1 /*-
2 * Copyright (c) 2014 John Baldwin
3 * Copyright (c) 2014 The FreeBSD Foundation
4 *
5 * Portions of this software were developed by Konstantin Belousov
6 * under sponsorship from the FreeBSD Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD: stable/10/sys/kern/kern_procctl.c 326397 2017-11-30 14:38:07Z kib $");
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/capability.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/priv.h>
39 #include <sys/proc.h>
40 #include <sys/procctl.h>
41 #include <sys/sx.h>
42 #include <sys/syscallsubr.h>
43 #include <sys/sysproto.h>
44 #include <sys/wait.h>
45
46 static int
protect_setchild(struct thread * td,struct proc * p,int flags)47 protect_setchild(struct thread *td, struct proc *p, int flags)
48 {
49
50 PROC_LOCK_ASSERT(p, MA_OWNED);
51 if (p->p_flag & P_SYSTEM || p_cansched(td, p) != 0)
52 return (0);
53 if (flags & PPROT_SET) {
54 p->p_flag |= P_PROTECTED;
55 if (flags & PPROT_INHERIT)
56 p->p_flag2 |= P2_INHERIT_PROTECTED;
57 } else {
58 p->p_flag &= ~P_PROTECTED;
59 p->p_flag2 &= ~P2_INHERIT_PROTECTED;
60 }
61 return (1);
62 }
63
64 static int
protect_setchildren(struct thread * td,struct proc * top,int flags)65 protect_setchildren(struct thread *td, struct proc *top, int flags)
66 {
67 struct proc *p;
68 int ret;
69
70 p = top;
71 ret = 0;
72 sx_assert(&proctree_lock, SX_LOCKED);
73 for (;;) {
74 ret |= protect_setchild(td, p, flags);
75 PROC_UNLOCK(p);
76 /*
77 * If this process has children, descend to them next,
78 * otherwise do any siblings, and if done with this level,
79 * follow back up the tree (but not past top).
80 */
81 if (!LIST_EMPTY(&p->p_children))
82 p = LIST_FIRST(&p->p_children);
83 else for (;;) {
84 if (p == top) {
85 PROC_LOCK(p);
86 return (ret);
87 }
88 if (LIST_NEXT(p, p_sibling)) {
89 p = LIST_NEXT(p, p_sibling);
90 break;
91 }
92 p = p->p_pptr;
93 }
94 PROC_LOCK(p);
95 }
96 }
97
98 static int
protect_set(struct thread * td,struct proc * p,int flags)99 protect_set(struct thread *td, struct proc *p, int flags)
100 {
101 int error, ret;
102
103 switch (PPROT_OP(flags)) {
104 case PPROT_SET:
105 case PPROT_CLEAR:
106 break;
107 default:
108 return (EINVAL);
109 }
110
111 if ((PPROT_FLAGS(flags) & ~(PPROT_DESCEND | PPROT_INHERIT)) != 0)
112 return (EINVAL);
113
114 error = priv_check(td, PRIV_VM_MADV_PROTECT);
115 if (error)
116 return (error);
117
118 if (flags & PPROT_DESCEND)
119 ret = protect_setchildren(td, p, flags);
120 else
121 ret = protect_setchild(td, p, flags);
122 if (ret == 0)
123 return (EPERM);
124 return (0);
125 }
126
127 static int
reap_acquire(struct thread * td,struct proc * p)128 reap_acquire(struct thread *td, struct proc *p)
129 {
130
131 sx_assert(&proctree_lock, SX_XLOCKED);
132 if (p != curproc)
133 return (EPERM);
134 if ((p->p_treeflag & P_TREE_REAPER) != 0)
135 return (EBUSY);
136 p->p_treeflag |= P_TREE_REAPER;
137 /*
138 * We do not reattach existing children and the whole tree
139 * under them to us, since p->p_reaper already seen them.
140 */
141 return (0);
142 }
143
144 static int
reap_release(struct thread * td,struct proc * p)145 reap_release(struct thread *td, struct proc *p)
146 {
147
148 sx_assert(&proctree_lock, SX_XLOCKED);
149 if (p != curproc)
150 return (EPERM);
151 if (p == initproc)
152 return (EINVAL);
153 if ((p->p_treeflag & P_TREE_REAPER) == 0)
154 return (EINVAL);
155 reaper_abandon_children(p, false);
156 return (0);
157 }
158
159 static int
reap_status(struct thread * td,struct proc * p,struct procctl_reaper_status * rs)160 reap_status(struct thread *td, struct proc *p,
161 struct procctl_reaper_status *rs)
162 {
163 struct proc *reap, *p2, *first_p;
164
165 sx_assert(&proctree_lock, SX_LOCKED);
166 bzero(rs, sizeof(*rs));
167 if ((p->p_treeflag & P_TREE_REAPER) == 0) {
168 reap = p->p_reaper;
169 } else {
170 reap = p;
171 rs->rs_flags |= REAPER_STATUS_OWNED;
172 }
173 if (reap == initproc)
174 rs->rs_flags |= REAPER_STATUS_REALINIT;
175 rs->rs_reaper = reap->p_pid;
176 rs->rs_descendants = 0;
177 rs->rs_children = 0;
178 if (!LIST_EMPTY(&reap->p_reaplist)) {
179 first_p = LIST_FIRST(&reap->p_children);
180 if (first_p == NULL)
181 first_p = LIST_FIRST(&reap->p_reaplist);
182 rs->rs_pid = first_p->p_pid;
183 LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
184 if (proc_realparent(p2) == reap)
185 rs->rs_children++;
186 rs->rs_descendants++;
187 }
188 } else {
189 rs->rs_pid = -1;
190 }
191 return (0);
192 }
193
194 static int
reap_getpids(struct thread * td,struct proc * p,struct procctl_reaper_pids * rp)195 reap_getpids(struct thread *td, struct proc *p, struct procctl_reaper_pids *rp)
196 {
197 struct proc *reap, *p2;
198 struct procctl_reaper_pidinfo *pi, *pip;
199 u_int i, n;
200 int error;
201
202 sx_assert(&proctree_lock, SX_LOCKED);
203 PROC_UNLOCK(p);
204 reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
205 n = i = 0;
206 error = 0;
207 LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling)
208 n++;
209 sx_unlock(&proctree_lock);
210 if (rp->rp_count < n)
211 n = rp->rp_count;
212 pi = malloc(n * sizeof(*pi), M_TEMP, M_WAITOK);
213 sx_slock(&proctree_lock);
214 LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
215 if (i == n)
216 break;
217 pip = &pi[i];
218 bzero(pip, sizeof(*pip));
219 pip->pi_pid = p2->p_pid;
220 pip->pi_subtree = p2->p_reapsubtree;
221 pip->pi_flags = REAPER_PIDINFO_VALID;
222 if (proc_realparent(p2) == reap)
223 pip->pi_flags |= REAPER_PIDINFO_CHILD;
224 if ((p2->p_treeflag & P_TREE_REAPER) != 0)
225 pip->pi_flags |= REAPER_PIDINFO_REAPER;
226 i++;
227 }
228 sx_sunlock(&proctree_lock);
229 error = copyout(pi, rp->rp_pids, i * sizeof(*pi));
230 free(pi, M_TEMP);
231 sx_slock(&proctree_lock);
232 PROC_LOCK(p);
233 return (error);
234 }
235
236 static void
reap_kill_proc(struct thread * td,struct proc * p2,ksiginfo_t * ksi,struct procctl_reaper_kill * rk,int * error)237 reap_kill_proc(struct thread *td, struct proc *p2, ksiginfo_t *ksi,
238 struct procctl_reaper_kill *rk, int *error)
239 {
240 int error1;
241
242 PROC_LOCK(p2);
243 error1 = p_cansignal(td, p2, rk->rk_sig);
