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blocklistd.c revision 1.8 
      1 /*	$NetBSD: blocklistd.c,v 1.8 2025/02/11 17:48:30 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 1.8 2025/02/11 17:48:30 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 	if (clock_gettime(CLOCK_REALTIME, &ts) == -1) {
    182 		(*lfun)(LOG_ERR, "clock_gettime failed (%m)");
    183 		return;
    184 	}
    185 
    186 	if ((bi = bl_recv(bl)) == NULL) {
    187 		(*lfun)(LOG_ERR, "no message (%m)");
    188 		return;
    189 	}
    190 
    191 	if (getremoteaddress(bi, &rss, &rsl) == -1)
    192 		goto out;
    193 
    194 	if (debug || bi->bi_msg[0]) {
    195 		sockaddr_snprintf(rbuf, sizeof(rbuf), "%a:%p", (void *)&rss);
    196 		(*lfun)(bi->bi_msg[0] ? LOG_INFO : LOG_DEBUG,
    197 		    "processing type=%d fd=%d remote=%s msg=%s uid=%lu gid=%lu",
    198 		    bi->bi_type, bi->bi_fd, rbuf,
    199 		    bi->bi_msg, (unsigned long)bi->bi_uid,
    200 		    (unsigned long)bi->bi_gid);
    201 	}
    202 
    203 	if (conf_find(bi->bi_fd, bi->bi_uid, &rss, &c) == NULL) {
    204 		(*lfun)(LOG_DEBUG, "no rule matched");
    205 		goto out;
    206 	}
    207 
    208 
    209 	if (state_get(state, &c, &dbi) == -1)
    210 		goto out;
    211 
    212 	if (debug) {
    213 		char b1[128], b2[128];
    214 		(*lfun)(LOG_DEBUG, "%s: initial db state for %s: count=%d/%d "
    215 		    "last=%s now=%s", __func__, rbuf, dbi.count, c.c_nfail,
    216 		    fmttime(b1, sizeof(b1), dbi.last),
    217 		    fmttime(b2, sizeof(b2), ts.tv_sec));
    218 	}
    219 
    220 	switch (bi->bi_type) {
    221 	case BL_ABUSE:
    222 		/*
    223 		 * If the application has signaled abusive behavior, set the
    224 		 * number of fails to be two less than the configured limit.
    225 		 * Fall through to the normal BL_ADD and BL_BADUSER processing,
    226 		 * which will increment the failure count to the threshhold, and
    227 		 * block the abusive address.
    228 		 */
    229 		if (c.c_nfail != -1)
    230 			dbi.count = c.c_nfail - 2;
    231 		/*FALLTHROUGH*/
    232 	case BL_ADD:
    233 		dbi.count++;		/* will become += 2 */
    234 		/*FALLTHROUGH*/
    235 	case BL_BADUSER:
    236 		dbi.count++;
    237 		dbi.last = ts.tv_sec;
    238 		if (c.c_nfail != -1 && dbi.count >= c.c_nfail) {
    239 			/*
    240 			 * No point in re-adding the rule.
    241 			 * It might exist already due to latency in processing
    242 			 * and removing the rule is the wrong thing to do as
    243 			 * it allows a window to attack again.
