[FFmpeg-devel,1/3] avformat/4xm: Cleanup on GET_LIST_HEADER() failure

Fixes: memleak
Fixes: 23142/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5932860820422656

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/4xm.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Michael Niedermayer:
> Fixes: memleak
> Fixes: 23142/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5932860820422656
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavformat/4xm.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/libavformat/4xm.c b/libavformat/4xm.c
> index aea9226984..5f0504b13e 100644
> --- a/libavformat/4xm.c
> +++ b/libavformat/4xm.c
> @@ -59,8 +59,10 @@
>  #define GET_LIST_HEADER() \
>      fourcc_tag = avio_rl32(pb); \
>      size       = avio_rl32(pb); \
> -    if (fourcc_tag != LIST_TAG) \
> -        return AVERROR_INVALIDDATA; \
> +    if (fourcc_tag != LIST_TAG) { \
> +        ret = AVERROR_INVALIDDATA; \
> +        goto fail; \
> +    } \
>      fourcc_tag = avio_rl32(pb);
>  
>  typedef struct AudioTrack {
> @@ -210,7 +212,7 @@ static int fourxm_read_header(AVFormatContext *s)
>      unsigned int size;
>      int header_size;
>      FourxmDemuxContext *fourxm = s->priv_data;
> -    unsigned char *header;
> +    unsigned char *header = NULL;
>      int i, ret;
>  
>      fourxm->track_count = 0;
> 
LGTM.
(Alternatively, one could av_freep header immediately after the loop
before the second occurrence of GET_LIST_HEADER.)

- Andreas

On Sun, Jun 07, 2020 at 10:21:56PM +0200, Andreas Rheinhardt wrote:
> Michael Niedermayer:
> > Fixes: memleak
> > Fixes: 23142/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5932860820422656
> > 
> > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >  libavformat/4xm.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> > 
> > diff --git a/libavformat/4xm.c b/libavformat/4xm.c
> > index aea9226984..5f0504b13e 100644
> > --- a/libavformat/4xm.c
> > +++ b/libavformat/4xm.c
> > @@ -59,8 +59,10 @@
> >  #define GET_LIST_HEADER() \
> >      fourcc_tag = avio_rl32(pb); \
> >      size       = avio_rl32(pb); \
> > -    if (fourcc_tag != LIST_TAG) \
> > -        return AVERROR_INVALIDDATA; \
> > +    if (fourcc_tag != LIST_TAG) { \
> > +        ret = AVERROR_INVALIDDATA; \
> > +        goto fail; \
> > +    } \
> >      fourcc_tag = avio_rl32(pb);
> >  
> >  typedef struct AudioTrack {
> > @@ -210,7 +212,7 @@ static int fourxm_read_header(AVFormatContext *s)
> >      unsigned int size;
> >      int header_size;
> >      FourxmDemuxContext *fourxm = s->priv_data;
> > -    unsigned char *header;
> > +    unsigned char *header = NULL;
> >      int i, ret;
> >  
> >      fourxm->track_count = 0;
> > 
> LGTM.

will apply

thx

> (Alternatively, one could av_freep header immediately after the loop
> before the second occurrence of GET_LIST_HEADER.)

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