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blocklistd.c revision 1.13 
      1 /*	$NetBSD: blocklistd.c,v 1.13 2025/12/15 15:44:36 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2015 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 #ifdef HAVE_CONFIG_H
     32 #include "config.h"
     33 #endif
     34 
     35 #ifdef HAVE_SYS_CDEFS_H
     36 #include <sys/cdefs.h>
     37 #endif
     38 __RCSID("$NetBSD: blocklistd.c,v 1.13 2025/12/15 15:44:36 christos Exp $");
     39 
     40 #include <sys/types.h>
     41 #include <sys/socket.h>
     42 #include <sys/queue.h>
     43 
     44 #ifdef HAVE_LIBUTIL_H
     45 #include <libutil.h>
     46 #endif
     47 #ifdef HAVE_UTIL_H
     48 #include <util.h>
     49 #endif
     50 #include <string.h>
     51 #include <signal.h>
     52 #include <netdb.h>
     53 #include <stdio.h>
     54 #include <stdbool.h>
     55 #include <string.h>
     56 #include <inttypes.h>
     57 #include <syslog.h>
     58 #include <ctype.h>
     59 #include <limits.h>
     60 #include <errno.h>
     61 #include <poll.h>
     62 #include <fcntl.h>
     63 #include <err.h>
     64 #include <stdlib.h>
     65 #include <unistd.h>
     66 #include <time.h>
     67 #include <ifaddrs.h>
     68 #include <netinet/in.h>
     69 
     70 #include "bl.h"
     71 #include "internal.h"
     72 #include "conf.h"
     73 #include "run.h"
     74 #include "state.h"
     75 #include "support.h"
     76 
     77 static const char *configfile = _PATH_BLCONF;
     78 static DB *state;
     79 static const char *dbfile = _PATH_BLSTATE;
     80 static sig_atomic_t readconf;
     81 static sig_atomic_t done;
     82 static int vflag;
     83 
     84 static void
     85 sigusr1(int n __unused)
     86 {
     87 	debug++;
     88 }
     89 
     90 static void
     91 sigusr2(int n __unused)
     92 {
     93 	debug--;
     94 }
     95 
     96 static void
     97 sighup(int n __unused)
     98 {
     99 	readconf++;
    100 }
    101 
    102 static void
    103 sigdone(int n __unused)
    104 {
    105 	done++;
    106 }
    107 
    108 static __dead void
    109 usage(int c)
    110 {
    111 	if (c != '?')
    112 		warnx("Unknown option `%c'", (char)c);
    113 	fprintf(stderr, "Usage: %s [-vdfr] [-c <config>] [-R <rulename>] "
    114 	    "[-P <sockpathsfile>] [-C <controlprog>] [-D <dbfile>] "
    115 	    "[-s <sockpath>] [-t <timeout>]\n", getprogname());
    116 	exit(EXIT_FAILURE);
    117 }
    118 
    119 static int
    120 getremoteaddress(bl_info_t *bi, struct sockaddr_storage *rss, socklen_t *rsl)
    121 {
    122 	*rsl = sizeof(*rss);
    123 	memset(rss, 0, *rsl);
    124 
    125 	if (getpeername(bi->bi_fd, (void *)rss, rsl) != -1)
    126 		return 0;
    127 
    128 	if (errno != ENOTCONN) {
    129 		(*lfun)(LOG_ERR, "getpeername failed (%m)");
    130 		return -1;
    131 	}
    132 
    133 	if (bi->bi_slen == 0) {
    134 		(*lfun)(LOG_ERR, "unconnected socket with no peer in message");
    135 		return -1;
    136 	}
    137 
    138 	switch (bi->bi_ss.ss_family) {
    139 	case AF_INET:
    140 		*rsl = sizeof(struct sockaddr_in);
    141 		break;
    142 	case AF_INET6:
    143 		*rsl = sizeof(struct sockaddr_in6);
    144 		break;
    145 	default:
    146 		(*lfun)(LOG_ERR, "bad client passed socket family %u",
