Line data Source code
1 : /* $OpenBSD: kern_prot.c,v 1.75 2018/06/22 13:33:30 visa Exp $ */
2 : /* $NetBSD: kern_prot.c,v 1.33 1996/02/09 18:59:42 christos Exp $ */
3 :
4 : /*
5 : * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993
6 : * The Regents of the University of California. All rights reserved.
7 : * (c) UNIX System Laboratories, Inc.
8 : * All or some portions of this file are derived from material licensed
9 : * to the University of California by American Telephone and Telegraph
10 : * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11 : * the permission of UNIX System Laboratories, Inc.
12 : *
13 : * Redistribution and use in source and binary forms, with or without
14 : * modification, are permitted provided that the following conditions
15 : * are met:
16 : * 1. Redistributions of source code must retain the above copyright
17 : * notice, this list of conditions and the following disclaimer.
18 : * 2. Redistributions in binary form must reproduce the above copyright
19 : * notice, this list of conditions and the following disclaimer in the
20 : * documentation and/or other materials provided with the distribution.
21 : * 3. Neither the name of the University nor the names of its contributors
22 : * may be used to endorse or promote products derived from this software
23 : * without specific prior written permission.
24 : *
25 : * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 : * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 : * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 : * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 : * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 : * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 : * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 : * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 : * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 : * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 : * SUCH DAMAGE.
36 : *
37 : * @(#)kern_prot.c 8.6 (Berkeley) 1/21/94
38 : */
39 :
40 : /*
41 : * System calls related to processes and protection
42 : */
43 :
44 : #include <sys/param.h>
45 : #include <sys/acct.h>
46 : #include <sys/atomic.h>
47 : #include <sys/systm.h>
48 : #include <sys/ucred.h>
49 : #include <sys/proc.h>
50 : #include <sys/filedesc.h>
51 : #include <sys/pool.h>
52 :
53 : #include <sys/mount.h>
54 : #include <sys/syscallargs.h>
55 : #include <machine/tcb.h>
56 :
57 : inline void
58 0 : crset(struct ucred *newcr, const struct ucred *cr)
59 : {
60 0 : KASSERT(cr->cr_ref > 0);
61 0 : memcpy(
62 : (char *)newcr + offsetof(struct ucred, cr_startcopy),
63 : (const char *)cr + offsetof(struct ucred, cr_startcopy),
64 : sizeof(*cr) - offsetof(struct ucred, cr_startcopy));
65 0 : }
66 :
67 : int
68 0 : sys_getpid(struct proc *p, void *v, register_t *retval)
69 : {
70 :
71 0 : *retval = p->p_p->ps_pid;
72 0 : return (0);
73 : }
74 :
75 : int
76 0 : sys_getthrid(struct proc *p, void *v, register_t *retval)
77 : {
78 :
79 0 : *retval = p->p_tid + THREAD_PID_OFFSET;
80 0 : return (0);
81 : }
82 :
83 : int
84 0 : sys_getppid(struct proc *p, void *v, register_t *retval)
85 : {
86 :
87 0 : *retval = p->p_p->ps_pptr->ps_pid;
88 0 : return (0);
89 : }
90 :
91 : /* Get process group ID; note that POSIX getpgrp takes no parameter */
92 : int
93 0 : sys_getpgrp(struct proc *p, void *v, register_t *retval)
94 : {
95 :
96 0 : *retval = p->p_p->ps_pgrp->pg_id;
97 0 : return (0);
98 : }
99 :
100 : /*
101 : * SysVR.4 compatible getpgid()
102 : */
103 : int
104 0 : sys_getpgid(struct proc *curp, void *v, register_t *retval)
105 : {
106 : struct sys_getpgid_args /* {
107 : syscallarg(pid_t) pid;
108 0 : } */ *uap = v;
109 0 : struct process *targpr = curp->p_p;
110 :
111 0 : if (SCARG(uap, pid) == 0 || SCARG(uap, pid) == targpr->ps_pid)
112 : goto found;
113 0 : if ((targpr = prfind(SCARG(uap, pid))) == NULL)
114 0 : return (ESRCH);
115 0 : if (targpr->ps_session != curp->p_p->ps_session)
116 0 : return (EPERM);
117 : found:
118 0 : *retval = targpr->ps_pgid;
119 0 : return (0);
120 0 : }
121 :
122 : int
123 0 : sys_getsid(struct proc *curp, void *v, register_t *retval)
124 : {
125 : struct sys_getsid_args /* {
126 : syscallarg(pid_t) pid;
127 0 : } */ *uap = v;
128 0 : struct process *targpr = curp->p_p;
129 :
130 0 : if (SCARG(uap, pid) == 0 || SCARG(uap, pid) == targpr->ps_pid)
131 : goto found;
132 0 : if ((targpr = prfind(SCARG(uap, pid))) == NULL)
133 0 : return (ESRCH);
134 0 : if (targpr->ps_session != curp->p_p->ps_session)
135 0 : return (EPERM);
136 : found:
137 : /* Skip exiting processes */
138 0 : if (targpr->ps_pgrp->pg_session->s_leader == NULL)
139 0 : return (ESRCH);
140 0 : *retval = targpr->ps_pgrp->pg_session->s_leader->ps_pid;
141 0 : return (0);
142 0 : }
143 :
144 : int
145 0 : sys_getuid(struct proc *p, void *v, register_t *retval)
146 : {
147 :
148 0 : *retval = p->p_ucred->cr_ruid;
149 0 : return (0);
150 : }
151 :
152 : int
153 0 : sys_geteuid(struct proc *p, void *v, register_t *retval)
154 : {
155 :
156 0 : *retval = p->p_ucred->cr_uid;
157 0 : return (0);
158 : }
159 :
160 : int
161 0 : sys_issetugid(struct proc *p, void *v, register_t *retval)
162 : {
163 0 : if (p->p_p->ps_flags & PS_SUGIDEXEC)
164 0 : *retval = 1;
165 : else
166 0 : *retval = 0;
167 0 : return (0);
168 : }
169 :
170 : int
171 0 : sys_getgid(struct proc *p, void *v, register_t *retval)
172 : {
173 :
174 0 : *retval = p->p_ucred->cr_rgid;
175 0 : return (0);
176 : }
177 :
178 : /*
179 : * Get effective group ID. The "egid" is groups[0], and could be obtained
180 : * via getgroups. This syscall exists because it is somewhat painful to do
181 : * correctly in a library function.
