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/11.0/sys/kern/kern_prot.c 298819 2016-04-29 22:15:33Z pfg $");
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 td->td_retval[1] = kern_getppid(td);
108 #endif
109 return (0);
110 }
111
112 #ifndef _SYS_SYSPROTO_H_
113 struct getppid_args {
114 int dummy;
115 };
116 #endif
117 /* ARGSUSED */
118 int
119 sys_getppid(struct thread *td, struct getppid_args *uap)
120 {
121
122 td->td_retval[0] = kern_getppid(td);
123 return (0);
124 }
125
126 int
127 kern_getppid(struct thread *td)
128 {
129 struct proc *p = td->td_proc;
130 struct proc *pp;
131 int ppid;
132
133 PROC_LOCK(p);
134 if (!(p->p_flag & P_TRACED)) {
135 ppid = p->p_pptr->p_pid;
136 PROC_UNLOCK(p);
137 } else {
138 PROC_UNLOCK(p);
139 sx_slock(&proctree_lock);
140 pp = proc_realparent(p);
141 ppid = pp->p_pid;
142 sx_sunlock(&proctree_lock);
143 }
144
145 return (ppid);
146 }
147
148 /*
149 * Get process group ID; note that POSIX getpgrp takes no parameter.
150 */
151 #ifndef _SYS_SYSPROTO_H_
152 struct getpgrp_args {
153 int dummy;
154 };
155 #endif
156 int
157 sys_getpgrp(struct thread *td, struct getpgrp_args *uap)
158 {
159 struct proc *p = td->td_proc;
160
161 PROC_LOCK(p);
162 td->td_retval[0] = p->p_pgrp->pg_id;
163 PROC_UNLOCK(p);
164 return (0);
165 }
166
167 /* Get an arbitrary pid's process group id */
168 #ifndef _SYS_SYSPROTO_H_
169 struct getpgid_args {
170 pid_t pid;
171 };
172 #endif
173 int
174 sys_getpgid(struct thread *td, struct getpgid_args *uap)
175 {
176 struct proc *p;
177 int error;
178
179 if (uap->pid == 0) {
180 p = td->td_proc;
181 PROC_LOCK(p);
182 } else {
183 p = pfind(uap->pid);
184 if (p == NULL)
185 return (ESRCH);
186 error = p_cansee(td, p);
187 if (error) {
188 PROC_UNLOCK(p);
189 return (error);
190 }
191 }
192 td->td_retval[0] = p->p_pgrp->pg_id;
193 PROC_UNLOCK(p);
194 return (0);
195 }
196
197 /*
198 * Get an arbitrary pid's session id.
199 */
200 #ifndef _SYS_SYSPROTO_H_
201 struct getsid_args {
202 pid_t pid;
203 };
204 #endif
205 int
206 sys_getsid(struct thread *td, struct getsid_args *uap)
207 {
208 struct proc *p;
209 int error;
210
211 if (uap->pid == 0) {
212 p = td->td_proc;
213 PROC_LOCK(p);
214 } else {
215 p = pfind(uap->pid);
216 if (p == NULL)
217 return (ESRCH);
218 error = p_cansee(td, p);
219 if (error) {
220 PROC_UNLOCK(p);
221 return (error);
222 }
223 }
224 td->td_retval[0] = p->p_session->s_sid;
225 PROC_UNLOCK(p);
226 return (0);
227 }
228
229 #ifndef _SYS_SYSPROTO_H_
230 struct getuid_args {
231 int dummy;
232 };
233 #endif
234 /* ARGSUSED */
235 int
236 sys_getuid(struct thread *td, struct getuid_args *uap)
237 {
238
239 td->td_retval[0] = td->td_ucred->cr_ruid;
240 #if defined(COMPAT_43)
241 td->td_retval[1] = td->td_ucred->cr_uid;
242 #endif
243 return (0);
244 }
245
246 #ifndef _SYS_SYSPROTO_H_
247 struct geteuid_args {
248 int dummy;
249 };
250 #endif
251 /* ARGSUSED */
252 int
253 sys_geteuid(struct thread *td, struct geteuid_args *uap)
254 {
255
256 td->td_retval[0] = td->td_ucred->cr_uid;
257 return (0);
258 }
259
260 #ifndef _SYS_SYSPROTO_H_
261 struct getgid_args {
262 int dummy;
263 };
264 #endif
265 /* ARGSUSED */
266 int
267 sys_getgid(struct thread *td, struct getgid_args *uap)
268 {
269
270 td->td_retval[0] = td->td_ucred->cr_rgid;
271 #if defined(COMPAT_43)
272 td->td_retval[1] = td->td_ucred->cr_groups[0];
273 #endif
274 return (0);
275 }
276
277 /*
278 * Get effective group ID. The "egid" is groups[0], and could be obtained
279 * via getgroups. This syscall exists because it is somewhat painful to do
280 * correctly in a library function.
281 */
282 #ifndef _SYS_SYSPROTO_H_
283 struct getegid_args {
284 int dummy;
285 };
286 #endif
287 /* ARGSUSED */
288 int
289 sys_getegid(struct thread *td, struct getegid_args *uap)
290 {
291
292 td->td_retval[0] = td->td_ucred->cr_groups[0];
293 return (0);
294 }
295
296 #ifndef _SYS_SYSPROTO_H_
297 struct getgroups_args {
298 u_int gidsetsize;
299 gid_t *gidset;
300 };
301 #endif
302 int
303 sys_getgroups(struct thread *td, register struct getgroups_args *uap)
304 {
305 struct ucred *cred;
306 u_int ngrp;
307 int error;
308
309 cred = td->td_ucred;
310 ngrp = cred->cr_ngroups;
311
312 if (uap->gidsetsize == 0) {
313 error = 0;
314 goto out;
315 }
316 if (uap->gidsetsize < ngrp)
317 return (EINVAL);
318
319 error = copyout(cred->cr_groups, uap->gidset, ngrp * sizeof(gid_t));
320 out:
321 td->td_retval[0] = ngrp;
322 return (error);
323 }
324
325 #ifndef _SYS_SYSPROTO_H_
326 struct setsid_args {
327 int dummy;
328 };
329 #endif
330 /* ARGSUSED */
331 int
332 sys_setsid(register struct thread *td, struct setsid_args *uap)
333 {
334 struct pgrp *pgrp;
335 int error;
336 struct proc *p = td->td_proc;
337 struct pgrp *newpgrp;
338 struct session *newsess;
339
340 error = 0;
341 pgrp = NULL;
342
343 newpgrp = malloc(sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
344 newsess = malloc(sizeof(struct session), M_SESSION, M_WAITOK | M_ZERO);
345
346 sx_xlock(&proctree_lock);
347
348 if (p->p_pgid == p->p_pid || (pgrp = pgfind(p->p_pid)) != NULL) {
349 if (pgrp != NULL)
350 PGRP_UNLOCK(pgrp);
351 error = EPERM;
352 } else {
353 (void)enterpgrp(p, p->p_pid, newpgrp, newsess);
354 td->td_retval[0] = p->p_pid;
355 newpgrp = NULL;
356 newsess = NULL;
357 }
358
359 sx_xunlock(&proctree_lock);
360
361 if (newpgrp != NULL)
362 free(newpgrp, M_PGRP);
363 if (newsess != NULL)
364 free(newsess, M_SESSION);
365
366 return (error);
367 }
368
369 /*
370 * set process group (setpgid/old setpgrp)
371 *
372 * caller does setpgid(targpid, targpgid)
373 *
374 * pid must be caller or child of caller (ESRCH)
375 * if a child
376 * pid must be in same session (EPERM)
377 * pid can't have done an exec (EACCES)
378 * if pgid != pid
379 * there must exist some pid in same session having pgid (EPERM)
380 * pid must not be session leader (EPERM)
381 */
382 #ifndef _SYS_SYSPROTO_H_
383 struct setpgid_args {
384 int pid; /* target process id */
385 int pgid; /* target pgrp id */
386 };
387 #endif
388 /* ARGSUSED */
389 int
390 sys_setpgid(struct thread *td, register struct setpgid_args *uap)
391 {
392 struct proc *curp = td->td_proc;
393 register struct proc *targp; /* target process */
394 register struct pgrp *pgrp; /* target pgrp */
395 int error;
396 struct pgrp *newpgrp;
397
398 if (uap->pgid < 0)
399 return (EINVAL);
400
401 error = 0;
402
403 newpgrp = malloc(sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
404
405 sx_xlock(&proctree_lock);
406 if (uap->pid != 0 && uap->pid != curp->p_pid) {
407 if ((targp = pfind(uap->pid)) == NULL) {
408 error = ESRCH;
409 goto done;
410 }
411 if (!inferior(targp)) {
412 PROC_UNLOCK(targp);
413 error = ESRCH;
414 goto done;
415 }
416 if ((error = p_cansee(td, targp))) {
417 PROC_UNLOCK(targp);
418 goto done;
419 }
420 if (targp->p_pgrp == NULL ||
421 targp->p_session != curp->p_session) {
422 PROC_UNLOCK(targp);
423 error = EPERM;
424 goto done;
425 }
426 if (targp->p_flag & P_EXEC) {
427 PROC_UNLOCK(targp);
428 error = EACCES;
429 goto done;
430 }
431 PROC_UNLOCK(targp);
432 } else
433 targp = curp;
434 if (SESS_LEADER(targp)) {
435 error = EPERM;
436 goto done;
437 }
438 if (uap->pgid == 0)
439 uap->pgid = targp->p_pid;
440 if ((pgrp = pgfind(uap->pgid)) == NULL) {
441 if (uap->pgid == targp->p_pid) {
442 error = enterpgrp(targp, uap->pgid, newpgrp,
443 NULL);
444 if (error == 0)
445 newpgrp = NULL;
446 } else
447 error = EPERM;
448 } else {
449 if (pgrp == targp->p_pgrp) {
450 PGRP_UNLOCK(pgrp);
451 goto done;
452 }
453 if (pgrp->pg_id != targp->p_pid &&
454 pgrp->pg_session != curp->p_session) {
455 PGRP_UNLOCK(pgrp);
456 error = EPERM;
457 goto done;
458 }
459 PGRP_UNLOCK(pgrp);
460 error = enterthispgrp(targp, pgrp);
461 }
462 done:
463 sx_xunlock(&proctree_lock);
464 KASSERT((error == 0) || (newpgrp != NULL),
465 ("setpgid failed and newpgrp is NULL"));
466 if (newpgrp != NULL)
467 free(newpgrp, M_PGRP);
468 return (error);
469 }
470
471 /*
472 * Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD
473 * compatible. It says that setting the uid/gid to euid/egid is a special
474 * case of "appropriate privilege". Once the rules are expanded out, this
475 * basically means that setuid(nnn) sets all three id's, in all permitted
476 * cases unless _POSIX_SAVED_IDS is enabled. In that case, setuid(getuid())
477 * does not set the saved id - this is dangerous for traditional BSD
478 * programs. For this reason, we *really* do not want to set
479 * _POSIX_SAVED_IDS and do not want to clear POSIX_APPENDIX_B_4_2_2.
