[FFmpeg-cvslog] avcodec/loco: Limit lossy parameter so it is sane and does not overflow

[Michael Niedermayer]

ffmpeg | branch: release/4.1 | Michael Niedermayer <michael at niedermayer.cc> | Sat Jun 15 21:47:16 2019 +0200| [479b70d2f84b340a66ade598454df968bf71cf5f] | committer: Michael Niedermayer

avcodec/loco: Limit lossy parameter so it is sane and does not overflow

Fixes: 15248/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_LOCO_fuzzer-5087440458481664
Fixes: signed integer overflow: 3 + 2147483647 cannot be represented in type 'int'

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 ce3b0b9066b433564ed3ee3eed3a1e8f2c0834a1)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=479b70d2f84b340a66ade598454df968bf71cf5f
---

 libavcodec/loco.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/loco.c b/libavcodec/loco.c
index 741db3bdce..e8c62b8178 100644
--- a/libavcodec/loco.c
+++ b/libavcodec/loco.c
@@ -295,6 +295,11 @@ static av_cold int decode_init(AVCodecContext *avctx)
         avpriv_request_sample(avctx, "LOCO codec version %i", version);
     }
 
+    if (l->lossy > 65536U) {
+        av_log(avctx, AV_LOG_ERROR, "lossy %i is too large\n", l->lossy);
+        return AVERROR_INVALIDDATA;
+    }
+
     l->mode = AV_RL32(avctx->extradata + 4);
     switch (l->mode) {
     case LOCO_CYUY2: