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(const prpriv_t * tmpl)115 priv_prgetprivsize(const 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 return (EINVAL);
187
188 mutex_exit(&p->p_lock);
189
190 if (priv_proc_cred_perm(cr, p, &oldcred, VWRITE) != 0) {
191 mutex_enter(&p->p_lock);
192 return (EPERM);
193 }
194
195 newcred = crdup(oldcred);
196
197 /* Copy the privilege sets from prpriv to newcred */
198 bcopy(prpriv->pr_sets, CR_PRIVSETS(newcred), PRIV_SETBYTES);
199
200 cp = &newcred->cr_priv;
201 ocp = &oldcred->cr_priv;
202 eset = CR_OEPRIV(cr);
203
204 priv_intersect(&CR_LPRIV(oldcred), &eset);
205
206 /*
207 * Verify the constraints laid out:
208 * for the limit set, we require that the new set is a subset
209 * of the old limit set.
210 * for all other sets, we require that the new set is either a
211 * subset of the old set or a subset of the intersection of
212 * the old limit set and the effective set of the acting process.
213 */
214 for (i = 0; i < PRIV_NSET; i++)
215 if (!priv_issubset(&cp->crprivs[i], &ocp->crprivs[i]) &&
216 (i == PRIV_LIMIT || !priv_issubset(&cp->crprivs[i], &eset)))
217 break;
218
219 crfree(oldcred);
220
221 if (i < PRIV_NSET || !priv_valid(newcred))
222 goto err;
223
224 /* Load the settable privilege information */
225 if (prpriv->pr_infosize > 0) {
226 char *x = (char *)prpriv + PRIV_PRPRIV_INFO_OFFSET(prpriv);
227 char *lastx = x + prpriv->pr_infosize;
228
229 while (x < lastx) {
230 priv_info_t *pi = (priv_info_t *)x;
231 priv_info_uint_t *pii;
232
233 switch (pi->priv_info_type) {
234 case PRIV_INFO_FLAGS:
235 pii = (priv_info_uint_t *)x;
236 if (pii->info.priv_info_size != sizeof (*pii)) {
237 err = EINVAL;
238 goto err;
239 }
240 CR_FLAGS(newcred) &= ~PRIV_USER;
241 CR_FLAGS(newcred) |= (pii->val & PRIV_USER);
242 break;
243 default:
244 err = EINVAL;
245 goto err;
246 }
247 /* Guarantee alignment and forward progress */
248 if ((pi->priv_info_size & (sizeof (uint32_t) - 1)) ||
249 pi->priv_info_size < sizeof (*pi) ||
250 lastx - x > pi->priv_info_size) {
251 err = EINVAL;
252 goto err;
253 }
254
255 x += pi->priv_info_size;
256 }
257 }
258
259 /*
260 * We'll try to copy the privilege aware flag; but since the
261 * privileges sets are all individually set, they are set
262 * as if we're privilege aware. If PRIV_AWARE wasn't set
263 * or was explicitely unset, we need to set the flag and then
264 * try to get rid of it.
265 */
266 if ((CR_FLAGS(newcred) & PRIV_AWARE) == 0) {
267 CR_FLAGS(newcred) |= PRIV_AWARE;
268 priv_adjust_PA(newcred);
269 }
270
271 mutex_enter(&p->p_crlock);
272 oldcred = p->p_cred;
273 p->p_cred = newcred;
274 mutex_exit(&p->p_crlock);
275 crfree(oldcred);
276
277 mutex_enter(&p->p_lock);
278 return (0);
279
280 err:
281 crfree(newcred);
282 mutex_enter(&p->p_lock);
283 return (err);
284 }
285
286 priv_impl_info_t
priv_hold_implinfo(void)287 *priv_hold_implinfo(void)
288 {
289 rw_enter(&privinfo_lock, RW_READER);
290 return (priv_info);
291 }
292
293 void
priv_release_implinfo(void)294 priv_release_implinfo(void)
295 {
296 rw_exit(&privinfo_lock);
297 }
298
299 size_t
priv_get_implinfo_size(void)300 priv_get_implinfo_size(void)
301 {
302 return (privinfosize);
303 }
304
305
306 /*
307 * Return the nth privilege set
308 */
309 const priv_set_t *
priv_getset(const cred_t * cr,int set)310 priv_getset(const cred_t *cr, int set)
311 {
312 ASSERT(PRIV_VALIDSET(set));
313
314 if ((CR_FLAGS(cr) & PRIV_AWARE) == 0)
315 switch (set) {
316 case PRIV_EFFECTIVE:
317 return (&CR_OEPRIV(cr));
318 case PRIV_PERMITTED:
319 return (&CR_OPPRIV(cr));
320 }
321 return (&CR_PRIVS(cr)->crprivs[set]);
322 }
323
324 /*
325 * Buf must be allocated by caller and contain sufficient space to
326 * contain all additional info structures using priv_info.priv_infosize.