182 : */
183 : int
184 0 : sys_getegid(struct proc *p, void *v, register_t *retval)
185 : {
186 :
187 0 : *retval = p->p_ucred->cr_gid;
188 0 : return (0);
189 : }
190 :
191 : int
192 0 : sys_getgroups(struct proc *p, void *v, register_t *retval)
193 : {
194 : struct sys_getgroups_args /* {
195 : syscallarg(int) gidsetsize;
196 : syscallarg(gid_t *) gidset;
197 0 : } */ *uap = v;
198 0 : struct ucred *uc = p->p_ucred;
199 : u_int ngrp;
200 : int error;
201 :
202 0 : if ((ngrp = SCARG(uap, gidsetsize)) == 0) {
203 0 : *retval = uc->cr_ngroups;
204 0 : return (0);
205 : }
206 0 : if (ngrp < uc->cr_ngroups)
207 0 : return (EINVAL);
208 : ngrp = uc->cr_ngroups;
209 0 : error = copyout(uc->cr_groups, SCARG(uap, gidset),
210 0 : ngrp * sizeof(gid_t));
211 0 : if (error)
212 0 : return (error);
213 0 : *retval = ngrp;
214 0 : return (0);
215 0 : }
216 :
217 : int
218 0 : sys_setsid(struct proc *p, void *v, register_t *retval)
219 : {
220 : struct session *newsess;
221 : struct pgrp *newpgrp;
222 0 : struct process *pr = p->p_p;
223 0 : pid_t pid = pr->ps_pid;
224 :
225 0 : newsess = pool_get(&session_pool, PR_WAITOK);
226 0 : newpgrp = pool_get(&pgrp_pool, PR_WAITOK);
227 :
228 0 : if (pr->ps_pgid == pid || pgfind(pid) != NULL) {
229 0 : pool_put(&pgrp_pool, newpgrp);
230 0 : pool_put(&session_pool, newsess);
231 0 : return (EPERM);
232 : } else {
233 0 : enternewpgrp(pr, newpgrp, newsess);
234 0 : *retval = pid;
235 0 : return (0);
236 : }
237 0 : }
238 :
239 : /*
240 : * set process group (setpgid/old setpgrp)
241 : *
242 : * caller does setpgid(targpid, targpgid)
243 : *
244 : * pid must be caller or child of caller (ESRCH)
245 : * if a child
246 : * pid must be in same session (EPERM)
247 : * pid can't have done an exec (EACCES)
248 : * if pgid != pid
249 : * there must exist some pid in same session having pgid (EPERM)
250 : * pid must not be session leader (EPERM)
251 : */
252 : int
253 0 : sys_setpgid(struct proc *curp, void *v, register_t *retval)
254 : {
255 : struct sys_setpgid_args /* {
256 : syscallarg(pid_t) pid;
257 : syscallarg(pid_t) pgid;
258 0 : } */ *uap = v;
259 0 : struct process *curpr = curp->p_p;
260 : struct process *targpr; /* target process */
261 : struct pgrp *pgrp, *newpgrp; /* target pgrp */
262 : pid_t pid, pgid;
263 : int error;
264 :
265 0 : pid = SCARG(uap, pid);
266 0 : pgid = SCARG(uap, pgid);
267 :
268 0 : if (pgid < 0)
269 0 : return (EINVAL);
270 :
271 0 : newpgrp = pool_get(&pgrp_pool, PR_WAITOK);
272 :
273 0 : if (pid != 0 && pid != curpr->ps_pid) {
274 0 : if ((targpr = prfind(pid)) == 0 || !inferior(targpr, curpr)) {
275 : error = ESRCH;
276 0 : goto out;
277 : }
278 0 : if (targpr->ps_session != curpr->ps_session) {
279 : error = EPERM;
280 0 : goto out;
281 : }
282 0 : if (targpr->ps_flags & PS_EXEC) {
283 : error = EACCES;
284 0 : goto out;
285 : }
286 : } else
287 : targpr = curpr;
288 0 : if (SESS_LEADER(targpr)) {
289 : error = EPERM;
290 0 : goto out;
291 : }
292 0 : if (pgid == 0)
293 0 : pgid = targpr->ps_pid;
294 :
295 : error = 0;
296 0 : if ((pgrp = pgfind(pgid)) == NULL) {
297 : /* can only create a new process group with pgid == pid */
298 0 : if (pgid != targpr->ps_pid)
