2 15cacd92 2019-03-29 martijn * Copyright (c) 2019 Martijn van Duren <martijn@openbsd.org>
4 15cacd92 2019-03-29 martijn * Permission to use, copy, modify, and distribute this software for any
5 15cacd92 2019-03-29 martijn * purpose with or without fee is hereby granted, provided that the above
6 15cacd92 2019-03-29 martijn * copyright notice and this permission notice appear in all copies.
8 15cacd92 2019-03-29 martijn * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 15cacd92 2019-03-29 martijn * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 15cacd92 2019-03-29 martijn * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 15cacd92 2019-03-29 martijn * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 15cacd92 2019-03-29 martijn * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 15cacd92 2019-03-29 martijn * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 15cacd92 2019-03-29 martijn * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 aeda4d4e 2019-03-28 martijn #include <sys/types.h>
17 a248a3c1 2019-03-27 martijn #include <sys/socket.h>
19 2e3e5d5f 2019-03-29 martijn #include <arpa/inet.h>
20 a248a3c1 2019-03-27 martijn #include <errno.h>
21 aeda4d4e 2019-03-28 martijn #include <event.h>
22 a287838f 2019-03-31 martijn #include <inttypes.h>
23 a248a3c1 2019-03-27 martijn #include <netdb.h>
24 a248a3c1 2019-03-27 martijn #include <stdlib.h>
25 d4e702ee 2019-08-22 martijn #include <stdarg.h>
26 a248a3c1 2019-03-27 martijn #include <stdio.h>
27 a248a3c1 2019-03-27 martijn #include <string.h>
28 b633fa4c 2019-03-29 martijn #include <syslog.h>
29 a248a3c1 2019-03-27 martijn #include <unistd.h>
30 aeda4d4e 2019-03-28 martijn #include <asr.h>
32 5e62db7b 2019-08-22 martijn #include "opensmtpd.h"
34 aeda4d4e 2019-03-28 martijn struct dnsbl_session;
36 aeda4d4e 2019-03-28 martijn struct dnsbl_query {
37 aeda4d4e 2019-03-28 martijn struct event_asr *event;
38 a7f2d00f 2019-10-22 martijn int running;
39 aeda4d4e 2019-03-28 martijn int blacklist;
40 aeda4d4e 2019-03-28 martijn struct dnsbl_session *session;
43 aeda4d4e 2019-03-28 martijn struct dnsbl_session {
44 5468729e 2019-03-29 martijn int listed;
45 a287838f 2019-03-31 martijn int set_header;
46 a287838f 2019-03-31 martijn int logged_mark;
47 aeda4d4e 2019-03-28 martijn struct dnsbl_query *query;
48 5e62db7b 2019-08-22 martijn struct osmtpd_ctx *ctx;
51 1aa52bf5 2021-10-27 martijn static const char **blacklists = NULL;
52 1aa52bf5 2021-10-27 martijn static const char **printblacklists;
53 a248a3c1 2019-03-27 martijn static size_t nblacklists = 0;
54 5468729e 2019-03-29 martijn static int markspam = 0;
55 3b767c06 2019-08-22 martijn static int verbose = 0;
57 1aa52bf5 2021-10-27 martijn const char *dnsbl_printblacklist(const char *);
58 3ca25b7a 2025-05-19 martijn int dnsbl_connect(struct osmtpd_ctx *, const char *,
59 5e62db7b 2019-08-22 martijn struct sockaddr_storage *);
60 3ca25b7a 2025-05-19 martijn int dnsbl_begin(struct osmtpd_ctx *, uint32_t);
61 3ca25b7a 2025-05-19 martijn int dnsbl_dataline(struct osmtpd_ctx *, const char *);
62 aeda4d4e 2019-03-28 martijn void dnsbl_resolve(struct asr_result *, void *);
63 5468729e 2019-03-29 martijn void dnsbl_session_query_done(struct dnsbl_session *);
64 5e62db7b 2019-08-22 martijn void *dnsbl_session_new(struct osmtpd_ctx *);
65 5e62db7b 2019-08-22 martijn void dnsbl_session_free(struct osmtpd_ctx *, void *);
66 1aa52bf5 2021-10-27 martijn void usage(void);
69 a248a3c1 2019-03-27 martijn main(int argc, char *argv[])
72 5e62db7b 2019-08-22 martijn size_t i;
