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/10.1/sys/kern/kern_prot.c 293894 2016-01-14 09:11:16Z glebius $");
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 necessary 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 crsetgroups_locked(struct ucred *cr, int ngrp,
92 gid_t *groups);
93
94 #ifndef _SYS_SYSPROTO_H_
95 struct getpid_args {
96 int dummy;
97 };
98 #endif
99 /* ARGSUSED */
100 int
101 sys_getpid(struct thread *td, struct getpid_args *uap)
102 {
103 struct proc *p = td->td_proc;
104
105 td->td_retval[0] = p->p_pid;
106 #if defined(COMPAT_43)
107 PROC_LOCK(p);
108 td->td_retval[1] = p->p_pptr->p_pid;
109 PROC_UNLOCK(p);
110 #endif
111 return (0);
112 }
113
114 #ifndef _SYS_SYSPROTO_H_
115 struct getppid_args {
116 int dummy;
117 };
118 #endif
119 /* ARGSUSED */
120 int
121 sys_getppid(struct thread *td, struct getppid_args *uap)
122 {
123 struct proc *p = td->td_proc;
124
125 PROC_LOCK(p);
126 td->td_retval[0] = p->p_pptr->p_pid;
127 PROC_UNLOCK(p);
128 return (0);
129 }
130
131 /*
132 * Get process group ID; note that POSIX getpgrp takes no parameter.
133 */
134 #ifndef _SYS_SYSPROTO_H_
135 struct getpgrp_args {
136 int dummy;
137 };
138 #endif
139 int
140 sys_getpgrp(struct thread *td, struct getpgrp_args *uap)
141 {
142 struct proc *p = td->td_proc;
143
144 PROC_LOCK(p);
145 td->td_retval[0] = p->p_pgrp->pg_id;
146 PROC_UNLOCK(p);
147 return (0);
148 }
149
150 /* Get an arbitary pid's process group id */
151 #ifndef _SYS_SYSPROTO_H_
152 struct getpgid_args {
153 pid_t pid;
154 };
155 #endif
156 int
157 sys_getpgid(struct thread *td, struct getpgid_args *uap)
158 {
159 struct proc *p;
160 int error;
161
162 if (uap->pid == 0) {
163 p = td->td_proc;
164 PROC_LOCK(p);
165 } else {
166 p = pfind(uap->pid);
167 if (p == NULL)
168 return (ESRCH);
169 error = p_cansee(td, p);
170 if (error) {
171 PROC_UNLOCK(p);
172 return (error);
173 }
174 }
175 td->td_retval[0] = p->p_pgrp->pg_id;
176 PROC_UNLOCK(p);
177 return (0);
178 }
179
180 /*
181 * Get an arbitary pid's session id.
182 */
183 #ifndef _SYS_SYSPROTO_H_
184 struct getsid_args {
185 pid_t pid;
186 };
187 #endif
188 int
189 sys_getsid(struct thread *td, struct getsid_args *uap)
190 {
191 struct proc *p;
192 int error;
193
194 if (uap->pid == 0) {
195 p = td->td_proc;
196 PROC_LOCK(p);
197 } else {
198 p = pfind(uap->pid);
199 if (p == NULL)
200 return (ESRCH);
201 error = p_cansee(td, p);
202 if (error) {
203 PROC_UNLOCK(p);
204 return (error);
205 }
206 }
207 td->td_retval[0] = p->p_session->s_sid;
208 PROC_UNLOCK(p);
209 return (0);
210 }
211
212 #ifndef _SYS_SYSPROTO_H_
213 struct getuid_args {
214 int dummy;
215 };
216 #endif
217 /* ARGSUSED */
218 int
219 sys_getuid(struct thread *td, struct getuid_args *uap)
220 {
221
222 td->td_retval[0] = td->td_ucred->cr_ruid;
223 #if defined(COMPAT_43)
224 td->td_retval[1] = td->td_ucred->cr_uid;
225 #endif
226 return (0);
227 }
228
229 #ifndef _SYS_SYSPROTO_H_
230 struct geteuid_args {
231 int dummy;
232 };
233 #endif
234 /* ARGSUSED */
235 int
236 sys_geteuid(struct thread *td, struct geteuid_args *uap)
237 {
238
239 td->td_retval[0] = td->td_ucred->cr_uid;
240 return (0);
241 }
242
243 #ifndef _SYS_SYSPROTO_H_
244 struct getgid_args {
245 int dummy;
246 };
247 #endif
248 /* ARGSUSED */
249 int
250 sys_getgid(struct thread *td, struct getgid_args *uap)
251 {
252
253 td->td_retval[0] = td->td_ucred->cr_rgid;
254 #if defined(COMPAT_43)
255 td->td_retval[1] = td->td_ucred->cr_groups[0];
256 #endif
257 return (0);
258 }
259
260 /*
261 * Get effective group ID. The "egid" is groups[0], and could be obtained
262 * via getgroups. This syscall exists because it is somewhat painful to do
263 * correctly in a library function.
264 */
265 #ifndef _SYS_SYSPROTO_H_
266 struct getegid_args {
267 int dummy;
268 };
269 #endif
270 /* ARGSUSED */
271 int
272 sys_getegid(struct thread *td, struct getegid_args *uap)
273 {
274
275 td->td_retval[0] = td->td_ucred->cr_groups[0];
276 return (0);
277 }
278
279 #ifndef _SYS_SYSPROTO_H_
280 struct getgroups_args {
281 u_int gidsetsize;
282 gid_t *gidset;
283 };
284 #endif
285 int
286 sys_getgroups(struct thread *td, register struct getgroups_args *uap)
287 {
288 gid_t *groups;
289 u_int ngrp;
290 int error;
291
292 if (uap->gidsetsize < td->td_ucred->cr_ngroups) {
293 if (uap->gidsetsize == 0)
294 ngrp = 0;
295 else
296 return (EINVAL);
297 } else
298 ngrp = td->td_ucred->cr_ngroups;
299 groups = malloc(ngrp * sizeof(*groups), M_TEMP, M_WAITOK);
300 error = kern_getgroups(td, &ngrp, groups);
301 if (error)
302 goto out;
303 if (uap->gidsetsize > 0)
304 error = copyout(groups, uap->gidset, ngrp * sizeof(gid_t));
305 if (error == 0)
306 td->td_retval[0] = ngrp;
307 out:
308 free(groups, M_TEMP);
309 return (error);
310 }
311
312 int
313 kern_getgroups(struct thread *td, u_int *ngrp, gid_t *groups)
314 {
315 struct ucred *cred;
316
317 cred = td->td_ucred;
318 if (*ngrp == 0) {
319 *ngrp = cred->cr_ngroups;
320 return (0);
321 }
322 if (*ngrp < cred->cr_ngroups)
323 return (EINVAL);
324 *ngrp = cred->cr_ngroups;
325 bcopy(cred->cr_groups, groups, *ngrp * sizeof(gid_t));
326 return (0);
327 }
328
329 #ifndef _SYS_SYSPROTO_H_
330 struct setsid_args {
331 int dummy;
332 };
333 #endif
334 /* ARGSUSED */
335 int
336 sys_setsid(register struct thread *td, struct setsid_args *uap)
337 {
338 struct pgrp *pgrp;
339 int error;
340 struct proc *p = td->td_proc;
341 struct pgrp *newpgrp;
342 struct session *newsess;
343
344 error = 0;
345 pgrp = NULL;
346
347 newpgrp = malloc(sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
348 newsess = malloc(sizeof(struct session), M_SESSION, M_WAITOK | M_ZERO);
349
350 sx_xlock(&proctree_lock);
351
352 if (p->p_pgid == p->p_pid || (pgrp = pgfind(p->p_pid)) != NULL) {
353 if (pgrp != NULL)
354 PGRP_UNLOCK(pgrp);
355 error = EPERM;
356 } else {
357 (void)enterpgrp(p, p->p_pid, newpgrp, newsess);
358 td->td_retval[0] = p->p_pid;
359 newpgrp = NULL;
360 newsess = NULL;
361 }
362
363 sx_xunlock(&proctree_lock);
364
365 if (newpgrp != NULL)
366 free(newpgrp, M_PGRP);
367 if (newsess != NULL)
368 free(newsess, M_SESSION);
369
370 return (error);
371 }
372
373 /*
374 * set process group (setpgid/old setpgrp)
375 *
376 * caller does setpgid(targpid, targpgid)
377 *
378 * pid must be caller or child of caller (ESRCH)
379 * if a child
380 * pid must be in same session (EPERM)
381 * pid can't have done an exec (EACCES)
382 * if pgid != pid
383 * there must exist some pid in same session having pgid (EPERM)
384 * pid must not be session leader (EPERM)
385 */
386 #ifndef _SYS_SYSPROTO_H_
387 struct setpgid_args {
388 int pid; /* target process id */
389 int pgid; /* target pgrp id */
390 };
391 #endif
392 /* ARGSUSED */
393 int
394 sys_setpgid(struct thread *td, register struct setpgid_args *uap)
395 {
396 struct proc *curp = td->td_proc;
397 register struct proc *targp; /* target process */
398 register struct pgrp *pgrp; /* target pgrp */
399 int error;
400 struct pgrp *newpgrp;
401
402 if (uap->pgid < 0)
403 return (EINVAL);
404
405 error = 0;
406
407 newpgrp = malloc(sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
