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|
/* $OpenBSD: mfa.c,v 1.17 2009/03/08 19:11:22 gilles Exp $ */
/*
* Copyright (c) 2008 Gilles Chehade <gilles@openbsd.org>
* Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/tree.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <event.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "smtpd.h"
__dead void mfa_shutdown(void);
void mfa_sig_handler(int, short, void *);
void mfa_dispatch_parent(int, short, void *);
void mfa_dispatch_smtp(int, short, void *);
void mfa_dispatch_lka(int, short, void *);
void mfa_dispatch_control(int, short, void *);
void mfa_setup_events(struct smtpd *);
void mfa_disable_events(struct smtpd *);
void mfa_timeout(int, short, void *);
void mfa_test_mail(struct smtpd *, struct message *, int);
void mfa_test_rcpt(struct smtpd *, struct message_recipient *, int);
int mfa_ruletest_rcpt(struct smtpd *, struct path *, struct sockaddr_storage *);
int mfa_check_source(struct map *, struct sockaddr_storage *);
int mfa_match_mask(struct sockaddr_storage *, struct netaddr *);
int strip_source_route(char *, size_t);
void
mfa_sig_handler(int sig, short event, void *p)
{
switch (sig) {
case SIGINT:
case SIGTERM:
mfa_shutdown();
break;
default:
fatalx("mfa_sig_handler: unexpected signal");
}
}
void
mfa_dispatch_parent(int sig, short event, void *p)
{
struct smtpd *env = p;
struct imsgbuf *ibuf;
struct imsg imsg;
ssize_t n;
ibuf = env->sc_ibufs[PROC_PARENT];
switch (event) {
case EV_READ:
if ((n = imsg_read(ibuf)) == -1)
fatal("imsg_read_error");
if (n == 0) {
/* this pipe is dead, so remove the event handler */
event_del(&ibuf->ev);
event_loopexit(NULL);
return;
}
break;
case EV_WRITE:
if (msgbuf_write(&ibuf->w) == -1)
fatal("msgbuf_write");
imsg_event_add(ibuf);
return;
default:
fatalx("unknown event");
}
for (;;) {
if ((n = imsg_get(ibuf, &imsg)) == -1)
fatal("parent_dispatch_mfa: imsg_read error");
if (n == 0)
break;
switch (imsg.hdr.type) {
default:
log_debug("parent_dispatch_mfa: unexpected imsg %d",
imsg.hdr.type);
break;
}
imsg_free(&imsg);
}
imsg_event_add(ibuf);
}
void
mfa_dispatch_smtp(int sig, short event, void *p)
{
struct smtpd *env = p;
struct imsgbuf *ibuf;
struct imsg imsg;
ssize_t n;
ibuf = env->sc_ibufs[PROC_SMTP];
switch (event) {
case EV_READ:
if ((n = imsg_read(ibuf)) == -1)
fatal("imsg_read_error");
if (n == 0) {
/* this pipe is dead, so remove the event handler */
event_del(&ibuf->ev);
event_loopexit(NULL);
return;
}
break;
case EV_WRITE:
if (msgbuf_write(&ibuf->w) == -1)
fatal("msgbuf_write");
imsg_event_add(ibuf);
return;
default:
fatalx("unknown event");
}
for (;;) {
if ((n = imsg_get(ibuf, &imsg)) == -1)
fatal("mfa_dispatch_smtp: imsg_read error");
if (n == 0)
break;
switch (imsg.hdr.type) {
case IMSG_MFA_MAIL:
mfa_test_mail(env, imsg.data, PROC_SMTP);
break;
case IMSG_MFA_RCPT:
mfa_test_rcpt(env, imsg.data, PROC_SMTP);
break;
default:
log_debug("mfa_dispatch_smtp: unexpected imsg %d",
imsg.hdr.type);
break;
}
imsg_free(&imsg);
}
imsg_event_add(ibuf);
}
void
mfa_dispatch_lka(int sig, short event, void *p)
{
struct smtpd *env = p;
struct imsgbuf *ibuf;
struct imsg imsg;
ssize_t n;
ibuf = env->sc_ibufs[PROC_LKA];
switch (event) {
case EV_READ:
if ((n = imsg_read(ibuf)) == -1)
fatal("imsg_read_error");
if (n == 0) {
/* this pipe is dead, so remove the event handler */
event_del(&ibuf->ev);
event_loopexit(NULL);
return;
}
break;
case EV_WRITE:
if (msgbuf_write(&ibuf->w) == -1)
fatal("msgbuf_write");
imsg_event_add(ibuf);
return;
default:
fatalx("unknown event");
}
for (;;) {
if ((n = imsg_get(ibuf, &imsg)) == -1)
fatal("mfa_dispatch_lka: imsg_read error");
if (n == 0)
break;
switch (imsg.hdr.type) {