244 if (error1 == 0) {
245 pksignal(p2, rk->rk_sig, ksi);
246 rk->rk_killed++;
247 *error = error1;
248 } else if (*error == ESRCH) {
249 rk->rk_fpid = p2->p_pid;
250 *error = error1;
251 }
252 PROC_UNLOCK(p2);
253 }
254
255 struct reap_kill_tracker {
256 struct proc *parent;
257 TAILQ_ENTRY(reap_kill_tracker) link;
258 };
259
260 TAILQ_HEAD(reap_kill_tracker_head, reap_kill_tracker);
261
262 static void
reap_kill_sched(struct reap_kill_tracker_head * tracker,struct proc * p2)263 reap_kill_sched(struct reap_kill_tracker_head *tracker, struct proc *p2)
264 {
265 struct reap_kill_tracker *t;
266
267 t = malloc(sizeof(struct reap_kill_tracker), M_TEMP, M_WAITOK);
268 t->parent = p2;
269 TAILQ_INSERT_TAIL(tracker, t, link);
270 }
271
272 static int
reap_kill(struct thread * td,struct proc * p,struct procctl_reaper_kill * rk)273 reap_kill(struct thread *td, struct proc *p, struct procctl_reaper_kill *rk)
274 {
275 struct proc *reap, *p2;
276 ksiginfo_t ksi;
277 struct reap_kill_tracker_head tracker;
278 struct reap_kill_tracker *t;
279 int error;
280
281 sx_assert(&proctree_lock, SX_LOCKED);
282 if (IN_CAPABILITY_MODE(td))
283 return (ECAPMODE);
284 if (rk->rk_sig <= 0 || rk->rk_sig > _SIG_MAXSIG ||
285 (rk->rk_flags & ~(REAPER_KILL_CHILDREN |
286 REAPER_KILL_SUBTREE)) != 0 || (rk->rk_flags &
287 (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE)) ==
288 (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE))
289 return (EINVAL);
290 PROC_UNLOCK(p);
291 reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
292 ksiginfo_init(&ksi);
293 ksi.ksi_signo = rk->rk_sig;
294 ksi.ksi_code = SI_USER;
295 ksi.ksi_pid = td->td_proc->p_pid;
296 ksi.ksi_uid = td->td_ucred->cr_ruid;
297 error = ESRCH;
298 rk->rk_killed = 0;
299 rk->rk_fpid = -1;
300 if ((rk->rk_flags & REAPER_KILL_CHILDREN) != 0) {
301 for (p2 = LIST_FIRST(&reap->p_children); p2 != NULL;
302 p2 = LIST_NEXT(p2, p_sibling)) {
303 reap_kill_proc(td, p2, &ksi, rk, &error);
304 /*
305 * Do not end the loop on error, signal
306 * everything we can.
307 */
308 }
309 } else {
310 TAILQ_INIT(&tracker);
311 reap_kill_sched(&tracker, reap);
312 while ((t = TAILQ_FIRST(&tracker)) != NULL) {
313 MPASS((t->parent->p_treeflag & P_TREE_REAPER) != 0);
314 TAILQ_REMOVE(&tracker, t, link);
315 for (p2 = LIST_FIRST(&t->parent->p_reaplist); p2 != NULL;
316 p2 = LIST_NEXT(p2, p_reapsibling)) {
317 if (t->parent == reap &&
318 (rk->rk_flags & REAPER_KILL_SUBTREE) != 0 &&
319 p2->p_reapsubtree != rk->rk_subtree)
320 continue;
321 if ((p2->p_treeflag & P_TREE_REAPER) != 0)
322 reap_kill_sched(&tracker, p2);
323 reap_kill_proc(td, p2, &ksi, rk, &error);
324 }
325 free(t, M_TEMP);
326 }
327 }
328 PROC_LOCK(p);
329 return (error);
330 }
331
332 static int
trace_ctl(struct thread * td,struct proc * p,int state)333 trace_ctl(struct thread *td, struct proc *p, int state)
334 {
335
336 PROC_LOCK_ASSERT(p, MA_OWNED);
337
338 /*
339 * Ktrace changes p_traceflag from or to zero under the
340 * process lock, so the test does not need to acquire ktrace
341 * mutex.
