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  1. /*
  2.  * Copyright (C) 2006 Manuel Mausz (manuel@mausz.at)
  3.  * Origin code copyright (c) mjd@digitaleveryware.com 2003
  4.  *  (http://www.digitaleveryware.com/projects/greylisting/)
  5.  *
  6.  * This program is free software; you can redistribute it and/or
  7.  * modify it under the terms of the GNU General Public License
  8.  * as published by the Free Software Foundation; either
  9.  * version 2 of the License, or (at your option) any later
  10.  * version.
  11.  *
  12.  * This program is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15.  * GNU General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU General Public License
  18.  * along with this program; if not, write to the Free Software Foundation,
  19.  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20.  */
  21.  
  22. #include <stdio.h>
  23. #include <stdlib.h>
  24. #include <string.h>
  25. #include <stdarg.h>
  26. #include <errno.h>
  27. #include <mysql.h>
  28.  
  29. #define SQLCMDSIZE     2048
  30. #define RET_NOTFOUND   0
  31. #define RET_ACCEPT     1
  32. #define RET_REJECT     2
  33. #define RET_TEMPREJECT 3
  34. #define CMD_TEMPREJECT "E451 temporary failure (#4.3.0)\n"
  35. #define CMD_REJECT     "E553 sorry, your envelope sender has been denied (#5.7.1)\n"
  36. #define LOGLEVEL_FATAL 1
  37. #define LOGLEVEL_ERROR 2
  38. #define LOGLEVEL_WARN  3
  39. #define LOGLEVEL_INFO  4
  40. #define LOGLEVEL_DEBUG 5
  41. #define MAXCONFIGLINESIZE 1024 // maybe change this to dynamic allocation sometime
  42. #if MYSQL_VERSION_ID >= 50003
  43. # define QUERYSIZE 500
  44. #else
  45. # define QUERYSIZE 700
  46. #endif
  47.  
  48. static char *configfile = "control/greylisting";
  49. static char *mysql_host = NULL;
  50. static char *mysql_user = NULL;
  51. static char *mysql_pass = NULL;
  52. static char *mysql_db   = NULL;
  53. unsigned int mysql_port = 3306;
  54. unsigned int block_expire  = 55;
  55. unsigned int record_expire = 500;
  56. unsigned int record_expire_good = 36;
  57. static char *relay_ip;
  58. static int loglevel = LOGLEVEL_WARN;
  59.  
  60. void gllog(unsigned int level,  char* format, ...)
  61. {
  62.   va_list args;
  63.   if (level > loglevel)
  64.     return;
  65.   va_start(args, format);
  66.   vfprintf(stderr, format, args);
  67.   va_end(args);
  68. }
  69.  
  70. int load_config(void)
  71. {
  72.   char *tmp;
  73.   FILE *config;
  74.   char buf[MAXCONFIGLINESIZE];
  75.   int i;
  76.  
  77.   /* first check for logging var */
  78.   tmp = getenv("GLLOGLEVEL");
  79.   if (tmp)
  80.     loglevel = atoi(tmp);
  81.  
  82.   /* check if greylisting is enabled */
  83.   if (!getenv("GREYLISTING") || getenv("RELAYCLIENT"))
  84.   {
  85.     gllog(LOGLEVEL_DEBUG, "greylisting: greylisting is not activated\n");
  86.     return 0;
  87.   }
  88.  
  89.   /* basic environment variables needed */
  90.   relay_ip  = getenv("TCPREMOTEIP");
  91.   if (!relay_ip)
  92.   {
  93.     gllog(LOGLEVEL_FATAL, "greylisting: one of the following envvars is not set: TCPREMOTEIP\n");
  94.     return 0;
  95.   }
  96.  
  97.   /* avoid buffer overflows (max. query is ~410 chars long) */
  98.   if (strlen(relay_ip) > SQLCMDSIZE - QUERYSIZE)
  99.   {
  100.     gllog(LOGLEVEL_FATAL, "greylisting: buffer overflow protection occurs\n");
  101.     return 0;
  102.   }
  103.  
  104.   /* fetch config file path */
  105.   tmp = getenv("GLCONFIGFILE");
  106.   if (tmp)
  107.     configfile = tmp;
  108.  
