+++ /dev/null
-/* -*-c-*-
- *
- * $Id: qmail-checkspam.c,v 1.2 2004/04/08 01:36:26 mdw Exp $
- *
- * Filter messages for spam
- *
- * (c) 2003 Mark Wooding
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software Foundation,
- * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <ctype.h>
-#include <errno.h>
-#include <limits.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <sys/types.h>
-#include <sys/unistd.h>
-
-#include <syslog.h>
-
-#include <libspamc.h>
-
-/*----- Main code ---------------------------------------------------------*/
-
-static const char *strenv(const char *e, const char *d)
-{
- const char *p = getenv(e);
- if (!p) return (d);
- return (p);
-}
-
-static double dblenv(const char *e, double d)
-{
- const char *p = getenv(e);
- char *q;
- int err = errno;
- double f;
- if (!p) return (d);
- errno = 0;
- f = strtod(p, &q);
- if (errno) {
- syslog(LOG_ERR, "bad floating value `%s' for %s'; ignoring", p, e);
- return (d);
- }
- errno = err;
- return (f);
-}
-
-static int intenv(const char *e, int d)
-{
- const char *p = getenv(e);
- char *q;
- int err = errno;
- long l;
- if (!p) return (d);
- errno = 0;
- l = strtol(p, &q, 0);
- if (errno) return (d);
- errno = err;
- if (l < 0 || l > INT_MAX) {
- syslog(LOG_ERR, "bad integer value `%s' for `%s'; ignoring", p, e);
- return (d);
- }
- return ((int)l);
-}
-
-static int safewrite(int fd, const void *p, size_t sz)
-{
- const char *pp = p;
- ssize_t n;
-
- while (sz > 0) {
- n = write(fd, pp, sz);
- if (sz <= 0 && errno != EINTR && errno != EAGAIN)
- return (-1);
- sz -= n;
- pp += n;
- }
- return (0);
-}
-
-static int shovel(int from, int to, const char *what)
-{
- char buf[4096];
- ssize_t n;
-
- for (;;) {
- n = read(from, buf, sizeof(buf));
- if (n < 0 && errno != EINTR && errno != EAGAIN) {
- syslog(LOG_ERR, "failed to read %s: %m", what);
- return (-1);
- }
- else if (!n)
- return (0);
- if (safewrite(to, buf, n) < 0) {
- syslog(LOG_ERR, "failed to write %s: %m", what);
- return (-1);
- }
- }
-}
-
-#define ENVBUF 4096
-#define NRCPT 16
-struct envelope {
- unsigned f;
-#define EF_TRUNC 1u
- char buf[ENVBUF + 1];
- size_t n;
- const char *send;
- const char *rcpt[NRCPT];
- size_t nrcpt;
-};
-
-static int readenv(struct envelope *e)
-{
- ssize_t n;
- const char *p, *l;
-
- /* Read the raw envelope data. */
- e->n = 0;
- e->f = 0;
- while (e->n < ENVBUF) {
- n = read(1, e->buf + e->n, ENVBUF - e->n);
- if (n < 0 && errno != EINTR && errno != EAGAIN) {
- syslog(LOG_ERR, "failed to read envelope: %m");
- return (-1);
- }
- if (!n) break;
- e->n += n;
- }
- e->buf[e->n] = 0;
-
- /* Parse up the envelope data. */
- p = e->buf; l = p + e->n;
- e->nrcpt = 0;
- if (*p++ != 'F') {
- e->send = "<invalid>";
- syslog(LOG_ERR, "corrupt envelope (no sender marker)");
- return (-1);
- }
- e->send = p;
- for (;;) {
- if (p >= l) goto trunc;
- else if (!*p++) break;
- }
-
- for (;;) {
- if (p >= l) goto trunc;
- if (!*p) break;
- else if (*p++ != 'T') {
- syslog(LOG_ERR, "corrupt envelope (no recipient marker)");
- return (-1);
- }
- if (p >= l) goto trunc;
- if (e->nrcpt < NRCPT) e->rcpt[e->nrcpt++] = p;
- for (;;) {
- if (p >= l) goto trunc;
- else if (!*p++) break;
- }
- }
- return (0);
-
- /* Failed to reach the final terminator; maybe there's more. This isn't a
- * very bad situation.