299 0 : error = EPERM;
300 : else {
301 0 : enternewpgrp(targpr, newpgrp, NULL);
302 : newpgrp = NULL;
303 : }
304 0 : } else if (pgrp != targpr->ps_pgrp) { /* anything to do? */
305 0 : if (pgid != targpr->ps_pid &&
306 0 : pgrp->pg_session != curpr->ps_session)
307 0 : error = EPERM;
308 : else
309 0 : enterthispgrp(targpr, pgrp);
310 : }
311 : out:
312 0 : if (newpgrp != NULL)
313 0 : pool_put(&pgrp_pool, newpgrp);
314 0 : return (error);
315 0 : }
316 :
317 : int
318 0 : sys_getresuid(struct proc *p, void *v, register_t *retval)
319 : {
320 : struct sys_getresuid_args /* {
321 : syscallarg(uid_t *) ruid;
322 : syscallarg(uid_t *) euid;
323 : syscallarg(uid_t *) suid;
324 0 : } */ *uap = v;
325 0 : struct ucred *uc = p->p_ucred;
326 : uid_t *ruid, *euid, *suid;
327 : int error1 = 0, error2 = 0, error3 = 0;
328 :
329 0 : ruid = SCARG(uap, ruid);
330 0 : euid = SCARG(uap, euid);
331 0 : suid = SCARG(uap, suid);
332 :
333 0 : if (ruid != NULL)
334 0 : error1 = copyout(&uc->cr_ruid, ruid, sizeof(*ruid));
335 0 : if (euid != NULL)
336 0 : error2 = copyout(&uc->cr_uid, euid, sizeof(*euid));
337 0 : if (suid != NULL)
338 0 : error3 = copyout(&uc->cr_svuid, suid, sizeof(*suid));
339 :
340 0 : return (error1 ? error1 : error2 ? error2 : error3);
341 : }
342 :
343 : int
344 0 : sys_setresuid(struct proc *p, void *v, register_t *retval)
345 : {
346 : struct sys_setresuid_args /* {
347 : syscallarg(uid_t) ruid;
348 : syscallarg(uid_t) euid;
349 : syscallarg(uid_t) suid;
350 0 : } */ *uap = v;
351 0 : struct process *pr = p->p_p;
352 0 : struct ucred *pruc, *newcred, *uc = p->p_ucred;
353 : uid_t ruid, euid, suid;
354 : int error;
355 :
356 0 : ruid = SCARG(uap, ruid);
357 0 : euid = SCARG(uap, euid);
358 0 : suid = SCARG(uap, suid);
359 :
360 : /*
361 : * make permission checks against the thread's ucred,
362 : * but the actual changes will be to the process's ucred
363 : */
364 0 : pruc = pr->ps_ucred;
365 0 : if ((ruid == (uid_t)-1 || ruid == pruc->cr_ruid) &&
366 0 : (euid == (uid_t)-1 || euid == pruc->cr_uid) &&
367 0 : (suid == (uid_t)-1 || suid == pruc->cr_svuid))
368 0 : return (0); /* no change */
369 :
370 : /*
371 : * Any of the real, effective, and saved uids may be changed
372 : * to the current value of one of the three (root is not limited).
373 : */
374 0 : if (ruid != (uid_t)-1 &&
375 0 : ruid != uc->cr_ruid &&
376 0 : ruid != uc->cr_uid &&
377 0 : ruid != uc->cr_svuid &&
378 0 : (error = suser(p)))
379 0 : return (error);
380 :
381 0 : if (euid != (uid_t)-1 &&
382 0 : euid != uc->cr_ruid &&
383 0 : euid != uc->cr_uid &&
384 0 : euid != uc->cr_svuid &&
385 0 : (error = suser(p)))
386 0 : return (error);
387 :
388 0 : if (suid != (uid_t)-1 &&
389 0 : suid != uc->cr_ruid &&
390 0 : suid != uc->cr_uid &&
391 0 : suid != uc->cr_svuid &&
392 0 : (error = suser(p)))
393 0 : return (error);
394 :
395 : /*
396 : * Copy credentials so other references do not see our changes.
397 : * ps_ucred may change during the crget().
398 : */
399 0 : newcred = crget();
400 0 : pruc = pr->ps_ucred;
401 0 : crset(newcred, pruc);
402 :
403 : /*
404 : * Note that unlike the other set*uid() calls, each
405 : * uid type is set independently of the others.