74 3b767c06 2019-08-22 martijn while ((ch = getopt(argc, argv, "mv")) != -1) {
75 a248a3c1 2019-03-27 martijn switch (ch) {
76 5468729e 2019-03-29 martijn case 'm':
77 5468729e 2019-03-29 martijn markspam = 1;
79 3b767c06 2019-08-22 martijn case 'v':
80 3b767c06 2019-08-22 martijn verbose = 1;
87 b633fa4c 2019-03-29 martijn if (pledge("stdio dns", NULL) == -1)
88 8b87eb2e 2019-08-22 martijn osmtpd_err(1, "pledge");
90 96a01110 2019-03-29 martijn if ((nblacklists = argc - optind) == 0)
91 8b87eb2e 2019-08-22 martijn osmtpd_errx(1, "No blacklist specified");
93 1aa52bf5 2021-10-27 martijn blacklists = calloc(nblacklists, sizeof(*blacklists));
94 1aa52bf5 2021-10-27 martijn printblacklists = calloc(nblacklists, sizeof(*printblacklists));
95 1aa52bf5 2021-10-27 martijn if (printblacklists == NULL || blacklists == NULL)
96 8b87eb2e 2019-08-22 martijn osmtpd_err(1, "malloc");
97 1aa52bf5 2021-10-27 martijn for (i = 0; i < nblacklists; i++) {
98 deafb383 2019-03-29 martijn blacklists[i] = argv[optind + i];
99 1aa52bf5 2021-10-27 martijn printblacklists[i] = dnsbl_printblacklist(argv[optind + i]);
102 5e62db7b 2019-08-22 martijn osmtpd_register_filter_connect(dnsbl_connect);
103 5e62db7b 2019-08-22 martijn osmtpd_local_session(dnsbl_session_new, dnsbl_session_free);
104 a287838f 2019-03-31 martijn if (markspam) {
105 5e62db7b 2019-08-22 martijn osmtpd_register_report_begin(1, dnsbl_begin);
106 5e62db7b 2019-08-22 martijn osmtpd_register_filter_dataline(dnsbl_dataline);
108 5e62db7b 2019-08-22 martijn osmtpd_run();
110 a248a3c1 2019-03-27 martijn return 0;
113 1aa52bf5 2021-10-27 martijn const char *
114 1aa52bf5 2021-10-27 martijn dnsbl_printblacklist(const char *blacklist)
116 1aa52bf5 2021-10-27 martijn /* All of abusix is paid and has a key in the first spot */
117 1aa52bf5 2021-10-27 martijn if (strcasestr(blacklist, ".mail.abusix.zone") != NULL)
118 1aa52bf5 2021-10-27 martijn return strchr(blacklist, '.') + 1;
119 1aa52bf5 2021-10-27 martijn /* XXX assume dq.spamhaus.net is paid and has a key in the first spot */
120 1aa52bf5 2021-10-27 martijn if (strcasestr(blacklist, ".dq.spamhaus.net") != NULL)
121 1aa52bf5 2021-10-27 martijn return strchr(blacklist, '.') + 1;
122 1aa52bf5 2021-10-27 martijn return blacklist;
126 5e62db7b 2019-08-22 martijn dnsbl_connect(struct osmtpd_ctx *ctx, const char *hostname,
127 5e62db7b 2019-08-22 martijn struct sockaddr_storage *ss)
129 5e62db7b 2019-08-22 martijn struct dnsbl_session *session = ctx->local_session;
130 5e62db7b 2019-08-22 martijn struct asr_query *aq;
131 a248a3c1 2019-03-27 martijn char query[255];
132 a248a3c1 2019-03-27 martijn u_char *addr;
133 5e62db7b 2019-08-22 martijn size_t i;
135 5e62db7b 2019-08-22 martijn if (ss->ss_family == AF_INET)
136 5e62db7b 2019-08-22 martijn addr = (u_char *)(&(((struct sockaddr_in *)ss)->sin_addr));
138 5e62db7b 2019-08-22 martijn addr = (u_char *)(&(((struct sockaddr_in6 *)ss)->sin6_addr));
139 a248a3c1 2019-03-27 martijn for (i = 0; i < nblacklists; i++) {
140 5e62db7b 2019-08-22 martijn if (ss->ss_family == AF_INET) {
141 a248a3c1 2019-03-27 martijn if (snprintf(query, sizeof(query), "%u.%u.%u.%u.%s",
142 a248a3c1 2019-03-27 martijn addr[3], addr[2], addr[1], addr[0],
143 5e62db7b 2019-08-22 martijn blacklists[i]) >= (int) sizeof(query))
144 4525b998 2019-08-22 martijn osmtpd_errx(1,
145 4525b998 2019-08-22 martijn "Can't create query, domain too long");
146 5e62db7b 2019-08-22 martijn } else if (ss->ss_family == AF_INET6) {
147 a248a3c1 2019-03-27 martijn if (snprintf(query, sizeof(query), "%hhx.%hhx.%hhx.%hhx"
