From: Ronald S. Bultje <rsbultje@gmail.com>
Date: Wed, 21 Mar 2012 22:19:31 +0000 (-0700)
Subject: vqa: check palette chunk size before reading data.
X-Git-Tag: android-x86-4.4-r1~8529^2~2495
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=75d7975268394f4f16294b68ec6d6d5ac30da3ac;p=android-x86%2Fexternal-ffmpeg.git

vqa: check palette chunk size before reading data.

Prevents overreads beyond buffer boundaries.

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

diff --git a/libavcodec/vqavideo.c b/libavcodec/vqavideo.c
index 2bb9e2f2f8..54699a0ade 100644
--- a/libavcodec/vqavideo.c
+++ b/libavcodec/vqavideo.c
@@ -396,7 +396,7 @@ static int vqa_decode_chunk(VqaContext *s)
         bytestream2_seek(&s->gb, cpl0_chunk, SEEK_SET);
         chunk_size = bytestream2_get_be32(&s->gb);
         /* sanity check the palette size */
-        if (chunk_size / 3 > 256) {
+        if (chunk_size / 3 > 256 || chunk_size > bytestream2_get_bytes_left(&s->gb)) {
             av_log(s->avctx, AV_LOG_ERROR, "  VQA video: problem: found a palette chunk with %d colors\n",
                 chunk_size / 3);
             return AVERROR_INVALIDDATA;