406 : */
407 0 : if (ruid != (uid_t)-1)
408 0 : newcred->cr_ruid = ruid;
409 0 : if (euid != (uid_t)-1)
410 0 : newcred->cr_uid = euid;
411 0 : if (suid != (uid_t)-1)
412 0 : newcred->cr_svuid = suid;
413 0 : pr->ps_ucred = newcred;
414 0 : atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID);
415 :
416 : /* now that we can sleep, transfer proc count to new user */
417 0 : if (ruid != (uid_t)-1 && ruid != pruc->cr_ruid) {
418 0 : chgproccnt(pruc->cr_ruid, -1);
419 0 : chgproccnt(ruid, 1);
420 0 : }
421 0 : crfree(pruc);
422 :
423 0 : return (0);
424 0 : }
425 :
426 : int
427 0 : sys_getresgid(struct proc *p, void *v, register_t *retval)
428 : {
429 : struct sys_getresgid_args /* {
430 : syscallarg(gid_t *) rgid;
431 : syscallarg(gid_t *) egid;
432 : syscallarg(gid_t *) sgid;
433 0 : } */ *uap = v;
434 0 : struct ucred *uc = p->p_ucred;
435 : gid_t *rgid, *egid, *sgid;
436 : int error1 = 0, error2 = 0, error3 = 0;
437 :
438 0 : rgid = SCARG(uap, rgid);
439 0 : egid = SCARG(uap, egid);
440 0 : sgid = SCARG(uap, sgid);
441 :
442 0 : if (rgid != NULL)
443 0 : error1 = copyout(&uc->cr_rgid, rgid, sizeof(*rgid));
444 0 : if (egid != NULL)
445 0 : error2 = copyout(&uc->cr_gid, egid, sizeof(*egid));
446 0 : if (sgid != NULL)
447 0 : error3 = copyout(&uc->cr_svgid, sgid, sizeof(*sgid));
448 :
449 0 : return (error1 ? error1 : error2 ? error2 : error3);
450 : }
451 :
452 : int
453 0 : sys_setresgid(struct proc *p, void *v, register_t *retval)
454 : {
455 : struct sys_setresgid_args /* {
456 : syscallarg(gid_t) rgid;
457 : syscallarg(gid_t) egid;
458 : syscallarg(gid_t) sgid;
459 0 : } */ *uap = v;
460 0 : struct process *pr = p->p_p;
461 0 : struct ucred *pruc, *newcred, *uc = p->p_ucred;
462 : gid_t rgid, egid, sgid;
463 : int error;
464 :
465 0 : rgid = SCARG(uap, rgid);
466 0 : egid = SCARG(uap, egid);
467 0 : sgid = SCARG(uap, sgid);
468 :
469 : /*
470 : * make permission checks against the thread's ucred,
471 : * but the actual changes will be to the process's ucred
472 : */
473 0 : pruc = pr->ps_ucred;
474 0 : if ((rgid == (gid_t)-1 || rgid == pruc->cr_rgid) &&
475 0 : (egid == (gid_t)-1 || egid == pruc->cr_gid) &&
476 0 : (sgid == (gid_t)-1 || sgid == pruc->cr_svgid))
477 0 : return (0); /* no change */
478 :
479 : /*
480 : * Any of the real, effective, and saved gids may be changed
481 : * to the current value of one of the three (root is not limited).
482 : */
483 0 : if (rgid != (gid_t)-1 &&
484 0 : rgid != uc->cr_rgid &&
485 0 : rgid != uc->cr_gid &&
486 0 : rgid != uc->cr_svgid &&
487 0 : (error = suser(p)))
488 0 : return (error);
489 :
490 0 : if (egid != (gid_t)-1 &&
491 0 : egid != uc->cr_rgid &&
492 0 : egid != uc->cr_gid &&
493 0 : egid != uc->cr_svgid &&
494 0 : (error = suser(p)))
495 0 : return (error);
496 :
497 0 : if (sgid != (gid_t)-1 &&
498 0 : sgid != uc->cr_rgid &&
499 0 : sgid != uc->cr_gid &&
500 0 : sgid != uc->cr_svgid &&
501 0 : (error = suser(p)))
502 0 : return (error);
503 :
504 : /*
505 : * Copy credentials so other references do not see our changes.
506 : * ps_ucred may change during the crget().
507 : */
508 0 : newcred = crget();
509 0 : pruc = pr->ps_ucred;
510 0 : crset(newcred, pruc);
511 :
512 : /*
513 : * Note that unlike the other set*gid() calls, each
514 : * gid type is set independently of the others.
515 : */
516 0 : if (rgid != (gid_t)-1)
517 0 : newcred->cr_rgid = rgid;
518 0 : if (egid != (gid_t)-1)
519 0 : newcred->cr_gid = egid;
520 0 : if (sgid != (gid_t)-1)
521 0 : newcred->cr_svgid = sgid;
522 0 : pr->ps_ucred = newcred;
523 0 : atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID);
524 0 : crfree(pruc);
525 0 : return (0);
526 0 : }
527 :
528 : int
529 0 : sys_setregid(struct proc *p, void *v, register_t *retval)
530 : {
531 : struct sys_setregid_args /* {
532 : syscallarg(gid_t) rgid;
533 : syscallarg(gid_t) egid;
534 0 : } */ *uap = v;
535 0 : struct process *pr = p->p_p;
536 0 : struct ucred *pruc, *newcred, *uc = p->p_ucred;
537 : gid_t rgid, egid;
538 : int error;
539 :
540 0 : rgid = SCARG(uap, rgid);
541 0 : egid = SCARG(uap, egid);
542 :
543 : /*
544 : * make permission checks against the thread's ucred,
545 : * but the actual changes will be to the process's ucred
546 : *
547 : * The saved gid check here is complicated: we reset the
548 : * saved gid to the real gid if the real gid is specified
549 : * *and* either it's changing _or_ the saved gid won't equal
550 : * the effective gid. So, the svgid *won't* change when
551 : * the rgid isn't specified or when the rgid isn't changing
552 : * and the svgid equals the requested egid.
