xref: /freebsd/sys/netlink/netlink_message_parser.c (revision af23369a6deaaeb612ab266eb88b8bb8d560c322) 
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 <netlink/netlink.h>
45 #include <netlink/netlink_ctl.h>
46 #include <netlink/netlink_var.h>
47 #include <netlink/netlink_route.h>
48 
49 #define	DEBUG_MOD_NAME	nl_parser
50 #define	DEBUG_MAX_LEVEL	LOG_DEBUG3
51 #include <netlink/netlink_debug.h>
52 _DECLARE_DEBUG(LOG_DEBUG);
53 
54 bool
55 nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...)
56 {
57 	va_list ap;
58 
59 	if (npt->err_msg != NULL)
60 		return (false);
61 	char *buf = npt_alloc(npt, NL_MAX_ERROR_BUF);
62 	if (buf == NULL)
63 		return (false);
64 	va_start(ap, fmt);
65 	vsnprintf(buf, NL_MAX_ERROR_BUF, fmt, ap);
66 	va_end(ap);
67 
68 	npt->err_msg = buf;
69 	return (true);
70 }
71 
72 bool
73 nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off)
74 {
75 	if (npt->err_off != 0)
76 		return (false);
77 	npt->err_off = off;
78 	return (true);
79 }
80 
81 void
82 nlmsg_report_cookie(struct nl_pstate *npt, struct nlattr *nla)
83 {
84 	MPASS(nla->nla_type == NLMSGERR_ATTR_COOKIE);
85 	MPASS(nla->nla_len >= sizeof(struct nlattr));
86 	npt->cookie = nla;
87 }
88 
89 void
90 nlmsg_report_cookie_u32(struct nl_pstate *npt, uint32_t val)
91 {
92 	struct nlattr *nla = npt_alloc(npt, sizeof(*nla) + sizeof(uint32_t));
93 
94 	nla->nla_type = NLMSGERR_ATTR_COOKIE;
95 	nla->nla_len = sizeof(*nla) + sizeof(uint32_t);
96 	memcpy(nla + 1, &val, sizeof(uint32_t));
97 	nlmsg_report_cookie(npt, nla);
98 }
99 
100 static const struct nlattr_parser *
101 search_states(const struct nlattr_parser *ps, int pslen, int key)
102 {
103 	int left_i = 0, right_i = pslen - 1;
104 
105 	if (key < ps[0].type || key > ps[pslen - 1].type)
106 		return (NULL);
107 
108 	while (left_i + 1 < right_i) {
109 		int mid_i = (left_i + right_i) / 2;
110 		if (key < ps[mid_i].type)
111 			right_i = mid_i;
112 		else if (key > ps[mid_i].type)
113 			left_i = mid_i + 1;
114 		else
115 			return (&ps[mid_i]);
116 	}
117 	if (ps[left_i].type == key)
118 		return (&ps[left_i]);
119 	else if (ps[right_i].type == key)
120 		return (&ps[right_i]);
121 	return (NULL);
122 }
123 
124 int
125 nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser *ps, int pslen,
126     struct nl_pstate *npt, void *target)
127 {
128 	struct nlattr *nla = NULL;
129 	int error = 0;
130 
131 	NL_LOG(LOG_DEBUG3, "parse %p remaining_len %d", nla_head, len);
132 	int orig_len = len;
133 	NLA_FOREACH(nla, nla_head, len) {
134 		NL_LOG(LOG_DEBUG3, ">> parsing %p attr_type %d len %d (rem %d)", nla, nla->nla_type, nla->nla_len, len);
135 		if (nla->nla_len < sizeof(struct nlattr)) {
136 			NLMSG_REPORT_ERR_MSG(npt, "Invalid attr %p type %d len: %d",
137 			    nla, nla->nla_type, nla->nla_len);
138 			uint32_t off = (char *)nla - (char *)npt->hdr;
139 			nlmsg_report_err_offset(npt, off);
140 			return (EINVAL);
141 		}
142 
143 		int nla_type = nla->nla_type & NLA_TYPE_MASK;
144 		const struct nlattr_parser *s = search_states(ps, pslen, nla_type);
145 		if (s != NULL) {
146 			void *ptr = (void *)((char *)target + s->off);
147 			error = s->cb(nla, npt, s->arg, ptr);
148 			if (error != 0) {
149 				uint32_t off = (char *)nla - (char *)npt->hdr;
150 				nlmsg_report_err_offset(npt, off);
151 				NL_LOG(LOG_DEBUG3, "parse failed att offset %u", off);
