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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 char *mail_from;
  59. static char *rcpt_to;
  60. static int loglevel = LOGLEVEL_WARN;
  61.  
  62. void gllog(unsigned int level,  char* format, ...)
  63. {
  64.   va_list args;
  65.   if (level > loglevel)
  66.     return;
  67.   va_start(args, format);
  68.   vfprintf(stderr, format, args);
  69.   va_end(args);
  70. }
  71.  
  72. int load_config(void)
  73. {
  74.   char *tmp, *delim, *atpos;
  75.   FILE *config;
  76.   char buf[MAXCONFIGLINESIZE];
  77.   int i;
  78.   unsigned int userlen;
  79.  
  80.   /* first check for logging var */
  81.   tmp = getenv("GLLOGLEVEL");
  82.   if (tmp)
  83.     loglevel = atoi(tmp);
  84.  
  85.   /* check if greylisting is enabled */
  86.   if (!getenv("GREYLISTING") || getenv("RELAYCLIENT"))
  87.   {
  88.     gllog(LOGLEVEL_DEBUG, "greylisting: greylisting is not enabled\n");
  89.     return 0;
  90.   }
  91.  
  92.   /* basic environment variables needed */
  93.   relay_ip  = getenv("TCPREMOTEIP");
  94.   mail_from = getenv("SMTPMAILFROM");
  95.   rcpt_to   = getenv("SMTPRCPTTO");
  96.   if (!relay_ip || !mail_from || !rcpt_to)
  97.   {
  98.     gllog(LOGLEVEL_FATAL, "greylisting: one of the following envvars is undefined: TCPREMOTEIP, SMTPMAILFROM, SMTPRCPTTO\n");
  99.     return 0;
  100.   }
  101.  
  102.   /* check for BATV ("prvs=X=u@d.t" minimum) */
  103.   if (strlen(mail_from) > 11
  104.       && mail_from[0] == 'p' && mail_from[1] == 'r' && mail_from[2] == 'v'
  105.       && mail_from[3] == 's' && mail_from[4] == '=')
  106.   {
  107.     /* BATV: prvs=HASH=user@domain.tld */
  108.     if ((delim = strchr(mail_from + 5, '=')))
  109.       mail_from = delim + 1;
  110.     /* BATV: prvs=user/HASH@domain.tld */
  111.     else if ((delim = strchr(mail_from + 5, '/')) && (atpos = strchr(delim, '@')))
  112.     {
  113.       userlen = delim - mail_from - 5;
  114.       memmove(atpos - userlen, mail_from + 5, userlen);
  115.       mail_from = atpos - userlen;
  116.     }
  117.   }
  118.  
  119.   /* avoid buffer overflows (max. query is ~410 chars long) */
  120.   if (strlen(relay_ip) + strlen(mail_from) + strlen(rcpt_to) > SQLCMDSIZE - QUERYSIZE)
  121.   {
  122.     gllog(LOGLEVEL_FATAL, "greylisting: buffer overflow protection occurs\n");
  123.     return 0;
  124.   }
  125.  
  126.   /* fetch config file path */
  127.   tmp = getenv("GLCONFIGFILE");
  128.   if (tmp)
  129.     configfile = tmp;
  130.  
