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
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
|
/* $OpenBSD: spamlogd.c,v 1.14 2006/11/03 19:39:33 henning Exp $ */
/*
* Copyright (c) 2006 Henning Brauer <henning@openbsd.org>
* Copyright (c) 2006 Berk D. Demir.
* Copyright (c) 2004 Bob Beck.
* Copyright (c) 2001 Theo de Raadt.
* Copyright (c) 2001 Can Erkin Acar.
* All rights reserved
*
* 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.
*/
/* watch pf log for mail connections, update whitelist entries. */
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <net/if_pflog.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <net/pfvar.h>
#include <db.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <syslog.h>
#include <string.h>
#include <unistd.h>
#include <pcap.h>
#include "grey.h"
#define MIN_PFLOG_HDRLEN 45
#define PCAPSNAP 512
#define PCAPTIMO 500 /* ms */
#define PCAPOPTZ 1 /* optimize filter */
#define PCAPFSIZ 512 /* pcap filter string size */
u_int8_t flag_debug = 0;
u_int8_t flag_inbound = 0;
char *networkif = NULL;
char *pflogif = "pflog0";
char errbuf[PCAP_ERRBUF_SIZE];
pcap_t *hpcap = NULL;
struct syslog_data sdata = SYSLOG_DATA_INIT;
extern char *__progname;
void logmsg(int , const char *, ...);
void sighandler_close(int);
int init_pcap(void);
void logpkt_handler(u_char *, const struct pcap_pkthdr *, const u_char *);
int dbupdate(char *, char *);
void usage(void);
void
logmsg(int pri, const char *msg, ...)
{
va_list ap;
va_start(ap, msg);
if (flag_debug) {
vfprintf(stderr, msg, ap);
fprintf(stderr, "\n");
} else
vsyslog_r(pri, &sdata, msg, ap);
va_end(ap);
}
/* ARGSUSED */
void
sighandler_close(int signal)
{
if (hpcap != NULL)
pcap_breakloop(hpcap); /* sighdlr safe */
}
int
init_pcap(void)
{
struct bpf_program bpfp;
char filter[PCAPFSIZ] = "ip and port 25 and action pass "
"and tcp[13]&0x12=0x2";
if ((hpcap = pcap_open_live(pflogif, PCAPSNAP, 1, PCAPTIMO,
errbuf)) == NULL) {
logmsg(LOG_ERR, "Failed to initialize: %s", errbuf);
return (-1);
}
if (pcap_datalink(hpcap) != DLT_PFLOG) {
logmsg(LOG_ERR, "Invalid datalink type");
pcap_close(hpcap);
hpcap = NULL;
return (-1);
}
if (networkif != NULL) {
strlcat(filter, " and on ", PCAPFSIZ);
strlcat(filter, networkif, PCAPFSIZ);
}
if (pcap_compile(hpcap, &bpfp, filter, PCAPOPTZ, 0) == -1 ||
pcap_setfilter(hpcap, &bpfp) == -1) {
logmsg(LOG_ERR, "%s", pcap_geterr(hpcap));
return (-1);
}
pcap_freecode(&bpfp);
if (ioctl(pcap_fileno(hpcap), BIOCLOCK) < 0) {
logmsg(LOG_ERR, "BIOCLOCK: %s", strerror(errno));
return (-1);
}
return (0);
}
/* ARGSUSED */
void
logpkt_handler(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
{
sa_family_t af;
u_int8_t hdrlen;
u_int32_t caplen = h->caplen;
const struct ip *ip = NULL;
const struct pfloghdr *hdr;
char ipstraddr[40] = { '\0' };
hdr = (const struct pfloghdr *)sp;
if (hdr->length < MIN_PFLOG_HDRLEN) {
logmsg(LOG_WARNING, "invalid pflog header length (%u/%u). "
"packet dropped.", hdr->length, MIN_PFLOG_HDRLEN);
return;
}
hdrlen = BPF_WORDALIGN(hdr->length);
if (caplen < hdrlen) {
logmsg(LOG_WARNING, "pflog header larger than caplen (%u/%u). "
"packet dropped.", hdrlen, caplen);
return;
}
/* We're interested in passed packets */
