| Message ID | 20190903001426.8957-5-michael@niedermayer.cc |
|---|---|
| State | New |
| Headers | show |
On 9/2/2019 9:14 PM, Michael Niedermayer wrote: > Fixes: OOM > Fixes: 16627/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5638059583864832 > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > --- > libavcodec/apedec.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c > index e218f7c043..774ce18531 100644 > --- a/libavcodec/apedec.c > +++ b/libavcodec/apedec.c > @@ -1475,6 +1475,9 @@ static int ape_decode_frame(AVCodecContext *avctx, void *data, > return AVERROR_INVALIDDATA; > } > > + if (nblocks * (int64_t)avctx->channels > avctx->max_samples) > + return AVERROR(EINVAL); > + Shouldn't this be checked in ff_get_buffer()? Same as max_pixels, but checking "frame->nb_samples > avctx->max_samples" instead or width/height. Otherwise it will barely be used. > /* Initialize the frame decoder */ > if (init_frame_decoder(s) < 0) { > av_log(avctx, AV_LOG_ERROR, "Error reading frame header\n"); >
On Mon, Sep 02, 2019 at 09:40:47PM -0300, James Almer wrote: > On 9/2/2019 9:14 PM, Michael Niedermayer wrote: > > Fixes: OOM > > Fixes: 16627/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5638059583864832 > > > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > --- > > libavcodec/apedec.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c > > index e218f7c043..774ce18531 100644 > > --- a/libavcodec/apedec.c > > +++ b/libavcodec/apedec.c > > @@ -1475,6 +1475,9 @@ static int ape_decode_frame(AVCodecContext *avctx, void *data, > > return AVERROR_INVALIDDATA; > > } > > > > + if (nblocks * (int64_t)avctx->channels > avctx->max_samples) > > + return AVERROR(EINVAL); > > + > > Shouldn't this be checked in ff_get_buffer()? Same as max_pixels, but > checking "frame->nb_samples > avctx->max_samples" instead or > width/height. Otherwise it will barely be used. you are correct, it should be checked in *get_buffer somewhere too. But the offending allocation occurs before any *get_buffer calls so this check here is what is neccessary and sufficient for this specific bug Thanks [...]
On 9/3/2019 8:13 AM, Michael Niedermayer wrote: > On Mon, Sep 02, 2019 at 09:40:47PM -0300, James Almer wrote: >> On 9/2/2019 9:14 PM, Michael Niedermayer wrote: >>> Fixes: OOM >>> Fixes: 16627/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5638059583864832 >>> >>> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg >>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> >>> --- >>> libavcodec/apedec.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c >>> index e218f7c043..774ce18531 100644 >>> --- a/libavcodec/apedec.c >>> +++ b/libavcodec/apedec.c >>> @@ -1475,6 +1475,9 @@ static int ape_decode_frame(AVCodecContext *avctx, void *data, >>> return AVERROR_INVALIDDATA; >>> } >>> >>> + if (nblocks * (int64_t)avctx->channels > avctx->max_samples) >>> + return AVERROR(EINVAL); >>> + >> >> Shouldn't this be checked in ff_get_buffer()? Same as max_pixels, but >> checking "frame->nb_samples > avctx->max_samples" instead or >> width/height. Otherwise it will barely be used. > > you are correct, it should be checked in *get_buffer somewhere too. > But the offending allocation occurs before any *get_buffer calls so > this check here is what is neccessary and sufficient for this specific > bug If the allocation you're talking about is https://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/apedec.c;h=490b11b94e0b1666f18248b2b247c874fed6e0bc;hb=HEAD#l1500 then you could just move it (and the five lines that follow it) right below the ff_get_buffer() call. But it should be ok either way. > > Thanks > > [...] > > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe". >
