1 /*-
2 * Copyright (c) 1999-2002, 2007-2008 Robert N. M. Watson
3 * Copyright (c) 2001-2005 Networks Associates Technology, Inc.
4 * Copyright (c) 2005 Tom Rhodes
5 * Copyright (c) 2006 SPARTA, Inc.
6 * All rights reserved.
7 *
8 * This software was developed by Robert Watson for the TrustedBSD Project.
9 * It was later enhanced by Tom Rhodes for the TrustedBSD Project.
10 *
11 * This software was developed for the FreeBSD Project in part by Network
12 * Associates Laboratories, the Security Research Division of Network
13 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
14 * as part of the DARPA CHATS research program.
15 *
16 * This software was enhanced by SPARTA ISSO under SPAWAR contract
17 * N66001-04-C-6019 ("SEFOS").
18 *
19 * Redistribution and use in source and binary forms, with or without
20 * modification, are permitted provided that the following conditions
21 * are met:
22 * 1. Redistributions of source code must retain the above copyright
23 * notice, this list of conditions and the following disclaimer.
24 * 2. Redistributions in binary form must reproduce the above copyright
25 * notice, this list of conditions and the following disclaimer in the
26 * documentation and/or other materials provided with the distribution.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 * $FreeBSD$
41 */
42
43 /*
44 * Developed by the TrustedBSD Project.
45 *
46 * "BSD Extended" MAC policy, allowing the administrator to impose mandatory
47 * firewall-like rules regarding users and file system objects.
48 */
49
50 #include <sys/param.h>
51 #include <sys/acl.h>
52 #include <sys/kernel.h>
53 #include <sys/jail.h>
54 #include <sys/lock.h>
55 #include <sys/malloc.h>
56 #include <sys/module.h>
57 #include <sys/mount.h>
58 #include <sys/mutex.h>
59 #include <sys/priv.h>
60 #include <sys/proc.h>
61 #include <sys/systm.h>
62 #include <sys/vnode.h>
63 #include <sys/sysctl.h>
64 #include <sys/syslog.h>
65 #include <sys/stat.h>
66
67 #include <security/mac/mac_policy.h>
68 #include <security/mac_bsdextended/mac_bsdextended.h>
69 #include <security/mac_bsdextended/ugidfw_internal.h>
70
71 static struct mtx ugidfw_mtx;
72
73 SYSCTL_DECL(_security_mac);
74
75 static SYSCTL_NODE(_security_mac, OID_AUTO, bsdextended,
76 CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
77 "TrustedBSD extended BSD MAC policy controls");
78
79 static int ugidfw_enabled = 1;
80 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, enabled, CTLFLAG_RWTUN,
81 &ugidfw_enabled, 0, "Enforce extended BSD policy");
82
83 static MALLOC_DEFINE(M_MACBSDEXTENDED, "mac_bsdextended",
84 "BSD Extended MAC rule");
85
86 #define MAC_BSDEXTENDED_MAXRULES 250
87 static struct mac_bsdextended_rule *rules[MAC_BSDEXTENDED_MAXRULES];
88 static int rule_count = 0;
89 static int rule_slots = 0;
90 static int rule_version = MB_VERSION;
91
92 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, rule_count, CTLFLAG_RD,
93 &rule_count, 0, "Number of defined rules\n");
94 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, rule_slots, CTLFLAG_RD,
95 &rule_slots, 0, "Number of used rule slots\n");
96 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, rule_version, CTLFLAG_RD,
97 &rule_version, 0, "Version number for API\n");
98
99 /*
100 * This is just used for logging purposes, eventually we would like to log
101 * much more then failed requests.
102 */
103 static int ugidfw_logging;
104 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, logging, CTLFLAG_RW,
105 &ugidfw_logging, 0, "Log failed authorization requests");
106
107 /*
108 * This tunable is here for compatibility. It will allow the user to switch
109 * between the new mode (first rule matches) and the old functionality (all
110 * rules match).
