1 | /* |
2 | * Copyright (c) 2000-2008 Apple Inc. All rights reserved. |
3 | * |
4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
5 | * |
6 | * This file contains Original Code and/or Modifications of Original Code |
7 | * as defined in and that are subject to the Apple Public Source License |
8 | * Version 2.0 (the 'License'). You may not use this file except in |
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10 | * may not be used to create, or enable the creation or redistribution of, |
11 | * unlawful or unlicensed copies of an Apple operating system, or to |
12 | * circumvent, violate, or enable the circumvention or violation of, any |
13 | * terms of an Apple operating system software license agreement. |
14 | * |
15 | * Please obtain a copy of the License at |
16 | * http://www.opensource.apple.com/apsl/ and read it before using this file. |
17 | * |
18 | * The Original Code and all software distributed under the License are |
19 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
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23 | * Please see the License for the specific language governing rights and |
24 | * limitations under the License. |
25 | * |
26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
27 | * |
28 | * |
29 | * Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved |
30 | * |
31 | * |
32 | * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993 |
33 | * The Regents of the University of California. All rights reserved. |
34 | * (c) UNIX System Laboratories, Inc. |
35 | * All or some portions of this file are derived from material licensed |
36 | * to the University of California by American Telephone and Telegraph |
37 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
38 | * the permission of UNIX System Laboratories, Inc. |
39 | * |
40 | * Redistribution and use in source and binary forms, with or without |
41 | * modification, are permitted provided that the following conditions |
42 | * are met: |
43 | * 1. Redistributions of source code must retain the above copyright |
44 | * notice, this list of conditions and the following disclaimer. |
45 | * 2. Redistributions in binary form must reproduce the above copyright |
46 | * notice, this list of conditions and the following disclaimer in the |
47 | * documentation and/or other materials provided with the distribution. |
48 | * 3. All advertising materials mentioning features or use of this software |
49 | * must display the following acknowledgement: |
50 | * This product includes software developed by the University of |
51 | * California, Berkeley and its contributors. |
52 | * 4. Neither the name of the University nor the names of its contributors |
53 | * may be used to endorse or promote products derived from this software |
54 | * without specific prior written permission. |
55 | * |
56 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
57 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
58 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
59 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
60 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
61 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
62 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
63 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
64 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
65 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
66 | * SUCH DAMAGE. |
67 | * |
68 | * @(#)kern_prot.c 8.9 (Berkeley) 2/14/95 |
69 | * |
70 | * |
71 | * NOTICE: This file was modified by McAfee Research in 2004 to introduce |
72 | * support for mandatory and extensible security protections. This notice |
73 | * is included in support of clause 2.2 (b) of the Apple Public License, |
74 | * Version 2.0. |
75 | * |
76 | * |
77 | * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce |
78 | * support for mandatory and extensible security protections. This notice |
79 | * is included in support of clause 2.2 (b) of the Apple Public License, |
80 | * Version 2.0. |
81 | * |
82 | */ |
83 | |
84 | /* |
85 | * System calls related to processes and protection |
86 | */ |
87 | |
88 | #include <sys/param.h> |
89 | #include <sys/acct.h> |
90 | #include <sys/systm.h> |
91 | #include <sys/ucred.h> |
92 | #include <sys/proc_internal.h> |
93 | #include <sys/user.h> |
94 | #include <sys/kauth.h> |
95 | #include <sys/timeb.h> |
96 | #include <sys/times.h> |
97 | #include <sys/malloc.h> |
98 | #include <sys/persona.h> |
99 | |
100 | #include <security/audit/audit.h> |
101 | |
102 | #if CONFIG_MACF |
103 | #include <security/mac_framework.h> |
104 | #endif |
105 | |
106 | #include <sys/mount_internal.h> |
107 | #include <sys/sysproto.h> |
108 | #include <mach/message.h> |
109 | #include <mach/host_security.h> |
110 | |
111 | #include <kern/host.h> |
112 | #include <kern/task.h> /* for current_task() */ |
113 | #include <kern/assert.h> |
114 | |
115 | |
116 | /* |
117 | * Credential debugging; we can track entry into a function that might |
118 | * change a credential, and we can track actual credential changes that |
119 | * result. |
120 | * |
121 | * Note: Does *NOT* currently include per-thread credential changes |
122 | * |
123 | * We don't use kauth_cred_print() in current debugging, but it |
124 | * can be used if needed when debugging is active. |
125 | */ |
126 | #if DEBUG_CRED |
127 | #define DEBUG_CRED_ENTER printf |
128 | #define DEBUG_CRED_CHANGE printf |
129 | extern void kauth_cred_print(kauth_cred_t cred); |
130 | #else /* !DEBUG_CRED */ |
131 | #define DEBUG_CRED_ENTER(fmt, ...) do {} while (0) |
132 | #define DEBUG_CRED_CHANGE(fmt, ...) do {} while (0) |
133 | #endif /* !DEBUG_CRED */ |
134 | |
135 | #if DEVELOPMENT || DEBUG |
136 | extern void task_importance_update_owner_info(task_t); |
137 | #endif |
138 | |
139 | |
140 | /* |
141 | * setprivexec |
142 | * |
143 | * Description: (dis)allow this process to hold task, thread, or execption |
144 | * ports of processes about to exec. |
145 | * |
146 | * Parameters: uap->flag New value for flag |
147 | * |
148 | * Returns: int Previous value of flag |
149 | * |
150 | * XXX: Belongs in kern_proc.c |
151 | */ |
152 | int |
153 | setprivexec(proc_t p, struct setprivexec_args *uap, int32_t *retval) |
154 | { |
155 | AUDIT_ARG(value32, uap->flag); |
156 | *retval = p->p_debugger; |
157 | p->p_debugger = (uap->flag != 0); |
158 | return(0); |
159 | } |
160 | |
161 | |
162 | /* |
163 | * getpid |
164 | * |
165 | * Description: get the process ID |
166 | * |
167 | * Parameters: (void) |
168 | * |
169 | * Returns: pid_t Current process ID |
170 | * |
171 | * XXX: Belongs in kern_proc.c |
172 | */ |
173 | int |
174 | getpid(proc_t p, __unused struct getpid_args *uap, int32_t *retval) |
175 | { |
176 | |
177 | *retval = p->p_pid; |
178 | return (0); |
179 | } |
180 | |
181 | |
182 | /* |
183 | * getppid |
184 | * |
185 | * Description: get the parent process ID |
186 | * |
187 | * Parameters: (void) |
188 | * |
189 | * Returns: pid_t Parent process ID |
190 | * |
191 | * XXX: Belongs in kern_proc.c |
192 | */ |
193 | int |
194 | getppid(proc_t p, __unused struct getppid_args *uap, int32_t *retval) |
195 | { |
196 | |
197 | *retval = p->p_ppid; |
198 | return (0); |
199 | } |
200 | |
201 | |
202 | /* |
203 | * getpgrp |
204 | * |
205 | * Description: get the process group ID of the calling process |
206 | * |
207 | * Parameters: (void) |
208 | * |
209 | * Returns: pid_t Process group ID |
210 | * |
211 | * XXX: Belongs in kern_proc.c |
212 | */ |
213 | int |
214 | getpgrp(proc_t p, __unused struct getpgrp_args *uap, int32_t *retval) |
215 | { |
216 | |
217 | *retval = p->p_pgrpid; |
218 | return (0); |
219 | } |
220 | |
221 | |
222 | /* |
223 | * getpgid |
224 | * |
225 | * Description: Get an arbitary pid's process group id |
226 | * |
227 | * Parameters: uap->pid The target pid |
228 | * |
229 | * Returns: 0 Success |
230 | * ESRCH No such process |
231 | * |
232 | * Notes: We are permitted to return EPERM in the case that the target |
233 | * process is not in the same session as the calling process, |
234 | * which could be a security consideration |
235 | * |
236 | * XXX: Belongs in kern_proc.c |
237 | */ |
238 | int |
239 | getpgid(proc_t p, struct getpgid_args *uap, int32_t *retval) |
240 | { |
241 | proc_t pt; |
242 | int refheld = 0; |
243 | |
244 | pt = p; |
245 | if (uap->pid == 0) |
246 | goto found; |
247 | |
248 | if ((pt = proc_find(uap->pid)) == 0) |
249 | return (ESRCH); |
250 | refheld = 1; |
251 | found: |
252 | *retval = pt->p_pgrpid; |
253 | if (refheld != 0) |
254 | proc_rele(pt); |
255 | return (0); |
256 | } |
257 | |
258 | |
259 | /* |
260 | * getsid |
261 | * |
262 | * Description: Get an arbitary pid's session leaders process group ID |
263 | * |
264 | * Parameters: uap->pid The target pid |
265 | * |
266 | * Returns: 0 Success |
267 | * ESRCH No such process |
268 | * |
269 | * Notes: We are permitted to return EPERM in the case that the target |
270 | * process is not in the same session as the calling process, |
271 | * which could be a security consideration |
272 | * |
273 | * XXX: Belongs in kern_proc.c |
274 | */ |
275 | int |
276 | getsid(proc_t p, struct getsid_args *uap, int32_t *retval) |
