[FFmpeg-devel] [PATCH v1 4/6] avcodec/magicyuv: fix for the memory leak if failed

[Limin Wang]

On Fri, Oct 11, 2019 at 08:00:00AM +0000, Andreas Rheinhardt wrote:
> lance.lmwang at gmail.com:
> > From: Limin Wang <lance.lmwang at gmail.com>
> > 
> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > ---
> >  libavcodec/magicyuv.c | 43 ++++++++++++++++++++++++++++++-------------
> >  1 file changed, 30 insertions(+), 13 deletions(-)
> > 
> > diff --git a/libavcodec/magicyuv.c b/libavcodec/magicyuv.c
> > index 0b1ac7345a..c905c2ca22 100644
> > --- a/libavcodec/magicyuv.c
> > +++ b/libavcodec/magicyuv.c
> > @@ -661,12 +661,16 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> >  
> >      for (i = 0; i < s->planes; i++) {
> >          av_fast_malloc(&s->slices[i], &s->slices_size[i], s->nb_slices * sizeof(Slice));
> > -        if (!s->slices[i])
> > -            return AVERROR(ENOMEM);
> > +        if (!s->slices[i]) {
> > +            ret = AVERROR(ENOMEM);
> > +            goto fail;
> > +        }
> >  
> >          offset = bytestream2_get_le32(&gbyte);
> > -        if (offset >= avpkt->size - header_size)
> > -            return AVERROR_INVALIDDATA;
> > +        if (offset >= avpkt->size - header_size) {
> > +            ret = AVERROR_INVALIDDATA;
> > +            goto fail;
> > +        }
> >  
> >          if (i == 0)
> >              first_offset = offset;
> > @@ -675,8 +679,10 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> >              s->slices[i][j].start = offset + header_size;
> >  
> >              next_offset = bytestream2_get_le32(&gbyte);
> > -            if (next_offset <= offset || next_offset >= avpkt->size - header_size)
> > -                return AVERROR_INVALIDDATA;
> > +            if (next_offset <= offset || next_offset >= avpkt->size - header_size) {
> > +                ret = AVERROR_INVALIDDATA;
> > +                goto fail;
> > +            }
> >  
> >              s->slices[i][j].size = next_offset - offset;
> >              offset = next_offset;
> > @@ -686,28 +692,32 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> >          s->slices[i][j].size  = avpkt->size - s->slices[i][j].start;
> >      }
> >  
> > -    if (bytestream2_get_byte(&gbyte) != s->planes)
> > -        return AVERROR_INVALIDDATA;
> > +    if (bytestream2_get_byte(&gbyte) != s->planes) {
> > +        ret = AVERROR_INVALIDDATA;
> > +        goto fail;
> > +    }
> >  
> >      bytestream2_skip(&gbyte, s->nb_slices * s->planes);
> >  
> >      table_size = header_size + first_offset - bytestream2_tell(&gbyte);
> > -    if (table_size < 2)
> > -        return AVERROR_INVALIDDATA;
> > +    if (table_size < 2) {
> > +        ret = AVERROR_INVALIDDATA;
> > +        goto fail;
> > +    }
> >  
> >      ret = init_get_bits8(&gbit, avpkt->data + bytestream2_tell(&gbyte), table_size);
> >      if (ret < 0)
> > -        return ret;
> > +        goto fail;
> >  
> >      ret = build_huffman(avctx, &gbit, s->max);
> >      if (ret < 0)
> > -        return ret;
> > +        goto fail;
> >  
> >      p->pict_type = AV_PICTURE_TYPE_I;
> >      p->key_frame = 1;
> >  
> >      if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
> > -        return ret;
> > +        goto fail;
> >  
> >      s->buf = avpkt->data;
> >      s->p = p;
> > @@ -736,6 +746,13 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> >      *got_frame = 1;
> >  
> >      return avpkt->size;
> > +
> > +fail:
> > +    for (i = 0; i < FF_ARRAY_ELEMS(s->slices); i++) {
> > +        av_freep(&s->slices[i]);
> > +        s->slices_size[i] = 0;
> > +    }
> > +    return ret;
> >  }
> >  
> >  #if HAVE_THREADS
> > 
> Why should there be a memleak? The slices buffer will be freed in
> magy_decode_end (which is called from avcodec_close() (usually via
> avcodec_free_context()) at the end of the decoding process). So how
> did you detect this memleak?
> 
Have double check it's freed in magy_decode_end, it's my
misunderstanding. Please ignore it.

> - Andreas
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