  109.   /* fetch config file content */
  110.   gllog(LOGLEVEL_DEBUG, "greylisting: configfile=%s\n", configfile);
  111.   config = fopen(configfile, "r");
  112.   if (!config)
  113.     gllog(LOGLEVEL_DEBUG, "greylisting: configfile error: %s\n", strerror(errno));
  114.   else
  115.   {
  116.     while((tmp = fgets(buf, sizeof(buf), config)))
  117.     {
  118.       if (buf[0] == '#' || buf[0] == ';')
  119.         continue;
  120.       for(i = 0; i < strlen(buf) && buf[i] != '\r' && buf[i] != '\n'; i++);
  121.       buf[i] = 0;
  122.       if (strstr(tmp, "mysql_host=") == tmp)
  123.       {
  124.         free(mysql_host);
  125.         mysql_host = strdup(tmp + strlen("mysql_host="));
  126.       }
  127.       else if (strstr(tmp, "mysql_port=") == tmp)
  128.         mysql_port = atoi(tmp + strlen("mysql_port="));
  129.       else if (strstr(tmp, "mysql_user=") == tmp)
  130.       {
  131.         free(mysql_user);
  132.         mysql_user = strdup(tmp + strlen("mysql_user="));
  133.       }
  134.       else if (strstr(tmp, "mysql_pass=") == tmp)
  135.       {
  136.         free(mysql_pass);
  137.         mysql_pass = strdup(tmp + strlen("mysql_pass="));
  138.       }
  139.       else if (strstr(tmp, "mysql_db=") == tmp)
  140.       {
  141.         free(mysql_db);
  142.         mysql_db = strdup(tmp + strlen("mysql_db="));
  143.       }
  144.       else if (strstr(tmp, "block_expire=") == tmp)
  145.         block_expire = atoi(tmp + strlen("block_expire="));
  146.       else if (strstr(tmp, "record_expire=") == tmp)
  147.         record_expire = atoi(tmp + strlen("record_expire="));
  148.       else if (strstr(tmp, "record_expire_good=") == tmp)
  149.         record_expire_good = atoi(tmp + strlen("record_expire_good="));
  150.       else if (strstr(tmp, "loglevel=") == tmp && !getenv("GLLOGLEVEL"))
  151.         loglevel = atoi(tmp + strlen("loglevel="));
  152.     }
  153.     fclose(config);
  154.   }
  155.  
  156.   /* environment variables */
  157.   tmp = getenv("GLMYSQLHOST");
  158.   if (tmp)
  159.   {
  160.     free(mysql_host);
  161.     mysql_host = strdup(tmp);
  162.   }
  163.  
  164.   tmp = getenv("GLMYSQLPORT");
  165.   if (tmp)
  166.     mysql_port = atoi(tmp);
  167.  
  168.   tmp = getenv("GLMYSQLUSER");
  169.   if (tmp)
  170.   {
  171.     free(mysql_user);
  172.     mysql_user = strdup(tmp);
  173.   }
  174.  
  175.   tmp = getenv("GLMYSQLPASS");
  176.   if (tmp)
  177.   {
  178.     free(mysql_pass);
  179.     mysql_pass = strdup(tmp);
  180.   }
  181.  
  182.   tmp = getenv("GLMYSQLDB");
  183.   if (tmp)
  184.   {
  185.     free(mysql_db);
  186.     mysql_db = strdup(tmp);
  187.   }
  188.  
  189.   tmp = getenv("GLBLOCKEXPIRE");
  190.   if (tmp)
  191.     block_expire = atoi(tmp);
  192.  
  193.   tmp = getenv("GLRECORDEXPIRE");
  194.   if (tmp)
  195.     record_expire = atoi(tmp);
  196.  
  197.   tmp = getenv("GLRECORDEXPIREGOOD");
  198.   if (tmp)
  199.     record_expire_good = atoi(tmp);
  200.  
  201.   /* logging */
  202.   gllog(LOGLEVEL_DEBUG, "greylisting: mysql: host=%s, port=%d, user=%s, pass=******\n", mysql_host, mysql_port, mysql_user);
  203.   gllog(LOGLEVEL_DEBUG, "greylisting: block_expire=%d, record_expire=%d, record_expire_good=%d\n", block_expire, record_expire, record_expire_good);
  204.   return 1;
  205. }
  206.  
  207. void cleanup()
  208. {
  209.   free(mysql_host);
  210.   free(mysql_user);
  211.   free(mysql_pass);
  212. }
  213.  
  214. int mysql_query_wrapper(MYSQL *mysql, char *query)
  215. {
  216.   int result;
  217.  
  218.   result = mysql_query(mysql, query);
  219.   gllog(LOGLEVEL_DEBUG, "greylisting: mysql: %s - ret=%d\n", query, result);
  220.   return result;
  221. }
  222.  
  223. /* check if relay_ip is white-/blacklisted */
  224. int check_listed(MYSQL *mysql)
  225. {
  226.   MYSQL_RES *res;
  227.   MYSQL_ROW row;
  228.   char query[SQLCMDSIZE];
  229.   int found = RET_NOTFOUND;
  230.  
