FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_jail.c
1 /*
2 * ----------------------------------------------------------------------------
3 * "THE BEER-WARE LICENSE" (Revision 42):
4 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
5 * can do whatever you want with this stuff. If we meet some day, and you think
6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
7 * ----------------------------------------------------------------------------
8 */
9
10 #include <sys/cdefs.h>
11 __FBSDID("$FreeBSD: releng/5.3/sys/kern/kern_jail.c 136588 2004-10-16 08:43:07Z cvs2svn $");
12
13 #include "opt_mac.h"
14
15 #include <sys/param.h>
16 #include <sys/types.h>
17 #include <sys/kernel.h>
18 #include <sys/systm.h>
19 #include <sys/errno.h>
20 #include <sys/sysproto.h>
21 #include <sys/mac.h>
22 #include <sys/malloc.h>
23 #include <sys/proc.h>
24 #include <sys/taskqueue.h>
25 #include <sys/jail.h>
26 #include <sys/lock.h>
27 #include <sys/mutex.h>
28 #include <sys/namei.h>
29 #include <sys/queue.h>
30 #include <sys/socket.h>
31 #include <sys/syscallsubr.h>
32 #include <sys/sysctl.h>
33 #include <sys/vnode.h>
34 #include <net/if.h>
35 #include <netinet/in.h>
36
37 MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
38
39 SYSCTL_DECL(_security);
40 SYSCTL_NODE(_security, OID_AUTO, jail, CTLFLAG_RW, 0,
41 "Jail rules");
42
43 mp_fixme("these variables need a lock")
44
45 int jail_set_hostname_allowed = 1;
46 SYSCTL_INT(_security_jail, OID_AUTO, set_hostname_allowed, CTLFLAG_RW,
47 &jail_set_hostname_allowed, 0,
48 "Processes in jail can set their hostnames");
49
50 int jail_socket_unixiproute_only = 1;
51 SYSCTL_INT(_security_jail, OID_AUTO, socket_unixiproute_only, CTLFLAG_RW,
52 &jail_socket_unixiproute_only, 0,
53 "Processes in jail are limited to creating UNIX/IPv4/route sockets only");
54
55 int jail_sysvipc_allowed = 0;
56 SYSCTL_INT(_security_jail, OID_AUTO, sysvipc_allowed, CTLFLAG_RW,
57 &jail_sysvipc_allowed, 0,
58 "Processes in jail can use System V IPC primitives");
59
60 int jail_getfsstatroot_only = 1;
61 SYSCTL_INT(_security_jail, OID_AUTO, getfsstatroot_only, CTLFLAG_RW,
62 &jail_getfsstatroot_only, 0,
63 "Processes see only their root file system in getfsstat()");
64
65 int jail_allow_raw_sockets = 0;
66 SYSCTL_INT(_security_jail, OID_AUTO, allow_raw_sockets, CTLFLAG_RW,
67 &jail_allow_raw_sockets, 0,
68 "Prison root can create raw sockets");
69
70 /* allprison, lastprid, and prisoncount are protected by allprison_mtx. */
71 struct prisonlist allprison;
72 struct mtx allprison_mtx;
73 int lastprid = 0;
74 int prisoncount = 0;
75
76 static void init_prison(void *);
77 static void prison_complete(void *context, int pending);
78 static struct prison *prison_find(int);
79 static int sysctl_jail_list(SYSCTL_HANDLER_ARGS);
80
81 static void
82 init_prison(void *data __unused)
83 {
84
85 mtx_init(&allprison_mtx, "allprison", NULL, MTX_DEF);
86 LIST_INIT(&allprison);
87 }
88
89 SYSINIT(prison, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_prison, NULL);
90
91 /*
92 * MPSAFE
93 *
94 * struct jail_args {
95 * struct jail *jail;
96 * };
97 */
98 int
99 jail(struct thread *td, struct jail_args *uap)
100 {
101 struct nameidata nd;
102 struct prison *pr, *tpr;
103 struct jail j;
104 struct jail_attach_args jaa;
105 int error, tryprid;
106
107 error = copyin(uap->jail, &j, sizeof(j));
108 if (error)
109 return (error);
110 if (j.version != 0)
111 return (EINVAL);
112
113 MALLOC(pr, struct prison *, sizeof(*pr), M_PRISON, M_WAITOK | M_ZERO);
