[FFmpeg-cvslog] rv10: improve buffer size check.

[Anton Khirnov]

ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Sun Feb  3 08:42:02 2013 +0100| [605b047bcc48482dc8a356f56629da259fbddbf1] | committer: Anton Khirnov

rv10: improve buffer size check.

Check slice count and input buffer size before constructing a possibly
invalid pointer, not after.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=605b047bcc48482dc8a356f56629da259fbddbf1
---

 libavcodec/rv10.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libavcodec/rv10.c b/libavcodec/rv10.c
index 8cce6cf..38abf78 100644
--- a/libavcodec/rv10.c
+++ b/libavcodec/rv10.c
@@ -659,11 +659,15 @@ static int rv10_decode_frame(AVCodecContext *avctx,
     if(!avctx->slice_count){
         slice_count = (*buf++) + 1;
         buf_size--;
+
+        if (!slice_count || buf_size <= 8 * slice_count) {
+            av_log(avctx, AV_LOG_ERROR, "Invalid slice count: %d.\n", slice_count);
+            return AVERROR_INVALIDDATA;
+        }
+
         slices_hdr = buf + 4;
         buf += 8 * slice_count;
         buf_size -= 8 * slice_count;
-        if (buf_size <= 0)
-            return AVERROR_INVALIDDATA;
     }else
         slice_count = avctx->slice_count;