408
409 sx_xlock(&proctree_lock);
410 if (uap->pid != 0 && uap->pid != curp->p_pid) {
411 if ((targp = pfind(uap->pid)) == NULL) {
412 error = ESRCH;
413 goto done;
414 }
415 if (!inferior(targp)) {
416 PROC_UNLOCK(targp);
417 error = ESRCH;
418 goto done;
419 }
420 if ((error = p_cansee(td, targp))) {
421 PROC_UNLOCK(targp);
422 goto done;
423 }
424 if (targp->p_pgrp == NULL ||
425 targp->p_session != curp->p_session) {
426 PROC_UNLOCK(targp);
427 error = EPERM;
428 goto done;
429 }
430 if (targp->p_flag & P_EXEC) {
431 PROC_UNLOCK(targp);
432 error = EACCES;
433 goto done;
434 }
435 PROC_UNLOCK(targp);
436 } else
437 targp = curp;
438 if (SESS_LEADER(targp)) {
439 error = EPERM;
440 goto done;
441 }
442 if (uap->pgid == 0)
443 uap->pgid = targp->p_pid;
444 if ((pgrp = pgfind(uap->pgid)) == NULL) {
445 if (uap->pgid == targp->p_pid) {
446 error = enterpgrp(targp, uap->pgid, newpgrp,
447 NULL);
448 if (error == 0)
449 newpgrp = NULL;
450 } else
451 error = EPERM;
452 } else {
453 if (pgrp == targp->p_pgrp) {
454 PGRP_UNLOCK(pgrp);
455 goto done;
456 }
457 if (pgrp->pg_id != targp->p_pid &&
458 pgrp->pg_session != curp->p_session) {
459 PGRP_UNLOCK(pgrp);
460 error = EPERM;
461 goto done;
462 }
463 PGRP_UNLOCK(pgrp);
464 error = enterthispgrp(targp, pgrp);
465 }
466 done:
467 sx_xunlock(&proctree_lock);
468 KASSERT((error == 0) || (newpgrp != NULL),
469 ("setpgid failed and newpgrp is NULL"));
470 if (newpgrp != NULL)
471 free(newpgrp, M_PGRP);
472 return (error);
473 }
474
475 /*
476 * Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD
477 * compatible. It says that setting the uid/gid to euid/egid is a special
478 * case of "appropriate privilege". Once the rules are expanded out, this
479 * basically means that setuid(nnn) sets all three id's, in all permitted
480 * cases unless _POSIX_SAVED_IDS is enabled. In that case, setuid(getuid())
481 * does not set the saved id - this is dangerous for traditional BSD
482 * programs. For this reason, we *really* do not want to set
483 * _POSIX_SAVED_IDS and do not want to clear POSIX_APPENDIX_B_4_2_2.
484 */
485 #define POSIX_APPENDIX_B_4_2_2
486
487 #ifndef _SYS_SYSPROTO_H_
488 struct setuid_args {
489 uid_t uid;
490 };
491 #endif
492 /* ARGSUSED */
493 int
494 sys_setuid(struct thread *td, struct setuid_args *uap)
495 {
496 struct proc *p = td->td_proc;
497 struct ucred *newcred, *oldcred;
498 uid_t uid;
499 struct uidinfo *uip;
500 int error;
501
502 uid = uap->uid;
503 AUDIT_ARG_UID(uid);
504 newcred = crget();
505 uip = uifind(uid);
506 PROC_LOCK(p);
507 /*
508 * Copy credentials so other references do not see our changes.
509 */
510 oldcred = crcopysafe(p, newcred);
511
512 #ifdef MAC
513 error = mac_cred_check_setuid(oldcred, uid);
514 if (error)
515 goto fail;
516 #endif
517
518 /*
519 * See if we have "permission" by POSIX 1003.1 rules.
520 *
521 * Note that setuid(geteuid()) is a special case of
522 * "appropriate privileges" in appendix B.4.2.2. We need
523 * to use this clause to be compatible with traditional BSD
524 * semantics. Basically, it means that "setuid(xx)" sets all
525 * three id's (assuming you have privs).
526 *
527 * Notes on the logic. We do things in three steps.
528 * 1: We determine if the euid is going to change, and do EPERM
529 * right away. We unconditionally change the euid later if this
530 * test is satisfied, simplifying that part of the logic.
531 * 2: We determine if the real and/or saved uids are going to
532 * change. Determined by compile options.
533 * 3: Change euid last. (after tests in #2 for "appropriate privs")
534 */
535 if (uid != oldcred->cr_ruid && /* allow setuid(getuid()) */
536 #ifdef _POSIX_SAVED_IDS
537 uid != oldcred->cr_svuid && /* allow setuid(saved gid) */
538 #endif
539 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
540 uid != oldcred->cr_uid && /* allow setuid(geteuid()) */
541 #endif
542 (error = priv_check_cred(oldcred, PRIV_CRED_SETUID, 0)) != 0)
543 goto fail;
544
545 #ifdef _POSIX_SAVED_IDS
546 /*
547 * Do we have "appropriate privileges" (are we root or uid == euid)
548 * If so, we are changing the real uid and/or saved uid.
549 */
550 if (
551 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use the clause from B.4.2.2 */
552 uid == oldcred->cr_uid ||
553 #endif
554 /* We are using privs. */
555 priv_check_cred(oldcred, PRIV_CRED_SETUID, 0) == 0)
556 #endif
557 {
558 /*
559 * Set the real uid and transfer proc count to new user.
560 */
561 if (uid != oldcred->cr_ruid) {
562 change_ruid(newcred, uip);
563 setsugid(p);
564 }
565 /*
566 * Set saved uid
567 *
568 * XXX always set saved uid even if not _POSIX_SAVED_IDS, as
569 * the security of seteuid() depends on it. B.4.2.2 says it
570 * is important that we should do this.
571 */
572 if (uid != oldcred->cr_svuid) {
573 change_svuid(newcred, uid);
574 setsugid(p);
575 }
576 }
577
578 /*
579 * In all permitted cases, we are changing the euid.
580 */
581 if (uid != oldcred->cr_uid) {
582 change_euid(newcred, uip);
583 setsugid(p);
584 }
585 p->p_ucred = newcred;
586 PROC_UNLOCK(p);
587 #ifdef RACCT
588 racct_proc_ucred_changed(p, oldcred, newcred);
589 #endif
590 uifree(uip);
591 crfree(oldcred);
592 return (0);
593
594 fail:
595 PROC_UNLOCK(p);
596 uifree(uip);
597 crfree(newcred);
598 return (error);
599 }
600
601 #ifndef _SYS_SYSPROTO_H_
602 struct seteuid_args {
603 uid_t euid;
604 };
605 #endif
606 /* ARGSUSED */
607 int
608 sys_seteuid(struct thread *td, struct seteuid_args *uap)
609 {
610 struct proc *p = td->td_proc;
611 struct ucred *newcred, *oldcred;
612 uid_t euid;
613 struct uidinfo *euip;
614 int error;
615
616 euid = uap->euid;
617 AUDIT_ARG_EUID(euid);
618 newcred = crget();
619 euip = uifind(euid);
620 PROC_LOCK(p);
621 /*
622 * Copy credentials so other references do not see our changes.
623 */
624 oldcred = crcopysafe(p, newcred);
625
626 #ifdef MAC
627 error = mac_cred_check_seteuid(oldcred, euid);
628 if (error)
629 goto fail;
630 #endif
631
632 if (euid != oldcred->cr_ruid && /* allow seteuid(getuid()) */
633 euid != oldcred->cr_svuid && /* allow seteuid(saved uid) */
634 (error = priv_check_cred(oldcred, PRIV_CRED_SETEUID, 0)) != 0)
635 goto fail;
636
637 /*
638 * Everything's okay, do it.
639 */
640 if (oldcred->cr_uid != euid) {
641 change_euid(newcred, euip);
642 setsugid(p);
643 }
644 p->p_ucred = newcred;
645 PROC_UNLOCK(p);
646 uifree(euip);
647 crfree(oldcred);
648 return (0);
649
650 fail:
651 PROC_UNLOCK(p);
652 uifree(euip);
653 crfree(newcred);
654 return (error);
655 }
656
657 #ifndef _SYS_SYSPROTO_H_
658 struct setgid_args {
659 gid_t gid;
660 };
661 #endif
662 /* ARGSUSED */
663 int
664 sys_setgid(struct thread *td, struct setgid_args *uap)
665 {
666 struct proc *p = td->td_proc;
667 struct ucred *newcred, *oldcred;
668 gid_t gid;
669 int error;
670
671 gid = uap->gid;
672 AUDIT_ARG_GID(gid);
673 newcred = crget();
674 PROC_LOCK(p);
675 oldcred = crcopysafe(p, newcred);
676
677 #ifdef MAC
678 error = mac_cred_check_setgid(oldcred, gid);
679 if (error)
680 goto fail;
681 #endif
682
683 /*
684 * See if we have "permission" by POSIX 1003.1 rules.
