xref: /freebsd/sys/netlink/netlink_message_parser.c (revision ebacd8013fe5f7fdf9f6a5b286f6680dd2891036)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 #include "opt_inet.h"
31 #include "opt_inet6.h"
32 #include <sys/types.h>
33 #include <sys/malloc.h>
34 #include <sys/rmlock.h>
35 #include <sys/socket.h>
36 
37 #include <machine/stdarg.h>
38 
39 #include <net/if.h>
40 #include <net/route.h>
41 #include <net/route/nhop.h>
42 
43 #include <net/route/route_ctl.h>
44 #include <netinet/in.h>
45 #include <netlink/netlink.h>
46 #include <netlink/netlink_ctl.h>
47 #include <netlink/netlink_var.h>
48 #include <netlink/netlink_route.h>
49 
50 #define	DEBUG_MOD_NAME	nl_parser
51 #define	DEBUG_MAX_LEVEL	LOG_DEBUG3
52 #include <netlink/netlink_debug.h>
53 _DECLARE_DEBUG(LOG_DEBUG);
54 
55 bool
56 nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...)
57 {
58 	va_list ap;
59 
60 	if (npt->err_msg != NULL)
61 		return (false);
62 	char *buf = npt_alloc(npt, NL_MAX_ERROR_BUF);
63 	if (buf == NULL)
64 		return (false);
65 	va_start(ap, fmt);
66 	vsnprintf(buf, NL_MAX_ERROR_BUF, fmt, ap);
67 	va_end(ap);
68 
69 	npt->err_msg = buf;
70 	return (true);
71 }
72 
73 bool
74 nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off)
75 {
76 	if (npt->err_off != 0)
77 		return (false);
78 	npt->err_off = off;
79 	return (true);
80 }
81 
82 void
83 nlmsg_report_cookie(struct nl_pstate *npt, struct nlattr *nla)
84 {
85 	MPASS(nla->nla_type == NLMSGERR_ATTR_COOKIE);
86 	MPASS(nla->nla_len >= sizeof(struct nlattr));
87 	npt->cookie = nla;
88 }
89 
90 void
91 nlmsg_report_cookie_u32(struct nl_pstate *npt, uint32_t val)
92 {
93 	struct nlattr *nla = npt_alloc(npt, sizeof(*nla) + sizeof(uint32_t));
94 
95 	nla->nla_type = NLMSGERR_ATTR_COOKIE;
96 	nla->nla_len = sizeof(*nla) + sizeof(uint32_t);
97 	memcpy(nla + 1, &val, sizeof(uint32_t));
98 	nlmsg_report_cookie(npt, nla);
99 }
100 
101 static const struct nlattr_parser *
102 search_states(const struct nlattr_parser *ps, int pslen, int key)
103 {
104 	int left_i = 0, right_i = pslen - 1;
105 
106 	if (key < ps[0].type || key > ps[pslen - 1].type)
107 		return (NULL);
108 
109 	while (left_i + 1 < right_i) {
110 		int mid_i = (left_i + right_i) / 2;
111 		if (key < ps[mid_i].type)
112 			right_i = mid_i;
113 		else if (key > ps[mid_i].type)
114 			left_i = mid_i + 1;
115 		else
116 			return (&ps[mid_i]);
117 	}
118 	if (ps[left_i].type == key)
119 		return (&ps[left_i]);
120 	else if (ps[right_i].type == key)
121 		return (&ps[right_i]);
122 	return (NULL);
123 }
124 
125 int
126 nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser *ps, int pslen,
127     struct nl_pstate *npt, void *target)
128 {
129 	struct nlattr *nla = NULL;
130 	int error = 0;
131 
132 	NL_LOG(LOG_DEBUG3, "parse %p remaining_len %d", nla_head, len);
133 	int orig_len = len;
134 	NLA_FOREACH(nla, nla_head, len) {
135 		NL_LOG(LOG_DEBUG3, ">> parsing %p attr_type %d len %d (rem %d)", nla, nla->nla_type, nla->nla_len, len);
136 		if (nla->nla_len < sizeof(struct nlattr)) {
137 			NLMSG_REPORT_ERR_MSG(npt, "Invalid attr %p type %d len: %d",
138 			    nla, nla->nla_type, nla->nla_len);
139 			uint32_t off = (char *)nla - (char *)npt->hdr;
140 			nlmsg_report_err_offset(npt, off);
141 			return (EINVAL);
142 		}
143 
144 		int nla_type = nla->nla_type & NLA_TYPE_MASK;
145 		const struct nlattr_parser *s = search_states(ps, pslen, nla_type);
146 		if (s != NULL) {
147 			void *ptr = (void *)((char *)target + s->off);
148 			error = s->cb(nla, npt, s->arg, ptr);
149 			if (error != 0) {
150 				uint32_t off = (char *)nla - (char *)npt->hdr;
151 				nlmsg_report_err_offset(npt, off);
