[FFmpeg-cvslog] avcodec/apedec: Fix integer overflows in predictor_update_3930()
Michael Niedermayer
git at videolan.org
Wed Apr 6 22:55:39 EEST 2022
ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Mon Jan 3 19:15:18 2022 +0100| [671850fe550b309f6199e1811c59cc548bd21e8a] | committer: Michael Niedermayer
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 <michael at niedermayer.cc>
(cherry picked from commit 0c9c9bbd01bd82c35b6a908592d9dd6d9f4bd4a0)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=671850fe550b309f6199e1811c59cc548bd21e8a
---
libavcodec/apedec.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
index 621db062e6..43d7110c57 100644
--- a/libavcodec/apedec.c
+++ b/libavcodec/apedec.c
@@ -1061,13 +1061,13 @@ 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] +
@@ -1078,10 +1078,10 @@ 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];
}
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