    147 		    (unsigned)bi->bi_ss.ss_family);
    148 		return -1;
    149 	}
    150 
    151 	if (*rsl != bi->bi_slen) {
    152 		(*lfun)(LOG_ERR, "bad client passed socket length %u != %u",
    153 		    (unsigned)*rsl, (unsigned)bi->bi_slen);
    154 		return -1;
    155 	}
    156 
    157 	memcpy(rss, &bi->bi_ss, *rsl);
    158 
    159 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
    160 	if (*rsl != rss->ss_len) {
    161 		(*lfun)(LOG_ERR,
    162 		    "bad client passed socket internal length %u != %u",
    163 		    (unsigned)*rsl, (unsigned)rss->ss_len);
    164 		return -1;
    165 	}
    166 #endif
    167 	return 0;
    168 }
    169 
    170 static void
    171 process(bl_t bl)
    172 {
    173 	struct sockaddr_storage rss;
    174 	socklen_t rsl;
    175 	char rbuf[BUFSIZ];
    176 	bl_info_t *bi;
    177 	struct conf c;
    178 	struct dbinfo dbi;
    179 	struct timespec ts;
    180 
    181 	memset(&dbi, 0, sizeof(dbi));
    182 	memset(&c, 0, sizeof(c));
    183 	if (clock_gettime(CLOCK_REALTIME, &ts) == -1) {
    184 		(*lfun)(LOG_ERR, "clock_gettime failed (%m)");
    185 		return;
    186 	}
    187 
    188 	if ((bi = bl_recv(bl)) == NULL) {
    189 		(*lfun)(LOG_ERR, "no message (%m)");
    190 		return;
    191 	}
    192 
    193 	if (getremoteaddress(bi, &rss, &rsl) == -1)
    194 		goto out;
    195 
    196 	if (debug || bi->bi_msg[0]) {
    197 		sockaddr_snprintf(rbuf, sizeof(rbuf), "%a:%p", (void *)&rss);
    198 		(*lfun)(bi->bi_msg[0] ? LOG_INFO : LOG_DEBUG,
    199 		    "processing type=%d fd=%d remote=%s msg=%s uid=%lu gid=%lu",
    200 		    bi->bi_type, bi->bi_fd, rbuf,
    201 		    bi->bi_msg, (unsigned long)bi->bi_uid,
    202 		    (unsigned long)bi->bi_gid);
    203 	}
    204 
    205 	if (conf_find(bi->bi_fd, bi->bi_uid, &rss, &c) == NULL) {
    206 		(*lfun)(LOG_DEBUG, "no rule matched");
    207 		goto out;
    208 	}
    209 
    210 
    211 	if (state_get(state, &c, &dbi) == -1)
    212 		goto out;
    213 
    214 	if (debug) {
    215 		char b1[128], b2[128];
    216 		(*lfun)(LOG_DEBUG, "%s: initial db state for %s: count=%d/%d "
    217 		    "last=%s now=%s", __func__, rbuf, dbi.count, c.c_nfail,
    218 		    fmttime(b1, sizeof(b1), dbi.last),
    219 		    fmttime(b2, sizeof(b2), ts.tv_sec));
    220 	}
    221 
    222 	switch (bi->bi_type) {
    223 	case BL_ABUSE:
    224 		/*
    225 		 * If the application has signaled abusive behavior, set the
    226 		 * number of fails to be two less than the configured limit.
    227 		 * Fall through to the normal BL_ADD and BL_BADUSER processing,
    228 		 * which will increment the failure count to the threshold, and
    229 		 * block the abusive address.
    230 		 */
    231 		if (c.c_nfail != -1)
    232 			dbi.count = c.c_nfail - 2;
    233 		/*FALLTHROUGH*/
    234 	case BL_ADD:
    235 		dbi.count++;		/* will become += 2 */
    236 		/*FALLTHROUGH*/
    237 	case BL_BADUSER:
    238 		dbi.count++;
    239 		dbi.last = ts.tv_sec;
    240 		if (c.c_nfail != -1 && dbi.count >= c.c_nfail) {
    241 			/*
    242 			 * No point in re-adding the rule.
    243 			 * It might exist already due to latency in processing
    244 			 * and removing the rule is the wrong thing to do as
    245 			 * it allows a window to attack again.