    244 			 */
    245 			if (dbi.id[0] == '\0') {
    246 				int res = run_change("add", &c,
    247 				    dbi.id, sizeof(dbi.id));
    248 				if (res == -1)
    249 					goto out;
    250 			}
    251 			sockaddr_snprintf(rbuf, sizeof(rbuf), "%a",
    252 			    (void *)&rss);
    253 			(*lfun)(LOG_INFO,
    254 			    "blocked %s/%d:%d for %d seconds",
    255 			    rbuf, c.c_lmask, c.c_port, c.c_duration);
    256 		}
    257 		break;
    258 	case BL_DELETE:
    259 		if (dbi.last == 0)
    260 			goto out;
    261 		dbi.count = 0;
    262 		dbi.last = 0;
    263 		break;
    264 	default:
    265 		(*lfun)(LOG_ERR, "unknown message %d", bi->bi_type);
    266 	}
    267 	state_put(state, &c, &dbi);
    268 
    269 out:
    270 	close(bi->bi_fd);
    271 
    272 	if (debug) {
    273 		char b1[128], b2[128];
    274 		(*lfun)(LOG_DEBUG, "%s: final db state for %s: count=%d/%d "
    275 		    "last=%s now=%s", __func__, rbuf, dbi.count, c.c_nfail,
    276 		    fmttime(b1, sizeof(b1), dbi.last),
    277 		    fmttime(b2, sizeof(b2), ts.tv_sec));
    278 	}
    279 }
    280 
    281 static void
    282 update_interfaces(void)
    283 {
    284 	struct ifaddrs *oifas, *nifas;
    285 
    286 	if (getifaddrs(&nifas) == -1)
    287 		return;
    288 
    289 	oifas = ifas;
    290 	ifas = nifas;
    291 
    292 	if (oifas)
    293 		freeifaddrs(oifas);
    294 }
    295 
    296 static void
    297 update(void)
    298 {
    299 	struct timespec ts;
    300 	struct conf c;
    301 	struct dbinfo dbi;
    302 	unsigned int f, n;
    303 	char buf[128];
    304 	void *ss = &c.c_ss;
    305 
    306 	if (clock_gettime(CLOCK_REALTIME, &ts) == -1) {
    307 		(*lfun)(LOG_ERR, "clock_gettime failed (%m)");
    308 		return;
    309 	}
    310 
    311 again:
    312 	for (n = 0, f = 1; state_iterate(state, &c, &dbi, f) == 1;
    313 	    f = 0, n++)
    314 	{
    315 		time_t when = c.c_duration + dbi.last;
    316 		if (debug > 1) {
    317 			char b1[64], b2[64];
    318 			sockaddr_snprintf(buf, sizeof(buf), "%a:%p", ss);
    319 			(*lfun)(LOG_DEBUG, "%s:[%u] %s count=%d duration=%d "
    320 			    "last=%s " "now=%s", __func__, n, buf, dbi.count,
    321 			    c.c_duration, fmttime(b1, sizeof(b1), dbi.last),
    322 			    fmttime(b2, sizeof(b2), ts.tv_sec));
    323 		}
    324 		if (c.c_duration == -1 || when >= ts.tv_sec)
    325 			continue;
    326 		if (dbi.id[0]) {
    327 			run_change("rem", &c, dbi.id, 0);
    328 			sockaddr_snprintf(buf, sizeof(buf), "%a", ss);
    329 			(*lfun)(LOG_INFO, "released %s/%d:%d after %d seconds",
    330 			    buf, c.c_lmask, c.c_port, c.c_duration);
    331 		}
    332 		state_del(state, &c);
    333 		goto again;
    334 	}
    335 }
    336 
    337 static void
    338 addfd(struct pollfd **pfdp, bl_t **blp, size_t *nfd, size_t *maxfd,
    339     const char *path)
    340 {
    341 	bl_t bl = bl_create(true, path, vflag ? vdlog : vsyslog_r);
    342 	if (bl == NULL || !bl_isconnected(bl))
    343 		exit(EXIT_FAILURE);
    344 	if (*nfd >= *maxfd) {
    345 		*maxfd += 10;
    346 		*blp = realloc(*blp, sizeof(**blp) * *maxfd);
    347 		if (*blp == NULL)
    348 			err(EXIT_FAILURE, "malloc");
    349 		*pfdp = realloc(*pfdp, sizeof(**pfdp) * *maxfd);
