1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2010 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /*
27 * Privilege implementation.
28 *
29 * This file provides the infrastructure for privilege sets and limits
30 * the number of files that requires to include <sys/cred_impl.h> and/or
31 * <sys/priv_impl.h>.
32 *
33 * The Solaris privilege mechanism has been designed in a
34 * future proof manner. While the kernel may use fixed size arrays
35 * and fixed bitmasks and bit values, the representation of those
36 * is kernel private. All external interfaces as well as K-to-K interfaces
37 * have been constructed in a manner to provide the maximum flexibility.
38 *
39 * There can be X privilege sets each containing Y 32 bit words.
40 * <X, Y> are constant for a kernel invocation.
41 *
42 * As a consequence, all privilege set manipulation happens in functions
43 * below.
44 *
45 */
46
47 #include <sys/systm.h>
48 #include <sys/ddi.h>
49 #include <sys/kmem.h>
50 #include <sys/sunddi.h>
51 #include <sys/errno.h>
52 #include <sys/debug.h>
53 #include <sys/priv_impl.h>
54 #include <sys/procfs.h>
55 #include <sys/policy.h>
56 #include <sys/cred_impl.h>
57 #include <sys/devpolicy.h>
58 #include <sys/atomic.h>
59
60 /*
61 * Privilege name to number mapping table consists in the generated
62 * priv_const.c file. This lock protects against updates of the privilege
63 * names and counts; all other priv_info fields are read-only.
64 * The actual protected values are:
65 * global variable nprivs
66 * the priv_max field
67 * the priv_names field
68 * the priv names info item (cnt/strings)
69 */
70 krwlock_t privinfo_lock;
71
72 static boolean_t priv_valid(const cred_t *);
73
74 priv_set_t priv_fullset; /* set of all privileges */
75 priv_set_t priv_unsafe; /* unsafe to exec set-uid root if these are not in L */
76
77 /*
78 * Privilege initialization functions.
79 * Called from common/os/cred.c when cred_init is called.
80 */
81
82 void
priv_init(void)83 priv_init(void)
84 {
85 #ifdef DEBUG
86 int alloc_test_priv = 1;
87 #else
88 int alloc_test_priv = priv_debug;
89 #endif
90 rw_init(&privinfo_lock, NULL, RW_DRIVER, NULL);
91
92 PRIV_BASIC_ASSERT(priv_basic);
93 PRIV_UNSAFE_ASSERT(&priv_unsafe);
94 priv_fillset(&priv_fullset);
95
96 /*
97 * When booting with priv_debug set or in a DEBUG kernel, then we'll
98 * add an additional basic privilege and we verify that it is always
99 * present in E.
100 */
101 if (alloc_test_priv != 0 &&
102 (priv_basic_test = priv_getbyname("basic_test", PRIV_ALLOC)) >= 0) {
103 priv_addset(priv_basic, priv_basic_test);
104 }
105
106 devpolicy_init();
107 }
108
109 /* Utility functions: privilege sets as opaque data types */
110
111 /*
112 * Guts of prgetprivsize.
113 */
114 int
priv_prgetprivsize(prpriv_t * tmpl)115 priv_prgetprivsize(prpriv_t *tmpl)
116 {
117 return (sizeof (prpriv_t) +
118 PRIV_SETBYTES - sizeof (priv_chunk_t) +
119 (tmpl ? tmpl->pr_infosize : priv_info->priv_infosize));
120 }
121
122 /*
123 * Guts of prgetpriv.
124 */
125 void
cred2prpriv(const cred_t * cp,prpriv_t * pr)126 cred2prpriv(const cred_t *cp, prpriv_t *pr)
127 {
128 priv_set_t *psa;
129 int i;
130
131 pr->pr_nsets = PRIV_NSET;
132 pr->pr_setsize = PRIV_SETSIZE;
133 pr->pr_infosize = priv_info->priv_infosize;
134
135 psa = (priv_set_t *)pr->pr_sets;
136
137 for (i = 0; i < PRIV_NSET; i++)
138 psa[i] = *priv_getset(cp, i);
139
140 priv_getinfo(cp, (char *)pr + PRIV_PRPRIV_INFO_OFFSET(pr));
141 }
142
143 /*
144 * Guts of pr_spriv:
145 *
146 * Set the privileges of a process.
147 *
148 * In order to set the privileges, the setting process will need to
149 * have those privileges in its effective set in order to prevent
150 * specially privileged processes to easily gain additional privileges.