277 | { |
278 | proc_t pt; |
279 | int refheld = 0; |
280 | struct session * sessp; |
281 | |
282 | pt = p; |
283 | if (uap->pid == 0) |
284 | goto found; |
285 | |
286 | if ((pt = proc_find(uap->pid)) == 0) |
287 | return (ESRCH); |
288 | refheld = 1; |
289 | found: |
290 | sessp = proc_session(pt); |
291 | *retval = sessp->s_sid; |
292 | session_rele(sessp); |
293 | |
294 | if (refheld != 0) |
295 | proc_rele(pt); |
296 | return (0); |
297 | } |
298 | |
299 | |
300 | /* |
301 | * getuid |
302 | * |
303 | * Description: get real user ID for caller |
304 | * |
305 | * Parameters: (void) |
306 | * |
307 | * Returns: uid_t The real uid of the caller |
308 | */ |
309 | int |
310 | getuid(__unused proc_t p, __unused struct getuid_args *uap, int32_t *retval) |
311 | { |
312 | |
313 | *retval = kauth_getruid(); |
314 | return (0); |
315 | } |
316 | |
317 | |
318 | /* |
319 | * geteuid |
320 | * |
321 | * Description: get effective user ID for caller |
322 | * |
323 | * Parameters: (void) |
324 | * |
325 | * Returns: uid_t The effective uid of the caller |
326 | */ |
327 | int |
328 | geteuid(__unused proc_t p, __unused struct geteuid_args *uap, int32_t *retval) |
329 | { |
330 | |
331 | *retval = kauth_getuid(); |
332 | return (0); |
333 | } |
334 | |
335 | |
336 | /* |
337 | * gettid |
338 | * |
339 | * Description: Return the per-thread override identity. |
340 | * |
341 | * Parameters: uap->uidp Address of uid_t to get uid |
342 | * uap->gidp Address of gid_t to get gid |
343 | * |
344 | * Returns: 0 Success |
345 | * ESRCH No per thread identity active |
346 | */ |
347 | int |
348 | gettid(__unused proc_t p, struct gettid_args *uap, int32_t *retval) |
349 | { |
350 | struct uthread *uthread = get_bsdthread_info(current_thread()); |
351 | int error; |
352 | |
353 | /* |
354 | * If this thread is not running with an override identity, we can't |
355 | * return one to the caller, so return an error instead. |
356 | */ |
357 | if (!(uthread->uu_flag & UT_SETUID)) |
358 | return (ESRCH); |
359 | |
360 | if ((error = suword(uap->uidp, kauth_cred_getruid(uthread->uu_ucred)))) |
361 | return (error); |
362 | if ((error = suword(uap->gidp, kauth_cred_getrgid(uthread->uu_ucred)))) |
363 | return (error); |
364 | |
365 | *retval = 0; |
366 | return (0); |
367 | } |
368 | |
369 | |
370 | /* |
371 | * getgid |
372 | * |
373 | * Description: get the real group ID for the calling process |
374 | * |
375 | * Parameters: (void) |
376 | * |
377 | * Returns: gid_t The real gid of the caller |
378 | */ |
379 | int |
380 | getgid(__unused proc_t p, __unused struct getgid_args *uap, int32_t *retval) |
381 | { |
382 | |
383 | *retval = kauth_getrgid(); |
384 | return (0); |
385 | } |
386 | |
387 | |
388 | /* |
389 | * getegid |
390 | * |
391 | * Description: get the effective group ID for the calling process |
392 | * |
393 | * Parameters: (void) |
394 | * |
395 | * Returns: gid_t The effective gid of the caller |
396 | * |
397 | * Notes: As an implementation detail, the effective gid is stored as |
398 | * the first element of the supplementary group list. |
399 | * |
400 | * This could be implemented in Libc instead because of the above |
401 | * detail. |
402 | */ |
403 | int |
404 | getegid(__unused proc_t p, __unused struct getegid_args *uap, int32_t *retval) |
405 | { |
406 | |
407 | *retval = kauth_getgid(); |
408 | return (0); |
409 | } |
410 | |
411 | |
412 | /* |
413 | * getgroups |
414 | * |
415 | * Description: get the list of supplementary groups for the calling process |
416 | * |
417 | * Parameters: uap->gidsetsize # of gid_t's in user buffer |
418 | * uap->gidset Pointer to user buffer |
419 | * |
420 | * Returns: 0 Success |
421 | * EINVAL User buffer too small |
422 | * copyout:EFAULT User buffer invalid |
423 | * |
424 | * Retval: -1 Error |
425 | * !0 # of groups |
426 | * |
427 | * Notes: The caller may specify a 0 value for gidsetsize, and we will |
428 | * then return how large a buffer is required (in gid_t's) to |
429 | * contain the answer at the time of the call. Otherwise, we |
430 | * return the number of gid_t's catually copied to user space. |
431 | * |
432 | * When called with a 0 gidsetsize from a multithreaded program, |
433 | * there is no guarantee that another thread may not change the |
434 | * number of supplementary groups, and therefore a subsequent |
435 | * call could still fail, unless the maximum possible buffer |
436 | * size is supplied by the user. |
437 | * |
438 | * As an implementation detail, the effective gid is stored as |
439 | * the first element of the supplementary group list, and will |
440 | * be returned by this call. |
441 | */ |
442 | int |
443 | getgroups(__unused proc_t p, struct getgroups_args *uap, int32_t *retval) |
444 | { |
445 | int ngrp; |
446 | int error; |
447 | kauth_cred_t cred; |
448 | posix_cred_t pcred; |
449 | |
450 | /* grab reference while we muck around with the credential */ |
451 | cred = kauth_cred_get_with_ref(); |
452 | pcred = posix_cred_get(cred); |
453 | |
454 | if ((ngrp = uap->gidsetsize) == 0) { |
455 | *retval = pcred->cr_ngroups; |
456 | kauth_cred_unref(&cred); |
457 | return (0); |
458 | } |
459 | if (ngrp < pcred->cr_ngroups) { |
460 | kauth_cred_unref(&cred); |
461 | return (EINVAL); |
462 | } |
463 | ngrp = pcred->cr_ngroups; |
464 | if ((error = copyout((caddr_t)pcred->cr_groups, |
465 | uap->gidset, |
466 | ngrp * sizeof(gid_t)))) { |
467 | kauth_cred_unref(&cred); |
468 | return (error); |
469 | } |
470 | kauth_cred_unref(&cred); |
471 | *retval = ngrp; |
472 | return (0); |
473 | } |
474 | |
475 | |
476 | /* |
477 | * Return the per-thread/per-process supplementary groups list. |
478 | * |
479 | * XXX implement getsgroups |
480 | * |
481 | */ |
482 | |
483 | int |
484 | getsgroups(__unused proc_t p, __unused struct getsgroups_args *uap, __unused int32_t *retval) |
485 | { |
486 | return(ENOTSUP); |
487 | } |
488 | |
489 | /* |
490 | * Return the per-thread/per-process whiteout groups list. |
491 | * |
492 | * XXX implement getwgroups |
493 | * |
494 | */ |
495 | |
496 | int |
497 | getwgroups(__unused proc_t p, __unused struct getwgroups_args *uap, __unused int32_t *retval) |
498 | { |
499 | return(ENOTSUP); |
500 | } |
501 | |
502 | |
503 | /* |
504 | * setsid |
505 | * |
506 | * Description: Create a new session and set the process group ID to the |
507 | * session ID |
508 | * |
509 | * Parameters: (void) |
510 | * |
511 | * Returns: 0 Success |
512 | * EPERM Permission denied |
513 | * |
514 | * Notes: If the calling process is not the process group leader; there |
515 | * is no existing process group with its ID, and we are not |
516 | * currently in vfork, then this function will create a new |
517 | * session, a new process group, and put the caller in the |
518 | * process group (as the sole member) and make it the session |
519 | * leader (as the sole process in the session). |
520 | * |
521 | * The existing controlling tty (if any) will be dissociated |
522 | * from the process, and the next non-O_NOCTTY open of a tty |
523 | * will establish a new controlling tty. |
524 | * |
525 | * XXX: Belongs in kern_proc.c |
526 | */ |
527 | int |
528 | setsid(proc_t p, __unused struct setsid_args *uap, int32_t *retval) |
529 | { |
530 | struct pgrp * pg = PGRP_NULL; |
531 | |
532 | if (p->p_pgrpid == p->p_pid || (pg = pgfind(p->p_pid)) || p->p_lflag & P_LINVFORK) { |
533 | if (pg != PGRP_NULL) |
534 | pg_rele(pg); |
535 | return (EPERM); |
536 | } else { |
537 | /* enter pgrp works with its own pgrp refcount */ |
538 | (void)enterpgrp(p, p->p_pid, 1); |
539 | *retval = p->p_pid; |
540 | return (0); |
541 | } |
542 | } |
543 | |
544 | |
545 | /* |
546 | * setpgid |
547 | * |
548 | * Description: set process group ID for job control |
549 | * |
550 | * Parameters: uap->pid Process to change |
551 | * uap->pgid Process group to join or create |
552 | * |
553 | * Returns: 0 Success |
554 | * ESRCH pid is not the caller or a child of |
555 | * the caller |
556 | * enterpgrp:ESRCH No such process |
557 | * EACCES Permission denied due to exec |
558 | * EINVAL Invalid argument |
559 | * EPERM The target process is not in the same |
560 | * session as the calling process |
561 | * EPERM The target process is a session leader |
562 | * EPERM pid and pgid are not the same, and |
563 | * there is no process in the calling |
564 | * process whose process group ID matches |
565 | * pgid |
566 | * |
567 | * Notes: This function will cause the target process to either join |
568 | * an existing process process group, or create a new process |
569 | * group in the session of the calling process. It cannot be |
570 | * used to change the process group ID of a process which is |
571 | * already a session leader. |
572 | * |
573 | * If the target pid is 0, the pid of the calling process is |
574 | * substituted as the new target; if pgid is 0, the target pid |
575 | * is used as the target process group ID. |
576 | * |
577 | * Legacy: This system call entry point is also used to implement the |
578 | * legacy library routine setpgrp(), which under POSIX |
579 | * |
580 | * XXX: Belongs in kern_proc.c |
581 | */ |
582 | int |
583 | setpgid(proc_t curp, struct setpgid_args *uap, __unused int32_t *retval) |
584 | { |
585 | proc_t targp = PROC_NULL; /* target process */ |
586 | struct pgrp *pg = PGRP_NULL; /* target pgrp */ |
587 | int error = 0; |
588 | int refheld = 0; |
589 | int samesess = 0; |
590 | struct session * curp_sessp = SESSION_NULL; |
591 | struct session * targp_sessp = SESSION_NULL; |
592 | |
593 | curp_sessp = proc_session(curp); |
594 | |
595 | if (uap->pid != 0 && uap->pid != curp->p_pid) { |
596 | if ((targp = proc_find(uap->pid)) == 0 || !inferior(targp)) { |
597 | if (targp != PROC_NULL) |
598 | refheld = 1; |
599 | error = ESRCH; |
600 | goto out; |
601 | } |
602 | refheld = 1; |
603 | targp_sessp = proc_session(targp); |
604 | if (targp_sessp != curp_sessp) { |
605 | error = EPERM; |
606 | goto out; |
607 | } |
608 | if (targp->p_flag & P_EXEC) { |
609 | error = EACCES; |
610 | goto out; |
611 | } |
612 | } else { |
613 | targp = curp; |
614 | targp_sessp = proc_session(targp); |
615 | } |
616 | |
617 | if (SESS_LEADER(targp, targp_sessp)) { |
618 | error = EPERM; |
619 | goto out; |
620 | } |
621 | if (targp_sessp != SESSION_NULL) { |
622 | session_rele(targp_sessp); |
623 | targp_sessp = SESSION_NULL; |
624 | } |
625 | |
626 | if (uap->pgid < 0) { |
627 | error = EINVAL; |
628 | goto out; |
629 | } |
630 | if (uap->pgid == 0) |
631 | uap->pgid = targp->p_pid; |
632 | else if (uap->pgid != targp->p_pid) { |
633 | if ((pg = pgfind(uap->pgid)) == 0){ |
634 | error = EPERM; |
635 | goto out; |
636 | } |
637 | samesess = (pg->pg_session != curp_sessp); |
638 | pg_rele(pg); |
639 | if (samesess != 0) { |
640 | error = EPERM; |
641 | goto out; |
642 | } |
643 | } |
644 | error = enterpgrp(targp, uap->pgid, 0); |
645 | out: |
646 | if (targp_sessp != SESSION_NULL) |
647 | session_rele(targp_sessp); |
648 | if (curp_sessp != SESSION_NULL) |
649 | session_rele(curp_sessp); |
650 | if (refheld != 0) |
651 | proc_rele(targp); |
652 | return(error); |
653 | } |
654 | |
655 | |
656 | /* |
657 | * issetugid |
658 | * |
659 | * Description: Is current process tainted by uid or gid changes system call |
660 | * |
661 | * Parameters: (void) |
662 | * |
663 | * Returns: 0 Not tainted |
664 | * 1 Tainted |
665 | * |
666 | * Notes: A process is considered tainted if it was created as a retult |
667 | * of an execve call from an imnage that had either the SUID or |
668 | * SGID bit set on the executable, or if it has changed any of its |
669 | * real, effective, or saved user or group IDs since beginning |
670 | * execution. |
671 | */ |
672 | int |
673 | proc_issetugid (proc_t p) |
674 | { |
675 | return (p->p_flag & P_SUGID) ? 1 : 0; |
676 | } |
677 | |
678 | int |
679 | issetugid(proc_t p, __unused struct issetugid_args *uap, int32_t *retval) |
680 | { |
681 | /* |
682 | * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time, |
683 | * we use P_SUGID because we consider changing the owners as |
684 | * "tainting" as well. |
685 | * This is significant for procs that start as root and "become" |
686 | * a user without an exec - programs cannot know *everything* |
687 | * that libc *might* have put in their data segment. |
688 | */ |
689 | |
690 | *retval = proc_issetugid(p); |
691 | return (0); |
692 | } |
693 | |
694 | |
695 | /* |
696 | * setuid |
697 | * |
698 | * Description: Set user ID system call |
699 | * |
700 | * Parameters: uap->uid uid to set |
701 | * |
702 | * Returns: 0 Success |
703 | * suser:EPERM Permission denied |
704 | * |
705 | * Notes: If called by a privileged process, this function will set the |
706 | * real, effective, and saved uid to the requested value. |
707 | * |
708 | * If called from an unprivileged process, but uid is equal to the |
709 | * real or saved uid, then the effective uid will be set to the |
710 | * requested value, but the real and saved uid will not change. |
711 | * |
712 | * If the credential is changed as a result of this call, then we |
713 | * flag the process as having set privilege since the last exec. |
714 | */ |
715 | int |
716 | setuid(proc_t p, struct setuid_args *uap, __unused int32_t *retval) |
717 | { |
718 | uid_t uid; |
719 | uid_t svuid = KAUTH_UID_NONE; |
720 | uid_t ruid = KAUTH_UID_NONE; |
721 | uid_t gmuid = KAUTH_UID_NONE; |
722 | int error; |
723 | kauth_cred_t my_cred, my_new_cred; |
724 | posix_cred_t my_pcred; |
725 | |
726 | uid = uap->uid; |
727 | |
728 | /* get current credential and take a reference while we muck with it */ |
729 | my_cred = kauth_cred_proc_ref(p); |
730 | my_pcred = posix_cred_get(my_cred); |
731 | |
732 | DEBUG_CRED_ENTER("setuid (%d/%d): %p %d\n" , p->p_pid, (p->p_pptr ? p->p_pptr->p_pid : 0), my_cred, uap->uid); |
733 | AUDIT_ARG(uid, uid); |
734 | |
735 | for (;;) { |
736 | if (uid != my_pcred->cr_ruid && /* allow setuid(getuid()) */ |
737 | uid != my_pcred->cr_svuid && /* allow setuid(saved uid) */ |
738 | (error = suser(my_cred, &p->p_acflag))) { |
739 | kauth_cred_unref(&my_cred); |
740 | return (error); |
741 | } |
742 | |
743 | /* |
744 | * If we are privileged, then set the saved and real UID too; |
745 | * otherwise, just set the effective UID |
746 | */ |
747 | if (suser(my_cred, &p->p_acflag) == 0) { |
748 | svuid = uid; |
749 | ruid = uid; |
750 | } else { |
751 | svuid = KAUTH_UID_NONE; |
752 | ruid = KAUTH_UID_NONE; |
753 | } |
754 | /* |
755 | * Only set the gmuid if the current cred has not opt'ed out; |
756 | * this normally only happens when calling setgroups() instead |
757 | * of initgroups() to set an explicit group list, or one of the |
758 | * other group manipulation functions is invoked and results in |
759 | * a dislocation (i.e. the credential group membership changes |
760 | * to something other than the default list for the user, as |
761 | * in entering a group or leaving an exclusion group). |
762 | */ |
763 | if (!(my_pcred->cr_flags & CRF_NOMEMBERD)) |
764 | gmuid = uid; |
765 | |
766 | /* |
767 | * Set the credential with new info. If there is no change, |
768 | * we get back the same credential we passed in; if there is |
769 | * a change, we drop the reference on the credential we |
770 | * passed in. The subsequent compare is safe, because it is |
771 | * a pointer compare rather than a contents compare. |
772 | */ |
773 | my_new_cred = kauth_cred_setresuid(my_cred, ruid, uid, svuid, gmuid); |
774 | if (my_cred != my_new_cred) { |
775 | |
776 | DEBUG_CRED_CHANGE("setuid CH(%d): %p/0x%08x -> %p/0x%08x\n" , p->p_pid, my_cred, my_pcred->cr_flags, my_new_cred, posix_cred_get(my_new_cred)->cr_flags); |
777 | |
778 | /* |
779 | * If we're changing the ruid from A to B, we might race with another thread that's setting ruid from B to A. |
780 | * The current locking mechanisms don't allow us to make the entire credential switch operation atomic, |
781 | * thus we may be able to change the process credentials from ruid A to B, but get preempted before incrementing the proc |
782 | * count of B. If a second thread sees the new process credentials and switches back to ruid A, that other thread |
783 | * may be able to decrement the proc count of B before we can increment it. This results in a panic. |
784 | * Incrementing the proc count of the target ruid, B, before setting the process credentials prevents this race. |
785 | */ |
786 | if (ruid != KAUTH_UID_NONE && !proc_has_persona(p)) { |
787 | (void)chgproccnt(ruid, 1); |
788 | } |
789 | |
790 | proc_ucred_lock(p); |
791 | /* |
792 | * We need to protect for a race where another thread |
793 | * also changed the credential after we took our |
794 | * reference. If p_ucred has changed then we should |
795 | * restart this again with the new cred. |
796 | * |
797 | * Note: the kauth_cred_setresuid has consumed a reference to my_cred, it p_ucred != my_cred, then my_cred must not be dereferenced! |
798 | */ |
799 | if (p->p_ucred != my_cred) { |
800 | proc_ucred_unlock(p); |
801 | /* |
802 | * We didn't successfully switch to the new ruid, so decrement |
803 | * the procs/uid count that we incremented above. |
804 | */ |
805 | if (ruid != KAUTH_UID_NONE && !proc_has_persona(p)) { |
806 | (void)chgproccnt(ruid, -1); |
807 | } |
808 | kauth_cred_unref(&my_new_cred); |
809 | my_cred = kauth_cred_proc_ref(p); |
810 | my_pcred = posix_cred_get(my_cred); |
811 | /* try again */ |
812 | continue; |
813 | } |
814 | p->p_ucred = my_new_cred; |
815 | /* update cred on proc */ |
816 | PROC_UPDATE_CREDS_ONPROC(p); |
817 | |
818 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
819 | proc_ucred_unlock(p); |
820 | /* |
821 | * If we've updated the ruid, decrement the count of procs running |
822 | * under the previous ruid |
823 | */ |
824 | if (ruid != KAUTH_UID_NONE && !proc_has_persona(p)) { |
825 | (void)chgproccnt(my_pcred->cr_ruid, -1); |
826 | } |
827 | } |
828 | break; |
829 | } |
830 | /* Drop old proc reference or our extra reference */ |
831 | kauth_cred_unref(&my_cred); |
832 | |
833 | set_security_token(p); |
834 | return (0); |
835 | } |
836 | |
837 | |
838 | /* |
839 | * seteuid |
840 | * |
841 | * Description: Set effective user ID system call |
842 | * |
843 | * Parameters: uap->euid effective uid to set |
844 | * |
845 | * Returns: 0 Success |
846 | * suser:EPERM Permission denied |
847 | * |
848 | * Notes: If called by a privileged process, or called from an |
849 | * unprivileged process but euid is equal to the real or saved |
850 | * uid, then the effective uid will be set to the requested |
851 | * value, but the real and saved uid will not change. |
852 | * |
853 | * If the credential is changed as a result of this call, then we |
854 | * flag the process as having set privilege since the last exec. |
855 | */ |
856 | int |
857 | seteuid(proc_t p, struct seteuid_args *uap, __unused int32_t *retval) |
858 | { |
859 | uid_t euid; |
860 | int error; |
861 | kauth_cred_t my_cred, my_new_cred; |
862 | posix_cred_t my_pcred; |
863 | |
864 | DEBUG_CRED_ENTER("seteuid: %d\n" , uap->euid); |
865 | |
866 | euid = uap->euid; |
867 | AUDIT_ARG(euid, euid); |
868 | |
869 | my_cred = kauth_cred_proc_ref(p); |
870 | my_pcred = posix_cred_get(my_cred); |
871 | |
872 | for (;;) { |
873 | |
874 | if (euid != my_pcred->cr_ruid && euid != my_pcred->cr_svuid && |
875 | (error = suser(my_cred, &p->p_acflag))) { |
876 | kauth_cred_unref(&my_cred); |
877 | return (error); |
878 | } |
879 | |
880 | /* |
881 | * Set the credential with new info. If there is no change, |
882 | * we get back the same credential we passed in; if there is |
883 | * a change, we drop the reference on the credential we |
884 | * passed in. The subsequent compare is safe, because it is |
885 | * a pointer compare rather than a contents compare. |
886 | */ |
887 | my_new_cred = kauth_cred_setresuid(my_cred, KAUTH_UID_NONE, euid, KAUTH_UID_NONE, my_pcred->cr_gmuid); |
888 | |
889 | if (my_cred != my_new_cred) { |
890 | |
891 | DEBUG_CRED_CHANGE("seteuid CH(%d): %p/0x%08x -> %p/0x%08x\n" , p->p_pid, my_cred, my_pcred->cr_flags, my_new_cred, posix_cred_get(my_new_cred)->cr_flags); |
892 | |
893 | proc_ucred_lock(p); |
894 | /* |
895 | * We need to protect for a race where another thread |
896 | * also changed the credential after we took our |
897 | * reference. If p_ucred has changed then we |
898 | * should restart this again with the new cred. |
899 | */ |
900 | if (p->p_ucred != my_cred) { |
901 | proc_ucred_unlock(p); |
902 | kauth_cred_unref(&my_new_cred); |
903 | my_cred = kauth_cred_proc_ref(p); |
904 | my_pcred = posix_cred_get(my_cred); |
905 | /* try again */ |
906 | continue; |
907 | } |
908 | p->p_ucred = my_new_cred; |
909 | /* update cred on proc */ |
910 | PROC_UPDATE_CREDS_ONPROC(p); |
911 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
912 | proc_ucred_unlock(p); |
913 | } |
914 | break; |
915 | } |
916 | /* drop old proc reference or our extra reference */ |
917 | kauth_cred_unref(&my_cred); |
918 | |
919 | set_security_token(p); |
920 | return (0); |
921 | } |
922 | |
923 | |
924 | /* |
925 | * setreuid |
926 | * |
927 | * Description: Set real and effective user ID system call |
928 | * |
929 | * Parameters: uap->ruid real uid to set |
930 | * uap->euid effective uid to set |
931 | * |
932 | * Returns: 0 Success |
933 | * suser:EPERM Permission denied |
934 | * |
935 | * Notes: A value of -1 is a special case indicating that the uid for |
936 | * which that value is specified not be changed. If both values |
937 | * are specified as -1, no action is taken. |
938 | * |
939 | * If called by a privileged process, the real and effective uid |
940 | * will be set to the new value(s) specified. |
941 | * |
942 | * If called from an unprivileged process, the real uid may be |
943 | * set to the current value of the real uid, or to the current |
944 | * value of the saved uid. The effective uid may be set to the |
945 | * current value of any of the effective, real, or saved uid. |
946 | * |
947 | * If the newly requested real uid or effective uid does not |
948 | * match the saved uid, then set the saved uid to the new |
949 | * effective uid (potentially unrecoverably dropping saved |
950 | * privilege). |
951 | * |
952 | * If the credential is changed as a result of this call, then we |
953 | * flag the process as having set privilege since the last exec. |
954 | */ |
955 | int |
956 | setreuid(proc_t p, struct setreuid_args *uap, __unused int32_t *retval) |
957 | { |
958 | uid_t ruid, euid; |
959 | int error; |
960 | kauth_cred_t my_cred, my_new_cred; |
961 | posix_cred_t my_pcred; |
962 | |
963 | DEBUG_CRED_ENTER("setreuid %d %d\n" , uap->ruid, uap->euid); |
964 | |
965 | ruid = uap->ruid; |
966 | euid = uap->euid; |
967 | if (ruid == (uid_t)-1) |
968 | ruid = KAUTH_UID_NONE; |
969 | if (euid == (uid_t)-1) |
970 | euid = KAUTH_UID_NONE; |
971 | AUDIT_ARG(euid, euid); |
972 | AUDIT_ARG(ruid, ruid); |
973 | |
974 | my_cred = kauth_cred_proc_ref(p); |
975 | my_pcred = posix_cred_get(my_cred); |
976 | |
977 | for (;;) { |
978 | |
979 | if (((ruid != KAUTH_UID_NONE && /* allow no change of ruid */ |
980 | ruid != my_pcred->cr_ruid && /* allow ruid = ruid */ |
981 | ruid != my_pcred->cr_uid && /* allow ruid = euid */ |
982 | ruid != my_pcred->cr_svuid) || /* allow ruid = svuid */ |
983 | (euid != KAUTH_UID_NONE && /* allow no change of euid */ |
984 | euid != my_pcred->cr_uid && /* allow euid = euid */ |
985 | euid != my_pcred->cr_ruid && /* allow euid = ruid */ |
986 | euid != my_pcred->cr_svuid)) && /* allow euid = svuid */ |
987 | (error = suser(my_cred, &p->p_acflag))) { /* allow root user any */ |
988 | kauth_cred_unref(&my_cred); |
989 | return (error); |
990 | } |
991 | |
992 | uid_t new_euid; |
993 | uid_t svuid = KAUTH_UID_NONE; |
994 | |
995 | new_euid = my_pcred->cr_uid; |
996 | /* |
997 | * Set the credential with new info. If there is no change, |
998 | * we get back the same credential we passed in; if there is |
999 | * a change, we drop the reference on the credential we |
1000 | * passed in. The subsequent compare is safe, because it is |
1001 | * a pointer compare rather than a contents compare. |
1002 | */ |
1003 | if (euid != KAUTH_UID_NONE && my_pcred->cr_uid != euid) { |
1004 | /* changing the effective UID */ |
1005 | new_euid = euid; |
1006 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
1007 | } |
1008 | /* |
1009 | * If the newly requested real uid or effective uid does |
1010 | * not match the saved uid, then set the saved uid to the |
1011 | * new effective uid. We are protected from escalation |
1012 | * by the prechecking. |
1013 | */ |
1014 | if (my_pcred->cr_svuid != uap->ruid && |
1015 | my_pcred->cr_svuid != uap->euid) { |
1016 | svuid = new_euid; |
1017 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
1018 | } |
1019 | |
1020 | my_new_cred = kauth_cred_setresuid(my_cred, ruid, euid, svuid, my_pcred->cr_gmuid); |
1021 | |
1022 | if (my_cred != my_new_cred) { |
1023 | |
1024 | DEBUG_CRED_CHANGE("setreuid CH(%d): %p/0x%08x -> %p/0x%08x\n" , p->p_pid, my_cred, my_pcred->cr_flags, my_new_cred, posix_cred_get(my_new_cred)->cr_flags); |
1025 | |
1026 | /* |
1027 | * If we're changing the ruid from A to B, we might race with another thread that's setting ruid from B to A. |
1028 | * The current locking mechanisms don't allow us to make the entire credential switch operation atomic, |
1029 | * thus we may be able to change the process credentials from ruid A to B, but get preempted before incrementing the proc |
1030 | * count of B. If a second thread sees the new process credentials and switches back to ruid A, that other thread |
1031 | * may be able to decrement the proc count of B before we can increment it. This results in a panic. |
1032 | * Incrementing the proc count of the target ruid, B, before setting the process credentials prevents this race. |
1033 | */ |
1034 | if (ruid != KAUTH_UID_NONE && !proc_has_persona(p)) { |
1035 | (void)chgproccnt(ruid, 1); |
1036 | } |
1037 | |
1038 | proc_ucred_lock(p); |
1039 | /* |
1040 | * We need to protect for a race where another thread |
1041 | * also changed the credential after we took our |
1042 | * reference. If p_ucred has changed then we should |
1043 | * restart this again with the new cred. |
1044 | * |
1045 | * Note: the kauth_cred_setresuid has consumed a reference to my_cred, it p_ucred != my_cred, then my_cred must not be dereferenced! |
1046 | */ |
1047 | if (p->p_ucred != my_cred) { |
1048 | proc_ucred_unlock(p); |
1049 | if (ruid != KAUTH_UID_NONE && !proc_has_persona(p)) { |
1050 | /* |
1051 | * We didn't successfully switch to the new ruid, so decrement |
1052 | * the procs/uid count that we incremented above. |
1053 | */ |
1054 | (void)chgproccnt(ruid, -1); |
1055 | } |
1056 | kauth_cred_unref(&my_new_cred); |
1057 | my_cred = kauth_cred_proc_ref(p); |
1058 | my_pcred = posix_cred_get(my_cred); |
1059 | /* try again */ |
1060 | continue; |
1061 | } |
1062 | |
1063 | p->p_ucred = my_new_cred; |
1064 | /* update cred on proc */ |
1065 | PROC_UPDATE_CREDS_ONPROC(p); |
1066 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
1067 | proc_ucred_unlock(p); |
1068 | |
1069 | if (ruid != KAUTH_UID_NONE && !proc_has_persona(p)) { |
1070 | /* |
1071 | * We switched to a new ruid, so decrement the count of procs running |
1072 | * under the previous ruid |
1073 | */ |
1074 | (void)chgproccnt(my_pcred->cr_ruid, -1); |
1075 | } |
1076 | } |
1077 | break; |
1078 | } |
1079 | /* drop old proc reference or our extra reference */ |
1080 | kauth_cred_unref(&my_cred); |
1081 | |
1082 | set_security_token(p); |