327 * The buffer must be properly aligned.
328 */
329 /*ARGSUSED*/
330 void
priv_getinfo(const cred_t * cr,void * buf)331 priv_getinfo(const cred_t *cr, void *buf)
332 {
333 struct priv_info_uint *ii;
334
335 ii = buf;
336 ii->val = CR_FLAGS(cr);
337 ii->info.priv_info_size = (uint32_t)sizeof (*ii);
338 ii->info.priv_info_type = PRIV_INFO_FLAGS;
339 }
340
341 int
priv_getbyname(const char * name,uint_t flag)342 priv_getbyname(const char *name, uint_t flag)
343 {
344 int i;
345 int wheld = 0;
346 int len;
347 char *p;
348
349 if (flag != 0 && flag != PRIV_ALLOC)
350 return (-EINVAL);
351
352 if (strncasecmp(name, "priv_", 5) == 0)
353 name += 5;
354
355 rw_enter(&privinfo_lock, RW_READER);
356 rescan:
357 for (i = 0; i < nprivs; i++)
358 if (strcasecmp(priv_names[i], name) == 0) {
359 rw_exit(&privinfo_lock);
360 return (i);
361 }
362
363
364 if (!wheld) {
365 if (!(flag & PRIV_ALLOC)) {
366 rw_exit(&privinfo_lock);
367 return (-EINVAL);
368 }
369
370 /* check length, validity and available space */
371 len = strlen(name) + 1;
372
373 if (len > PRIVNAME_MAX) {
374 rw_exit(&privinfo_lock);
375 return (-ENAMETOOLONG);
376 }
377
378 for (p = (char *)name; *p != '\0'; p++) {
379 char c = *p;
380
381 if (!((c >= 'A' && c <= 'Z') ||
382 (c >= 'a' && c <= 'z') ||
383 (c >= '0' && c <= '9') ||
384 c == '_')) {
385 rw_exit(&privinfo_lock);
386 return (-EINVAL);
387 }
388 }
389
390 if (!rw_tryupgrade(&privinfo_lock)) {
391 rw_exit(&privinfo_lock);
392 rw_enter(&privinfo_lock, RW_WRITER);
393 wheld = 1;
394 /* Someone may have added our privilege */
395 goto rescan;
396 }
397 }
398
399 if (nprivs == MAX_PRIVILEGE || len + privbytes > maxprivbytes) {
400 rw_exit(&privinfo_lock);
401 return (-ENOMEM);
402 }
403
404 priv_names[i] = p = priv_str + privbytes;
405
406 bcopy(name, p, len);
407
408 /* make the priv_names[i] and privilege name globally visible */
409 membar_producer();
410
411 /* adjust priv count and bytes count */
412 priv_ninfo->cnt = priv_info->priv_max = ++nprivs;
413 privbytes += len;
414
415 rw_exit(&privinfo_lock);
416 return (i);
417 }
418
419 /*
420 * We can't afford locking the privileges here because of the locations
421 * we call this from; so we make sure that the privileges table
422 * is visible to us; it is made visible before the value of nprivs is
423 * updated.
424 */
425 const char *
priv_getbynum(int priv)426 priv_getbynum(int priv)
427 {
428 int maxpriv = nprivs;
429
430 membar_consumer();
431
432 if (priv >= 0 && priv < maxpriv)
433 return (priv_names[priv]);
434
435 return (NULL);
436 }
437
438 const char *
priv_getsetbynum(int setno)439 priv_getsetbynum(int setno)
440 {
441 if (!PRIV_VALIDSET(setno))
442 return (NULL);
443
444 return (priv_setnames[setno]);
445 }
446
447 /*
448 * Privilege sanity checking when setting: E <= P.
