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  1. /*
  2.  * ProFTPD: mod_xclient
  3.  *
  4.  * Copyright (c) 2018 Manuel Mausz
  5.  *
  6.  * This program is free software; you can redistribute it and/or modify
  7.  * it under the terms of the GNU General Public License as published by
  8.  * the Free Software Foundation; either version 2 of the License, or
  9.  * (at your option) any later version.
  10.  *
  11.  * This program is distributed in the hope that it will be useful,
  12.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14.  * GNU General Public License for more details.
  15.  *
  16.  * You should have received a copy of the GNU General Public License
  17.  * along with this program; if not, write to the Free Software
  18.  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
  19.  */
  20.  
  21. #define MOD_XCLIENT_VERSION "mod_xclient/0.2.0"
  22.  
  23. #include "conf.h"
  24. #include "privs.h"
  25.  
  26. static const char *trace_channel = "xclient";
  27.  
  28. static int xclient_engine  = FALSE;
  29. static int xclient_rewrite = FALSE;
  30.  
  31. /* command handlers */
  32. MODRET xclient_xclient(cmd_rec *cmd)
  33. {
  34.   if (xclient_engine == FALSE)
  35.     return PR_DECLINED(cmd);
  36.  
  37.   if (cmd->argc < 2)
  38.     return PR_DECLINED(cmd);
  39.  
  40.   if (strncasecmp(cmd->argv[1], "XCLIENT", 7) == 0) {
  41.     if (cmd->argc < 4) {
  42.       pr_response_add_err(R_501, _("Invalid number of parameters"));
  43.       pr_cmd_set_errno(cmd, EINVAL);
  44.       errno = EINVAL;
  45.       return PR_ERROR(cmd);
  46.     }
  47.  
  48.     const pr_netaddr_t *remote_addr = NULL;
  49.     unsigned int remote_port = 0;
  50.  
  51.     for (unsigned int i = 2; i < cmd->argc; ++i) {
  52.       const char *param = cmd->argv[i];
  53.       pr_trace_msg(trace_channel, 5, "parsing parameter '%s'", param);
  54.       if (strncasecmp(param, "ADDR=", 5) == 0) {
  55.         remote_addr = pr_netaddr_get_addr2(session.pool,
  56.             param + 5, NULL, PR_NETADDR_GET_ADDR_FL_EXCL_DNS);
  57.         if (remote_addr == NULL) {
  58.           pr_response_add_err(R_501, _("%s: Invalid IP address provided"),
  59.               param + 5);
  60.           pr_cmd_set_errno(cmd, EINVAL);
  61.           errno = EINVAL;
  62.           return PR_ERROR(cmd);
  63.         }
  64.       }
  65.       else if (strncasecmp(param, "PORT=", 5) == 0) {
  66.         char *tmp = NULL;
  67.         remote_port = strtoul(param + 5, &tmp, 10);
  68.         if (tmp == NULL || *tmp != '\0' || remote_port <= 0 || remote_port > 65535) {
  69.           pr_response_add_err(R_501, _("%s: Invalid port provided"),
  70.               param + 5);
  71.           pr_cmd_set_errno(cmd, EINVAL);
  72.           errno = EINVAL;
  73.           return PR_ERROR(cmd);
  74.         }
  75.       }
  76.       else {
  77.         pr_response_add_err(R_500, _("'%s' not understood"), param);
  78.         pr_cmd_set_errno(cmd, EINVAL);
  79.         errno = EINVAL;
  80.         return PR_ERROR(cmd);
  81.       }
  82.     }
  83.  
  84.     if (remote_addr != NULL && remote_port > 0) {
  85.       const char *addr = pr_netaddr_get_ipstr(remote_addr);
  86.       (void) pr_table_remove(session.notes, "mod_xclient.addr", NULL);
  87.       if (pr_table_add_dup(session.notes, "mod_xclient.addr", addr, 0) < 0) {
  88.         pr_trace_msg(trace_channel, 3,
  89.             "error stashing 'mod_xclient.addr' in session.notes: %s",
  90.             strerror(errno));
  91.       }
  92.  
  93.       char port[6];
  94.       pr_snprintf(port, sizeof(port), "%u", remote_port);
  95.       (void) pr_table_remove(session.notes, "mod_xclient.port", NULL);
  96.       if (pr_table_add_dup(session.notes, "mod_xclient.port", port, 0) < 0) {
  97.         pr_trace_msg(trace_channel, 3,
  98.             "error stashing 'mod_xclient.port' in session.notes: %s",
  99.             strerror(errno));
  100.       }
  101.  
  102.       if (xclient_rewrite) {
  103.         session.c->remote_addr = remote_addr;
  104.         session.c->remote_port = remote_port;
  105.  
