[FFmpeg-devel] [PATCH] avformat/avidec: Fix memleak when error happens after creating DV stream

[Andreas Rheinhardt]

Michael Niedermayer:
> On Wed, Aug 19, 2020 at 12:00:37AM +0200, Andreas Rheinhardt wrote:
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
>> ---
>> The memleak can be reproduced with e.g. the first 163 bytes of
>> https://samples.ffmpeg.org/archive/all/avi+dvvideo+pcm_s16le++ffmpeg-avidec554-crash.avi
>>
>>  libavformat/avidec.c | 31 +++++++++++++++++--------------
>>  1 file changed, 17 insertions(+), 14 deletions(-)
>>
>> diff --git a/libavformat/avidec.c b/libavformat/avidec.c
>> index 5fc3e01aa9..08b864f19a 100644
>> --- a/libavformat/avidec.c
>> +++ b/libavformat/avidec.c
>> @@ -113,6 +113,7 @@ static const AVMetadataConv avi_metadata_conv[] = {
>>      { 0 },
>>  };
>>  
>> +static int avi_read_close(AVFormatContext *s);
>>  static int avi_load_index(AVFormatContext *s);
>>  static int guess_ni_flag(AVFormatContext *s);
>>  
>> @@ -464,6 +465,7 @@ static int calculate_bitrate(AVFormatContext *s)
>>      return 1;
>>  }
>>  
>> +#define RETURN_ERROR(code) do { ret = (code); goto fail; } while (0)
>>  static int avi_read_header(AVFormatContext *s)
>>  {
>>      AVIContext *avi = s->priv_data;
>> @@ -499,7 +501,7 @@ static int avi_read_header(AVFormatContext *s)
>>      frame_period = 0;
>>      for (;;) {
>>          if (avio_feof(pb))
>> -            goto fail;
>> +            RETURN_ERROR(AVERROR_INVALIDDATA);
> 
> this macro is messy
> it replaces writing 
> {ret = AVERROR_INVALIDDATA; goto fail;}
> by
> RETURN_ERROR(AVERROR_INVALIDDATA);
> 
> this is almost the same length but the first is directly understood C code
> the 2nd is harder to understand for someone reading the code so i  
> suggest to avoid the 2nd and use something else, not saying that needs to
> be the first
> 
The only reason this macro exists is because it allows me to add code
that can easily be removed lateron when cleaning up after read_header
failure will be automatic, whereas an

if (foo) {
    ret = bar;
    goto fail;
}

leads to a bigger diff now and later. If you want to, I could of course use
if (foo)
    { ret = bar; goto fail; }

- Andreas