[FFmpeg-cvslog] avcodec/pngdec: Check IHDR/IDAT order

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Wed Nov 26 15:45:47 2014 +0100| [79ceaf827be0b070675d4cd0a55c3386542defd8] | committer: Michael Niedermayer

avcodec/pngdec: Check IHDR/IDAT order

Fixes out of array access
Fixes: asan_heap-oob_20a6c26_2690_cov_3434532168_mail.png
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=79ceaf827be0b070675d4cd0a55c3386542defd8
---

 libavcodec/pngdec.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index ee6a2ba..f80a3fe 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -524,6 +524,12 @@ static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
 {
     if (length != 13)
         return AVERROR_INVALIDDATA;
+
+    if (s->state & PNG_IDAT) {
+        av_log(avctx, AV_LOG_ERROR, "IHDR after IDAT\n");
+        return AVERROR_INVALIDDATA;
+    }
+
     s->width  = bytestream2_get_be32(&s->gb);
     s->height = bytestream2_get_be32(&s->gb);
     if (av_image_check_size(s->width, s->height, 0, avctx)) {