On Tue, Sep 03, 2019 at 02:39:27PM -0300, James Almer wrote: > On 9/3/2019 8:13 AM, Michael Niedermayer wrote: > > On Mon, Sep 02, 2019 at 09:40:47PM -0300, James Almer wrote: > >> On 9/2/2019 9:14 PM, Michael Niedermayer wrote: > >>> Fixes: OOM > >>> Fixes: 16627/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5638059583864832 > >>> > >>> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > >>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > >>> --- > >>> libavcodec/apedec.c | 3 +++ > >>> 1 file changed, 3 insertions(+) > >>> > >>> diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c > >>> index e218f7c043..774ce18531 100644 > >>> --- a/libavcodec/apedec.c > >>> +++ b/libavcodec/apedec.c > >>> @@ -1475,6 +1475,9 @@ static int ape_decode_frame(AVCodecContext *avctx, void *data, > >>> return AVERROR_INVALIDDATA; > >>> } > >>> > >>> + if (nblocks * (int64_t)avctx->channels > avctx->max_samples) > >>> + return AVERROR(EINVAL); > >>> + > >> > >> Shouldn't this be checked in ff_get_buffer()? Same as max_pixels, but > >> checking "frame->nb_samples > avctx->max_samples" instead or > >> width/height. Otherwise it will barely be used. > > > > you are correct, it should be checked in *get_buffer somewhere too. > > But the offending allocation occurs before any *get_buffer calls so > > this check here is what is neccessary and sufficient for this specific > > bug > > If the allocation you're talking about is > https://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/apedec.c;h=490b11b94e0b1666f18248b2b247c874fed6e0bc;hb=HEAD#l1500 > then you could just move it (and the five lines that follow it) right > below the ff_get_buffer() call. ill apply a patch which does the check in ff_get_buffer() at the same point where its done for max_pixels thx [...]
On Tue, Sep 03, 2019 at 02:39:27PM -0300, James Almer wrote: > On 9/3/2019 8:13 AM, Michael Niedermayer wrote: > > On Mon, Sep 02, 2019 at 09:40:47PM -0300, James Almer wrote: > >> On 9/2/2019 9:14 PM, Michael Niedermayer wrote: > >>> Fixes: OOM > >>> Fixes: 16627/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5638059583864832 > >>> > >>> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > >>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > >>> --- > >>> libavcodec/apedec.c | 3 +++ > >>> 1 file changed, 3 insertions(+) > >>> > >>> diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c > >>> index e218f7c043..774ce18531 100644 > >>> --- a/libavcodec/apedec.c > >>> +++ b/libavcodec/apedec.c > >>> @@ -1475,6 +1475,9 @@ static int ape_decode_frame(AVCodecContext *avctx, void *data, > >>> return AVERROR_INVALIDDATA; > >>> } > >>> > >>> + if (nblocks * (int64_t)avctx->channels > avctx->max_samples) > >>> + return AVERROR(EINVAL); > >>> + > >> > >> Shouldn't this be checked in ff_get_buffer()? Same as max_pixels, but > >> checking "frame->nb_samples > avctx->max_samples" instead or > >> width/height. Otherwise it will barely be used. > > > > you are correct, it should be checked in *get_buffer somewhere too. > > But the offending allocation occurs before any *get_buffer calls so > > this check here is what is neccessary and sufficient for this specific > > bug > > If the allocation you're talking about is > https://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/apedec.c;h=490b11b94e0b1666f18248b2b247c874fed6e0bc;hb=HEAD#l1500 > then you could just move it (and the five lines that follow it) right > below the ff_get_buffer() call. will apply with these changes and some more to reset the incorrect samples in case of ff_get_buffer failure thx [...]
diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c index e218f7c043..774ce18531 100644 --- a/libavcodec/apedec.c +++ b/libavcodec/apedec.c @@ -1475,6 +1475,9 @@ static int ape_decode_frame(AVCodecContext *avctx, void *data, return AVERROR_INVALIDDATA; } + if (nblocks * (int64_t)avctx->channels > avctx->max_samples) + return AVERROR(EINVAL); + /* Initialize the frame decoder */ if (init_frame_decoder(s) < 0) { av_log(avctx, AV_LOG_ERROR, "Error reading frame header\n");
Fixes: OOM Fixes: 16627/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5638059583864832 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavcodec/apedec.c | 3 +++ 1 file changed, 3 insertions(+)