685 *
686 * Note that setgid(getegid()) is a special case of
687 * "appropriate privileges" in appendix B.4.2.2. We need
688 * to use this clause to be compatible with traditional BSD
689 * semantics. Basically, it means that "setgid(xx)" sets all
690 * three id's (assuming you have privs).
691 *
692 * For notes on the logic here, see setuid() above.
693 */
694 if (gid != oldcred->cr_rgid && /* allow setgid(getgid()) */
695 #ifdef _POSIX_SAVED_IDS
696 gid != oldcred->cr_svgid && /* allow setgid(saved gid) */
697 #endif
698 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
699 gid != oldcred->cr_groups[0] && /* allow setgid(getegid()) */
700 #endif
701 (error = priv_check_cred(oldcred, PRIV_CRED_SETGID, 0)) != 0)
702 goto fail;
703
704 #ifdef _POSIX_SAVED_IDS
705 /*
706 * Do we have "appropriate privileges" (are we root or gid == egid)
707 * If so, we are changing the real uid and saved gid.
708 */
709 if (
710 #ifdef POSIX_APPENDIX_B_4_2_2 /* use the clause from B.4.2.2 */
711 gid == oldcred->cr_groups[0] ||
712 #endif
713 /* We are using privs. */
714 priv_check_cred(oldcred, PRIV_CRED_SETGID, 0) == 0)
715 #endif
716 {
717 /*
718 * Set real gid
719 */
720 if (oldcred->cr_rgid != gid) {
721 change_rgid(newcred, gid);
722 setsugid(p);
723 }
724 /*
725 * Set saved gid
726 *
727 * XXX always set saved gid even if not _POSIX_SAVED_IDS, as
728 * the security of setegid() depends on it. B.4.2.2 says it
729 * is important that we should do this.
730 */
731 if (oldcred->cr_svgid != gid) {
732 change_svgid(newcred, gid);
733 setsugid(p);
734 }
735 }
736 /*
737 * In all cases permitted cases, we are changing the egid.
738 * Copy credentials so other references do not see our changes.
739 */
740 if (oldcred->cr_groups[0] != gid) {
741 change_egid(newcred, gid);
742 setsugid(p);
743 }
744 p->p_ucred = newcred;
745 PROC_UNLOCK(p);
746 crfree(oldcred);
747 return (0);
748
749 fail:
750 PROC_UNLOCK(p);
751 crfree(newcred);
752 return (error);
753 }
754
755 #ifndef _SYS_SYSPROTO_H_
756 struct setegid_args {
757 gid_t egid;
758 };
759 #endif
760 /* ARGSUSED */
761 int
762 sys_setegid(struct thread *td, struct setegid_args *uap)
763 {
764 struct proc *p = td->td_proc;
765 struct ucred *newcred, *oldcred;
766 gid_t egid;
767 int error;
768
769 egid = uap->egid;
770 AUDIT_ARG_EGID(egid);
771 newcred = crget();
772 PROC_LOCK(p);
773 oldcred = crcopysafe(p, newcred);
774
775 #ifdef MAC
776 error = mac_cred_check_setegid(oldcred, egid);
777 if (error)
778 goto fail;
779 #endif
780
781 if (egid != oldcred->cr_rgid && /* allow setegid(getgid()) */
782 egid != oldcred->cr_svgid && /* allow setegid(saved gid) */
783 (error = priv_check_cred(oldcred, PRIV_CRED_SETEGID, 0)) != 0)
784 goto fail;
785
786 if (oldcred->cr_groups[0] != egid) {
787 change_egid(newcred, egid);
788 setsugid(p);
789 }
790 p->p_ucred = newcred;
791 PROC_UNLOCK(p);
792 crfree(oldcred);
793 return (0);
794
795 fail:
796 PROC_UNLOCK(p);
797 crfree(newcred);
798 return (error);
799 }
800
801 #ifndef _SYS_SYSPROTO_H_
802 struct setgroups_args {
803 u_int gidsetsize;
804 gid_t *gidset;
805 };
806 #endif
807 /* ARGSUSED */
808 int
809 sys_setgroups(struct thread *td, struct setgroups_args *uap)
810 {
811 gid_t *groups = NULL;
812 int error;
813
814 if (uap->gidsetsize > ngroups_max + 1)
815 return (EINVAL);
816 groups = malloc(uap->gidsetsize * sizeof(gid_t), M_TEMP, M_WAITOK);
817 error = copyin(uap->gidset, groups, uap->gidsetsize * sizeof(gid_t));
818 if (error)
819 goto out;
820 error = kern_setgroups(td, uap->gidsetsize, groups);
821 out:
822 free(groups, M_TEMP);
823 return (error);
824 }
825
826 int
827 kern_setgroups(struct thread *td, u_int ngrp, gid_t *groups)
828 {
829 struct proc *p = td->td_proc;
830 struct ucred *newcred, *oldcred;
831 int error;
832
833 if (ngrp > ngroups_max + 1)
834 return (EINVAL);
835 AUDIT_ARG_GROUPSET(groups, ngrp);
836 newcred = crget();
837 crextend(newcred, ngrp);
838 PROC_LOCK(p);
839 oldcred = crcopysafe(p, newcred);
840
841 #ifdef MAC
842 error = mac_cred_check_setgroups(oldcred, ngrp, groups);
843 if (error)
844 goto fail;
845 #endif
846
847 error = priv_check_cred(oldcred, PRIV_CRED_SETGROUPS, 0);
848 if (error)
849 goto fail;
850
851 if (ngrp < 1) {
852 /*
853 * setgroups(0, NULL) is a legitimate way of clearing the
854 * groups vector on non-BSD systems (which generally do not
855 * have the egid in the groups[0]). We risk security holes
856 * when running non-BSD software if we do not do the same.
857 */
858 newcred->cr_ngroups = 1;
859 } else {
860 crsetgroups_locked(newcred, ngrp, groups);
861 }
862 setsugid(p);
863 p->p_ucred = newcred;
864 PROC_UNLOCK(p);
865 crfree(oldcred);
866 return (0);
867
868 fail:
869 PROC_UNLOCK(p);
870 crfree(newcred);
871 return (error);
872 }
873
874 #ifndef _SYS_SYSPROTO_H_
875 struct setreuid_args {
876 uid_t ruid;
877 uid_t euid;
878 };
879 #endif
880 /* ARGSUSED */
881 int
882 sys_setreuid(register struct thread *td, struct setreuid_args *uap)
883 {
884 struct proc *p = td->td_proc;
885 struct ucred *newcred, *oldcred;
886 uid_t euid, ruid;
887 struct uidinfo *euip, *ruip;
888 int error;
889
890 euid = uap->euid;
891 ruid = uap->ruid;
892 AUDIT_ARG_EUID(euid);
893 AUDIT_ARG_RUID(ruid);
894 newcred = crget();
895 euip = uifind(euid);
896 ruip = uifind(ruid);
897 PROC_LOCK(p);
898 oldcred = crcopysafe(p, newcred);
899
900 #ifdef MAC
901 error = mac_cred_check_setreuid(oldcred, ruid, euid);
902 if (error)
903 goto fail;
904 #endif
905
906 if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
907 ruid != oldcred->cr_svuid) ||
908 (euid != (uid_t)-1 && euid != oldcred->cr_uid &&
909 euid != oldcred->cr_ruid && euid != oldcred->cr_svuid)) &&
910 (error = priv_check_cred(oldcred, PRIV_CRED_SETREUID, 0)) != 0)
911 goto fail;
912
913 if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
914 change_euid(newcred, euip);
915 setsugid(p);
916 }
917 if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
918 change_ruid(newcred, ruip);
919 setsugid(p);
920 }
921 if ((ruid != (uid_t)-1 || newcred->cr_uid != newcred->cr_ruid) &&
922 newcred->cr_svuid != newcred->cr_uid) {
923 change_svuid(newcred, newcred->cr_uid);
924 setsugid(p);
925 }
926 p->p_ucred = newcred;
927 PROC_UNLOCK(p);
928 #ifdef RACCT
929 racct_proc_ucred_changed(p, oldcred, newcred);
930 #endif
931 uifree(ruip);
932 uifree(euip);
933 crfree(oldcred);
934 return (0);
935
936 fail:
937 PROC_UNLOCK(p);
938 uifree(ruip);
939 uifree(euip);
940 crfree(newcred);
941 return (error);
942 }
943
944 #ifndef _SYS_SYSPROTO_H_
945 struct setregid_args {
946 gid_t rgid;
947 gid_t egid;
948 };
949 #endif
950 /* ARGSUSED */
951 int
952 sys_setregid(register struct thread *td, struct setregid_args *uap)
953 {
954 struct proc *p = td->td_proc;
955 struct ucred *newcred, *oldcred;
956 gid_t egid, rgid;
957 int error;
958
959 egid = uap->egid;
960 rgid = uap->rgid;
961 AUDIT_ARG_EGID(egid);
962 AUDIT_ARG_RGID(rgid);
963 newcred = crget();
964 PROC_LOCK(p);
965 oldcred = crcopysafe(p, newcred);
966
967 #ifdef MAC
968 error = mac_cred_check_setregid(oldcred, rgid, egid);
969 if (error)
970 goto fail;
971 #endif
972
973 if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
974 rgid != oldcred->cr_svgid) ||
975 (egid != (gid_t)-1 && egid != oldcred->cr_groups[0] &&
976 egid != oldcred->cr_rgid && egid != oldcred->cr_svgid)) &&
977 (error = priv_check_cred(oldcred, PRIV_CRED_SETREGID, 0)) != 0)
978 goto fail;
979
980 if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
981 change_egid(newcred, egid);
982 setsugid(p);
983 }
984 if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
985 change_rgid(newcred, rgid);
986 setsugid(p);
987 }
988 if ((rgid != (gid_t)-1 || newcred->cr_groups[0] != newcred->cr_rgid) &&
989 newcred->cr_svgid != newcred->cr_groups[0]) {
990 change_svgid(newcred, newcred->cr_groups[0]);
991 setsugid(p);
992 }
993 p->p_ucred = newcred;
994 PROC_UNLOCK(p);
995 crfree(oldcred);
996 return (0);
997
998 fail:
999 PROC_UNLOCK(p);
1000 crfree(newcred);
1001 return (error);
1002 }
1003
1004 /*
1005 * setresuid(ruid, euid, suid) is like setreuid except control over the saved
1006 * uid is explicit.