    246 			 */
    247 			if (dbi.id[0] == '\0') {
    248 				int res = run_change("add", &c,
    249 				    dbi.id, sizeof(dbi.id));
    250 				if (res == -1)
    251 					goto out;
    252 			}
    253 			sockaddr_snprintf(rbuf, sizeof(rbuf), "%a",
    254 			    (void *)&rss);
    255 			(*lfun)(LOG_INFO,
    256 			    "blocked %s/%d:%d for %d seconds",
    257 			    rbuf, c.c_lmask, c.c_port, c.c_duration);
    258 		}
    259 		break;
    260 	case BL_DELETE:
    261 		if (dbi.last == 0)
    262 			goto out;
    263 		dbi.count = 0;
    264 		dbi.last = 0;
    265 		break;
    266 	default:
    267 		(*lfun)(LOG_ERR, "unknown message %d", bi->bi_type);
    268 	}
    269 	state_put(state, &c, &dbi);
    270 
    271 out:
    272 	close(bi->bi_fd);
    273 
    274 	if (debug) {
    275 		char b1[128], b2[128];
    276 		(*lfun)(LOG_DEBUG, "%s: final db state for %s: count=%d/%d "
    277 		    "last=%s now=%s", __func__, rbuf, dbi.count, c.c_nfail,
    278 		    fmttime(b1, sizeof(b1), dbi.last),
    279 		    fmttime(b2, sizeof(b2), ts.tv_sec));
    280 	}
    281 }
    282 
    283 static void
    284 update_interfaces(void)
    285 {
    286 	struct ifaddrs *oifas, *nifas;
    287 
    288 	if (getifaddrs(&nifas) == -1)
    289 		return;
    290 
    291 	oifas = ifas;
    292 	ifas = nifas;
    293 
    294 	if (oifas)
    295 		freeifaddrs(oifas);
    296 }
    297 
    298 static void
    299 update(void)
    300 {
    301 	struct timespec ts;
    302 	struct conf c;
    303 	struct dbinfo dbi;
    304 	unsigned int f, n;
    305 	char buf[128];
    306 	void *ss = &c.c_ss;
    307 
    308 	if (clock_gettime(CLOCK_REALTIME, &ts) == -1) {
    309 		(*lfun)(LOG_ERR, "clock_gettime failed (%m)");
    310 		return;
    311 	}
    312 
    313 again:
    314 	for (n = 0, f = 1; state_iterate(state, &c, &dbi, f) == 1;
    315 	    f = 0, n++)
    316 	{
    317 		time_t when = c.c_duration + dbi.last;
    318 		if (debug > 1) {
    319 			char b1[64], b2[64];
    320 			sockaddr_snprintf(buf, sizeof(buf), "%a:%p", ss);
    321 			(*lfun)(LOG_DEBUG, "%s:[%u] %s count=%d duration=%d "
    322 			    "last=%s " "now=%s", __func__, n, buf, dbi.count,
    323 			    c.c_duration, fmttime(b1, sizeof(b1), dbi.last),
    324 			    fmttime(b2, sizeof(b2), ts.tv_sec));
    325 		}
    326 		if (c.c_duration == -1 || when >= ts.tv_sec)
    327 			continue;
    328 		if (dbi.id[0]) {
    329 			run_change("rem", &c, dbi.id, 0);
    330 			sockaddr_snprintf(buf, sizeof(buf), "%a", ss);
    331 			(*lfun)(LOG_INFO, "released %s/%d:%d after %d seconds",
    332 			    buf, c.c_lmask, c.c_port, c.c_duration);
    333 		}
    334 		if (state_del(state, &c) == 0)
    335 			goto again;
    336 	}
    337 }
    338 
    339 static void
    340 addfd(struct pollfd **pfdp, bl_t **blp, size_t *nfd, size_t *maxfd,
    341     const char *path)
    342 {
    343 	bl_t bl = bl_create(true, path, vflag ? vdlog : vsyslog_r);
    344 	if (bl == NULL || !bl_isconnected(bl))
    345 		exit(EXIT_FAILURE);
    346 	if (*nfd >= *maxfd) {
    347 		*maxfd += 10;
    348 		*blp = realloc(*blp, sizeof(**blp) * *maxfd);
    349 		if (*blp == NULL)
    350 			err(EXIT_FAILURE, "malloc");
    351 		*pfdp = realloc(*pfdp, sizeof(**pfdp) * *maxfd);
