[FFmpeg-cvslog] vqavideo: check chunk sizes before reading chunks

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Fri Jan 25 06:11:59 2013 +0100| [f7d18deb73d1dd1b27b2c7062c9a10d168a6c62a] | committer: Reinhard Tartler

vqavideo: check chunk sizes before reading chunks

Fixes out of array writes

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit ab6c9332bfa1e20127a16392a0b85a4aa4840889)

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit 13093f9767b922661132a3c1f4b5ba2c7338b660)

CC: libav-stable at libav.org

Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f7d18deb73d1dd1b27b2c7062c9a10d168a6c62a
---

 libavcodec/vqavideo.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/libavcodec/vqavideo.c b/libavcodec/vqavideo.c
index 22b024c..ae854cd 100644
--- a/libavcodec/vqavideo.c
+++ b/libavcodec/vqavideo.c
@@ -532,6 +532,12 @@ static int vqa_decode_chunk(VqaContext *s)
         bytestream2_seek(&s->gb, cbp0_chunk, SEEK_SET);
         chunk_size = bytestream2_get_be32(&s->gb);
 
+        if (chunk_size > MAX_CODEBOOK_SIZE - s->next_codebook_buffer_index) {
+            av_log(s->avctx, AV_LOG_ERROR, "cbp0 chunk too large (%u bytes)\n",
+                   chunk_size);
+            return AVERROR_INVALIDDATA;
+        }
+
         /* accumulate partial codebook */
         bytestream2_get_buffer(&s->gb, &s->next_codebook_buffer[s->next_codebook_buffer_index],
                                chunk_size);
@@ -555,6 +561,12 @@ static int vqa_decode_chunk(VqaContext *s)
         bytestream2_seek(&s->gb, cbpz_chunk, SEEK_SET);
         chunk_size = bytestream2_get_be32(&s->gb);
 
+        if (chunk_size > MAX_CODEBOOK_SIZE - s->next_codebook_buffer_index) {
+            av_log(s->avctx, AV_LOG_ERROR, "cbpz chunk too large (%u bytes)\n",
+                   chunk_size);
+            return AVERROR_INVALIDDATA;
+        }
+
         /* accumulate partial codebook */
         bytestream2_get_buffer(&s->gb, &s->next_codebook_buffer[s->next_codebook_buffer_index],
                                chunk_size);