1007 */
1008 #ifndef _SYS_SYSPROTO_H_
1009 struct setresuid_args {
1010 uid_t ruid;
1011 uid_t euid;
1012 uid_t suid;
1013 };
1014 #endif
1015 /* ARGSUSED */
1016 int
1017 sys_setresuid(register struct thread *td, struct setresuid_args *uap)
1018 {
1019 struct proc *p = td->td_proc;
1020 struct ucred *newcred, *oldcred;
1021 uid_t euid, ruid, suid;
1022 struct uidinfo *euip, *ruip;
1023 int error;
1024
1025 euid = uap->euid;
1026 ruid = uap->ruid;
1027 suid = uap->suid;
1028 AUDIT_ARG_EUID(euid);
1029 AUDIT_ARG_RUID(ruid);
1030 AUDIT_ARG_SUID(suid);
1031 newcred = crget();
1032 euip = uifind(euid);
1033 ruip = uifind(ruid);
1034 PROC_LOCK(p);
1035 oldcred = crcopysafe(p, newcred);
1036
1037 #ifdef MAC
1038 error = mac_cred_check_setresuid(oldcred, ruid, euid, suid);
1039 if (error)
1040 goto fail;
1041 #endif
1042
1043 if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
1044 ruid != oldcred->cr_svuid &&
1045 ruid != oldcred->cr_uid) ||
1046 (euid != (uid_t)-1 && euid != oldcred->cr_ruid &&
1047 euid != oldcred->cr_svuid &&
1048 euid != oldcred->cr_uid) ||
1049 (suid != (uid_t)-1 && suid != oldcred->cr_ruid &&
1050 suid != oldcred->cr_svuid &&
1051 suid != oldcred->cr_uid)) &&
1052 (error = priv_check_cred(oldcred, PRIV_CRED_SETRESUID, 0)) != 0)
1053 goto fail;
1054
1055 if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
1056 change_euid(newcred, euip);
1057 setsugid(p);
1058 }
1059 if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
1060 change_ruid(newcred, ruip);
1061 setsugid(p);
1062 }
1063 if (suid != (uid_t)-1 && oldcred->cr_svuid != suid) {
1064 change_svuid(newcred, suid);
1065 setsugid(p);
1066 }
1067 p->p_ucred = newcred;
1068 PROC_UNLOCK(p);
1069 #ifdef RACCT
1070 racct_proc_ucred_changed(p, oldcred, newcred);
1071 #endif
1072 uifree(ruip);
1073 uifree(euip);
1074 crfree(oldcred);
1075 return (0);
1076
1077 fail:
1078 PROC_UNLOCK(p);
1079 uifree(ruip);
1080 uifree(euip);
1081 crfree(newcred);
1082 return (error);
1083
1084 }
1085
1086 /*
1087 * setresgid(rgid, egid, sgid) is like setregid except control over the saved
1088 * gid is explicit.
1089 */
1090 #ifndef _SYS_SYSPROTO_H_
1091 struct setresgid_args {
1092 gid_t rgid;
1093 gid_t egid;
1094 gid_t sgid;
1095 };
1096 #endif
1097 /* ARGSUSED */
1098 int
1099 sys_setresgid(register struct thread *td, struct setresgid_args *uap)
1100 {
1101 struct proc *p = td->td_proc;
1102 struct ucred *newcred, *oldcred;
1103 gid_t egid, rgid, sgid;
1104 int error;
1105
1106 egid = uap->egid;
1107 rgid = uap->rgid;
1108 sgid = uap->sgid;
1109 AUDIT_ARG_EGID(egid);
1110 AUDIT_ARG_RGID(rgid);
1111 AUDIT_ARG_SGID(sgid);
1112 newcred = crget();
1113 PROC_LOCK(p);
1114 oldcred = crcopysafe(p, newcred);
1115
1116 #ifdef MAC
1117 error = mac_cred_check_setresgid(oldcred, rgid, egid, sgid);
1118 if (error)
1119 goto fail;
1120 #endif
1121
1122 if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
1123 rgid != oldcred->cr_svgid &&
1124 rgid != oldcred->cr_groups[0]) ||
1125 (egid != (gid_t)-1 && egid != oldcred->cr_rgid &&
1126 egid != oldcred->cr_svgid &&
1127 egid != oldcred->cr_groups[0]) ||
1128 (sgid != (gid_t)-1 && sgid != oldcred->cr_rgid &&
1129 sgid != oldcred->cr_svgid &&
1130 sgid != oldcred->cr_groups[0])) &&
1131 (error = priv_check_cred(oldcred, PRIV_CRED_SETRESGID, 0)) != 0)
1132 goto fail;
1133
1134 if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
1135 change_egid(newcred, egid);
1136 setsugid(p);
1137 }
1138 if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
1139 change_rgid(newcred, rgid);
1140 setsugid(p);
1141 }
1142 if (sgid != (gid_t)-1 && oldcred->cr_svgid != sgid) {
1143 change_svgid(newcred, sgid);
1144 setsugid(p);
1145 }
1146 p->p_ucred = newcred;
1147 PROC_UNLOCK(p);
1148 crfree(oldcred);
1149 return (0);
1150
1151 fail:
1152 PROC_UNLOCK(p);
1153 crfree(newcred);
1154 return (error);
1155 }
1156
1157 #ifndef _SYS_SYSPROTO_H_
1158 struct getresuid_args {
1159 uid_t *ruid;
1160 uid_t *euid;
1161 uid_t *suid;
1162 };
1163 #endif
1164 /* ARGSUSED */
1165 int
1166 sys_getresuid(register struct thread *td, struct getresuid_args *uap)
1167 {
1168 struct ucred *cred;
1169 int error1 = 0, error2 = 0, error3 = 0;
1170
1171 cred = td->td_ucred;
1172 if (uap->ruid)
1173 error1 = copyout(&cred->cr_ruid,
1174 uap->ruid, sizeof(cred->cr_ruid));
1175 if (uap->euid)
1176 error2 = copyout(&cred->cr_uid,
1177 uap->euid, sizeof(cred->cr_uid));
1178 if (uap->suid)
1179 error3 = copyout(&cred->cr_svuid,
1180 uap->suid, sizeof(cred->cr_svuid));
1181 return (error1 ? error1 : error2 ? error2 : error3);
1182 }
1183
1184 #ifndef _SYS_SYSPROTO_H_
1185 struct getresgid_args {
1186 gid_t *rgid;
1187 gid_t *egid;
1188 gid_t *sgid;
1189 };
1190 #endif
1191 /* ARGSUSED */
1192 int
1193 sys_getresgid(register struct thread *td, struct getresgid_args *uap)
1194 {
1195 struct ucred *cred;
1196 int error1 = 0, error2 = 0, error3 = 0;
1197
1198 cred = td->td_ucred;
1199 if (uap->rgid)
1200 error1 = copyout(&cred->cr_rgid,
1201 uap->rgid, sizeof(cred->cr_rgid));
1202 if (uap->egid)
1203 error2 = copyout(&cred->cr_groups[0],
1204 uap->egid, sizeof(cred->cr_groups[0]));
1205 if (uap->sgid)
1206 error3 = copyout(&cred->cr_svgid,
1207 uap->sgid, sizeof(cred->cr_svgid));
1208 return (error1 ? error1 : error2 ? error2 : error3);
1209 }
1210
1211 #ifndef _SYS_SYSPROTO_H_
1212 struct issetugid_args {
1213 int dummy;
1214 };
1215 #endif
1216 /* ARGSUSED */
1217 int
1218 sys_issetugid(register struct thread *td, struct issetugid_args *uap)
1219 {
1220 struct proc *p = td->td_proc;
1221
1222 /*
1223 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
1224 * we use P_SUGID because we consider changing the owners as
1225 * "tainting" as well.
