[FFmpeg-devel] [PATCH 2/2] avcodec/mobiclip: Avoid undefined integer overflow in MV computation

Michael Niedermayer michael at niedermayer.cc
Tue Mar 2 20:52:31 EET 2021


Fixes: signed integer overflow: 1 + 2147483647 cannot be represented in type 'int'
Fixes: 30877/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MOBICLIP_fuzzer-4775601145774080

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/mobiclip.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/mobiclip.c b/libavcodec/mobiclip.c
index e5c6617325..9392ab947e 100644
--- a/libavcodec/mobiclip.c
+++ b/libavcodec/mobiclip.c
@@ -1091,8 +1091,8 @@ static int predict_motion(AVCodecContext *avctx,
             sidx += 6;
 
         if (index > 0) {
-            mv.x = mv.x + get_se_golomb(gb);
-            mv.y = mv.y + get_se_golomb(gb);
+            mv.x = mv.x + (unsigned)get_se_golomb(gb);
+            mv.y = mv.y + (unsigned)get_se_golomb(gb);
         }
         if (mv.x >= INT_MAX || mv.y >= INT_MAX)
             return AVERROR_INVALIDDATA;
-- 
2.17.1



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