111 */
112 static int ugidfw_firstmatch_enabled;
113 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, firstmatch_enabled,
114 CTLFLAG_RW, &ugidfw_firstmatch_enabled, 1,
115 "Disable/enable match first rule functionality");
116
117 static int
118 ugidfw_rule_valid(struct mac_bsdextended_rule *rule)
119 {
120
121 if ((rule->mbr_subject.mbs_flags | MBS_ALL_FLAGS) != MBS_ALL_FLAGS)
122 return (EINVAL);
123 if ((rule->mbr_subject.mbs_neg | MBS_ALL_FLAGS) != MBS_ALL_FLAGS)
124 return (EINVAL);
125 if ((rule->mbr_object.mbo_flags | MBO_ALL_FLAGS) != MBO_ALL_FLAGS)
126 return (EINVAL);
127 if ((rule->mbr_object.mbo_neg | MBO_ALL_FLAGS) != MBO_ALL_FLAGS)
128 return (EINVAL);
129 if (((rule->mbr_object.mbo_flags & MBO_TYPE_DEFINED) != 0) &&
130 (rule->mbr_object.mbo_type | MBO_ALL_TYPE) != MBO_ALL_TYPE)
131 return (EINVAL);
132 if ((rule->mbr_mode | MBI_ALLPERM) != MBI_ALLPERM)
133 return (EINVAL);
134 return (0);
135 }
136
137 static int
138 sysctl_rule(SYSCTL_HANDLER_ARGS)
139 {
140 struct mac_bsdextended_rule temprule, *ruleptr;
141 u_int namelen;
142 int error, index, *name;
143
144 error = 0;
145 name = (int *)arg1;
146 namelen = arg2;
147 if (namelen != 1)
148 return (EINVAL);
149 index = name[0];
150 if (index >= MAC_BSDEXTENDED_MAXRULES)
151 return (ENOENT);
152
153 ruleptr = NULL;
154 if (req->newptr && req->newlen != 0) {
155 error = SYSCTL_IN(req, &temprule, sizeof(temprule));
156 if (error)
157 return (error);
158 ruleptr = malloc(sizeof(*ruleptr), M_MACBSDEXTENDED,
159 M_WAITOK | M_ZERO);
160 }
161
162 mtx_lock(&ugidfw_mtx);
163 if (req->oldptr) {
164 if (index < 0 || index > rule_slots + 1) {
165 error = ENOENT;
166 goto out;
167 }
168 if (rules[index] == NULL) {
169 error = ENOENT;
170 goto out;
171 }
172 temprule = *rules[index];
173 }
174 if (req->newptr && req->newlen == 0) {
175 KASSERT(ruleptr == NULL, ("sysctl_rule: ruleptr != NULL"));
176 ruleptr = rules[index];
177 if (ruleptr == NULL) {
178 error = ENOENT;
179 goto out;
180 }
181 rule_count--;
182 rules[index] = NULL;
183 } else if (req->newptr) {
184 error = ugidfw_rule_valid(&temprule);
185 if (error)
186 goto out;
187 if (rules[index] == NULL) {
188 *ruleptr = temprule;
189 rules[index] = ruleptr;
190 ruleptr = NULL;
191 if (index + 1 > rule_slots)
192 rule_slots = index + 1;
193 rule_count++;
194 } else
195 *rules[index] = temprule;
196 }
197 out:
198 mtx_unlock(&ugidfw_mtx);
199 if (ruleptr != NULL)
200 free(ruleptr, M_MACBSDEXTENDED);
201 if (req->oldptr && error == 0)
202 error = SYSCTL_OUT(req, &temprule, sizeof(temprule));
203 return (error);
204 }
205
206 static SYSCTL_NODE(_security_mac_bsdextended, OID_AUTO, rules,
207 CTLFLAG_MPSAFE | CTLFLAG_RW, sysctl_rule, "BSD extended MAC rules");
208
209 static void
210 ugidfw_init(struct mac_policy_conf *mpc)
211 {
212
213 mtx_init(&ugidfw_mtx, "mac_bsdextended lock", NULL, MTX_DEF);
214 }
215
216 static void
217 ugidfw_destroy(struct mac_policy_conf *mpc)
218 {
219 int i;
220
221 for (i = 0; i < MAC_BSDEXTENDED_MAXRULES; i++) {
222 if (rules[i] != NULL)
223 free(rules[i], M_MACBSDEXTENDED);
224 }
225 mtx_destroy(&ugidfw_mtx);
226 }
227
228 static int
229 ugidfw_rulecheck(struct mac_bsdextended_rule *rule,
230 struct ucred *cred, struct vnode *vp, struct vattr *vap, int acc_mode)
231 {
232 int mac_granted, match, priv_granted;
233 int i;
234
235 /*
236 * Is there a subject match?