1226 * This is significant for procs that start as root and "become"
1227 * a user without an exec - programs cannot know *everything*
1228 * that libc *might* have put in their data segment.
1229 */
1230 PROC_LOCK(p);
1231 td->td_retval[0] = (p->p_flag & P_SUGID) ? 1 : 0;
1232 PROC_UNLOCK(p);
1233 return (0);
1234 }
1235
1236 int
1237 sys___setugid(struct thread *td, struct __setugid_args *uap)
1238 {
1239 #ifdef REGRESSION
1240 struct proc *p;
1241
1242 p = td->td_proc;
1243 switch (uap->flag) {
1244 case 0:
1245 PROC_LOCK(p);
1246 p->p_flag &= ~P_SUGID;
1247 PROC_UNLOCK(p);
1248 return (0);
1249 case 1:
1250 PROC_LOCK(p);
1251 p->p_flag |= P_SUGID;
1252 PROC_UNLOCK(p);
1253 return (0);
1254 default:
1255 return (EINVAL);
1256 }
1257 #else /* !REGRESSION */
1258
1259 return (ENOSYS);
1260 #endif /* REGRESSION */
1261 }
1262
1263 /*
1264 * Check if gid is a member of the group set.
1265 */
1266 int
1267 groupmember(gid_t gid, struct ucred *cred)
1268 {
1269 int l;
1270 int h;
1271 int m;
1272
1273 if (cred->cr_groups[0] == gid)
1274 return(1);
1275
1276 /*
1277 * If gid was not our primary group, perform a binary search
1278 * of the supplemental groups. This is possible because we
1279 * sort the groups in crsetgroups().
1280 */
1281 l = 1;
1282 h = cred->cr_ngroups;
1283 while (l < h) {
1284 m = l + ((h - l) / 2);
1285 if (cred->cr_groups[m] < gid)
1286 l = m + 1;
1287 else
1288 h = m;
1289 }
1290 if ((l < cred->cr_ngroups) && (cred->cr_groups[l] == gid))
1291 return (1);
1292
1293 return (0);
1294 }
1295
1296 /*
1297 * Test the active securelevel against a given level. securelevel_gt()
1298 * implements (securelevel > level). securelevel_ge() implements
1299 * (securelevel >= level). Note that the logic is inverted -- these
1300 * functions return EPERM on "success" and 0 on "failure".
1301 *
1302 * Due to care taken when setting the securelevel, we know that no jail will
1303 * be less secure that its parent (or the physical system), so it is sufficient
1304 * to test the current jail only.
1305 *
1306 * XXXRW: Possibly since this has to do with privilege, it should move to
1307 * kern_priv.c.
1308 */
1309 int
1310 securelevel_gt(struct ucred *cr, int level)
1311 {
1312
1313 return (cr->cr_prison->pr_securelevel > level ? EPERM : 0);
1314 }
1315
1316 int
1317 securelevel_ge(struct ucred *cr, int level)
1318 {
1319
1320 return (cr->cr_prison->pr_securelevel >= level ? EPERM : 0);
1321 }
1322
1323 /*
1324 * 'see_other_uids' determines whether or not visibility of processes
1325 * and sockets with credentials holding different real uids is possible
1326 * using a variety of system MIBs.
1327 * XXX: data declarations should be together near the beginning of the file.
1328 */
1329 static int see_other_uids = 1;
1330 SYSCTL_INT(_security_bsd, OID_AUTO, see_other_uids, CTLFLAG_RW,
1331 &see_other_uids, 0,
1332 "Unprivileged processes may see subjects/objects with different real uid");
1333
1334 /*-
1335 * Determine if u1 "can see" the subject specified by u2, according to the
1336 * 'see_other_uids' policy.
1337 * Returns: 0 for permitted, ESRCH otherwise
1338 * Locks: none
1339 * References: *u1 and *u2 must not change during the call
1340 * u1 may equal u2, in which case only one reference is required
1341 */
1342 static int
1343 cr_seeotheruids(struct ucred *u1, struct ucred *u2)
1344 {
1345
1346 if (!see_other_uids && u1->cr_ruid != u2->cr_ruid) {
1347 if (priv_check_cred(u1, PRIV_SEEOTHERUIDS, 0) != 0)
1348 return (ESRCH);
1349 }
1350 return (0);
1351 }
1352
1353 /*
1354 * 'see_other_gids' determines whether or not visibility of processes
1355 * and sockets with credentials holding different real gids is possible
1356 * using a variety of system MIBs.
1357 * XXX: data declarations should be together near the beginning of the file.
1358 */
1359 static int see_other_gids = 1;
1360 SYSCTL_INT(_security_bsd, OID_AUTO, see_other_gids, CTLFLAG_RW,
1361 &see_other_gids, 0,
1362 "Unprivileged processes may see subjects/objects with different real gid");
1363
1364 /*
1365 * Determine if u1 can "see" the subject specified by u2, according to the
1366 * 'see_other_gids' policy.
1367 * Returns: 0 for permitted, ESRCH otherwise
1368 * Locks: none
1369 * References: *u1 and *u2 must not change during the call
1370 * u1 may equal u2, in which case only one reference is required
1371 */
1372 static int
1373 cr_seeothergids(struct ucred *u1, struct ucred *u2)
1374 {
1375 int i, match;
1376
1377 if (!see_other_gids) {
1378 match = 0;
1379 for (i = 0; i < u1->cr_ngroups; i++) {
1380 if (groupmember(u1->cr_groups[i], u2))
1381 match = 1;
1382 if (match)
1383 break;
1384 }
1385 if (!match) {
1386 if (priv_check_cred(u1, PRIV_SEEOTHERGIDS, 0) != 0)
1387 return (ESRCH);
1388 }
1389 }
1390 return (0);
1391 }
1392
1393 /*-
1394 * Determine if u1 "can see" the subject specified by u2.
1395 * Returns: 0 for permitted, an errno value otherwise
1396 * Locks: none
1397 * References: *u1 and *u2 must not change during the call
1398 * u1 may equal u2, in which case only one reference is required
1399 */
1400 int
1401 cr_cansee(struct ucred *u1, struct ucred *u2)
1402 {
1403 int error;
1404
1405 if ((error = prison_check(u1, u2)))
1406 return (error);
1407 #ifdef MAC
1408 if ((error = mac_cred_check_visible(u1, u2)))
1409 return (error);
1410 #endif
1411 if ((error = cr_seeotheruids(u1, u2)))
1412 return (error);
1413 if ((error = cr_seeothergids(u1, u2)))
1414 return (error);
1415 return (0);
1416 }
1417
1418 /*-
1419 * Determine if td "can see" the subject specified by p.
1420 * Returns: 0 for permitted, an errno value otherwise
1421 * Locks: Sufficient locks to protect p->p_ucred must be held. td really
1422 * should be curthread.
1423 * References: td and p must be valid for the lifetime of the call
1424 */
1425 int
1426 p_cansee(struct thread *td, struct proc *p)
1427 {
1428
1429 /* Wrap cr_cansee() for all functionality. */
1430 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1431 PROC_LOCK_ASSERT(p, MA_OWNED);
1432 return (cr_cansee(td->td_ucred, p->p_ucred));
1433 }
1434
1435 /*
1436 * 'conservative_signals' prevents the delivery of a broad class of
1437 * signals by unprivileged processes to processes that have changed their
1438 * credentials since the last invocation of execve(). This can prevent
1439 * the leakage of cached information or retained privileges as a result
1440 * of a common class of signal-related vulnerabilities. However, this
1441 * may interfere with some applications that expect to be able to
1442 * deliver these signals to peer processes after having given up
1443 * privilege.
1444 */
1445 static int conservative_signals = 1;
1446 SYSCTL_INT(_security_bsd, OID_AUTO, conservative_signals, CTLFLAG_RW,
1447 &conservative_signals, 0, "Unprivileged processes prevented from "
1448 "sending certain signals to processes whose credentials have changed");
1449 /*-
1450 * Determine whether cred may deliver the specified signal to proc.
