[FFmpeg-cvslog] avcodec/wbmpdec: use remaining size not whole size

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu Jan 12 21:23:21 2023 +0100| [1ab0f83b0a243c635d77f8b116646bb7594988d4] | committer: Michael Niedermayer

avcodec/wbmpdec: use remaining size not whole size

Fixes: out of array access
Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WBMP_fuzzer-6652634692190208
Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WBMP_fuzzer-6653703453278208
Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WBMP_fuzzer-6668020758216704
Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WBMP_fuzzer-6684749875249152

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Peter Ross <pross at xvid.org>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1ab0f83b0a243c635d77f8b116646bb7594988d4
---

 libavcodec/wbmpdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/wbmpdec.c b/libavcodec/wbmpdec.c
index 9638b55b94..8b105bc135 100644
--- a/libavcodec/wbmpdec.c
+++ b/libavcodec/wbmpdec.c
@@ -72,7 +72,7 @@ static int wbmp_decode_frame(AVCodecContext *avctx, AVFrame *p,
     if (p->linesize[0] == (width + 7) / 8)
         bytestream2_get_buffer(&gb, p->data[0], height * ((width + 7) / 8));
     else
-        readbits(p->data[0], width, height, p->linesize[0], gb.buffer, gb.buffer_end - gb.buffer_start);
+        readbits(p->data[0], width, height, p->linesize[0], gb.buffer, gb.buffer_end - gb.buffer);
 
     p->key_frame = 1;
     p->pict_type = AV_PICTURE_TYPE_I;