480 */
481 #define POSIX_APPENDIX_B_4_2_2
482
483 #ifndef _SYS_SYSPROTO_H_
484 struct setuid_args {
485 uid_t uid;
486 };
487 #endif
488 /* ARGSUSED */
489 int
490 sys_setuid(struct thread *td, struct setuid_args *uap)
491 {
492 struct proc *p = td->td_proc;
493 struct ucred *newcred, *oldcred;
494 uid_t uid;
495 struct uidinfo *uip;
496 int error;
497
498 uid = uap->uid;
499 AUDIT_ARG_UID(uid);
500 newcred = crget();
501 uip = uifind(uid);
502 PROC_LOCK(p);
503 /*
504 * Copy credentials so other references do not see our changes.
505 */
506 oldcred = crcopysafe(p, newcred);
507
508 #ifdef MAC
509 error = mac_cred_check_setuid(oldcred, uid);
510 if (error)
511 goto fail;
512 #endif
513
514 /*
515 * See if we have "permission" by POSIX 1003.1 rules.
516 *
517 * Note that setuid(geteuid()) is a special case of
518 * "appropriate privileges" in appendix B.4.2.2. We need
519 * to use this clause to be compatible with traditional BSD
520 * semantics. Basically, it means that "setuid(xx)" sets all
521 * three id's (assuming you have privs).
522 *
523 * Notes on the logic. We do things in three steps.
524 * 1: We determine if the euid is going to change, and do EPERM
525 * right away. We unconditionally change the euid later if this
526 * test is satisfied, simplifying that part of the logic.
527 * 2: We determine if the real and/or saved uids are going to
528 * change. Determined by compile options.
529 * 3: Change euid last. (after tests in #2 for "appropriate privs")
530 */
531 if (uid != oldcred->cr_ruid && /* allow setuid(getuid()) */
532 #ifdef _POSIX_SAVED_IDS
533 uid != oldcred->cr_svuid && /* allow setuid(saved gid) */
534 #endif
535 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
536 uid != oldcred->cr_uid && /* allow setuid(geteuid()) */
537 #endif
538 (error = priv_check_cred(oldcred, PRIV_CRED_SETUID, 0)) != 0)
539 goto fail;
540
541 #ifdef _POSIX_SAVED_IDS
542 /*
543 * Do we have "appropriate privileges" (are we root or uid == euid)
544 * If so, we are changing the real uid and/or saved uid.
545 */
546 if (
547 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use the clause from B.4.2.2 */
548 uid == oldcred->cr_uid ||
549 #endif
550 /* We are using privs. */
551 priv_check_cred(oldcred, PRIV_CRED_SETUID, 0) == 0)
552 #endif
553 {
554 /*
555 * Set the real uid and transfer proc count to new user.
556 */
557 if (uid != oldcred->cr_ruid) {
558 change_ruid(newcred, uip);
559 setsugid(p);
560 }
561 /*
562 * Set saved uid
563 *
564 * XXX always set saved uid even if not _POSIX_SAVED_IDS, as
565 * the security of seteuid() depends on it. B.4.2.2 says it
566 * is important that we should do this.
567 */
568 if (uid != oldcred->cr_svuid) {
569 change_svuid(newcred, uid);
570 setsugid(p);
571 }
572 }
573
574 /*
575 * In all permitted cases, we are changing the euid.
576 */
577 if (uid != oldcred->cr_uid) {
578 change_euid(newcred, uip);
579 setsugid(p);
580 }
581 proc_set_cred(p, newcred);
582 PROC_UNLOCK(p);
583 #ifdef RACCT
584 racct_proc_ucred_changed(p, oldcred, newcred);
585 #endif
586 uifree(uip);
587 crfree(oldcred);
588 return (0);
589
590 fail:
591 PROC_UNLOCK(p);
592 uifree(uip);
593 crfree(newcred);
594 return (error);
595 }
596
597 #ifndef _SYS_SYSPROTO_H_
598 struct seteuid_args {
599 uid_t euid;
600 };
601 #endif
602 /* ARGSUSED */
603 int
604 sys_seteuid(struct thread *td, struct seteuid_args *uap)
605 {
606 struct proc *p = td->td_proc;
607 struct ucred *newcred, *oldcred;
608 uid_t euid;
609 struct uidinfo *euip;
610 int error;
611
612 euid = uap->euid;
613 AUDIT_ARG_EUID(euid);
614 newcred = crget();
615 euip = uifind(euid);
616 PROC_LOCK(p);
617 /*
618 * Copy credentials so other references do not see our changes.
619 */
620 oldcred = crcopysafe(p, newcred);
621
622 #ifdef MAC
623 error = mac_cred_check_seteuid(oldcred, euid);
624 if (error)
625 goto fail;
626 #endif
627
628 if (euid != oldcred->cr_ruid && /* allow seteuid(getuid()) */
629 euid != oldcred->cr_svuid && /* allow seteuid(saved uid) */
630 (error = priv_check_cred(oldcred, PRIV_CRED_SETEUID, 0)) != 0)
631 goto fail;
632
633 /*
634 * Everything's okay, do it.
635 */
636 if (oldcred->cr_uid != euid) {
637 change_euid(newcred, euip);
638 setsugid(p);
639 }
640 proc_set_cred(p, newcred);
641 PROC_UNLOCK(p);
642 uifree(euip);
643 crfree(oldcred);
644 return (0);
645
646 fail:
647 PROC_UNLOCK(p);
648 uifree(euip);
649 crfree(newcred);
650 return (error);
651 }
652
653 #ifndef _SYS_SYSPROTO_H_
654 struct setgid_args {
655 gid_t gid;
656 };
657 #endif
658 /* ARGSUSED */
659 int
660 sys_setgid(struct thread *td, struct setgid_args *uap)
661 {
662 struct proc *p = td->td_proc;
663 struct ucred *newcred, *oldcred;
664 gid_t gid;
665 int error;
666
667 gid = uap->gid;
668 AUDIT_ARG_GID(gid);
669 newcred = crget();
670 PROC_LOCK(p);
671 oldcred = crcopysafe(p, newcred);
672
673 #ifdef MAC
674 error = mac_cred_check_setgid(oldcred, gid);
675 if (error)
676 goto fail;
677 #endif
678
679 /*
680 * See if we have "permission" by POSIX 1003.1 rules.
681 *
682 * Note that setgid(getegid()) is a special case of
683 * "appropriate privileges" in appendix B.4.2.2. We need
684 * to use this clause to be compatible with traditional BSD
685 * semantics. Basically, it means that "setgid(xx)" sets all
686 * three id's (assuming you have privs).
687 *
688 * For notes on the logic here, see setuid() above.