1083 | return (0); |
1084 | } |
1085 | |
1086 | |
1087 | /* |
1088 | * setgid |
1089 | * |
1090 | * Description: Set group ID system call |
1091 | * |
1092 | * Parameters: uap->gid gid to set |
1093 | * |
1094 | * Returns: 0 Success |
1095 | * suser:EPERM Permission denied |
1096 | * |
1097 | * Notes: If called by a privileged process, this function will set the |
1098 | * real, effective, and saved gid to the requested value. |
1099 | * |
1100 | * If called from an unprivileged process, but gid is equal to the |
1101 | * real or saved gid, then the effective gid will be set to the |
1102 | * requested value, but the real and saved gid will not change. |
1103 | * |
1104 | * If the credential is changed as a result of this call, then we |
1105 | * flag the process as having set privilege since the last exec. |
1106 | * |
1107 | * As an implementation detail, the effective gid is stored as |
1108 | * the first element of the supplementary group list, and |
1109 | * therefore the effective group list may be reordered to keep |
1110 | * the supplementary group list unchanged. |
1111 | */ |
1112 | int |
1113 | setgid(proc_t p, struct setgid_args *uap, __unused int32_t *retval) |
1114 | { |
1115 | gid_t gid; |
1116 | gid_t rgid = KAUTH_GID_NONE; |
1117 | gid_t svgid = KAUTH_GID_NONE; |
1118 | int error; |
1119 | kauth_cred_t my_cred, my_new_cred; |
1120 | posix_cred_t my_pcred; |
1121 | |
1122 | DEBUG_CRED_ENTER("setgid(%d/%d): %d\n" , p->p_pid, (p->p_pptr ? p->p_pptr->p_pid : 0), uap->gid); |
1123 | |
1124 | gid = uap->gid; |
1125 | AUDIT_ARG(gid, gid); |
1126 | |
1127 | /* get current credential and take a reference while we muck with it */ |
1128 | my_cred = kauth_cred_proc_ref(p); |
1129 | my_pcred = posix_cred_get(my_cred); |
1130 | |
1131 | for (;;) { |
1132 | if (gid != my_pcred->cr_rgid && /* allow setgid(getgid()) */ |
1133 | gid != my_pcred->cr_svgid && /* allow setgid(saved gid) */ |
1134 | (error = suser(my_cred, &p->p_acflag))) { |
1135 | kauth_cred_unref(&my_cred); |
1136 | return (error); |
1137 | } |
1138 | |
1139 | /* |
1140 | * If we are privileged, then set the saved and real GID too; |
1141 | * otherwise, just set the effective GID |
1142 | */ |
1143 | if (suser(my_cred, &p->p_acflag) == 0) { |
1144 | svgid = gid; |
1145 | rgid = gid; |
1146 | } else { |
1147 | svgid = KAUTH_GID_NONE; |
1148 | rgid = KAUTH_GID_NONE; |
1149 | } |
1150 | |
1151 | /* |
1152 | * Set the credential with new info. If there is no change, |
1153 | * we get back the same credential we passed in; if there is |
1154 | * a change, we drop the reference on the credential we |
1155 | * passed in. The subsequent compare is safe, because it is |
1156 | * a pointer compare rather than a contents compare. |
1157 | */ |
1158 | my_new_cred = kauth_cred_setresgid(my_cred, rgid, gid, svgid); |
1159 | if (my_cred != my_new_cred) { |
1160 | |
1161 | DEBUG_CRED_CHANGE("setgid(CH)%d: %p/0x%08x->%p/0x%08x\n" , p->p_pid, my_cred, my_cred->cr_flags, my_new_cred, my_new_cred->cr_flags); |
1162 | |
1163 | proc_ucred_lock(p); |
1164 | /* |
1165 | * We need to protect for a race where another thread |
1166 | * also changed the credential after we took our |
1167 | * reference. If p_ucred has changed then we |
1168 | * should restart this again with the new cred. |
1169 | */ |
1170 | if (p->p_ucred != my_cred) { |
1171 | proc_ucred_unlock(p); |
1172 | kauth_cred_unref(&my_new_cred); |
1173 | /* try again */ |
1174 | my_cred = kauth_cred_proc_ref(p); |
1175 | my_pcred = posix_cred_get(my_cred); |
1176 | continue; |
1177 | } |
1178 | p->p_ucred = my_new_cred; |
1179 | /* update cred on proc */ |
1180 | PROC_UPDATE_CREDS_ONPROC(p); |
1181 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
1182 | proc_ucred_unlock(p); |
1183 | } |
1184 | break; |
1185 | } |
1186 | /* Drop old proc reference or our extra reference */ |
1187 | kauth_cred_unref(&my_cred); |
1188 | |
1189 | set_security_token(p); |
1190 | return (0); |
1191 | } |
1192 | |
1193 | |
1194 | /* |
1195 | * setegid |
1196 | * |
1197 | * Description: Set effective group ID system call |
1198 | * |
1199 | * Parameters: uap->egid effective gid to set |
1200 | * |
1201 | * Returns: 0 Success |
1202 | * suser:EPERM |
1203 | * |
1204 | * Notes: If called by a privileged process, or called from an |
1205 | * unprivileged process but egid is equal to the real or saved |
1206 | * gid, then the effective gid will be set to the requested |
1207 | * value, but the real and saved gid will not change. |
1208 | * |
1209 | * If the credential is changed as a result of this call, then we |
1210 | * flag the process as having set privilege since the last exec. |
1211 | * |
1212 | * As an implementation detail, the effective gid is stored as |
1213 | * the first element of the supplementary group list, and |
1214 | * therefore the effective group list may be reordered to keep |
1215 | * the supplementary group list unchanged. |
1216 | */ |
1217 | int |
1218 | setegid(proc_t p, struct setegid_args *uap, __unused int32_t *retval) |
1219 | { |
1220 | gid_t egid; |
1221 | int error; |
1222 | kauth_cred_t my_cred, my_new_cred; |
1223 | posix_cred_t my_pcred; |
1224 | |
1225 | DEBUG_CRED_ENTER("setegid %d\n" , uap->egid); |
1226 | |
1227 | egid = uap->egid; |
1228 | AUDIT_ARG(egid, egid); |
1229 | |
1230 | /* get current credential and take a reference while we muck with it */ |
1231 | my_cred = kauth_cred_proc_ref(p); |
1232 | my_pcred = posix_cred_get(my_cred); |
1233 | |
1234 | |
1235 | for (;;) { |
1236 | if (egid != my_pcred->cr_rgid && |
1237 | egid != my_pcred->cr_svgid && |
1238 | (error = suser(my_cred, &p->p_acflag))) { |
1239 | kauth_cred_unref(&my_cred); |
1240 | return (error); |
1241 | } |
1242 | /* |
1243 | * Set the credential with new info. If there is no change, |
1244 | * we get back the same credential we passed in; if there is |
1245 | * a change, we drop the reference on the credential we |
1246 | * passed in. The subsequent compare is safe, because it is |
1247 | * a pointer compare rather than a contents compare. |
1248 | */ |
1249 | my_new_cred = kauth_cred_setresgid(my_cred, KAUTH_GID_NONE, egid, KAUTH_GID_NONE); |
1250 | if (my_cred != my_new_cred) { |
1251 | |
1252 | DEBUG_CRED_CHANGE("setegid(CH)%d: %p/0x%08x->%p/0x%08x\n" , p->p_pid, my_cred, my_pcred->cr_flags, my_new_cred, posix_cred_get(my_new_cred)->cr_flags); |
1253 | |
1254 | proc_ucred_lock(p); |
1255 | /* |
1256 | * We need to protect for a race where another thread |
1257 | * also changed the credential after we took our |
1258 | * reference. If p_ucred has changed then we |
1259 | * should restart this again with the new cred. |
1260 | */ |
1261 | if (p->p_ucred != my_cred) { |
1262 | proc_ucred_unlock(p); |
1263 | kauth_cred_unref(&my_new_cred); |
1264 | /* try again */ |
1265 | my_cred = kauth_cred_proc_ref(p); |
1266 | my_pcred = posix_cred_get(my_cred); |
1267 | continue; |
1268 | } |
1269 | p->p_ucred = my_new_cred; |
1270 | /* update cred on proc */ |
1271 | PROC_UPDATE_CREDS_ONPROC(p); |
1272 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
1273 | proc_ucred_unlock(p); |
1274 | } |
1275 | break; |
1276 | } |
1277 | |
1278 | /* Drop old proc reference or our extra reference */ |
1279 | kauth_cred_unref(&my_cred); |
1280 | |
1281 | set_security_token(p); |
1282 | return (0); |
1283 | } |
1284 | |
1285 | /* |
1286 | * setregid |
1287 | * |
1288 | * Description: Set real and effective group ID system call |
1289 | * |
1290 | * Parameters: uap->rgid real gid to set |
1291 | * uap->egid effective gid to set |
1292 | * |
1293 | * Returns: 0 Success |
1294 | * suser:EPERM Permission denied |
1295 | * |
1296 | * Notes: A value of -1 is a special case indicating that the gid for |
1297 | * which that value is specified not be changed. If both values |
1298 | * are specified as -1, no action is taken. |
1299 | * |
1300 | * If called by a privileged process, the real and effective gid |
1301 | * will be set to the new value(s) specified. |
1302 | * |
1303 | * If called from an unprivileged process, the real gid may be |
1304 | * set to the current value of the real gid, or to the current |
1305 | * value of the saved gid. The effective gid may be set to the |
1306 | * current value of any of the effective, real, or saved gid. |
1307 | * |
1308 | * If the new real and effective gid will not be equal, or the |
1309 | * new real or effective gid is not the same as the saved gid, |
1310 | * then the saved gid will be updated to reflect the new |
1311 | * effective gid (potentially unrecoverably dropping saved |
1312 | * privilege). |
1313 | * |
1314 | * If the credential is changed as a result of this call, then we |
1315 | * flag the process as having set privilege since the last exec. |
1316 | * |
1317 | * As an implementation detail, the effective gid is stored as |
1318 | * the first element of the supplementary group list, and |
1319 | * therefore the effective group list may be reordered to keep |
1320 | * the supplementary group list unchanged. |
1321 | */ |
1322 | int |
1323 | setregid(proc_t p, struct setregid_args *uap, __unused int32_t *retval) |
1324 | { |
1325 | gid_t rgid, egid; |
1326 | int error; |
1327 | kauth_cred_t my_cred, my_new_cred; |
