| Message ID | 20170310142452.22210-1-michael@niedermayer.cc |
|---|---|
| State | Accepted |
| Commit | ce010655a6b82d49bd8df179d73bcb5802a273c1 |
| Headers | show |
On Fri, 10 Mar 2017 15:24:51 +0100 Michael Niedermayer <michael@niedermayer.cc> wrote: > Fixes: 732/clusterfuzz-testcase-4872990070145024 > > See: [FFmpeg-devel] [PATCH 2/6] avcodec/dca_xll: Fix runtime error: signed integer overflow: 2147286116 + 6298923 cannot be represented in type 'int' > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > --- > libavcodec/dca_xll.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/libavcodec/dca_xll.c b/libavcodec/dca_xll.c > index 6cebda35e4..0fe90c7348 100644 > --- a/libavcodec/dca_xll.c > +++ b/libavcodec/dca_xll.c > @@ -1312,7 +1312,7 @@ static int combine_residual_frame(DCAXllDecoder *s, DCAXllChSet *c) > } else { > // No downmix scaling > for (n = 0; n < nsamples; n++) > - dst[n] += (src[n] + round) >> shift; > + dst[n] += (unsigned)((src[n] + round) >> shift); > } > } > Seems reasonable.
On Fri, Mar 10, 2017 at 3:24 PM, Michael Niedermayer <michael@niedermayer.cc> wrote: > Fixes: 732/clusterfuzz-testcase-4872990070145024 > > See: [FFmpeg-devel] [PATCH 2/6] avcodec/dca_xll: Fix runtime error: signed integer overflow: 2147286116 + 6298923 cannot be represented in type 'int' > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > --- > libavcodec/dca_xll.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/libavcodec/dca_xll.c b/libavcodec/dca_xll.c > index 6cebda35e4..0fe90c7348 100644 > --- a/libavcodec/dca_xll.c > +++ b/libavcodec/dca_xll.c > @@ -1312,7 +1312,7 @@ static int combine_residual_frame(DCAXllDecoder *s, DCAXllChSet *c) > } else { > // No downmix scaling > for (n = 0; n < nsamples; n++) > - dst[n] += (src[n] + round) >> shift; > + dst[n] += (unsigned)((src[n] + round) >> shift); > } > } > audio samples are typically signed, using negative values too, is this really safe to just cast it like that, without modifying the value in the end? - Hendrik
On Fri, Mar 10, 2017 at 06:50:34PM +0100, Hendrik Leppkes wrote: > On Fri, Mar 10, 2017 at 3:24 PM, Michael Niedermayer > <michael@niedermayer.cc> wrote: > > Fixes: 732/clusterfuzz-testcase-4872990070145024 > > > > See: [FFmpeg-devel] [PATCH 2/6] avcodec/dca_xll: Fix runtime error: signed integer overflow: 2147286116 + 6298923 cannot be represented in type 'int' > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > --- > > libavcodec/dca_xll.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/libavcodec/dca_xll.c b/libavcodec/dca_xll.c > > index 6cebda35e4..0fe90c7348 100644 > > --- a/libavcodec/dca_xll.c > > +++ b/libavcodec/dca_xll.c > > @@ -1312,7 +1312,7 @@ static int combine_residual_frame(DCAXllDecoder *s, DCAXllChSet *c) > > } else { > > // No downmix scaling > > for (n = 0; n < nsamples; n++) > > - dst[n] += (src[n] + round) >> shift; > > + dst[n] += (unsigned)((src[n] + round) >> shift); > > } > > } > > > > audio samples are typically signed, using negative values too, is this > really safe to just cast it like that, without modifying the value in > the end? signed and unsigned operations for +,-,*,<< are identical on twos complement with in and output data types matching and twos complement (strictly speaking in the signed case some are undefined in C ...) [...]
On Fri, Mar 10, 2017 at 03:52:06PM +0100, wm4 wrote: > On Fri, 10 Mar 2017 15:24:51 +0100 > Michael Niedermayer <michael@niedermayer.cc> wrote: > > > Fixes: 732/clusterfuzz-testcase-4872990070145024 > > > > See: [FFmpeg-devel] [PATCH 2/6] avcodec/dca_xll: Fix runtime error: signed integer overflow: 2147286116 + 6298923 cannot be represented in type 'int' > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > --- > > libavcodec/dca_xll.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/libavcodec/dca_xll.c b/libavcodec/dca_xll.c > > index 6cebda35e4..0fe90c7348 100644 > > --- a/libavcodec/dca_xll.c > > +++ b/libavcodec/dca_xll.c > > @@ -1312,7 +1312,7 @@ static int combine_residual_frame(DCAXllDecoder *s, DCAXllChSet *c) > > } else { > > // No downmix scaling > > for (n = 0; n < nsamples; n++) > > - dst[n] += (src[n] + round) >> shift; > > + dst[n] += (unsigned)((src[n] + round) >> shift); > > } > > } > > > > Seems reasonable. applied thx
diff --git a/libavcodec/dca_xll.c b/libavcodec/dca_xll.c index 6cebda35e4..0fe90c7348 100644 --- a/libavcodec/dca_xll.c +++ b/libavcodec/dca_xll.c @@ -1312,7 +1312,7 @@ static int combine_residual_frame(DCAXllDecoder *s, DCAXllChSet *c) } else { // No downmix scaling for (n = 0; n < nsamples; n++) - dst[n] += (src[n] + round) >> shift; + dst[n] += (unsigned)((src[n] + round) >> shift); } }
Fixes: 732/clusterfuzz-testcase-4872990070145024 See: [FFmpeg-devel] [PATCH 2/6] avcodec/dca_xll: Fix runtime error: signed integer overflow: 2147286116 + 6298923 cannot be represented in type 'int' Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavcodec/dca_xll.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)