[FFmpeg-cvslog] avcodec/pngdec: Only allow one IHDR chunk

[Michael Niedermayer]

ffmpeg | branch: release/2.6 | Michael Niedermayer <michaelni at gmx.at> | Mon Jun 29 21:08:05 2015 +0200| [63ef4014c5ff13953025af861976f79c85cf373f] | committer: Michael Niedermayer

avcodec/pngdec: Only allow one IHDR chunk

Multiple IHDR chunks are forbidden in PNG
Fixes inconsistency and out of array accesses

Fixes: asan_heap-oob_4d5c5a_1738_cov_2638287726_c-m2-8f2b481b7fd9bd745e620b7c01a18df2.png

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit 47f4e2d8960ca756ca153ab8e3e93d80449b8c91)

Conflicts:

	libavcodec/pngdec.c

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=63ef4014c5ff13953025af861976f79c85cf373f
---

 libavcodec/pngdec.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 7200442..5a2c9c2 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -539,6 +539,11 @@ static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
         return AVERROR_INVALIDDATA;
     }
 
+    if (s->state & PNG_IHDR) {
+        av_log(avctx, AV_LOG_ERROR, "Multiple IHDR\n");
+        return AVERROR_INVALIDDATA;
+    }
+
     s->width  = s->cur_w = bytestream2_get_be32(&s->gb);
     s->height = s->cur_h = bytestream2_get_be32(&s->gb);
     if (av_image_check_size(s->width, s->height, 0, avctx)) {