[FFmpeg-devel] [PATCH v1 6/8] avformat/mtv: check av_strdup() return value and fix memleak

[Steven Liu]

> 在 2019年10月10日，13:09，zhilizhao(赵志立) <quinkblack at foxmail.com> 写道：
> 
> 
> 
>> On Oct 10, 2019, at 12:59 PM, Steven Liu <lq at chinaffmpeg.org> wrote:
>> 
>> 
>> 
>>> 在 2019年10月10日，12:53，zhilizhao(赵志立) <quinkblack at foxmail.com> 写道：
>>> 
>>> 
>>> 
>>>> On Oct 10, 2019, at 11:40 AM, Steven Liu <lq at chinaffmpeg.org> wrote:
>>>> 
>>>> Signed-off-by: Steven Liu <lq at chinaffmpeg.org>
>>>> ---
>>>> libavformat/mtv.c | 13 +++++++++++--
>>>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>>> 
>>>> diff --git a/libavformat/mtv.c b/libavformat/mtv.c
>>>> index 728f4a4781..c664ae14c7 100644
>>>> --- a/libavformat/mtv.c
>>>> +++ b/libavformat/mtv.c
>>>> @@ -171,13 +171,19 @@ static int mtv_read_header(AVFormatContext *s)
>>>>  st->codecpar->width           = mtv->img_width;
>>>>  st->codecpar->height          = mtv->img_height;
>>>>  st->codecpar->extradata       = av_strdup("BottomUp");
>>>> +    if (!st->codecpar->extradata) {
>>>> +        return AVERROR(ENOMEM);
>>>> +    }
>>>>  st->codecpar->extradata_size  = 9;
>>>> 
>>>>  // audio - mp3
>>>> 
>>>>  st = avformat_new_stream(s, NULL);
>>>> -    if(!st)
>>>> +    if(!st) {
>>>> +        av_freep(&st->codecpar->extradata);
>>>> +        st->codecpar->extradata_size = 0;
>>>>      return AVERROR(ENOMEM);
>>>> +    }
>>> 
>>> NULL pointer dereference?
>> When new streams cannot be create, there have no memory, so release the st->codecpar->extradata,
>> now st->codecpar->extradata is not NULL pointer.
> 
> “st”  is NULL, st->codecpar is NULL pointer dereference.
> 
Ah, get your point.
> PS: I don’t think here is a memory leak.

I think it should free the st->codecpar->extradata before this st = avformat_new_stream(s, NULL);
> 
> 
>> 
>>> 
>>> 
>>>> 
>>>>  avpriv_set_pts_info(st, 64, 1, MTV_AUDIO_SAMPLING_RATE);
>>>>  st->codecpar->codec_type      = AVMEDIA_TYPE_AUDIO;
>>>> @@ -187,8 +193,11 @@ static int mtv_read_header(AVFormatContext *s)
>>>> 
>>>>  // Jump over header
>>>> 
>>>> -    if(avio_seek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE)
>>>> +    if(avio_seek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE) {
>>>> +        av_freep(&st->codecpar->extradata);
>>>> +        st->codecpar->extradata_size = 0;
>>>>      return AVERROR(EIO);
>>>> +    }
>>>> 
>>>>  return 0;
>>>> 
>>>> -- 
>>>> 2.15.1
>>>> 
>>>> 
>>>> 
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>>> 
>>> 
>>> 
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>> 
>> Thanks
>> Steven
>> 
>> 
>> 
>> 
>> 
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Thanks
Steven