151 * Pre-existing privileges can be retained. To change any privileges,
152 * PRIV_PROC_OWNER needs to be asserted.
153 *
154 * In formula:
155 *
156 * S' <= S || S' <= S + Ea
157 *
158 * the new set must either be subset of the old set or a subset of
159 * the oldset merged with the effective set of the acting process; or just:
160 *
161 * S' <= S + Ea
162 *
163 * It's not legal to grow the limit set this way.
164 *
165 */
166 int
priv_pr_spriv(proc_t * p,prpriv_t * prpriv,const cred_t * cr)167 priv_pr_spriv(proc_t *p, prpriv_t *prpriv, const cred_t *cr)
168 {
169 cred_t *oldcred;
170 cred_t *newcred;
171 int i;
172 int err = EPERM;
173 cred_priv_t *cp, *ocp;
174 priv_set_t eset;
175
176 ASSERT(MUTEX_HELD(&p->p_lock));
177
178 /*
179 * Set must have proper dimension; infosize must be absent
180 * or properly sized.
181 */
182 if (prpriv->pr_nsets != PRIV_NSET ||
183 prpriv->pr_setsize != PRIV_SETSIZE ||
184 (prpriv->pr_infosize & (sizeof (uint32_t) - 1)) != 0 ||
185 prpriv->pr_infosize > priv_info->priv_infosize ||
186 prpriv->pr_infosize < 0)
187 return (EINVAL);
188
189 mutex_exit(&p->p_lock);
190
191 if (priv_proc_cred_perm(cr, p, &oldcred, VWRITE) != 0) {
192 mutex_enter(&p->p_lock);
193 return (EPERM);
194 }
195
196 newcred = crdup(oldcred);
197
198 /* Copy the privilege sets from prpriv to newcred */
199 bcopy(prpriv->pr_sets, CR_PRIVSETS(newcred), PRIV_SETBYTES);
200
201 cp = &newcred->cr_priv;
202 ocp = &oldcred->cr_priv;
203 eset = CR_OEPRIV(cr);
204
205 priv_intersect(&CR_LPRIV(oldcred), &eset);
206
207 /*
208 * Verify the constraints laid out:
209 * for the limit set, we require that the new set is a subset
210 * of the old limit set.
211 * for all other sets, we require that the new set is either a
212 * subset of the old set or a subset of the intersection of
213 * the old limit set and the effective set of the acting process.
214 */
215 for (i = 0; i < PRIV_NSET; i++)
216 if (!priv_issubset(&cp->crprivs[i], &ocp->crprivs[i]) &&
217 (i == PRIV_LIMIT || !priv_issubset(&cp->crprivs[i], &eset)))
218 break;
219
220 crfree(oldcred);
221
222 if (i < PRIV_NSET || !priv_valid(newcred))
223 goto err;
224
225 /* Load the settable privilege information */
226 if (prpriv->pr_infosize > 0) {
227 char *x = (char *)prpriv + PRIV_PRPRIV_INFO_OFFSET(prpriv);
228 char *lastx = x + prpriv->pr_infosize;
229
230 while (x < lastx) {
231 priv_info_t *pi = (priv_info_t *)x;
232 priv_info_uint_t *pii;
233
234 switch (pi->priv_info_type) {
235 case PRIV_INFO_FLAGS:
236 pii = (priv_info_uint_t *)x;
237 if (pii->info.priv_info_size != sizeof (*pii)) {
238 err = EINVAL;
239 goto err;
240 }
241 CR_FLAGS(newcred) &= ~PRIV_USER;
242 CR_FLAGS(newcred) |= (pii->val & PRIV_USER);
243 break;
244 default:
245 err = EINVAL;
246 goto err;
247 }
248 /* Guarantee alignment and forward progress */
249 if ((pi->priv_info_size & (sizeof (uint32_t) - 1)) ||
250 pi->priv_info_size < sizeof (*pi) ||
251 lastx - x > pi->priv_info_size) {
252 err = EINVAL;
253 goto err;
254 }
255
256 x += pi->priv_info_size;
257 }
258 }
259
260 /*
261 * We'll try to copy the privilege aware flag; but since the
262 * privileges sets are all individually set, they are set
263 * as if we're privilege aware. If PRIV_AWARE wasn't set
264 * or was explicitely unset, we need to set the flag and then
265 * try to get rid of it.
266 */
267 if ((CR_FLAGS(newcred) & PRIV_AWARE) == 0) {
268 CR_FLAGS(newcred) |= PRIV_AWARE;
269 priv_adjust_PA(newcred);
270 }
271
272 mutex_enter(&p->p_crlock);
273 oldcred = p->p_cred;
274 p->p_cred = newcred;
275 mutex_exit(&p->p_crlock);
276 crfree(oldcred);
277
278 mutex_enter(&p->p_lock);
279 return (0);
280
281 err:
282 crfree(newcred);
283 mutex_enter(&p->p_lock);
284 return (err);
285 }
286
287 priv_impl_info_t
priv_hold_implinfo(void)288 *priv_hold_implinfo(void)
289 {
290 rw_enter(&privinfo_lock, RW_READER);
291 return (priv_info);
292 }
293
294 void
priv_release_implinfo(void)295 priv_release_implinfo(void)
296 {
297 rw_exit(&privinfo_lock);
298 }
299
300 size_t
priv_get_implinfo_size(void)301 priv_get_implinfo_size(void)
302 {
303 return (privinfosize);
304 }
305
306
307 /*
308 * Return the nth privilege set
309 */
310 const priv_set_t *
priv_getset(const cred_t * cr,int set)311 priv_getset(const cred_t *cr, int set)
312 {
313 ASSERT(PRIV_VALIDSET(set));
314
315 if ((CR_FLAGS(cr) & PRIV_AWARE) == 0)
316 switch (set) {
317 case PRIV_EFFECTIVE:
318 return (&CR_OEPRIV(cr));
319 case PRIV_PERMITTED:
320 return (&CR_OPPRIV(cr));
321 }
322 return (&CR_PRIVS(cr)->crprivs[set]);
323 }
324
325 /*
326 * Buf must be allocated by caller and contain sufficient space to
327 * contain all additional info structures using priv_info.priv_infosize.
328 * The buffer must be properly aligned.
329 */
330 /*ARGSUSED*/
331 void
priv_getinfo(const cred_t * cr,void * buf)332 priv_getinfo(const cred_t *cr, void *buf)
333 {
334 struct priv_info_uint *ii;
335
336 ii = buf;
337 ii->val = CR_FLAGS(cr);
338 ii->info.priv_info_size = (uint32_t)sizeof (*ii);
339 ii->info.priv_info_type = PRIV_INFO_FLAGS;
340 }
341
342 int
priv_getbyname(const char * name,uint_t flag)343 priv_getbyname(const char *name, uint_t flag)
344 {
345 int i;
346 int wheld = 0;
347 int len;
348 char *p;
349
350 if (flag != 0 && flag != PRIV_ALLOC)
351 return (-EINVAL);
352
353 if (strncasecmp(name, "priv_", 5) == 0)
354 name += 5;
355
356 rw_enter(&privinfo_lock, RW_READER);
357 rescan:
358 for (i = 0; i < nprivs; i++)
359 if (strcasecmp(priv_names[i], name) == 0) {
360 rw_exit(&privinfo_lock);
361 return (i);
362 }
363
364
365 if (!wheld) {
366 if (!(flag & PRIV_ALLOC)) {
367 rw_exit(&privinfo_lock);
368 return (-EINVAL);
369 }
370
371 /* check length, validity and available space */
372 len = strlen(name) + 1;
373
374 if (len > PRIVNAME_MAX) {
375 rw_exit(&privinfo_lock);
376 return (-ENAMETOOLONG);
377 }
378
379 for (p = (char *)name; *p != '\0'; p++) {
380 char c = *p;
381
382 if (!((c >= 'A' && c <= 'Z') ||
383 (c >= 'a' && c <= 'z') ||
384 (c >= '0' && c <= '9') ||
385 c == '_')) {
386 rw_exit(&privinfo_lock);
387 return (-EINVAL);
388 }
389 }
390
391 if (!rw_tryupgrade(&privinfo_lock)) {
392 rw_exit(&privinfo_lock);
393 rw_enter(&privinfo_lock, RW_WRITER);
394 wheld = 1;
395 /* Someone may have added our privilege */
396 goto rescan;
397 }
398 }
399
400 if (nprivs == MAX_PRIVILEGE || len + privbytes > maxprivbytes) {
401 rw_exit(&privinfo_lock);
402 return (-ENOMEM);
403 }
404
405 priv_names[i] = p = priv_str + privbytes;
406
407 bcopy(name, p, len);
408
409 /* make the priv_names[i] and privilege name globally visible */
410 membar_producer();
411
412 /* adjust priv count and bytes count */
413 priv_ninfo->cnt = priv_info->priv_max = ++nprivs;
414 privbytes += len;
415
416 rw_exit(&privinfo_lock);
417 return (i);
418 }
419
420 /*
421 * We can't afford locking the privileges here because of the locations
422 * we call this from; so we make sure that the privileges table
423 * is visible to us; it is made visible before the value of nprivs is
424 * updated.
