FreeBSD/Linux Kernel Cross Reference
sys/netinet/in_jail.c
1 /*-
2 * Copyright (c) 1999 Poul-Henning Kamp.
3 * Copyright (c) 2008 Bjoern A. Zeeb.
4 * Copyright (c) 2009 James Gritton.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: releng/11.1/sys/netinet/in_jail.c 316944 2017-04-14 22:02:08Z smh $");
31
32 #include "opt_compat.h"
33 #include "opt_ddb.h"
34 #include "opt_inet.h"
35 #include "opt_inet6.h"
36
37 #include <sys/param.h>
38 #include <sys/types.h>
39 #include <sys/kernel.h>
40 #include <sys/systm.h>
41 #include <sys/errno.h>
42 #include <sys/sysproto.h>
43 #include <sys/malloc.h>
44 #include <sys/osd.h>
45 #include <sys/priv.h>
46 #include <sys/proc.h>
47 #include <sys/taskqueue.h>
48 #include <sys/fcntl.h>
49 #include <sys/jail.h>
50 #include <sys/lock.h>
51 #include <sys/mutex.h>
52 #include <sys/racct.h>
53 #include <sys/refcount.h>
54 #include <sys/sx.h>
55 #include <sys/sysent.h>
56 #include <sys/namei.h>
57 #include <sys/mount.h>
58 #include <sys/queue.h>
59 #include <sys/socket.h>
60 #include <sys/syscallsubr.h>
61 #include <sys/sysctl.h>
62 #include <sys/vnode.h>
63
64 #include <net/if.h>
65 #include <net/vnet.h>
66
67 #include <netinet/in.h>
68
69 int
70 prison_qcmp_v4(const void *ip1, const void *ip2)
71 {
72 in_addr_t iaa, iab;
73
74 /*
75 * We need to compare in HBO here to get the list sorted as expected
76 * by the result of the code. Sorting NBO addresses gives you
77 * interesting results. If you do not understand, do not try.
78 */
79 iaa = ntohl(((const struct in_addr *)ip1)->s_addr);
80 iab = ntohl(((const struct in_addr *)ip2)->s_addr);
81
82 /*
83 * Do not simply return the difference of the two numbers, the int is
84 * not wide enough.
85 */
86 if (iaa > iab)
87 return (1);
88 else if (iaa < iab)
89 return (-1);
90 else
91 return (0);
92 }
93
94 /*
95 * Restrict a prison's IP address list with its parent's, possibly replacing
96 * it. Return true if the replacement buffer was used (or would have been).
97 */
98 int
99 prison_restrict_ip4(struct prison *pr, struct in_addr *newip4)
100 {
101 int ii, ij, used;
102 struct prison *ppr;
103
104 ppr = pr->pr_parent;
105 if (!(pr->pr_flags & PR_IP4_USER)) {
106 /* This has no user settings, so just copy the parent's list. */
107 if (pr->pr_ip4s < ppr->pr_ip4s) {
108 /*
109 * There's no room for the parent's list. Use the
110 * new list buffer, which is assumed to be big enough
111 * (if it was passed). If there's no buffer, try to
112 * allocate one.
113 */
114 used = 1;
115 if (newip4 == NULL) {
116 newip4 = malloc(ppr->pr_ip4s * sizeof(*newip4),
117 M_PRISON, M_NOWAIT);
118 if (newip4 != NULL)
119 used = 0;
120 }
121 if (newip4 != NULL) {
122 bcopy(ppr->pr_ip4, newip4,
123 ppr->pr_ip4s * sizeof(*newip4));
124 free(pr->pr_ip4, M_PRISON);
125 pr->pr_ip4 = newip4;
126 pr->pr_ip4s = ppr->pr_ip4s;
127 }
128 return (used);
129 }
130 pr->pr_ip4s = ppr->pr_ip4s;
131 if (pr->pr_ip4s > 0)
132 bcopy(ppr->pr_ip4, pr->pr_ip4,
133 pr->pr_ip4s * sizeof(*newip4));
134 else if (pr->pr_ip4 != NULL) {
135 free(pr->pr_ip4, M_PRISON);
136 pr->pr_ip4 = NULL;
137 }
138 } else if (pr->pr_ip4s > 0) {
139 /* Remove addresses that aren't in the parent. */
140 for (ij = 0; ij < ppr->pr_ip4s; ij++)
141 if (pr->pr_ip4[0].s_addr == ppr->pr_ip4[ij].s_addr)
142 break;
143 if (ij < ppr->pr_ip4s)
144 ii = 1;
145 else {
146 bcopy(pr->pr_ip4 + 1, pr->pr_ip4,
147 --pr->pr_ip4s * sizeof(*pr->pr_ip4));
148 ii = 0;
149 }
150 for (ij = 1; ii < pr->pr_ip4s; ) {
151 if (pr->pr_ip4[ii].s_addr == ppr->pr_ip4[0].s_addr) {
152 ii++;
153 continue;
154 }
155 switch (ij >= ppr->pr_ip4s ? -1 :
156 prison_qcmp_v4(&pr->pr_ip4[ii], &ppr->pr_ip4[ij])) {
157 case -1:
158 bcopy(pr->pr_ip4 + ii + 1, pr->pr_ip4 + ii,
159 (--pr->pr_ip4s - ii) * sizeof(*pr->pr_ip4));
160 break;
161 case 0:
162 ii++;
163 ij++;
164 break;
165 case 1:
166 ij++;
167 break;
168 }
169 }
170 if (pr->pr_ip4s == 0) {
171 free(pr->pr_ip4, M_PRISON);
172 pr->pr_ip4 = NULL;
173 }
174 }
175 return (0);
176 }
177
178 /*
179 * Pass back primary IPv4 address of this jail.