1328 | posix_cred_t my_pcred; |
1329 | |
1330 | DEBUG_CRED_ENTER("setregid %d %d\n" , uap->rgid, uap->egid); |
1331 | |
1332 | rgid = uap->rgid; |
1333 | egid = uap->egid; |
1334 | |
1335 | if (rgid == (uid_t)-1) |
1336 | rgid = KAUTH_GID_NONE; |
1337 | if (egid == (uid_t)-1) |
1338 | egid = KAUTH_GID_NONE; |
1339 | AUDIT_ARG(egid, egid); |
1340 | AUDIT_ARG(rgid, rgid); |
1341 | |
1342 | /* get current credential and take a reference while we muck with it */ |
1343 | my_cred = kauth_cred_proc_ref(p); |
1344 | my_pcred = posix_cred_get(my_cred); |
1345 | |
1346 | for (;;) { |
1347 | |
1348 | if (((rgid != KAUTH_UID_NONE && /* allow no change of rgid */ |
1349 | rgid != my_pcred->cr_rgid && /* allow rgid = rgid */ |
1350 | rgid != my_pcred->cr_gid && /* allow rgid = egid */ |
1351 | rgid != my_pcred->cr_svgid) || /* allow rgid = svgid */ |
1352 | (egid != KAUTH_UID_NONE && /* allow no change of egid */ |
1353 | egid != my_pcred->cr_groups[0] && /* allow no change of egid */ |
1354 | egid != my_pcred->cr_gid && /* allow egid = egid */ |
1355 | egid != my_pcred->cr_rgid && /* allow egid = rgid */ |
1356 | egid != my_pcred->cr_svgid)) && /* allow egid = svgid */ |
1357 | (error = suser(my_cred, &p->p_acflag))) { /* allow root user any */ |
1358 | kauth_cred_unref(&my_cred); |
1359 | return (error); |
1360 | } |
1361 | |
1362 | uid_t new_egid = my_pcred->cr_gid; |
1363 | uid_t new_rgid = my_pcred->cr_rgid; |
1364 | uid_t svgid = KAUTH_UID_NONE; |
1365 | |
1366 | |
1367 | /* |
1368 | * Set the credential with new info. If there is no change, |
1369 | * we get back the same credential we passed in; if there is |
1370 | * a change, we drop the reference on the credential we |
1371 | * passed in. The subsequent compare is safe, because it is |
1372 | * a pointer compare rather than a contents compare. |
1373 | */ |
1374 | if (egid != KAUTH_UID_NONE && my_pcred->cr_gid != egid) { |
1375 | /* changing the effective GID */ |
1376 | new_egid = egid; |
1377 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
1378 | } |
1379 | if (rgid != KAUTH_UID_NONE && my_pcred->cr_rgid != rgid) { |
1380 | /* changing the real GID */ |
1381 | new_rgid = rgid; |
1382 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
1383 | } |
1384 | /* |
1385 | * If the newly requested real gid or effective gid does |
1386 | * not match the saved gid, then set the saved gid to the |
1387 | * new effective gid. We are protected from escalation |
1388 | * by the prechecking. |
1389 | */ |
1390 | if (my_pcred->cr_svgid != uap->rgid && |
1391 | my_pcred->cr_svgid != uap->egid) { |
1392 | svgid = new_egid; |
1393 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
1394 | } |
1395 | |
1396 | my_new_cred = kauth_cred_setresgid(my_cred, rgid, egid, svgid); |
1397 | if (my_cred != my_new_cred) { |
1398 | |
1399 | DEBUG_CRED_CHANGE("setregid(CH)%d: %p/0x%08x->%p/0x%08x\n" , p->p_pid, my_cred, my_pcred->cr_flags, my_new_cred, posix_cred_get(my_new_cred)->cr_flags); |
1400 | |
1401 | proc_ucred_lock(p); |
1402 | /* need to protect for a race where another thread |
1403 | * also changed the credential after we took our |
1404 | * reference. If p_ucred has changed then we |
1405 | * should restart this again with the new cred. |
1406 | */ |
1407 | if (p->p_ucred != my_cred) { |
1408 | proc_ucred_unlock(p); |
1409 | kauth_cred_unref(&my_new_cred); |
1410 | /* try again */ |
1411 | my_cred = kauth_cred_proc_ref(p); |
1412 | my_pcred = posix_cred_get(my_cred); |
1413 | continue; |
1414 | } |
1415 | p->p_ucred = my_new_cred; |
1416 | /* update cred on proc */ |
1417 | PROC_UPDATE_CREDS_ONPROC(p); |
1418 | OSBitOrAtomic(P_SUGID, &p->p_flag); /* XXX redundant? */ |
1419 | proc_ucred_unlock(p); |
1420 | } |
1421 | break; |
1422 | } |
1423 | /* Drop old proc reference or our extra reference */ |
1424 | kauth_cred_unref(&my_cred); |
1425 | |
1426 | set_security_token(p); |
1427 | return (0); |
1428 | } |
1429 | |
1430 | |
1431 | /* |
1432 | * Set the per-thread override identity. The first parameter can be the |
1433 | * current real UID, KAUTH_UID_NONE, or, if the caller is privileged, it |
1434 | * can be any UID. If it is KAUTH_UID_NONE, then as a special case, this |
1435 | * means "revert to the per process credential"; otherwise, if permitted, |
1436 | * it changes the effective, real, and saved UIDs and GIDs for the current |
1437 | * thread to the requested UID and single GID, and clears all other GIDs. |
1438 | */ |
1439 | int |
1440 | settid(proc_t p, struct settid_args *uap, __unused int32_t *retval) |
1441 | { |
1442 | kauth_cred_t uc; |
1443 | struct uthread *uthread = get_bsdthread_info(current_thread()); |
1444 | uid_t uid; |
1445 | gid_t gid; |
1446 | |
1447 | uid = uap->uid; |
1448 | gid = uap->gid; |
1449 | AUDIT_ARG(uid, uid); |
1450 | AUDIT_ARG(gid, gid); |
1451 | |
1452 | if (proc_suser(p) != 0) |
1453 | return (EPERM); |
1454 | |
1455 | if (uid == KAUTH_UID_NONE) { |
1456 | |
1457 | /* must already be assuming another identity in order to revert back */ |
1458 | if ((uthread->uu_flag & UT_SETUID) == 0) |
1459 | return (EPERM); |
1460 | |
1461 | /* revert to delayed binding of process credential */ |
1462 | uc = kauth_cred_proc_ref(p); |
1463 | kauth_cred_unref(&uthread->uu_ucred); |
1464 | uthread->uu_ucred = uc; |
1465 | uthread->uu_flag &= ~UT_SETUID; |
1466 | } else { |
1467 | kauth_cred_t my_cred, my_new_cred; |
1468 | |
1469 | /* cannot already be assuming another identity */ |
1470 | if ((uthread->uu_flag & UT_SETUID) != 0) { |
1471 | return (EPERM); |
1472 | } |
1473 | |
1474 | /* |
1475 | * Get a new credential instance from the old if this one |
1476 | * changes; otherwise kauth_cred_setuidgid() returns the |
1477 | * same credential. We take an extra reference on the |
1478 | * current credential while we muck with it, so we can do |
1479 | * the post-compare for changes by pointer. |
1480 | */ |
1481 | kauth_cred_ref(uthread->uu_ucred); |
1482 | my_cred = uthread->uu_ucred; |
1483 | my_new_cred = kauth_cred_setuidgid(my_cred, uid, gid); |
1484 | if (my_cred != my_new_cred) |
1485 | uthread->uu_ucred = my_new_cred; |
1486 | uthread->uu_flag |= UT_SETUID; |
1487 | |
1488 | /* Drop old uthread reference or our extra reference */ |
1489 | kauth_cred_unref(&my_cred); |
1490 | } |
1491 | /* |
1492 | * XXX should potentially set per thread security token (there is |
1493 | * XXX none). |
1494 | * XXX it is unclear whether P_SUGID should be st at this point; |
1495 | * XXX in theory, it is being deprecated. |
1496 | */ |
1497 | return (0); |
1498 | } |
1499 | |
1500 | |
1501 | /* |
1502 | * Set the per-thread override identity. Use this system call for a thread to |
1503 | * assume the identity of another process or to revert back to normal identity |
1504 | * of the current process. |
1505 | * |
1506 | * When the "assume" argument is non zero the current thread will assume the |
1507 | * identity of the process represented by the pid argument. |
1508 | * |
1509 | * When the assume argument is zero we revert back to our normal identity. |
1510 | */ |
1511 | int |
1512 | settid_with_pid(proc_t p, struct settid_with_pid_args *uap, __unused int32_t *retval) |
1513 | { |
1514 | proc_t target_proc; |
1515 | struct uthread *uthread = get_bsdthread_info(current_thread()); |
1516 | kauth_cred_t my_cred, my_target_cred, my_new_cred; |
1517 | posix_cred_t my_target_pcred; |
1518 | |
1519 | AUDIT_ARG(pid, uap->pid); |
1520 | AUDIT_ARG(value32, uap->assume); |
1521 | |
1522 | if (proc_suser(p) != 0) { |
1523 | return (EPERM); |
1524 | } |
1525 | |
1526 | /* |
1527 | * XXX should potentially set per thread security token (there is |
1528 | * XXX none). |
1529 | * XXX it is unclear whether P_SUGID should be st at this point; |
1530 | * XXX in theory, it is being deprecated. |
1531 | */ |
1532 | |
1533 | /* |
1534 | * assume argument tells us to assume the identity of the process with the |
1535 | * id passed in the pid argument. |
1536 | */ |
1537 | if (uap->assume != 0) { |
1538 | /* can't do this if we have already assumed an identity */ |
1539 | if ((uthread->uu_flag & UT_SETUID) != 0) |
1540 | return (EPERM); |
1541 | |
1542 | target_proc = proc_find(uap->pid); |
1543 | /* can't assume the identity of the kernel process */ |
1544 | if (target_proc == NULL || target_proc == kernproc) { |
1545 | if (target_proc!= NULL) |
1546 | proc_rele(target_proc); |
1547 | return (ESRCH); |
1548 | } |
1549 | |
1550 | /* |
1551 | * Take a reference on the credential used in our target |
1552 | * process then use it as the identity for our current |
1553 | * thread. We take an extra reference on the current |
1554 | * credential while we muck with it, so we can do the |
1555 | * post-compare for changes by pointer. |
1556 | * |
1557 | * The post-compare is needed for the case that our process |
1558 | * credential has been changed to be identical to our thread |
1559 | * credential following our assumption of a per-thread one, |
1560 | * since the credential cache will maintain a unique instance. |
1561 | */ |
1562 | kauth_cred_ref(uthread->uu_ucred); |
1563 | my_cred = uthread->uu_ucred; |
1564 | my_target_cred = kauth_cred_proc_ref(target_proc); |
1565 | my_target_pcred = posix_cred_get(my_target_cred); |