  131.   /* fetch config file content */
  132.   gllog(LOGLEVEL_DEBUG, "greylisting: configfile=%s\n", configfile);
  133.   config = fopen(configfile, "r");
  134.   if (!config)
  135.     gllog(LOGLEVEL_DEBUG, "greylisting: configfile error: %s\n", strerror(errno));
  136.   else
  137.   {
  138.     while((tmp = fgets(buf, sizeof(buf), config)))
  139.     {
  140.       if (buf[0] == '#' || buf[0] == ';')
  141.         continue;
  142.       for(i = 0; i < strlen(buf) && buf[i] != '\r' && buf[i] != '\n'; i++);
  143.       buf[i] = 0;
  144.       if (strstr(tmp, "mysql_host=") == tmp)
  145.       {
  146.         free(mysql_host);
  147.         mysql_host = strdup(tmp + strlen("mysql_host="));
  148.       }
  149.       else if (strstr(tmp, "mysql_port=") == tmp)
  150.         mysql_port = atoi(tmp + strlen("mysql_port="));
  151.       else if (strstr(tmp, "mysql_user=") == tmp)
  152.       {
  153.         free(mysql_user);
  154.         mysql_user = strdup(tmp + strlen("mysql_user="));
  155.       }
  156.       else if (strstr(tmp, "mysql_pass=") == tmp)
  157.       {
  158.         free(mysql_pass);
  159.         mysql_pass = strdup(tmp + strlen("mysql_pass="));
  160.       }
  161.       else if (strstr(tmp, "mysql_db=") == tmp)
  162.       {
  163.         free(mysql_db);
  164.         mysql_db = strdup(tmp + strlen("mysql_db="));
  165.       }
  166.       else if (strstr(tmp, "block_expire=") == tmp)
  167.         block_expire = atoi(tmp + strlen("block_expire="));
  168.       else if (strstr(tmp, "record_expire=") == tmp)
  169.         record_expire = atoi(tmp + strlen("record_expire="));
  170.       else if (strstr(tmp, "record_expire_good=") == tmp)
  171.         record_expire_good = atoi(tmp + strlen("record_expire_good="));
  172.       else if (strstr(tmp, "loglevel=") == tmp && !getenv("GLLOGLEVEL"))
  173.         loglevel = atoi(tmp + strlen("loglevel="));
  174.     }
  175.     fclose(config);
  176.   }
  177.  
  178.   /* environment variables */
  179.   tmp = getenv("GLMYSQLHOST");
  180.   if (tmp)
  181.   {
  182.     free(mysql_host);
  183.     mysql_host = strdup(tmp);
  184.   }
  185.  
  186.   tmp = getenv("GLMYSQLPORT");
  187.   if (tmp)
  188.     mysql_port = atoi(tmp);
  189.  
  190.   tmp = getenv("GLMYSQLUSER");
  191.   if (tmp)
  192.   {
  193.     free(mysql_user);
  194.     mysql_user = strdup(tmp);
  195.   }
  196.  
  197.   tmp = getenv("GLMYSQLPASS");
  198.   if (tmp)
  199.   {
  200.     free(mysql_pass);
  201.     mysql_pass = strdup(tmp);
  202.   }
  203.  
  204.   tmp = getenv("GLMYSQLDB");
  205.   if (tmp)
  206.   {
  207.     free(mysql_db);
  208.     mysql_db = strdup(tmp);
  209.   }
  210.  
  211.   tmp = getenv("GLBLOCKEXPIRE");
  212.   if (tmp)
  213.     block_expire = atoi(tmp);
  214.  
  215.   tmp = getenv("GLRECORDEXPIRE");
  216.   if (tmp)
  217.     record_expire = atoi(tmp);
  218.  
  219.   tmp = getenv("GLRECORDEXPIREGOOD");
  220.   if (tmp)
  221.     record_expire_good = atoi(tmp);
  222.  
  223.   /* logging */
  224.   gllog(LOGLEVEL_DEBUG, "greylisting: mysql: host=%s, port=%d, user=%s, pass=******\n", mysql_host, mysql_port, mysql_user);
  225.   gllog(LOGLEVEL_DEBUG, "greylisting: block_expire=%d, record_expire=%d, record_expire_good=%d\n", block_expire, record_expire, record_expire_good);
  226.   return 1;
  227. }
  228.  
  229. void cleanup()
  230. {
  231.   free(mysql_host);
  232.   free(mysql_user);
  233.   free(mysql_pass);
  234. }
  235.  
  236. int mysql_query_wrapper(MYSQL *mysql, char *query)
  237. {
  238.   int result;
  239.  
  240.   result = mysql_query(mysql, query);
  241.   gllog(LOGLEVEL_DEBUG, "greylisting: mysql: %s - ret=%d\n", query, result);
  242.   return result;
  243. }
  244.  