  231.   sprintf(query, "SET @uipaddr = inet_aton('%s'); ", relay_ip);
  232.   if (mysql_query_wrapper(mysql, query))
  233.   {
  234.     gllog(LOGLEVEL_ERROR, "greylisting: mysql: %s\n", mysql_error(mysql));
  235.     return 0;
  236.   }
  237.  
  238. #if MYSQL_VERSION_ID >= 50003
  239.   sprintf(query,
  240.     "SELECT `id`, `block_expires` >= UTC_TIMESTAMP(), `block_expires` < UTC_TIMESTAMP() "
  241.     "FROM `greylisting_lists` "
  242.     "WHERE `record_expires` > UTC_TIMESTAMP() "
  243.       "AND `ipaddr_start` <= @uipaddr "
  244.       "AND @uipaddr <= `ipaddr_end` "
  245.     "ORDER BY (`ipaddr_end` - `ipaddr_start`) ASC "
  246.     "LIMIT 1");
  247. #else
  248.   sprintf(query,
  249.     "SELECT `id`, `block_expires` >= UTC_TIMESTAMP(), `block_expires` < UTC_TIMESTAMP() "
  250.     "FROM `greylisting_lists` "
  251.     "WHERE `record_expires` > UTC_TIMESTAMP() "
  252.       "AND (@base := IF(INSTR(`ipaddr`, '.'), 32, 128)) "
  253.       "AND IF( "
  254.         "INSTR(`ipaddr`, '/'), "
  255.         "(@ipaddr_start := inet_aton(substring_index(`ipaddr`, '/', 1))) "
  256.         "AND (@ipaddr_count := POW(2, @base - substring_index(`ipaddr`, '/', -1))) "
  257.         "AND (@ipaddr_end := @ipaddr_start + @ipaddr_count - 1), "
  258.         "(@ipaddr_start := inet_aton(`ipaddr`)) "
  259.         "AND (@ipaddr_end := @ipaddr_start) "
  260.       ") "
  261.       "AND @ipaddr_start <= @uipaddr "
  262.       "AND @uipaddr <= @ipaddr_end "
  263.     "ORDER BY (@ipaddr_end - @ipaddr_start) ASC "
  264.     "LIMIT 1");
  265. #endif
  266.  
  267.   if (mysql_query_wrapper(mysql, query) ||
  268.       !(res = mysql_store_result(mysql)))
  269.   {
  270.     gllog(LOGLEVEL_ERROR, "greylisting: mysql: %s\n", mysql_error(mysql));
  271.     return 0;
  272.   }
  273.  
  274.   if ((row = mysql_fetch_row(res)))
  275.   {
  276.     if (atoi(row[1]))
  277.     {
  278.       found = RET_REJECT;
  279.       gllog(LOGLEVEL_INFO, "greylisting: %s is blacklisted (id=%s) - rejecting\n", relay_ip, row[0]);
  280.     }
  281.     else if (atoi(row[2]))
  282.     {
  283.       found = RET_ACCEPT;
  284.       gllog(LOGLEVEL_INFO, "greylisting: %s is whitelisted (id=%s) - accepting\n", relay_ip, row[0]);
  285.     }
  286.   }
  287.  
  288.   mysql_free_result(res);
  289.   return found;
  290. }
  291.  
  292. int check_greylisted(MYSQL *mysql)
  293. {
  294.   MYSQL_RES *res;
  295.   MYSQL_ROW row;
  296.   char query[SQLCMDSIZE];
  297.   char *relay_ip_sub  = NULL;
  298.   char *ptr;
  299.   char ipdelimeter;
  300.   int ret = RET_NOTFOUND;
  301.  
  302.   /*
  303.    * 0 ... query matches anything in the same /24 subnet
  304.    * 1 ... query does an exact ip match
  305.    */
  306.   if (0)
  307.   {
  308.     sprintf(query,
  309.       "SELECT `id`, `block_expires` < UTC_TIMESTAMP() "
  310.       "FROM `greylisting_data` "
  311.       "WHERE `record_expires` > UTC_TIMESTAMP() "
  312.         "AND `relay_ip` = '%s' "
  313.       "LIMIT 1",
  314.       relay_ip);
  315.   }
  316.   else
  317.   {
  318.     /* strip off the last octet */
  319.     ipdelimeter = '.';
  320.     if (!strchr(relay_ip, '.'))
  321.       ipdelimeter = ':';
  322.     relay_ip_sub = strdup(relay_ip);
  323.     ptr = strrchr(relay_ip_sub, ipdelimeter);
  324.     if (ptr)
  325.       *ptr = '\0';
  326.  