553 : */
554 0 : pruc = pr->ps_ucred;
555 0 : if ((rgid == (gid_t)-1 || rgid == pruc->cr_rgid) &&
556 0 : (egid == (gid_t)-1 || egid == pruc->cr_gid) &&
557 0 : (rgid == (gid_t)-1 || (rgid == pruc->cr_rgid &&
558 0 : pruc->cr_svgid == (egid != (gid_t)-1 ? egid : pruc->cr_gid))))
559 0 : return (0); /* no change */
560 :
561 : /*
562 : * Any of the real, effective, and saved gids may be changed
563 : * to the current value of one of the three (root is not limited).
564 : */
565 0 : if (rgid != (gid_t)-1 &&
566 0 : rgid != uc->cr_rgid &&
567 0 : rgid != uc->cr_gid &&
568 0 : rgid != uc->cr_svgid &&
569 0 : (error = suser(p)))
570 0 : return (error);
571 :
572 0 : if (egid != (gid_t)-1 &&
573 0 : egid != uc->cr_rgid &&
574 0 : egid != uc->cr_gid &&
575 0 : egid != uc->cr_svgid &&
576 0 : (error = suser(p)))
577 0 : return (error);
578 :
579 : /*
580 : * Copy credentials so other references do not see our changes.
581 : * ps_ucred may change during the crget().
582 : */
583 0 : newcred = crget();
584 0 : pruc = pr->ps_ucred;
585 0 : crset(newcred, pruc);
586 :
587 0 : if (rgid != (gid_t)-1)
588 0 : newcred->cr_rgid = rgid;
589 0 : if (egid != (gid_t)-1)
590 0 : newcred->cr_gid = egid;
591 :
592 : /*
593 : * The saved gid presents a bit of a dilemma, as it did not
594 : * exist when setregid(2) was conceived. We only set the saved
595 : * gid when the real gid is specified and either its value would
596 : * change, or where the saved and effective gids are different.
597 : */
598 0 : if (rgid != (gid_t)-1 && (rgid != pruc->cr_rgid ||
599 0 : pruc->cr_svgid != (egid != (gid_t)-1 ? egid : pruc->cr_gid)))
600 0 : newcred->cr_svgid = rgid;
601 0 : pr->ps_ucred = newcred;
602 0 : atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID);
603 0 : crfree(pruc);
604 0 : return (0);
605 0 : }
606 :
607 : int
608 0 : sys_setreuid(struct proc *p, void *v, register_t *retval)
609 : {
610 : struct sys_setreuid_args /* {
611 : syscallarg(uid_t) ruid;
612 : syscallarg(uid_t) euid;
613 0 : } */ *uap = v;
614 0 : struct process *pr = p->p_p;
615 0 : struct ucred *pruc, *newcred, *uc = p->p_ucred;
616 : uid_t ruid, euid;
617 : int error;
618 :
619 0 : ruid = SCARG(uap, ruid);
620 0 : euid = SCARG(uap, euid);
621 :
622 : /*
623 : * make permission checks against the thread's ucred,
624 : * but the actual changes will be to the process's ucred
625 : *
626 : * The saved uid check here is complicated: we reset the
627 : * saved uid to the real uid if the real uid is specified
628 : * *and* either it's changing _or_ the saved uid won't equal
629 : * the effective uid. So, the svuid *won't* change when
630 : * the ruid isn't specified or when the ruid isn't changing
631 : * and the svuid equals the requested euid.
632 : */
633 0 : pruc = pr->ps_ucred;
634 0 : if ((ruid == (uid_t)-1 || ruid == pruc->cr_ruid) &&
635 0 : (euid == (uid_t)-1 || euid == pruc->cr_uid) &&
636 0 : (ruid == (uid_t)-1 || (ruid == pruc->cr_ruid &&
637 0 : pruc->cr_svuid == (euid != (uid_t)-1 ? euid : pruc->cr_uid))))
638 0 : return (0); /* no change */
639 :
640 : /*
641 : * Any of the real, effective, and saved uids may be changed
642 : * to the current value of one of the three (root is not limited).
643 : */
644 0 : if (ruid != (uid_t)-1 &&
645 0 : ruid != uc->cr_ruid &&
646 0 : ruid != uc->cr_uid &&
647 0 : ruid != uc->cr_svuid &&
648 0 : (error = suser(p)))
649 0 : return (error);
650 :
651 0 : if (euid != (uid_t)-1 &&
652 0 : euid != uc->cr_ruid &&
653 0 : euid != uc->cr_uid &&
654 0 : euid != uc->cr_svuid &&
655 0 : (error = suser(p)))
656 0 : return (error);
657 :
658 : /*
659 : * Copy credentials so other references do not see our changes.
660 : * ps_ucred may change during the crget().
661 : */
662 0 : newcred = crget();
663 0 : pruc = pr->ps_ucred;
664 0 : crset(newcred, pruc);
665 :
666 0 : if (ruid != (uid_t)-1)
667 0 : newcred->cr_ruid = ruid;
668 0 : if (euid != (uid_t)-1)
669 0 : newcred->cr_uid = euid;
670 :
671 : /*
672 : * The saved uid presents a bit of a dilemma, as it did not
673 : * exist when setreuid(2) was conceived. We only set the saved
674 : * uid when the real uid is specified and either its value would
675 : * change, or where the saved and effective uids are different.