    352 		if (*pfdp == NULL)
    353 			err(EXIT_FAILURE, "malloc");
    354 	}
    355 
    356 	(*pfdp)[*nfd].fd = bl_getfd(bl);
    357 	(*pfdp)[*nfd].events = POLLIN;
    358 	(*blp)[*nfd] = bl;
    359 	*nfd += 1;
    360 }
    361 
    362 static void
    363 uniqueadd(struct conf ***listp, size_t *nlist, size_t *mlist, struct conf *c)
    364 {
    365 	struct conf **list = *listp;
    366 
    367 	if (c->c_name[0] == '\0')
    368 		return;
    369 	for (size_t i = 0; i < *nlist; i++) {
    370 		if (strcmp(list[i]->c_name, c->c_name) == 0)
    371 			return;
    372 	}
    373 	if (*nlist == *mlist) {
    374 		*mlist += 10;
    375 		void *p = realloc(*listp, *mlist * sizeof(*list));
    376 		if (p == NULL)
    377 			err(EXIT_FAILURE, "Can't allocate for rule list");
    378 		list = *listp = p;
    379 	}
    380 	list[(*nlist)++] = c;
    381 }
    382 
    383 static void
    384 rules_flush(void)
    385 {
    386 	struct conf **list;
    387 	size_t nlist, mlist;
    388 
    389 	list = NULL;
    390 	mlist = nlist = 0;
    391 	for (size_t i = 0; i < rconf.cs_n; i++)
    392 		uniqueadd(&list, &nlist, &mlist, &rconf.cs_c[i]);
    393 	for (size_t i = 0; i < lconf.cs_n; i++)
    394 		uniqueadd(&list, &nlist, &mlist, &lconf.cs_c[i]);
    395 
    396 	for (size_t i = 0; i < nlist; i++)
    397 		run_flush(list[i]);
    398 	free(list);
    399 }
    400 
    401 static void
    402 rules_restore(void)
    403 {
    404 	DB *db;
    405 	struct conf c;
    406 	struct dbinfo dbi;
    407 	unsigned int f;
    408 
    409 	db = state_open(dbfile, O_RDONLY, 0);
    410 	if (db == NULL) {
    411 		(*lfun)(LOG_ERR, "Can't open `%s' to restore state (%m)",
    412 			dbfile);
    413 		return;
    414 	}
    415 	for (f = 1; state_iterate(db, &c, &dbi, f) == 1; f = 0) {
    416 		if (dbi.id[0] == '\0')
    417 			continue;
    418 		(void)run_change("add", &c, dbi.id, sizeof(dbi.id));
    419 		state_put(state, &c, &dbi);
    420 	}
    421 	state_close(db);
    422 	state_sync(state);
    423 }
    424 
    425 int
    426 main(int argc, char *argv[])
    427 {
    428 	int c, tout, flags, flush, restore, ret;
    429 	const char *spath, **blsock;
    430 	size_t nblsock, maxblsock;
    431 
    432 	setprogname(argv[0]);
    433 
    434 	spath = NULL;
    435 	blsock = NULL;
    436 	maxblsock = nblsock = 0;
    437 	flush = 0;
    438 	restore = 0;
    439 	tout = 0;
    440 	flags = O_RDWR|O_EXCL|O_CLOEXEC;
    441 	while ((c = getopt(argc, argv, "C:c:D:dfP:rR:s:t:v")) != -1) {
    442 		switch (c) {
    443 		case 'C':
    444 			controlprog = optarg;
    445 			break;
    446 		case 'c':
    447 			configfile = optarg;
    448 			break;
    449 		case 'D':
    450 			dbfile = optarg;
    451 			break;
    452 		case 'd':
    453 			debug++;
    454 			break;
    455 		case 'f':
    456 			flush++;
    457 			break;
    458 		case 'P':
    459 			spath = optarg;
    460 			break;
    461 		case 'R':
    462 			rulename = optarg;
    463 			break;
    464 		case 'r':
    465 			restore++;
    466 			break;
    467 		case 's':
    468 			if (nblsock >= maxblsock) {
    469 				maxblsock += 10;
    470 				void *p = realloc(blsock,
    471 				    sizeof(*blsock) * maxblsock);