237 */
238 mtx_assert(&ugidfw_mtx, MA_OWNED);
239 if (rule->mbr_subject.mbs_flags & MBS_UID_DEFINED) {
240 match = ((cred->cr_uid <= rule->mbr_subject.mbs_uid_max &&
241 cred->cr_uid >= rule->mbr_subject.mbs_uid_min) ||
242 (cred->cr_ruid <= rule->mbr_subject.mbs_uid_max &&
243 cred->cr_ruid >= rule->mbr_subject.mbs_uid_min) ||
244 (cred->cr_svuid <= rule->mbr_subject.mbs_uid_max &&
245 cred->cr_svuid >= rule->mbr_subject.mbs_uid_min));
246 if (rule->mbr_subject.mbs_neg & MBS_UID_DEFINED)
247 match = !match;
248 if (!match)
249 return (0);
250 }
251
252 if (rule->mbr_subject.mbs_flags & MBS_GID_DEFINED) {
253 match = ((cred->cr_rgid <= rule->mbr_subject.mbs_gid_max &&
254 cred->cr_rgid >= rule->mbr_subject.mbs_gid_min) ||
255 (cred->cr_svgid <= rule->mbr_subject.mbs_gid_max &&
256 cred->cr_svgid >= rule->mbr_subject.mbs_gid_min));
257 if (!match) {
258 for (i = 0; i < cred->cr_ngroups; i++) {
259 if (cred->cr_groups[i]
260 <= rule->mbr_subject.mbs_gid_max &&
261 cred->cr_groups[i]
262 >= rule->mbr_subject.mbs_gid_min) {
263 match = 1;
264 break;
265 }
266 }
267 }
268 if (rule->mbr_subject.mbs_neg & MBS_GID_DEFINED)
269 match = !match;
270 if (!match)
271 return (0);
272 }
273
274 if (rule->mbr_subject.mbs_flags & MBS_PRISON_DEFINED) {
275 match =
276 (cred->cr_prison->pr_id == rule->mbr_subject.mbs_prison);
277 if (rule->mbr_subject.mbs_neg & MBS_PRISON_DEFINED)
278 match = !match;
279 if (!match)
280 return (0);
281 }
282
283 /*
284 * Is there an object match?
285 */
286 if (rule->mbr_object.mbo_flags & MBO_UID_DEFINED) {
287 match = (vap->va_uid <= rule->mbr_object.mbo_uid_max &&
288 vap->va_uid >= rule->mbr_object.mbo_uid_min);
289 if (rule->mbr_object.mbo_neg & MBO_UID_DEFINED)
290 match = !match;
291 if (!match)
292 return (0);
293 }
294
295 if (rule->mbr_object.mbo_flags & MBO_GID_DEFINED) {
296 match = (vap->va_gid <= rule->mbr_object.mbo_gid_max &&
297 vap->va_gid >= rule->mbr_object.mbo_gid_min);
298 if (rule->mbr_object.mbo_neg & MBO_GID_DEFINED)
299 match = !match;
300 if (!match)
301 return (0);
302 }
303
304 if (rule->mbr_object.mbo_flags & MBO_FSID_DEFINED) {
305 match = (fsidcmp(&vp->v_mount->mnt_stat.f_fsid,
306 &rule->mbr_object.mbo_fsid) == 0);
307 if (rule->mbr_object.mbo_neg & MBO_FSID_DEFINED)
308 match = !match;
309 if (!match)
310 return (0);
311 }
312
313 if (rule->mbr_object.mbo_flags & MBO_SUID) {
314 match = (vap->va_mode & S_ISUID);
315 if (rule->mbr_object.mbo_neg & MBO_SUID)
316 match = !match;
317 if (!match)
318 return (0);
319 }
320
321 if (rule->mbr_object.mbo_flags & MBO_SGID) {
322 match = (vap->va_mode & S_ISGID);
323 if (rule->mbr_object.mbo_neg & MBO_SGID)
324 match = !match;
325 if (!match)
326 return (0);
327 }
328
329 if (rule->mbr_object.mbo_flags & MBO_UID_SUBJECT) {
330 match = (vap->va_uid == cred->cr_uid ||
331 vap->va_uid == cred->cr_ruid ||
332 vap->va_uid == cred->cr_svuid);