676 : */
677 0 : if (ruid != (uid_t)-1 && (ruid != pruc->cr_ruid ||
678 0 : pruc->cr_svuid != (euid != (uid_t)-1 ? euid : pruc->cr_uid)))
679 0 : newcred->cr_svuid = ruid;
680 0 : pr->ps_ucred = newcred;
681 0 : atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID);
682 :
683 : /* now that we can sleep, transfer proc count to new user */
684 0 : if (ruid != (uid_t)-1 && ruid != pruc->cr_ruid) {
685 0 : chgproccnt(pruc->cr_ruid, -1);
686 0 : chgproccnt(ruid, 1);
687 0 : }
688 0 : crfree(pruc);
689 :
690 0 : return (0);
691 0 : }
692 :
693 : int
694 0 : sys_setuid(struct proc *p, void *v, register_t *retval)
695 : {
696 : struct sys_setuid_args /* {
697 : syscallarg(uid_t) uid;
698 0 : } */ *uap = v;
699 0 : struct process *pr = p->p_p;
700 0 : struct ucred *pruc, *newcred, *uc = p->p_ucred;
701 : uid_t uid;
702 : int did_real, error;
703 :
704 0 : uid = SCARG(uap, uid);
705 :
706 0 : pruc = pr->ps_ucred;
707 0 : if (pruc->cr_uid == uid &&
708 0 : pruc->cr_ruid == uid &&
709 0 : pruc->cr_svuid == uid)
710 0 : return (0);
711 :
712 0 : if (uid != uc->cr_ruid &&
713 0 : uid != uc->cr_svuid &&
714 0 : uid != uc->cr_uid &&
715 0 : (error = suser(p)))
716 0 : return (error);
717 :
718 : /*
719 : * Copy credentials so other references do not see our changes.
720 : * ps_ucred may change during the crget().
721 : */
722 0 : newcred = crget();
723 0 : pruc = pr->ps_ucred;
724 0 : crset(newcred, pruc);
725 :
726 : /*
727 : * Everything's okay, do it.
728 : */
729 0 : if (uid == pruc->cr_uid || suser(p) == 0) {
730 : did_real = 1;
731 0 : newcred->cr_ruid = uid;
732 0 : newcred->cr_svuid = uid;
733 0 : } else
734 : did_real = 0;
735 0 : newcred->cr_uid = uid;
736 0 : pr->ps_ucred = newcred;
737 0 : atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID);
738 :
739 : /*
740 : * Transfer proc count to new user.
741 : */
742 0 : if (did_real && uid != pruc->cr_ruid) {
743 0 : chgproccnt(pruc->cr_ruid, -1);
744 0 : chgproccnt(uid, 1);
745 0 : }
746 0 : crfree(pruc);
747 :
748 0 : return (0);
749 0 : }
750 :
751 : int
752 0 : sys_seteuid(struct proc *p, void *v, register_t *retval)
753 : {
754 : struct sys_seteuid_args /* {
755 : syscallarg(uid_t) euid;
756 0 : } */ *uap = v;
757 0 : struct process *pr = p->p_p;
758 0 : struct ucred *pruc, *newcred, *uc = p->p_ucred;
759 : uid_t euid;
760 : int error;
761 :
762 0 : euid = SCARG(uap, euid);
763 :
764 0 : if (pr->ps_ucred->cr_uid == euid)
765 0 : return (0);
766 :
767 0 : if (euid != uc->cr_ruid && euid != uc->cr_svuid &&
768 0 : (error = suser(p)))
769 0 : return (error);
770 :
771 : /*
772 : * Copy credentials so other references do not see our changes.
773 : * ps_ucred may change during the crget().
774 : */
775 0 : newcred = crget();
776 0 : pruc = pr->ps_ucred;
777 0 : crset(newcred, pruc);
778 0 : newcred->cr_uid = euid;
779 0 : pr->ps_ucred = newcred;
780 0 : atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID);
781 0 : crfree(pruc);
782 0 : return (0);
783 0 : }
784 :
785 : int
786 0 : sys_setgid(struct proc *p, void *v, register_t *retval)
787 : {
788 : struct sys_setgid_args /* {
789 : syscallarg(gid_t) gid;
790 0 : } */ *uap = v;
791 0 : struct process *pr = p->p_p;
792 0 : struct ucred *pruc, *newcred, *uc = p->p_ucred;
793 : gid_t gid;
794 : int error;
795 :
796 0 : gid = SCARG(uap, gid);
797 :
798 0 : pruc = pr->ps_ucred;
799 0 : if (pruc->cr_gid == gid &&
800 0 : pruc->cr_rgid == gid &&
801 0 : pruc->cr_svgid == gid)
802 0 : return (0);
803 :
804 0 : if (gid != uc->cr_rgid &&
805 0 : gid != uc->cr_svgid &&
806 0 : gid != uc->cr_gid &&
807 0 : (error = suser(p)))
808 0 : return (error);
809 :
810 : /*
811 : * Copy credentials so other references do not see our changes.
812 : * ps_ucred may change during the crget().
