> s->chroma_x_shift);
s->dest[2] = s->current_picture.f.data[2] + (s->mb_y * (16 >> s->chroma_y_shift) * s->uvlinesize) + s->mb_x * (16 >> s->chroma_x_shift);
+ ff_init_block_index(s);
+ ff_update_block_index(s);
+
if (CONFIG_H264_DECODER && s->codec_id == CODEC_ID_H264) {
H264Context *h = (void*)s;
h->mb_xy = s->mb_x + s->mb_y * s->mb_stride;
--
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