| Message ID | 20200531135020.5675-3-michael@niedermayer.cc |
|---|---|
| State | Accepted |
| Commit | 5bd5c3108786bf69f108c55c375f1956f67ca7a4 |
| Headers | show |
| Series | [FFmpeg-devel,1/4] avcodec/jpeg2000dec: clear pointer which become stale in get_ppt() | expand |
| Context | Check | Description |
|---|---|---|
| andriy/default | pending | |
| andriy/make | success | Make finished |
| andriy/make_fate | success | Make fate finished |
On 5/31/2020 10:50 AM, Michael Niedermayer wrote: > Fixes: NULL pointer dereference > Fixes: 22604/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5667739074297856.fuzz > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > --- > libavformat/mlvdec.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/libavformat/mlvdec.c b/libavformat/mlvdec.c > index dae13cae53..03aed71024 100644 > --- a/libavformat/mlvdec.c > +++ b/libavformat/mlvdec.c > @@ -393,10 +393,14 @@ static int read_packet(AVFormatContext *avctx, AVPacket *pkt) > { > MlvContext *mlv = avctx->priv_data; > AVIOContext *pb; > - AVStream *st = avctx->streams[mlv->stream_index]; > + AVStream *st; > int index, ret; > unsigned int size, space; > > + if (!avctx->nb_streams) > + return AVERROR_EOF; Shouldn't you abort during read_header() instead if no streams are ever allocated? > + > + st = avctx->streams[mlv->stream_index]; > if (mlv->pts >= st->duration) > return AVERROR_EOF; > >
On Sun, May 31, 2020 at 10:58:16AM -0300, James Almer wrote: > On 5/31/2020 10:50 AM, Michael Niedermayer wrote: > > Fixes: NULL pointer dereference > > Fixes: 22604/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5667739074297856.fuzz > > > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > --- > > libavformat/mlvdec.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/libavformat/mlvdec.c b/libavformat/mlvdec.c > > index dae13cae53..03aed71024 100644 > > --- a/libavformat/mlvdec.c > > +++ b/libavformat/mlvdec.c > > @@ -393,10 +393,14 @@ static int read_packet(AVFormatContext *avctx, AVPacket *pkt) > > { > > MlvContext *mlv = avctx->priv_data; > > AVIOContext *pb; > > - AVStream *st = avctx->streams[mlv->stream_index]; > > + AVStream *st; > > int index, ret; > > unsigned int size, space; > > > > + if (!avctx->nb_streams) > > + return AVERROR_EOF; > > Shouldn't you abort during read_header() instead if no streams are ever > allocated? read_header() should fail if the haeder is invalid. is there something which says that "no streams" is invalid ? As it is the read_header() code contains a if() which only make a difference for a "no stream" case. Which gave me the feeling that it wasnt intended to fail in that case but i can add the check for no streams in there where theres already a check for that in read_header ... thx [...]