813 : */
814 0 : newcred = crget();
815 0 : pruc = pr->ps_ucred;
816 0 : crset(newcred, pruc);
817 :
818 0 : if (gid == pruc->cr_gid || suser(p) == 0) {
819 0 : newcred->cr_rgid = gid;
820 0 : newcred->cr_svgid = gid;
821 0 : }
822 0 : newcred->cr_gid = gid;
823 0 : pr->ps_ucred = newcred;
824 0 : atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID);
825 0 : crfree(pruc);
826 0 : return (0);
827 0 : }
828 :
829 : int
830 0 : sys_setegid(struct proc *p, void *v, register_t *retval)
831 : {
832 : struct sys_setegid_args /* {
833 : syscallarg(gid_t) egid;
834 0 : } */ *uap = v;
835 0 : struct process *pr = p->p_p;
836 0 : struct ucred *pruc, *newcred, *uc = p->p_ucred;
837 : gid_t egid;
838 : int error;
839 :
840 0 : egid = SCARG(uap, egid);
841 :
842 0 : if (pr->ps_ucred->cr_gid == egid)
843 0 : return (0);
844 :
845 0 : if (egid != uc->cr_rgid && egid != uc->cr_svgid &&
846 0 : (error = suser(p)))
847 0 : return (error);
848 :
849 : /*
850 : * Copy credentials so other references do not see our changes.
851 : * ps_ucred may change during the crget().
852 : */
853 0 : newcred = crget();
854 0 : pruc = pr->ps_ucred;
855 0 : crset(newcred, pruc);
856 0 : newcred->cr_gid = egid;
857 0 : pr->ps_ucred = newcred;
858 0 : atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID);
859 0 : crfree(pruc);
860 0 : return (0);
861 0 : }
862 :
863 : int
864 0 : sys_setgroups(struct proc *p, void *v, register_t *retval)
865 : {
866 : struct sys_setgroups_args /* {
867 : syscallarg(int) gidsetsize;
868 : syscallarg(const gid_t *) gidset;
869 0 : } */ *uap = v;
870 0 : struct process *pr = p->p_p;
871 : struct ucred *pruc, *newcred;
872 0 : gid_t groups[NGROUPS_MAX];
873 : u_int ngrp;
874 : int error;
875 :
876 0 : if ((error = suser(p)) != 0)
877 0 : return (error);
878 0 : ngrp = SCARG(uap, gidsetsize);
879 0 : if (ngrp > NGROUPS_MAX)
880 0 : return (EINVAL);
881 0 : error = copyin(SCARG(uap, gidset), groups, ngrp * sizeof(gid_t));
882 0 : if (error == 0) {
883 0 : newcred = crget();
884 0 : pruc = pr->ps_ucred;
885 0 : crset(newcred, pruc);
886 0 : memcpy(newcred->cr_groups, groups, ngrp * sizeof(gid_t));
887 0 : newcred->cr_ngroups = ngrp;
888 0 : pr->ps_ucred = newcred;
889 0 : atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID);
890 0 : crfree(pruc);
891 0 : }
892 0 : return (error);
893 0 : }
894 :
895 : /*
896 : * Check if gid is a member of the group set.
897 : */
898 : int
899 0 : groupmember(gid_t gid, struct ucred *cred)
900 : {
901 : gid_t *gp;
902 : gid_t *egp;
903 :
904 0 : if (cred->cr_gid == gid)
905 0 : return (1);
906 0 : egp = &(cred->cr_groups[cred->cr_ngroups]);
907 0 : for (gp = cred->cr_groups; gp < egp; gp++)
908 0 : if (*gp == gid)
909 0 : return (1);
910 0 : return (0);
911 0 : }
912 :
913 : /*
914 : * Test whether this process has special user powers.
915 : * Returns 0 or error.
916 : */
917 : int
918 0 : suser(struct proc *p)
919 : {
920 0 : struct ucred *cred = p->p_ucred;
921 :
922 0 : if (cred->cr_uid == 0)
923 0 : return (0);
924 0 : return (EPERM);
925 0 : }
926 :
927 : /*
928 : * replacement for old suser, for callers who don't have a process
929 : */
930 : int
931 0 : suser_ucred(struct ucred *cred)
932 : {
933 0 : if (cred->cr_uid == 0)
934 0 : return (0);
935 0 : return (EPERM);
936 0 : }
937 :
938 : /*
939 : * Allocate a zeroed cred structure.
940 : */
941 : struct ucred *
942 0 : crget(void)
943 : {
944 : struct ucred *cr;
945 :
946 0 : cr = pool_get(&ucred_pool, PR_WAITOK|PR_ZERO);
947 0 : cr->cr_ref = 1;
948 0 : return (cr);
949 : }
950 :
951 : /*
952 : * Increment the reference count of a cred structure.
953 : * Returns the passed structure.
954 : */
955 : struct ucred *
956 0 : crhold(struct ucred *cr)
957 : {
958 0 : atomic_inc_int(&cr->cr_ref);
959 0 : return (cr);
960 : }
961 :
962 : /*
963 : * Free a cred structure.
964 : * Throws away space when ref count gets to 0.
965 : */
966 : void
967 0 : crfree(struct ucred *cr)
968 : {
969 :
970 0 : if (atomic_dec_int_nv(&cr->cr_ref) == 0)
971 0 : pool_put(&ucred_pool, cr);
972 0 : }
973 :
974 : /*
975 : * Copy cred structure to a new one and free the old one.
976 : */
977 : struct ucred *
978 0 : crcopy(struct ucred *cr)
979 : {
980 : struct ucred *newcr;
981 :
982 0 : if (cr->cr_ref == 1)
983 0 : return (cr);
984 0 : newcr = crget();
985 0 : *newcr = *cr;
986 0 : crfree(cr);
987 0 : newcr->cr_ref = 1;
988 0 : return (newcr);
989 0 : }
990 :
991 : /*
992 : * Dup cred struct to a new held one.