- */
-trunc:
- e->f |= EF_TRUNC;
- return (0);
-}
-
-static void real(void)
-{
- const char *qmq =
- strenv("QMAIL_CHECKSPAM_QUEUE", "/var/qmail/bin/qmail-queue");
- execlp(qmq, qmq, (char *)0);
- syslog(LOG_ERR, "failed to exec %s: %m", qmq);
- exit(56);
-}
-
-static int split(int *fd_m, int *fd_e)
-{
- pid_t kid;
- int pm[2], pe[2];
-
- if (pipe(pm) || pipe(pe)) return (-1);
- if ((kid = fork()) < 0) return (-1);
- if (kid) {
- dup2(pm[0], 0); close(pm[0]); close(pm[1]);
- dup2(pe[0], 1); close(pe[0]); close(pe[1]);
- real();
- } else {
- close(pm[0]); *fd_m = pm[1];
- close(pe[0]); *fd_e = pe[1];
- }
- return (0);
-}
-
-static int writemsg(struct message *m, int fd_m, int shovelp)
-{
- if (message_write(fd_m, m) < 0) {
- syslog(LOG_ERR, "failed to write message body: %m");
- return (-1);
- }
- if (shovelp && shovel(0, fd_m, "message body"))
- return (-1);
- close(fd_m);
- return (0);
-}
-
-static int writeenv(struct envelope *e, int fd_e)
-{
- if (safewrite(fd_e, e->buf, e->n) < 0) {
- syslog(LOG_ERR, "failed to write envelope: %m");
- return (-1);
- }
- if ((e->f & EF_TRUNC) && shovel(1, fd_e, "envelope"))
- return (-1);
- close(fd_e);
- return (0);
-}
-
-static void logenv(struct envelope *e)
-{
- size_t i;
-
- syslog(LOG_NOTICE, "sender = %s", e->send);
- for (i = 0; i < e->nrcpt; i++)
- syslog(LOG_NOTICE, "recipient %lu = %s", (unsigned long)i, e->rcpt[i]);
-}
-
-int main(int argc, char *argv[])
-{
- struct sockaddr sa;
- struct message m;
- struct envelope e;
- int fd_m, fd_e;
- const char *p;
- double thresh;
- int rc, port;
-
- /* Set up logging output. */
- if ((p = strrchr(argv[0], '/')) == 0) p = argv[0]; else p++;
- openlog(p, LOG_PID, LOG_MAIL);
-
- /* Read configuration from the environment. */
- if (getenv("RELAYCLIENT")) real();
- m.max_len = intenv("QMAIL_CHECKSPAM_MAXLEN", 2 * 1024 * 1024);
- m.timeout = intenv("QMAIL_CHECKSPAM_TIMEOUT", 300);
-
- /* Slurp an initial chunk of the message. */
- rc = message_read(0, 0, &m);
-
- switch (rc) {
-
- case 0:
- /* We read the message body OK. Now try to slurp in the envelope and
- * write a useful message.
- */
- if (readenv(&e)) return (54);
- syslog(LOG_NOTICE, "scanning message");
- logenv(&e);
-
- /* Filter the message and see what happens. */
- p = strenv("QMAIL_CHECKSPAM_SPAMDHOST", "localhost");
- port = intenv("QMAIL_CHECKSPAM_SPAMDPORT", 783);
- if (lookup_host(p, port, &sa)) {
- syslog(LOG_ERR, "lookup failed for host `%s', port %d", p, port);
- return (56);
- }
- if (message_filter(&sa, "spamd", 0, &m)) {
- syslog(LOG_ERR, "filter failed unexpectedly");
- return (74);
- }
-
- /* Check the resulting score. */
- thresh = dblenv("QMAIL_CHECKSPAM_THRESH", m.threshold);
- if (m.score >= thresh) {
- syslog(LOG_NOTICE, "rejecting: score %g >= %g", m.score, thresh);
- return (31);
- }
- syslog(LOG_NOTICE, "accepting: score %g < %g", m.score, thresh);
-
- /* Send the remaining stuff on to the real server. */
- if (split(&fd_m, &fd_e)) return (56);
- if (writemsg(&m, fd_m, 0) || writeenv(&e, fd_e)) _exit(127);
- break;
-
- case EX_TOOBIG:
- /* Message was too big. We must pass it all on to the real server
- * before picking up the envelope.
- */
- syslog(LOG_NOTICE, "message too large for filtering");
- if (split(&fd_m, &fd_e)) return (56);
- if (writemsg(&m, fd_m, 1) || readenv(&e)) _exit(127);
- logenv(&e);
- if (writeenv(&e, fd_e)) _exit(127);
- break;
-
- default:
- syslog(LOG_ERR, "failed to read message (rc = %d): %m", rc);
- return (54);
- }
-
- return (0);
-}
-
-/*----- That's all, folks -------------------------------------------------*/
~mdw / misc / commitdiff