180 *
181 * If not restricted return success but do not alter the address. Caller has
182 * to make sure to initialize it correctly (e.g. INADDR_ANY).
183 *
184 * Returns 0 on success, EAFNOSUPPORT if the jail doesn't allow IPv4.
185 * Address returned in NBO.
186 */
187 int
188 prison_get_ip4(struct ucred *cred, struct in_addr *ia)
189 {
190 struct prison *pr;
191
192 KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
193 KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
194
195 pr = cred->cr_prison;
196 if (!(pr->pr_flags & PR_IP4))
197 return (0);
198 mtx_lock(&pr->pr_mtx);
199 if (!(pr->pr_flags & PR_IP4)) {
200 mtx_unlock(&pr->pr_mtx);
201 return (0);
202 }
203 if (pr->pr_ip4 == NULL) {
204 mtx_unlock(&pr->pr_mtx);
205 return (EAFNOSUPPORT);
206 }
207
208 ia->s_addr = pr->pr_ip4[0].s_addr;
209 mtx_unlock(&pr->pr_mtx);
210 return (0);
211 }
212
213 /*
214 * Return 1 if we should do proper source address selection or are not jailed.
215 * We will return 0 if we should bypass source address selection in favour
216 * of the primary jail IPv4 address. Only in this case *ia will be updated and
217 * returned in NBO.
218 * Return EAFNOSUPPORT, in case this jail does not allow IPv4.
219 */
220 int
221 prison_saddrsel_ip4(struct ucred *cred, struct in_addr *ia)
222 {
223 struct prison *pr;
224 struct in_addr lia;
225 int error;
226
227 KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
228 KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
229
230 if (!jailed(cred))
231 return (1);
232
233 pr = cred->cr_prison;
234 if (pr->pr_flags & PR_IP4_SADDRSEL)
235 return (1);
236
237 lia.s_addr = INADDR_ANY;
238 error = prison_get_ip4(cred, &lia);
239 if (error)
240 return (error);
241 if (lia.s_addr == INADDR_ANY)
242 return (1);
243
244 ia->s_addr = lia.s_addr;
245 return (0);
246 }
247
248 /*
249 * Return true if pr1 and pr2 have the same IPv4 address restrictions.
250 */
251 int
252 prison_equal_ip4(struct prison *pr1, struct prison *pr2)
253 {
254
255 if (pr1 == pr2)
256 return (1);
257
258 /*
259 * No need to lock since the PR_IP4_USER flag can't be altered for
260 * existing prisons.
261 */
262 while (pr1 != &prison0 &&
263 #ifdef VIMAGE
264 !(pr1->pr_flags & PR_VNET) &&
265 #endif
266 !(pr1->pr_flags & PR_IP4_USER))
267 pr1 = pr1->pr_parent;
268 while (pr2 != &prison0 &&
269 #ifdef VIMAGE
270 !(pr2->pr_flags & PR_VNET) &&
271 #endif
272 !(pr2->pr_flags & PR_IP4_USER))
273 pr2 = pr2->pr_parent;
274 return (pr1 == pr2);
275 }
276
277 /*
278 * Make sure our (source) address is set to something meaningful to this
279 * jail.
280 *
281 * Returns 0 if jail doesn't restrict IPv4 or if address belongs to jail,
282 * EADDRNOTAVAIL if the address doesn't belong, or EAFNOSUPPORT if the jail
283 * doesn't allow IPv4. Address passed in in NBO and returned in NBO.