993 : */
994 : struct ucred *
995 0 : crdup(struct ucred *cr)
996 : {
997 : struct ucred *newcr;
998 :
999 0 : newcr = crget();
1000 0 : *newcr = *cr;
1001 0 : newcr->cr_ref = 1;
1002 0 : return (newcr);
1003 : }
1004 :
1005 : /*
1006 : * Convert the userspace xucred to a kernel ucred
1007 : */
1008 : int
1009 0 : crfromxucred(struct ucred *cr, const struct xucred *xcr)
1010 : {
1011 0 : if (xcr->cr_ngroups < 0 || xcr->cr_ngroups > NGROUPS_MAX)
1012 0 : return (EINVAL);
1013 0 : cr->cr_ref = 1;
1014 0 : cr->cr_uid = xcr->cr_uid;
1015 0 : cr->cr_gid = xcr->cr_gid;
1016 0 : cr->cr_ngroups = xcr->cr_ngroups;
1017 0 : memcpy(cr->cr_groups, xcr->cr_groups,
1018 : sizeof(cr->cr_groups[0]) * xcr->cr_ngroups);
1019 0 : return (0);
1020 0 : }
1021 :
1022 : /*
1023 : * Get login name, if available.
1024 : */
1025 : int
1026 0 : sys_getlogin_r(struct proc *p, void *v, register_t *retval)
1027 : {
1028 : struct sys_getlogin_r_args /* {
1029 : syscallarg(char *) namebuf;
1030 : syscallarg(size_t) namelen;
1031 0 : } */ *uap = v;
1032 0 : size_t namelen = SCARG(uap, namelen);
1033 0 : struct session *s = p->p_p->ps_pgrp->pg_session;
1034 : int error;
1035 :
1036 0 : if (namelen > sizeof(s->s_login))
1037 0 : namelen = sizeof(s->s_login);
1038 0 : error = copyoutstr(s->s_login, SCARG(uap, namebuf), namelen, NULL);
1039 0 : if (error == ENAMETOOLONG)
1040 : error = ERANGE;
1041 0 : *retval = error;
1042 0 : return (0);
1043 : }
1044 :
1045 : /*
1046 : * Set login name.
1047 : */
1048 : int
1049 0 : sys_setlogin(struct proc *p, void *v, register_t *retval)
1050 : {
1051 : struct sys_setlogin_args /* {
1052 : syscallarg(const char *) namebuf;
1053 0 : } */ *uap = v;
1054 0 : struct session *s = p->p_p->ps_pgrp->pg_session;
1055 0 : char buf[sizeof(s->s_login)];
1056 : int error;
1057 :
1058 0 : if ((error = suser(p)) != 0)
1059 0 : return (error);
1060 0 : error = copyinstr(SCARG(uap, namebuf), buf, sizeof(buf), NULL);
1061 0 : if (error == 0)
1062 0 : strlcpy(s->s_login, buf, sizeof(s->s_login));
1063 0 : else if (error == ENAMETOOLONG)
1064 0 : error = EINVAL;
1065 0 : return (error);
1066 0 : }
1067 :
1068 : /*
1069 : * Check if a process is allowed to raise its privileges.
1070 : */
1071 : int
1072 0 : proc_cansugid(struct proc *p)
1073 : {
1074 : /* ptrace(2)d processes shouldn't. */
1075 0 : if ((p->p_p->ps_flags & PS_TRACED) != 0)
1076 0 : return (0);
1077 :
1078 : /* processes with shared filedescriptors shouldn't. */
1079 0 : if (p->p_fd->fd_refcnt > 1)
1080 0 : return (0);
1081 :
1082 : /* Allow. */
1083 0 : return (1);
1084 0 : }
1085 :
1086 : /*
1087 : * Set address of the proc's thread-control-block
1088 : */
1089 : int
1090 0 : sys___set_tcb(struct proc *p, void *v, register_t *retval)
1091 : {
1092 : struct sys___set_tcb_args /* {
1093 : syscallarg(void *) tcb;
1094 0 : } */ *uap = v;
1095 0 : void *tcb = SCARG(uap, tcb);
1096 :
1097 : #ifdef TCB_INVALID
1098 0 : if (TCB_INVALID(tcb))
1099 0 : return EINVAL;
1100 : #endif /* TCB_INVALID */
1101 0 : TCB_SET(p, tcb);
1102 0 : return (0);
1103 0 : }
1104 :
1105 : /*
1106 : * Get address of the proc's thread-control-block
1107 : */
1108 : int
1109 0 : sys___get_tcb(struct proc *p, void *v, register_t *retval)
1110 : {
1111 0 : *retval = (register_t)TCB_GET(p);
1112 0 : return (0);
1113 : }
1114 :
1115 : /*
1116 : * Refresh the thread's reference to the process's credentials
1117 : */
1118 : void
1119 0 : dorefreshcreds(struct process *pr, struct proc *p)
1120 : {
1121 0 : struct ucred *uc = p->p_ucred;
1122 :
1123 0 : KERNEL_LOCK(); /* XXX should be PROCESS_RLOCK(pr) */
1124 0 : if (uc != pr->ps_ucred) {
1125 0 : p->p_ucred = pr->ps_ucred;
1126 0 : crhold(p->p_ucred);
1127 0 : crfree(uc);
1128 0 : }
1129 0 : KERNEL_UNLOCK();
1130 0 : }
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