152 				NL_LOG(LOG_DEBUG3, "parse failed att offset %u", off);
153 				return (error);
154 			}
155 		} else {
156 			/* Ignore non-specified attributes */
157 			NL_LOG(LOG_DEBUG3, "ignoring attr %d", nla->nla_type);
158 		}
159 	}
160 	if (len >= sizeof(struct nlattr)) {
161 		nla = (struct nlattr *)((char *)nla_head + (orig_len - len));
162 		NL_LOG(LOG_DEBUG3, " >>> end %p attr_type %d len %d", nla,
163 		    nla->nla_type, nla->nla_len);
164 	}
165 	NL_LOG(LOG_DEBUG3, "end parse: %p remaining_len %d", nla, len);
166 
167 	return (0);
168 }
169 
170 void
171 nl_get_attrs_bmask_raw(struct nlattr *nla_head, int len, struct nlattr_bmask *bm)
172 {
173 	struct nlattr *nla = NULL;
174 
175 	BIT_ZERO(NL_ATTR_BMASK_SIZE, bm);
176 
177 	NLA_FOREACH(nla, nla_head, len) {
178 		if (nla->nla_len < sizeof(struct nlattr))
179 			return;
180 		int nla_type = nla->nla_type & NLA_TYPE_MASK;
181 		if (nla_type < NL_ATTR_BMASK_SIZE)
182 			BIT_SET(NL_ATTR_BMASK_SIZE, nla_type, bm);
183 		else
184 			NL_LOG(LOG_DEBUG2, "Skipping type %d in the mask: too short",
185 			    nla_type);
186 	}
187 }
188 
189 bool
190 nl_has_attr(const struct nlattr_bmask *bm, unsigned int nla_type)
191 {
192 	MPASS(nla_type < NL_ATTR_BMASK_SIZE);
193 
194 	return (BIT_ISSET(NL_ATTR_BMASK_SIZE, nla_type, bm));
195 }
196 
197 int
198 nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
199 {
200 	if (__predict_false(NLA_DATA_LEN(nla) != 0)) {
201 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not a flag",
202 		    nla->nla_type, NLA_DATA_LEN(nla));
203 		return (EINVAL);
204 	}
205 
206 	*((uint8_t *)target) = 1;
207 	return (0);
208 }
209 
210 static struct sockaddr *
211 parse_rta_ip4(void *rta_data, struct nl_pstate *npt, int *perror)
212 {
213 	struct sockaddr_in *sin;
214 
215 	sin = (struct sockaddr_in *)npt_alloc_sockaddr(npt, sizeof(struct sockaddr_in));
216 	if (__predict_false(sin == NULL)) {
217 		*perror = ENOBUFS;
218 		return (NULL);
219 	}
220 	sin->sin_len = sizeof(struct sockaddr_in);
221 	sin->sin_family = AF_INET;
222 	memcpy(&sin->sin_addr, rta_data, sizeof(struct in_addr));
223 	return ((struct sockaddr *)sin);
224 }
225 
226 static struct sockaddr *
227 parse_rta_ip6(void *rta_data, struct nl_pstate *npt, int *perror)
228 {
229 	struct sockaddr_in6 *sin6;
230 
231 	sin6 = (struct sockaddr_in6 *)npt_alloc_sockaddr(npt, sizeof(struct sockaddr_in6));
232 	if (__predict_false(sin6 == NULL)) {
233 		*perror = ENOBUFS;
234 		return (NULL);
235 	}
236 	sin6->sin6_len = sizeof(struct sockaddr_in6);
237 	sin6->sin6_family = AF_INET6;
238 	memcpy(&sin6->sin6_addr, rta_data, sizeof(struct in6_addr));
239 	return ((struct sockaddr *)sin6);
240 }
241 
242 static struct sockaddr *
243 parse_rta_ip(struct rtattr *rta, struct nl_pstate *npt, int *perror)
244 {
245 	void *rta_data = NL_RTA_DATA(rta);
246 	int rta_len = NL_RTA_DATA_LEN(rta);
247 
248 	if (rta_len == sizeof(struct in_addr)) {
249 		return (parse_rta_ip4(rta_data, npt, perror));
250 	} else if (rta_len == sizeof(struct in6_addr)) {
251 		return (parse_rta_ip6(rta_data, npt, perror));
252 	} else {
253 		NLMSG_REPORT_ERR_MSG(npt, "unknown IP len: %d for rta type %d",
254 		    rta_len, rta->rta_type);
255 		*perror = ENOTSUP;
256 		return (NULL);
257 	}
258 	return (NULL);
259 }
260 
261 int
262 nlattr_get_ip(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
263 {
264 	int error = 0;
265 
266 	struct sockaddr *sa = parse_rta_ip((struct rtattr *)nla, npt, &error);
267 
268 	*((struct sockaddr **)target) = sa;
269 	return (error);
270 }
271 
272 static struct sockaddr *
273 parse_rta_via(struct rtattr *rta, struct nl_pstate *npt, int *perror)
