[FFmpeg-cvslog] avcodec/ac3_parser: Check init_get_bits8() for failure

[Michael Niedermayer]

ffmpeg | branch: release/4.0 | Michael Niedermayer <michael at niedermayer.cc> | Wed Jun 27 16:59:13 2018 +0200| [0003ace83b18f68c981c8ad401bee75315edf9f5] | committer: Michael Niedermayer

avcodec/ac3_parser: Check init_get_bits8() for failure

Fixes: null pointer dereference
Fixes: ffmpeg_crash_6.avi

Found-by: Thuan Pham, Marcel Böhme, Andrew Santosa and Alexandru Razvan Caciulescu with AFLSmart
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 00e8181bd97c834fe60751b0c511d4bb97875f78)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0003ace83b18f68c981c8ad401bee75315edf9f5
---

 libavcodec/ac3_parser.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavcodec/ac3_parser.c b/libavcodec/ac3_parser.c
index f4618bf215..1e203ae6ac 100644
--- a/libavcodec/ac3_parser.c
+++ b/libavcodec/ac3_parser.c
@@ -162,7 +162,9 @@ int avpriv_ac3_parse_header(AC3HeaderInfo **phdr, const uint8_t *buf,
         return AVERROR(ENOMEM);
     hdr = *phdr;
 
-    init_get_bits8(&gb, buf, size);
+    err = init_get_bits8(&gb, buf, size);
+    if (err < 0)
+        return AVERROR_INVALIDDATA;
     err = ff_ac3_parse_header(&gb, hdr);
     if (err < 0)
         return AVERROR_INVALIDDATA;