[FFmpeg-cvslog] avcodec/webp: add assert to ensure palette is not larger than 256

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sun Oct  5 13:00:40 2014 +0200| [436206c1756ce10a5f1cab45ac1d8a974c352e5a] | committer: Michael Niedermayer

avcodec/webp: add assert to ensure palette is not larger than 256

it should not be possible to be larger as its stored as 8bit value
but we would be overwriting a stack buffer if it is ...

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=436206c1756ce10a5f1cab45ac1d8a974c352e5a
---

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

diff --git a/libavcodec/webp.c b/libavcodec/webp.c
index 92becb6..4b1c8e7 100644
--- a/libavcodec/webp.c
+++ b/libavcodec/webp.c
@@ -1065,6 +1065,7 @@ static int apply_color_indexing_transform(WebPContext *s)
     if (img->frame->height * img->frame->width > 300) {
         uint8_t palette[256 * 4];
         const int size = pal->frame->width * 4;
+        av_assert0(size <= 1024U);
         memcpy(palette, GET_PIXEL(pal->frame, 0, 0), size);   // copy palette
         // set extra entries to transparent black
         memset(palette + size, 0, 256 * 4 - size);