342 */
343 if ((p->p_flag & P_TRACED) != 0 || p->p_traceflag != 0)
344 return (EBUSY);
345
346 switch (state) {
347 case PROC_TRACE_CTL_ENABLE:
348 if (td->td_proc != p)
349 return (EPERM);
350 p->p_flag2 &= ~(P2_NOTRACE | P2_NOTRACE_EXEC);
351 break;
352 case PROC_TRACE_CTL_DISABLE_EXEC:
353 p->p_flag2 |= P2_NOTRACE_EXEC | P2_NOTRACE;
354 break;
355 case PROC_TRACE_CTL_DISABLE:
356 if ((p->p_flag2 & P2_NOTRACE_EXEC) != 0) {
357 KASSERT((p->p_flag2 & P2_NOTRACE) != 0,
358 ("dandling P2_NOTRACE_EXEC"));
359 if (td->td_proc != p)
360 return (EPERM);
361 p->p_flag2 &= ~P2_NOTRACE_EXEC;
362 } else {
363 p->p_flag2 |= P2_NOTRACE;
364 }
365 break;
366 default:
367 return (EINVAL);
368 }
369 return (0);
370 }
371
372 static int
trace_status(struct thread * td,struct proc * p,int * data)373 trace_status(struct thread *td, struct proc *p, int *data)
374 {
375
376 if ((p->p_flag2 & P2_NOTRACE) != 0) {
377 KASSERT((p->p_flag & P_TRACED) == 0,
378 ("%d traced but tracing disabled", p->p_pid));
379 *data = -1;
380 } else if ((p->p_flag & P_TRACED) != 0) {
381 *data = p->p_pptr->p_pid;
382 } else {
383 *data = 0;
384 }
385 return (0);
386 }
387
388 #ifndef _SYS_SYSPROTO_H_
389 struct procctl_args {
390 idtype_t idtype;
391 id_t id;
392 int com;
393 void *data;
394 };
395 #endif
396 /* ARGSUSED */
397 int
sys_procctl(struct thread * td,struct procctl_args * uap)398 sys_procctl(struct thread *td, struct procctl_args *uap)
399 {
400 void *data;
401 union {
402 struct procctl_reaper_status rs;
403 struct procctl_reaper_pids rp;
404 struct procctl_reaper_kill rk;
405 } x;
406 int error, error1, flags;
407
408 switch (uap->com) {
409 case PROC_SPROTECT:
410 case PROC_TRACE_CTL:
411 error = copyin(uap->data, &flags, sizeof(flags));
412 if (error != 0)
413 return (error);
414 data = &flags;
415 break;
416 case PROC_REAP_ACQUIRE:
417 case PROC_REAP_RELEASE:
418 if (uap->data != NULL)
419 return (EINVAL);
420 data = NULL;
421 break;
422 case PROC_REAP_STATUS:
423 data = &x.rs;
424 break;
425 case PROC_REAP_GETPIDS:
426 error = copyin(uap->data, &x.rp, sizeof(x.rp));
427 if (error != 0)
428 return (error);
429 data = &x.rp;
430 break;
431 case PROC_REAP_KILL:
432 error = copyin(uap->data, &x.rk, sizeof(x.rk));
433 if (error != 0)
434 return (error);
435 data = &x.rk;
436 break;
437 case PROC_TRACE_STATUS:
438 data = &flags;
439 break;
440 default:
441 return (EINVAL);
442 }
443 error = kern_procctl(td, uap->idtype, uap->id, uap->com, data);
444 switch (uap->com) {
445 case PROC_REAP_STATUS:
446 if (error == 0)
447 error = copyout(&x.rs, uap->data, sizeof(x.rs));
448 break;
449 case PROC_REAP_KILL:
450 error1 = copyout(&x.rk, uap->data, sizeof(x.rk));
451 if (error == 0)
452 error = error1;
453 break;
454 case PROC_TRACE_STATUS:
455 if (error == 0)
456 error = copyout(&flags, uap->data, sizeof(flags));
457 break;
458 }
459 return (error);
460 }
461
462 static int
kern_procctl_single(struct thread * td,struct proc * p,int com,void * data)463 kern_procctl_single(struct thread *td, struct proc *p, int com, void *data)