On 5/31/2020 6:48 PM, Michael Niedermayer wrote: > On Sun, May 31, 2020 at 10:58:16AM -0300, James Almer wrote: >> On 5/31/2020 10:50 AM, Michael Niedermayer wrote: >>> Fixes: NULL pointer dereference >>> Fixes: 22604/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5667739074297856.fuzz >>> >>> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg >>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> >>> --- >>> libavformat/mlvdec.c | 6 +++++- >>> 1 file changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/libavformat/mlvdec.c b/libavformat/mlvdec.c >>> index dae13cae53..03aed71024 100644 >>> --- a/libavformat/mlvdec.c >>> +++ b/libavformat/mlvdec.c >>> @@ -393,10 +393,14 @@ static int read_packet(AVFormatContext *avctx, AVPacket *pkt) >>> { >>> MlvContext *mlv = avctx->priv_data; >>> AVIOContext *pb; >>> - AVStream *st = avctx->streams[mlv->stream_index]; >>> + AVStream *st; >>> int index, ret; >>> unsigned int size, space; >>> >>> + if (!avctx->nb_streams) >>> + return AVERROR_EOF; >> >> Shouldn't you abort during read_header() instead if no streams are ever >> allocated? > > read_header() should fail if the haeder is invalid. > is there something which says that "no streams" is invalid ? > > As it is the read_header() code contains a if() which only make > a difference for a "no stream" case. Which gave me the feeling that > it wasnt intended to fail in that case The checks i'm seeing are all considering video only, audio only, or both, like the very last check in the function where there's no last resort else that would cover a no streams case. > but i can add the check for no streams in there where theres already > a check for that in read_header ... Unless there's something in a file that could be signaled without streams (All the metadata strings in scan_file() look like they definitely apply to some video or audio stream), such a file seems odd to me, and if the end result will be just signaling EOF as soon as the first attempt at fetching a packet, then might as well just abort in read_header() and save the library caller further processing. Maybe Peter Ross can comment. But in any case, no strong feelings about it, so apply whatever you think is best. > > thx > > [...] > > > _______________________________________________ > 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 Sun, May 31, 2020 at 07:07:11PM -0300, James Almer wrote: > On 5/31/2020 6:48 PM, Michael Niedermayer wrote: > > On Sun, May 31, 2020 at 10:58:16AM -0300, James Almer wrote: > >> On 5/31/2020 10:50 AM, Michael Niedermayer wrote: > >>> Fixes: NULL pointer dereference > >>> Fixes: 22604/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5667739074297856.fuzz > >>> > >>> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > >>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > >>> --- > >>> libavformat/mlvdec.c | 6 +++++- > >>> 1 file changed, 5 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/libavformat/mlvdec.c b/libavformat/mlvdec.c > >>> index dae13cae53..03aed71024 100644 > >>> --- a/libavformat/mlvdec.c > >>> +++ b/libavformat/mlvdec.c > >>> @@ -393,10 +393,14 @@ static int read_packet(AVFormatContext *avctx, AVPacket *pkt) > >>> { > >>> MlvContext *mlv = avctx->priv_data; > >>> AVIOContext *pb; > >>> - AVStream *st = avctx->streams[mlv->stream_index]; > >>> + AVStream *st; > >>> int index, ret; > >>> unsigned int size, space; > >>> > >>> + if (!avctx->nb_streams) > >>> + return AVERROR_EOF; > >> > >> Shouldn't you abort during read_header() instead if no streams are ever > >> allocated? > > > > read_header() should fail if the haeder is invalid. > > is there something which says that "no streams" is invalid ? > > > > As it is the read_header() code contains a if() which only make > > a difference for a "no stream" case. Which gave me the feeling that > > it wasnt intended to fail in that case > > The checks i'm seeing are all considering video only, audio only, or > both, like the very last check in the function where there's no last > resort else that would cover a no streams case. if (vst && ast) A else if (vst) B else if (ast) C if one didnt think of "no streams" this would be if (vst && ast) A else if (vst) B else C if one wanted to reject "no streams" this would be if (vst && ast) A else if (vst) B else if (ast) C else FAIL to me this looked like the intend was to support that I have no preferrance between any of this, just wanted to not error out on a path that seemed the author didnt want it to error ... > > > but i can add the check for no streams in there where theres already > > a check for that in read_header ... > > Unless there's something in a file that could be signaled without > streams (All the metadata strings in scan_file() look like they > definitely apply to some video or audio stream), such a file seems odd > to me, and if the end result will be just signaling EOF as soon as the > first attempt at fetching a packet, then might as well just abort in > read_header() and save the library caller further processing. > > Maybe Peter Ross can comment. But in any case, no strong feelings about > it, so apply whatever you think is best. ok, ill wait for peter to reply then or in absence of a reply, next time i remember ill apply something thanks [...]
