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

[Sergey Radionov]

2012/8/30 Rémi Denis-Courmont <remi at remlab.net>:
> Sorry, but this is needlessly complicated and hard to read.
> Please simplify the logic.
>
> Le jeudi 30 août 2012 06:18:44 Sergey Radionov, vous avez écrit :
>> ---
>>  modules/demux/mjpeg.c |   94
>> ++++++++++++++++++++++++++++++++++++++++++++++--- 1
> files changed, 89
>> insertions(+), 5 deletions(-)
>>
>> diff --git a/modules/demux/mjpeg.c b/modules/demux/mjpeg.c
>> index a057db3..f5bd1dd 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 + strlen("boundary=") ); 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 +236,92 @@ 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;
>> +            char *content_type = stream_ContentType( p_demux->s );
>> +            char* boundary = NULL;
>> +            if ( content_type != NULL )
>> +            {
>> +                boundary = strstr( content_type, "boundary=" );
>> +                if( boundary ) boundary += strlen("boundary=");
>> +            }
>> +
>> +            //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 boundary_len = 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, boundary_len ) )
>> +            {
>> +                //if boundary identical to psz_line, then
>> +                if( *(psz_line + boundary_len) == '\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 + boundary_len;
>> +                    p_sys->psz_separator = strdup( boundary );
>> +                    free( psz_line );
>> +                    psz_line = NULL;
>> +
>> +                    if( !p_sys->psz_separator )
>> +                    {
>> +                        free( content_type );
>> +                        *p_header_size = -4;
>> +                        return false;
>> +                    }
>> +                }
>> +            }
>> +
>> +            //if used boundary with additional "--"
>> +            if( !p_sys->psz_separator && boundary &&
>> +                !strncmp( psz_line + strlen("--"), boundary, boundary_len
>> ) ) +            {
>> +                char* s = psz_line + strlen("--") + boundary_len;
>> +                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 + boundary_len;
>> +                }
>> +
>> +                p_sys->psz_separator = strdup( boundary );
>> +                free( psz_line );
>> +                psz_line = NULL;
>> +
>> +                if( !p_sys->psz_separator )
>> +                {
>> +                    free( content_type );
>> +                    *p_header_size = -4;
>> +                    return false;
>> +                }
>> +            }
>> +
>> +            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;
>> +            }
>> +
>>              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 separator_len = strlen(p_sys->psz_separator);
>> +            if( strncmp( psz_line + strlen("--"), p_sys->psz_separator,
>> separator_len ) && +                strncmp( psz_line,
>> p_sys->psz_separator, separator_len ) ) {
>>                  msg_Warn( p_demux, "separator %s does not match %s",
>> psz_line, p_sys->psz_separator );
>> @@ -527,7 +607,11 @@ 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;
>
>
> --
> Rémi Denis-Courmont
> C/C++ software engineer looking for a job
> http://www.linkedin.com/in/remidenis
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I've make it as simple as possible, there are to many conditions I
need to check.