425 */
426 const char *
priv_getbynum(int priv)427 priv_getbynum(int priv)
428 {
429 int maxpriv = nprivs;
430
431 membar_consumer();
432
433 if (priv >= 0 && priv < maxpriv)
434 return (priv_names[priv]);
435
436 return (NULL);
437 }
438
439 const char *
priv_getsetbynum(int setno)440 priv_getsetbynum(int setno)
441 {
442 if (!PRIV_VALIDSET(setno))
443 return (NULL);
444
445 return (priv_setnames[setno]);
446 }
447
448 /*
449 * Privilege sanity checking when setting: E <= P.
450 */
451 static boolean_t
priv_valid(const cred_t * cr)452 priv_valid(const cred_t *cr)
453 {
454 return (priv_issubset(&CR_EPRIV(cr), &CR_PPRIV(cr)));
455 }
456
457 /*
458 * Privilege manipulation functions
459 *
460 * Without knowing the details of the privilege set implementation,
461 * opaque pointers can be used to manipulate sets at will.
462 */
463 void
priv_emptyset(priv_set_t * set)464 priv_emptyset(priv_set_t *set)
465 {
466 bzero(set, sizeof (*set));
467 }
468
469 void
priv_fillset(priv_set_t * set)470 priv_fillset(priv_set_t *set)
471 {
472 int i;
473
474 /* memset? */
475 for (i = 0; i < PRIV_SETSIZE; i++)
476 set->pbits[i] = ~(priv_chunk_t)0;
477 }
478
479 void
priv_addset(priv_set_t * set,int priv)480 priv_addset(priv_set_t *set, int priv)
481 {
482 ASSERT(priv >= 0 && priv < MAX_PRIVILEGE);
483 __PRIV_ASSERT(set, priv);
484 }
485
486 void
priv_delset(priv_set_t * set,int priv)487 priv_delset(priv_set_t *set, int priv)
488 {
489 ASSERT(priv >= 0 && priv < MAX_PRIVILEGE);
490 __PRIV_CLEAR(set, priv);
491 }
492
493 boolean_t
priv_ismember(const priv_set_t * set,int priv)494 priv_ismember(const priv_set_t *set, int priv)
495 {
496 ASSERT(priv >= 0 && priv < MAX_PRIVILEGE);
497 return (__PRIV_ISASSERT(set, priv) ? B_TRUE : B_FALSE);
498 }
499
500 #define PRIV_TEST_BODY(test) \
501 int i; \
502 \
503 for (i = 0; i < PRIV_SETSIZE; i++) \
504 if (!(test)) \
505 return (B_FALSE); \
506 \
507 return (B_TRUE)
508
509 boolean_t
priv_isequalset(const priv_set_t * a,const priv_set_t * b)510 priv_isequalset(const priv_set_t *a, const priv_set_t *b)
511 {
512 return ((boolean_t)(bcmp(a, b, sizeof (*a)) == 0));
513 }
514
515 boolean_t
priv_isemptyset(const priv_set_t * set)516 priv_isemptyset(const priv_set_t *set)
517 {
518 PRIV_TEST_BODY(set->pbits[i] == 0);
519 }
520
521 boolean_t
priv_isfullset(const priv_set_t * set)522 priv_isfullset(const priv_set_t *set)
523 {
524 PRIV_TEST_BODY(set->pbits[i] == ~(priv_chunk_t)0);
525 }
526
527 /*
528 * Return true if a is a subset of b
529 */
530 boolean_t
priv_issubset(const priv_set_t * a,const priv_set_t * b)531 priv_issubset(const priv_set_t *a, const priv_set_t *b)
532 {
533 PRIV_TEST_BODY((a->pbits[i] | b->pbits[i]) == b->pbits[i]);
534 }
535
536 #define PRIV_CHANGE_BODY(a, op, b) \
537 int i; \
538 \
539 for (i = 0; i < PRIV_SETSIZE; i++) \
540 a->pbits[i] op b->pbits[i]
541
542 /* B = A ^ B */
543 void
priv_intersect(const priv_set_t * a,priv_set_t * b)544 priv_intersect(const priv_set_t *a, priv_set_t *b)
545 {
546 /* CSTYLED */
547 PRIV_CHANGE_BODY(b, &=, a);
548 }
549
550 /* B = A v B */
551 void
priv_union(const priv_set_t * a,priv_set_t * b)552 priv_union(const priv_set_t *a, priv_set_t *b)
553 {
554 /* CSTYLED */
555 PRIV_CHANGE_BODY(b, |=, a);
556 }
557
558 /* A = ! A */
559 void
priv_inverse(priv_set_t * a)560 priv_inverse(priv_set_t *a)
561 {
562 PRIV_CHANGE_BODY(a, = ~, a);
563 }
564
565 /*
566 * Can the source cred act on the target credential?
