From 8323e0dc73c3dcb706a84cf57032d4dc4552f670 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 14 Sep 2019 18:31:40 +0200 Subject: [PATCH] avcodec/ituh263dec: Make the condition for the studio slice start code match between ff_h263_resync() and ff_mpeg4_decode_studio_slice_header() If they mismatch an infinite loop can occur Fixes: Timeout (infinite loop) Fixes: 17043/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG4_fuzzer-5695051748868096 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 8335ba8ae99941422bef0e16ea8cf1ebe2e9a7b3) Signed-off-by: Michael Niedermayer --- libavcodec/ituh263dec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/ituh263dec.c b/libavcodec/ituh263dec.c index 1b57e53cad..8bedaac536 100644 --- a/libavcodec/ituh263dec.c +++ b/libavcodec/ituh263dec.c @@ -222,7 +222,7 @@ int ff_h263_resync(MpegEncContext *s){ get_bits(&s->gb, 8); } - if (show_bits_long(&s->gb, 32) == SLICE_START_CODE) + if (get_bits_left(&s->gb) >= 32 && show_bits_long(&s->gb, 32) == SLICE_START_CODE) return get_bits_count(&s->gb); else return -1;