333 if (rule->mbr_object.mbo_neg & MBO_UID_SUBJECT)
334 match = !match;
335 if (!match)
336 return (0);
337 }
338
339 if (rule->mbr_object.mbo_flags & MBO_GID_SUBJECT) {
340 match = (groupmember(vap->va_gid, cred) ||
341 vap->va_gid == cred->cr_rgid ||
342 vap->va_gid == cred->cr_svgid);
343 if (rule->mbr_object.mbo_neg & MBO_GID_SUBJECT)
344 match = !match;
345 if (!match)
346 return (0);
347 }
348
349 if (rule->mbr_object.mbo_flags & MBO_TYPE_DEFINED) {
350 switch (vap->va_type) {
351 case VREG:
352 match = (rule->mbr_object.mbo_type & MBO_TYPE_REG);
353 break;
354 case VDIR:
355 match = (rule->mbr_object.mbo_type & MBO_TYPE_DIR);
356 break;
357 case VBLK:
358 match = (rule->mbr_object.mbo_type & MBO_TYPE_BLK);
359 break;
360 case VCHR:
361 match = (rule->mbr_object.mbo_type & MBO_TYPE_CHR);
362 break;
363 case VLNK:
364 match = (rule->mbr_object.mbo_type & MBO_TYPE_LNK);
365 break;
366 case VSOCK:
367 match = (rule->mbr_object.mbo_type & MBO_TYPE_SOCK);
368 break;
369 case VFIFO:
370 match = (rule->mbr_object.mbo_type & MBO_TYPE_FIFO);
371 break;
372 default:
373 match = 0;
374 }
375 if (rule->mbr_object.mbo_neg & MBO_TYPE_DEFINED)
376 match = !match;
377 if (!match)
378 return (0);
379 }
380
381 /*
382 * MBI_APPEND should not be here as it should get converted to
383 * MBI_WRITE.
384 */
385 priv_granted = 0;
386 mac_granted = rule->mbr_mode;
387 if ((acc_mode & MBI_ADMIN) && (mac_granted & MBI_ADMIN) == 0 &&
388 priv_check_cred(cred, PRIV_VFS_ADMIN) == 0)
389 priv_granted |= MBI_ADMIN;
390 if ((acc_mode & MBI_EXEC) && (mac_granted & MBI_EXEC) == 0 &&
391 priv_check_cred(cred, (vap->va_type == VDIR) ? PRIV_VFS_LOOKUP : PRIV_VFS_EXEC) == 0)
392 priv_granted |= MBI_EXEC;
393 if ((acc_mode & MBI_READ) && (mac_granted & MBI_READ) == 0 &&
394 priv_check_cred(cred, PRIV_VFS_READ) == 0)
395 priv_granted |= MBI_READ;
396 if ((acc_mode & MBI_STAT) && (mac_granted & MBI_STAT) == 0 &&
397 priv_check_cred(cred, PRIV_VFS_STAT) == 0)
398 priv_granted |= MBI_STAT;
399 if ((acc_mode & MBI_WRITE) && (mac_granted & MBI_WRITE) == 0 &&
400 priv_check_cred(cred, PRIV_VFS_WRITE) == 0)
401 priv_granted |= MBI_WRITE;
402 /*
403 * Is the access permitted?
404 */
405 if (((mac_granted | priv_granted) & acc_mode) != acc_mode) {
406 if (ugidfw_logging)
407 log(LOG_AUTHPRIV, "mac_bsdextended: %d:%d request %d"
408 " on %d:%d failed. \n", cred->cr_ruid,
409 cred->cr_rgid, acc_mode, vap->va_uid,
410 vap->va_gid);
411 return (EACCES);
412 }
413
414 /*
415 * If the rule matched, permits access, and first match is enabled,
416 * return success.
417 */
418 if (ugidfw_firstmatch_enabled)
419 return (EJUSTRETURN);
420 else
421 return (0);
422 }
423
424 int
425 ugidfw_check(struct ucred *cred, struct vnode *vp, struct vattr *vap,
426 int acc_mode)
427 {
428 int error, i;
429
430 /*
431 * Since we do not separately handle append, map append to write.