567 *
568 * We will you allow to gain uids this way but not privileges.
569 */
570 int
priv_proc_cred_perm(const cred_t * scr,proc_t * tp,cred_t ** pcr,int mode)571 priv_proc_cred_perm(const cred_t *scr, proc_t *tp, cred_t **pcr, int mode)
572 {
573 const priv_set_t *eset;
574 int idsmatch;
575 cred_t *tcr;
576 int res = 0;
577
578 /* prevent the cred from going away */
579 mutex_enter(&tp->p_crlock);
580 crhold(tcr = tp->p_cred);
581 mutex_exit(&tp->p_crlock);
582
583 if (scr == tcr && !(tp->p_flag & SNOCD))
584 goto out;
585
586 idsmatch = (scr->cr_uid == tcr->cr_uid &&
587 scr->cr_uid == tcr->cr_ruid &&
588 scr->cr_uid == tcr->cr_suid &&
589 scr->cr_gid == tcr->cr_gid &&
590 scr->cr_gid == tcr->cr_rgid &&
591 scr->cr_gid == tcr->cr_sgid &&
592 !(tp->p_flag & SNOCD));
593
594 /*
595 * Source credential must have the proc_zone privilege if referencing
596 * a process in another zone.
597 */
598 if (scr->cr_zone != tcr->cr_zone && secpolicy_proc_zone(scr) != 0) {
599 res = EACCES;
600 goto out;
601 }
602
603 if (!(mode & VWRITE)) {
604 if (!idsmatch && secpolicy_proc_owner(scr, tcr, 0) != 0)
605 res = EACCES;
606 goto out;
607 }
608
609 /*
610 * For writing, the effective set of scr must dominate all sets of tcr,
611 * We test Pt <= Es (Et <= Pt so no need to test) and It <= Es
612 * The Limit set of scr must be a superset of the limitset of
613 * tcr.
614 */
615 eset = &CR_OEPRIV(scr);
616
617 if (!priv_issubset(&CR_IPRIV(tcr), eset) ||
618 !priv_issubset(&CR_OPPRIV(tcr), eset) ||
619 !priv_issubset(&CR_LPRIV(tcr), &CR_LPRIV(scr)) ||
620 !idsmatch && secpolicy_proc_owner(scr, tcr, mode) != 0)
621 res = EACCES;
622
623 out:
624 if (res == 0 && pcr != NULL)
625 *pcr = tcr;
626 else
627 crfree(tcr);
628 return (res);
629 }
630
631 /*
632 * Set the privilege aware bit, adding L to E/P if necessary.
633 * Each time we set it, we also clear PRIV_AWARE_RESET.
634 */
635 void
priv_set_PA(cred_t * cr)636 priv_set_PA(cred_t *cr)
637 {
638 ASSERT(cr->cr_ref <= 2);
639
640 if ((CR_FLAGS(cr) & (PRIV_AWARE|PRIV_AWARE_RESET)) == PRIV_AWARE)
641 return;
642
643 CR_FLAGS(cr) |= PRIV_AWARE;
644 CR_FLAGS(cr) &= ~PRIV_AWARE_RESET;
645
646 if (cr->cr_uid == 0)
647 priv_union(&CR_LPRIV(cr), &CR_EPRIV(cr));
648
649 if (cr->cr_uid == 0 || cr->cr_suid == 0 || cr->cr_ruid == 0)
650 priv_union(&CR_LPRIV(cr), &CR_PPRIV(cr));
651 }
652
653 boolean_t
priv_can_clear_PA(const cred_t * cr)654 priv_can_clear_PA(const cred_t *cr)
655 {
656 /*
657 * We can clear PA in the following cases:
658 *
659 * None of the uids are 0.
