From 6ca82975b7a8eaf676a52738ec8e7e36732327cc Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 27 Apr 2017 02:27:16 +0200 Subject: [PATCH] avcodec/mdec: Fix runtime error: left shift of negative value -127 Fixes undefined behavior Fixes: 1275/clusterfuzz-testcase-minimized-6718162017976320 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/mdec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/mdec.c b/libavcodec/mdec.c index 1cc4ca4742..42bd561cd7 100644 --- a/libavcodec/mdec.c +++ b/libavcodec/mdec.c @@ -73,7 +73,7 @@ static inline int mdec_decode_block_intra(MDECContext *a, int16_t *block, int n) if (diff >= 0xffff) return AVERROR_INVALIDDATA; a->last_dc[component] += diff; - block[0] = a->last_dc[component] << 3; + block[0] = a->last_dc[component] * (1 << 3); } i = 0;