689 */
690 if (gid != oldcred->cr_rgid && /* allow setgid(getgid()) */
691 #ifdef _POSIX_SAVED_IDS
692 gid != oldcred->cr_svgid && /* allow setgid(saved gid) */
693 #endif
694 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
695 gid != oldcred->cr_groups[0] && /* allow setgid(getegid()) */
696 #endif
697 (error = priv_check_cred(oldcred, PRIV_CRED_SETGID, 0)) != 0)
698 goto fail;
699
700 #ifdef _POSIX_SAVED_IDS
701 /*
702 * Do we have "appropriate privileges" (are we root or gid == egid)
703 * If so, we are changing the real uid and saved gid.
704 */
705 if (
706 #ifdef POSIX_APPENDIX_B_4_2_2 /* use the clause from B.4.2.2 */
707 gid == oldcred->cr_groups[0] ||
708 #endif
709 /* We are using privs. */
710 priv_check_cred(oldcred, PRIV_CRED_SETGID, 0) == 0)
711 #endif
712 {
713 /*
714 * Set real gid
715 */
716 if (oldcred->cr_rgid != gid) {
717 change_rgid(newcred, gid);
718 setsugid(p);
719 }
720 /*
721 * Set saved gid
722 *
723 * XXX always set saved gid even if not _POSIX_SAVED_IDS, as
724 * the security of setegid() depends on it. B.4.2.2 says it
725 * is important that we should do this.
726 */
727 if (oldcred->cr_svgid != gid) {
728 change_svgid(newcred, gid);
729 setsugid(p);
730 }
731 }
732 /*
733 * In all cases permitted cases, we are changing the egid.
734 * Copy credentials so other references do not see our changes.
735 */
736 if (oldcred->cr_groups[0] != gid) {
737 change_egid(newcred, gid);
738 setsugid(p);
739 }
740 proc_set_cred(p, newcred);
741 PROC_UNLOCK(p);
742 crfree(oldcred);
743 return (0);
744
745 fail:
746 PROC_UNLOCK(p);
747 crfree(newcred);
748 return (error);
749 }
750
751 #ifndef _SYS_SYSPROTO_H_
752 struct setegid_args {
753 gid_t egid;
754 };
755 #endif
756 /* ARGSUSED */
757 int
758 sys_setegid(struct thread *td, struct setegid_args *uap)
759 {
760 struct proc *p = td->td_proc;
761 struct ucred *newcred, *oldcred;
762 gid_t egid;
763 int error;
764
765 egid = uap->egid;
766 AUDIT_ARG_EGID(egid);
767 newcred = crget();
768 PROC_LOCK(p);
769 oldcred = crcopysafe(p, newcred);
770
771 #ifdef MAC
772 error = mac_cred_check_setegid(oldcred, egid);
773 if (error)
774 goto fail;
775 #endif
776
777 if (egid != oldcred->cr_rgid && /* allow setegid(getgid()) */
778 egid != oldcred->cr_svgid && /* allow setegid(saved gid) */
779 (error = priv_check_cred(oldcred, PRIV_CRED_SETEGID, 0)) != 0)
780 goto fail;
781
782 if (oldcred->cr_groups[0] != egid) {
783 change_egid(newcred, egid);
784 setsugid(p);
785 }
786 proc_set_cred(p, newcred);
787 PROC_UNLOCK(p);
788 crfree(oldcred);
789 return (0);
790
791 fail:
792 PROC_UNLOCK(p);
793 crfree(newcred);
794 return (error);
795 }
796
797 #ifndef _SYS_SYSPROTO_H_
798 struct setgroups_args {
799 u_int gidsetsize;
800 gid_t *gidset;
801 };
802 #endif
803 /* ARGSUSED */
804 int
805 sys_setgroups(struct thread *td, struct setgroups_args *uap)
806 {
807 gid_t smallgroups[XU_NGROUPS];
808 gid_t *groups;
809 u_int gidsetsize;
810 int error;
811
812 gidsetsize = uap->gidsetsize;
813 if (gidsetsize > ngroups_max + 1)
814 return (EINVAL);
815
816 if (gidsetsize > XU_NGROUPS)
817 groups = malloc(gidsetsize * sizeof(gid_t), M_TEMP, M_WAITOK);
818 else
819 groups = smallgroups;
820
821 error = copyin(uap->gidset, groups, gidsetsize * sizeof(gid_t));
822 if (error == 0)
823 error = kern_setgroups(td, gidsetsize, groups);
824
825 if (gidsetsize > XU_NGROUPS)
826 free(groups, M_TEMP);
827 return (error);
828 }
829
830 int
831 kern_setgroups(struct thread *td, u_int ngrp, gid_t *groups)
832 {
833 struct proc *p = td->td_proc;
834 struct ucred *newcred, *oldcred;
835 int error;
836
837 MPASS(ngrp <= ngroups_max + 1);
838 AUDIT_ARG_GROUPSET(groups, ngrp);
839 newcred = crget();
840 crextend(newcred, ngrp);
841 PROC_LOCK(p);
842 oldcred = crcopysafe(p, newcred);
843
844 #ifdef MAC
845 error = mac_cred_check_setgroups(oldcred, ngrp, groups);
846 if (error)
847 goto fail;
848 #endif
849
850 error = priv_check_cred(oldcred, PRIV_CRED_SETGROUPS, 0);
851 if (error)
852 goto fail;
853
854 if (ngrp == 0) {
855 /*
856 * setgroups(0, NULL) is a legitimate way of clearing the
857 * groups vector on non-BSD systems (which generally do not
858 * have the egid in the groups[0]). We risk security holes
859 * when running non-BSD software if we do not do the same.
860 */
861 newcred->cr_ngroups = 1;
862 } else {
863 crsetgroups_locked(newcred, ngrp, groups);
864 }
865 setsugid(p);
866 proc_set_cred(p, newcred);
867 PROC_UNLOCK(p);
868 crfree(oldcred);
869 return (0);
870
871 fail:
872 PROC_UNLOCK(p);
873 crfree(newcred);
874 return (error);
875 }
876
877 #ifndef _SYS_SYSPROTO_H_
878 struct setreuid_args {
879 uid_t ruid;
880 uid_t euid;
881 };
882 #endif
883 /* ARGSUSED */
884 int
885 sys_setreuid(register struct thread *td, struct setreuid_args *uap)
886 {
887 struct proc *p = td->td_proc;
888 struct ucred *newcred, *oldcred;
889 uid_t euid, ruid;
890 struct uidinfo *euip, *ruip;
891 int error;
892
893 euid = uap->euid;
894 ruid = uap->ruid;
895 AUDIT_ARG_EUID(euid);
896 AUDIT_ARG_RUID(ruid);
897 newcred = crget();
898 euip = uifind(euid);
899 ruip = uifind(ruid);
900 PROC_LOCK(p);
901 oldcred = crcopysafe(p, newcred);
902
903 #ifdef MAC
904 error = mac_cred_check_setreuid(oldcred, ruid, euid);
905 if (error)
906 goto fail;
907 #endif
908
909 if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
910 ruid != oldcred->cr_svuid) ||
911 (euid != (uid_t)-1 && euid != oldcred->cr_uid &&
912 euid != oldcred->cr_ruid && euid != oldcred->cr_svuid)) &&
913 (error = priv_check_cred(oldcred, PRIV_CRED_SETREUID, 0)) != 0)
914 goto fail;
915
916 if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
917 change_euid(newcred, euip);
918 setsugid(p);
919 }
920 if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
921 change_ruid(newcred, ruip);
922 setsugid(p);
923 }
924 if ((ruid != (uid_t)-1 || newcred->cr_uid != newcred->cr_ruid) &&
925 newcred->cr_svuid != newcred->cr_uid) {
926 change_svuid(newcred, newcred->cr_uid);
927 setsugid(p);
928 }
929 proc_set_cred(p, newcred);
930 PROC_UNLOCK(p);
931 #ifdef RACCT
932 racct_proc_ucred_changed(p, oldcred, newcred);
933 #endif
934 uifree(ruip);
935 uifree(euip);
936 crfree(oldcred);
937 return (0);
938
939 fail:
940 PROC_UNLOCK(p);
941 uifree(ruip);
942 uifree(euip);
943 crfree(newcred);
944 return (error);
945 }
946
947 #ifndef _SYS_SYSPROTO_H_
948 struct setregid_args {
949 gid_t rgid;
950 gid_t egid;
951 };
952 #endif
953 /* ARGSUSED */
954 int
955 sys_setregid(register struct thread *td, struct setregid_args *uap)
956 {
957 struct proc *p = td->td_proc;
958 struct ucred *newcred, *oldcred;
959 gid_t egid, rgid;
960 int error;
961
962 egid = uap->egid;
963 rgid = uap->rgid;
964 AUDIT_ARG_EGID(egid);
965 AUDIT_ARG_RGID(rgid);
966 newcred = crget();
967 PROC_LOCK(p);
968 oldcred = crcopysafe(p, newcred);
969
970 #ifdef MAC
971 error = mac_cred_check_setregid(oldcred, rgid, egid);
972 if (error)
973 goto fail;
974 #endif
975
976 if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
977 rgid != oldcred->cr_svgid) ||
978 (egid != (gid_t)-1 && egid != oldcred->cr_groups[0] &&
979 egid != oldcred->cr_rgid && egid != oldcred->cr_svgid)) &&
980 (error = priv_check_cred(oldcred, PRIV_CRED_SETREGID, 0)) != 0)
981 goto fail;
982
983 if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
984 change_egid(newcred, egid);
985 setsugid(p);
986 }
987 if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
988 change_rgid(newcred, rgid);
989 setsugid(p);
990 }
991 if ((rgid != (gid_t)-1 || newcred->cr_groups[0] != newcred->cr_rgid) &&
992 newcred->cr_svgid != newcred->cr_groups[0]) {
993 change_svgid(newcred, newcred->cr_groups[0]);
994 setsugid(p);
995 }
996 proc_set_cred(p, newcred);
997 PROC_UNLOCK(p);
998 crfree(oldcred);
999 return (0);
1000
1001 fail:
1002 PROC_UNLOCK(p);
1003 crfree(newcred);
1004 return (error);
1005 }
1006
1007 /*
1008 * setresuid(ruid, euid, suid) is like setreuid except control over the saved
1009 * uid is explicit.
