[FFmpeg-cvslog] avcodec/ac3dec: Use frame_size if superframe_size is 0

[Michael Niedermayer]

ffmpeg | branch: release/4.0 | Michael Niedermayer <michael at niedermayer.cc> | Fri May 18 01:48:38 2018 +0200| [217367b5eb0a6be8e1c5c819ef2a407d30591091] | committer: Michael Niedermayer

avcodec/ac3dec: Use frame_size if superframe_size is 0

Fixes: Infinite loop
Fixes: 7669/clusterfuzz-testcase-ffmpeg_AV_CODEC_ID_AC3_FIXED_fuzzer-4689042185650176
Fixes: 7670/clusterfuzz-testcase-ffmpeg_AV_CODEC_ID_AC3_fuzzer-4706306762997760
Fixes: 7672/clusterfuzz-testcase-ffmpeg_AV_CODEC_ID_EAC3_fuzzer-4702108499574784

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit f77eee67e25b13e32e899efb6fdf01719914353e)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=217367b5eb0a6be8e1c5c819ef2a407d30591091
---

 libavcodec/ac3dec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
index b14d2e74ac..1d3180b935 100644
--- a/libavcodec/ac3dec.c
+++ b/libavcodec/ac3dec.c
@@ -1800,6 +1800,9 @@ dependent_frame:
 
     *got_frame_ptr = 1;
 
+    if (!s->superframe_size)
+        return FFMIN(full_buf_size, s->frame_size);
+
     return FFMIN(full_buf_size, s->superframe_size);
 }