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

[Michael Niedermayer]

ffmpeg | branch: release/0.8 | Michael Niedermayer <michaelni at gmx.at> | Fri Jan 25 06:11:59 2013 +0100| [2cac35086c9e103fa98960c546d5017e7363803a] | committer: Michael Niedermayer

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>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2cac35086c9e103fa98960c546d5017e7363803a
---

 libavcodec/vqavideo.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/libavcodec/vqavideo.c b/libavcodec/vqavideo.c
index d1eab5b..6e1ce6c 100644
--- a/libavcodec/vqavideo.c
+++ b/libavcodec/vqavideo.c
@@ -527,6 +527,11 @@ static void vqa_decode_chunk(VqaContext *s)
         chunk_size = AV_RB32(&s->buf[cbp0_chunk + 4]);
         cbp0_chunk += CHUNK_PREAMBLE_SIZE;
 
+        if (chunk_size > MAX_CODEBOOK_SIZE - s->next_codebook_buffer_index) {
+            av_log(s->avctx, AV_LOG_ERROR, "cbp0 chunk too large (0x%X bytes)\n", chunk_size);
+            return AVERROR_INVALIDDATA;
+        }
+
         /* accumulate partial codebook */
         memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
             &s->buf[cbp0_chunk], chunk_size);
@@ -550,6 +555,11 @@ static void vqa_decode_chunk(VqaContext *s)
         chunk_size = AV_RB32(&s->buf[cbpz_chunk + 4]);
         cbpz_chunk += CHUNK_PREAMBLE_SIZE;
 
+        if (chunk_size > MAX_CODEBOOK_SIZE - s->next_codebook_buffer_index) {
+            av_log(s->avctx, AV_LOG_ERROR, "cbpz chunk too large (0x%X bytes)\n", chunk_size);
+            return AVERROR_INVALIDDATA;
+        }
+
         /* accumulate partial codebook */
         memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
             &s->buf[cbpz_chunk], chunk_size);