1010 */
1011 #ifndef _SYS_SYSPROTO_H_
1012 struct setresuid_args {
1013 uid_t ruid;
1014 uid_t euid;
1015 uid_t suid;
1016 };
1017 #endif
1018 /* ARGSUSED */
1019 int
1020 sys_setresuid(register struct thread *td, struct setresuid_args *uap)
1021 {
1022 struct proc *p = td->td_proc;
1023 struct ucred *newcred, *oldcred;
1024 uid_t euid, ruid, suid;
1025 struct uidinfo *euip, *ruip;
1026 int error;
1027
1028 euid = uap->euid;
1029 ruid = uap->ruid;
1030 suid = uap->suid;
1031 AUDIT_ARG_EUID(euid);
1032 AUDIT_ARG_RUID(ruid);
1033 AUDIT_ARG_SUID(suid);
1034 newcred = crget();
1035 euip = uifind(euid);
1036 ruip = uifind(ruid);
1037 PROC_LOCK(p);
1038 oldcred = crcopysafe(p, newcred);
1039
1040 #ifdef MAC
1041 error = mac_cred_check_setresuid(oldcred, ruid, euid, suid);
1042 if (error)
1043 goto fail;
1044 #endif
1045
1046 if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
1047 ruid != oldcred->cr_svuid &&
1048 ruid != oldcred->cr_uid) ||
1049 (euid != (uid_t)-1 && euid != oldcred->cr_ruid &&
1050 euid != oldcred->cr_svuid &&
1051 euid != oldcred->cr_uid) ||
1052 (suid != (uid_t)-1 && suid != oldcred->cr_ruid &&
1053 suid != oldcred->cr_svuid &&
1054 suid != oldcred->cr_uid)) &&
1055 (error = priv_check_cred(oldcred, PRIV_CRED_SETRESUID, 0)) != 0)
1056 goto fail;
1057
1058 if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
1059 change_euid(newcred, euip);
1060 setsugid(p);
1061 }
1062 if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
1063 change_ruid(newcred, ruip);
1064 setsugid(p);
1065 }
1066 if (suid != (uid_t)-1 && oldcred->cr_svuid != suid) {
1067 change_svuid(newcred, suid);
1068 setsugid(p);
1069 }
1070 proc_set_cred(p, newcred);
1071 PROC_UNLOCK(p);
1072 #ifdef RACCT
1073 racct_proc_ucred_changed(p, oldcred, newcred);
1074 #endif
1075 uifree(ruip);
1076 uifree(euip);
1077 crfree(oldcred);
1078 return (0);
1079
1080 fail:
1081 PROC_UNLOCK(p);
1082 uifree(ruip);
1083 uifree(euip);
1084 crfree(newcred);
1085 return (error);
1086
1087 }
1088
1089 /*
1090 * setresgid(rgid, egid, sgid) is like setregid except control over the saved
1091 * gid is explicit.
1092 */
1093 #ifndef _SYS_SYSPROTO_H_
1094 struct setresgid_args {
1095 gid_t rgid;
1096 gid_t egid;
1097 gid_t sgid;
1098 };
1099 #endif
1100 /* ARGSUSED */
1101 int
1102 sys_setresgid(register struct thread *td, struct setresgid_args *uap)
1103 {
1104 struct proc *p = td->td_proc;
1105 struct ucred *newcred, *oldcred;
1106 gid_t egid, rgid, sgid;
1107 int error;
1108
1109 egid = uap->egid;
1110 rgid = uap->rgid;
1111 sgid = uap->sgid;
1112 AUDIT_ARG_EGID(egid);
1113 AUDIT_ARG_RGID(rgid);
1114 AUDIT_ARG_SGID(sgid);
1115 newcred = crget();
1116 PROC_LOCK(p);
1117 oldcred = crcopysafe(p, newcred);
1118
1119 #ifdef MAC
1120 error = mac_cred_check_setresgid(oldcred, rgid, egid, sgid);
1121 if (error)
1122 goto fail;
1123 #endif
1124
1125 if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
1126 rgid != oldcred->cr_svgid &&
1127 rgid != oldcred->cr_groups[0]) ||
1128 (egid != (gid_t)-1 && egid != oldcred->cr_rgid &&
1129 egid != oldcred->cr_svgid &&
1130 egid != oldcred->cr_groups[0]) ||
1131 (sgid != (gid_t)-1 && sgid != oldcred->cr_rgid &&
1132 sgid != oldcred->cr_svgid &&
1133 sgid != oldcred->cr_groups[0])) &&
1134 (error = priv_check_cred(oldcred, PRIV_CRED_SETRESGID, 0)) != 0)
1135 goto fail;
1136
1137 if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
1138 change_egid(newcred, egid);
1139 setsugid(p);
1140 }
1141 if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
1142 change_rgid(newcred, rgid);
1143 setsugid(p);
1144 }
1145 if (sgid != (gid_t)-1 && oldcred->cr_svgid != sgid) {
1146 change_svgid(newcred, sgid);
1147 setsugid(p);
1148 }
1149 proc_set_cred(p, newcred);
1150 PROC_UNLOCK(p);
1151 crfree(oldcred);
1152 return (0);
1153
1154 fail:
1155 PROC_UNLOCK(p);
1156 crfree(newcred);
1157 return (error);
1158 }
1159
1160 #ifndef _SYS_SYSPROTO_H_
1161 struct getresuid_args {
1162 uid_t *ruid;
1163 uid_t *euid;
1164 uid_t *suid;
1165 };
1166 #endif
1167 /* ARGSUSED */
1168 int
1169 sys_getresuid(register struct thread *td, struct getresuid_args *uap)
1170 {
1171 struct ucred *cred;
1172 int error1 = 0, error2 = 0, error3 = 0;
1173
1174 cred = td->td_ucred;
1175 if (uap->ruid)
1176 error1 = copyout(&cred->cr_ruid,
1177 uap->ruid, sizeof(cred->cr_ruid));
1178 if (uap->euid)
1179 error2 = copyout(&cred->cr_uid,
1180 uap->euid, sizeof(cred->cr_uid));
1181 if (uap->suid)
1182 error3 = copyout(&cred->cr_svuid,
1183 uap->suid, sizeof(cred->cr_svuid));
1184 return (error1 ? error1 : error2 ? error2 : error3);
1185 }
1186
1187 #ifndef _SYS_SYSPROTO_H_
1188 struct getresgid_args {
1189 gid_t *rgid;
1190 gid_t *egid;
1191 gid_t *sgid;
1192 };
1193 #endif
1194 /* ARGSUSED */
1195 int
1196 sys_getresgid(register struct thread *td, struct getresgid_args *uap)
1197 {
1198 struct ucred *cred;
1199 int error1 = 0, error2 = 0, error3 = 0;
1200
1201 cred = td->td_ucred;
1202 if (uap->rgid)
1203 error1 = copyout(&cred->cr_rgid,
1204 uap->rgid, sizeof(cred->cr_rgid));
1205 if (uap->egid)
1206 error2 = copyout(&cred->cr_groups[0],
1207 uap->egid, sizeof(cred->cr_groups[0]));
1208 if (uap->sgid)
1209 error3 = copyout(&cred->cr_svgid,
1210 uap->sgid, sizeof(cred->cr_svgid));
1211 return (error1 ? error1 : error2 ? error2 : error3);
1212 }
1213
1214 #ifndef _SYS_SYSPROTO_H_
1215 struct issetugid_args {
1216 int dummy;
1217 };
1218 #endif
1219 /* ARGSUSED */
1220 int
1221 sys_issetugid(register struct thread *td, struct issetugid_args *uap)
1222 {
1223 struct proc *p = td->td_proc;
1224
1225 /*
1226 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
1227 * we use P_SUGID because we consider changing the owners as
1228 * "tainting" as well.