152 				return (error);
153 			}
154 		} else {
155 			/* Ignore non-specified attributes */
156 			NL_LOG(LOG_DEBUG3, "ignoring attr %d", nla->nla_type);
157 		}
158 	}
159 	if (len >= sizeof(struct nlattr)) {
160 		nla = (struct nlattr *)((char *)nla_head + (orig_len - len));
161 		NL_LOG(LOG_DEBUG3, " >>> end %p attr_type %d len %d", nla,
162 		    nla->nla_type, nla->nla_len);
163 	}
164 	NL_LOG(LOG_DEBUG3, "end parse: %p remaining_len %d", nla, len);
165 
166 	return (0);
167 }
168 
169 void
170 nl_get_attrs_bmask_raw(struct nlattr *nla_head, int len, struct nlattr_bmask *bm)
171 {
172 	struct nlattr *nla = NULL;
173 
174 	BIT_ZERO(NL_ATTR_BMASK_SIZE, bm);
175 
176 	NLA_FOREACH(nla, nla_head, len) {
177 		if (nla->nla_len < sizeof(struct nlattr))
178 			return;
179 		int nla_type = nla->nla_type & NLA_TYPE_MASK;
180 		if (nla_type < NL_ATTR_BMASK_SIZE)
181 			BIT_SET(NL_ATTR_BMASK_SIZE, nla_type, bm);
182 		else
183 			NL_LOG(LOG_DEBUG2, "Skipping type %d in the mask: too short",
184 			    nla_type);
185 	}
186 }
187 
188 bool
189 nl_has_attr(const struct nlattr_bmask *bm, unsigned int nla_type)
190 {
191 	MPASS(nla_type < NL_ATTR_BMASK_SIZE);
192 
193 	return (BIT_ISSET(NL_ATTR_BMASK_SIZE, nla_type, bm));
194 }
195 
196 int
197 nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
198 {
199 	if (__predict_false(NLA_DATA_LEN(nla) != 0)) {
200 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not a flag",
201 		    nla->nla_type, NLA_DATA_LEN(nla));
202 		return (EINVAL);
203 	}
204 
205 	*((uint8_t *)target) = 1;
206 	return (0);
207 }
208 
209 static struct sockaddr *
210 parse_rta_ip4(void *rta_data, struct nl_pstate *npt, int *perror)
211 {
212 	struct sockaddr_in *sin;
213 
214 	sin = (struct sockaddr_in *)npt_alloc_sockaddr(npt, sizeof(struct sockaddr_in));
215 	if (__predict_false(sin == NULL)) {
216 		*perror = ENOBUFS;
217 		return (NULL);
218 	}
219 	sin->sin_len = sizeof(struct sockaddr_in);
220 	sin->sin_family = AF_INET;
221 	memcpy(&sin->sin_addr, rta_data, sizeof(struct in_addr));
222 	return ((struct sockaddr *)sin);
223 }
224 
225 static struct sockaddr *
226 parse_rta_ip6(void *rta_data, struct nl_pstate *npt, int *perror)
227 {
228 	struct sockaddr_in6 *sin6;
229 
230 	sin6 = (struct sockaddr_in6 *)npt_alloc_sockaddr(npt, sizeof(struct sockaddr_in6));
231 	if (__predict_false(sin6 == NULL)) {
232 		*perror = ENOBUFS;
233 		return (NULL);
234 	}
235 	sin6->sin6_len = sizeof(struct sockaddr_in6);
236 	sin6->sin6_family = AF_INET6;
237 	memcpy(&sin6->sin6_addr, rta_data, sizeof(struct in6_addr));
238 	return ((struct sockaddr *)sin6);
239 }
240 
241 static struct sockaddr *
242 parse_rta_ip(struct rtattr *rta, struct nl_pstate *npt, int *perror)
243 {
244 	void *rta_data = NL_RTA_DATA(rta);
245 	int rta_len = NL_RTA_DATA_LEN(rta);
246 
247 	if (rta_len == sizeof(struct in_addr)) {
248 		return (parse_rta_ip4(rta_data, npt, perror));
249 	} else if (rta_len == sizeof(struct in6_addr)) {
250 		return (parse_rta_ip6(rta_data, npt, perror));
251 	} else {
252 		NLMSG_REPORT_ERR_MSG(npt, "unknown IP len: %d for rta type %d",
253 		    rta_len, rta->rta_type);
254 		*perror = ENOTSUP;
255 		return (NULL);
256 	}
257 	return (NULL);
258 }
259 
260 int
261 nlattr_get_ip(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
262 {
263 	int error = 0;
264 
