FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_prot.c
1 /*-
2 * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993
3 * The Regents of the University of California.
4 * (c) UNIX System Laboratories, Inc.
5 * Copyright (c) 2000-2001 Robert N. M. Watson.
6 * All rights reserved.
7 *
8 * All or some portions of this file are derived from material licensed
9 * to the University of California by American Telephone and Telegraph
10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11 * the permission of UNIX System Laboratories, Inc.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * @(#)kern_prot.c 8.6 (Berkeley) 1/21/94
38 */
39
40 /*
41 * System calls related to processes and protection
42 */
43
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD: releng/9.1/sys/kern/kern_prot.c 274112 2014-11-04 23:32:45Z des $");
46
47 #include "opt_compat.h"
48 #include "opt_inet.h"
49 #include "opt_inet6.h"
50
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/acct.h>
54 #include <sys/kdb.h>
55 #include <sys/kernel.h>
56 #include <sys/lock.h>
57 #include <sys/loginclass.h>
58 #include <sys/malloc.h>
59 #include <sys/mutex.h>
60 #include <sys/refcount.h>
61 #include <sys/sx.h>
62 #include <sys/priv.h>
63 #include <sys/proc.h>
64 #include <sys/sysproto.h>
65 #include <sys/jail.h>
66 #include <sys/pioctl.h>
67 #include <sys/racct.h>
68 #include <sys/resourcevar.h>
69 #include <sys/socket.h>
70 #include <sys/socketvar.h>
71 #include <sys/syscallsubr.h>
72 #include <sys/sysctl.h>
73
74 #ifdef REGRESSION
75 FEATURE(regression,
76 "Kernel support for interfaces nessesary for regression testing (SECURITY RISK!)");
77 #endif
78
79 #if defined(INET) || defined(INET6)
80 #include <netinet/in.h>
81 #include <netinet/in_pcb.h>
82 #endif
83
84 #include <security/audit/audit.h>
85 #include <security/mac/mac_framework.h>
86
87 static MALLOC_DEFINE(M_CRED, "cred", "credentials");
88
89 SYSCTL_NODE(_security, OID_AUTO, bsd, CTLFLAG_RW, 0, "BSD security policy");
90
91 static void crextend(struct ucred *cr, int n);
92 static void crsetgroups_locked(struct ucred *cr, int ngrp,
93 gid_t *groups);
94
95 #ifndef _SYS_SYSPROTO_H_
96 struct getpid_args {
97 int dummy;
98 };
99 #endif
100 /* ARGSUSED */
101 int
102 sys_getpid(struct thread *td, struct getpid_args *uap)
103 {
104 struct proc *p = td->td_proc;
105
106 td->td_retval[0] = p->p_pid;
107 #if defined(COMPAT_43)
108 PROC_LOCK(p);
109 td->td_retval[1] = p->p_pptr->p_pid;
110 PROC_UNLOCK(p);
111 #endif
112 return (0);
113 }
114
115 #ifndef _SYS_SYSPROTO_H_
116 struct getppid_args {
117 int dummy;
118 };
119 #endif
120 /* ARGSUSED */
121 int
122 sys_getppid(struct thread *td, struct getppid_args *uap)
123 {
124 struct proc *p = td->td_proc;
125
126 PROC_LOCK(p);
127 td->td_retval[0] = p->p_pptr->p_pid;
128 PROC_UNLOCK(p);
129 return (0);
130 }
131
132 /*
133 * Get process group ID; note that POSIX getpgrp takes no parameter.
134 */
135 #ifndef _SYS_SYSPROTO_H_
136 struct getpgrp_args {
137 int dummy;
138 };
139 #endif
140 int
141 sys_getpgrp(struct thread *td, struct getpgrp_args *uap)
142 {
143 struct proc *p = td->td_proc;
144
145 PROC_LOCK(p);
146 td->td_retval[0] = p->p_pgrp->pg_id;
147 PROC_UNLOCK(p);
148 return (0);
149 }
150
151 /* Get an arbitary pid's process group id */
152 #ifndef _SYS_SYSPROTO_H_
153 struct getpgid_args {
154 pid_t pid;
155 };
156 #endif
157 int
158 sys_getpgid(struct thread *td, struct getpgid_args *uap)
159 {
160 struct proc *p;
161 int error;
162
163 if (uap->pid == 0) {
164 p = td->td_proc;
165 PROC_LOCK(p);
166 } else {
167 p = pfind(uap->pid);
168 if (p == NULL)
169 return (ESRCH);
170 error = p_cansee(td, p);
171 if (error) {
172 PROC_UNLOCK(p);
173 return (error);
174 }
175 }
176 td->td_retval[0] = p->p_pgrp->pg_id;
177 PROC_UNLOCK(p);
178 return (0);
179 }
180
181 /*
182 * Get an arbitary pid's session id.
183 */
184 #ifndef _SYS_SYSPROTO_H_
185 struct getsid_args {
186 pid_t pid;
187 };
188 #endif
189 int
190 sys_getsid(struct thread *td, struct getsid_args *uap)
191 {
192 struct proc *p;
193 int error;
194
195 if (uap->pid == 0) {
196 p = td->td_proc;
197 PROC_LOCK(p);
198 } else {
199 p = pfind(uap->pid);
200 if (p == NULL)
201 return (ESRCH);
202 error = p_cansee(td, p);
203 if (error) {
204 PROC_UNLOCK(p);
205 return (error);
206 }
207 }
208 td->td_retval[0] = p->p_session->s_sid;
209 PROC_UNLOCK(p);
210 return (0);
211 }
212
213 #ifndef _SYS_SYSPROTO_H_
214 struct getuid_args {
215 int dummy;
216 };
217 #endif
218 /* ARGSUSED */
219 int
220 sys_getuid(struct thread *td, struct getuid_args *uap)
221 {
222
223 td->td_retval[0] = td->td_ucred->cr_ruid;
224 #if defined(COMPAT_43)
225 td->td_retval[1] = td->td_ucred->cr_uid;
226 #endif
227 return (0);
228 }
229
230 #ifndef _SYS_SYSPROTO_H_
231 struct geteuid_args {
232 int dummy;
233 };
234 #endif
235 /* ARGSUSED */
236 int
237 sys_geteuid(struct thread *td, struct geteuid_args *uap)
238 {
239
240 td->td_retval[0] = td->td_ucred->cr_uid;
241 return (0);
242 }
243
244 #ifndef _SYS_SYSPROTO_H_
245 struct getgid_args {
246 int dummy;
247 };
248 #endif
249 /* ARGSUSED */
250 int
251 sys_getgid(struct thread *td, struct getgid_args *uap)
252 {
253
254 td->td_retval[0] = td->td_ucred->cr_rgid;
255 #if defined(COMPAT_43)
256 td->td_retval[1] = td->td_ucred->cr_groups[0];
257 #endif
258 return (0);
259 }
260
261 /*
262 * Get effective group ID. The "egid" is groups[0], and could be obtained
263 * via getgroups. This syscall exists because it is somewhat painful to do
264 * correctly in a library function.