if (hdr->action != PF_PASS)
return;
af = hdr->af;
if (af == AF_INET) {
ip = (const struct ip *)(sp + hdrlen);
if (hdr->dir == PF_IN)
inet_ntop(af, &ip->ip_src, ipstraddr,
sizeof(ipstraddr));
else if (hdr->dir == PF_OUT && !flag_inbound)
inet_ntop(af, &ip->ip_dst, ipstraddr,
sizeof(ipstraddr));
}
if (ipstraddr[0] != '\0') {
logmsg(LOG_DEBUG,"add %s to db", ipstraddr);
dbupdate(PATH_SPAMD_DB, ipstraddr);
}
}
int
dbupdate(char *dbname, char *ip)
{
BTREEINFO btreeinfo;
DBT dbk, dbd;
DB *db;
struct gdata gd;
time_t now;
int r;
struct in_addr ia;
now = time(NULL);
memset(&btreeinfo, 0, sizeof(btreeinfo));
db = dbopen(dbname, O_EXLOCK|O_RDWR, 0600, DB_BTREE, &btreeinfo);
if (db == NULL) {
logmsg(LOG_ERR, "Can not open db %s: %s", dbname,
strerror(errno));
return (-1);
}
if (inet_pton(AF_INET, ip, &ia) != 1) {
logmsg(LOG_NOTICE, "Invalid IP address %s", ip);
goto bad;
}
memset(&dbk, 0, sizeof(dbk));
dbk.size = strlen(ip);
dbk.data = ip;
memset(&dbd, 0, sizeof(dbd));
/* add or update whitelist entry */
r = db->get(db, &dbk, &dbd, 0);
if (r == -1) {
logmsg(LOG_NOTICE, "db->get failed (%m)");
goto bad;
}
if (r) {
/* new entry */
memset(&gd, 0, sizeof(gd));
gd.first = now;
gd.bcount = 1;
gd.pass = now;
gd.expire = now + WHITEEXP;
memset(&dbk, 0, sizeof(dbk));
dbk.size = strlen(ip);
dbk.data = ip;
memset(&dbd, 0, sizeof(dbd));
dbd.size = sizeof(gd);
dbd.data = &gd;
r = db->put(db, &dbk, &dbd, 0);
if (r) {
logmsg(LOG_NOTICE, "db->put failed (%m)");
goto bad;
}
} else {
if (dbd.size != sizeof(gd)) {
/* whatever this is, it doesn't belong */
db->del(db, &dbk, 0);
goto bad;
}
memcpy(&gd, dbd.data, sizeof(gd));
gd.pcount++;
gd.expire = now + WHITEEXP;
memset(&dbk, 0, sizeof(dbk));
dbk.size = strlen(ip);
dbk.data = ip;
memset(&dbd, 0, sizeof(dbd));
dbd.size = sizeof(gd);
dbd.data = &gd;
r = db->put(db, &dbk, &dbd, 0);
if (r) {
logmsg(LOG_NOTICE, "db->put failed (%m)");
goto bad;
}
}
db->close(db);
db = NULL;
return (0);
bad:
db->close(db);
db = NULL;
return (-1);
}
void
usage(void)
{
fprintf(stderr, "usage: %s [-DI] [-i interface] [-l pflog_interface]\n",
__progname);
exit(1);
}
int
main(int argc, char **argv)
{
int ch;
struct passwd *pw;
pcap_handler phandler = logpkt_handler;
while ((ch = getopt(argc, argv, "DIi:l:")) != -1) {
switch (ch) {
case 'D':
flag_debug = 1;
break;
case 'I':
flag_inbound = 1;
break;
case 'i':
networkif = optarg;
break;
case 'l':
pflogif = optarg;
break;
default:
usage();
/* NOTREACHED */
}
}
signal(SIGINT , sighandler_close);
signal(SIGQUIT, sighandler_close);
signal(SIGTERM, sighandler_close);
logmsg(LOG_DEBUG, "Listening on %s for %s %s", pflogif,
(networkif == NULL) ? "all interfaces." : networkif,
(flag_inbound) ? "Inbound direction only." : "");
if (init_pcap() == -1)
err(1, "couldn't initialize pcap");
/* privdrop */
pw = getpwnam("_spamd");
if (pw == NULL)
errx(1, "User '_spamd' not found! ");
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))
err(1, "failed to drop privs");
if (!flag_debug) {
if (daemon(0, 0) == -1)
err(1, "daemon");
tzset();
openlog_r("spamlogd", LOG_PID | LOG_NDELAY, LOG_DAEMON, &sdata);
}
pcap_loop(hpcap, -1, phandler, NULL);
logmsg(LOG_NOTICE, "exiting");
if (!flag_debug)
closelog_r(&sdata);
exit(0);
}
|