114 mtx_init(&pr->pr_mtx, "jail mutex", NULL, MTX_DEF);
115 pr->pr_ref = 1;
116 error = copyinstr(j.path, &pr->pr_path, sizeof(pr->pr_path), 0);
117 if (error)
118 goto e_killmtx;
119 mtx_lock(&Giant);
120 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, pr->pr_path, td);
121 error = namei(&nd);
122 if (error) {
123 mtx_unlock(&Giant);
124 goto e_killmtx;
125 }
126 pr->pr_root = nd.ni_vp;
127 VOP_UNLOCK(nd.ni_vp, 0, td);
128 NDFREE(&nd, NDF_ONLY_PNBUF);
129 mtx_unlock(&Giant);
130 error = copyinstr(j.hostname, &pr->pr_host, sizeof(pr->pr_host), 0);
131 if (error)
132 goto e_dropvnref;
133 pr->pr_ip = j.ip_number;
134 pr->pr_linux = NULL;
135 pr->pr_securelevel = securelevel;
136
137 /* Determine next pr_id and add prison to allprison list. */
138 mtx_lock(&allprison_mtx);
139 tryprid = lastprid + 1;
140 if (tryprid == JAIL_MAX)
141 tryprid = 1;
142 next:
143 LIST_FOREACH(tpr, &allprison, pr_list) {
144 if (tpr->pr_id == tryprid) {
145 tryprid++;
146 if (tryprid == JAIL_MAX) {
147 mtx_unlock(&allprison_mtx);
148 error = EAGAIN;
149 goto e_dropvnref;
150 }
151 goto next;
152 }
153 }
154 pr->pr_id = jaa.jid = lastprid = tryprid;
155 LIST_INSERT_HEAD(&allprison, pr, pr_list);
156 prisoncount++;
157 mtx_unlock(&allprison_mtx);
158
159 error = jail_attach(td, &jaa);
160 if (error)
161 goto e_dropprref;
162 mtx_lock(&pr->pr_mtx);
163 pr->pr_ref--;
164 mtx_unlock(&pr->pr_mtx);
165 td->td_retval[0] = jaa.jid;
166 return (0);
167 e_dropprref:
168 mtx_lock(&allprison_mtx);
169 LIST_REMOVE(pr, pr_list);
170 prisoncount--;
171 mtx_unlock(&allprison_mtx);
172 e_dropvnref:
173 mtx_lock(&Giant);
174 vrele(pr->pr_root);
175 mtx_unlock(&Giant);
176 e_killmtx:
177 mtx_destroy(&pr->pr_mtx);
178 FREE(pr, M_PRISON);
179 return (error);
180 }
181
182 /*
183 * MPSAFE
184 *
185 * struct jail_attach_args {
186 * int jid;
187 * };
188 */
189 int
190 jail_attach(struct thread *td, struct jail_attach_args *uap)
191 {
192 struct proc *p;
193 struct ucred *newcred, *oldcred;
194 struct prison *pr;
195 int error;
196
197 /*
198 * XXX: Note that there is a slight race here if two threads
199 * in the same privileged process attempt to attach to two
200 * different jails at the same time. It is important for
201 * user processes not to do this, or they might end up with
202 * a process root from one prison, but attached to the jail
203 * of another.
204 */
205 error = suser(td);
206 if (error)
207 return (error);
208
209 p = td->td_proc;
210 mtx_lock(&allprison_mtx);
211 pr = prison_find(uap->jid);
212 if (pr == NULL) {
213 mtx_unlock(&allprison_mtx);
214 return (EINVAL);
215 }
216 pr->pr_ref++;
217 mtx_unlock(&pr->pr_mtx);
218 mtx_unlock(&allprison_mtx);
219
220 mtx_lock(&Giant);
221 vn_lock(pr->pr_root, LK_EXCLUSIVE | LK_RETRY, td);
222 if ((error = change_dir(pr->pr_root, td)) != 0)
223 goto e_unlock;
224 #ifdef MAC
225 if ((error = mac_check_vnode_chroot(td->td_ucred, pr->pr_root)))
226 goto e_unlock;
227 #endif
228 VOP_UNLOCK(pr->pr_root, 0, td);
229 change_root(pr->pr_root, td);
230 mtx_unlock(&Giant);
231
232 newcred = crget();
233 PROC_LOCK(p);
234 oldcred = p->p_ucred;
235 setsugid(p);
236 crcopy(newcred, oldcred);
237 newcred->cr_prison = pr;
238 p->p_ucred = newcred;
239 PROC_UNLOCK(p);
240 crfree(oldcred);
241 return (0);
242 e_unlock:
243 VOP_UNLOCK(pr->pr_root, 0, td);
244 mtx_unlock(&Giant);
245 mtx_lock(&pr->pr_mtx);
246 pr->pr_ref--;
247 mtx_unlock(&pr->pr_mtx);
248 return (error);
249 }
250
251 /*
252 * Returns a locked prison instance, or NULL on failure.
