/*
* $Id$
*
- * Reject incoming SMTP messages containing strings that tell us that the
- * message is probably spam.
- *
+ * This module allows Citadel to use SpamAssassin to filter incoming messages
+ * arriving via SMTP. For more information on SpamAssassin, visit
+ * http://www.spamassassin.org (the SpamAssassin project is not in any way
+ * affiliated with the Citadel project).
*/
+#define SPAMASSASSIN_PORT "783"
#include "sysdep.h"
#include <stdlib.h>
#include <sys/wait.h>
#include <string.h>
#include <limits.h>
+#include <sys/socket.h>
#include "citadel.h"
#include "server.h"
-#include "sysdep_decls.h"
#include "citserver.h"
#include "support.h"
#include "config.h"
#include "control.h"
-#include "dynloader.h"
#include "room_ops.h"
#include "user_ops.h"
#include "policy.h"
#include "msgbase.h"
#include "tools.h"
#include "internet_addressing.h"
+#include "domain.h"
+#include "clientsocket.h"
-/* Scan a message for spam */
-int spam_filter(struct CtdlMessage *msg) {
- int spam_strings_found = 0;
- struct spamstrings_t *sptr;
- char *ptr;
+#include "ctdl_module.h"
- /* Bail out if there's no message text */
- if (msg->cm_fields['M'] == NULL) return(0);
- /* Scan! */
- ptr = msg->cm_fields['M'];
- while (ptr++[0] != 0) {
- for (sptr = spamstrings; sptr != NULL; sptr = sptr->next) {
- if (!strncasecmp(ptr, sptr->string,
- strlen(sptr->string))) {
- ++spam_strings_found;
- }
- }
+/*
+ * Connect to the SpamAssassin server and scan a message.
+ */
+int spam_assassin(struct CtdlMessage *msg) {
+ int sock = (-1);
+ char sahosts[SIZ];
+ int num_sahosts;
+ char buf[SIZ];
+ int is_spam = 0;
+ int sa;
+ char *msgtext;
+ size_t msglen;
+
+ /* For users who have authenticated to this server we never want to
+ * apply spam filtering, because presumably they're trustworthy.
+ */
+ if (CC->logged_in) return(0);
+
+ /* See if we have any SpamAssassin hosts configured */
+ num_sahosts = get_hosts(sahosts, "spamassassin");
+ if (num_sahosts < 1) return(0);
+
+ /* Try them one by one until we get a working one */
+ for (sa=0; sa<num_sahosts; ++sa) {
+ extract_token(buf, sahosts, sa, '|', sizeof buf);
+ lprintf(CTDL_INFO, "Connecting to SpamAssassin at <%s>\n", buf);
+ sock = sock_connect(buf, SPAMASSASSIN_PORT, "tcp");
+ if (sock >= 0) lprintf(CTDL_DEBUG, "Connected!\n");
+ }
+
+ if (sock < 0) {
+ /* If the service isn't running, just pass the mail
+ * through. Potentially throwing away mails isn't good.
+ */
+ return(0);
}
- if (spam_strings_found) {
+ /* Command */
+ lprintf(CTDL_DEBUG, "Transmitting command\n");
+ sprintf(buf, "CHECK SPAMC/1.2\r\n\r\n");
+ sock_write(sock, buf, strlen(buf));
+
+ /* Message */
+ CC->redirect_buffer = malloc(SIZ);
+ CC->redirect_len = 0;
+ CC->redirect_alloc = SIZ;
+ CtdlOutputPreLoadedMsg(msg, MT_RFC822, HEADERS_ALL, 0, 1);
+ msgtext = CC->redirect_buffer;
+ msglen = CC->redirect_len;
+ CC->redirect_buffer = NULL;
+ CC->redirect_len = 0;
+ CC->redirect_alloc = 0;
+
+ sock_write(sock, msgtext, msglen);
+ free(msgtext);
+
+ /* Close one end of the socket connection; this tells SpamAssassin
+ * that we're done.
+ */
+ sock_shutdown(sock, SHUT_WR);
+
+ /* Response */
+ lprintf(CTDL_DEBUG, "Awaiting response\n");
+ if (sock_gets(sock, buf) < 0) {
+ goto bail;
+ }
+ lprintf(CTDL_DEBUG, "<%s\n", buf);
+ if (strncasecmp(buf, "SPAMD", 5)) {
+ goto bail;
+ }
+ if (sock_gets(sock, buf) < 0) {
+ goto bail;
+ }
+ lprintf(CTDL_DEBUG, "<%s\n", buf);
+ if (!strncasecmp(buf, "Spam: True", 10)) {
+ is_spam = 1;
+ }
+
+ if (is_spam) {
if (msg->cm_fields['0'] != NULL) {
- phree(msg->cm_fields['0']);
+ free(msg->cm_fields['0']);
}
- msg->cm_fields['0'] = strdoop("Unsolicited spam rejected");
- return(spam_strings_found);
+ msg->cm_fields['0'] = strdup("5.7.1 message rejected by spam filter");
}
- return(0);
+bail: close(sock);
+ return(is_spam);
}
-char *Dynamic_Module_Init(void)
+CTDL_MODULE_INIT(spam)
{
- CtdlRegisterMessageHook(spam_filter, EVT_SMTPSCAN);
+ CtdlRegisterMessageHook(spam_assassin, EVT_SMTPSCAN);
+
+ /* return our Subversion id for the Log */
return "$Id$";
}