449 */
450 static boolean_t
priv_valid(const cred_t * cr)451 priv_valid(const cred_t *cr)
452 {
453 return (priv_issubset(&CR_EPRIV(cr), &CR_PPRIV(cr)));
454 }
455
456 /*
457 * Privilege manipulation functions
458 *
459 * Without knowing the details of the privilege set implementation,
460 * opaque pointers can be used to manipulate sets at will.
461 */
462 void
priv_emptyset(priv_set_t * set)463 priv_emptyset(priv_set_t *set)
464 {
465 bzero(set, sizeof (*set));
466 }
467
468 void
priv_fillset(priv_set_t * set)469 priv_fillset(priv_set_t *set)
470 {
471 int i;
472
473 /* memset? */
474 for (i = 0; i < PRIV_SETSIZE; i++)
475 set->pbits[i] = ~(priv_chunk_t)0;
476 }
477
478 void
priv_addset(priv_set_t * set,int priv)479 priv_addset(priv_set_t *set, int priv)
480 {
481 ASSERT(priv >= 0 && priv < MAX_PRIVILEGE);
482 __PRIV_ASSERT(set, priv);
483 }
484
485 void
priv_delset(priv_set_t * set,int priv)486 priv_delset(priv_set_t *set, int priv)
487 {
488 ASSERT(priv >= 0 && priv < MAX_PRIVILEGE);
489 __PRIV_CLEAR(set, priv);
490 }
491
492 boolean_t
priv_ismember(const priv_set_t * set,int priv)493 priv_ismember(const priv_set_t *set, int priv)
494 {
495 ASSERT(priv >= 0 && priv < MAX_PRIVILEGE);
496 return (__PRIV_ISASSERT(set, priv) ? B_TRUE : B_FALSE);
497 }
498
499 #define PRIV_TEST_BODY(test) \
500 int i; \
501 \
502 for (i = 0; i < PRIV_SETSIZE; i++) \
503 if (!(test)) \
504 return (B_FALSE); \
505 \
506 return (B_TRUE)
507
508 boolean_t
priv_isequalset(const priv_set_t * a,const priv_set_t * b)509 priv_isequalset(const priv_set_t *a, const priv_set_t *b)
510 {
511 return ((boolean_t)(bcmp(a, b, sizeof (*a)) == 0));
512 }
513
514 boolean_t
priv_isemptyset(const priv_set_t * set)515 priv_isemptyset(const priv_set_t *set)
516 {
517 PRIV_TEST_BODY(set->pbits[i] == 0);
518 }
519
520 boolean_t
priv_isfullset(const priv_set_t * set)521 priv_isfullset(const priv_set_t *set)
522 {
523 PRIV_TEST_BODY(set->pbits[i] == ~(priv_chunk_t)0);
524 }
525
526 /*
527 * Return true if a is a subset of b
528 */
529 boolean_t
priv_issubset(const priv_set_t * a,const priv_set_t * b)530 priv_issubset(const priv_set_t *a, const priv_set_t *b)
531 {
532 PRIV_TEST_BODY((a->pbits[i] | b->pbits[i]) == b->pbits[i]);
533 }
534
535 #define PRIV_CHANGE_BODY(a, op, b) \
536 int i; \
537 \
538 for (i = 0; i < PRIV_SETSIZE; i++) \
539 a->pbits[i] op b->pbits[i]
540
541 /* B = A ^ B */
542 void
priv_intersect(const priv_set_t * a,priv_set_t * b)543 priv_intersect(const priv_set_t *a, priv_set_t *b)
544 {
545 /* CSTYLED */
546 PRIV_CHANGE_BODY(b, &=, a);
547 }
548
549 /* B = A v B */
550 void
priv_union(const priv_set_t * a,priv_set_t * b)551 priv_union(const priv_set_t *a, priv_set_t *b)
552 {
553 /* CSTYLED */
554 PRIV_CHANGE_BODY(b, |=, a);
555 }
556
557 /* A = ! A */
558 void
priv_inverse(priv_set_t * a)559 priv_inverse(priv_set_t *a)
560 {
561 PRIV_CHANGE_BODY(a, = ~, a);
562 }
563
564 /*
565 * Can the source cred act on the target credential?