265 */
266 #ifndef _SYS_SYSPROTO_H_
267 struct getegid_args {
268 int dummy;
269 };
270 #endif
271 /* ARGSUSED */
272 int
273 sys_getegid(struct thread *td, struct getegid_args *uap)
274 {
275
276 td->td_retval[0] = td->td_ucred->cr_groups[0];
277 return (0);
278 }
279
280 #ifndef _SYS_SYSPROTO_H_
281 struct getgroups_args {
282 u_int gidsetsize;
283 gid_t *gidset;
284 };
285 #endif
286 int
287 sys_getgroups(struct thread *td, register struct getgroups_args *uap)
288 {
289 gid_t *groups;
290 u_int ngrp;
291 int error;
292
293 if (uap->gidsetsize < td->td_ucred->cr_ngroups) {
294 if (uap->gidsetsize == 0)
295 ngrp = 0;
296 else
297 return (EINVAL);
298 } else
299 ngrp = td->td_ucred->cr_ngroups;
300 groups = malloc(ngrp * sizeof(*groups), M_TEMP, M_WAITOK);
301 error = kern_getgroups(td, &ngrp, groups);
302 if (error)
303 goto out;
304 if (uap->gidsetsize > 0)
305 error = copyout(groups, uap->gidset, ngrp * sizeof(gid_t));
306 if (error == 0)
307 td->td_retval[0] = ngrp;
308 out:
309 free(groups, M_TEMP);
310 return (error);
311 }
312
313 int
314 kern_getgroups(struct thread *td, u_int *ngrp, gid_t *groups)
315 {
316 struct ucred *cred;
317
318 cred = td->td_ucred;
319 if (*ngrp == 0) {
320 *ngrp = cred->cr_ngroups;
321 return (0);
322 }
323 if (*ngrp < cred->cr_ngroups)
324 return (EINVAL);
325 *ngrp = cred->cr_ngroups;
326 bcopy(cred->cr_groups, groups, *ngrp * sizeof(gid_t));
327 return (0);
328 }
329
330 #ifndef _SYS_SYSPROTO_H_
331 struct setsid_args {
332 int dummy;
333 };
334 #endif
335 /* ARGSUSED */
336 int
337 sys_setsid(register struct thread *td, struct setsid_args *uap)
338 {
339 struct pgrp *pgrp;
340 int error;
341 struct proc *p = td->td_proc;
342 struct pgrp *newpgrp;
343 struct session *newsess;
344
345 error = 0;
346 pgrp = NULL;
347
348 newpgrp = malloc(sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
349 newsess = malloc(sizeof(struct session), M_SESSION, M_WAITOK | M_ZERO);
350
351 sx_xlock(&proctree_lock);
352
353 if (p->p_pgid == p->p_pid || (pgrp = pgfind(p->p_pid)) != NULL) {
354 if (pgrp != NULL)
355 PGRP_UNLOCK(pgrp);
356 error = EPERM;
357 } else {
358 (void)enterpgrp(p, p->p_pid, newpgrp, newsess);
359 td->td_retval[0] = p->p_pid;
360 newpgrp = NULL;
361 newsess = NULL;
362 }
363
364 sx_xunlock(&proctree_lock);
365
366 if (newpgrp != NULL)
367 free(newpgrp, M_PGRP);
368 if (newsess != NULL)
369 free(newsess, M_SESSION);
370
371 return (error);
372 }
373
374 /*
375 * set process group (setpgid/old setpgrp)
376 *
377 * caller does setpgid(targpid, targpgid)
378 *
379 * pid must be caller or child of caller (ESRCH)
380 * if a child
381 * pid must be in same session (EPERM)
382 * pid can't have done an exec (EACCES)
383 * if pgid != pid
384 * there must exist some pid in same session having pgid (EPERM)
385 * pid must not be session leader (EPERM)
386 */
387 #ifndef _SYS_SYSPROTO_H_
388 struct setpgid_args {
389 int pid; /* target process id */
390 int pgid; /* target pgrp id */
391 };
392 #endif
393 /* ARGSUSED */
394 int
395 sys_setpgid(struct thread *td, register struct setpgid_args *uap)
396 {
397 struct proc *curp = td->td_proc;
398 register struct proc *targp; /* target process */
399 register struct pgrp *pgrp; /* target pgrp */
400 int error;
401 struct pgrp *newpgrp;
402
403 if (uap->pgid < 0)
404 return (EINVAL);
405
406 error = 0;
407
408 newpgrp = malloc(sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
409
410 sx_xlock(&proctree_lock);
411 if (uap->pid != 0 && uap->pid != curp->p_pid) {
412 if ((targp = pfind(uap->pid)) == NULL) {
413 error = ESRCH;
414 goto done;
415 }
416 if (!inferior(targp)) {
417 PROC_UNLOCK(targp);
418 error = ESRCH;
419 goto done;
420 }
421 if ((error = p_cansee(td, targp))) {
422 PROC_UNLOCK(targp);
423 goto done;
424 }
425 if (targp->p_pgrp == NULL ||
426 targp->p_session != curp->p_session) {
427 PROC_UNLOCK(targp);
428 error = EPERM;
429 goto done;
430 }
431 if (targp->p_flag & P_EXEC) {
432 PROC_UNLOCK(targp);
433 error = EACCES;
434 goto done;
435 }
436 PROC_UNLOCK(targp);
437 } else
438 targp = curp;
439 if (SESS_LEADER(targp)) {
440 error = EPERM;
441 goto done;
442 }
443 if (uap->pgid == 0)
444 uap->pgid = targp->p_pid;
445 if ((pgrp = pgfind(uap->pgid)) == NULL) {
446 if (uap->pgid == targp->p_pid) {
447 error = enterpgrp(targp, uap->pgid, newpgrp,
448 NULL);
449 if (error == 0)
450 newpgrp = NULL;
451 } else
452 error = EPERM;
453 } else {
454 if (pgrp == targp->p_pgrp) {
455 PGRP_UNLOCK(pgrp);
456 goto done;
457 }
458 if (pgrp->pg_id != targp->p_pid &&
459 pgrp->pg_session != curp->p_session) {
460 PGRP_UNLOCK(pgrp);
461 error = EPERM;
462 goto done;
463 }
464 PGRP_UNLOCK(pgrp);
465 error = enterthispgrp(targp, pgrp);
466 }
467 done:
468 sx_xunlock(&proctree_lock);
469 KASSERT((error == 0) || (newpgrp != NULL),
470 ("setpgid failed and newpgrp is NULL"));
471 if (newpgrp != NULL)
472 free(newpgrp, M_PGRP);
473 return (error);
474 }
475
476 /*
477 * Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD
478 * compatible. It says that setting the uid/gid to euid/egid is a special
479 * case of "appropriate privilege". Once the rules are expanded out, this
480 * basically means that setuid(nnn) sets all three id's, in all permitted
481 * cases unless _POSIX_SAVED_IDS is enabled. In that case, setuid(getuid())
482 * does not set the saved id - this is dangerous for traditional BSD
483 * programs. For this reason, we *really* do not want to set
484 * _POSIX_SAVED_IDS and do not want to clear POSIX_APPENDIX_B_4_2_2.
485 */
486 #define POSIX_APPENDIX_B_4_2_2
487
488 #ifndef _SYS_SYSPROTO_H_
489 struct setuid_args {
490 uid_t uid;
491 };
492 #endif
493 /* ARGSUSED */
494 int
495 sys_setuid(struct thread *td, struct setuid_args *uap)
496 {
497 struct proc *p = td->td_proc;
498 struct ucred *newcred, *oldcred;
499 uid_t uid;
500 struct uidinfo *uip;
501 int error;
502
503 uid = uap->uid;
504 AUDIT_ARG_UID(uid);
505 newcred = crget();
506 uip = uifind(uid);
507 PROC_LOCK(p);
508 /*
509 * Copy credentials so other references do not see our changes.
510 */
511 oldcred = crcopysafe(p, newcred);
512
513 #ifdef MAC
514 error = mac_cred_check_setuid(oldcred, uid);
515 if (error)
516 goto fail;
517 #endif
518
519 /*
520 * See if we have "permission" by POSIX 1003.1 rules.
521 *
522 * Note that setuid(geteuid()) is a special case of
523 * "appropriate privileges" in appendix B.4.2.2. We need
524 * to use this clause to be compatible with traditional BSD
525 * semantics. Basically, it means that "setuid(xx)" sets all
526 * three id's (assuming you have privs).
527 *
528 * Notes on the logic. We do things in three steps.
529 * 1: We determine if the euid is going to change, and do EPERM
530 * right away. We unconditionally change the euid later if this
531 * test is satisfied, simplifying that part of the logic.
532 * 2: We determine if the real and/or saved uids are going to
533 * change. Determined by compile options.
534 * 3: Change euid last. (after tests in #2 for "appropriate privs")
535 */
536 if (uid != oldcred->cr_ruid && /* allow setuid(getuid()) */
537 #ifdef _POSIX_SAVED_IDS
538 uid != oldcred->cr_svuid && /* allow setuid(saved gid) */
539 #endif
540 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
541 uid != oldcred->cr_uid && /* allow setuid(geteuid()) */
542 #endif
543 (error = priv_check_cred(oldcred, PRIV_CRED_SETUID, 0)) != 0)
544 goto fail;
545
546 #ifdef _POSIX_SAVED_IDS
547 /*
548 * Do we have "appropriate privileges" (are we root or uid == euid)
549 * If so, we are changing the real uid and/or saved uid.
550 */
551 if (
552 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use the clause from B.4.2.2 */
553 uid == oldcred->cr_uid ||
554 #endif
555 /* We are using privs. */
556 priv_check_cred(oldcred, PRIV_CRED_SETUID, 0) == 0)
557 #endif
558 {
559 /*
560 * Set the real uid and transfer proc count to new user.
561 */
562 if (uid != oldcred->cr_ruid) {
563 change_ruid(newcred, uip);
564 setsugid(p);
565 }
566 /*
567 * Set saved uid
568 *
569 * XXX always set saved uid even if not _POSIX_SAVED_IDS, as
570 * the security of seteuid() depends on it. B.4.2.2 says it
571 * is important that we should do this.
572 */
573 if (uid != oldcred->cr_svuid) {
574 change_svuid(newcred, uid);
575 setsugid(p);
576 }
577 }
578
579 /*
580 * In all permitted cases, we are changing the euid.
581 */
582 if (uid != oldcred->cr_uid) {
583 change_euid(newcred, uip);
584 setsugid(p);
585 }
586 p->p_ucred = newcred;
587 PROC_UNLOCK(p);
588 #ifdef RACCT
589 racct_proc_ucred_changed(p, oldcred, newcred);
590 #endif
591 uifree(uip);
592 crfree(oldcred);
593 return (0);
594
595 fail:
596 PROC_UNLOCK(p);
597 uifree(uip);
598 crfree(newcred);
599 return (error);
600 }
601
602 #ifndef _SYS_SYSPROTO_H_
603 struct seteuid_args {
604 uid_t euid;
605 };
606 #endif
607 /* ARGSUSED */
608 int
609 sys_seteuid(struct thread *td, struct seteuid_args *uap)
610 {
611 struct proc *p = td->td_proc;
612 struct ucred *newcred, *oldcred;
613 uid_t euid;
614 struct uidinfo *euip;
615 int error;
616
617 euid = uap->euid;
618 AUDIT_ARG_EUID(euid);
619 newcred = crget();
620 euip = uifind(euid);
621 PROC_LOCK(p);
622 /*
623 * Copy credentials so other references do not see our changes.