274 {
275 	struct rtvia *via = NL_RTA_DATA(rta);
276 	int data_len = NL_RTA_DATA_LEN(rta);
277 
278 	if (__predict_false(data_len) < sizeof(struct rtvia)) {
279 		NLMSG_REPORT_ERR_MSG(npt, "undersized RTA_VIA(%d) attr: len %d",
280 		    rta->rta_type, data_len);
281 		*perror = EINVAL;
282 		return (NULL);
283 	}
284 	data_len -= offsetof(struct rtvia, rtvia_addr);
285 
286 	switch (via->rtvia_family) {
287 	case AF_INET:
288 		if (__predict_false(data_len < sizeof(struct in_addr))) {
289 			*perror = EINVAL;
290 			return (NULL);
291 		}
292 		return (parse_rta_ip4(via->rtvia_addr, npt, perror));
293 	case AF_INET6:
294 		if (__predict_false(data_len < sizeof(struct in6_addr))) {
295 			*perror = EINVAL;
296 			return (NULL);
297 		}
298 		return (parse_rta_ip6(via->rtvia_addr, npt, perror));
299 	default:
300 		*perror = ENOTSUP;
301 		return (NULL);
302 	}
303 }
304 
305 int
306 nlattr_get_ipvia(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
307 {
308 	int error = 0;
309 
310 	struct sockaddr *sa = parse_rta_via((struct rtattr *)nla, npt, &error);
311 
312 	*((struct sockaddr **)target) = sa;
313 	return (error);
314 }
315 
316 
317 int
318 nlattr_get_uint16(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
319 {
320 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint16_t))) {
321 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
322 		    nla->nla_type, NLA_DATA_LEN(nla));
323 		return (EINVAL);
324 	}
325 	*((uint16_t *)target) = *((const uint16_t *)NL_RTA_DATA_CONST(nla));
326 	return (0);
327 }
328 
329 int
330 nlattr_get_uint32(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
331 {
332 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint32_t))) {
333 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
334 		    nla->nla_type, NLA_DATA_LEN(nla));
335 		return (EINVAL);
336 	}
337 	*((uint32_t *)target) = *((const uint32_t *)NL_RTA_DATA_CONST(nla));
338 	return (0);
339 }
340 
341 int
342 nlattr_get_uint64(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
343 {
344 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint64_t))) {
345 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint64",
346 		    nla->nla_type, NLA_DATA_LEN(nla));
347 		return (EINVAL);
348 	}
349 	memcpy(target, NL_RTA_DATA_CONST(nla), sizeof(uint64_t));
350 	return (0);
351 }
352 
353 int
354 nlattr_get_in_addr(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
355 {
356 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(in_addr_t))) {
357 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not in_addr_t",
358 		    nla->nla_type, NLA_DATA_LEN(nla));
359 		return (EINVAL);
360 	}
361 	memcpy(target, NLA_DATA_CONST(nla), sizeof(in_addr_t));
362 	return (0);
363 }
364 
365 int
366 nlattr_get_in6_addr(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
367 {
368 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(struct in6_addr))) {
369 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not struct in6_addr",
370 		    nla->nla_type, NLA_DATA_LEN(nla));
371 		return (EINVAL);
372 	}
373 	memcpy(target, NLA_DATA_CONST(nla), sizeof(struct in6_addr));
374 	return (0);
375 }
376 
377 static int
378 nlattr_get_ifp_internal(struct nlattr *nla, struct nl_pstate *npt,
379     void *target, bool zero_ok)
380 {
381 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint32_t))) {
382 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
383 		    nla->nla_type, NLA_DATA_LEN(nla));
384 		return (EINVAL);
385 	}
386 	uint32_t ifindex = *((const uint32_t *)NLA_DATA_CONST(nla));
387 
388 	if (ifindex == 0 && zero_ok) {
389 		*((struct ifnet **)target) = NULL;