On Mon, Jun 01, 2020 at 11:51:41PM +0200, Michael Niedermayer wrote: > On Sun, May 31, 2020 at 07:07:11PM -0300, James Almer wrote: > > On 5/31/2020 6:48 PM, Michael Niedermayer wrote: > > > On Sun, May 31, 2020 at 10:58:16AM -0300, James Almer wrote: > > >> On 5/31/2020 10:50 AM, Michael Niedermayer wrote: > > >>> Fixes: NULL pointer dereference > > >>> Fixes: 22604/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5667739074297856.fuzz > > >>> > > >>> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > >>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > >>> --- > > >>> libavformat/mlvdec.c | 6 +++++- > > >>> 1 file changed, 5 insertions(+), 1 deletion(-) > > >>> > > >>> diff --git a/libavformat/mlvdec.c b/libavformat/mlvdec.c > > >>> index dae13cae53..03aed71024 100644 > > >>> --- a/libavformat/mlvdec.c > > >>> +++ b/libavformat/mlvdec.c > > >>> @@ -393,10 +393,14 @@ static int read_packet(AVFormatContext *avctx, AVPacket *pkt) > > >>> { > > >>> MlvContext *mlv = avctx->priv_data; > > >>> AVIOContext *pb; > > >>> - AVStream *st = avctx->streams[mlv->stream_index]; > > >>> + AVStream *st; > > >>> int index, ret; > > >>> unsigned int size, space; > > >>> > > >>> + if (!avctx->nb_streams) > > >>> + return AVERROR_EOF; > > >> > > >> Shouldn't you abort during read_header() instead if no streams are ever > > >> allocated? > > > > > > read_header() should fail if the haeder is invalid. > > > is there something which says that "no streams" is invalid ? > > > > > > As it is the read_header() code contains a if() which only make > > > a difference for a "no stream" case. Which gave me the feeling that > > > it wasnt intended to fail in that case > > > > The checks i'm seeing are all considering video only, audio only, or > > both, like the very last check in the function where there's no last > > resort else that would cover a no streams case. > > if (vst && ast) > A > else if (vst) > B > else if (ast) > C > > if one didnt think of "no streams" this would be > if (vst && ast) > A > else if (vst) > B > else > C > > if one wanted to reject "no streams" this would be > > if (vst && ast) > A > else if (vst) > B > else if (ast) > C > else > FAIL > > to me this looked like the intend was to support that > > I have no preferrance between any of this, just wanted to not error > out on a path that seemed the author didnt want it to error ... > > > > > > > but i can add the check for no streams in there where theres already > > > a check for that in read_header ... > > > > Unless there's something in a file that could be signaled without > > streams (All the metadata strings in scan_file() look like they > > definitely apply to some video or audio stream), such a file seems odd > > to me, and if the end result will be just signaling EOF as soon as the > > first attempt at fetching a packet, then might as well just abort in > > read_header() and save the library caller further processing. > > > > Maybe Peter Ross can comment. But in any case, no strong feelings about > > it, so apply whatever you think is best. > > ok, ill wait for peter to reply then or in absence of a reply, next time > i remember ill apply something just remembered, so will apply, feel free to replace by another solution or if peter comes across this in the future. iam happy to replace it but trying to move forward, leaving it open is worst thx [...]
diff --git a/libavformat/mlvdec.c b/libavformat/mlvdec.c index dae13cae53..03aed71024 100644 --- a/libavformat/mlvdec.c +++ b/libavformat/mlvdec.c @@ -393,10 +393,14 @@ static int read_packet(AVFormatContext *avctx, AVPacket *pkt) { MlvContext *mlv = avctx->priv_data; AVIOContext *pb; - AVStream *st = avctx->streams[mlv->stream_index]; + AVStream *st; int index, ret; unsigned int size, space; + if (!avctx->nb_streams) + return AVERROR_EOF; + + st = avctx->streams[mlv->stream_index]; if (mlv->pts >= st->duration) return AVERROR_EOF;
Fixes: NULL pointer dereference Fixes: 22604/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5667739074297856.fuzz Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavformat/mlvdec.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)