  245. /* check if relay_ip or rcpt_to is white-/blacklisted */
  246. int check_listed(MYSQL *mysql)
  247. {
  248.   MYSQL_RES *res;
  249.   MYSQL_ROW row;
  250.   char query[SQLCMDSIZE];
  251.   int found = RET_NOTFOUND;
  252.   char *domain_esc = NULL;
  253.   char *domain = NULL;
  254.  
  255.   domain = strrchr(rcpt_to, '@');
  256.   /* fallback to full rcpt_to if there's no domain */
  257.   domain = (domain) ? domain + 1 : rcpt_to;
  258.   domain_esc = malloc(strlen(domain)*2 + 1);
  259.   mysql_real_escape_string(mysql, domain_esc, domain, strlen(domain));
  260.   sprintf(query, "SET @uipaddr = inet_aton('%s'), @urcpt_to = '%s'; ", relay_ip, domain_esc);
  261.   if (mysql_query_wrapper(mysql, query))
  262.   {
  263.     gllog(LOGLEVEL_ERROR, "greylisting: mysql: %s\n", mysql_error(mysql));
  264.     return 0;
  265.   }
  266.   free(domain_esc);
  267.  
  268. #if MYSQL_VERSION_ID >= 50003
  269.   sprintf(query,
  270.     "SELECT `id`, `block_expires` >= UTC_TIMESTAMP(), `block_expires` < UTC_TIMESTAMP() "
  271.     "FROM `greylisting_lists` "
  272.     "WHERE `record_expires` > UTC_TIMESTAMP() "
  273.     "AND ( "
  274.       "( "
  275.         "`rcpt_to` IS NULL "
  276.         "AND `ipaddr_start` <= @uipaddr "
  277.         "AND @uipaddr <= `ipaddr_end` "
  278.       ") OR ( "
  279.         "`ipaddr` IS NULL "
  280.         "AND `rcpt_to` = @urcpt_to "
  281.       ") "
  282.     ") "
  283.     "ORDER BY (`ipaddr_end` - `ipaddr_start`) ASC "
  284.     "LIMIT 1");
  285. #else
  286.   sprintf(query,
  287.     "SELECT `id`, `block_expires` >= UTC_TIMESTAMP(), `block_expires` < UTC_TIMESTAMP() "
  288.     "FROM `greylisting_lists` "
  289.     "WHERE `record_expires` > UTC_TIMESTAMP() "
  290.     "AND ( "
  291.       "( "
  292.         "`rcpt_to` IS NULL "
  293.         "AND (@base := IF(INSTR(`ipaddr`, '.'), 32, 128)) "
  294.         "AND IF( "
  295.           "INSTR(`ipaddr`, '/'), "
  296.           "(@ipaddr_start := inet_aton(substring_index(`ipaddr`, '/', 1))) "
  297.           "AND (@ipaddr_count := POW(2, @base - substring_index(`ipaddr`, '/', -1))) "
  298.           "AND (@ipaddr_end := @ipaddr_start + @ipaddr_count - 1), "
  299.           "(@ipaddr_start := inet_aton(`ipaddr`)) "
  300.           "AND (@ipaddr_end := @ipaddr_start) "
  301.         ") "
  302.         "AND @ipaddr_start <= @uipaddr "
  303.         "AND @uipaddr <= @ipaddr_end "
  304.       ") OR ( "
  305.         "`ipaddr` IS NULL "
  306.         "AND `rcpt_to` = @urcpt_to "
  307.       ") "
  308.     ") "
  309.     "ORDER BY (@ipaddr_end - @ipaddr_start) ASC "
  310.     "LIMIT 1");
  311. #endif
  312.  
  313.   if (mysql_query_wrapper(mysql, query) ||
  314.       !(res = mysql_store_result(mysql)))
  315.   {
  316.     gllog(LOGLEVEL_ERROR, "greylisting: mysql: %s\n", mysql_error(mysql));
  317.     return 0;
  318.   }
  319.  
  320.   if ((row = mysql_fetch_row(res)))
  321.   {
  322.     if (atoi(row[1]))
  323.     {
  324.       found = RET_REJECT;
  325.       gllog(LOGLEVEL_INFO, "greylisting: %s/%s is blacklisted (id=%s) - rejecting\n", relay_ip, domain, row[0]);
  326.     }
  327.     else if (atoi(row[2]))
  328.     {
  329.       found = RET_ACCEPT;
  330.       gllog(LOGLEVEL_INFO, "greylisting: %s/%s is whitelisted (id=%s) - accepting\n", relay_ip, domain, row[0]);
  331.     }
  332.   }
  333.  