148 a248a3c1 2019-03-27 martijn ".%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx"
149 a248a3c1 2019-03-27 martijn ".%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx"
150 a248a3c1 2019-03-27 martijn ".%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%s",
151 a248a3c1 2019-03-27 martijn (u_char) (addr[15] & 0xf), (u_char) (addr[15] >> 4),
152 a248a3c1 2019-03-27 martijn (u_char) (addr[14] & 0xf), (u_char) (addr[14] >> 4),
153 a248a3c1 2019-03-27 martijn (u_char) (addr[13] & 0xf), (u_char) (addr[13] >> 4),
154 a248a3c1 2019-03-27 martijn (u_char) (addr[12] & 0xf), (u_char) (addr[12] >> 4),
155 a248a3c1 2019-03-27 martijn (u_char) (addr[11] & 0xf), (u_char) (addr[11] >> 4),
156 a248a3c1 2019-03-27 martijn (u_char) (addr[10] & 0xf), (u_char) (addr[10] >> 4),
157 a248a3c1 2019-03-27 martijn (u_char) (addr[9] & 0xf), (u_char) (addr[9] >> 4),
158 a248a3c1 2019-03-27 martijn (u_char) (addr[8] & 0xf), (u_char) (addr[8] >> 4),
159 a248a3c1 2019-03-27 martijn (u_char) (addr[7] & 0xf), (u_char) (addr[8] >> 4),
160 a248a3c1 2019-03-27 martijn (u_char) (addr[6] & 0xf), (u_char) (addr[7] >> 4),
161 a248a3c1 2019-03-27 martijn (u_char) (addr[5] & 0xf), (u_char) (addr[5] >> 4),
162 a248a3c1 2019-03-27 martijn (u_char) (addr[4] & 0xf), (u_char) (addr[4] >> 4),
163 a248a3c1 2019-03-27 martijn (u_char) (addr[3] & 0xf), (u_char) (addr[3] >> 4),
164 a248a3c1 2019-03-27 martijn (u_char) (addr[2] & 0xf), (u_char) (addr[2] >> 4),
165 a248a3c1 2019-03-27 martijn (u_char) (addr[1] & 0xf), (u_char) (addr[1] >> 4),
166 a248a3c1 2019-03-27 martijn (u_char) (addr[0] & 0xf), (u_char) (addr[0] >> 4),
167 5e62db7b 2019-08-22 martijn blacklists[i]) >= (int) sizeof(query))
168 4525b998 2019-08-22 martijn osmtpd_errx(1,
169 4525b998 2019-08-22 martijn "Can't create query, domain too long");
171 8b87eb2e 2019-08-22 martijn osmtpd_errx(1, "Invalid address family received");
173 5e62db7b 2019-08-22 martijn aq = gethostbyname_async(query, NULL);
174 5e62db7b 2019-08-22 martijn session->query[i].event = event_asr_run(aq, dnsbl_resolve,
175 5e62db7b 2019-08-22 martijn &(session->query[i]));
176 aeda4d4e 2019-03-28 martijn session->query[i].blacklist = i;
177 aeda4d4e 2019-03-28 martijn session->query[i].session = session;
178 a7f2d00f 2019-10-22 martijn session->query[i].running = 1;
181 3ca25b7a 2025-05-19 martijn return 0;
185 aeda4d4e 2019-03-28 martijn dnsbl_resolve(struct asr_result *result, void *arg)
187 aeda4d4e 2019-03-28 martijn struct dnsbl_query *query = arg;
188 aeda4d4e 2019-03-28 martijn struct dnsbl_session *session = query->session;
189 5e62db7b 2019-08-22 martijn size_t i;
191 a7f2d00f 2019-10-22 martijn query->running = 0;
192 aeda4d4e 2019-03-28 martijn query->event = NULL;
193 aeda4d4e 2019-03-28 martijn if (result->ar_hostent != NULL) {
194 5468729e 2019-03-29 martijn if (!markspam) {
195 5e62db7b 2019-08-22 martijn osmtpd_filter_disconnect(session->ctx, "Listed at %s",
196 1aa52bf5 2021-10-27 martijn printblacklists[query->blacklist]);
197 d4e702ee 2019-08-22 martijn fprintf(stderr, "%016"PRIx64" listed at %s: rejected\n",
198 1aa52bf5 2021-10-27 martijn session->ctx->reqid,
199 1aa52bf5 2021-10-27 martijn printblacklists[query->blacklist]);
200 5468729e 2019-03-29 martijn } else {
201 5468729e 2019-03-29 martijn session->listed = query->blacklist;
202 5e62db7b 2019-08-22 martijn osmtpd_filter_proceed(session->ctx);
203 a287838f 2019-03-31 martijn /* Delay logging until we have a message */
205 a7f2d00f 2019-10-22 martijn dnsbl_session_query_done(session);
208 cf6af233 2019-03-28 martijn if (result->ar_h_errno != HOST_NOT_FOUND) {