624 */
625 oldcred = crcopysafe(p, newcred);
626
627 #ifdef MAC
628 error = mac_cred_check_seteuid(oldcred, euid);
629 if (error)
630 goto fail;
631 #endif
632
633 if (euid != oldcred->cr_ruid && /* allow seteuid(getuid()) */
634 euid != oldcred->cr_svuid && /* allow seteuid(saved uid) */
635 (error = priv_check_cred(oldcred, PRIV_CRED_SETEUID, 0)) != 0)
636 goto fail;
637
638 /*
639 * Everything's okay, do it.
640 */
641 if (oldcred->cr_uid != euid) {
642 change_euid(newcred, euip);
643 setsugid(p);
644 }
645 p->p_ucred = newcred;
646 PROC_UNLOCK(p);
647 uifree(euip);
648 crfree(oldcred);
649 return (0);
650
651 fail:
652 PROC_UNLOCK(p);
653 uifree(euip);
654 crfree(newcred);
655 return (error);
656 }
657
658 #ifndef _SYS_SYSPROTO_H_
659 struct setgid_args {
660 gid_t gid;
661 };
662 #endif
663 /* ARGSUSED */
664 int
665 sys_setgid(struct thread *td, struct setgid_args *uap)
666 {
667 struct proc *p = td->td_proc;
668 struct ucred *newcred, *oldcred;
669 gid_t gid;
670 int error;
671
672 gid = uap->gid;
673 AUDIT_ARG_GID(gid);
674 newcred = crget();
675 PROC_LOCK(p);
676 oldcred = crcopysafe(p, newcred);
677
678 #ifdef MAC
679 error = mac_cred_check_setgid(oldcred, gid);
680 if (error)
681 goto fail;
682 #endif
683
684 /*
685 * See if we have "permission" by POSIX 1003.1 rules.
686 *
687 * Note that setgid(getegid()) is a special case of
688 * "appropriate privileges" in appendix B.4.2.2. We need
689 * to use this clause to be compatible with traditional BSD
690 * semantics. Basically, it means that "setgid(xx)" sets all
691 * three id's (assuming you have privs).
692 *
693 * For notes on the logic here, see setuid() above.
694 */
695 if (gid != oldcred->cr_rgid && /* allow setgid(getgid()) */
696 #ifdef _POSIX_SAVED_IDS
697 gid != oldcred->cr_svgid && /* allow setgid(saved gid) */
698 #endif
699 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
700 gid != oldcred->cr_groups[0] && /* allow setgid(getegid()) */
701 #endif
702 (error = priv_check_cred(oldcred, PRIV_CRED_SETGID, 0)) != 0)
703 goto fail;
704
705 #ifdef _POSIX_SAVED_IDS
706 /*
707 * Do we have "appropriate privileges" (are we root or gid == egid)
708 * If so, we are changing the real uid and saved gid.
709 */
710 if (
711 #ifdef POSIX_APPENDIX_B_4_2_2 /* use the clause from B.4.2.2 */
712 gid == oldcred->cr_groups[0] ||
713 #endif
714 /* We are using privs. */
715 priv_check_cred(oldcred, PRIV_CRED_SETGID, 0) == 0)
716 #endif
717 {
718 /*
719 * Set real gid
720 */
721 if (oldcred->cr_rgid != gid) {
722 change_rgid(newcred, gid);
723 setsugid(p);
724 }
725 /*
726 * Set saved gid
727 *
728 * XXX always set saved gid even if not _POSIX_SAVED_IDS, as
729 * the security of setegid() depends on it. B.4.2.2 says it
730 * is important that we should do this.
731 */
732 if (oldcred->cr_svgid != gid) {
733 change_svgid(newcred, gid);
734 setsugid(p);
735 }
736 }
737 /*
738 * In all cases permitted cases, we are changing the egid.
739 * Copy credentials so other references do not see our changes.
740 */
741 if (oldcred->cr_groups[0] != gid) {
742 change_egid(newcred, gid);
743 setsugid(p);
744 }
745 p->p_ucred = newcred;
746 PROC_UNLOCK(p);
747 crfree(oldcred);
748 return (0);
749
750 fail:
751 PROC_UNLOCK(p);
752 crfree(newcred);
753 return (error);
754 }
755
756 #ifndef _SYS_SYSPROTO_H_
757 struct setegid_args {
758 gid_t egid;
759 };
760 #endif
761 /* ARGSUSED */
762 int
763 sys_setegid(struct thread *td, struct setegid_args *uap)
764 {
765 struct proc *p = td->td_proc;
766 struct ucred *newcred, *oldcred;
767 gid_t egid;
768 int error;
769
770 egid = uap->egid;
771 AUDIT_ARG_EGID(egid);
772 newcred = crget();
773 PROC_LOCK(p);
774 oldcred = crcopysafe(p, newcred);
775
776 #ifdef MAC
777 error = mac_cred_check_setegid(oldcred, egid);
778 if (error)
779 goto fail;
780 #endif
781
782 if (egid != oldcred->cr_rgid && /* allow setegid(getgid()) */
783 egid != oldcred->cr_svgid && /* allow setegid(saved gid) */
784 (error = priv_check_cred(oldcred, PRIV_CRED_SETEGID, 0)) != 0)
785 goto fail;
786
787 if (oldcred->cr_groups[0] != egid) {
788 change_egid(newcred, egid);
789 setsugid(p);
790 }
791 p->p_ucred = newcred;
792 PROC_UNLOCK(p);
793 crfree(oldcred);
794 return (0);
795
796 fail:
797 PROC_UNLOCK(p);
798 crfree(newcred);
799 return (error);
800 }
801
802 #ifndef _SYS_SYSPROTO_H_
803 struct setgroups_args {
804 u_int gidsetsize;
805 gid_t *gidset;
806 };
807 #endif
808 /* ARGSUSED */
809 int
810 sys_setgroups(struct thread *td, struct setgroups_args *uap)
811 {
812 gid_t *groups = NULL;
813 int error;
814
815 if (uap->gidsetsize > ngroups_max + 1)
816 return (EINVAL);
817 groups = malloc(uap->gidsetsize * sizeof(gid_t), M_TEMP, M_WAITOK);
818 error = copyin(uap->gidset, groups, uap->gidsetsize * sizeof(gid_t));
819 if (error)
820 goto out;
821 error = kern_setgroups(td, uap->gidsetsize, groups);
822 out:
823 free(groups, M_TEMP);
824 return (error);
825 }
826
827 int
828 kern_setgroups(struct thread *td, u_int ngrp, gid_t *groups)
829 {
830 struct proc *p = td->td_proc;
831 struct ucred *newcred, *oldcred;
832 int error;
833
834 if (ngrp > ngroups_max + 1)
835 return (EINVAL);
836 AUDIT_ARG_GROUPSET(groups, ngrp);
837 newcred = crget();
838 crextend(newcred, ngrp);
839 PROC_LOCK(p);
840 oldcred = crcopysafe(p, newcred);
841
842 #ifdef MAC
843 error = mac_cred_check_setgroups(oldcred, ngrp, groups);
844 if (error)
845 goto fail;
846 #endif
847
848 error = priv_check_cred(oldcred, PRIV_CRED_SETGROUPS, 0);
849 if (error)
850 goto fail;
851
852 if (ngrp < 1) {
853 /*
854 * setgroups(0, NULL) is a legitimate way of clearing the
855 * groups vector on non-BSD systems (which generally do not
856 * have the egid in the groups[0]). We risk security holes
857 * when running non-BSD software if we do not do the same.
