From 20ade59d9633def4ebf84ec170f56367bfb6aa6c Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 9 Apr 2020 15:37:55 +0200 Subject: [PATCH] avcodec/dpcm: clip exponent into supported range in XAN DPCM Fixes: shift exponent 32 is too large for 32-bit type 'int' Fixes: 21200/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_XAN_DPCM_fuzzer-5754704894361600 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Reviewed-by: Anton Khirnov Signed-off-by: Michael Niedermayer --- libavcodec/dpcm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/libavcodec/dpcm.c b/libavcodec/dpcm.c index 069bf1dcd8..7078419f08 100644 --- a/libavcodec/dpcm.c +++ b/libavcodec/dpcm.c @@ -321,9 +321,8 @@ static int dpcm_decode_frame(AVCodecContext *avctx, void *data, shift[ch] -= (2 * n); diff = sign_extend((diff &~ 3) << 8, 16); - /* saturate the shifter to a lower limit of 0 */ - if (shift[ch] < 0) - shift[ch] = 0; + /* saturate the shifter to 0..31 */ + shift[ch] = av_clip_uintp2(shift[ch], 5); diff >>= shift[ch]; predictor[ch] += diff;