209 5e62db7b 2019-08-22 martijn osmtpd_filter_disconnect(session->ctx, "DNS error on %s",
210 1aa52bf5 2021-10-27 martijn printblacklists[query->blacklist]);
211 a7f2d00f 2019-10-22 martijn dnsbl_session_query_done(session);
215 aeda4d4e 2019-03-28 martijn for (i = 0; i < nblacklists; i++) {
216 a7f2d00f 2019-10-22 martijn if (session->query[i].running)
219 5e62db7b 2019-08-22 martijn osmtpd_filter_proceed(session->ctx);
220 3b767c06 2019-08-22 martijn if (verbose)
221 d4e702ee 2019-08-22 martijn fprintf(stderr, "%016"PRIx64" not listed\n",
222 d4e702ee 2019-08-22 martijn session->ctx->reqid);
226 5e62db7b 2019-08-22 martijn dnsbl_begin(struct osmtpd_ctx *ctx, uint32_t msgid)
228 5e62db7b 2019-08-22 martijn struct dnsbl_session *session = ctx->local_session;
230 a287838f 2019-03-31 martijn if (session->listed != -1) {
231 a287838f 2019-03-31 martijn if (!session->logged_mark) {
232 d4e702ee 2019-08-22 martijn fprintf(stderr, "%016"PRIx64" listed at %s: Marking as "
233 1aa52bf5 2021-10-27 martijn "spam\n", ctx->reqid,
234 1aa52bf5 2021-10-27 martijn printblacklists[session->listed]);
235 a287838f 2019-03-31 martijn session->logged_mark = 1;
237 a287838f 2019-03-31 martijn session->set_header = 1;
240 3ca25b7a 2025-05-19 martijn return 0;
244 5e62db7b 2019-08-22 martijn dnsbl_dataline(struct osmtpd_ctx *ctx, const char *line)
246 5e62db7b 2019-08-22 martijn struct dnsbl_session *session = ctx->local_session;
248 a287838f 2019-03-31 martijn if (session->set_header) {
249 5e62db7b 2019-08-22 martijn osmtpd_filter_dataline(ctx, "X-Spam: yes");
250 5e62db7b 2019-08-22 martijn osmtpd_filter_dataline(ctx, "X-Spam-DNSBL: Listed at %s",
251 1aa52bf5 2021-10-27 martijn printblacklists[session->listed]);
252 a287838f 2019-03-31 martijn session->set_header = 0;
255 5e62db7b 2019-08-22 martijn osmtpd_filter_dataline(ctx, "%s", line);
257 3ca25b7a 2025-05-19 martijn return 0;
261 5468729e 2019-03-29 martijn dnsbl_session_query_done(struct dnsbl_session *session)
263 5e62db7b 2019-08-22 martijn size_t i;
265 aeda4d4e 2019-03-28 martijn for (i = 0; i < nblacklists; i++) {
266 a7f2d00f 2019-10-22 martijn if (session->query[i].running) {
267 aeda4d4e 2019-03-28 martijn event_asr_abort(session->query[i].event);
268 a7f2d00f 2019-10-22 martijn session->query[i].running = 0;
274 5e62db7b 2019-08-22 martijn dnsbl_session_new(struct osmtpd_ctx *ctx)
276 5e62db7b 2019-08-22 martijn struct dnsbl_session *session;
278 5e62db7b 2019-08-22 martijn if ((session = calloc(1, sizeof(*session))) == NULL)
279 8b87eb2e 2019-08-22 martijn osmtpd_err(1, "malloc");
280 5e62db7b 2019-08-22 martijn if ((session->query = calloc(nblacklists, sizeof(*(session->query))))
281 5e62db7b 2019-08-22 martijn == NULL)
282 8b87eb2e 2019-08-22 martijn osmtpd_err(1, "malloc");
283 5e62db7b 2019-08-22 martijn session->listed = -1;
284 5e62db7b 2019-08-22 martijn session->set_header = 0;
285 5e62db7b 2019-08-22 martijn session->logged_mark = 0;
286 5e62db7b 2019-08-22 martijn session->ctx = ctx;
288 5e62db7b 2019-08-22 martijn return session;
292 5e62db7b 2019-08-22 martijn dnsbl_session_free(struct osmtpd_ctx *ctx, void *data)
294 5e62db7b 2019-08-22 martijn struct dnsbl_session *session = data;
296 5468729e 2019-03-29 martijn dnsbl_session_query_done(session);
297 aeda4d4e 2019-03-28 martijn free(session->query);
298 aeda4d4e 2019-03-28 martijn free(session);
301 f8356fc3 2019-03-28 martijn __dead void
302 a248a3c1 2019-03-27 martijn usage(void)
304 ce077085 2019-11-14 martijn fprintf(stderr, "usage: filter-dnsbl [-m] blacklist [...]\n");
305 a248a3c1 2019-03-27 martijn exit(1);
