diff mbox series

[FFmpeg-devel,1/4] avcodec/av1dec: Check for unset obu instead of crashing

Message ID 20201025230059.16740-1-michael@niedermayer.cc
State Accepted
Commit 718e862da3e254c58447c0873decb335f688fa09
Headers show
Series [FFmpeg-devel,1/4] avcodec/av1dec: Check for unset obu instead of crashing
Related show

Checks

Context Check Description
andriy/x86_make success Make finished
andriy/x86_make_fate success Make fate finished

Commit Message

Michael Niedermayer Oct. 25, 2020, 11 p.m. UTC
Fixes: NULL pointer dereference
Fixes: 26550/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AV1_fuzzer-5417762807349248

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/av1dec.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

James Almer Oct. 26, 2020, midnight UTC | #1
On 10/25/2020 8:00 PM, Michael Niedermayer wrote:
> Fixes: NULL pointer dereference
> Fixes: 26550/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AV1_fuzzer-5417762807349248
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/av1dec.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/libavcodec/av1dec.c b/libavcodec/av1dec.c
> index a0a279d65b..bb4295aa6f 100644
> --- a/libavcodec/av1dec.c
> +++ b/libavcodec/av1dec.c
> @@ -673,7 +673,12 @@ static int av1_decode_frame(AVCodecContext *avctx, void *frame,
>      for (int i = 0; i < s->current_obu.nb_units; i++) {
>          CodedBitstreamUnit *unit = &s->current_obu.units[i];
>          AV1RawOBU *obu = unit->content;
> -        const AV1RawOBUHeader *header = &obu->header;
> +        const AV1RawOBUHeader *header;
> +
> +        if (!obu)

This looks like a "regression" since ae7686a64f, where ENOSYS (an error
code that's not propagated to the caller) on unsupported OBU types is
now returned before cbs_av1 even gets a chance to allocate the unit's
content.

Should be ok.

> +            continue;
> +
> +        header = &obu->header;
>          av_log(avctx, AV_LOG_DEBUG, "Obu idx:%d, obu type:%d.\n", i, unit->type);
>  
>          switch (unit->type) {
>
Michael Niedermayer Oct. 26, 2020, 6:45 p.m. UTC | #2
On Sun, Oct 25, 2020 at 09:00:53PM -0300, James Almer wrote:
> On 10/25/2020 8:00 PM, Michael Niedermayer wrote:
> > Fixes: NULL pointer dereference
> > Fixes: 26550/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AV1_fuzzer-5417762807349248
> > 
> > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >  libavcodec/av1dec.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/libavcodec/av1dec.c b/libavcodec/av1dec.c
> > index a0a279d65b..bb4295aa6f 100644
> > --- a/libavcodec/av1dec.c
> > +++ b/libavcodec/av1dec.c
> > @@ -673,7 +673,12 @@ static int av1_decode_frame(AVCodecContext *avctx, void *frame,
> >      for (int i = 0; i < s->current_obu.nb_units; i++) {
> >          CodedBitstreamUnit *unit = &s->current_obu.units[i];
> >          AV1RawOBU *obu = unit->content;
> > -        const AV1RawOBUHeader *header = &obu->header;
> > +        const AV1RawOBUHeader *header;
> > +
> > +        if (!obu)
> 
> This looks like a "regression" since ae7686a64f, where ENOSYS (an error
> code that's not propagated to the caller) on unsupported OBU types is
> now returned before cbs_av1 even gets a chance to allocate the unit's
> content.
> 

> Should be ok.

will apply

thx

[...]
diff mbox series

Patch

diff --git a/libavcodec/av1dec.c b/libavcodec/av1dec.c
index a0a279d65b..bb4295aa6f 100644
--- a/libavcodec/av1dec.c
+++ b/libavcodec/av1dec.c
@@ -673,7 +673,12 @@  static int av1_decode_frame(AVCodecContext *avctx, void *frame,
     for (int i = 0; i < s->current_obu.nb_units; i++) {
         CodedBitstreamUnit *unit = &s->current_obu.units[i];
         AV1RawOBU *obu = unit->content;
-        const AV1RawOBUHeader *header = &obu->header;
+        const AV1RawOBUHeader *header;
+
+        if (!obu)
+            continue;
+
+        header = &obu->header;
         av_log(avctx, AV_LOG_DEBUG, "Obu idx:%d, obu type:%d.\n", i, unit->type);
 
         switch (unit->type) {