[FFmpeg-cvslog] avcodec/cinepak: Check slice_size before allocating image

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Apr 27 23:37:26 2019 +0200| [b606493717db6424d693e1a944f51171e9e72905] | committer: Michael Niedermayer

avcodec/cinepak: Check slice_size before allocating image

Fixes: Timeout (16sec -> 125msec)
Fixes: 14283/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_CINEPAK_fuzzer-5742851457024000

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Tomas Härdin <tjoppen at acc.umu.se>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b606493717db6424d693e1a944f51171e9e72905
---

 libavcodec/cinepak.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libavcodec/cinepak.c b/libavcodec/cinepak.c
index 9b0077402f..d26c505222 100644
--- a/libavcodec/cinepak.c
+++ b/libavcodec/cinepak.c
@@ -353,6 +353,13 @@ static int cinepak_predecode_check (CinepakContext *s)
     if (s->size < 10 + s->sega_film_skip_bytes + num_strips * 12)
         return AVERROR_INVALIDDATA;
 
+    if (num_strips) {
+        uint8_t *data = s->data + 10 + s->sega_film_skip_bytes;
+        int strip_size = AV_RB24 (data + 1);
+        if (strip_size < 12 || strip_size > encoded_buf_size)
+            return AVERROR_INVALIDDATA;
+    }
+
     return 0;
 }