  t42_parse_font_matrix( T42_Face    face,
                         T42_Loader  loader )
  {
    T42_Parser  parser = &loader->parser;
    FT_Matrix*  matrix = &face->type1.font_matrix;
    FT_Vector*  offset = &face->type1.font_offset;
     FT_Face     root   = (FT_Face)&face->root;
     FT_Fixed    temp[6];
     FT_Fixed    temp_scale;
    FT_Int      result;
 
 
    result = T1_ToFixedArray( parser, 6, temp, 3 );

    if ( result < 6 )
    {
      parser->root.error = FT_THROW( Invalid_File_Format );
      return;
    }
 
     temp_scale = FT_ABS( temp[3] );
 
    if ( temp_scale == 0 )
    {
      FT_ERROR(( "t1_parse_font_matrix: invalid font matrix\n" ));
      parser->root.error = FT_THROW( Invalid_File_Format );
      return;
    }

     /* Set Units per EM based on FontMatrix values.  We set the value to */
     /* 1000 / temp_scale, because temp_scale was already multiplied by   */
     /* 1000 (in t1_tofixed, from psobjs.c).                              */
    matrix->xx = temp[0];
    matrix->yx = temp[1];
    matrix->xy = temp[2];
    matrix->yy = temp[3];

    /* note that the offsets must be expressed in integer font units */
    offset->x = temp[4] >> 16;
    offset->y = temp[5] >> 16;
       temp[2] = FT_DivFix( temp[2], temp_scale );
       temp[4] = FT_DivFix( temp[4], temp_scale );
       temp[5] = FT_DivFix( temp[5], temp_scale );
      temp[3] = temp[3] < 0 ? -0x10000L : 0x10000L;
     }

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.