[FFmpeg-cvslog] png: check bit depth for PAL8/Y400A pixel formats.

[Ronald S. Bultje]

ffmpeg | branch: release/0.8 | Ronald S. Bultje <rsbultje at gmail.com> | Wed May  2 10:58:55 2012 -0700| [269dbc53599e588efc6027df634a9d5b9476c3fc] | committer: Reinhard Tartler

png: check bit depth for PAL8/Y400A pixel formats.

Wrong bit depth can lead to invalid rowsize values, which crashes the
decoder further down.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org
(cherry picked from commit d2205d6543881f2e6fa18c8a354bbcf91a1235f7)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>
(cherry picked from commit b8d6ba9d50e80fdce2ed74cdaffd4960df8a21c5)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=269dbc53599e588efc6027df634a9d5b9476c3fc
---

 libavcodec/pngdec.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 1268c9e..aed3d60 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -488,9 +488,11 @@ static int decode_frame(AVCodecContext *avctx,
                 } else if (s->bit_depth == 1 &&
                            s->color_type == PNG_COLOR_TYPE_GRAY) {
                     avctx->pix_fmt = PIX_FMT_MONOBLACK;
-                } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
+                } else if (s->bit_depth == 8 &&
+                           s->color_type == PNG_COLOR_TYPE_PALETTE) {
                     avctx->pix_fmt = PIX_FMT_PAL8;
-                } else if (s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
+                } else if (s->bit_depth == 8 &&
+                           s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
                     avctx->pix_fmt = PIX_FMT_Y400A;
                 } else {
                     goto fail;