    472 				if (p == NULL)
    473 				    err(EXIT_FAILURE,
    474 					"Can't allocate memory for %zu sockets",
    475 					maxblsock);
    476 				blsock = p;
    477 			}
    478 			blsock[nblsock++] = optarg;
    479 			break;
    480 		case 't':
    481 			tout = atoi(optarg) * 1000;
    482 			break;
    483 		case 'v':
    484 			vflag++;
    485 			break;
    486 		default:
    487 			usage(c);
    488 		}
    489 	}
    490 
    491 	argc -= optind;
    492 	if (argc)
    493 		usage('?');
    494 
    495 	signal(SIGHUP, sighup);
    496 	signal(SIGINT, sigdone);
    497 	signal(SIGQUIT, sigdone);
    498 	signal(SIGTERM, sigdone);
    499 	signal(SIGUSR1, sigusr1);
    500 	signal(SIGUSR2, sigusr2);
    501 
    502 	openlog(getprogname(), LOG_PID, LOG_DAEMON);
    503 
    504 	if (debug) {
    505 		lfun = dlog;
    506 		if (tout == 0)
    507 			tout = 5000;
    508 	} else {
    509 		if (tout == 0)
    510 			tout = 15000;
    511 	}
    512 
    513 	update_interfaces();
    514 	conf_parse(configfile);
    515 	if (flush) {
    516 		rules_flush();
    517 		if (!restore)
    518 			flags |= O_TRUNC;
    519 	}
    520 
    521 	struct pollfd *pfd = NULL;
    522 	bl_t *bl = NULL;
    523 	size_t nfd = 0;
    524 	size_t maxfd = 0;
    525 
    526 	for (size_t i = 0; i < nblsock; i++)
    527 		addfd(&pfd, &bl, &nfd, &maxfd, blsock[i]);
    528 	free(blsock);
    529 
    530 	if (spath) {
    531 		FILE *fp = fopen(spath, "r");
    532 		char *line;
    533 		if (fp == NULL)
    534 			err(EXIT_FAILURE, "Can't open `%s'", spath);
    535 		for (; (line = fparseln(fp, NULL, NULL, NULL, 0)) != NULL;
    536 		    free(line))
    537 			addfd(&pfd, &bl, &nfd, &maxfd, line);
    538 		fclose(fp);
    539 	}
    540 	if (nfd == 0)
    541 		addfd(&pfd, &bl, &nfd, &maxfd, _PATH_BLSOCK);
    542 
    543 	state = state_open(dbfile, flags, 0600);
    544 	if (state == NULL)
    545 		state = state_open(dbfile,  flags | O_CREAT, 0600);
    546 	if (state == NULL)
    547 		return EXIT_FAILURE;
    548 
    549 	if (restore) {
    550 		if (!flush)
    551 			rules_flush();
    552 		rules_restore();
    553 	}
    554 
    555 	if (!debug) {
    556 		if (daemon(0, 0) == -1)
    557 			err(EXIT_FAILURE, "daemon failed");
    558 		if (pidfile(NULL) == -1)
    559 			err(EXIT_FAILURE, "Can't create pidfile");
    560 	}
    561 
    562 	for (size_t t = 0; !done; t++) {
    563 		if (readconf) {
    564 			readconf = 0;
    565 			conf_parse(configfile);
    566 		}
    567 		ret = poll(pfd, (nfds_t)nfd, tout);
    568 		if (debug)
    569 			(*lfun)(LOG_DEBUG, "received %d from poll()", ret);
    570 		switch (ret) {
    571 		case -1:
    572 			if (errno == EINTR)
    573 				continue;
    574 			(*lfun)(LOG_ERR, "poll (%m)");
    575 			return EXIT_FAILURE;
    576 		case 0:
    577 			state_sync(state);
    578 			break;
    579 		default:
    580 			for (size_t i = 0; i < nfd; i++)
    581 				if (pfd[i].revents & POLLIN)
    582 					process(bl[i]);
    583 		}
    584 		if (t % 100 == 0)
    585 			state_sync(state);
    586 		if (t % 10000 == 0)
    587 			update_interfaces();
    588 		update();
    589 	}
    590 	state_close(state);
    591 	return 0;
    592 }
    593