[vlc-devel] [PATCH] added handling of wrong MIME boundary separator to mjpeg demux

[Hugo Beauzée-Luyssen]

On Tue, Aug 28, 2012 at 10:45 AM, Sergey Radionov <rsatom at gmail.com> wrote:
> 2012/8/26 Sergey Radionov <rsatom at gmail.com>:
>> ---
>>  modules/demux/mjpeg.c |   83 ++++++++++++++++++++++++++++++++++++++++++++----
>>  1 files changed, 76 insertions(+), 7 deletions(-)
>>
>> diff --git a/modules/demux/mjpeg.c b/modules/demux/mjpeg.c
>> index a057db3..055a908 100644
>> --- a/modules/demux/mjpeg.c
>> +++ b/modules/demux/mjpeg.c
>> @@ -200,10 +200,10 @@ static bool CheckMimeHeader( demux_t *p_demux, int *p_header_size )
>>              char *content_type = stream_ContentType( p_demux->s );
>>              if ( content_type == NULL )
>>                  return false;
>> -            const char* boundary = strstr( content_type, "boundary=--" );
>> +            const char* boundary = strstr( content_type, "boundary=" );
>>              if ( boundary != NULL )
>>              {
>> -                p_sys->psz_separator = strdup( boundary + strlen( "boundary=--" ) );
>> +                p_sys->psz_separator = strdup( boundary + sizeof("boundary=") - 1 );
>>                  msg_Dbg( p_demux, "Video boundary extracted from Content-Type: %s", p_sys->psz_separator );
>>                  free( content_type );
>>                  /* Skip to HTTP header parsing as there's no boundary to extract
>> @@ -223,7 +223,8 @@ static bool CheckMimeHeader( demux_t *p_demux, int *p_header_size )
>>      }
>>      else
>>      {
>> -        i_pos = *p_sys->p_peek == '-' ? 2 : 4;
>> +        i_pos = *p_sys->p_peek == '-' ? 0 : 2;//skip "\r\n" if exist
>> +        int i_pos_save = i_pos;//to allow restore after missing "\r\n"...
>>          psz_line = GetLine( p_demux, &i_pos );
>>          if( NULL == psz_line )
>>          {
>> @@ -235,13 +236,77 @@ static bool CheckMimeHeader( demux_t *p_demux, int *p_header_size )
>>          /* Read the separator and remember it if not yet stored */
>>          if( p_sys->psz_separator == NULL )
>>          {
>> -            p_sys->psz_separator = psz_line;
>> -            msg_Dbg( p_demux, "Multipart MIME detected, using separator: %s",
>> -                     p_sys->psz_separator );
>> +            char *content_type = stream_ContentType( p_demux->s );
>> +            char* boundary = NULL;
>> +            if ( content_type != NULL )
>> +            {
>> +                boundary = strstr( content_type, "boundary=" );
>> +                if( boundary ) boundary += sizeof("boundary=") - 1;
>> +            }
>> +
>> +            //some vendors add "--" at boundary begin and end in ContentType declaration,
>> +            //and don't add additional "--" in the body - it's incorrect...
>> +            //some other vendors, forget to add "\r\n" after boundary - it's incorrect too...
>> +            //and some else vendors, forget to add "\r\n" and forget to add "--" both
>> +            //(or add excess "--" to ContentType, which is the same)...
>> +
>> +            size_t bl = boundary ? strlen(boundary) : 0;
>> +            //if used boundary without additional "--"
>> +            //(i.e. used same string was declared in ContentType), then
>> +            if( boundary && !strncmp( psz_line, boundary, bl ) )
>> +            {
>> +                //if boundary identical to psz_line, then
>> +                if( (psz_line + bl) == '\0' )
>> +                {
>> +                    //just use whole line as separator
>> +                    p_sys->psz_separator = psz_line;
>> +                }
>> +                else
>> +                {
>> +                    //restore buffer position to right place
>> +                    i_pos = i_pos_save + bl;
>> +                    p_sys->psz_separator = strdup( boundary );
>> +                    free( psz_line );
>> +                }
>> +            }
>> +
>> +            //if used boundary with additional "--"
>> +            if( !p_sys->psz_separator && boundary &&
>> +                !strncmp( psz_line + sizeof("--") - 1, boundary, bl ) )
>> +            {
>> +                char* s = psz_line + sizeof("--") - 1 + bl;
>> +                if( !strncmp( s , "--", 2 ) ) //skip "--" if boundary is last
>> +                    s += 2;
>> +
>> +                //"\r\n" is forgotten
>> +                if ( s != '\0' ) {
>> +                    //restore buffer position to right place
>> +                    i_pos = i_pos_save + bl;
>> +                }
>> +
>> +                p_sys->psz_separator = strdup( boundary );
>> +                free( psz_line );
>> +            }
>> +
>> +            if( !p_sys->psz_separator )
>> +            {
>> +                //separator was not found, then just use whole line
>> +                //FIXME: don't sure it's right
>> +                p_sys->psz_separator = psz_line;
>> +            }
>> +
>> +            if ( p_sys->psz_separator ) {
>> +                msg_Dbg( p_demux, "Multipart MIME detected, using separator: %s",
>> +                         p_sys->psz_separator );
>> +            }
>> +
>> +            free( content_type );
>>          }
>>          else
>>          {
>> -            if( strcmp( psz_line, p_sys->psz_separator ) )
>> +            size_t sl = strlen(p_sys->psz_separator);
>> +            if( strncmp( psz_line + sizeof("--") - 1, p_sys->psz_separator, sl ) &&
>> +                strncmp( psz_line, p_sys->psz_separator, sl ) )
>>              {
>>                  msg_Warn( p_demux, "separator %s does not match %s", psz_line,
>>                            p_sys->psz_separator );
>> @@ -527,7 +592,11 @@ static int MimeDemux( demux_t *p_demux )
>>              }
>>          }
>>
>> +        //some vendors use as separator same string which was defined in ContentType
>> +        //without additional "--"
>>          if( !strncmp( p_sys->psz_separator, (char *)(p_sys->p_peek + i + 2),
>> +                      strlen( p_sys->psz_separator ) ) ||
>> +            !strncmp( p_sys->psz_separator, (char *)(p_sys->p_peek + i),
>>                        strlen( p_sys->psz_separator ) ) )
>>          {
>>              break;
>> --
>> 1.7.7.1.msysgit.0
>>
>
> don't forget please....
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I'll review it soon(ish).
Do you have some sample stream to test your patch with?

Regards

-- 
Hugo Beauzée-Luyssen
mail: hugo at beauzee.fr
skype: beauze.h