  334.   mysql_free_result(res);
  335.   return found;
  336. }
  337.  
  338. int check_greylisted(MYSQL *mysql)
  339. {
  340.   MYSQL_RES *res;
  341.   MYSQL_ROW row;
  342.   char query[SQLCMDSIZE];
  343.   char *mail_from_esc = NULL;
  344.   char *rcpt_to_esc   = NULL;
  345.   char *relay_ip_sub  = NULL;
  346.   char *ptr;
  347.   char ipdelimeter;
  348.   int ret = RET_NOTFOUND;
  349.  
  350.   mail_from_esc = malloc(strlen(mail_from)*2 + 1);
  351.   rcpt_to_esc   = malloc(strlen(rcpt_to)*2 + 1);
  352.   mysql_real_escape_string(mysql, mail_from_esc, mail_from, strlen(mail_from));
  353.   mysql_real_escape_string(mysql, rcpt_to_esc, rcpt_to, strlen(rcpt_to));
  354.  
  355.   /*
  356.    * 0 ... query matches anything in the same /24 subnet
  357.    * 1 ... query does an exact ip match
  358.    */
  359.   if (0)
  360.   {
  361.     sprintf(query,
  362.       "SELECT `id`, `block_expires` < UTC_TIMESTAMP() "
  363.       "FROM `greylisting_data` "
  364.       "WHERE `record_expires` > UTC_TIMESTAMP() "
  365.         "AND `relay_ip` = '%s' "
  366.         "AND ( "
  367.           "( "
  368.             "`mail_from` = '%s' "
  369.             "AND `rcpt_to` = '%s' "
  370.           ") OR ( "
  371.             "`mail_from` IS NULL "
  372.             "AND `rcpt_to` IS NULL "
  373.           ") "
  374.         ") "
  375.       "ORDER BY `mail_from` ASC "
  376.       "LIMIT 1",
  377.       relay_ip,
  378.       mail_from_esc,
  379.       rcpt_to_esc);
  380.   }
  381.   else
  382.   {
  383.     /* strip off the last octet */
  384.     ipdelimeter = '.';
  385.     if (!strchr(relay_ip, '.'))
  386.       ipdelimeter = ':';
  387.     relay_ip_sub = strdup(relay_ip);
  388.     ptr = strrchr(relay_ip_sub, ipdelimeter);
  389.     if (ptr)
  390.       *ptr = '\0';
  391.  
  392.     sprintf(query,
  393.       "SELECT `id`, `block_expires` < UTC_TIMESTAMP() "
  394.       "FROM `greylisting_data` "
  395.       "WHERE `record_expires` > UTC_TIMESTAMP() "
  396.         "AND `relay_ip` LIKE '%s%c%%' "
  397.         "AND ( "
  398.           "( "
  399.             "`mail_from` = '%s' "
  400.             "AND `rcpt_to` = '%s' "
  401.           ") OR ( "
  402.             "`mail_from` IS NULL "
  403.             "AND `rcpt_to` IS NULL "
  404.           ") "
  405.         ") "
  406.       "ORDER BY `mail_from` ASC "
  407.       "LIMIT 1",
  408.       relay_ip_sub,
  409.       ipdelimeter,
  410.       mail_from_esc,
  411.       rcpt_to_esc);
  412.     free(relay_ip_sub);
  413.   }
  414.  
  415.   if (mysql_query_wrapper(mysql, query) ||
  416.       !(res = mysql_store_result(mysql)))
  417.   {
  418.     gllog(LOGLEVEL_ERROR, "greylisting: mysql: %s\n", mysql_error(mysql));
  419.     return RET_NOTFOUND;
  420.   }
  421.  