858 */
859 newcred->cr_ngroups = 1;
860 } else {
861 crsetgroups_locked(newcred, ngrp, groups);
862 }
863 setsugid(p);
864 p->p_ucred = newcred;
865 PROC_UNLOCK(p);
866 crfree(oldcred);
867 return (0);
868
869 fail:
870 PROC_UNLOCK(p);
871 crfree(newcred);
872 return (error);
873 }
874
875 #ifndef _SYS_SYSPROTO_H_
876 struct setreuid_args {
877 uid_t ruid;
878 uid_t euid;
879 };
880 #endif
881 /* ARGSUSED */
882 int
883 sys_setreuid(register struct thread *td, struct setreuid_args *uap)
884 {
885 struct proc *p = td->td_proc;
886 struct ucred *newcred, *oldcred;
887 uid_t euid, ruid;
888 struct uidinfo *euip, *ruip;
889 int error;
890
891 euid = uap->euid;
892 ruid = uap->ruid;
893 AUDIT_ARG_EUID(euid);
894 AUDIT_ARG_RUID(ruid);
895 newcred = crget();
896 euip = uifind(euid);
897 ruip = uifind(ruid);
898 PROC_LOCK(p);
899 oldcred = crcopysafe(p, newcred);
900
901 #ifdef MAC
902 error = mac_cred_check_setreuid(oldcred, ruid, euid);
903 if (error)
904 goto fail;
905 #endif
906
907 if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
908 ruid != oldcred->cr_svuid) ||
909 (euid != (uid_t)-1 && euid != oldcred->cr_uid &&
910 euid != oldcred->cr_ruid && euid != oldcred->cr_svuid)) &&
911 (error = priv_check_cred(oldcred, PRIV_CRED_SETREUID, 0)) != 0)
912 goto fail;
913
914 if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
915 change_euid(newcred, euip);
916 setsugid(p);
917 }
918 if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
919 change_ruid(newcred, ruip);
920 setsugid(p);
921 }
922 if ((ruid != (uid_t)-1 || newcred->cr_uid != newcred->cr_ruid) &&
923 newcred->cr_svuid != newcred->cr_uid) {
924 change_svuid(newcred, newcred->cr_uid);
925 setsugid(p);
926 }
927 p->p_ucred = newcred;
928 PROC_UNLOCK(p);
929 #ifdef RACCT
930 racct_proc_ucred_changed(p, oldcred, newcred);
931 #endif
932 uifree(ruip);
933 uifree(euip);
934 crfree(oldcred);
935 return (0);
936
937 fail:
938 PROC_UNLOCK(p);
939 uifree(ruip);
940 uifree(euip);
941 crfree(newcred);
942 return (error);
943 }
944
945 #ifndef _SYS_SYSPROTO_H_
946 struct setregid_args {
947 gid_t rgid;
948 gid_t egid;
949 };
950 #endif
951 /* ARGSUSED */
952 int
953 sys_setregid(register struct thread *td, struct setregid_args *uap)
954 {
955 struct proc *p = td->td_proc;
956 struct ucred *newcred, *oldcred;
957 gid_t egid, rgid;
958 int error;
959
960 egid = uap->egid;
961 rgid = uap->rgid;
962 AUDIT_ARG_EGID(egid);
963 AUDIT_ARG_RGID(rgid);
964 newcred = crget();
965 PROC_LOCK(p);
966 oldcred = crcopysafe(p, newcred);
967
968 #ifdef MAC
969 error = mac_cred_check_setregid(oldcred, rgid, egid);
970 if (error)
971 goto fail;
972 #endif
973
974 if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
975 rgid != oldcred->cr_svgid) ||
976 (egid != (gid_t)-1 && egid != oldcred->cr_groups[0] &&
977 egid != oldcred->cr_rgid && egid != oldcred->cr_svgid)) &&
978 (error = priv_check_cred(oldcred, PRIV_CRED_SETREGID, 0)) != 0)
979 goto fail;
980
981 if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
982 change_egid(newcred, egid);
983 setsugid(p);
984 }
985 if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
986 change_rgid(newcred, rgid);
987 setsugid(p);
988 }
989 if ((rgid != (gid_t)-1 || newcred->cr_groups[0] != newcred->cr_rgid) &&
990 newcred->cr_svgid != newcred->cr_groups[0]) {
991 change_svgid(newcred, newcred->cr_groups[0]);
992 setsugid(p);
993 }
994 p->p_ucred = newcred;
995 PROC_UNLOCK(p);
996 crfree(oldcred);
997 return (0);
998
999 fail:
1000 PROC_UNLOCK(p);
1001 crfree(newcred);
1002 return (error);
1003 }
1004
1005 /*
1006 * setresuid(ruid, euid, suid) is like setreuid except control over the saved
1007 * uid is explicit.
1008 */
1009 #ifndef _SYS_SYSPROTO_H_
1010 struct setresuid_args {
1011 uid_t ruid;
1012 uid_t euid;
1013 uid_t suid;
1014 };
1015 #endif
1016 /* ARGSUSED */
1017 int
1018 sys_setresuid(register struct thread *td, struct setresuid_args *uap)
1019 {
1020 struct proc *p = td->td_proc;
1021 struct ucred *newcred, *oldcred;
1022 uid_t euid, ruid, suid;
1023 struct uidinfo *euip, *ruip;
1024 int error;
1025
1026 euid = uap->euid;
1027 ruid = uap->ruid;
1028 suid = uap->suid;
1029 AUDIT_ARG_EUID(euid);
1030 AUDIT_ARG_RUID(ruid);
1031 AUDIT_ARG_SUID(suid);
1032 newcred = crget();
1033 euip = uifind(euid);
1034 ruip = uifind(ruid);
1035 PROC_LOCK(p);
1036 oldcred = crcopysafe(p, newcred);
1037
1038 #ifdef MAC
1039 error = mac_cred_check_setresuid(oldcred, ruid, euid, suid);
1040 if (error)
1041 goto fail;
1042 #endif
1043
1044 if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
1045 ruid != oldcred->cr_svuid &&
1046 ruid != oldcred->cr_uid) ||
1047 (euid != (uid_t)-1 && euid != oldcred->cr_ruid &&
1048 euid != oldcred->cr_svuid &&
1049 euid != oldcred->cr_uid) ||
1050 (suid != (uid_t)-1 && suid != oldcred->cr_ruid &&
1051 suid != oldcred->cr_svuid &&
1052 suid != oldcred->cr_uid)) &&
1053 (error = priv_check_cred(oldcred, PRIV_CRED_SETRESUID, 0)) != 0)
1054 goto fail;
1055
1056 if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
1057 change_euid(newcred, euip);
1058 setsugid(p);
1059 }
1060 if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
1061 change_ruid(newcred, ruip);
1062 setsugid(p);
1063 }
1064 if (suid != (uid_t)-1 && oldcred->cr_svuid != suid) {
1065 change_svuid(newcred, suid);
1066 setsugid(p);
1067 }
1068 p->p_ucred = newcred;
1069 PROC_UNLOCK(p);
1070 #ifdef RACCT
1071 racct_proc_ucred_changed(p, oldcred, newcred);
1072 #endif
1073 uifree(ruip);
1074 uifree(euip);
1075 crfree(oldcred);
1076 return (0);
1077
1078 fail:
1079 PROC_UNLOCK(p);
1080 uifree(ruip);
1081 uifree(euip);
1082 crfree(newcred);
1083 return (error);
1084
1085 }
1086
1087 /*
1088 * setresgid(rgid, egid, sgid) is like setregid except control over the saved
1089 * gid is explicit.
1090 */
1091 #ifndef _SYS_SYSPROTO_H_
1092 struct setresgid_args {
1093 gid_t rgid;
1094 gid_t egid;
1095 gid_t sgid;
1096 };
1097 #endif
1098 /* ARGSUSED */
1099 int
1100 sys_setresgid(register struct thread *td, struct setresgid_args *uap)
1101 {
1102 struct proc *p = td->td_proc;
1103 struct ucred *newcred, *oldcred;
1104 gid_t egid, rgid, sgid;
1105 int error;
1106
1107 egid = uap->egid;
1108 rgid = uap->rgid;
1109 sgid = uap->sgid;
1110 AUDIT_ARG_EGID(egid);
1111 AUDIT_ARG_RGID(rgid);
1112 AUDIT_ARG_SGID(sgid);
1113 newcred = crget();
1114 PROC_LOCK(p);
1115 oldcred = crcopysafe(p, newcred);
1116
1117 #ifdef MAC
1118 error = mac_cred_check_setresgid(oldcred, rgid, egid, sgid);
1119 if (error)
1120 goto fail;
1121 #endif
1122
1123 if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
1124 rgid != oldcred->cr_svgid &&
1125 rgid != oldcred->cr_groups[0]) ||
1126 (egid != (gid_t)-1 && egid != oldcred->cr_rgid &&
1127 egid != oldcred->cr_svgid &&
1128 egid != oldcred->cr_groups[0]) ||
1129 (sgid != (gid_t)-1 && sgid != oldcred->cr_rgid &&
1130 sgid != oldcred->cr_svgid &&
1131 sgid != oldcred->cr_groups[0])) &&
1132 (error = priv_check_cred(oldcred, PRIV_CRED_SETRESGID, 0)) != 0)
1133 goto fail;
1134
1135 if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
1136 change_egid(newcred, egid);
1137 setsugid(p);
1138 }
1139 if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
1140 change_rgid(newcred, rgid);
1141 setsugid(p);
1142 }
1143 if (sgid != (gid_t)-1 && oldcred->cr_svgid != sgid) {
1144 change_svgid(newcred, sgid);
1145 setsugid(p);
1146 }
1147 p->p_ucred = newcred;
1148 PROC_UNLOCK(p);
1149 crfree(oldcred);
1150 return (0);
1151
1152 fail:
1153 PROC_UNLOCK(p);
1154 crfree(newcred);
1155 return (error);
1156 }
1157
1158 #ifndef _SYS_SYSPROTO_H_
1159 struct getresuid_args {
1160 uid_t *ruid;
1161 uid_t *euid;
1162 uid_t *suid;
1163 };
1164 #endif
1165 /* ARGSUSED */
1166 int
1167 sys_getresuid(register struct thread *td, struct getresuid_args *uap)
1168 {
1169 struct ucred *cred;
1170 int error1 = 0, error2 = 0, error3 = 0;
1171
1172 cred = td->td_ucred;
1173 if (uap->ruid)
1174 error1 = copyout(&cred->cr_ruid,
1175 uap->ruid, sizeof(cred->cr_ruid));
1176 if (uap->euid)
1177 error2 = copyout(&cred->cr_uid,
1178 uap->euid, sizeof(cred->cr_uid));
1179 if (uap->suid)
1180 error3 = copyout(&cred->cr_svuid,
1181 uap->suid, sizeof(cred->cr_svuid));
1182 return (error1 ? error1 : error2 ? error2 : error3);
1183 }
1184
1185 #ifndef _SYS_SYSPROTO_H_
1186 struct getresgid_args {
1187 gid_t *rgid;
1188 gid_t *egid;
1189 gid_t *sgid;
1190 };
1191 #endif
1192 /* ARGSUSED */
1193 int
1194 sys_getresgid(register struct thread *td, struct getresgid_args *uap)
1195 {
1196 struct ucred *cred;
1197 int error1 = 0, error2 = 0, error3 = 0;
1198
1199 cred = td->td_ucred;
1200 if (uap->rgid)
1201 error1 = copyout(&cred->cr_rgid,
1202 uap->rgid, sizeof(cred->cr_rgid));
1203 if (uap->egid)
1204 error2 = copyout(&cred->cr_groups[0],
1205 uap->egid, sizeof(cred->cr_groups[0]));
1206 if (uap->sgid)
1207 error3 = copyout(&cred->cr_svgid,
1208 uap->sgid, sizeof(cred->cr_svgid));
1209 return (error1 ? error1 : error2 ? error2 : error3);
1210 }
1211
1212 #ifndef _SYS_SYSPROTO_H_
1213 struct issetugid_args {
1214 int dummy;
1215 };
1216 #endif
1217 /* ARGSUSED */
1218 int
1219 sys_issetugid(register struct thread *td, struct issetugid_args *uap)
1220 {
1221 struct proc *p = td->td_proc;
1222
1223 /*
1224 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
1225 * we use P_SUGID because we consider changing the owners as
1226 * "tainting" as well.