1566 | my_new_cred = kauth_cred_setuidgid(my_cred, my_target_pcred->cr_uid, my_target_pcred->cr_gid); |
1567 | if (my_cred != my_new_cred) |
1568 | uthread->uu_ucred = my_new_cred; |
1569 | |
1570 | uthread->uu_flag |= UT_SETUID; |
1571 | |
1572 | /* Drop old uthread reference or our extra reference */ |
1573 | proc_rele(target_proc); |
1574 | kauth_cred_unref(&my_cred); |
1575 | kauth_cred_unref(&my_target_cred); |
1576 | |
1577 | return (0); |
1578 | } |
1579 | |
1580 | /* |
1581 | * Otherwise, we are reverting back to normal mode of operation where |
1582 | * delayed binding of the process credential sets the credential in |
1583 | * the thread (uu_ucred) |
1584 | */ |
1585 | if ((uthread->uu_flag & UT_SETUID) == 0) |
1586 | return (EPERM); |
1587 | |
1588 | /* revert to delayed binding of process credential */ |
1589 | my_new_cred = kauth_cred_proc_ref(p); |
1590 | kauth_cred_unref(&uthread->uu_ucred); |
1591 | uthread->uu_ucred = my_new_cred; |
1592 | uthread->uu_flag &= ~UT_SETUID; |
1593 | |
1594 | return (0); |
1595 | } |
1596 | |
1597 | |
1598 | /* |
1599 | * setgroups1 |
1600 | * |
1601 | * Description: Internal implementation for both the setgroups and initgroups |
1602 | * system calls |
1603 | * |
1604 | * Parameters: gidsetsize Number of groups in set |
1605 | * gidset Pointer to group list |
1606 | * gmuid Base gid (initgroups only!) |
1607 | * |
1608 | * Returns: 0 Success |
1609 | * suser:EPERM Permision denied |
1610 | * EINVAL Invalid gidsetsize value |
1611 | * copyin:EFAULT Bad gidset or gidsetsize is |
1612 | * too large |
1613 | * |
1614 | * Notes: When called from a thread running under an assumed per-thread |
1615 | * identity, this function will operate against the per-thread |
1616 | * credential, rather than against the process credential. In |
1617 | * this specific case, the process credential is verified to |
1618 | * still be privileged at the time of the call, rather than the |
1619 | * per-thread credential for this operation to be permitted. |
1620 | * |
1621 | * This effectively means that setgroups/initigroups calls in |
1622 | * a thread running a per-thread credential should occur *after* |
1623 | * the settid call that created it, not before (unlike setuid, |
1624 | * which must be called after, since it will result in privilege |
1625 | * being dropped). |
1626 | * |
1627 | * When called normally (i.e. no per-thread assumed identity), |
1628 | * the per process credential is updated per POSIX. |
1629 | * |
1630 | * If the credential is changed as a result of this call, then we |
1631 | * flag the process as having set privilege since the last exec. |
1632 | */ |
1633 | static int |
1634 | setgroups1(proc_t p, u_int gidsetsize, user_addr_t gidset, uid_t gmuid, __unused int32_t *retval) |
1635 | { |
1636 | u_int ngrp; |
1637 | gid_t newgroups[NGROUPS] = { 0 }; |
1638 | int error; |
1639 | kauth_cred_t my_cred, my_new_cred; |
1640 | struct uthread *uthread = get_bsdthread_info(current_thread()); |
1641 | |
1642 | DEBUG_CRED_ENTER("setgroups1 (%d/%d): %d 0x%016x %d\n" , p->p_pid, (p->p_pptr ? p->p_pptr->p_pid : 0), gidsetsize, gidset, gmuid); |
1643 | |
1644 | ngrp = gidsetsize; |
1645 | if (ngrp > NGROUPS) |
1646 | return (EINVAL); |
1647 | |
1648 | if ( ngrp < 1 ) { |
1649 | ngrp = 1; |
1650 | } else { |
1651 | error = copyin(gidset, |
1652 | (caddr_t)newgroups, ngrp * sizeof(gid_t)); |
1653 | if (error) { |
1654 | return (error); |
1655 | } |
1656 | } |
1657 | |
1658 | my_cred = kauth_cred_proc_ref(p); |
1659 | if ((error = suser(my_cred, &p->p_acflag))) { |
1660 | kauth_cred_unref(&my_cred); |
1661 | return (error); |
1662 | } |
1663 | |
1664 | if ((uthread->uu_flag & UT_SETUID) != 0) { |
1665 | #if DEBUG_CRED |
1666 | int my_cred_flags = uthread->uu_ucred->cr_flags; |
1667 | #endif /* DEBUG_CRED */ |
1668 | kauth_cred_unref(&my_cred); |
1669 | |
1670 | /* |
1671 | * If this thread is under an assumed identity, set the |
1672 | * supplementary grouplist on the thread credential instead |
1673 | * of the process one. If we were the only reference holder, |
1674 | * the credential is updated in place, otherwise, our reference |
1675 | * is dropped and we get back a different cred with a reference |
1676 | * already held on it. Because this is per-thread, we don't |
1677 | * need the referencing/locking/retry required for per-process. |
1678 | */ |
1679 | my_cred = uthread->uu_ucred; |
1680 | uthread->uu_ucred = kauth_cred_setgroups(my_cred, &newgroups[0], ngrp, gmuid); |
1681 | #if DEBUG_CRED |
1682 | if (my_cred != uthread->uu_ucred) { |
1683 | DEBUG_CRED_CHANGE("setgroups1(CH)%d: %p/0x%08x->%p/0x%08x\n" , p->p_pid, my_cred, my_cred_flags, uthread->uu_ucred , uthread->uu_ucred ->cr_flags); |
1684 | } |
1685 | #endif /* DEBUG_CRED */ |
1686 | } else { |
1687 | |
1688 | /* |
1689 | * get current credential and take a reference while we muck |
1690 | * with it |
1691 | */ |
1692 | for (;;) { |
1693 | /* |
1694 | * Set the credential with new info. If there is no |
1695 | * change, we get back the same credential we passed |
1696 | * in; if there is a change, we drop the reference on |
1697 | * the credential we passed in. The subsequent |
1698 | * compare is safe, because it is a pointer compare |
1699 | * rather than a contents compare. |
1700 | */ |
1701 | my_new_cred = kauth_cred_setgroups(my_cred, &newgroups[0], ngrp, gmuid); |
1702 | if (my_cred != my_new_cred) { |
1703 | |
1704 | DEBUG_CRED_CHANGE("setgroups1(CH)%d: %p/0x%08x->%p/0x%08x\n" , p->p_pid, my_cred, my_cred->cr_flags, my_new_cred, my_new_cred->cr_flags); |
1705 | |
1706 | proc_ucred_lock(p); |
1707 | /* |
1708 | * We need to protect for a race where another |
1709 | * thread also changed the credential after we |
1710 | * took our reference. If p_ucred has |
1711 | * changed then we should restart this again |
1712 | * with the new cred. |
1713 | */ |
1714 | if (p->p_ucred != my_cred) { |
1715 | proc_ucred_unlock(p); |
1716 | kauth_cred_unref(&my_new_cred); |
1717 | my_cred = kauth_cred_proc_ref(p); |
1718 | /* try again */ |
1719 | continue; |
1720 | } |
1721 | p->p_ucred = my_new_cred; |
1722 | /* update cred on proc */ |
1723 | PROC_UPDATE_CREDS_ONPROC(p); |
1724 | OSBitOrAtomic(P_SUGID, &p->p_flag); |
1725 | proc_ucred_unlock(p); |
1726 | } |
1727 | break; |
1728 | } |
1729 | /* Drop old proc reference or our extra reference */ |
1730 | AUDIT_ARG(groupset, posix_cred_get(my_cred)->cr_groups, ngrp); |
1731 | kauth_cred_unref(&my_cred); |
1732 | |
1733 | |
1734 | set_security_token(p); |
1735 | } |
1736 | |
1737 | return (0); |
1738 | } |
1739 | |
1740 | |
1741 | /* |
1742 | * initgroups |
1743 | * |
1744 | * Description: Initialize the default supplementary groups list and set the |
1745 | * gmuid for use by the external group resolver (if any) |
1746 | * |
1747 | * Parameters: uap->gidsetsize Number of groups in set |
1748 | * uap->gidset Pointer to group list |
1749 | * uap->gmuid Base gid |
1750 | * |
1751 | * Returns: 0 Success |
1752 | * setgroups1:EPERM Permision denied |
1753 | * setgroups1:EINVAL Invalid gidsetsize value |
1754 | * setgroups1:EFAULT Bad gidset or gidsetsize is |
1755 | * |
1756 | * Notes: This function opts *IN* to memberd participation |
1757 | * |
1758 | * The normal purpose of this function is for a privileged |
1759 | * process to indicate supplementary groups and identity for |
1760 | * participation in extended group membership resolution prior |
1761 | * to dropping privilege by assuming a specific user identity. |
1762 | * |
1763 | * It is the first half of the primary mechanism whereby user |
1764 | * identity is established to the system by programs such as |
1765 | * /usr/bin/login. The second half is the drop of uid privilege |
1766 | * for a specific uid corresponding to the user. |
1767 | * |
1768 | * See also: setgroups1() |
1769 | */ |
1770 | int |
1771 | initgroups(proc_t p, struct initgroups_args *uap, __unused int32_t *retval) |
1772 | { |
1773 | DEBUG_CRED_ENTER("initgroups\n" ); |
1774 | |
1775 | return(setgroups1(p, uap->gidsetsize, uap->gidset, uap->gmuid, retval)); |
1776 | } |
1777 | |
1778 | |
1779 | /* |
1780 | * setgroups |
1781 | * |
1782 | * Description: Initialize the default supplementary groups list |
1783 | * |
1784 | * Parameters: gidsetsize Number of groups in set |
1785 | * gidset Pointer to group list |
1786 | * |
1787 | * Returns: 0 Success |
1788 | * setgroups1:EPERM Permision denied |
1789 | * setgroups1:EINVAL Invalid gidsetsize value |
1790 | * setgroups1:EFAULT Bad gidset or gidsetsize is |
1791 | * |
1792 | * Notes: This functions opts *OUT* of memberd participation. |
1793 | * |
1794 | * This function exists for compatibility with POSIX. Most user |
1795 | * programs should use initgroups() instead to ensure correct |
1796 | * participation in group membership resolution when utilizing |
1797 | * a directory service for authentication. |
1798 | * |
1799 | * It is identical to an initgroups() call with a gmuid argument |
1800 | * of KAUTH_UID_NONE. |
1801 | * |
1802 | * See also: setgroups1() |
1803 | */ |
1804 | int |
1805 | setgroups(proc_t p, struct setgroups_args *uap, __unused int32_t *retval) |
1806 | { |
1807 | DEBUG_CRED_ENTER("setgroups\n" ); |
1808 | |