265 	struct sockaddr *sa = parse_rta_ip((struct rtattr *)nla, npt, &error);
266 
267 	*((struct sockaddr **)target) = sa;
268 	return (error);
269 }
270 
271 static struct sockaddr *
272 parse_rta_via(struct rtattr *rta, struct nl_pstate *npt, int *perror)
273 {
274 	struct rtvia *via = NL_RTA_DATA(rta);
275 	int data_len = NL_RTA_DATA_LEN(rta);
276 
277 	if (__predict_false(data_len) < sizeof(struct rtvia)) {
278 		NLMSG_REPORT_ERR_MSG(npt, "undersized RTA_VIA(%d) attr: len %d",
279 		    rta->rta_type, data_len);
280 		*perror = EINVAL;
281 		return (NULL);
282 	}
283 	data_len -= offsetof(struct rtvia, rtvia_addr);
284 
285 	switch (via->rtvia_family) {
286 	case AF_INET:
287 		if (__predict_false(data_len < sizeof(struct in_addr))) {
288 			*perror = EINVAL;
289 			return (NULL);
290 		}
291 		return (parse_rta_ip4(via->rtvia_addr, npt, perror));
292 	case AF_INET6:
293 		if (__predict_false(data_len < sizeof(struct in6_addr))) {
294 			*perror = EINVAL;
295 			return (NULL);
296 		}
297 		return (parse_rta_ip6(via->rtvia_addr, npt, perror));
298 	default:
299 		*perror = ENOTSUP;
300 		return (NULL);
301 	}
302 }
303 
304 int
305 nlattr_get_ipvia(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
306 {
307 	int error = 0;
308 
309 	struct sockaddr *sa = parse_rta_via((struct rtattr *)nla, npt, &error);
310 
311 	*((struct sockaddr **)target) = sa;
312 	return (error);
313 }
314 
315 
316 int
317 nlattr_get_uint16(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
318 {
319 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint16_t))) {
320 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
321 		    nla->nla_type, NLA_DATA_LEN(nla));
322 		return (EINVAL);
323 	}
324 	*((uint16_t *)target) = *((const uint16_t *)NL_RTA_DATA_CONST(nla));
325 	return (0);
326 }
327 
328 int
329 nlattr_get_uint32(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
330 {
331 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint32_t))) {
332 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
333 		    nla->nla_type, NLA_DATA_LEN(nla));
334 		return (EINVAL);
335 	}
336 	*((uint32_t *)target) = *((const uint32_t *)NL_RTA_DATA_CONST(nla));
337 	return (0);
338 }
339 
340 int
341 nlattr_get_uint64(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
342 {
343 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint64_t))) {
344 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint64",
345 		    nla->nla_type, NLA_DATA_LEN(nla));
346 		return (EINVAL);
347 	}
348 	memcpy(target, NL_RTA_DATA_CONST(nla), sizeof(uint64_t));
349 	return (0);
350 }
351 
352 static int
353 nlattr_get_ifp_internal(struct nlattr *nla, struct nl_pstate *npt,
354     void *target, bool zero_ok)
355 {
356 	if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint32_t))) {
357 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
358 		    nla->nla_type, NLA_DATA_LEN(nla));
359 		return (EINVAL);
360 	}
361 	uint32_t ifindex = *((const uint32_t *)NLA_DATA_CONST(nla));
362 
363 	if (ifindex == 0 && zero_ok) {
364 		*((struct ifnet **)target) = NULL;
365 		return (0);
366 	}
367 
368 	NET_EPOCH_ASSERT();
369 
370 	struct ifnet *ifp = ifnet_byindex(ifindex);
371 	if (__predict_false(ifp == NULL)) {
372 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d: ifindex %u invalid",
373 		    nla->nla_type, ifindex);
374 		return (ENOENT);