253 */
254 static struct prison *
255 prison_find(int prid)
256 {
257 struct prison *pr;
258
259 mtx_assert(&allprison_mtx, MA_OWNED);
260 LIST_FOREACH(pr, &allprison, pr_list) {
261 if (pr->pr_id == prid) {
262 mtx_lock(&pr->pr_mtx);
263 return (pr);
264 }
265 }
266 return (NULL);
267 }
268
269 void
270 prison_free(struct prison *pr)
271 {
272
273 mtx_lock(&allprison_mtx);
274 mtx_lock(&pr->pr_mtx);
275 pr->pr_ref--;
276 if (pr->pr_ref == 0) {
277 LIST_REMOVE(pr, pr_list);
278 mtx_unlock(&pr->pr_mtx);
279 prisoncount--;
280 mtx_unlock(&allprison_mtx);
281
282 TASK_INIT(&pr->pr_task, 0, prison_complete, pr);
283 taskqueue_enqueue(taskqueue_swi, &pr->pr_task);
284 return;
285 }
286 mtx_unlock(&pr->pr_mtx);
287 mtx_unlock(&allprison_mtx);
288 }
289
290 static void
291 prison_complete(void *context, int pending)
292 {
293 struct prison *pr;
294
295 pr = (struct prison *)context;
296
297 mtx_lock(&Giant);
298 vrele(pr->pr_root);
299 mtx_unlock(&Giant);
300
301 mtx_destroy(&pr->pr_mtx);
302 if (pr->pr_linux != NULL)
303 FREE(pr->pr_linux, M_PRISON);
304 FREE(pr, M_PRISON);
305 }
306
307 void
308 prison_hold(struct prison *pr)
309 {
310
311 mtx_lock(&pr->pr_mtx);
312 pr->pr_ref++;
313 mtx_unlock(&pr->pr_mtx);
314 }
315
316 u_int32_t
317 prison_getip(struct ucred *cred)
318 {
319
320 return (cred->cr_prison->pr_ip);
321 }
322
323 int
324 prison_ip(struct ucred *cred, int flag, u_int32_t *ip)
325 {
326 u_int32_t tmp;
327
328 if (!jailed(cred))
329 return (0);
330 if (flag)
331 tmp = *ip;
332 else
333 tmp = ntohl(*ip);
334 if (tmp == INADDR_ANY) {
335 if (flag)
336 *ip = cred->cr_prison->pr_ip;
337 else
338 *ip = htonl(cred->cr_prison->pr_ip);
339 return (0);
340 }
341 if (tmp == INADDR_LOOPBACK) {
342 if (flag)
343 *ip = cred->cr_prison->pr_ip;
344 else
345 *ip = htonl(cred->cr_prison->pr_ip);
346 return (0);
347 }
348 if (cred->cr_prison->pr_ip != tmp)
349 return (1);
350 return (0);
351 }
352
353 void
354 prison_remote_ip(struct ucred *cred, int flag, u_int32_t *ip)
355 {
356 u_int32_t tmp;
357
358 if (!jailed(cred))
359 return;
360 if (flag)
361 tmp = *ip;
362 else
363 tmp = ntohl(*ip);
364 if (tmp == INADDR_LOOPBACK) {
365 if (flag)
366 *ip = cred->cr_prison->pr_ip;
367 else
368 *ip = htonl(cred->cr_prison->pr_ip);
369 return;
370 }
371 return;
372 }
373
374 int
375 prison_if(struct ucred *cred, struct sockaddr *sa)
376 {
377 struct sockaddr_in *sai;
378 int ok;
379
380 sai = (struct sockaddr_in *)sa;
381 if ((sai->sin_family != AF_INET) && jail_socket_unixiproute_only)
382 ok = 1;
383 else if (sai->sin_family != AF_INET)
384 ok = 0;
385 else if (cred->cr_prison->pr_ip != ntohl(sai->sin_addr.s_addr))
386 ok = 1;
387 else
388 ok = 0;
389 return (ok);
390 }
391
392 /*
393 * Return 0 if jails permit p1 to frob p2, otherwise ESRCH.