1227 * This is significant for procs that start as root and "become"
1228 * a user without an exec - programs cannot know *everything*
1229 * that libc *might* have put in their data segment.
1230 */
1231 PROC_LOCK(p);
1232 td->td_retval[0] = (p->p_flag & P_SUGID) ? 1 : 0;
1233 PROC_UNLOCK(p);
1234 return (0);
1235 }
1236
1237 int
1238 sys___setugid(struct thread *td, struct __setugid_args *uap)
1239 {
1240 #ifdef REGRESSION
1241 struct proc *p;
1242
1243 p = td->td_proc;
1244 switch (uap->flag) {
1245 case 0:
1246 PROC_LOCK(p);
1247 p->p_flag &= ~P_SUGID;
1248 PROC_UNLOCK(p);
1249 return (0);
1250 case 1:
1251 PROC_LOCK(p);
1252 p->p_flag |= P_SUGID;
1253 PROC_UNLOCK(p);
1254 return (0);
1255 default:
1256 return (EINVAL);
1257 }
1258 #else /* !REGRESSION */
1259
1260 return (ENOSYS);
1261 #endif /* REGRESSION */
1262 }
1263
1264 /*
1265 * Check if gid is a member of the group set.
1266 */
1267 int
1268 groupmember(gid_t gid, struct ucred *cred)
1269 {
1270 int l;
1271 int h;
1272 int m;
1273
1274 if (cred->cr_groups[0] == gid)
1275 return(1);
1276
1277 /*
1278 * If gid was not our primary group, perform a binary search
1279 * of the supplemental groups. This is possible because we
1280 * sort the groups in crsetgroups().
1281 */
1282 l = 1;
1283 h = cred->cr_ngroups;
1284 while (l < h) {
1285 m = l + ((h - l) / 2);
1286 if (cred->cr_groups[m] < gid)
1287 l = m + 1;
1288 else
1289 h = m;
1290 }
1291 if ((l < cred->cr_ngroups) && (cred->cr_groups[l] == gid))
1292 return (1);
1293
1294 return (0);
1295 }
1296
1297 /*
1298 * Test the active securelevel against a given level. securelevel_gt()
1299 * implements (securelevel > level). securelevel_ge() implements
1300 * (securelevel >= level). Note that the logic is inverted -- these
1301 * functions return EPERM on "success" and 0 on "failure".
1302 *
1303 * Due to care taken when setting the securelevel, we know that no jail will
1304 * be less secure that its parent (or the physical system), so it is sufficient
1305 * to test the current jail only.
1306 *
1307 * XXXRW: Possibly since this has to do with privilege, it should move to
1308 * kern_priv.c.
1309 */
1310 int
1311 securelevel_gt(struct ucred *cr, int level)
1312 {
1313
1314 return (cr->cr_prison->pr_securelevel > level ? EPERM : 0);
1315 }
1316
1317 int
1318 securelevel_ge(struct ucred *cr, int level)
1319 {
1320
1321 return (cr->cr_prison->pr_securelevel >= level ? EPERM : 0);
1322 }
1323
1324 /*
1325 * 'see_other_uids' determines whether or not visibility of processes
1326 * and sockets with credentials holding different real uids is possible
1327 * using a variety of system MIBs.
1328 * XXX: data declarations should be together near the beginning of the file.
1329 */
1330 static int see_other_uids = 1;
1331 SYSCTL_INT(_security_bsd, OID_AUTO, see_other_uids, CTLFLAG_RW,
1332 &see_other_uids, 0,
1333 "Unprivileged processes may see subjects/objects with different real uid");
1334
1335 /*-
1336 * Determine if u1 "can see" the subject specified by u2, according to the
1337 * 'see_other_uids' policy.
1338 * Returns: 0 for permitted, ESRCH otherwise
1339 * Locks: none
1340 * References: *u1 and *u2 must not change during the call
1341 * u1 may equal u2, in which case only one reference is required
1342 */
1343 static int
1344 cr_seeotheruids(struct ucred *u1, struct ucred *u2)
1345 {
1346
1347 if (!see_other_uids && u1->cr_ruid != u2->cr_ruid) {
1348 if (priv_check_cred(u1, PRIV_SEEOTHERUIDS, 0) != 0)
1349 return (ESRCH);
1350 }
1351 return (0);
1352 }
1353
1354 /*
1355 * 'see_other_gids' determines whether or not visibility of processes
1356 * and sockets with credentials holding different real gids is possible
1357 * using a variety of system MIBs.
1358 * XXX: data declarations should be together near the beginning of the file.
1359 */
1360 static int see_other_gids = 1;
1361 SYSCTL_INT(_security_bsd, OID_AUTO, see_other_gids, CTLFLAG_RW,
1362 &see_other_gids, 0,
1363 "Unprivileged processes may see subjects/objects with different real gid");
1364
1365 /*
1366 * Determine if u1 can "see" the subject specified by u2, according to the
1367 * 'see_other_gids' policy.
1368 * Returns: 0 for permitted, ESRCH otherwise
1369 * Locks: none
1370 * References: *u1 and *u2 must not change during the call
1371 * u1 may equal u2, in which case only one reference is required
1372 */
1373 static int
1374 cr_seeothergids(struct ucred *u1, struct ucred *u2)
1375 {
1376 int i, match;
1377
1378 if (!see_other_gids) {
1379 match = 0;
1380 for (i = 0; i < u1->cr_ngroups; i++) {
1381 if (groupmember(u1->cr_groups[i], u2))
1382 match = 1;
1383 if (match)
1384 break;
1385 }
1386 if (!match) {
1387 if (priv_check_cred(u1, PRIV_SEEOTHERGIDS, 0) != 0)
1388 return (ESRCH);
1389 }
1390 }
1391 return (0);
1392 }
1393
1394 /*-
1395 * Determine if u1 "can see" the subject specified by u2.
1396 * Returns: 0 for permitted, an errno value otherwise
1397 * Locks: none
1398 * References: *u1 and *u2 must not change during the call
1399 * u1 may equal u2, in which case only one reference is required
1400 */
1401 int
1402 cr_cansee(struct ucred *u1, struct ucred *u2)
1403 {
1404 int error;
1405
1406 if ((error = prison_check(u1, u2)))
1407 return (error);
1408 #ifdef MAC
1409 if ((error = mac_cred_check_visible(u1, u2)))
1410 return (error);
1411 #endif
1412 if ((error = cr_seeotheruids(u1, u2)))
1413 return (error);
1414 if ((error = cr_seeothergids(u1, u2)))
1415 return (error);
1416 return (0);
1417 }
1418
1419 /*-
1420 * Determine if td "can see" the subject specified by p.
1421 * Returns: 0 for permitted, an errno value otherwise
1422 * Locks: Sufficient locks to protect p->p_ucred must be held. td really
1423 * should be curthread.
