1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
|
/* $OpenBSD: mfa.c,v 1.49 2010/06/02 19:16:53 chl 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 <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"
void mfa_imsg(struct smtpd *, struct imsgev *, struct imsg *);
__dead void mfa_shutdown(void);
void mfa_sig_handler(int, short, void *);
void mfa_setup_events(struct smtpd *);
void mfa_disable_events(struct smtpd *);
void mfa_test_mail(struct smtpd *, struct message *);
void mfa_test_rcpt(struct smtpd *, struct message *);
int strip_source_route(char *, size_t);
struct rule *ruleset_match(struct smtpd *, struct path *, struct sockaddr_storage *);
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:
imsg_compose_event(env->sc_ievs[PROC_SMTP],
IMSG_MFA_MAIL, imsg->hdr.peerid, 0, -1, imsg->data,
imsg->hdr.len - sizeof imsg->hdr);
return;
case IMSG_LKA_RCPT:
imsg_compose_event(env->sc_ievs[PROC_SMTP],
IMSG_MFA_RCPT, imsg->hdr.peerid, 0, -1, imsg->data,
imsg->hdr.len - sizeof imsg->hdr);
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);
}
void
mfa_setup_events(struct smtpd *env)
{
}
void
mfa_disable_events(struct smtpd *env)
{
}
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));
mfa_setup_events(env);
if (event_dispatch() < 0)
fatal("event_dispatch");
mfa_shutdown();
return (0);
}
void
mfa_test_mail(struct smtpd *env, struct message *m)
{
int status;
if (strip_source_route(m->sender.user, sizeof(m->sender.user)))
goto refuse;
if (! valid_localpart(m->sender.user) ||
! valid_domainpart(m->sender.domain)) {
/*
* "MAIL FROM:<>" is the exception we allow.
*/
if (!(m->sender.user[0] == '\0' && m->sender.domain[0] == '\0'))
goto refuse;
}
/* Current policy is to allow all well-formed addresses. */
goto accept;
refuse:
status = S_MESSAGE_PERMFAILURE;
imsg_compose_event(env->sc_ievs[PROC_SMTP], IMSG_MFA_MAIL, m->id, 0, -1,
&status, sizeof status);
return;
accept:
imsg_compose_event(env->sc_ievs[PROC_LKA], IMSG_LKA_MAIL, 0,
0, -1, m, sizeof *m);
}
void
mfa_test_rcpt(struct smtpd *env, struct message *m)
{
int status;
m->recipient = m->session_rcpt;
strip_source_route(m->recipient.user, sizeof(m->recipient.user));
if (! valid_localpart(m->recipient.user) ||
! valid_domainpart(m->recipient.domain))
goto refuse;
if (m->flags & F_MESSAGE_AUTHENTICATED)
m->recipient.flags |= F_PATH_AUTHENTICATED;
imsg_compose_event(env->sc_ievs[PROC_LKA], IMSG_LKA_RCPT, 0, 0, -1,
m, sizeof *m);
return;
refuse:
status = S_MESSAGE_PERMFAILURE;
imsg_compose_event(env->sc_ievs[PROC_SMTP], IMSG_MFA_RCPT, m->id, 0, -1,
&status, sizeof status);
}
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;
}
|
