[FFmpeg-cvslog] webp: fix infinite loop in webp_decode_frame

[Andreas Cadhalpun]

ffmpeg | branch: release/2.7 | Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> | Thu Jul  2 23:45:46 2015 +0200| [762a5878a6b0bef923ef97c15fdb8274a0351278] | committer: Andreas Cadhalpun

webp: fix infinite loop in webp_decode_frame

The loop always needs at least 8 bytes for chunk_type and chunk_size.
If fewer are left, bytestream2_get_le32 just returns 0 without
reading any bytes, leading to an infinite loop.

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit 0762152f7af6cd93bc8f504d5503723500c3f369)
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=762a5878a6b0bef923ef97c15fdb8274a0351278
---

 libavcodec/webp.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/webp.c b/libavcodec/webp.c
index 47e9e9e..723a847 100644
--- a/libavcodec/webp.c
+++ b/libavcodec/webp.c
@@ -1387,7 +1387,7 @@ static int webp_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
     }
 
     av_dict_free(&s->exif_metadata);
-    while (bytestream2_get_bytes_left(&gb) > 0) {
+    while (bytestream2_get_bytes_left(&gb) > 8) {
         char chunk_str[5] = { 0 };
 
         chunk_type = bytestream2_get_le32(&gb);