[FFmpeg-devel] [PATCH 1/3] avcodec/huffyuvdec: avoid undefined behavior with get_vlc2() failure

From: Michael Niedermayer <michael@niedermayer.cc>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: [FFmpeg-devel] [PATCH 1/3] avcodec/huffyuvdec: avoid undefined behavior with get_vlc2() failure
Date: Tue, 20 Jun 2023 01:04:22 +0200
Message-ID: <20230619230424.30270-1-michael@niedermayer.cc> (raw)

Fixes: left shift of negative value -1
Fixes: 59889/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HUFFYUV_fuzzer-5472742275940352

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

diff --git a/libavcodec/huffyuvdec.c b/libavcodec/huffyuvdec.c
index 8ba67bbdeb..1a7690da94 100644
--- a/libavcodec/huffyuvdec.c
+++ b/libavcodec/huffyuvdec.c
@@ -755,7 +755,7 @@ static void decode_plane_bitstream(HYuvDecContext *s, int width, int plane)
             }
         }
         if( width&1 && get_bits_left(&s->gb)>0 ) {
-            int dst = get_vlc2(&s->gb, s->vlc[plane].table, VLC_BITS, 3)<<2;
+            int dst = (unsigned)get_vlc2(&s->gb, s->vlc[plane].table, VLC_BITS, 3)<<2;
             s->temp16[0][width-1] = dst + get_bits(&s->gb, 2);
         }
     }
-- 
2.17.1

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