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/* $OpenBSD: mfa.c,v 1.55 2011/04/15 17:01:05 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 <event.h>
#include <imsg.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "smtpd.h"
#include "log.h"
void mfa_imsg(struct smtpd *, struct imsgev *, struct imsg *);
__dead void mfa_shutdown(void);
void mfa_sig_handler(int, short, void *);
void mfa_test_mail(struct smtpd *, struct message *);
void mfa_test_rcpt(struct smtpd *, struct message *);
void mfa_test_rcpt_resume(struct smtpd *, struct submit_status *);
int mfa_strip_source_route(char *, size_t);
void
mfa_imsg(struct smtpd *env, struct imsgev *iev, struct imsg *imsg)
{
if (iev->proc == PROC_SMTP) {
switch (imsg->hdr.type) {
case IMSG_MFA_MAIL:
mfa_test_mail(env, imsg->data);
return;
case IMSG_MFA_RCPT:
mfa_test_rcpt(env, imsg->data);
return;
}
}
if (iev->proc == PROC_LKA) {
switch (imsg->hdr.type) {
case IMSG_LKA_MAIL:
case IMSG_LKA_RCPT:
imsg_compose_event(env->sc_ievs[PROC_SMTP],
IMSG_MFA_MAIL, 0, 0, -1, imsg->data,
sizeof(struct submit_status));
return;
case IMSG_LKA_RULEMATCH:
mfa_test_rcpt_resume(env, imsg->data);
return;
}
}
if (iev->proc == PROC_PARENT) {
switch (imsg->hdr.type) {
case IMSG_CTL_VERBOSE:
log_verbose(*(int *)imsg->data);
return;
}
}
fatalx("mfa_imsg: unexpected imsg");
}
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_shutdown(void)
{
log_info("mail filter exiting");
_exit(0);
}
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, imsg_dispatch },
{ PROC_SMTP, imsg_dispatch },
{ PROC_LKA, imsg_dispatch },
{ PROC_CONTROL, imsg_dispatch }
};
switch (pid = fork()) {
case -1:
fatal("mfa: cannot fork");
case 0:
break;
default:
return (pid);
}
purge_config(env, PURGE_EVERYTHING);
pw = env->sc_pw;
if (chroot(pw->pw_dir) == -1)
fatal("mfa: chroot");
if (chdir("/") == -1)
fatal("mfa: chdir(\"/\")");
smtpd_process = PROC_MFA;
setproctitle("%s", env->sc_title[smtpd_process]);
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");
imsg_callback = mfa_imsg;
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, nitems(peers));
config_peers(env, peers, nitems(peers));
if (event_dispatch() < 0)
fatal("event_dispatch");
mfa_shutdown();
return (0);
}
void
mfa_test_mail(struct smtpd *env, struct message *m)
{
struct submit_status ss;
ss.id = m->id;
ss.code = 530;
ss.u.path = m->sender;
if (mfa_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_event(env->sc_ievs[PROC_SMTP], IMSG_MFA_MAIL, 0, 0, -1, &ss,
sizeof(ss));
return;
accept:
ss.code = 250;
imsg_compose_event(env->sc_ievs[PROC_LKA], IMSG_LKA_MAIL, 0,
0, -1, &ss, sizeof(ss));
}
void
mfa_test_rcpt(struct smtpd *env, struct message *m)
{
struct submit_status ss;
ss.id = m->session_id;
ss.code = 530;
ss.u.path = m->session_rcpt;
ss.ss = m->session_ss;
ss.msg = *m;
ss.msg.recipient = m->session_rcpt;
ss.flags = m->flags;
mfa_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 (ss.flags & F_MESSAGE_AUTHENTICATED)
ss.u.path.flags |= F_PATH_AUTHENTICATED;
imsg_compose_event(env->sc_ievs[PROC_LKA], IMSG_LKA_RULEMATCH, 0, 0, -1,
&ss, sizeof(ss));
return;
refuse:
imsg_compose_event(env->sc_ievs[PROC_SMTP], IMSG_MFA_RCPT, 0, 0, -1, &ss,
sizeof(ss));
}
void
mfa_test_rcpt_resume(struct smtpd *env, struct submit_status *ss) {
if (ss->code != 250) {
imsg_compose_event(env->sc_ievs[PROC_SMTP], IMSG_MFA_RCPT, 0, 0, -1, ss,
sizeof(*ss));
return;
}
ss->msg.recipient = ss->u.path;
ss->msg.expire = ss->msg.recipient.rule.r_qexpire;
imsg_compose_event(env->sc_ievs[PROC_LKA], IMSG_LKA_RCPT, 0, 0, -1,
ss, sizeof(*ss));
}
int
mfa_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;
}
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