| Message ID | 20240426235211.3718252-1-michael@niedermayer.cc |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel,1/5] avcodec/pngdec: Check last AVFrame before deref | expand |
| Context | Check | Description |
|---|---|---|
| yinshiyou/make_loongarch64 | success | Make finished |
| yinshiyou/make_fate_loongarch64 | success | Make fate finished |
Michael Niedermayer: > Fixes: NULL pointer dereference > Fixes: 68184/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APNG_fuzzer-4926478069334016 > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > --- > libavcodec/pngdec.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c > index f7751223b81..b24bfa248dc 100644 > --- a/libavcodec/pngdec.c > +++ b/libavcodec/pngdec.c > @@ -1218,7 +1218,7 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s, > return AVERROR_INVALIDDATA; > } > > - if ((sequence_number == 0 || !s->last_picture.f->data[0]) && > + if ((sequence_number == 0 || !s->last_picture.f || !s->last_picture.f->data[0]) && > dispose_op == APNG_DISPOSE_OP_PREVIOUS) { > // No previous frame to revert to for the first frame > // Spec says to just treat it as a APNG_DISPOSE_OP_BACKGROUND Just checking for !s->last_picture.f is enough -- s->last_picture.f is set if and only if s->last_picture.f->data[0] is set. - Andreas
On Sat, Apr 27, 2024 at 11:36:30AM +0200, Andreas Rheinhardt wrote: > Michael Niedermayer: > > Fixes: NULL pointer dereference > > Fixes: 68184/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APNG_fuzzer-4926478069334016 > > > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > --- > > libavcodec/pngdec.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c > > index f7751223b81..b24bfa248dc 100644 > > --- a/libavcodec/pngdec.c > > +++ b/libavcodec/pngdec.c > > @@ -1218,7 +1218,7 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s, > > return AVERROR_INVALIDDATA; > > } > > > > - if ((sequence_number == 0 || !s->last_picture.f->data[0]) && > > + if ((sequence_number == 0 || !s->last_picture.f || !s->last_picture.f->data[0]) && > > dispose_op == APNG_DISPOSE_OP_PREVIOUS) { > > // No previous frame to revert to for the first frame > > // Spec says to just treat it as a APNG_DISPOSE_OP_BACKGROUND > > Just checking for !s->last_picture.f is enough -- s->last_picture.f is > set if and only if s->last_picture.f->data[0] is set. ok will apply with that simplified thx [...]
diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c index f7751223b81..b24bfa248dc 100644 --- a/libavcodec/pngdec.c +++ b/libavcodec/pngdec.c @@ -1218,7 +1218,7 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s, return AVERROR_INVALIDDATA; } - if ((sequence_number == 0 || !s->last_picture.f->data[0]) && + if ((sequence_number == 0 || !s->last_picture.f || !s->last_picture.f->data[0]) && dispose_op == APNG_DISPOSE_OP_PREVIOUS) { // No previous frame to revert to for the first frame // Spec says to just treat it as a APNG_DISPOSE_OP_BACKGROUND
Fixes: NULL pointer dereference Fixes: 68184/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APNG_fuzzer-4926478069334016 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavcodec/pngdec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)