566 *
567 * We will you allow to gain uids this way but not privileges.
568 */
569 int
priv_proc_cred_perm(const cred_t * scr,proc_t * tp,cred_t ** pcr,int mode)570 priv_proc_cred_perm(const cred_t *scr, proc_t *tp, cred_t **pcr, int mode)
571 {
572 const priv_set_t *eset;
573 int idsmatch;
574 cred_t *tcr;
575 int res = 0;
576
577 /* prevent the cred from going away */
578 mutex_enter(&tp->p_crlock);
579 crhold(tcr = tp->p_cred);
580 mutex_exit(&tp->p_crlock);
581
582 if (scr == tcr && !(tp->p_flag & SNOCD))
583 goto out;
584
585 idsmatch = (scr->cr_uid == tcr->cr_uid &&
586 scr->cr_uid == tcr->cr_ruid &&
587 scr->cr_uid == tcr->cr_suid &&
588 scr->cr_gid == tcr->cr_gid &&
589 scr->cr_gid == tcr->cr_rgid &&
590 scr->cr_gid == tcr->cr_sgid &&
591 !(tp->p_flag & SNOCD));
592
593 /*
594 * Source credential must have the proc_zone privilege if referencing
595 * a process in another zone.
596 */
597 if (scr->cr_zone != tcr->cr_zone && secpolicy_proc_zone(scr) != 0) {
598 res = EACCES;
599 goto out;
600 }
601
602 if (!(mode & VWRITE)) {
603 if (!idsmatch && secpolicy_proc_owner(scr, tcr, 0) != 0)
604 res = EACCES;
605 goto out;
606 }
607
608 /*
609 * For writing, the effective set of scr must dominate all sets of tcr,
610 * We test Pt <= Es (Et <= Pt so no need to test) and It <= Es
611 * The Limit set of scr must be a superset of the limitset of
612 * tcr.
613 */
614 eset = &CR_OEPRIV(scr);
615
616 if (!priv_issubset(&CR_IPRIV(tcr), eset) ||
617 !priv_issubset(&CR_OPPRIV(tcr), eset) ||
618 !priv_issubset(&CR_LPRIV(tcr), &CR_LPRIV(scr)) ||
619 !idsmatch && secpolicy_proc_owner(scr, tcr, mode) != 0)
620 res = EACCES;
621
622 out:
623 if (res == 0 && pcr != NULL)
624 *pcr = tcr;
625 else
626 crfree(tcr);
627 return (res);
628 }
629
630 /*
631 * Set the privilege aware bit, adding L to E/P if necessary.
632 * Each time we set it, we also clear PRIV_AWARE_RESET.
633 */
634 void
priv_set_PA(cred_t * cr)635 priv_set_PA(cred_t *cr)
636 {
637 ASSERT(cr->cr_ref <= 2);
638
639 if ((CR_FLAGS(cr) & (PRIV_AWARE|PRIV_AWARE_RESET)) == PRIV_AWARE)
640 return;
641
642 CR_FLAGS(cr) |= PRIV_AWARE;
643 CR_FLAGS(cr) &= ~PRIV_AWARE_RESET;
644
645 if (cr->cr_uid == 0)
646 priv_union(&CR_LPRIV(cr), &CR_EPRIV(cr));
647
648 if (cr->cr_uid == 0 || cr->cr_suid == 0 || cr->cr_ruid == 0)
649 priv_union(&CR_LPRIV(cr), &CR_PPRIV(cr));
650 }
651
652 boolean_t
priv_can_clear_PA(const cred_t * cr)653 priv_can_clear_PA(const cred_t *cr)
654 {
655 /*
656 * We can clear PA in the following cases:
657 *
658 * None of the uids are 0.
