[FFmpeg-devel] [PATCH v5 2/3] libavformat/rtsp: Free memory allocated for temporary variables while processing sdp info

[Rashad Tatum]

So, perhaps sdp_parse_line should not be void and should propagate an error
code up that should be returned by ff_sdp_parse.

On Wed, Feb 26, 2025, 8:16 AM Rashad Tatum <tatum.rashad at gmail.com> wrote:

> In other parts of the ffmpeg code base where the return type is not void
> for the function, NULL is returned and then the caller typically returns
> AVERROR.
>
> Strangely, sdp_parse_line is void and it seems like ff_sdp_parse always
> returns 0, despite the caller (sdp_read_header) attempting to handle any
> potential returned error codes.
>
> On Wed, Feb 26, 2025, 7:52 AM Rashad Tatum <tatum.rashad at gmail.com> wrote:
>
>> As a side note,  I think the failure of the rtsp_src memory allocation
>> should also log an error so that the user is aware of why the rtsp stream
>> failed to play. However, I think this change should be part of separate
>> patch series.
>>
>> On Wed, Feb 26, 2025, 7:14 AM Rashad Tatum <tatum.rashad at gmail.com>
>> wrote:
>>
>>> Ok. I'll move this and the third patch to one commit/patch and also
>>> change the condition when rtsp_src can't be allocated to also free
>>> dest_addr. Good catch.
>>>
>>>
>>> On Wed, Feb 26, 2025, 3:53 AM Andreas Rheinhardt <
>>> andreas.rheinhardt at outlook.com> wrote:
>>>
>>>> Rashad Tatum:
>>>> > ---
>>>> >  libavformat/rtsp.c | 2 ++
>>>> >  1 file changed, 2 insertions(+)
>>>> >
>>>> > diff --git a/libavformat/rtsp.c b/libavformat/rtsp.c
>>>> > index 0c65f8d1a4..ac17717195 100644
>>>> > --- a/libavformat/rtsp.c
>>>> > +++ b/libavformat/rtsp.c
>>>> > @@ -478,6 +478,7 @@ static void sdp_parse_line(AVFormatContext *s,
>>>> SDPParseState *s1,
>>>> >                                                sdp_ip_str);
>>>> >
>>>> >          }
>>>> > +        av_freep(&sdp_ip_str);
>>>> >          break;
>>>> >      case 's':
>>>> >          av_dict_set(&s->metadata, "title", p, 0);
>>>> > @@ -702,6 +703,7 @@ static void sdp_parse_line(AVFormatContext *s,
>>>> SDPParseState *s1,
>>>> >                      }
>>>> >                  }
>>>> >              }
>>>> > +            av_freep(&dest_addr);
>>>> >          } else {
>>>> >              if (rt->server_type == RTSP_SERVER_WMS)
>>>> >                  ff_wms_parse_sdp_a_line(s, p);
>>>>
>>>> Your first patch introduces a memleak; the stuff you allocated there
>>>> should be freed in the patch, not fixed up in a later patch.
>>>> (Also note that there must not be a leak in any error path, which is not
>>>> true when your patchset is applied: dest_addr leaks when rtsp_src can't
>>>> be allocated.)
>>>>
>>>> - Andreas
>>>>
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>>>