394 */
395 int
396 prison_check(struct ucred *cred1, struct ucred *cred2)
397 {
398
399 if (jailed(cred1)) {
400 if (!jailed(cred2))
401 return (ESRCH);
402 if (cred2->cr_prison != cred1->cr_prison)
403 return (ESRCH);
404 }
405
406 return (0);
407 }
408
409 /*
410 * Return 1 if the passed credential is in a jail, otherwise 0.
411 */
412 int
413 jailed(struct ucred *cred)
414 {
415
416 return (cred->cr_prison != NULL);
417 }
418
419 /*
420 * Return the correct hostname for the passed credential.
421 */
422 void
423 getcredhostname(struct ucred *cred, char *buf, size_t size)
424 {
425
426 if (jailed(cred)) {
427 mtx_lock(&cred->cr_prison->pr_mtx);
428 strlcpy(buf, cred->cr_prison->pr_host, size);
429 mtx_unlock(&cred->cr_prison->pr_mtx);
430 } else
431 strlcpy(buf, hostname, size);
432 }
433
434 /*
435 * Return 1 if the passed credential can "see" the passed mountpoint
436 * when performing a getfsstat(); otherwise, 0.
437 */
438 int
439 prison_check_mount(struct ucred *cred, struct mount *mp)
440 {
441
442 if (jail_getfsstatroot_only && cred->cr_prison != NULL) {
443 if (cred->cr_prison->pr_root->v_mount != mp)
444 return (0);
445 }
446 return (1);
447 }
448
449 static int
450 sysctl_jail_list(SYSCTL_HANDLER_ARGS)
451 {
452 struct xprison *xp, *sxp;
453 struct prison *pr;
454 int count, error;
455
456 mtx_assert(&Giant, MA_OWNED);
457 if (jailed(req->td->td_ucred))
458 return (0);
459 retry:
460 mtx_lock(&allprison_mtx);
461 count = prisoncount;
462 mtx_unlock(&allprison_mtx);
463
464 if (count == 0)
465 return (0);
466
467 sxp = xp = malloc(sizeof(*xp) * count, M_TEMP, M_WAITOK | M_ZERO);
468 mtx_lock(&allprison_mtx);
469 if (count != prisoncount) {
470 mtx_unlock(&allprison_mtx);
471 free(sxp, M_TEMP);
472 goto retry;
473 }
474
475 LIST_FOREACH(pr, &allprison, pr_list) {
476 mtx_lock(&pr->pr_mtx);
477 xp->pr_version = XPRISON_VERSION;
478 xp->pr_id = pr->pr_id;
479 strlcpy(xp->pr_path, pr->pr_path, sizeof(xp->pr_path));
480 strlcpy(xp->pr_host, pr->pr_host, sizeof(xp->pr_host));
481 xp->pr_ip = pr->pr_ip;
482 mtx_unlock(&pr->pr_mtx);
483 xp++;
484 }
485 mtx_unlock(&allprison_mtx);
486
487 error = SYSCTL_OUT(req, sxp, sizeof(*sxp) * count);
488 free(sxp, M_TEMP);
489 if (error)
490 return (error);
491 return (0);
492 }
493
494 SYSCTL_OID(_security_jail, OID_AUTO, list, CTLTYPE_STRUCT | CTLFLAG_RD,
495 NULL, 0, sysctl_jail_list, "S", "List of active jails");
496
497 static int
498 sysctl_jail_jailed(SYSCTL_HANDLER_ARGS)
499 {
500 int error, injail;
501
502 injail = jailed(req->td->td_ucred);
503 error = SYSCTL_OUT(req, &injail, sizeof(injail));
504
505 return (error);
506 }
507 SYSCTL_PROC(_security_jail, OID_AUTO, jailed, CTLTYPE_INT | CTLFLAG_RD,
508 NULL, 0, sysctl_jail_jailed, "I", "Process in jail?");
Cache object: 0653379a40c38480bdb479574e388664
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