464 {
465
466 PROC_LOCK_ASSERT(p, MA_OWNED);
467 switch (com) {
468 case PROC_SPROTECT:
469 return (protect_set(td, p, *(int *)data));
470 case PROC_REAP_ACQUIRE:
471 return (reap_acquire(td, p));
472 case PROC_REAP_RELEASE:
473 return (reap_release(td, p));
474 case PROC_REAP_STATUS:
475 return (reap_status(td, p, data));
476 case PROC_REAP_GETPIDS:
477 return (reap_getpids(td, p, data));
478 case PROC_REAP_KILL:
479 return (reap_kill(td, p, data));
480 case PROC_TRACE_CTL:
481 return (trace_ctl(td, p, *(int *)data));
482 case PROC_TRACE_STATUS:
483 return (trace_status(td, p, data));
484 default:
485 return (EINVAL);
486 }
487 }
488
489 int
kern_procctl(struct thread * td,idtype_t idtype,id_t id,int com,void * data)490 kern_procctl(struct thread *td, idtype_t idtype, id_t id, int com, void *data)
491 {
492 struct pgrp *pg;
493 struct proc *p;
494 int error, first_error, ok;
495 bool tree_locked;
496
497 switch (com) {
498 case PROC_REAP_ACQUIRE:
499 case PROC_REAP_RELEASE:
500 case PROC_REAP_STATUS:
501 case PROC_REAP_GETPIDS:
502 case PROC_REAP_KILL:
503 case PROC_TRACE_STATUS:
504 if (idtype != P_PID)
505 return (EINVAL);
506 }
507
508 switch (com) {
509 case PROC_SPROTECT:
510 case PROC_REAP_STATUS:
511 case PROC_REAP_GETPIDS:
512 case PROC_REAP_KILL:
513 case PROC_TRACE_CTL:
514 sx_slock(&proctree_lock);
515 tree_locked = true;
516 break;
517 case PROC_REAP_ACQUIRE:
518 case PROC_REAP_RELEASE:
519 sx_xlock(&proctree_lock);
520 tree_locked = true;
521 break;
522 case PROC_TRACE_STATUS:
523 tree_locked = false;
524 break;
525 default:
526 return (EINVAL);
527 }
528
529 switch (idtype) {
530 case P_PID:
531 p = pfind(id);
532 if (p == NULL) {
533 error = ESRCH;
534 break;
535 }
536 error = p_cansee(td, p);
537 if (error == 0)
538 error = kern_procctl_single(td, p, com, data);
539 PROC_UNLOCK(p);
540 break;
541 case P_PGID:
542 /*
543 * Attempt to apply the operation to all members of the
544 * group. Ignore processes in the group that can't be
545 * seen. Ignore errors so long as at least one process is
546 * able to complete the request successfully.
547 */
548 pg = pgfind(id);
549 if (pg == NULL) {
550 error = ESRCH;
551 break;
552 }
553 PGRP_UNLOCK(pg);
554 ok = 0;
555 first_error = 0;
556 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
557 PROC_LOCK(p);
558 if (p->p_state == PRS_NEW || p_cansee(td, p) != 0) {
559 PROC_UNLOCK(p);
560 continue;
561 }
562 error = kern_procctl_single(td, p, com, data);
563 PROC_UNLOCK(p);
564 if (error == 0)
565 ok = 1;
566 else if (first_error == 0)
567 first_error = error;
568 }
569 if (ok)
570 error = 0;
571 else if (first_error != 0)
572 error = first_error;
573 else
574 /*
575 * Was not able to see any processes in the
576 * process group.
577 */
578 error = ESRCH;
579 break;
580 default:
581 error = EINVAL;
582 break;
583 }
584 if (tree_locked)
585 sx_unlock(&proctree_lock);
586 return (error);
587 }
588