1229 * This is significant for procs that start as root and "become"
1230 * a user without an exec - programs cannot know *everything*
1231 * that libc *might* have put in their data segment.
1232 */
1233 PROC_LOCK(p);
1234 td->td_retval[0] = (p->p_flag & P_SUGID) ? 1 : 0;
1235 PROC_UNLOCK(p);
1236 return (0);
1237 }
1238
1239 int
1240 sys___setugid(struct thread *td, struct __setugid_args *uap)
1241 {
1242 #ifdef REGRESSION
1243 struct proc *p;
1244
1245 p = td->td_proc;
1246 switch (uap->flag) {
1247 case 0:
1248 PROC_LOCK(p);
1249 p->p_flag &= ~P_SUGID;
1250 PROC_UNLOCK(p);
1251 return (0);
1252 case 1:
1253 PROC_LOCK(p);
1254 p->p_flag |= P_SUGID;
1255 PROC_UNLOCK(p);
1256 return (0);
1257 default:
1258 return (EINVAL);
1259 }
1260 #else /* !REGRESSION */
1261
1262 return (ENOSYS);
1263 #endif /* REGRESSION */
1264 }
1265
1266 /*
1267 * Check if gid is a member of the group set.
1268 */
1269 int
1270 groupmember(gid_t gid, struct ucred *cred)
1271 {
1272 int l;
1273 int h;
1274 int m;
1275
1276 if (cred->cr_groups[0] == gid)
1277 return(1);
1278
1279 /*
1280 * If gid was not our primary group, perform a binary search
1281 * of the supplemental groups. This is possible because we
1282 * sort the groups in crsetgroups().
1283 */
1284 l = 1;
1285 h = cred->cr_ngroups;
1286 while (l < h) {
1287 m = l + ((h - l) / 2);
1288 if (cred->cr_groups[m] < gid)
1289 l = m + 1;
1290 else
1291 h = m;
1292 }
1293 if ((l < cred->cr_ngroups) && (cred->cr_groups[l] == gid))
1294 return (1);
1295
1296 return (0);
1297 }
1298
1299 /*
1300 * Test the active securelevel against a given level. securelevel_gt()
1301 * implements (securelevel > level). securelevel_ge() implements
1302 * (securelevel >= level). Note that the logic is inverted -- these
1303 * functions return EPERM on "success" and 0 on "failure".
1304 *
1305 * Due to care taken when setting the securelevel, we know that no jail will
1306 * be less secure that its parent (or the physical system), so it is sufficient
1307 * to test the current jail only.
1308 *
1309 * XXXRW: Possibly since this has to do with privilege, it should move to
1310 * kern_priv.c.
1311 */
1312 int
1313 securelevel_gt(struct ucred *cr, int level)
1314 {
1315
1316 return (cr->cr_prison->pr_securelevel > level ? EPERM : 0);
1317 }
1318
1319 int
1320 securelevel_ge(struct ucred *cr, int level)
1321 {
1322
1323 return (cr->cr_prison->pr_securelevel >= level ? EPERM : 0);
1324 }
1325
1326 /*
1327 * 'see_other_uids' determines whether or not visibility of processes
1328 * and sockets with credentials holding different real uids is possible
1329 * using a variety of system MIBs.
1330 * XXX: data declarations should be together near the beginning of the file.
1331 */
1332 static int see_other_uids = 1;
1333 SYSCTL_INT(_security_bsd, OID_AUTO, see_other_uids, CTLFLAG_RW,
1334 &see_other_uids, 0,
1335 "Unprivileged processes may see subjects/objects with different real uid");
1336
1337 /*-
1338 * Determine if u1 "can see" the subject specified by u2, according to the
1339 * 'see_other_uids' policy.
1340 * Returns: 0 for permitted, ESRCH otherwise
1341 * Locks: none
1342 * References: *u1 and *u2 must not change during the call
1343 * u1 may equal u2, in which case only one reference is required
1344 */
1345 static int
1346 cr_seeotheruids(struct ucred *u1, struct ucred *u2)
1347 {
1348
1349 if (!see_other_uids && u1->cr_ruid != u2->cr_ruid) {
1350 if (priv_check_cred(u1, PRIV_SEEOTHERUIDS, 0) != 0)
1351 return (ESRCH);
1352 }
1353 return (0);
1354 }
1355
1356 /*
1357 * 'see_other_gids' determines whether or not visibility of processes
1358 * and sockets with credentials holding different real gids is possible
1359 * using a variety of system MIBs.
1360 * XXX: data declarations should be together near the beginning of the file.
1361 */
1362 static int see_other_gids = 1;
1363 SYSCTL_INT(_security_bsd, OID_AUTO, see_other_gids, CTLFLAG_RW,
1364 &see_other_gids, 0,
1365 "Unprivileged processes may see subjects/objects with different real gid");
1366
1367 /*
1368 * Determine if u1 can "see" the subject specified by u2, according to the
1369 * 'see_other_gids' policy.
1370 * Returns: 0 for permitted, ESRCH otherwise
1371 * Locks: none
1372 * References: *u1 and *u2 must not change during the call
1373 * u1 may equal u2, in which case only one reference is required
1374 */
1375 static int
1376 cr_seeothergids(struct ucred *u1, struct ucred *u2)
1377 {
1378 int i, match;
1379
1380 if (!see_other_gids) {
1381 match = 0;
1382 for (i = 0; i < u1->cr_ngroups; i++) {
1383 if (groupmember(u1->cr_groups[i], u2))
1384 match = 1;
1385 if (match)
1386 break;
1387 }
1388 if (!match) {
1389 if (priv_check_cred(u1, PRIV_SEEOTHERGIDS, 0) != 0)
1390 return (ESRCH);
1391 }
1392 }
1393 return (0);
1394 }
1395
1396 /*-
1397 * Determine if u1 "can see" the subject specified by u2.
1398 * Returns: 0 for permitted, an errno value otherwise
1399 * Locks: none
1400 * References: *u1 and *u2 must not change during the call
1401 * u1 may equal u2, in which case only one reference is required
1402 */
1403 int
1404 cr_cansee(struct ucred *u1, struct ucred *u2)
1405 {
1406 int error;
1407
1408 if ((error = prison_check(u1, u2)))
1409 return (error);
1410 #ifdef MAC
1411 if ((error = mac_cred_check_visible(u1, u2)))
1412 return (error);
1413 #endif
1414 if ((error = cr_seeotheruids(u1, u2)))
1415 return (error);
1416 if ((error = cr_seeothergids(u1, u2)))
1417 return (error);
1418 return (0);
1419 }
1420
1421 /*-
1422 * Determine if td "can see" the subject specified by p.
1423 * Returns: 0 for permitted, an errno value otherwise
1424 * Locks: Sufficient locks to protect p->p_ucred must be held. td really
1425 * should be curthread.
1426 * References: td and p must be valid for the lifetime of the call
1427 */
1428 int
1429 p_cansee(struct thread *td, struct proc *p)
1430 {
1431
1432 /* Wrap cr_cansee() for all functionality. */
1433 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1434 PROC_LOCK_ASSERT(p, MA_OWNED);
1435 return (cr_cansee(td->td_ucred, p->p_ucred));
1436 }
1437
1438 /*
1439 * 'conservative_signals' prevents the delivery of a broad class of
1440 * signals by unprivileged processes to processes that have changed their
1441 * credentials since the last invocation of execve(). This can prevent
1442 * the leakage of cached information or retained privileges as a result
1443 * of a common class of signal-related vulnerabilities. However, this
1444 * may interfere with some applications that expect to be able to
1445 * deliver these signals to peer processes after having given up
1446 * privilege.
1447 */
1448 static int conservative_signals = 1;
1449 SYSCTL_INT(_security_bsd, OID_AUTO, conservative_signals, CTLFLAG_RW,
1450 &conservative_signals, 0, "Unprivileged processes prevented from "
1451 "sending certain signals to processes whose credentials have changed");
1452 /*-
1453 * Determine whether cred may deliver the specified signal to proc.
1454 * Returns: 0 for permitted, an errno value otherwise.
1455 * Locks: A lock must be held for proc.
1456 * References: cred and proc must be valid for the lifetime of the call.
1457 */
1458 int
1459 cr_cansignal(struct ucred *cred, struct proc *proc, int signum)
1460 {
1461 int error;
1462
1463 PROC_LOCK_ASSERT(proc, MA_OWNED);
1464 /*
1465 * Jail semantics limit the scope of signalling to proc in the
1466 * same jail as cred, if cred is in jail.
1467 */
1468 error = prison_check(cred, proc->p_ucred);
1469 if (error)
1470 return (error);
1471 #ifdef MAC
1472 if ((error = mac_proc_check_signal(cred, proc, signum)))
1473 return (error);
1474 #endif
1475 if ((error = cr_seeotheruids(cred, proc->p_ucred)))
1476 return (error);
1477 if ((error = cr_seeothergids(cred, proc->p_ucred)))
1478 return (error);
1479
1480 /*
1481 * UNIX signal semantics depend on the status of the P_SUGID
1482 * bit on the target process. If the bit is set, then additional
1483 * restrictions are placed on the set of available signals.