1451 * Returns: 0 for permitted, an errno value otherwise.
1452 * Locks: A lock must be held for proc.
1453 * References: cred and proc must be valid for the lifetime of the call.
1454 */
1455 int
1456 cr_cansignal(struct ucred *cred, struct proc *proc, int signum)
1457 {
1458 int error;
1459
1460 PROC_LOCK_ASSERT(proc, MA_OWNED);
1461 /*
1462 * Jail semantics limit the scope of signalling to proc in the
1463 * same jail as cred, if cred is in jail.
1464 */
1465 error = prison_check(cred, proc->p_ucred);
1466 if (error)
1467 return (error);
1468 #ifdef MAC
1469 if ((error = mac_proc_check_signal(cred, proc, signum)))
1470 return (error);
1471 #endif
1472 if ((error = cr_seeotheruids(cred, proc->p_ucred)))
1473 return (error);
1474 if ((error = cr_seeothergids(cred, proc->p_ucred)))
1475 return (error);
1476
1477 /*
1478 * UNIX signal semantics depend on the status of the P_SUGID
1479 * bit on the target process. If the bit is set, then additional
1480 * restrictions are placed on the set of available signals.
1481 */
1482 if (conservative_signals && (proc->p_flag & P_SUGID)) {
1483 switch (signum) {
1484 case 0:
1485 case SIGKILL:
1486 case SIGINT:
1487 case SIGTERM:
1488 case SIGALRM:
1489 case SIGSTOP:
1490 case SIGTTIN:
1491 case SIGTTOU:
1492 case SIGTSTP:
1493 case SIGHUP:
1494 case SIGUSR1:
1495 case SIGUSR2:
1496 /*
1497 * Generally, permit job and terminal control
1498 * signals.
1499 */
1500 break;
1501 default:
1502 /* Not permitted without privilege. */
1503 error = priv_check_cred(cred, PRIV_SIGNAL_SUGID, 0);
1504 if (error)
1505 return (error);
1506 }
1507 }
1508
1509 /*
1510 * Generally, the target credential's ruid or svuid must match the
1511 * subject credential's ruid or euid.
1512 */
1513 if (cred->cr_ruid != proc->p_ucred->cr_ruid &&
1514 cred->cr_ruid != proc->p_ucred->cr_svuid &&
1515 cred->cr_uid != proc->p_ucred->cr_ruid &&
1516 cred->cr_uid != proc->p_ucred->cr_svuid) {
1517 error = priv_check_cred(cred, PRIV_SIGNAL_DIFFCRED, 0);
1518 if (error)
1519 return (error);
1520 }
1521
1522 return (0);
1523 }
1524
1525 /*-
1526 * Determine whether td may deliver the specified signal to p.
1527 * Returns: 0 for permitted, an errno value otherwise
1528 * Locks: Sufficient locks to protect various components of td and p
1529 * must be held. td must be curthread, and a lock must be
1530 * held for p.
1531 * References: td and p must be valid for the lifetime of the call
1532 */
1533 int
1534 p_cansignal(struct thread *td, struct proc *p, int signum)
1535 {
1536
1537 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1538 PROC_LOCK_ASSERT(p, MA_OWNED);
1539 if (td->td_proc == p)
1540 return (0);
1541
1542 /*
1543 * UNIX signalling semantics require that processes in the same
1544 * session always be able to deliver SIGCONT to one another,
1545 * overriding the remaining protections.
1546 */
1547 /* XXX: This will require an additional lock of some sort. */
1548 if (signum == SIGCONT && td->td_proc->p_session == p->p_session)
1549 return (0);
1550 /*
1551 * Some compat layers use SIGTHR and higher signals for
1552 * communication between different kernel threads of the same
1553 * process, so that they expect that it's always possible to
1554 * deliver them, even for suid applications where cr_cansignal() can
1555 * deny such ability for security consideration. It should be
1556 * pretty safe to do since the only way to create two processes
1557 * with the same p_leader is via rfork(2).
1558 */
1559 if (td->td_proc->p_leader != NULL && signum >= SIGTHR &&
1560 signum < SIGTHR + 4 && td->td_proc->p_leader == p->p_leader)
1561 return (0);
1562
1563 return (cr_cansignal(td->td_ucred, p, signum));
1564 }
1565
1566 /*-
1567 * Determine whether td may reschedule p.
1568 * Returns: 0 for permitted, an errno value otherwise
1569 * Locks: Sufficient locks to protect various components of td and p
1570 * must be held. td must be curthread, and a lock must
1571 * be held for p.
1572 * References: td and p must be valid for the lifetime of the call
1573 */
1574 int
1575 p_cansched(struct thread *td, struct proc *p)
1576 {
1577 int error;
1578
1579 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1580 PROC_LOCK_ASSERT(p, MA_OWNED);
1581 if (td->td_proc == p)
1582 return (0);
1583 if ((error = prison_check(td->td_ucred, p->p_ucred)))
1584 return (error);
1585 #ifdef MAC
1586 if ((error = mac_proc_check_sched(td->td_ucred, p)))
1587 return (error);
1588 #endif
1589 if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
1590 return (error);
1591 if ((error = cr_seeothergids(td->td_ucred, p->p_ucred)))
1592 return (error);
1593 if (td->td_ucred->cr_ruid != p->p_ucred->cr_ruid &&
1594 td->td_ucred->cr_uid != p->p_ucred->cr_ruid) {
1595 error = priv_check(td, PRIV_SCHED_DIFFCRED);
1596 if (error)
1597 return (error);
1598 }
1599 return (0);
1600 }
1601
1602 /*
1603 * The 'unprivileged_proc_debug' flag may be used to disable a variety of
1604 * unprivileged inter-process debugging services, including some procfs
1605 * functionality, ptrace(), and ktrace(). In the past, inter-process
1606 * debugging has been involved in a variety of security problems, and sites
1607 * not requiring the service might choose to disable it when hardening
1608 * systems.
1609 *
1610 * XXX: Should modifying and reading this variable require locking?
1611 * XXX: data declarations should be together near the beginning of the file.
1612 */
1613 static int unprivileged_proc_debug = 1;
1614 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_proc_debug, CTLFLAG_RW,
1615 &unprivileged_proc_debug, 0,
1616 "Unprivileged processes may use process debugging facilities");
1617
1618 /*-
1619 * Determine whether td may debug p.
1620 * Returns: 0 for permitted, an errno value otherwise
1621 * Locks: Sufficient locks to protect various components of td and p
1622 * must be held. td must be curthread, and a lock must
1623 * be held for p.
1624 * References: td and p must be valid for the lifetime of the call
1625 */
1626 int
1627 p_candebug(struct thread *td, struct proc *p)
1628 {
1629 int credentialchanged, error, grpsubset, i, uidsubset;
1630
1631 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1632 PROC_LOCK_ASSERT(p, MA_OWNED);
1633 if (!unprivileged_proc_debug) {
1634 error = priv_check(td, PRIV_DEBUG_UNPRIV);
1635 if (error)
1636 return (error);
1637 }
1638 if (td->td_proc == p)
1639 return (0);
1640 if ((error = prison_check(td->td_ucred, p->p_ucred)))
1641 return (error);
1642 #ifdef MAC
1643 if ((error = mac_proc_check_debug(td->td_ucred, p)))
1644 return (error);
1645 #endif
1646 if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
1647 return (error);
1648 if ((error = cr_seeothergids(td->td_ucred, p->p_ucred)))
1649 return (error);
1650
1651 /*
1652 * Is p's group set a subset of td's effective group set? This
1653 * includes p's egid, group access list, rgid, and svgid.
1654 */
1655 grpsubset = 1;
1656 for (i = 0; i < p->p_ucred->cr_ngroups; i++) {
1657 if (!groupmember(p->p_ucred->cr_groups[i], td->td_ucred)) {
1658 grpsubset = 0;
1659 break;
1660 }
1661 }
1662 grpsubset = grpsubset &&
1663 groupmember(p->p_ucred->cr_rgid, td->td_ucred) &&
1664 groupmember(p->p_ucred->cr_svgid, td->td_ucred);
1665
1666 /*
1667 * Are the uids present in p's credential equal to td's
1668 * effective uid? This includes p's euid, svuid, and ruid.
1669 */
1670 uidsubset = (td->td_ucred->cr_uid == p->p_ucred->cr_uid &&
1671 td->td_ucred->cr_uid == p->p_ucred->cr_svuid &&
1672 td->td_ucred->cr_uid == p->p_ucred->cr_ruid);
1673
1674 /*
1675 * Has the credential of the process changed since the last exec()?
1676 */
1677 credentialchanged = (p->p_flag & P_SUGID);
1678
1679 /*
1680 * If p's gids aren't a subset, or the uids aren't a subset,
1681 * or the credential has changed, require appropriate privilege
1682 * for td to debug p.