1809 | return(setgroups1(p, uap->gidsetsize, uap->gidset, KAUTH_UID_NONE, retval)); |
1810 | } |
1811 | |
1812 | |
1813 | /* |
1814 | * Set the per-thread/per-process supplementary groups list. |
1815 | * |
1816 | * XXX implement setsgroups |
1817 | * |
1818 | */ |
1819 | |
1820 | int |
1821 | setsgroups(__unused proc_t p, __unused struct setsgroups_args *uap, __unused int32_t *retval) |
1822 | { |
1823 | return(ENOTSUP); |
1824 | } |
1825 | |
1826 | /* |
1827 | * Set the per-thread/per-process whiteout groups list. |
1828 | * |
1829 | * XXX implement setwgroups |
1830 | * |
1831 | */ |
1832 | |
1833 | int |
1834 | setwgroups(__unused proc_t p, __unused struct setwgroups_args *uap, __unused int32_t *retval) |
1835 | { |
1836 | return(ENOTSUP); |
1837 | } |
1838 | |
1839 | |
1840 | /* |
1841 | * Check if gid is a member of the group set. |
1842 | * |
1843 | * XXX This interface is going away; use kauth_cred_ismember_gid() directly |
1844 | * XXX instead. |
1845 | */ |
1846 | int |
1847 | groupmember(gid_t gid, kauth_cred_t cred) |
1848 | { |
1849 | int is_member; |
1850 | |
1851 | if (kauth_cred_ismember_gid(cred, gid, &is_member) == 0 && is_member) |
1852 | return (1); |
1853 | return (0); |
1854 | } |
1855 | |
1856 | |
1857 | /* |
1858 | * Test whether the specified credentials imply "super-user" |
1859 | * privilege; if so, and we have accounting info, set the flag |
1860 | * indicating use of super-powers. |
1861 | * Returns 0 or error. |
1862 | * |
1863 | * XXX This interface is going away; use kauth_cred_issuser() directly |
1864 | * XXX instead. |
1865 | * |
1866 | * Note: This interface exists to implement the "has used privilege" |
1867 | * bit (ASU) in the p_acflags field of the process, which is |
1868 | * only externalized via private sysctl and in process accounting |
1869 | * records. The flag is technically not required in either case. |
1870 | */ |
1871 | int |
1872 | suser(kauth_cred_t cred, u_short *acflag) |
1873 | { |
1874 | #if DIAGNOSTIC |
1875 | if (!IS_VALID_CRED(cred)) |
1876 | panic("suser" ); |
1877 | #endif |
1878 | if (kauth_cred_getuid(cred) == 0) { |
1879 | if (acflag) |
1880 | *acflag |= ASU; |
1881 | return (0); |
1882 | } |
1883 | return (EPERM); |
1884 | } |
1885 | |
1886 | |
1887 | /* |
1888 | * getlogin |
1889 | * |
1890 | * Description: Get login name, if available. |
1891 | * |
1892 | * Parameters: uap->namebuf User buffer for return |
1893 | * uap->namelen User buffer length |
1894 | * |
1895 | * Returns: 0 Success |
1896 | * copyout:EFAULT |
1897 | * |
1898 | * Notes: Intended to obtain a string containing the user name of the |
1899 | * user associated with the controlling terminal for the calling |
1900 | * process. |
1901 | * |
1902 | * Not very useful on modern systems, due to inherent length |
1903 | * limitations for the static array in the session structure |
1904 | * which is used to store the login name. |
1905 | * |
1906 | * Permitted to return NULL |
1907 | * |
1908 | * XXX: Belongs in kern_proc.c |
1909 | */ |
1910 | int |
1911 | getlogin(proc_t p, struct getlogin_args *uap, __unused int32_t *retval) |
1912 | { |
1913 | char buffer[MAXLOGNAME+1]; |
1914 | struct session * sessp; |
1915 | |
1916 | bzero(buffer, MAXLOGNAME+1); |
1917 | |
1918 | sessp = proc_session(p); |
1919 | |
1920 | if (uap->namelen > MAXLOGNAME) |
1921 | uap->namelen = MAXLOGNAME; |
1922 | |
1923 | if(sessp != SESSION_NULL) { |
1924 | session_lock(sessp); |
1925 | bcopy( sessp->s_login, buffer, uap->namelen); |
1926 | session_unlock(sessp); |
1927 | } |
1928 | session_rele(sessp); |
1929 | |
1930 | return (copyout((caddr_t)buffer, uap->namebuf, uap->namelen)); |
1931 | } |
1932 | |
1933 | |
1934 | /* |
1935 | * setlogin |
1936 | * |
1937 | * Description: Set login name. |
1938 | * |
1939 | * Parameters: uap->namebuf User buffer containing name |
1940 | * |
1941 | * Returns: 0 Success |
1942 | * suser:EPERM Permission denied |
1943 | * copyinstr:EFAULT User buffer invalid |
1944 | * copyinstr:EINVAL Supplied name was too long |
1945 | * |
1946 | * Notes: This is a utility system call to support getlogin(). |
1947 | * |
1948 | * XXX: Belongs in kern_proc.c |
1949 | */ |
1950 | int |
1951 | setlogin(proc_t p, struct setlogin_args *uap, __unused int32_t *retval) |
1952 | { |
1953 | int error; |
1954 | size_t dummy=0; |
1955 | char buffer[MAXLOGNAME+1]; |
1956 | struct session * sessp; |
1957 | |
1958 | if ((error = proc_suser(p))) |
1959 | return (error); |
1960 | |
1961 | bzero(&buffer[0], MAXLOGNAME+1); |
1962 | |
1963 | |
1964 | error = copyinstr(uap->namebuf, |
1965 | (caddr_t) &buffer[0], |
1966 | MAXLOGNAME - 1, (size_t *)&dummy); |
1967 | |
1968 | sessp = proc_session(p); |
1969 | |
1970 | if (sessp != SESSION_NULL) { |
1971 | session_lock(sessp); |
1972 | bcopy(buffer, sessp->s_login, MAXLOGNAME); |
1973 | session_unlock(sessp); |
1974 | session_rele(sessp); |
1975 | } |
1976 | |
1977 | |
1978 | if (!error) { |
1979 | AUDIT_ARG(text, buffer); |
1980 | } else if (error == ENAMETOOLONG) |
1981 | error = EINVAL; |
1982 | return (error); |
1983 | } |
1984 | |
1985 | |
1986 | /* Set the secrity token of the task with current euid and eguid */ |
1987 | /* |
1988 | * XXX This needs to change to give the task a reference and/or an opaque |
1989 | * XXX identifier. |
1990 | */ |
1991 | int |
1992 | set_security_token(proc_t p) |
1993 | { |
1994 | return set_security_token_task_internal(p, p->task); |
1995 | } |
1996 | |
1997 | /* |
1998 | * Set the secrity token of the task with current euid and eguid |
1999 | * The function takes a proc and a task, where proc->task might point to a |
2000 | * different task if called from exec. |
2001 | */ |
2002 | |
2003 | int |
2004 | set_security_token_task_internal(proc_t p, void *t) |
2005 | { |
2006 | security_token_t sec_token; |
2007 | audit_token_t audit_token; |
2008 | kauth_cred_t my_cred; |
2009 | posix_cred_t my_pcred; |
2010 | host_priv_t host_priv; |
2011 | task_t task = t; |
2012 | |
2013 | /* |
2014 | * Don't allow a vfork child to override the parent's token settings |
2015 | * (since they share a task). Instead, the child will just have to |
2016 | * suffer along using the parent's token until the exec(). It's all |
2017 | * undefined behavior anyway, right? |
2018 | */ |
2019 | if (task == current_task()) { |
2020 | uthread_t uthread; |
2021 | uthread = (uthread_t)get_bsdthread_info(current_thread()); |
2022 | if (uthread->uu_flag & UT_VFORK) |
2023 | return (1); |
2024 | } |
2025 | |
2026 | my_cred = kauth_cred_proc_ref(p); |
2027 | my_pcred = posix_cred_get(my_cred); |
2028 | |
2029 | /* XXX mach_init doesn't have a p_ucred when it calls this function */ |
2030 | if (IS_VALID_CRED(my_cred)) { |
2031 | sec_token.val[0] = kauth_cred_getuid(my_cred); |
2032 | sec_token.val[1] = kauth_cred_getgid(my_cred); |
2033 | } else { |
2034 | sec_token.val[0] = 0; |
2035 | sec_token.val[1] = 0; |
2036 | } |
2037 | |
2038 | /* |
2039 | * The current layout of the Mach audit token explicitly |
2040 | * adds these fields. But nobody should rely on such |
2041 | * a literal representation. Instead, the BSM library |
2042 | * provides a function to convert an audit token into |
2043 | * a BSM subject. Use of that mechanism will isolate |
2044 | * the user of the trailer from future representation |
2045 | * changes. |
2046 | */ |
2047 | audit_token.val[0] = my_cred->cr_audit.as_aia_p->ai_auid; |
2048 | audit_token.val[1] = my_pcred->cr_uid; |
2049 | audit_token.val[2] = my_pcred->cr_gid; |
2050 | audit_token.val[3] = my_pcred->cr_ruid; |
2051 | audit_token.val[4] = my_pcred->cr_rgid; |
2052 | audit_token.val[5] = p->p_pid; |
2053 | audit_token.val[6] = my_cred->cr_audit.as_aia_p->ai_asid; |
2054 | audit_token.val[7] = p->p_idversion; |
2055 | |
2056 | host_priv = (sec_token.val[0]) ? HOST_PRIV_NULL : host_priv_self(); |
2057 | #if CONFIG_MACF |
2058 | if (host_priv != HOST_PRIV_NULL && mac_system_check_host_priv(my_cred)) |
2059 | host_priv = HOST_PRIV_NULL; |
2060 | #endif |
2061 | kauth_cred_unref(&my_cred); |
2062 | |
2063 | #if DEVELOPMENT || DEBUG |
2064 | /* |
2065 | * Update the pid an proc name for importance base if any |
2066 | */ |
2067 | task_importance_update_owner_info(task); |
2068 | #endif |
2069 | |
2070 | return (host_security_set_task_token(host_security_self(), |
2071 | task, |
2072 | sec_token, |
2073 | audit_token, |
2074 | host_priv) != KERN_SUCCESS); |
2075 | } |
2076 | |
2077 | |
2078 | int get_audit_token_pid(audit_token_t *audit_token); |
2079 | |
2080 | int |
2081 | get_audit_token_pid(audit_token_t *audit_token) |
2082 | { |
2083 | /* keep in-sync with set_security_token (above) */ |
2084 | if (audit_token) |
2085 | return (int)audit_token->val[5]; |
2086 | return -1; |
2087 | } |
2088 | |
2089 | |
2090 | /* |
2091 | * Fill in a struct xucred based on a kauth_cred_t. |
2092 | */ |
2093 | __private_extern__ |
2094 | void |
2095 | cru2x(kauth_cred_t cr, struct xucred *xcr) |
2096 | { |
2097 | posix_cred_t pcr = posix_cred_get(cr); |
2098 | |
2099 | bzero(xcr, sizeof(*xcr)); |
2100 | xcr->cr_version = XUCRED_VERSION; |
2101 | xcr->cr_uid = kauth_cred_getuid(cr); |
2102 | xcr->cr_ngroups = pcr->cr_ngroups; |
2103 | bcopy(pcr->cr_groups, xcr->cr_groups, sizeof(xcr->cr_groups)); |
2104 | } |
2105 | |