  106.         /* now perform reverse DNS lookups */
  107.         if (ServerUseReverseDNS) {
  108.           int reverse_dns = pr_netaddr_set_reverse_dns(ServerUseReverseDNS);
  109.           session.c->remote_name = pr_netaddr_get_dnsstr(session.c->remote_addr);
  110.           pr_netaddr_set_reverse_dns(reverse_dns);
  111.         }
  112.         else
  113.           session.c->remote_name = pr_netaddr_get_ipstr(session.c->remote_addr);
  114.  
  115.         pr_netaddr_set_sess_addrs();
  116.  
  117.         /* find the new class for this session */
  118.         session.conn_class = pr_class_match_addr(session.c->remote_addr);
  119.       }
  120.  
  121.       pr_log_debug(DEBUG0, MOD_XCLIENT_VERSION
  122.           ": stored%s client remote address: %s",
  123.           (xclient_rewrite) ? "+rewrote" : "", addr);
  124.       pr_trace_msg(trace_channel, 5, ": stored"
  125.           ": stored%s client remote address: %s",
  126.           (xclient_rewrite) ? "+rewrote" : "", addr);
  127.     }
  128.  
  129.     pr_response_add(R_200, _("SITE %s command successful"),
  130.       (char *)cmd->argv[1]);
  131.     return PR_HANDLED(cmd);
  132.   }
  133.  
  134.   return PR_DECLINED(cmd);
  135. }
  136.  
  137. /* configuration handlers */
  138. MODRET set_xclient_engine(cmd_rec *cmd)
  139. {
  140.   CHECK_ARGS(cmd, 1);
  141.   CHECK_CONF(cmd, CONF_ROOT|CONF_VIRTUAL|CONF_GLOBAL);
  142.  
  143.   int engine = get_boolean(cmd, 1);
  144.   if (engine == -1)
  145.     CONF_ERROR(cmd, "expected Boolean parameter");
  146.  
  147.   config_rec *c = add_config_param(cmd->argv[0], 1, NULL);
  148.   c->argv[0] = palloc(c->pool, sizeof(int));
  149.   *((int *)c->argv[0]) = engine;
  150.  
  151.   return PR_HANDLED(cmd);
  152. }
  153.  
  154. MODRET set_xclient_rewrite(cmd_rec *cmd)
  155. {
  156.   CHECK_ARGS(cmd, 1);
  157.   CHECK_CONF(cmd, CONF_ROOT|CONF_VIRTUAL|CONF_GLOBAL);
  158.  
  159.   int rewrite = get_boolean(cmd, 1);
  160.   if (rewrite == -1)
  161.     CONF_ERROR(cmd, "expected Boolean parameter");
  162.  
  163.   config_rec *c = add_config_param(cmd->argv[0], 1, NULL);
  164.   c->argv[0] = palloc(c->pool, sizeof(int));
  165.   *((int *)c->argv[0]) = rewrite;
  166.  
  167.   return PR_HANDLED(cmd);
  168. }
  169.  
  170. /* initialization routines */
  171. static int xclient_sess_init(void)
  172. {
  173.   config_rec *c = NULL;
  174.   c = find_config(main_server->conf, CONF_PARAM, "XClientEngine",  FALSE);
  175.   if (c != NULL)
  176.     xclient_engine = *((int *)c->argv[0]);
  177.  
  178.   c = find_config(main_server->conf, CONF_PARAM, "XClientRewrite", FALSE);
  179.   if (c != NULL)
  180.     xclient_rewrite = *((int *)c->argv[0]);
  181.  
  182.   return 0;
  183. }
  184.  
  185. /* module api tables */
  186. static conftable xclient_conftab[] =
  187. {
  188.   { "XClientEngine",  set_xclient_engine,  NULL },
  189.   { "XClientRewrite", set_xclient_rewrite, NULL },
  190.   { NULL }
  191. };
  192.  
  193. static cmdtable xclient_cmdtab[] =
  194. {
  195.   { CMD, C_SITE, G_NONE, xclient_xclient, FALSE, FALSE, CL_MISC },
  196.   { 0, NULL }
  197. };
  198.  
  199. module xclient_module =
  200. {
  201.   /* always NULL */
  202.   NULL, NULL,
  203.  
  204.   /* module api version 2.0 */
  205.   0x20,
  206.  
  207.   /* module name */
  208.   "xclient",
  209.  
  210.   /* module configuration handler table */
  211.   xclient_conftab,
  212.  
  213.   /* module command handler table */
  214.   xclient_cmdtab,
  215.  
  216.   /* module authentication handler table */
  217.   NULL,
  218.  
  219.   /* module initialization function */
  220.   NULL,
  221.  
  222.   /* module session initialization function */
  223.   xclient_sess_init,
  224.  
  225.   /* module version */
  226.   MOD_XCLIENT_VERSION
  227. };
  228.