284 */
285 int
286 prison_local_ip4(struct ucred *cred, struct in_addr *ia)
287 {
288 struct prison *pr;
289 struct in_addr ia0;
290 int error;
291
292 KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
293 KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
294
295 pr = cred->cr_prison;
296 if (!(pr->pr_flags & PR_IP4))
297 return (0);
298 mtx_lock(&pr->pr_mtx);
299 if (!(pr->pr_flags & PR_IP4)) {
300 mtx_unlock(&pr->pr_mtx);
301 return (0);
302 }
303 if (pr->pr_ip4 == NULL) {
304 mtx_unlock(&pr->pr_mtx);
305 return (EAFNOSUPPORT);
306 }
307
308 ia0.s_addr = ntohl(ia->s_addr);
309
310 if (ia0.s_addr == INADDR_ANY) {
311 /*
312 * In case there is only 1 IPv4 address, bind directly.
313 */
314 if (pr->pr_ip4s == 1)
315 ia->s_addr = pr->pr_ip4[0].s_addr;
316 mtx_unlock(&pr->pr_mtx);
317 return (0);
318 }
319
320 error = prison_check_ip4_locked(pr, ia);
321 if (error == EADDRNOTAVAIL && ia0.s_addr == INADDR_LOOPBACK) {
322 ia->s_addr = pr->pr_ip4[0].s_addr;
323 error = 0;
324 }
325
326 mtx_unlock(&pr->pr_mtx);
327 return (error);
328 }
329
330 /*
331 * Rewrite destination address in case we will connect to loopback address.
332 *
333 * Returns 0 on success, EAFNOSUPPORT if the jail doesn't allow IPv4.
334 * Address passed in in NBO and returned in NBO.
335 */
336 int
337 prison_remote_ip4(struct ucred *cred, struct in_addr *ia)
338 {
339 struct prison *pr;
340
341 KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
342 KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
343
344 pr = cred->cr_prison;
345 if (!(pr->pr_flags & PR_IP4))
346 return (0);
347 mtx_lock(&pr->pr_mtx);
348 if (!(pr->pr_flags & PR_IP4)) {
349 mtx_unlock(&pr->pr_mtx);
350 return (0);
351 }
352 if (pr->pr_ip4 == NULL) {
353 mtx_unlock(&pr->pr_mtx);
354 return (EAFNOSUPPORT);
355 }
356
357 if (ntohl(ia->s_addr) == INADDR_LOOPBACK &&
358 prison_check_ip4_locked(pr, ia) == EADDRNOTAVAIL) {
359 ia->s_addr = pr->pr_ip4[0].s_addr;
360 mtx_unlock(&pr->pr_mtx);
361 return (0);
362 }
363
364 /*
365 * Return success because nothing had to be changed.
366 */
367 mtx_unlock(&pr->pr_mtx);
368 return (0);
369 }
370
371 /*
372 * Check if given address belongs to the jail referenced by cred/prison.
373 *
374 * Returns 0 if address belongs to jail,
375 * EADDRNOTAVAIL if the address doesn't belong to the jail.
376 */
377 int
378 prison_check_ip4_locked(const struct prison *pr, const struct in_addr *ia)
379 {
380 int i, a, z, d;
381
382 /*
383 * Check the primary IP.
384 */
385 if (pr->pr_ip4[0].s_addr == ia->s_addr)
386 return (0);
387
388 /*
389 * All the other IPs are sorted so we can do a binary search.
390 */
391 a = 0;
392 z = pr->pr_ip4s - 2;
393 while (a <= z) {
394 i = (a + z) / 2;
395 d = prison_qcmp_v4(&pr->pr_ip4[i+1], ia);
396 if (d > 0)
397 z = i - 1;
398 else if (d < 0)
399 a = i + 1;
400 else
401 return (0);
402 }
403
404 return (EADDRNOTAVAIL);
405 }
406
407 int
408 prison_check_ip4(const struct ucred *cred, const struct in_addr *ia)
409 {
410 struct prison *pr;
411 int error;
412
413 KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
414 KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
415
416 pr = cred->cr_prison;
417 if (!(pr->pr_flags & PR_IP4))
418 return (0);
419 mtx_lock(&pr->pr_mtx);
420 if (!(pr->pr_flags & PR_IP4)) {
421 mtx_unlock(&pr->pr_mtx);
422 return (0);
423 }
424 if (pr->pr_ip4 == NULL) {
425 mtx_unlock(&pr->pr_mtx);
426 return (EAFNOSUPPORT);
427 }
428
429 error = prison_check_ip4_locked(pr, ia);
430 mtx_unlock(&pr->pr_mtx);
431 return (error);
432 }
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