1484 */
1485 if (conservative_signals && (proc->p_flag & P_SUGID)) {
1486 switch (signum) {
1487 case 0:
1488 case SIGKILL:
1489 case SIGINT:
1490 case SIGTERM:
1491 case SIGALRM:
1492 case SIGSTOP:
1493 case SIGTTIN:
1494 case SIGTTOU:
1495 case SIGTSTP:
1496 case SIGHUP:
1497 case SIGUSR1:
1498 case SIGUSR2:
1499 /*
1500 * Generally, permit job and terminal control
1501 * signals.
1502 */
1503 break;
1504 default:
1505 /* Not permitted without privilege. */
1506 error = priv_check_cred(cred, PRIV_SIGNAL_SUGID, 0);
1507 if (error)
1508 return (error);
1509 }
1510 }
1511
1512 /*
1513 * Generally, the target credential's ruid or svuid must match the
1514 * subject credential's ruid or euid.
1515 */
1516 if (cred->cr_ruid != proc->p_ucred->cr_ruid &&
1517 cred->cr_ruid != proc->p_ucred->cr_svuid &&
1518 cred->cr_uid != proc->p_ucred->cr_ruid &&
1519 cred->cr_uid != proc->p_ucred->cr_svuid) {
1520 error = priv_check_cred(cred, PRIV_SIGNAL_DIFFCRED, 0);
1521 if (error)
1522 return (error);
1523 }
1524
1525 return (0);
1526 }
1527
1528 /*-
1529 * Determine whether td may deliver the specified signal to p.
1530 * Returns: 0 for permitted, an errno value otherwise
1531 * Locks: Sufficient locks to protect various components of td and p
1532 * must be held. td must be curthread, and a lock must be
1533 * held for p.
1534 * References: td and p must be valid for the lifetime of the call
1535 */
1536 int
1537 p_cansignal(struct thread *td, struct proc *p, int signum)
1538 {
1539
1540 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1541 PROC_LOCK_ASSERT(p, MA_OWNED);
1542 if (td->td_proc == p)
1543 return (0);
1544
1545 /*
1546 * UNIX signalling semantics require that processes in the same
1547 * session always be able to deliver SIGCONT to one another,
1548 * overriding the remaining protections.
1549 */
1550 /* XXX: This will require an additional lock of some sort. */
1551 if (signum == SIGCONT && td->td_proc->p_session == p->p_session)
1552 return (0);
1553 /*
1554 * Some compat layers use SIGTHR and higher signals for
1555 * communication between different kernel threads of the same
1556 * process, so that they expect that it's always possible to
1557 * deliver them, even for suid applications where cr_cansignal() can
1558 * deny such ability for security consideration. It should be
1559 * pretty safe to do since the only way to create two processes
1560 * with the same p_leader is via rfork(2).
1561 */
1562 if (td->td_proc->p_leader != NULL && signum >= SIGTHR &&
1563 signum < SIGTHR + 4 && td->td_proc->p_leader == p->p_leader)
1564 return (0);
1565
1566 return (cr_cansignal(td->td_ucred, p, signum));
1567 }
1568
1569 /*-
1570 * Determine whether td may reschedule p.
1571 * Returns: 0 for permitted, an errno value otherwise
1572 * Locks: Sufficient locks to protect various components of td and p
1573 * must be held. td must be curthread, and a lock must
1574 * be held for p.
1575 * References: td and p must be valid for the lifetime of the call
1576 */
1577 int
1578 p_cansched(struct thread *td, struct proc *p)
1579 {
1580 int error;
1581
1582 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1583 PROC_LOCK_ASSERT(p, MA_OWNED);
1584 if (td->td_proc == p)
1585 return (0);
1586 if ((error = prison_check(td->td_ucred, p->p_ucred)))
1587 return (error);
1588 #ifdef MAC
1589 if ((error = mac_proc_check_sched(td->td_ucred, p)))
1590 return (error);
1591 #endif
1592 if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
1593 return (error);
1594 if ((error = cr_seeothergids(td->td_ucred, p->p_ucred)))
1595 return (error);
1596 if (td->td_ucred->cr_ruid != p->p_ucred->cr_ruid &&
1597 td->td_ucred->cr_uid != p->p_ucred->cr_ruid) {
1598 error = priv_check(td, PRIV_SCHED_DIFFCRED);
1599 if (error)
1600 return (error);
1601 }
1602 return (0);
1603 }
1604
1605 /*
1606 * The 'unprivileged_proc_debug' flag may be used to disable a variety of
1607 * unprivileged inter-process debugging services, including some procfs
1608 * functionality, ptrace(), and ktrace(). In the past, inter-process
1609 * debugging has been involved in a variety of security problems, and sites
1610 * not requiring the service might choose to disable it when hardening
1611 * systems.
1612 *
1613 * XXX: Should modifying and reading this variable require locking?
1614 * XXX: data declarations should be together near the beginning of the file.
1615 */
1616 static int unprivileged_proc_debug = 1;
1617 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_proc_debug, CTLFLAG_RW,
1618 &unprivileged_proc_debug, 0,
1619 "Unprivileged processes may use process debugging facilities");
1620
1621 /*-
1622 * Determine whether td may debug p.
1623 * Returns: 0 for permitted, an errno value otherwise
1624 * Locks: Sufficient locks to protect various components of td and p
1625 * must be held. td must be curthread, and a lock must
1626 * be held for p.
1627 * References: td and p must be valid for the lifetime of the call
1628 */
1629 int
1630 p_candebug(struct thread *td, struct proc *p)
1631 {
1632 int credentialchanged, error, grpsubset, i, uidsubset;
1633
1634 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1635 PROC_LOCK_ASSERT(p, MA_OWNED);
1636 if (!unprivileged_proc_debug) {
1637 error = priv_check(td, PRIV_DEBUG_UNPRIV);
1638 if (error)
1639 return (error);
1640 }
1641 if (td->td_proc == p)
1642 return (0);
1643 if ((error = prison_check(td->td_ucred, p->p_ucred)))
1644 return (error);
1645 #ifdef MAC
1646 if ((error = mac_proc_check_debug(td->td_ucred, p)))
1647 return (error);
1648 #endif
1649 if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
1650 return (error);
1651 if ((error = cr_seeothergids(td->td_ucred, p->p_ucred)))
1652 return (error);
1653
1654 /*
1655 * Is p's group set a subset of td's effective group set? This
1656 * includes p's egid, group access list, rgid, and svgid.
1657 */
1658 grpsubset = 1;
1659 for (i = 0; i < p->p_ucred->cr_ngroups; i++) {
1660 if (!groupmember(p->p_ucred->cr_groups[i], td->td_ucred)) {
1661 grpsubset = 0;
1662 break;
1663 }
1664 }
1665 grpsubset = grpsubset &&
1666 groupmember(p->p_ucred->cr_rgid, td->td_ucred) &&
1667 groupmember(p->p_ucred->cr_svgid, td->td_ucred);
1668
1669 /*
1670 * Are the uids present in p's credential equal to td's
1671 * effective uid? This includes p's euid, svuid, and ruid.
1672 */
1673 uidsubset = (td->td_ucred->cr_uid == p->p_ucred->cr_uid &&
1674 td->td_ucred->cr_uid == p->p_ucred->cr_svuid &&
1675 td->td_ucred->cr_uid == p->p_ucred->cr_ruid);
1676
1677 /*
1678 * Has the credential of the process changed since the last exec()?
1679 */
1680 credentialchanged = (p->p_flag & P_SUGID);
1681
1682 /*
1683 * If p's gids aren't a subset, or the uids aren't a subset,
1684 * or the credential has changed, require appropriate privilege
1685 * for td to debug p.
1686 */
1687 if (!grpsubset || !uidsubset) {
1688 error = priv_check(td, PRIV_DEBUG_DIFFCRED);
1689 if (error)
1690 return (error);
1691 }
1692
1693 if (credentialchanged) {
1694 error = priv_check(td, PRIV_DEBUG_SUGID);
1695 if (error)
1696 return (error);
1697 }
1698
1699 /* Can't trace init when securelevel > 0. */
1700 if (p == initproc) {
1701 error = securelevel_gt(td->td_ucred, 0);
1702 if (error)
1703 return (error);
1704 }
1705
1706 /*
1707 * Can't trace a process that's currently exec'ing.
1708 *
1709 * XXX: Note, this is not a security policy decision, it's a
1710 * basic correctness/functionality decision. Therefore, this check
1711 * should be moved to the caller's of p_candebug().
