[FFmpeg-cvslog] avcodec/anm: Check extradata length before allocating frame

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Sat May 30 05:25:06 2020 +0200| [45c350226696be9deae7c73d67fdc93f848f9a91] | committer: Andreas Rheinhardt

avcodec/anm: Check extradata length before allocating frame

Then one doesn't need to free the frame in case the length turns out to
be insufficient.

Reviewed-by: Peter Ross <pross at xvid.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=45c350226696be9deae7c73d67fdc93f848f9a91
---

 libavcodec/anm.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/libavcodec/anm.c b/libavcodec/anm.c
index cd1fcc5998..e9b19d880d 100644
--- a/libavcodec/anm.c
+++ b/libavcodec/anm.c
@@ -40,6 +40,9 @@ static av_cold int decode_init(AVCodecContext *avctx)
     AnmContext *s = avctx->priv_data;
     int i;
 
+    if (avctx->extradata_size < 16 * 8 + 4 * 256)
+        return AVERROR_INVALIDDATA;
+
     avctx->pix_fmt = AV_PIX_FMT_PAL8;
 
     s->frame = av_frame_alloc();
@@ -47,11 +50,6 @@ static av_cold int decode_init(AVCodecContext *avctx)
         return AVERROR(ENOMEM);
 
     bytestream2_init(&s->gb, avctx->extradata, avctx->extradata_size);
-    if (bytestream2_get_bytes_left(&s->gb) < 16 * 8 + 4 * 256) {
-        av_frame_free(&s->frame);
-        return AVERROR_INVALIDDATA;
-    }
-
     bytestream2_skipu(&s->gb, 16 * 8);
     for (i = 0; i < 256; i++)
         s->palette[i] = (0xFFU << 24) | bytestream2_get_le32u(&s->gb);