660 * Any uid == 0 and P == L and (Euid != 0 or E == L)
661 */
662 return ((cr->cr_suid != 0 && cr->cr_ruid != 0 && cr->cr_uid != 0) ||
663 priv_isequalset(&CR_PPRIV(cr), &CR_LPRIV(cr)) &&
664 (cr->cr_uid != 0 || priv_isequalset(&CR_EPRIV(cr), &CR_LPRIV(cr))));
665 }
666
667 /*
668 * Clear privilege aware bit if it is an idempotent operation and by
669 * clearing it the process cannot get to uid 0 and all privileges.
670 *
671 * This function should be called with caution as it may cause "E" to be
672 * lost once a processes assumes euid 0 again.
673 */
674 void
priv_adjust_PA(cred_t * cr)675 priv_adjust_PA(cred_t *cr)
676 {
677 ASSERT(cr->cr_ref <= 2);
678
679 if (!(CR_FLAGS(cr) & PRIV_AWARE) ||
680 !priv_can_clear_PA(cr)) {
681 CR_FLAGS(cr) &= ~PRIV_AWARE_RESET;
682 return;
683 }
684
685 if (CR_FLAGS(cr) & PRIV_AWARE_INHERIT)
686 return;
687
688 /*
689 * We now need to adjust P/E in those cases when uids
690 * are zero; the rules are P' = I & L, E' = I & L;
691 * but since P = L and E = L, we can use P &= I, E &= I,
692 * depending on which uids are 0.
693 */
694 if (cr->cr_suid == 0 || cr->cr_ruid == 0 || cr->cr_uid == 0) {
695 if (cr->cr_uid == 0)
696 priv_intersect(&CR_IPRIV(cr), &CR_EPRIV(cr));
697 priv_intersect(&CR_IPRIV(cr), &CR_PPRIV(cr));
698 }
699
700 CR_FLAGS(cr) &= ~(PRIV_AWARE|PRIV_AWARE_RESET);
701 }
702
703 /*
704 * Reset privilege aware bit if so requested by setting the PRIV_AWARE_RESET
705 * flag.
706 */
707 void
priv_reset_PA(cred_t * cr,boolean_t finalize)708 priv_reset_PA(cred_t *cr, boolean_t finalize)
709 {
710 ASSERT(cr->cr_ref <= 2);
711
712 if ((CR_FLAGS(cr) & (PRIV_AWARE|PRIV_AWARE_RESET)) !=
713 (PRIV_AWARE|PRIV_AWARE_RESET)) {
714 CR_FLAGS(cr) &= ~PRIV_AWARE_RESET;
715 return;
716 }
717
718 /*
719 * When PRIV_AWARE_RESET is enabled, any change of uids causes
720 * a change to the P and E sets. Bracketing with
721 * seteuid(0) ... seteuid(uid)/setreuid(-1, 0) .. setreuid(-1, uid)
722 * will cause the privilege sets "do the right thing.".
723 * When the change of the uid is "final", e.g., by using setuid(uid),
724 * or setreuid(uid, uid) or when the last set*uid() call causes all
725 * uids to be the same, we set P and E to I & L, like when you exec.
726 * We make an exception when all the uids are 0; this is required
727 * when we login as root as in that particular case we cannot
728 * make a distinction between seteuid(0) and seteuid(uid).
729 * We rely on seteuid/setreuid/setuid to tell us with the
730 * "finalize" argument that we no longer expect new uid changes,
731 * cf. setreuid(uid, uid) and setuid(uid).
732 */
733 if (cr->cr_suid == cr->cr_ruid && cr->cr_suid == cr->cr_uid) {
734 if (finalize || cr->cr_uid != 0) {
735 CR_EPRIV(cr) = CR_IPRIV(cr);
736 priv_intersect(&CR_LPRIV(cr), &CR_EPRIV(cr));
737 CR_PPRIV(cr) = CR_EPRIV(cr);
738 CR_FLAGS(cr) &= ~(PRIV_AWARE|PRIV_AWARE_RESET);
739 } else {
740 CR_EPRIV(cr) = CR_PPRIV(cr);
741 }
742 } else if (cr->cr_uid != 0 && (cr->cr_ruid == 0 || cr->cr_suid == 0)) {
743 CR_EPRIV(cr) = CR_IPRIV(cr);
744 priv_intersect(&CR_LPRIV(cr), &CR_EPRIV(cr));
745 }
746 }
747