    350 		if (*pfdp == NULL)
    351 			err(EXIT_FAILURE, "malloc");
    352 	}
    353 
    354 	(*pfdp)[*nfd].fd = bl_getfd(bl);
    355 	(*pfdp)[*nfd].events = POLLIN;
    356 	(*blp)[*nfd] = bl;
    357 	*nfd += 1;
    358 }
    359 
    360 static void
    361 uniqueadd(struct conf ***listp, size_t *nlist, size_t *mlist, struct conf *c)
    362 {
    363 	struct conf **list = *listp;
    364 
    365 	if (c->c_name[0] == '\0')
    366 		return;
    367 	for (size_t i = 0; i < *nlist; i++) {
    368 		if (strcmp(list[i]->c_name, c->c_name) == 0)
    369 			return;
    370 	}
    371 	if (*nlist == *mlist) {
    372 		*mlist += 10;
    373 		void *p = realloc(*listp, *mlist * sizeof(*list));
    374 		if (p == NULL)
    375 			err(EXIT_FAILURE, "Can't allocate for rule list");
    376 		list = *listp = p;
    377 	}
    378 	list[(*nlist)++] = c;
    379 }
    380 
    381 static void
    382 rules_flush(void)
    383 {
    384 	struct conf **list;
    385 	size_t nlist, mlist;
    386 
    387 	list = NULL;
    388 	mlist = nlist = 0;
    389 	for (size_t i = 0; i < rconf.cs_n; i++)
    390 		uniqueadd(&list, &nlist, &mlist, &rconf.cs_c[i]);
    391 	for (size_t i = 0; i < lconf.cs_n; i++)
    392 		uniqueadd(&list, &nlist, &mlist, &lconf.cs_c[i]);
    393 
    394 	for (size_t i = 0; i < nlist; i++)
    395 		run_flush(list[i]);
    396 	free(list);
    397 }
    398 
    399 static void
    400 rules_restore(void)
    401 {
    402 	DB *db;
    403 	struct conf c;
    404 	struct dbinfo dbi;
    405 	unsigned int f;
    406 
    407 	db = state_open(dbfile, O_RDONLY, 0);
    408 	if (db == NULL) {
    409 		(*lfun)(LOG_ERR, "Can't open `%s' to restore state (%m)",
    410 			dbfile);
    411 		return;
    412 	}
    413 	for (f = 1; state_iterate(db, &c, &dbi, f) == 1; f = 0) {
    414 		if (dbi.id[0] == '\0')
    415 			continue;
    416 		(void)run_change("add", &c, dbi.id, sizeof(dbi.id));
    417 		state_put(state, &c, &dbi);
    418 	}
    419 	state_close(db);
    420 	state_sync(state);
    421 }
    422 
    423 int
    424 main(int argc, char *argv[])
    425 {
    426 	int c, tout, flags, flush, restore, ret;
    427 	const char *spath, **blsock;
    428 	size_t nblsock, maxblsock;
    429 
    430 	setprogname(argv[0]);
    431 
    432 	spath = NULL;
    433 	blsock = NULL;
    434 	maxblsock = nblsock = 0;
    435 	flush = 0;
    436 	restore = 0;
    437 	tout = 0;
    438 	flags = O_RDWR|O_EXCL|O_CLOEXEC;
    439 	while ((c = getopt(argc, argv, "C:c:D:dfP:rR:s:t:v")) != -1) {
    440 		switch (c) {
    441 		case 'C':
    442 			controlprog = optarg;
    443 			break;
    444 		case 'c':
    445 			configfile = optarg;
    446 			break;
    447 		case 'D':
    448 			dbfile = optarg;
    449 			break;
    450 		case 'd':
    451 			debug++;
    452 			break;
    453 		case 'f':
    454 			flush++;
    455 			break;
    456 		case 'P':
    457 			spath = optarg;
    458 			break;
    459 		case 'R':
    460 			rulename = optarg;
    461 			break;
    462 		case 'r':
    463 			restore++;
    464 			break;
    465 		case 's':
    466 			if (nblsock >= maxblsock) {
    467 				maxblsock += 10;
    468 				void *p = realloc(blsock,
    469 				    sizeof(*blsock) * maxblsock);