390 		return (0);
391 	}
392 
393 	NET_EPOCH_ASSERT();
394 
395 	struct ifnet *ifp = ifnet_byindex(ifindex);
396 	if (__predict_false(ifp == NULL)) {
397 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d: ifindex %u invalid",
398 		    nla->nla_type, ifindex);
399 		return (ENOENT);
400 	}
401 	*((struct ifnet **)target) = ifp;
402 	NL_LOG(LOG_DEBUG3, "nla type %d: ifindex %u -> %s", nla->nla_type,
403 	    ifindex, if_name(ifp));
404 
405 	return (0);
406 }
407 
408 int
409 nlattr_get_ifp(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
410 {
411 	return (nlattr_get_ifp_internal(nla, npt, target, false));
412 }
413 
414 int
415 nlattr_get_ifpz(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
416 {
417 	return (nlattr_get_ifp_internal(nla, npt, target, true));
418 }
419 
420 int
421 nlattr_get_string(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
422 {
423 	int maxlen = NLA_DATA_LEN(nla);
424 
425 	if (__predict_false(strnlen((char *)NLA_DATA(nla), maxlen) >= maxlen)) {
426 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not NULL-terminated",
427 		    nla->nla_type, maxlen);
428 		return (EINVAL);
429 	}
430 
431 	*((char **)target) = (char *)NLA_DATA(nla);
432 	return (0);
433 }
434 
435 int
436 nlattr_get_stringn(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
437 {
438 	int maxlen = NLA_DATA_LEN(nla);
439 
440 	char *buf = npt_alloc(npt, maxlen + 1);
441 	if (buf == NULL)
442 		return (ENOMEM);
443 	buf[maxlen] = '\0';
444 	memcpy(buf, NLA_DATA(nla), maxlen);
445 
446 	*((char **)target) = buf;
447 	return (0);
448 }
449 int
450 nlattr_get_nla(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
451 {
452 	NL_LOG(LOG_DEBUG3, "STORING %p len %d", nla, nla->nla_len);
453 	*((struct nlattr **)target) = nla;
454 	return (0);
455 }
456 
457 int
458 nlattr_get_nested(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
459 {
460 	const struct nlhdr_parser *p = (const struct nlhdr_parser *)arg;
461 	int error;
462 
463 	/* Assumes target points to the beginning of the structure */
464 	error = nl_parse_header(NLA_DATA(nla), NLA_DATA_LEN(nla), p, npt, target);
465 	return (error);
466 }
467 
468 int
469 nlf_get_ifp(void *src, struct nl_pstate *npt, void *target)
470 {
471 	int ifindex = *((const int *)src);
472 
473 	NET_EPOCH_ASSERT();
474 
475 	struct ifnet *ifp = ifnet_byindex(ifindex);
476 	if (ifp == NULL) {
477 		NL_LOG(LOG_DEBUG, "ifindex %u invalid", ifindex);
478 		return (ENOENT);
479 	}
480 	*((struct ifnet **)target) = ifp;
481 
482 	return (0);
483 }
484 
485 int
486 nlf_get_ifpz(void *src, struct nl_pstate *npt, void *target)
487 {
488 	int ifindex = *((const int *)src);
489 
490 	NET_EPOCH_ASSERT();
491 
492 	struct ifnet *ifp = ifnet_byindex(ifindex);
493 	if (ifindex != 0 && ifp == NULL) {
494 		NL_LOG(LOG_DEBUG, "ifindex %u invalid", ifindex);
495 		return (ENOENT);
496 	}
497 	*((struct ifnet **)target) = ifp;
498 
499 	return (0);
500 }
501 
502 int
503 nlf_get_u8(void *src, struct nl_pstate *npt, void *target)
504 {
505 	uint8_t val = *((const uint8_t *)src);
506 
507 	*((uint8_t *)target) = val;
508 
509 	return (0);
510 }
511 
512 int
513 nlf_get_u8_u32(void *src, struct nl_pstate *npt, void *target)
514 {
515 	*((uint32_t *)target) = *((const uint8_t *)src);
516 	return (0);
517 }
518 
519 int
520 nlf_get_u16(void *src, struct nl_pstate *npt, void *target)
521 {
522 	*((uint16_t *)target) = *((const uint16_t *)src);
523 	return (0);
524 }
525 
526 int
527 nlf_get_u32(void *src, struct nl_pstate *npt, void *target)
528 {
529 	*((uint32_t *)target) = *((const uint32_t *)src);
530 	return (0);
531 }
532 
533