1424 * References: td and p must be valid for the lifetime of the call
1425 */
1426 int
1427 p_cansee(struct thread *td, struct proc *p)
1428 {
1429
1430 /* Wrap cr_cansee() for all functionality. */
1431 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1432 PROC_LOCK_ASSERT(p, MA_OWNED);
1433 return (cr_cansee(td->td_ucred, p->p_ucred));
1434 }
1435
1436 /*
1437 * 'conservative_signals' prevents the delivery of a broad class of
1438 * signals by unprivileged processes to processes that have changed their
1439 * credentials since the last invocation of execve(). This can prevent
1440 * the leakage of cached information or retained privileges as a result
1441 * of a common class of signal-related vulnerabilities. However, this
1442 * may interfere with some applications that expect to be able to
1443 * deliver these signals to peer processes after having given up
1444 * privilege.
1445 */
1446 static int conservative_signals = 1;
1447 SYSCTL_INT(_security_bsd, OID_AUTO, conservative_signals, CTLFLAG_RW,
1448 &conservative_signals, 0, "Unprivileged processes prevented from "
1449 "sending certain signals to processes whose credentials have changed");
1450 /*-
1451 * Determine whether cred may deliver the specified signal to proc.
1452 * Returns: 0 for permitted, an errno value otherwise.
1453 * Locks: A lock must be held for proc.
1454 * References: cred and proc must be valid for the lifetime of the call.
1455 */
1456 int
1457 cr_cansignal(struct ucred *cred, struct proc *proc, int signum)
1458 {
1459 int error;
1460
1461 PROC_LOCK_ASSERT(proc, MA_OWNED);
1462 /*
1463 * Jail semantics limit the scope of signalling to proc in the
1464 * same jail as cred, if cred is in jail.
1465 */
1466 error = prison_check(cred, proc->p_ucred);
1467 if (error)
1468 return (error);
1469 #ifdef MAC
1470 if ((error = mac_proc_check_signal(cred, proc, signum)))
1471 return (error);
1472 #endif
1473 if ((error = cr_seeotheruids(cred, proc->p_ucred)))
1474 return (error);
1475 if ((error = cr_seeothergids(cred, proc->p_ucred)))
1476 return (error);
1477
1478 /*
1479 * UNIX signal semantics depend on the status of the P_SUGID
1480 * bit on the target process. If the bit is set, then additional
1481 * restrictions are placed on the set of available signals.
1482 */
1483 if (conservative_signals && (proc->p_flag & P_SUGID)) {
1484 switch (signum) {
1485 case 0:
1486 case SIGKILL:
1487 case SIGINT:
1488 case SIGTERM:
1489 case SIGALRM:
1490 case SIGSTOP:
1491 case SIGTTIN:
1492 case SIGTTOU:
1493 case SIGTSTP:
1494 case SIGHUP:
1495 case SIGUSR1:
1496 case SIGUSR2:
1497 /*
1498 * Generally, permit job and terminal control
1499 * signals.
1500 */
1501 break;
1502 default:
1503 /* Not permitted without privilege. */
1504 error = priv_check_cred(cred, PRIV_SIGNAL_SUGID, 0);
1505 if (error)
1506 return (error);
1507 }
1508 }
1509
1510 /*
1511 * Generally, the target credential's ruid or svuid must match the
1512 * subject credential's ruid or euid.
1513 */
1514 if (cred->cr_ruid != proc->p_ucred->cr_ruid &&
1515 cred->cr_ruid != proc->p_ucred->cr_svuid &&
1516 cred->cr_uid != proc->p_ucred->cr_ruid &&
1517 cred->cr_uid != proc->p_ucred->cr_svuid) {
1518 error = priv_check_cred(cred, PRIV_SIGNAL_DIFFCRED, 0);
1519 if (error)
1520 return (error);
1521 }
1522
1523 return (0);
1524 }
1525
1526 /*-
1527 * Determine whether td may deliver the specified signal to p.
1528 * Returns: 0 for permitted, an errno value otherwise
1529 * Locks: Sufficient locks to protect various components of td and p
1530 * must be held. td must be curthread, and a lock must be
1531 * held for p.
1532 * References: td and p must be valid for the lifetime of the call
1533 */
1534 int
1535 p_cansignal(struct thread *td, struct proc *p, int signum)
1536 {
1537
1538 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1539 PROC_LOCK_ASSERT(p, MA_OWNED);
1540 if (td->td_proc == p)
1541 return (0);
1542
1543 /*
1544 * UNIX signalling semantics require that processes in the same
1545 * session always be able to deliver SIGCONT to one another,
1546 * overriding the remaining protections.
1547 */
1548 /* XXX: This will require an additional lock of some sort. */
1549 if (signum == SIGCONT && td->td_proc->p_session == p->p_session)
1550 return (0);
1551 /*
1552 * Some compat layers use SIGTHR and higher signals for
1553 * communication between different kernel threads of the same
1554 * process, so that they expect that it's always possible to
1555 * deliver them, even for suid applications where cr_cansignal() can
1556 * deny such ability for security consideration. It should be
1557 * pretty safe to do since the only way to create two processes
1558 * with the same p_leader is via rfork(2).
1559 */
1560 if (td->td_proc->p_leader != NULL && signum >= SIGTHR &&
1561 signum < SIGTHR + 4 && td->td_proc->p_leader == p->p_leader)
1562 return (0);
1563
1564 return (cr_cansignal(td->td_ucred, p, signum));
1565 }
1566
1567 /*-
1568 * Determine whether td may reschedule p.
1569 * Returns: 0 for permitted, an errno value otherwise
1570 * Locks: Sufficient locks to protect various components of td and p
1571 * must be held. td must be curthread, and a lock must
1572 * be held for p.
1573 * References: td and p must be valid for the lifetime of the call
1574 */
1575 int
1576 p_cansched(struct thread *td, struct proc *p)
1577 {
1578 int error;
1579
1580 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1581 PROC_LOCK_ASSERT(p, MA_OWNED);
1582 if (td->td_proc == p)
1583 return (0);
1584 if ((error = prison_check(td->td_ucred, p->p_ucred)))
1585 return (error);
1586 #ifdef MAC
1587 if ((error = mac_proc_check_sched(td->td_ucred, p)))
1588 return (error);
1589 #endif
1590 if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
1591 return (error);
1592 if ((error = cr_seeothergids(td->td_ucred, p->p_ucred)))
1593 return (error);
1594 if (td->td_ucred->cr_ruid != p->p_ucred->cr_ruid &&
1595 td->td_ucred->cr_uid != p->p_ucred->cr_ruid) {
1596 error = priv_check(td, PRIV_SCHED_DIFFCRED);
1597 if (error)
1598 return (error);
1599 }
1600 return (0);
1601 }
1602
1603 /*
1604 * The 'unprivileged_proc_debug' flag may be used to disable a variety of
1605 * unprivileged inter-process debugging services, including some procfs
1606 * functionality, ptrace(), and ktrace(). In the past, inter-process
1607 * debugging has been involved in a variety of security problems, and sites
1608 * not requiring the service might choose to disable it when hardening
1609 * systems.
1610 *
1611 * XXX: Should modifying and reading this variable require locking?
1612 * XXX: data declarations should be together near the beginning of the file.
1613 */
1614 static int unprivileged_proc_debug = 1;
1615 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_proc_debug, CTLFLAG_RW,
1616 &unprivileged_proc_debug, 0,
1617 "Unprivileged processes may use process debugging facilities");
1618
1619 /*-
1620 * Determine whether td may debug p.
1621 * Returns: 0 for permitted, an errno value otherwise
1622 * Locks: Sufficient locks to protect various components of td and p
1623 * must be held. td must be curthread, and a lock must
1624 * be held for p.
1625 * References: td and p must be valid for the lifetime of the call
1626 */
1627 int
1628 p_candebug(struct thread *td, struct proc *p)
1629 {
1630 int credentialchanged, error, grpsubset, i, uidsubset;
1631
1632 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1633 PROC_LOCK_ASSERT(p, MA_OWNED);
1634 if (!unprivileged_proc_debug) {
1635 error = priv_check(td, PRIV_DEBUG_UNPRIV);
1636 if (error)
1637 return (error);
1638 }
1639 if (td->td_proc == p)
1640 return (0);
1641 if ((error = prison_check(td->td_ucred, p->p_ucred)))
1642 return (error);
1643 #ifdef MAC
1644 if ((error = mac_proc_check_debug(td->td_ucred, p)))
1645 return (error);
1646 #endif
1647 if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
1648 return (error);
1649 if ((error = cr_seeothergids(td->td_ucred, p->p_ucred)))
1650 return (error);
1651
1652 /*
1653 * Is p's group set a subset of td's effective group set? This
1654 * includes p's egid, group access list, rgid, and svgid.
1655 */
1656 grpsubset = 1;
1657 for (i = 0; i < p->p_ucred->cr_ngroups; i++) {
1658 if (!groupmember(p->p_ucred->cr_groups[i], td->td_ucred)) {
1659 grpsubset = 0;
1660 break;
1661 }
1662 }
1663 grpsubset = grpsubset &&
1664 groupmember(p->p_ucred->cr_rgid, td->td_ucred) &&
1665 groupmember(p->p_ucred->cr_svgid, td->td_ucred);
1666
1667 /*
1668 * Are the uids present in p's credential equal to td's
1669 * effective uid? This includes p's euid, svuid, and ruid.