  422.   if ((row = mysql_fetch_row(res)))
  423.   {
  424.     if (atoi(row[1]))
  425.     {
  426.       sprintf(query,
  427.         "UPDATE `greylisting_data` "
  428.         "SET `mail_from` = NULL, `rcpt_to` = NULL, `record_expires` = UTC_TIMESTAMP() + INTERVAL %u DAY, `passed_count` = `passed_count` + 1 "
  429.         "WHERE `id` = '%s'",
  430.         record_expire_good, row[0]);
  431.       ret = RET_ACCEPT;
  432.       gllog(LOGLEVEL_INFO, "greylisting: %s (%s -> %s) exists (id=%s) - accepting\n", relay_ip, mail_from, rcpt_to, row[0]);
  433.     }
  434.     else
  435.     {
  436.       sprintf(query,
  437.         "UPDATE `greylisting_data` "
  438.         "SET `blocked_count` = `blocked_count` + 1 "
  439.         "WHERE `id` = '%s'",
  440.         row[0]);
  441.       ret = RET_TEMPREJECT;
  442.       gllog(LOGLEVEL_INFO, "greylisting: %s (%s -> %s) is blocked (id=%s) - temp. rejecting\n", relay_ip, mail_from, rcpt_to, row[0]);
  443.     }
  444.   }
  445.   else
  446.   {
  447.     sprintf(query,
  448.       "INSERT INTO `greylisting_data` "
  449.       "VALUES (0, '%s', '%s', '%s', UTC_TIMESTAMP() + INTERVAL %u MINUTE, UTC_TIMESTAMP() + INTERVAL %u MINUTE, 1, 0, 0, UTC_TIMESTAMP(), UTC_TIMESTAMP())",
  450.       relay_ip, mail_from_esc, rcpt_to_esc, block_expire, record_expire);
  451.     ret = RET_TEMPREJECT;
  452.     gllog(LOGLEVEL_INFO, "greylisting: %s (%s -> %s) doesn't exist. - temp. rejecting\n", relay_ip, mail_from, rcpt_to);
  453.   }
  454.   mysql_free_result(res);
  455.  
  456.   if (mysql_query_wrapper(mysql, query))
  457.   {
  458.     gllog(LOGLEVEL_ERROR, "greylisting: mysql: %s\n", mysql_error(mysql));
  459.     return RET_NOTFOUND;
  460.   }
  461.  
  462.   free(mail_from_esc);
  463.   free(rcpt_to_esc);
  464.   return ret;
  465. }
  466.  
  467. int main()
  468. {
  469.   int ret = 1;
  470.   int greylisted = 0;
  471.   MYSQL *mysql = NULL;
  472.  
  473.   /* load config */
  474.   if (ret && !load_config())
  475.     ret = 0;
  476.  
  477.   /* connect to mysql */
  478.   if (ret)
  479.   {
  480.     mysql_library_init(-1, NULL, NULL);
  481.     mysql = mysql_init(NULL);
  482.     if (!mysql_real_connect(mysql, mysql_host, mysql_user, mysql_pass, mysql_db, mysql_port, NULL, 0))
  483.     {
  484.       gllog(LOGLEVEL_FATAL, "greylisting: mysql: %s\n", mysql_error(mysql));
  485.       ret = 0;
  486.     }
  487.   }
  488.  
  489.   /* greylisting checks */
  490.   if (ret && !greylisted)
  491.   {
  492.     greylisted = check_listed(mysql);
  493.     if (greylisted == RET_NOTFOUND)
  494.       greylisted = check_greylisted(mysql);
  495.   }
  496.  
  497.   /* print smtp error code */
  498.   if (ret)
  499.   {
  500.     switch(greylisted)
  501.     {
  502.       case RET_REJECT:
  503.         printf(CMD_REJECT);
  504.         break;
  505.       case RET_TEMPREJECT:
  506.         printf(CMD_TEMPREJECT);
  507.         break;
  508.     }
  509.   }
  510.  
  511.   /* cleanup stuff */
  512.   gllog(LOGLEVEL_DEBUG, "greylisting: exiting\n");
  513.   if (mysql)
  514.     mysql_close(mysql);
  515.   mysql_library_end();
  516.   cleanup();
  517.   return !ret;
  518. }
  519.  
  520.