1683 */
1684 if (!grpsubset || !uidsubset) {
1685 error = priv_check(td, PRIV_DEBUG_DIFFCRED);
1686 if (error)
1687 return (error);
1688 }
1689
1690 if (credentialchanged) {
1691 error = priv_check(td, PRIV_DEBUG_SUGID);
1692 if (error)
1693 return (error);
1694 }
1695
1696 /* Can't trace init when securelevel > 0. */
1697 if (p == initproc) {
1698 error = securelevel_gt(td->td_ucred, 0);
1699 if (error)
1700 return (error);
1701 }
1702
1703 /*
1704 * Can't trace a process that's currently exec'ing.
1705 *
1706 * XXX: Note, this is not a security policy decision, it's a
1707 * basic correctness/functionality decision. Therefore, this check
1708 * should be moved to the caller's of p_candebug().
1709 */
1710 if ((p->p_flag & P_INEXEC) != 0)
1711 return (EBUSY);
1712
1713 return (0);
1714 }
1715
1716 /*-
1717 * Determine whether the subject represented by cred can "see" a socket.
1718 * Returns: 0 for permitted, ENOENT otherwise.
1719 */
1720 int
1721 cr_canseesocket(struct ucred *cred, struct socket *so)
1722 {
1723 int error;
1724
1725 error = prison_check(cred, so->so_cred);
1726 if (error)
1727 return (ENOENT);
1728 #ifdef MAC
1729 error = mac_socket_check_visible(cred, so);
1730 if (error)
1731 return (error);
1732 #endif
1733 if (cr_seeotheruids(cred, so->so_cred))
1734 return (ENOENT);
1735 if (cr_seeothergids(cred, so->so_cred))
1736 return (ENOENT);
1737
1738 return (0);
1739 }
1740
1741 #if defined(INET) || defined(INET6)
1742 /*-
1743 * Determine whether the subject represented by cred can "see" a socket.
1744 * Returns: 0 for permitted, ENOENT otherwise.
1745 */
1746 int
1747 cr_canseeinpcb(struct ucred *cred, struct inpcb *inp)
1748 {
1749 int error;
1750
1751 error = prison_check(cred, inp->inp_cred);
1752 if (error)
1753 return (ENOENT);
1754 #ifdef MAC
1755 INP_LOCK_ASSERT(inp);
1756 error = mac_inpcb_check_visible(cred, inp);
1757 if (error)
1758 return (error);
1759 #endif
1760 if (cr_seeotheruids(cred, inp->inp_cred))
1761 return (ENOENT);
1762 if (cr_seeothergids(cred, inp->inp_cred))
1763 return (ENOENT);
1764
1765 return (0);
1766 }
1767 #endif
1768
1769 /*-
1770 * Determine whether td can wait for the exit of p.
1771 * Returns: 0 for permitted, an errno value otherwise
1772 * Locks: Sufficient locks to protect various components of td and p
1773 * must be held. td must be curthread, and a lock must
1774 * be held for p.
1775 * References: td and p must be valid for the lifetime of the call
1776
1777 */
1778 int
1779 p_canwait(struct thread *td, struct proc *p)
1780 {
1781 int error;
1782
1783 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1784 PROC_LOCK_ASSERT(p, MA_OWNED);
1785 if ((error = prison_check(td->td_ucred, p->p_ucred)))
1786 return (error);
1787 #ifdef MAC
1788 if ((error = mac_proc_check_wait(td->td_ucred, p)))
1789 return (error);
1790 #endif
1791 #if 0
1792 /* XXXMAC: This could have odd effects on some shells. */
1793 if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
1794 return (error);
1795 #endif
1796
1797 return (0);
1798 }
1799
1800 /*
1801 * Allocate a zeroed cred structure.
1802 */
1803 struct ucred *
1804 crget(void)
1805 {
1806 register struct ucred *cr;
1807
1808 cr = malloc(sizeof(*cr), M_CRED, M_WAITOK | M_ZERO);
1809 refcount_init(&cr->cr_ref, 1);
1810 #ifdef AUDIT
1811 audit_cred_init(cr);
1812 #endif
1813 #ifdef MAC
1814 mac_cred_init(cr);
1815 #endif
1816 crextend(cr, XU_NGROUPS);
1817 return (cr);
1818 }
1819
1820 /*
1821 * Claim another reference to a ucred structure.
1822 */
1823 struct ucred *
1824 crhold(struct ucred *cr)
1825 {
1826
1827 refcount_acquire(&cr->cr_ref);
1828 return (cr);
1829 }
1830
1831 /*
1832 * Free a cred structure. Throws away space when ref count gets to 0.
1833 */
1834 void
1835 crfree(struct ucred *cr)
1836 {
1837
1838 KASSERT(cr->cr_ref > 0, ("bad ucred refcount: %d", cr->cr_ref));
1839 KASSERT(cr->cr_ref != 0xdeadc0de, ("dangling reference to ucred"));
1840 if (refcount_release(&cr->cr_ref)) {
1841 /*
1842 * Some callers of crget(), such as nfs_statfs(),
1843 * allocate a temporary credential, but don't
1844 * allocate a uidinfo structure.
1845 */
1846 if (cr->cr_uidinfo != NULL)
1847 uifree(cr->cr_uidinfo);
1848 if (cr->cr_ruidinfo != NULL)
1849 uifree(cr->cr_ruidinfo);
1850 /*
1851 * Free a prison, if any.
1852 */
1853 if (cr->cr_prison != NULL)
1854 prison_free(cr->cr_prison);
1855 if (cr->cr_loginclass != NULL)
1856 loginclass_free(cr->cr_loginclass);
1857 #ifdef AUDIT
1858 audit_cred_destroy(cr);
1859 #endif
1860 #ifdef MAC
1861 mac_cred_destroy(cr);
1862 #endif
1863 free(cr->cr_groups, M_CRED);
1864 free(cr, M_CRED);
1865 }
1866 }
1867
1868 /*
1869 * Check to see if this ucred is shared.
1870 */
1871 int
1872 crshared(struct ucred *cr)
1873 {
1874
1875 return (cr->cr_ref > 1);
1876 }
1877
1878 /*
1879 * Copy a ucred's contents from a template. Does not block.
1880 */
1881 void
1882 crcopy(struct ucred *dest, struct ucred *src)
1883 {
1884
1885 KASSERT(crshared(dest) == 0, ("crcopy of shared ucred"));
1886 bcopy(&src->cr_startcopy, &dest->cr_startcopy,
1887 (unsigned)((caddr_t)&src->cr_endcopy -
1888 (caddr_t)&src->cr_startcopy));
1889 crsetgroups(dest, src->cr_ngroups, src->cr_groups);
1890 uihold(dest->cr_uidinfo);
1891 uihold(dest->cr_ruidinfo);
1892 prison_hold(dest->cr_prison);
1893 loginclass_hold(dest->cr_loginclass);
1894 #ifdef AUDIT
1895 audit_cred_copy(src, dest);
1896 #endif
1897 #ifdef MAC
1898 mac_cred_copy(src, dest);
1899 #endif
1900 }
1901
1902 /*
1903 * Dup cred struct to a new held one.
1904 */
1905 struct ucred *
1906 crdup(struct ucred *cr)
1907 {
1908 struct ucred *newcr;
1909
1910 newcr = crget();
1911 crcopy(newcr, cr);
1912 return (newcr);
1913 }
1914
1915 /*
1916 * Fill in a struct xucred based on a struct ucred.
1917 */
1918 void
1919 cru2x(struct ucred *cr, struct xucred *xcr)
1920 {
1921 int ngroups;
1922
1923 bzero(xcr, sizeof(*xcr));
1924 xcr->cr_version = XUCRED_VERSION;
1925 xcr->cr_uid = cr->cr_uid;
1926
1927 ngroups = MIN(cr->cr_ngroups, XU_NGROUPS);
1928 xcr->cr_ngroups = ngroups;
1929 bcopy(cr->cr_groups, xcr->cr_groups,
1930 ngroups * sizeof(*cr->cr_groups));
1931 }
1932
1933 /*
1934 * small routine to swap a thread's current ucred for the correct one taken
1935 * from the process.
1936 */
1937 void
1938 cred_update_thread(struct thread *td)
1939 {
1940 struct proc *p;
1941 struct ucred *cred;
1942
1943 p = td->td_proc;
1944 cred = td->td_ucred;
1945 PROC_LOCK(p);
1946 td->td_ucred = crhold(p->p_ucred);
1947 PROC_UNLOCK(p);
1948 if (cred != NULL)
1949 crfree(cred);
1950 }
1951
1952 struct ucred *
1953 crcopysafe(struct proc *p, struct ucred *cr)
1954 {
1955 struct ucred *oldcred;
1956 int groups;
1957
1958 PROC_LOCK_ASSERT(p, MA_OWNED);
1959
1960 oldcred = p->p_ucred;
1961 while (cr->cr_agroups < oldcred->cr_agroups) {
1962 groups = oldcred->cr_agroups;
1963 PROC_UNLOCK(p);
1964 crextend(cr, groups);
1965 PROC_LOCK(p);
1966 oldcred = p->p_ucred;
1967 }
1968 crcopy(cr, oldcred);
1969
1970 return (oldcred);
1971 }
1972
1973 /*
1974 * Extend the passed in credential to hold n items.