case IMSG_LKA_MAIL: {
struct submit_status *ss;
ss = imsg.data;
imsg_compose(env->sc_ibufs[PROC_SMTP], IMSG_MFA_MAIL,
0, 0, -1, ss, sizeof(*ss));
break;
}
case IMSG_LKA_RCPT: {
struct submit_status *ss;
ss = imsg.data;
if (ss->msg.flags & F_MESSAGE_ENQUEUED)
imsg_compose(env->sc_ibufs[PROC_CONTROL], IMSG_MFA_RCPT,
0, 0, -1, ss, sizeof(*ss));
else
imsg_compose(env->sc_ibufs[PROC_SMTP], IMSG_MFA_RCPT,
0, 0, -1, ss, sizeof(*ss));
break;
}
default:
log_debug("mfa_dispatch_lka: unexpected imsg %d",
imsg.hdr.type);
break;
}
imsg_free(&imsg);
}
imsg_event_add(ibuf);
}
void
mfa_dispatch_control(int sig, short event, void *p)
{
struct smtpd *env = p;
struct imsgbuf *ibuf;
struct imsg imsg;
ssize_t n;
ibuf = env->sc_ibufs[PROC_CONTROL];
switch (event) {
case EV_READ:
if ((n = imsg_read(ibuf)) == -1)
fatal("imsg_read_error");
if (n == 0) {
/* this pipe is dead, so remove the event handler */
event_del(&ibuf->ev);
event_loopexit(NULL);
return;
}
break;
case EV_WRITE:
if (msgbuf_write(&ibuf->w) == -1)
fatal("msgbuf_write");
imsg_event_add(ibuf);
return;
default:
fatalx("unknown event");
}
for (;;) {
if ((n = imsg_get(ibuf, &imsg)) == -1)
fatal("mfa_dispatch_smtp: imsg_read error");
if (n == 0)
break;
switch (imsg.hdr.type) {
case IMSG_MFA_RCPT:
mfa_test_rcpt(env, imsg.data, PROC_CONTROL);
break;
default:
log_debug("mfa_dispatch_smtp: unexpected imsg %d",
imsg.hdr.type);
break;
}
imsg_free(&imsg);
}
imsg_event_add(ibuf);
}
void
mfa_shutdown(void)
{
log_info("mail filter exiting");
_exit(0);
}
void
mfa_setup_events(struct smtpd *env)
{
struct timeval tv;
evtimer_set(&env->sc_ev, mfa_timeout, env);
tv.tv_sec = 3;
tv.tv_usec = 0;
evtimer_add(&env->sc_ev, &tv);
}
void
mfa_disable_events(struct smtpd *env)
{
evtimer_del(&env->sc_ev);
}
void
mfa_timeout(int fd, short event, void *p)
{
struct smtpd *env = p;
struct timeval tv;
tv.tv_sec = 3;
tv.tv_usec = 0;
evtimer_add(&env->sc_ev, &tv);
}
pid_t
mfa(struct smtpd *env)
{
pid_t pid;
struct passwd *pw;
struct event ev_sigint;
struct event ev_sigterm;
struct peer peers[] = {
{ PROC_PARENT, mfa_dispatch_parent },
{ PROC_SMTP, mfa_dispatch_smtp },
{ PROC_LKA, mfa_dispatch_lka },
{ PROC_CONTROL, mfa_dispatch_control},
};
switch (pid = fork()) {
case -1:
fatal("mfa: cannot fork");
case 0:
break;
default:
return (pid);
}
// purge_config(env, PURGE_EVERYTHING);
pw = env->sc_pw;
#ifndef DEBUG
if (chroot(pw->pw_dir) == -1)
fatal("mfa: chroot");
if (chdir("/") == -1)
fatal("mfa: chdir(\"/\")");
#else
#warning disabling privilege revocation and chroot in DEBUG MODE
#endif
setproctitle("mail filter agent");
smtpd_process = PROC_MFA;
#ifndef DEBUG
if (setgroups(1, &pw->pw_gid) ||
setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
fatal("mfa: cannot drop privileges");
#endif
event_init();
signal_set(&ev_sigint, SIGINT, mfa_sig_handler, env);
signal_set(&ev_sigterm, SIGTERM, mfa_sig_handler, env);
signal_add(&ev_sigint, NULL);
signal_add(&ev_sigterm, NULL);
signal(SIGPIPE, SIG_IGN);
signal(SIGHUP, SIG_IGN);
config_pipes(env, peers, 4);
config_peers(env, peers, 4);
mfa_setup_events(env);
event_dispatch();
mfa_shutdown();
return (0);
}
int
msg_cmp(struct message *m1, struct message *m2)
{
/*
* do not return u_int64_t's
*/
if (m1->id - m2->id > 0)
return (1);
else if (m1->id - m2->id < 0)
return (-1);
else
return (0);
}
void
mfa_test_mail(struct smtpd *env, struct message *m, int sender)
{
struct submit_status ss;
ss.id = m->id;
ss.code = 530;
ss.u.path = m->sender;
if (strip_source_route(ss.u.path.user, sizeof(ss.u.path.user)))
goto refuse;
if (! valid_localpart(ss.u.path.user) ||
! valid_domainpart(ss.u.path.domain)) {
/*
* "MAIL FROM:<>" is the exception we allow.