432 */
433 if (acc_mode & MBI_APPEND) {
434 acc_mode &= ~MBI_APPEND;
435 acc_mode |= MBI_WRITE;
436 }
437 mtx_lock(&ugidfw_mtx);
438 for (i = 0; i < rule_slots; i++) {
439 if (rules[i] == NULL)
440 continue;
441 error = ugidfw_rulecheck(rules[i], cred,
442 vp, vap, acc_mode);
443 if (error == EJUSTRETURN)
444 break;
445 if (error) {
446 mtx_unlock(&ugidfw_mtx);
447 return (error);
448 }
449 }
450 mtx_unlock(&ugidfw_mtx);
451 return (0);
452 }
453
454 int
455 ugidfw_check_vp(struct ucred *cred, struct vnode *vp, int acc_mode)
456 {
457 int error;
458 struct vattr vap;
459
460 if (!ugidfw_enabled)
461 return (0);
462 error = VOP_GETATTR(vp, &vap, cred);
463 if (error)
464 return (error);
465 return (ugidfw_check(cred, vp, &vap, acc_mode));
466 }
467
468 int
469 ugidfw_accmode2mbi(accmode_t accmode)
470 {
471 int mbi;
472
473 mbi = 0;
474 if (accmode & VEXEC)
475 mbi |= MBI_EXEC;
476 if (accmode & VWRITE)
477 mbi |= MBI_WRITE;
478 if (accmode & VREAD)
479 mbi |= MBI_READ;
480 if (accmode & VADMIN_PERMS)
481 mbi |= MBI_ADMIN;
482 if (accmode & VSTAT_PERMS)
483 mbi |= MBI_STAT;
484 if (accmode & VAPPEND)
485 mbi |= MBI_APPEND;
486 return (mbi);
487 }
488
489 static struct mac_policy_ops ugidfw_ops =
490 {
491 .mpo_destroy = ugidfw_destroy,
492 .mpo_init = ugidfw_init,
493 .mpo_system_check_acct = ugidfw_system_check_acct,
494 .mpo_system_check_auditctl = ugidfw_system_check_auditctl,
495 .mpo_system_check_swapon = ugidfw_system_check_swapon,
496 .mpo_vnode_check_access = ugidfw_vnode_check_access,
497 .mpo_vnode_check_chdir = ugidfw_vnode_check_chdir,
498 .mpo_vnode_check_chroot = ugidfw_vnode_check_chroot,
499 .mpo_vnode_check_create = ugidfw_check_create_vnode,
500 .mpo_vnode_check_deleteacl = ugidfw_vnode_check_deleteacl,
501 .mpo_vnode_check_deleteextattr = ugidfw_vnode_check_deleteextattr,
502 .mpo_vnode_check_exec = ugidfw_vnode_check_exec,
503 .mpo_vnode_check_getacl = ugidfw_vnode_check_getacl,
504 .mpo_vnode_check_getextattr = ugidfw_vnode_check_getextattr,
505 .mpo_vnode_check_link = ugidfw_vnode_check_link,
506 .mpo_vnode_check_listextattr = ugidfw_vnode_check_listextattr,
507 .mpo_vnode_check_lookup = ugidfw_vnode_check_lookup,
508 .mpo_vnode_check_open = ugidfw_vnode_check_open,
509 .mpo_vnode_check_readdir = ugidfw_vnode_check_readdir,
510 .mpo_vnode_check_readlink = ugidfw_vnode_check_readdlink,
511 .mpo_vnode_check_rename_from = ugidfw_vnode_check_rename_from,
512 .mpo_vnode_check_rename_to = ugidfw_vnode_check_rename_to,
513 .mpo_vnode_check_revoke = ugidfw_vnode_check_revoke,
514 .mpo_vnode_check_setacl = ugidfw_check_setacl_vnode,
515 .mpo_vnode_check_setextattr = ugidfw_vnode_check_setextattr,
516 .mpo_vnode_check_setflags = ugidfw_vnode_check_setflags,
517 .mpo_vnode_check_setmode = ugidfw_vnode_check_setmode,
518 .mpo_vnode_check_setowner = ugidfw_vnode_check_setowner,
519 .mpo_vnode_check_setutimes = ugidfw_vnode_check_setutimes,
520 .mpo_vnode_check_stat = ugidfw_vnode_check_stat,
521 .mpo_vnode_check_unlink = ugidfw_vnode_check_unlink,
522 };
523
524 MAC_POLICY_SET(&ugidfw_ops, mac_bsdextended, "TrustedBSD MAC/BSD Extended",
525 MPC_LOADTIME_FLAG_UNLOADOK, NULL);
Cache object: 5663d743e931fb7bec7a135cbaeb3792
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