[FFmpeg-devel] [PATCH] avcodec/cbs_av1: Use unsigned to avoid undefined shift

Andreas Rheinhardt andreas.rheinhardt at gmail.com
Thu Jun 18 15:41:22 EEST 2020


Fixes: assertion failure
Fixes: left shift of 1 by 31 places cannot be represented in type 'int'
Fixes: 23264/clusterfuzz-testcase-minimized-ffmpeg_BSF_AV1_METADATA_fuzzer-6308429248593920

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
 libavcodec/cbs_av1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/cbs_av1.c b/libavcodec/cbs_av1.c
index 29b316e011..7af63e2165 100644
--- a/libavcodec/cbs_av1.c
+++ b/libavcodec/cbs_av1.c
@@ -125,7 +125,7 @@ static int cbs_av1_write_uvlc(CodedBitstreamContext *ctx, PutBitContext *pbc,
         put_bits(pbc, 1, 1);
     } else {
         zeroes = av_log2(value + 1);
-        v = value - (1 << zeroes) + 1;
+        v = value - (1U << zeroes) + 1;
         put_bits(pbc, zeroes + 1, 1);
         put_bits(pbc, zeroes, v);
     }
-- 
2.20.1



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