  327.     sprintf(query,
  328.       "SELECT `id`, `block_expires` < UTC_TIMESTAMP() "
  329.       "FROM `greylisting_data` "
  330.       "WHERE `record_expires` > UTC_TIMESTAMP() "
  331.         "AND `relay_ip` LIKE '%s%c%%' "
  332.       "LIMIT 1",
  333.       relay_ip_sub,
  334.       ipdelimeter);
  335.     free(relay_ip_sub);
  336.   }
  337.  
  338.   if (mysql_query_wrapper(mysql, query) ||
  339.       !(res = mysql_store_result(mysql)))
  340.   {
  341.     gllog(LOGLEVEL_ERROR, "greylisting: mysql: %s\n", mysql_error(mysql));
  342.     return RET_NOTFOUND;
  343.   }
  344.  
  345.   if ((row = mysql_fetch_row(res)))
  346.   {
  347.     if (atoi(row[1]))
  348.     {
  349.       sprintf(query,
  350.         "UPDATE `greylisting_data` "
  351.         "SET `record_expires` = UTC_TIMESTAMP() + INTERVAL %u DAY, `passed_count` = `passed_count` + 1 "
  352.         "WHERE `id` = '%s'",
  353.         record_expire_good, row[0]);
  354.       ret = RET_ACCEPT;
  355.       gllog(LOGLEVEL_INFO, "greylisting: %s exists (id=%s) - accepting\n", relay_ip, row[0]);
  356.     }
  357.     else
  358.     {
  359.       sprintf(query,
  360.         "UPDATE `greylisting_data` "
  361.         "SET `blocked_count` = `blocked_count` + 1 "
  362.         "WHERE `id` = '%s'",
  363.         row[0]);
  364.       ret = RET_TEMPREJECT;
  365.       gllog(LOGLEVEL_INFO, "greylisting: %s is blocked (id=%s) - temp. rejecting\n", relay_ip, row[0]);
  366.     }
  367.   }
  368.   else
  369.   {
  370.     sprintf(query,
  371.       "INSERT INTO `greylisting_data` "
  372.       "VALUES (0, '%s', '', '', UTC_TIMESTAMP() + INTERVAL %u MINUTE, UTC_TIMESTAMP() + INTERVAL %u MINUTE, 1, 0, 0, UTC_TIMESTAMP(), UTC_TIMESTAMP())",
  373.       relay_ip, block_expire, record_expire);
  374.     ret = RET_TEMPREJECT;
  375.     gllog(LOGLEVEL_INFO, "greylisting: %s doesn't exist. - temp. rejecting\n", relay_ip);
  376.   }
  377.   mysql_free_result(res);
  378.  
  379.   if (mysql_query_wrapper(mysql, query))
  380.   {
  381.     gllog(LOGLEVEL_ERROR, "greylisting: mysql: %s\n", mysql_error(mysql));
  382.     return RET_NOTFOUND;
  383.   }
  384.  
  385.   return ret;
  386. }
  387.  
  388. int main()
  389. {
  390.   int ret = 1;
  391.   int greylisted = 0;
  392.   MYSQL *mysql = NULL;
  393.  
  394.   /* load config */
  395.   if (ret && !load_config())
  396.     ret = 0;
  397.  
  398.   /* connect to mysql */
  399.   if (ret)
  400.   {
  401.     mysql_library_init(-1, NULL, NULL);
  402.     mysql = mysql_init(NULL);
  403.     if (!mysql_real_connect(mysql, mysql_host, mysql_user, mysql_pass, mysql_db, mysql_port, NULL, 0))
  404.     {
  405.       gllog(LOGLEVEL_FATAL, "greylisting: mysql: %s\n", mysql_error(mysql));
  406.       ret = 0;
  407.     }
  408.   }
  409.  
  410.   /* greylisting checks */
  411.   if (ret && !greylisted)
  412.   {
  413.     greylisted = check_listed(mysql);
  414.     if (greylisted == RET_NOTFOUND)
  415.       greylisted = check_greylisted(mysql);
  416.   }
  417.  
  418.   /* print smtp error code */
  419.   if (ret)
  420.   {
  421.     switch(greylisted)
  422.     {
  423.       case RET_REJECT:
  424.         printf(CMD_REJECT);
  425.         break;
  426.       case RET_TEMPREJECT:
  427.         printf(CMD_TEMPREJECT);
  428.         break;
  429.     }
  430.   }
  431.  
  432.   /* cleanup stuff */
  433.   gllog(LOGLEVEL_DEBUG, "greylisting: exiting\n");
  434.   if (mysql)
  435.     mysql_close(mysql);
  436.   mysql_library_end();
  437.   cleanup();
  438.   return !ret;
  439. }
  440.  
  441.