avcodec/pngdec: Check IHDR/IDAT order

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@gmx.at>
[sunweaver] - Port this commit to libav in Debian jessie.

Gbp-Pq: Name CVE-2014-9317.patch

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 2790bf432b9014c940babb7178dfabb5fb526bcb..58b57997ed6e92c55318d98640940ae2dda3529d 100644 (file)
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -445,6 +445,12 @@ static int decode_frame(AVCodecContext *avctx,
         case MKTAG('I', 'H', 'D', 'R'):
             if (length != 13)
                 goto fail;
+
+            if (s->state & PNG_IDAT) {
+                av_log(avctx, AV_LOG_ERROR, "IHDR after IDAT\n");
+                goto fail;
+            }
+
             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)) {