1670 */
1671 uidsubset = (td->td_ucred->cr_uid == p->p_ucred->cr_uid &&
1672 td->td_ucred->cr_uid == p->p_ucred->cr_svuid &&
1673 td->td_ucred->cr_uid == p->p_ucred->cr_ruid);
1674
1675 /*
1676 * Has the credential of the process changed since the last exec()?
1677 */
1678 credentialchanged = (p->p_flag & P_SUGID);
1679
1680 /*
1681 * If p's gids aren't a subset, or the uids aren't a subset,
1682 * or the credential has changed, require appropriate privilege
1683 * for td to debug p.
1684 */
1685 if (!grpsubset || !uidsubset) {
1686 error = priv_check(td, PRIV_DEBUG_DIFFCRED);
1687 if (error)
1688 return (error);
1689 }
1690
1691 if (credentialchanged) {
1692 error = priv_check(td, PRIV_DEBUG_SUGID);
1693 if (error)
1694 return (error);
1695 }
1696
1697 /* Can't trace init when securelevel > 0. */
1698 if (p == initproc) {
1699 error = securelevel_gt(td->td_ucred, 0);
1700 if (error)
1701 return (error);
1702 }
1703
1704 /*
1705 * Can't trace a process that's currently exec'ing.
1706 *
1707 * XXX: Note, this is not a security policy decision, it's a
1708 * basic correctness/functionality decision. Therefore, this check
1709 * should be moved to the caller's of p_candebug().
1710 */
1711 if ((p->p_flag & P_INEXEC) != 0)
1712 return (EBUSY);
1713
1714 return (0);
1715 }
1716
1717 /*-
1718 * Determine whether the subject represented by cred can "see" a socket.
1719 * Returns: 0 for permitted, ENOENT otherwise.
1720 */
1721 int
1722 cr_canseesocket(struct ucred *cred, struct socket *so)
1723 {
1724 int error;
1725
1726 error = prison_check(cred, so->so_cred);
1727 if (error)
1728 return (ENOENT);
1729 #ifdef MAC
1730 error = mac_socket_check_visible(cred, so);
1731 if (error)
1732 return (error);
1733 #endif
1734 if (cr_seeotheruids(cred, so->so_cred))
1735 return (ENOENT);
1736 if (cr_seeothergids(cred, so->so_cred))
1737 return (ENOENT);
1738
1739 return (0);
1740 }
1741
1742 #if defined(INET) || defined(INET6)
1743 /*-
1744 * Determine whether the subject represented by cred can "see" a socket.
1745 * Returns: 0 for permitted, ENOENT otherwise.
1746 */
1747 int
1748 cr_canseeinpcb(struct ucred *cred, struct inpcb *inp)
1749 {
1750 int error;
1751
1752 error = prison_check(cred, inp->inp_cred);
1753 if (error)
1754 return (ENOENT);
1755 #ifdef MAC
1756 INP_LOCK_ASSERT(inp);
1757 error = mac_inpcb_check_visible(cred, inp);
1758 if (error)
1759 return (error);
1760 #endif
1761 if (cr_seeotheruids(cred, inp->inp_cred))
1762 return (ENOENT);
1763 if (cr_seeothergids(cred, inp->inp_cred))
1764 return (ENOENT);
1765
1766 return (0);
1767 }
1768 #endif
1769
1770 /*-
1771 * Determine whether td can wait for the exit of p.
1772 * Returns: 0 for permitted, an errno value otherwise
1773 * Locks: Sufficient locks to protect various components of td and p
1774 * must be held. td must be curthread, and a lock must
1775 * be held for p.
1776 * References: td and p must be valid for the lifetime of the call
1777
1778 */
1779 int
1780 p_canwait(struct thread *td, struct proc *p)
1781 {
1782 int error;
1783
1784 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1785 PROC_LOCK_ASSERT(p, MA_OWNED);
1786 if ((error = prison_check(td->td_ucred, p->p_ucred)))
1787 return (error);
1788 #ifdef MAC
1789 if ((error = mac_proc_check_wait(td->td_ucred, p)))
1790 return (error);
1791 #endif
1792 #if 0
1793 /* XXXMAC: This could have odd effects on some shells. */
1794 if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
1795 return (error);
1796 #endif
1797
1798 return (0);
1799 }
1800
1801 /*
1802 * Allocate a zeroed cred structure.
1803 */
1804 struct ucred *
1805 crget(void)
1806 {
1807 register struct ucred *cr;
1808
1809 cr = malloc(sizeof(*cr), M_CRED, M_WAITOK | M_ZERO);
1810 refcount_init(&cr->cr_ref, 1);
1811 #ifdef AUDIT
1812 audit_cred_init(cr);
1813 #endif
1814 #ifdef MAC
1815 mac_cred_init(cr);
1816 #endif
1817 crextend(cr, XU_NGROUPS);
1818 return (cr);
1819 }
1820
1821 /*
1822 * Claim another reference to a ucred structure.
1823 */
1824 struct ucred *
1825 crhold(struct ucred *cr)
1826 {
1827
1828 refcount_acquire(&cr->cr_ref);
1829 return (cr);
1830 }
1831
1832 /*
1833 * Free a cred structure. Throws away space when ref count gets to 0.
1834 */
1835 void
1836 crfree(struct ucred *cr)
1837 {
1838
1839 KASSERT(cr->cr_ref > 0, ("bad ucred refcount: %d", cr->cr_ref));
1840 KASSERT(cr->cr_ref != 0xdeadc0de, ("dangling reference to ucred"));
1841 if (refcount_release(&cr->cr_ref)) {
1842 /*
1843 * Some callers of crget(), such as nfs_statfs(),
1844 * allocate a temporary credential, but don't
1845 * allocate a uidinfo structure.
1846 */
1847 if (cr->cr_uidinfo != NULL)
1848 uifree(cr->cr_uidinfo);
1849 if (cr->cr_ruidinfo != NULL)
1850 uifree(cr->cr_ruidinfo);
1851 /*
1852 * Free a prison, if any.
1853 */
1854 if (cr->cr_prison != NULL)
1855 prison_free(cr->cr_prison);
1856 if (cr->cr_loginclass != NULL)
1857 loginclass_free(cr->cr_loginclass);
1858 #ifdef AUDIT
1859 audit_cred_destroy(cr);
1860 #endif
1861 #ifdef MAC
1862 mac_cred_destroy(cr);
1863 #endif
1864 free(cr->cr_groups, M_CRED);
1865 free(cr, M_CRED);
1866 }
1867 }
1868
1869 /*
1870 * Check to see if this ucred is shared.
1871 */
1872 int
1873 crshared(struct ucred *cr)
1874 {
1875
1876 return (cr->cr_ref > 1);
1877 }
1878
1879 /*
1880 * Copy a ucred's contents from a template. Does not block.
1881 */
1882 void
1883 crcopy(struct ucred *dest, struct ucred *src)
1884 {
1885
1886 KASSERT(crshared(dest) == 0, ("crcopy of shared ucred"));
1887 bcopy(&src->cr_startcopy, &dest->cr_startcopy,
1888 (unsigned)((caddr_t)&src->cr_endcopy -
1889 (caddr_t)&src->cr_startcopy));
1890 crsetgroups(dest, src->cr_ngroups, src->cr_groups);
1891 uihold(dest->cr_uidinfo);
1892 uihold(dest->cr_ruidinfo);
1893 prison_hold(dest->cr_prison);
1894 loginclass_hold(dest->cr_loginclass);
1895 #ifdef AUDIT
1896 audit_cred_copy(src, dest);
1897 #endif
1898 #ifdef MAC
1899 mac_cred_copy(src, dest);
1900 #endif
1901 }
1902
1903 /*
1904 * Dup cred struct to a new held one.
1905 */
1906 struct ucred *
1907 crdup(struct ucred *cr)
1908 {
1909 struct ucred *newcr;
1910
1911 newcr = crget();
1912 crcopy(newcr, cr);
1913 return (newcr);
1914 }
1915
1916 /*
1917 * Fill in a struct xucred based on a struct ucred.
1918 */
1919 void
1920 cru2x(struct ucred *cr, struct xucred *xcr)
1921 {
1922 int ngroups;
1923
1924 bzero(xcr, sizeof(*xcr));
1925 xcr->cr_version = XUCRED_VERSION;
1926 xcr->cr_uid = cr->cr_uid;
1927
1928 ngroups = MIN(cr->cr_ngroups, XU_NGROUPS);
1929 xcr->cr_ngroups = ngroups;
1930 bcopy(cr->cr_groups, xcr->cr_groups,
1931 ngroups * sizeof(*cr->cr_groups));
1932 }
1933
1934 /*
1935 * small routine to swap a thread's current ucred for the correct one taken
1936 * from the process.