    470 				if (p == NULL)
    471 				    err(EXIT_FAILURE,
    472 					"Can't allocate memory for %zu sockets",
    473 					maxblsock);
    474 				blsock = p;
    475 			}
    476 			blsock[nblsock++] = optarg;
    477 			break;
    478 		case 't':
    479 			tout = atoi(optarg) * 1000;
    480 			break;
    481 		case 'v':
    482 			vflag++;
    483 			break;
    484 		default:
    485 			usage(c);
    486 		}
    487 	}
    488 
    489 	argc -= optind;
    490 	if (argc)
    491 		usage('?');
    492 
    493 	signal(SIGHUP, sighup);
    494 	signal(SIGINT, sigdone);
    495 	signal(SIGQUIT, sigdone);
    496 	signal(SIGTERM, sigdone);
    497 	signal(SIGUSR1, sigusr1);
    498 	signal(SIGUSR2, sigusr2);
    499 
    500 	openlog(getprogname(), LOG_PID, LOG_DAEMON);
    501 
    502 	if (debug) {
    503 		lfun = dlog;
    504 		if (tout == 0)
    505 			tout = 5000;
    506 	} else {
    507 		if (tout == 0)
    508 			tout = 15000;
    509 	}
    510 
    511 	update_interfaces();
    512 	conf_parse(configfile);
    513 	if (flush) {
    514 		rules_flush();
    515 		if (!restore)
    516 			flags |= O_TRUNC;
    517 	}
    518 
    519 	struct pollfd *pfd = NULL;
    520 	bl_t *bl = NULL;
    521 	size_t nfd = 0;
    522 	size_t maxfd = 0;
    523 
    524 	for (size_t i = 0; i < nblsock; i++)
    525 		addfd(&pfd, &bl, &nfd, &maxfd, blsock[i]);
    526 	free(blsock);
    527 
    528 	if (spath) {
    529 		FILE *fp = fopen(spath, "r");
    530 		char *line;
    531 		if (fp == NULL)
    532 			err(EXIT_FAILURE, "Can't open `%s'", spath);
    533 		for (; (line = fparseln(fp, NULL, NULL, NULL, 0)) != NULL;
    534 		    free(line))
    535 			addfd(&pfd, &bl, &nfd, &maxfd, line);
    536 		fclose(fp);
    537 	}
    538 	if (nfd == 0)
    539 		addfd(&pfd, &bl, &nfd, &maxfd, _PATH_BLSOCK);
    540 
    541 	state = state_open(dbfile, flags, 0600);
    542 	if (state == NULL)
    543 		state = state_open(dbfile,  flags | O_CREAT, 0600);
    544 	if (state == NULL)
    545 		return EXIT_FAILURE;
    546 
    547 	if (restore) {
    548 		if (!flush)
    549 			rules_flush();
    550 		rules_restore();
    551 	}
    552 
    553 	if (!debug) {
    554 		if (daemon(0, 0) == -1)
    555 			err(EXIT_FAILURE, "daemon failed");
    556 		if (pidfile(NULL) == -1)
    557 			err(EXIT_FAILURE, "Can't create pidfile");
    558 	}
    559 
    560 	for (size_t t = 0; !done; t++) {
    561 		if (readconf) {
    562 			readconf = 0;
    563 			conf_parse(configfile);
    564 		}
    565 		ret = poll(pfd, (nfds_t)nfd, tout);
    566 		if (debug)
    567 			(*lfun)(LOG_DEBUG, "received %d from poll()", ret);
    568 		switch (ret) {
    569 		case -1:
    570 			if (errno == EINTR)
    571 				continue;
    572 			(*lfun)(LOG_ERR, "poll (%m)");
    573 			return EXIT_FAILURE;
    574 		case 0:
    575 			state_sync(state);
    576 			break;
    577 		default:
    578 			for (size_t i = 0; i < nfd; i++)
    579 				if (pfd[i].revents & POLLIN)
    580 					process(bl[i]);
    581 		}
    582 		if (t % 100 == 0)
    583 			state_sync(state);
    584 		if (t % 10000 == 0)
    585 			update_interfaces();
    586 		update();
    587 	}
    588 	state_close(state);
    589 	return 0;
    590 }
    591