From 9a1fa28965b04cd875cc9d54f537c5617fb0e414 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Mon, 3 Jan 2022 19:15:18 +0100 Subject: [PATCH] avcodec/apedec: Fix integer overflows in predictor_update_3930() Fixes: signed integer overflow: 1074134419 - -1075212485 cannot be represented in type 'int' Fixes: 43273/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-4706880883130368 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 0c9c9bbd01bd82c35b6a908592d9dd6d9f4bd4a0) Signed-off-by: Michael Niedermayer --- libavcodec/apedec.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c index 2a549c8fe4..431b2f9ad3 100644 --- a/libavcodec/apedec.c +++ b/libavcodec/apedec.c @@ -1038,13 +1038,13 @@ static av_always_inline int predictor_update_3930(APEPredictor *p, const int delayA) { int32_t predictionA, sign; - int32_t d0, d1, d2, d3; + uint32_t d0, d1, d2, d3; p->buf[delayA] = p->lastA[filter]; d0 = p->buf[delayA ]; - d1 = p->buf[delayA ] - p->buf[delayA - 1]; - d2 = p->buf[delayA - 1] - p->buf[delayA - 2]; - d3 = p->buf[delayA - 2] - p->buf[delayA - 3]; + d1 = p->buf[delayA ] - (unsigned)p->buf[delayA - 1]; + d2 = p->buf[delayA - 1] - (unsigned)p->buf[delayA - 2]; + d3 = p->buf[delayA - 2] - (unsigned)p->buf[delayA - 3]; predictionA = d0 * p->coeffsA[filter][0] + d1 * p->coeffsA[filter][1] + @@ -1055,10 +1055,10 @@ static av_always_inline int predictor_update_3930(APEPredictor *p, p->filterA[filter] = p->lastA[filter] + ((int)(p->filterA[filter] * 31U) >> 5); sign = APESIGN(decoded); - p->coeffsA[filter][0] += ((d0 < 0) * 2 - 1) * sign; - p->coeffsA[filter][1] += ((d1 < 0) * 2 - 1) * sign; - p->coeffsA[filter][2] += ((d2 < 0) * 2 - 1) * sign; - p->coeffsA[filter][3] += ((d3 < 0) * 2 - 1) * sign; + p->coeffsA[filter][0] += (((int32_t)d0 < 0) * 2 - 1) * sign; + p->coeffsA[filter][1] += (((int32_t)d1 < 0) * 2 - 1) * sign; + p->coeffsA[filter][2] += (((int32_t)d2 < 0) * 2 - 1) * sign; + p->coeffsA[filter][3] += (((int32_t)d3 < 0) * 2 - 1) * sign; return p->filterA[filter]; }