1937 */
1938 void
1939 cred_update_thread(struct thread *td)
1940 {
1941 struct proc *p;
1942 struct ucred *cred;
1943
1944 p = td->td_proc;
1945 cred = td->td_ucred;
1946 PROC_LOCK(p);
1947 td->td_ucred = crhold(p->p_ucred);
1948 PROC_UNLOCK(p);
1949 if (cred != NULL)
1950 crfree(cred);
1951 }
1952
1953 struct ucred *
1954 crcopysafe(struct proc *p, struct ucred *cr)
1955 {
1956 struct ucred *oldcred;
1957 int groups;
1958
1959 PROC_LOCK_ASSERT(p, MA_OWNED);
1960
1961 oldcred = p->p_ucred;
1962 while (cr->cr_agroups < oldcred->cr_agroups) {
1963 groups = oldcred->cr_agroups;
1964 PROC_UNLOCK(p);
1965 crextend(cr, groups);
1966 PROC_LOCK(p);
1967 oldcred = p->p_ucred;
1968 }
1969 crcopy(cr, oldcred);
1970
1971 return (oldcred);
1972 }
1973
1974 /*
1975 * Extend the passed in credential to hold n items.
1976 */
1977 static void
1978 crextend(struct ucred *cr, int n)
1979 {
1980 int cnt;
1981
1982 /* Truncate? */
1983 if (n <= cr->cr_agroups)
1984 return;
1985
1986 /*
1987 * We extend by 2 each time since we're using a power of two
1988 * allocator until we need enough groups to fill a page.
1989 * Once we're allocating multiple pages, only allocate as many
1990 * as we actually need. The case of processes needing a
1991 * non-power of two number of pages seems more likely than
1992 * a real world process that adds thousands of groups one at a
1993 * time.
1994 */
1995 if ( n < PAGE_SIZE / sizeof(gid_t) ) {
1996 if (cr->cr_agroups == 0)
1997 cnt = MINALLOCSIZE / sizeof(gid_t);
1998 else
1999 cnt = cr->cr_agroups * 2;
2000
2001 while (cnt < n)
2002 cnt *= 2;
2003 } else
2004 cnt = roundup2(n, PAGE_SIZE / sizeof(gid_t));
2005
2006 /* Free the old array. */
2007 if (cr->cr_groups)
2008 free(cr->cr_groups, M_CRED);
2009
2010 cr->cr_groups = malloc(cnt * sizeof(gid_t), M_CRED, M_WAITOK | M_ZERO);
2011 cr->cr_agroups = cnt;
2012 }
2013
2014 /*
2015 * Copy groups in to a credential, preserving any necessary invariants.
2016 * Currently this includes the sorting of all supplemental gids.
2017 * crextend() must have been called before hand to ensure sufficient
2018 * space is available.
2019 */
2020 static void
2021 crsetgroups_locked(struct ucred *cr, int ngrp, gid_t *groups)
2022 {
2023 int i;
2024 int j;
2025 gid_t g;
2026
2027 KASSERT(cr->cr_agroups >= ngrp, ("cr_ngroups is too small"));
2028
2029 bcopy(groups, cr->cr_groups, ngrp * sizeof(gid_t));
2030 cr->cr_ngroups = ngrp;
2031
2032 /*
2033 * Sort all groups except cr_groups[0] to allow groupmember to
2034 * perform a binary search.
2035 *
2036 * XXX: If large numbers of groups become common this should
2037 * be replaced with shell sort like linux uses or possibly
2038 * heap sort.
2039 */
2040 for (i = 2; i < ngrp; i++) {
2041 g = cr->cr_groups[i];
2042 for (j = i-1; j >= 1 && g < cr->cr_groups[j]; j--)
2043 cr->cr_groups[j + 1] = cr->cr_groups[j];
2044 cr->cr_groups[j + 1] = g;
2045 }
2046 }
2047
2048 /*
2049 * Copy groups in to a credential after expanding it if required.
2050 * Truncate the list to (ngroups_max + 1) if it is too large.
2051 */
2052 void
2053 crsetgroups(struct ucred *cr, int ngrp, gid_t *groups)
2054 {
2055
2056 if (ngrp > ngroups_max + 1)
2057 ngrp = ngroups_max + 1;
2058
2059 crextend(cr, ngrp);
2060 crsetgroups_locked(cr, ngrp, groups);
2061 }
2062
2063 /*
2064 * Get login name, if available.
2065 */
2066 #ifndef _SYS_SYSPROTO_H_
2067 struct getlogin_args {
2068 char *namebuf;
2069 u_int namelen;
2070 };
2071 #endif
2072 /* ARGSUSED */
2073 int
2074 sys_getlogin(struct thread *td, struct getlogin_args *uap)
2075 {
2076 char login[MAXLOGNAME];
2077 struct proc *p = td->td_proc;
2078 size_t len;
2079
2080 if (uap->namelen > MAXLOGNAME)
2081 uap->namelen = MAXLOGNAME;
2082 PROC_LOCK(p);
2083 SESS_LOCK(p->p_session);
2084 len = strlcpy(login, p->p_session->s_login, uap->namelen) + 1;
2085 SESS_UNLOCK(p->p_session);
2086 PROC_UNLOCK(p);
2087 if (len > uap->namelen)
2088 return (ERANGE);
2089 return (copyout(login, uap->namebuf, len));
2090 }
2091
2092 /*
2093 * Set login name.
2094 */
2095 #ifndef _SYS_SYSPROTO_H_
2096 struct setlogin_args {
2097 char *namebuf;
2098 };
2099 #endif
2100 /* ARGSUSED */
2101 int
2102 sys_setlogin(struct thread *td, struct setlogin_args *uap)
2103 {
2104 struct proc *p = td->td_proc;
2105 int error;
2106 char logintmp[MAXLOGNAME];
2107
2108 CTASSERT(sizeof(p->p_session->s_login) >= sizeof(logintmp));
2109
2110 error = priv_check(td, PRIV_PROC_SETLOGIN);
2111 if (error)
2112 return (error);
2113 error = copyinstr(uap->namebuf, logintmp, sizeof(logintmp), NULL);
2114 if (error != 0) {
2115 if (error == ENAMETOOLONG)
2116 error = EINVAL;
2117 return (error);
2118 }
2119 PROC_LOCK(p);
2120 SESS_LOCK(p->p_session);
2121 strcpy(p->p_session->s_login, logintmp);
2122 SESS_UNLOCK(p->p_session);
2123 PROC_UNLOCK(p);
2124 return (0);
2125 }
2126
2127 void
2128 setsugid(struct proc *p)
2129 {
2130
2131 PROC_LOCK_ASSERT(p, MA_OWNED);
2132 p->p_flag |= P_SUGID;
2133 if (!(p->p_pfsflags & PF_ISUGID))
2134 p->p_stops = 0;
2135 }
2136
2137 /*-
2138 * Change a process's effective uid.
2139 * Side effects: newcred->cr_uid and newcred->cr_uidinfo will be modified.
2140 * References: newcred must be an exclusive credential reference for the
2141 * duration of the call.
2142 */
2143 void
2144 change_euid(struct ucred *newcred, struct uidinfo *euip)
2145 {
2146
2147 newcred->cr_uid = euip->ui_uid;
2148 uihold(euip);
2149 uifree(newcred->cr_uidinfo);
2150 newcred->cr_uidinfo = euip;
2151 }
2152
2153 /*-
2154 * Change a process's effective gid.
2155 * Side effects: newcred->cr_gid will be modified.
2156 * References: newcred must be an exclusive credential reference for the
2157 * duration of the call.
2158 */
2159 void
2160 change_egid(struct ucred *newcred, gid_t egid)
2161 {
2162
2163 newcred->cr_groups[0] = egid;
2164 }
2165
2166 /*-
2167 * Change a process's real uid.
2168 * Side effects: newcred->cr_ruid will be updated, newcred->cr_ruidinfo
2169 * will be updated, and the old and new cr_ruidinfo proc
2170 * counts will be updated.
2171 * References: newcred must be an exclusive credential reference for the
2172 * duration of the call.
2173 */
2174 void
2175 change_ruid(struct ucred *newcred, struct uidinfo *ruip)
2176 {
2177
2178 (void)chgproccnt(newcred->cr_ruidinfo, -1, 0);
2179 newcred->cr_ruid = ruip->ui_uid;
2180 uihold(ruip);
2181 uifree(newcred->cr_ruidinfo);
2182 newcred->cr_ruidinfo = ruip;
2183 (void)chgproccnt(newcred->cr_ruidinfo, 1, 0);
2184 }
2185
2186 /*-
2187 * Change a process's real gid.
2188 * Side effects: newcred->cr_rgid will be updated.
2189 * References: newcred must be an exclusive credential reference for the
2190 * duration of the call.
2191 */
2192 void
2193 change_rgid(struct ucred *newcred, gid_t rgid)
2194 {
2195
2196 newcred->cr_rgid = rgid;
2197 }
2198
2199 /*-
2200 * Change a process's saved uid.
2201 * Side effects: newcred->cr_svuid will be updated.
2202 * References: newcred must be an exclusive credential reference for the
2203 * duration of the call.
2204 */
2205 void
2206 change_svuid(struct ucred *newcred, uid_t svuid)
2207 {
2208
2209 newcred->cr_svuid = svuid;
2210 }
2211
2212 /*-
2213 * Change a process's saved gid.
2214 * Side effects: newcred->cr_svgid will be updated.
2215 * References: newcred must be an exclusive credential reference for the
2216 * duration of the call.
2217 */
2218 void
2219 change_svgid(struct ucred *newcred, gid_t svgid)
2220 {
2221
2222 newcred->cr_svgid = svgid;
2223 }
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