1975 */
1976 void
1977 crextend(struct ucred *cr, int n)
1978 {
1979 int cnt;
1980
1981 /* Truncate? */
1982 if (n <= cr->cr_agroups)
1983 return;
1984
1985 /*
1986 * We extend by 2 each time since we're using a power of two
1987 * allocator until we need enough groups to fill a page.
1988 * Once we're allocating multiple pages, only allocate as many
1989 * as we actually need. The case of processes needing a
1990 * non-power of two number of pages seems more likely than
1991 * a real world process that adds thousands of groups one at a
1992 * time.
1993 */
1994 if ( n < PAGE_SIZE / sizeof(gid_t) ) {
1995 if (cr->cr_agroups == 0)
1996 cnt = MINALLOCSIZE / sizeof(gid_t);
1997 else
1998 cnt = cr->cr_agroups * 2;
1999
2000 while (cnt < n)
2001 cnt *= 2;
2002 } else
2003 cnt = roundup2(n, PAGE_SIZE / sizeof(gid_t));
2004
2005 /* Free the old array. */
2006 if (cr->cr_groups)
2007 free(cr->cr_groups, M_CRED);
2008
2009 cr->cr_groups = malloc(cnt * sizeof(gid_t), M_CRED, M_WAITOK | M_ZERO);
2010 cr->cr_agroups = cnt;
2011 }
2012
2013 /*
2014 * Copy groups in to a credential, preserving any necessary invariants.
2015 * Currently this includes the sorting of all supplemental gids.
2016 * crextend() must have been called before hand to ensure sufficient
2017 * space is available.
2018 */
2019 static void
2020 crsetgroups_locked(struct ucred *cr, int ngrp, gid_t *groups)
2021 {
2022 int i;
2023 int j;
2024 gid_t g;
2025
2026 KASSERT(cr->cr_agroups >= ngrp, ("cr_ngroups is too small"));
2027
2028 bcopy(groups, cr->cr_groups, ngrp * sizeof(gid_t));
2029 cr->cr_ngroups = ngrp;
2030
2031 /*
2032 * Sort all groups except cr_groups[0] to allow groupmember to
2033 * perform a binary search.
2034 *
2035 * XXX: If large numbers of groups become common this should
2036 * be replaced with shell sort like linux uses or possibly
2037 * heap sort.
2038 */
2039 for (i = 2; i < ngrp; i++) {
2040 g = cr->cr_groups[i];
2041 for (j = i-1; j >= 1 && g < cr->cr_groups[j]; j--)
2042 cr->cr_groups[j + 1] = cr->cr_groups[j];
2043 cr->cr_groups[j + 1] = g;
2044 }
2045 }
2046
2047 /*
2048 * Copy groups in to a credential after expanding it if required.
2049 * Truncate the list to (ngroups_max + 1) if it is too large.
2050 */
2051 void
2052 crsetgroups(struct ucred *cr, int ngrp, gid_t *groups)
2053 {
2054
2055 if (ngrp > ngroups_max + 1)
2056 ngrp = ngroups_max + 1;
2057
2058 crextend(cr, ngrp);
2059 crsetgroups_locked(cr, ngrp, groups);
2060 }
2061
2062 /*
2063 * Get login name, if available.
2064 */
2065 #ifndef _SYS_SYSPROTO_H_
2066 struct getlogin_args {
2067 char *namebuf;
2068 u_int namelen;
2069 };
2070 #endif
2071 /* ARGSUSED */
2072 int
2073 sys_getlogin(struct thread *td, struct getlogin_args *uap)
2074 {
2075 char login[MAXLOGNAME];
2076 struct proc *p = td->td_proc;
2077 size_t len;
2078
2079 if (uap->namelen > MAXLOGNAME)
2080 uap->namelen = MAXLOGNAME;
2081 PROC_LOCK(p);
2082 SESS_LOCK(p->p_session);
2083 len = strlcpy(login, p->p_session->s_login, uap->namelen) + 1;
2084 SESS_UNLOCK(p->p_session);
2085 PROC_UNLOCK(p);
2086 if (len > uap->namelen)
2087 return (ERANGE);
2088 return (copyout(login, uap->namebuf, len));
2089 }
2090
2091 /*
2092 * Set login name.
2093 */
2094 #ifndef _SYS_SYSPROTO_H_
2095 struct setlogin_args {
2096 char *namebuf;
2097 };
2098 #endif
2099 /* ARGSUSED */
2100 int
2101 sys_setlogin(struct thread *td, struct setlogin_args *uap)
2102 {
2103 struct proc *p = td->td_proc;
2104 int error;
2105 char logintmp[MAXLOGNAME];
2106
2107 CTASSERT(sizeof(p->p_session->s_login) >= sizeof(logintmp));
2108
2109 error = priv_check(td, PRIV_PROC_SETLOGIN);
2110 if (error)
2111 return (error);
2112 error = copyinstr(uap->namebuf, logintmp, sizeof(logintmp), NULL);
2113 if (error != 0) {
2114 if (error == ENAMETOOLONG)
2115 error = EINVAL;
2116 return (error);
2117 }
2118 PROC_LOCK(p);
2119 SESS_LOCK(p->p_session);
2120 strcpy(p->p_session->s_login, logintmp);
2121 SESS_UNLOCK(p->p_session);
2122 PROC_UNLOCK(p);
2123 return (0);
2124 }
2125
2126 void
2127 setsugid(struct proc *p)
2128 {
2129
2130 PROC_LOCK_ASSERT(p, MA_OWNED);
2131 p->p_flag |= P_SUGID;
2132 if (!(p->p_pfsflags & PF_ISUGID))
2133 p->p_stops = 0;
2134 }
2135
2136 /*-
2137 * Change a process's effective uid.
2138 * Side effects: newcred->cr_uid and newcred->cr_uidinfo will be modified.
2139 * References: newcred must be an exclusive credential reference for the
2140 * duration of the call.
2141 */
2142 void
2143 change_euid(struct ucred *newcred, struct uidinfo *euip)
2144 {
2145
2146 newcred->cr_uid = euip->ui_uid;
2147 uihold(euip);
2148 uifree(newcred->cr_uidinfo);
2149 newcred->cr_uidinfo = euip;
2150 }
2151
2152 /*-
2153 * Change a process's effective gid.
2154 * Side effects: newcred->cr_gid will be modified.
2155 * References: newcred must be an exclusive credential reference for the
2156 * duration of the call.
2157 */
2158 void
2159 change_egid(struct ucred *newcred, gid_t egid)
2160 {
2161
2162 newcred->cr_groups[0] = egid;
2163 }
2164
2165 /*-
2166 * Change a process's real uid.
2167 * Side effects: newcred->cr_ruid will be updated, newcred->cr_ruidinfo
2168 * will be updated, and the old and new cr_ruidinfo proc
2169 * counts will be updated.
2170 * References: newcred must be an exclusive credential reference for the
2171 * duration of the call.
2172 */
2173 void
2174 change_ruid(struct ucred *newcred, struct uidinfo *ruip)
2175 {
2176
2177 (void)chgproccnt(newcred->cr_ruidinfo, -1, 0);
2178 newcred->cr_ruid = ruip->ui_uid;
2179 uihold(ruip);
2180 uifree(newcred->cr_ruidinfo);
2181 newcred->cr_ruidinfo = ruip;
2182 (void)chgproccnt(newcred->cr_ruidinfo, 1, 0);
2183 }
2184
2185 /*-
2186 * Change a process's real gid.
2187 * Side effects: newcred->cr_rgid will be updated.
2188 * References: newcred must be an exclusive credential reference for the
2189 * duration of the call.
2190 */
2191 void
2192 change_rgid(struct ucred *newcred, gid_t rgid)
2193 {
2194
2195 newcred->cr_rgid = rgid;
2196 }
2197
2198 /*-
2199 * Change a process's saved uid.
2200 * Side effects: newcred->cr_svuid will be updated.
2201 * References: newcred must be an exclusive credential reference for the
2202 * duration of the call.
2203 */
2204 void
2205 change_svuid(struct ucred *newcred, uid_t svuid)
2206 {
2207
2208 newcred->cr_svuid = svuid;
2209 }
2210
2211 /*-
2212 * Change a process's saved gid.
2213 * Side effects: newcred->cr_svgid will be updated.
2214 * References: newcred must be an exclusive credential reference for the
2215 * duration of the call.
2216 */
2217 void
2218 change_svgid(struct ucred *newcred, gid_t svgid)
2219 {
2220
2221 newcred->cr_svgid = svgid;
2222 }
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