375 	}
376 	*((struct ifnet **)target) = ifp;
377 	NL_LOG(LOG_DEBUG3, "nla type %d: ifindex %u -> %s", nla->nla_type,
378 	    ifindex, if_name(ifp));
379 
380 	return (0);
381 }
382 
383 int
384 nlattr_get_ifp(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
385 {
386 	return (nlattr_get_ifp_internal(nla, npt, target, false));
387 }
388 
389 int
390 nlattr_get_ifpz(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
391 {
392 	return (nlattr_get_ifp_internal(nla, npt, target, true));
393 }
394 
395 int
396 nlattr_get_string(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
397 {
398 	int maxlen = NLA_DATA_LEN(nla);
399 
400 	if (__predict_false(strnlen((char *)NLA_DATA(nla), maxlen) >= maxlen)) {
401 		NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not NULL-terminated",
402 		    nla->nla_type, maxlen);
403 		return (EINVAL);
404 	}
405 
406 	*((char **)target) = (char *)NLA_DATA(nla);
407 	return (0);
408 }
409 
410 int
411 nlattr_get_stringn(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
412 {
413 	int maxlen = NLA_DATA_LEN(nla);
414 
415 	char *buf = npt_alloc(npt, maxlen + 1);
416 	if (buf == NULL)
417 		return (ENOMEM);
418 	buf[maxlen] = '\0';
419 	memcpy(buf, NLA_DATA(nla), maxlen);
420 
421 	*((char **)target) = buf;
422 	return (0);
423 }
424 int
425 nlattr_get_nla(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
426 {
427 	NL_LOG(LOG_DEBUG3, "STORING %p len %d", nla, nla->nla_len);
428 	*((struct nlattr **)target) = nla;
429 	return (0);
430 }
431 
432 int
433 nlattr_get_nested(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
434 {
435 	const struct nlhdr_parser *p = (const struct nlhdr_parser *)arg;
436 	int error;
437 
438 	/* Assumes target points to the beginning of the structure */
439 	error = nl_parse_header(NLA_DATA(nla), NLA_DATA_LEN(nla), p, npt, target);
440 	return (error);
441 }
442 
443 int
444 nlf_get_ifp(void *src, struct nl_pstate *npt, void *target)
445 {
446 	int ifindex = *((const int *)src);
447 
448 	NET_EPOCH_ASSERT();
449 
450 	struct ifnet *ifp = ifnet_byindex(ifindex);
451 	if (ifp == NULL) {
452 		NL_LOG(LOG_DEBUG, "ifindex %u invalid", ifindex);
453 		return (ENOENT);
454 	}
455 	*((struct ifnet **)target) = ifp;
456 
457 	return (0);
458 }
459 
460 int
461 nlf_get_ifpz(void *src, struct nl_pstate *npt, void *target)
462 {
463 	int ifindex = *((const int *)src);
464 
465 	NET_EPOCH_ASSERT();
466 
467 	struct ifnet *ifp = ifnet_byindex(ifindex);
468 	if (ifindex != 0 && ifp == NULL) {
469 		NL_LOG(LOG_DEBUG, "ifindex %u invalid", ifindex);
470 		return (ENOENT);
471 	}
472 	*((struct ifnet **)target) = ifp;
473 
474 	return (0);
475 }
476 
477 int
478 nlf_get_u8(void *src, struct nl_pstate *npt, void *target)
479 {
480 	uint8_t val = *((const uint8_t *)src);
481 
482 	*((uint8_t *)target) = val;
483 
484 	return (0);
485 }
486 
487 int
488 nlf_get_u8_u32(void *src, struct nl_pstate *npt, void *target)
489 {
490 	*((uint32_t *)target) = *((const uint8_t *)src);
491 	return (0);
492 }
493 
494 int
495 nlf_get_u16(void *src, struct nl_pstate *npt, void *target)
496 {
497 	*((uint16_t *)target) = *((const uint16_t *)src);
498 	return (0);
499 }
500 
501 int
502 nlf_get_u32(void *src, struct nl_pstate *npt, void *target)
503 {
504 	*((uint32_t *)target) = *((const uint32_t *)src);
505 	return (0);
506 }
507 
508