1712 */
1713 if ((p->p_flag & P_INEXEC) != 0)
1714 return (EBUSY);
1715
1716 /* Denied explicitely */
1717 if ((p->p_flag2 & P2_NOTRACE) != 0) {
1718 error = priv_check(td, PRIV_DEBUG_DENIED);
1719 if (error != 0)
1720 return (error);
1721 }
1722
1723 return (0);
1724 }
1725
1726 /*-
1727 * Determine whether the subject represented by cred can "see" a socket.
1728 * Returns: 0 for permitted, ENOENT otherwise.
1729 */
1730 int
1731 cr_canseesocket(struct ucred *cred, struct socket *so)
1732 {
1733 int error;
1734
1735 error = prison_check(cred, so->so_cred);
1736 if (error)
1737 return (ENOENT);
1738 #ifdef MAC
1739 error = mac_socket_check_visible(cred, so);
1740 if (error)
1741 return (error);
1742 #endif
1743 if (cr_seeotheruids(cred, so->so_cred))
1744 return (ENOENT);
1745 if (cr_seeothergids(cred, so->so_cred))
1746 return (ENOENT);
1747
1748 return (0);
1749 }
1750
1751 #if defined(INET) || defined(INET6)
1752 /*-
1753 * Determine whether the subject represented by cred can "see" a socket.
1754 * Returns: 0 for permitted, ENOENT otherwise.
1755 */
1756 int
1757 cr_canseeinpcb(struct ucred *cred, struct inpcb *inp)
1758 {
1759 int error;
1760
1761 error = prison_check(cred, inp->inp_cred);
1762 if (error)
1763 return (ENOENT);
1764 #ifdef MAC
1765 INP_LOCK_ASSERT(inp);
1766 error = mac_inpcb_check_visible(cred, inp);
1767 if (error)
1768 return (error);
1769 #endif
1770 if (cr_seeotheruids(cred, inp->inp_cred))
1771 return (ENOENT);
1772 if (cr_seeothergids(cred, inp->inp_cred))
1773 return (ENOENT);
1774
1775 return (0);
1776 }
1777 #endif
1778
1779 /*-
1780 * Determine whether td can wait for the exit of p.
1781 * Returns: 0 for permitted, an errno value otherwise
1782 * Locks: Sufficient locks to protect various components of td and p
1783 * must be held. td must be curthread, and a lock must
1784 * be held for p.
1785 * References: td and p must be valid for the lifetime of the call
1786
1787 */
1788 int
1789 p_canwait(struct thread *td, struct proc *p)
1790 {
1791 int error;
1792
1793 KASSERT(td == curthread, ("%s: td not curthread", __func__));
1794 PROC_LOCK_ASSERT(p, MA_OWNED);
1795 if ((error = prison_check(td->td_ucred, p->p_ucred)))
1796 return (error);
1797 #ifdef MAC
1798 if ((error = mac_proc_check_wait(td->td_ucred, p)))
1799 return (error);
1800 #endif
1801 #if 0
1802 /* XXXMAC: This could have odd effects on some shells. */
1803 if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
1804 return (error);
1805 #endif
1806
1807 return (0);
1808 }
1809
1810 /*
1811 * Allocate a zeroed cred structure.
1812 */
1813 struct ucred *
1814 crget(void)
1815 {
1816 register struct ucred *cr;
1817
1818 cr = malloc(sizeof(*cr), M_CRED, M_WAITOK | M_ZERO);
1819 refcount_init(&cr->cr_ref, 1);
1820 #ifdef AUDIT
1821 audit_cred_init(cr);
1822 #endif
1823 #ifdef MAC
1824 mac_cred_init(cr);
1825 #endif
1826 cr->cr_groups = cr->cr_smallgroups;
1827 cr->cr_agroups =
1828 sizeof(cr->cr_smallgroups) / sizeof(cr->cr_smallgroups[0]);
1829 return (cr);
1830 }
1831
1832 /*
1833 * Claim another reference to a ucred structure.
1834 */
1835 struct ucred *
1836 crhold(struct ucred *cr)
1837 {
1838
1839 refcount_acquire(&cr->cr_ref);
1840 return (cr);
1841 }
1842
1843 /*
1844 * Free a cred structure. Throws away space when ref count gets to 0.
1845 */
1846 void
1847 crfree(struct ucred *cr)
1848 {
1849
1850 KASSERT(cr->cr_ref > 0, ("bad ucred refcount: %d", cr->cr_ref));
1851 KASSERT(cr->cr_ref != 0xdeadc0de, ("dangling reference to ucred"));
1852 if (refcount_release(&cr->cr_ref)) {
1853 /*
1854 * Some callers of crget(), such as nfs_statfs(),
1855 * allocate a temporary credential, but don't
1856 * allocate a uidinfo structure.
1857 */
1858 if (cr->cr_uidinfo != NULL)
1859 uifree(cr->cr_uidinfo);
1860 if (cr->cr_ruidinfo != NULL)
1861 uifree(cr->cr_ruidinfo);
1862 /*
1863 * Free a prison, if any.
1864 */
1865 if (cr->cr_prison != NULL)
1866 prison_free(cr->cr_prison);
1867 if (cr->cr_loginclass != NULL)
1868 loginclass_free(cr->cr_loginclass);
1869 #ifdef AUDIT
1870 audit_cred_destroy(cr);
1871 #endif
1872 #ifdef MAC
1873 mac_cred_destroy(cr);
1874 #endif
1875 if (cr->cr_groups != cr->cr_smallgroups)
1876 free(cr->cr_groups, M_CRED);
1877 free(cr, M_CRED);
1878 }
1879 }
1880
1881 /*
1882 * Copy a ucred's contents from a template. Does not block.
1883 */
1884 void
1885 crcopy(struct ucred *dest, struct ucred *src)
1886 {
1887
1888 KASSERT(dest->cr_ref == 1, ("crcopy of shared ucred"));
1889 bcopy(&src->cr_startcopy, &dest->cr_startcopy,
1890 (unsigned)((caddr_t)&src->cr_endcopy -
1891 (caddr_t)&src->cr_startcopy));
1892 crsetgroups(dest, src->cr_ngroups, src->cr_groups);
1893 uihold(dest->cr_uidinfo);
1894 uihold(dest->cr_ruidinfo);
1895 prison_hold(dest->cr_prison);
1896 loginclass_hold(dest->cr_loginclass);
1897 #ifdef AUDIT
1898 audit_cred_copy(src, dest);
1899 #endif
1900 #ifdef MAC
1901 mac_cred_copy(src, dest);
1902 #endif
1903 }
1904
1905 /*
1906 * Dup cred struct to a new held one.
1907 */
1908 struct ucred *
1909 crdup(struct ucred *cr)
1910 {
1911 struct ucred *newcr;
1912
1913 newcr = crget();
1914 crcopy(newcr, cr);
1915 return (newcr);
1916 }
1917
1918 /*
1919 * Fill in a struct xucred based on a struct ucred.
1920 */
1921 void
1922 cru2x(struct ucred *cr, struct xucred *xcr)
1923 {
1924 int ngroups;
1925
1926 bzero(xcr, sizeof(*xcr));
1927 xcr->cr_version = XUCRED_VERSION;
1928 xcr->cr_uid = cr->cr_uid;
1929
1930 ngroups = MIN(cr->cr_ngroups, XU_NGROUPS);
1931 xcr->cr_ngroups = ngroups;
1932 bcopy(cr->cr_groups, xcr->cr_groups,
1933 ngroups * sizeof(*cr->cr_groups));
1934 }
1935
1936 /*
1937 * Set initial process credentials.
1938 * Callers are responsible for providing the reference for provided credentials.
1939 */
1940 void
1941 proc_set_cred_init(struct proc *p, struct ucred *newcred)
1942 {
1943
1944 p->p_ucred = newcred;
1945 }
1946
1947 /*
1948 * Change process credentials.
1949 * Callers are responsible for providing the reference for passed credentials
1950 * and for freeing old ones.
1951 *
1952 * Process has to be locked except when it does not have credentials (as it
1953 * should not be visible just yet) or when newcred is NULL (as this can be
1954 * only used when the process is about to be freed, at which point it should
1955 * not be visible anymore).
1956 */
1957 struct ucred *
1958 proc_set_cred(struct proc *p, struct ucred *newcred)
1959 {
1960 struct ucred *oldcred;
1961
1962 MPASS(p->p_ucred != NULL);
1963 if (newcred == NULL)
1964 MPASS(p->p_state == PRS_ZOMBIE);
1965 else
1966 PROC_LOCK_ASSERT(p, MA_OWNED);
1967
1968 oldcred = p->p_ucred;
1969 p->p_ucred = newcred;
1970 if (newcred != NULL)
1971 PROC_UPDATE_COW(p);
1972 return (oldcred);
1973 }
1974
1975 struct ucred *
1976 crcopysafe(struct proc *p, struct ucred *cr)
1977 {
1978 struct ucred *oldcred;
1979 int groups;
1980
1981 PROC_LOCK_ASSERT(p, MA_OWNED);
1982
1983 oldcred = p->p_ucred;
1984 while (cr->cr_agroups < oldcred->cr_agroups) {
1985 groups = oldcred->cr_agroups;
1986 PROC_UNLOCK(p);
1987 crextend(cr, groups);
1988 PROC_LOCK(p);
1989 oldcred = p->p_ucred;
1990 }
1991 crcopy(cr, oldcred);
1992
1993 return (oldcred);
1994 }
1995
1996 /*
1997 * Extend the passed in credential to hold n items.