659 * Any uid == 0 and P == L and (Euid != 0 or E == L)
660 */
661 return ((cr->cr_suid != 0 && cr->cr_ruid != 0 && cr->cr_uid != 0) ||
662 priv_isequalset(&CR_PPRIV(cr), &CR_LPRIV(cr)) &&
663 (cr->cr_uid != 0 || priv_isequalset(&CR_EPRIV(cr), &CR_LPRIV(cr))));
664 }
665
666 /*
667 * Clear privilege aware bit if it is an idempotent operation and by
668 * clearing it the process cannot get to uid 0 and all privileges.
669 *
670 * This function should be called with caution as it may cause "E" to be
671 * lost once a processes assumes euid 0 again.
672 */
673 void
priv_adjust_PA(cred_t * cr)674 priv_adjust_PA(cred_t *cr)
675 {
676 ASSERT(cr->cr_ref <= 2);
677
678 if (!(CR_FLAGS(cr) & PRIV_AWARE) ||
679 !priv_can_clear_PA(cr)) {
680 CR_FLAGS(cr) &= ~PRIV_AWARE_RESET;
681 return;
682 }
683
684 if (CR_FLAGS(cr) & PRIV_AWARE_INHERIT)
685 return;
686
687 /*
688 * We now need to adjust P/E in those cases when uids
689 * are zero; the rules are P' = I & L, E' = I & L;
690 * but since P = L and E = L, we can use P &= I, E &= I,
691 * depending on which uids are 0.
692 */
693 if (cr->cr_suid == 0 || cr->cr_ruid == 0 || cr->cr_uid == 0) {
694 if (cr->cr_uid == 0)
695 priv_intersect(&CR_IPRIV(cr), &CR_EPRIV(cr));
696 priv_intersect(&CR_IPRIV(cr), &CR_PPRIV(cr));
697 }
698
699 CR_FLAGS(cr) &= ~(PRIV_AWARE|PRIV_AWARE_RESET);
700 }
701
702 /*
703 * Reset privilege aware bit if so requested by setting the PRIV_AWARE_RESET
704 * flag.
705 */
706 void
priv_reset_PA(cred_t * cr,boolean_t finalize)707 priv_reset_PA(cred_t *cr, boolean_t finalize)
708 {
709 ASSERT(cr->cr_ref <= 2);
710
711 if ((CR_FLAGS(cr) & (PRIV_AWARE|PRIV_AWARE_RESET)) !=
712 (PRIV_AWARE|PRIV_AWARE_RESET)) {
713 CR_FLAGS(cr) &= ~PRIV_AWARE_RESET;
714 return;
715 }
716
717 /*
718 * When PRIV_AWARE_RESET is enabled, any change of uids causes
719 * a change to the P and E sets. Bracketing with
720 * seteuid(0) ... seteuid(uid)/setreuid(-1, 0) .. setreuid(-1, uid)
721 * will cause the privilege sets "do the right thing.".
722 * When the change of the uid is "final", e.g., by using setuid(uid),
723 * or setreuid(uid, uid) or when the last set*uid() call causes all
724 * uids to be the same, we set P and E to I & L, like when you exec.
725 * We make an exception when all the uids are 0; this is required
726 * when we login as root as in that particular case we cannot
727 * make a distinction between seteuid(0) and seteuid(uid).
728 * We rely on seteuid/setreuid/setuid to tell us with the
729 * "finalize" argument that we no longer expect new uid changes,
730 * cf. setreuid(uid, uid) and setuid(uid).
731 */
732 if (cr->cr_suid == cr->cr_ruid && cr->cr_suid == cr->cr_uid) {
733 if (finalize || cr->cr_uid != 0) {
734 CR_EPRIV(cr) = CR_IPRIV(cr);
735 priv_intersect(&CR_LPRIV(cr), &CR_EPRIV(cr));
736 CR_PPRIV(cr) = CR_EPRIV(cr);
737 CR_FLAGS(cr) &= ~(PRIV_AWARE|PRIV_AWARE_RESET);
738 } else {
739 CR_EPRIV(cr) = CR_PPRIV(cr);
740 }
741 } else if (cr->cr_uid != 0 && (cr->cr_ruid == 0 || cr->cr_suid == 0)) {
742 CR_EPRIV(cr) = CR_IPRIV(cr);
743 priv_intersect(&CR_LPRIV(cr), &CR_EPRIV(cr));
744 }
745 }
746