*/
if (!(ss.u.path.user[0] == '\0' && ss.u.path.domain[0] == '\0'))
goto refuse;
}
/* Current policy is to allow all well-formed addresses. */
goto accept;
refuse:
imsg_compose(env->sc_ibufs[sender], IMSG_MFA_MAIL, 0, 0, -1, &ss,
sizeof(ss));
return;
accept:
ss.code = 250;
imsg_compose(env->sc_ibufs[PROC_LKA], IMSG_LKA_MAIL, 0,
0, -1, &ss, sizeof(ss));
}
void
mfa_test_rcpt(struct smtpd *env, struct message_recipient *mr, int sender)
{
struct submit_status ss;
ss.id = mr->id;
ss.code = 530;
ss.u.path = mr->path;
ss.ss = mr->ss;
ss.msg = mr->msg;
ss.flags = mr->flags;
strip_source_route(ss.u.path.user, sizeof(ss.u.path.user));
if (! valid_localpart(ss.u.path.user) ||
! valid_domainpart(ss.u.path.domain))
goto refuse;
if (sender == PROC_SMTP && (ss.flags & F_MESSAGE_AUTHENTICATED))
goto accept;
if (mfa_ruletest_rcpt(env, &ss.u.path, &ss.ss))
goto accept;
refuse:
imsg_compose(env->sc_ibufs[sender], IMSG_MFA_RCPT, 0, 0, -1, &ss,
sizeof(ss));
return;
accept:
ss.code = 250;
imsg_compose(env->sc_ibufs[PROC_LKA], IMSG_LKA_RCPT, 0, 0, -1,
&ss, sizeof(ss));
}
int
mfa_ruletest_rcpt(struct smtpd *env, struct path *path, struct sockaddr_storage *ss)
{
struct rule *r;
struct cond *cond;
struct map *map;
struct mapel *me;
TAILQ_FOREACH(r, env->sc_rules, r_entry) {
if (! mfa_check_source(r->r_sources, ss))
continue;
TAILQ_FOREACH(cond, &r->r_conditions, c_entry) {
if (cond->c_type == C_ALL) {
path->rule = *r;
return 1;
}
if (cond->c_type == C_DOM) {
cond->c_match = map_find(env, cond->c_map);
if (cond->c_match == NULL)
fatal("mfa failed to lookup map.");
map = cond->c_match;
TAILQ_FOREACH(me, &map->m_contents, me_entry) {
log_debug("matching: %s to %s",
path->domain, me->me_key.med_string);
if (hostname_match(path->domain, me->me_key.med_string)) {
path->rule = *r;
return 1;
}
}
}
}
}
return 0;
}
int
mfa_check_source(struct map *map, struct sockaddr_storage *ss)
{
struct mapel *me;
if (ss == NULL) {
/* This happens when caller is part of an internal
* lookup (ie: alias resolved to a remote address)
*/
return 1;
}
TAILQ_FOREACH(me, &map->m_contents, me_entry) {
if (ss->ss_family != me->me_key.med_addr.ss.ss_family)
continue;
if (ss->ss_len == me->me_key.med_addr.ss.ss_len)
continue;
if (mfa_match_mask(ss, &me->me_key.med_addr))
return 1;
}
return 0;
}
int
mfa_match_mask(struct sockaddr_storage *ss, struct netaddr *ssmask)
{
if (ss->ss_family == AF_INET) {
struct sockaddr_in *ssin = (struct sockaddr_in *)ss;
struct sockaddr_in *ssinmask = (struct sockaddr_in *)&ssmask->ss;
if ((ssin->sin_addr.s_addr & ssinmask->sin_addr.s_addr) ==
ssinmask->sin_addr.s_addr)
return (1);
return (0);
}
if (ss->ss_family == AF_INET6) {
struct in6_addr *in;
struct in6_addr *inmask;
struct in6_addr mask;
int i;
bzero(&mask, sizeof(mask));
for (i = 0; i < (128 - ssmask->bits) / 8; i++)
mask.s6_addr[i] = 0xff;
i = ssmask->bits % 8;
if (i)
mask.s6_addr[ssmask->bits / 8] = 0xff00 >> i;
in = &((struct sockaddr_in6 *)ss)->sin6_addr;
inmask = &((struct sockaddr_in6 *)&ssmask->ss)->sin6_addr;
for (i = 0; i < 16; i++) {
if ((in->s6_addr[i] & mask.s6_addr[i]) !=
inmask->s6_addr[i])
return (0);
}
return (1);
}
return (0);
}
int
strip_source_route(char *buf, size_t len)
{
char *p;
p = strchr(buf, ':');
if (p != NULL) {
p++;
memmove(buf, p, strlen(p) + 1);
return 1;
}
return 0;
}
|