1998 */
1999 void
2000 crextend(struct ucred *cr, int n)
2001 {
2002 int cnt;
2003
2004 /* Truncate? */
2005 if (n <= cr->cr_agroups)
2006 return;
2007
2008 /*
2009 * We extend by 2 each time since we're using a power of two
2010 * allocator until we need enough groups to fill a page.
2011 * Once we're allocating multiple pages, only allocate as many
2012 * as we actually need. The case of processes needing a
2013 * non-power of two number of pages seems more likely than
2014 * a real world process that adds thousands of groups one at a
2015 * time.
2016 */
2017 if ( n < PAGE_SIZE / sizeof(gid_t) ) {
2018 if (cr->cr_agroups == 0)
2019 cnt = MINALLOCSIZE / sizeof(gid_t);
2020 else
2021 cnt = cr->cr_agroups * 2;
2022
2023 while (cnt < n)
2024 cnt *= 2;
2025 } else
2026 cnt = roundup2(n, PAGE_SIZE / sizeof(gid_t));
2027
2028 /* Free the old array. */
2029 if (cr->cr_groups != cr->cr_smallgroups)
2030 free(cr->cr_groups, M_CRED);
2031
2032 cr->cr_groups = malloc(cnt * sizeof(gid_t), M_CRED, M_WAITOK | M_ZERO);
2033 cr->cr_agroups = cnt;
2034 }
2035
2036 /*
2037 * Copy groups in to a credential, preserving any necessary invariants.
2038 * Currently this includes the sorting of all supplemental gids.
2039 * crextend() must have been called before hand to ensure sufficient
2040 * space is available.
2041 */
2042 static void
2043 crsetgroups_locked(struct ucred *cr, int ngrp, gid_t *groups)
2044 {
2045 int i;
2046 int j;
2047 gid_t g;
2048
2049 KASSERT(cr->cr_agroups >= ngrp, ("cr_ngroups is too small"));
2050
2051 bcopy(groups, cr->cr_groups, ngrp * sizeof(gid_t));
2052 cr->cr_ngroups = ngrp;
2053
2054 /*
2055 * Sort all groups except cr_groups[0] to allow groupmember to
2056 * perform a binary search.
2057 *
2058 * XXX: If large numbers of groups become common this should
2059 * be replaced with shell sort like linux uses or possibly
2060 * heap sort.
2061 */
2062 for (i = 2; i < ngrp; i++) {
2063 g = cr->cr_groups[i];
2064 for (j = i-1; j >= 1 && g < cr->cr_groups[j]; j--)
2065 cr->cr_groups[j + 1] = cr->cr_groups[j];
2066 cr->cr_groups[j + 1] = g;
2067 }
2068 }
2069
2070 /*
2071 * Copy groups in to a credential after expanding it if required.
2072 * Truncate the list to (ngroups_max + 1) if it is too large.
2073 */
2074 void
2075 crsetgroups(struct ucred *cr, int ngrp, gid_t *groups)
2076 {
2077
2078 if (ngrp > ngroups_max + 1)
2079 ngrp = ngroups_max + 1;
2080
2081 crextend(cr, ngrp);
2082 crsetgroups_locked(cr, ngrp, groups);
2083 }
2084
2085 /*
2086 * Get login name, if available.
2087 */
2088 #ifndef _SYS_SYSPROTO_H_
2089 struct getlogin_args {
2090 char *namebuf;
2091 u_int namelen;
2092 };
2093 #endif
2094 /* ARGSUSED */
2095 int
2096 sys_getlogin(struct thread *td, struct getlogin_args *uap)
2097 {
2098 char login[MAXLOGNAME];
2099 struct proc *p = td->td_proc;
2100 size_t len;
2101
2102 if (uap->namelen > MAXLOGNAME)
2103 uap->namelen = MAXLOGNAME;
2104 PROC_LOCK(p);
2105 SESS_LOCK(p->p_session);
2106 len = strlcpy(login, p->p_session->s_login, uap->namelen) + 1;
2107 SESS_UNLOCK(p->p_session);
2108 PROC_UNLOCK(p);
2109 if (len > uap->namelen)
2110 return (ERANGE);
2111 return (copyout(login, uap->namebuf, len));
2112 }
2113
2114 /*
2115 * Set login name.
2116 */
2117 #ifndef _SYS_SYSPROTO_H_
2118 struct setlogin_args {
2119 char *namebuf;
2120 };
2121 #endif
2122 /* ARGSUSED */
2123 int
2124 sys_setlogin(struct thread *td, struct setlogin_args *uap)
2125 {
2126 struct proc *p = td->td_proc;
2127 int error;
2128 char logintmp[MAXLOGNAME];
2129
2130 CTASSERT(sizeof(p->p_session->s_login) >= sizeof(logintmp));
2131
2132 error = priv_check(td, PRIV_PROC_SETLOGIN);
2133 if (error)
2134 return (error);
2135 error = copyinstr(uap->namebuf, logintmp, sizeof(logintmp), NULL);
2136 if (error != 0) {
2137 if (error == ENAMETOOLONG)
2138 error = EINVAL;
2139 return (error);
2140 }
2141 PROC_LOCK(p);
2142 SESS_LOCK(p->p_session);
2143 strcpy(p->p_session->s_login, logintmp);
2144 SESS_UNLOCK(p->p_session);
2145 PROC_UNLOCK(p);
2146 return (0);
2147 }
2148
2149 void
2150 setsugid(struct proc *p)
2151 {
2152
2153 PROC_LOCK_ASSERT(p, MA_OWNED);
2154 p->p_flag |= P_SUGID;
2155 if (!(p->p_pfsflags & PF_ISUGID))
2156 p->p_stops = 0;
2157 }
2158
2159 /*-
2160 * Change a process's effective uid.
2161 * Side effects: newcred->cr_uid and newcred->cr_uidinfo will be modified.
2162 * References: newcred must be an exclusive credential reference for the
2163 * duration of the call.
2164 */
2165 void
2166 change_euid(struct ucred *newcred, struct uidinfo *euip)
2167 {
2168
2169 newcred->cr_uid = euip->ui_uid;
2170 uihold(euip);
2171 uifree(newcred->cr_uidinfo);
2172 newcred->cr_uidinfo = euip;
2173 }
2174
2175 /*-
2176 * Change a process's effective gid.
2177 * Side effects: newcred->cr_gid will be modified.
2178 * References: newcred must be an exclusive credential reference for the
2179 * duration of the call.
2180 */
2181 void
2182 change_egid(struct ucred *newcred, gid_t egid)
2183 {
2184
2185 newcred->cr_groups[0] = egid;
2186 }
2187
2188 /*-
2189 * Change a process's real uid.
2190 * Side effects: newcred->cr_ruid will be updated, newcred->cr_ruidinfo
2191 * will be updated, and the old and new cr_ruidinfo proc
2192 * counts will be updated.
2193 * References: newcred must be an exclusive credential reference for the
2194 * duration of the call.
2195 */
2196 void
2197 change_ruid(struct ucred *newcred, struct uidinfo *ruip)
2198 {
2199
2200 (void)chgproccnt(newcred->cr_ruidinfo, -1, 0);
2201 newcred->cr_ruid = ruip->ui_uid;
2202 uihold(ruip);
2203 uifree(newcred->cr_ruidinfo);
2204 newcred->cr_ruidinfo = ruip;
2205 (void)chgproccnt(newcred->cr_ruidinfo, 1, 0);
2206 }
2207
2208 /*-
2209 * Change a process's real gid.
2210 * Side effects: newcred->cr_rgid will be updated.
2211 * References: newcred must be an exclusive credential reference for the
2212 * duration of the call.
2213 */
2214 void
2215 change_rgid(struct ucred *newcred, gid_t rgid)
2216 {
2217
2218 newcred->cr_rgid = rgid;
2219 }
2220
2221 /*-
2222 * Change a process's saved uid.
2223 * Side effects: newcred->cr_svuid will be updated.
2224 * References: newcred must be an exclusive credential reference for the
2225 * duration of the call.
2226 */
2227 void
2228 change_svuid(struct ucred *newcred, uid_t svuid)
2229 {
2230
2231 newcred->cr_svuid = svuid;
2232 }
2233
2234 /*-
2235 * Change a process's saved gid.
2236 * Side effects: newcred->cr_svgid will be updated.
2237 * References: newcred must be an exclusive credential reference for the
2238 * duration of the call.
2239 */
2240 void
2241 change_svgid(struct ucred *newcred, gid_t svgid)
2242 {
2243
2244 newcred->cr_svgid = svgid;
2245 }
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