kern_procctl.c revision 313303
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 313303 2017-02-05 21:31:40Z jilles $"); 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 46static int 47protect_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 64static int 65protect_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 98static int 99protect_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 127static int 128reap_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 144static int 145reap_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 159static int 160reap_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 194static int 195reap_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 i++; 225 } 226 sx_sunlock(&proctree_lock); 227 error = copyout(pi, rp->rp_pids, i * sizeof(*pi)); 228 free(pi, M_TEMP); 229 sx_slock(&proctree_lock); 230 PROC_LOCK(p); 231 return (error); 232} 233 234static int 235reap_kill(struct thread *td, struct proc *p, struct procctl_reaper_kill *rk) 236{ 237 struct proc *reap, *p2; 238 ksiginfo_t ksi; 239 int error, error1; 240 241 sx_assert(&proctree_lock, SX_LOCKED); 242 if (IN_CAPABILITY_MODE(td)) 243 return (ECAPMODE); 244 if (rk->rk_sig <= 0 || rk->rk_sig > _SIG_MAXSIG) 245 return (EINVAL); 246 if ((rk->rk_flags & ~(REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE)) != 0) 247 return (EINVAL); 248 PROC_UNLOCK(p); 249 reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p; 250 ksiginfo_init(&ksi); 251 ksi.ksi_signo = rk->rk_sig; 252 ksi.ksi_code = SI_USER; 253 ksi.ksi_pid = td->td_proc->p_pid; 254 ksi.ksi_uid = td->td_ucred->cr_ruid; 255 error = ESRCH; 256 rk->rk_killed = 0; 257 rk->rk_fpid = -1; 258 for (p2 = (rk->rk_flags & REAPER_KILL_CHILDREN) != 0 ? 259 LIST_FIRST(&reap->p_children) : LIST_FIRST(&reap->p_reaplist); 260 p2 != NULL; 261 p2 = (rk->rk_flags & REAPER_KILL_CHILDREN) != 0 ? 262 LIST_NEXT(p2, p_sibling) : LIST_NEXT(p2, p_reapsibling)) { 263 if ((rk->rk_flags & REAPER_KILL_SUBTREE) != 0 && 264 p2->p_reapsubtree != rk->rk_subtree) 265 continue; 266 PROC_LOCK(p2); 267 error1 = p_cansignal(td, p2, rk->rk_sig); 268 if (error1 == 0) { 269 pksignal(p2, rk->rk_sig, &ksi); 270 rk->rk_killed++; 271 error = error1; 272 } else if (error == ESRCH) { 273 error = error1; 274 rk->rk_fpid = p2->p_pid; 275 } 276 PROC_UNLOCK(p2); 277 /* Do not end the loop on error, signal everything we can. */ 278 } 279 PROC_LOCK(p); 280 return (error); 281} 282 283static int 284trace_ctl(struct thread *td, struct proc *p, int state) 285{ 286 287 PROC_LOCK_ASSERT(p, MA_OWNED); 288 289 /* 290 * Ktrace changes p_traceflag from or to zero under the 291 * process lock, so the test does not need to acquire ktrace 292 * mutex. 293 */ 294 if ((p->p_flag & P_TRACED) != 0 || p->p_traceflag != 0) 295 return (EBUSY); 296 297 switch (state) { 298 case PROC_TRACE_CTL_ENABLE: 299 if (td->td_proc != p) 300 return (EPERM); 301 p->p_flag2 &= ~(P2_NOTRACE | P2_NOTRACE_EXEC); 302 break; 303 case PROC_TRACE_CTL_DISABLE_EXEC: 304 p->p_flag2 |= P2_NOTRACE_EXEC | P2_NOTRACE; 305 break; 306 case PROC_TRACE_CTL_DISABLE: 307 if ((p->p_flag2 & P2_NOTRACE_EXEC) != 0) { 308 KASSERT((p->p_flag2 & P2_NOTRACE) != 0, 309 ("dandling P2_NOTRACE_EXEC")); 310 if (td->td_proc != p) 311 return (EPERM); 312 p->p_flag2 &= ~P2_NOTRACE_EXEC; 313 } else { 314 p->p_flag2 |= P2_NOTRACE; 315 } 316 break; 317 default: 318 return (EINVAL); 319 } 320 return (0); 321} 322 323static int 324trace_status(struct thread *td, struct proc *p, int *data) 325{ 326 327 if ((p->p_flag2 & P2_NOTRACE) != 0) { 328 KASSERT((p->p_flag & P_TRACED) == 0, 329 ("%d traced but tracing disabled", p->p_pid)); 330 *data = -1; 331 } else if ((p->p_flag & P_TRACED) != 0) { 332 *data = p->p_pptr->p_pid; 333 } else { 334 *data = 0; 335 } 336 return (0); 337} 338 339#ifndef _SYS_SYSPROTO_H_ 340struct procctl_args { 341 idtype_t idtype; 342 id_t id; 343 int com; 344 void *data; 345}; 346#endif 347/* ARGSUSED */ 348int 349sys_procctl(struct thread *td, struct procctl_args *uap) 350{ 351 void *data; 352 union { 353 struct procctl_reaper_status rs; 354 struct procctl_reaper_pids rp; 355 struct procctl_reaper_kill rk; 356 } x; 357 int error, error1, flags; 358 359 switch (uap->com) { 360 case PROC_SPROTECT: 361 case PROC_TRACE_CTL: 362 error = copyin(uap->data, &flags, sizeof(flags)); 363 if (error != 0) 364 return (error); 365 data = &flags; 366 break; 367 case PROC_REAP_ACQUIRE: 368 case PROC_REAP_RELEASE: 369 if (uap->data != NULL) 370 return (EINVAL); 371 data = NULL; 372 break; 373 case PROC_REAP_STATUS: 374 data = &x.rs; 375 break; 376 case PROC_REAP_GETPIDS: 377 error = copyin(uap->data, &x.rp, sizeof(x.rp)); 378 if (error != 0) 379 return (error); 380 data = &x.rp; 381 break; 382 case PROC_REAP_KILL: 383 error = copyin(uap->data, &x.rk, sizeof(x.rk)); 384 if (error != 0) 385 return (error); 386 data = &x.rk; 387 break; 388 case PROC_TRACE_STATUS: 389 data = &flags; 390 break; 391 default: 392 return (EINVAL); 393 } 394 error = kern_procctl(td, uap->idtype, uap->id, uap->com, data); 395 switch (uap->com) { 396 case PROC_REAP_STATUS: 397 if (error == 0) 398 error = copyout(&x.rs, uap->data, sizeof(x.rs)); 399 break; 400 case PROC_REAP_KILL: 401 error1 = copyout(&x.rk, uap->data, sizeof(x.rk)); 402 if (error == 0) 403 error = error1; 404 break; 405 case PROC_TRACE_STATUS: 406 if (error == 0) 407 error = copyout(&flags, uap->data, sizeof(flags)); 408 break; 409 } 410 return (error); 411} 412 413static int 414kern_procctl_single(struct thread *td, struct proc *p, int com, void *data) 415{ 416 417 PROC_LOCK_ASSERT(p, MA_OWNED); 418 switch (com) { 419 case PROC_SPROTECT: 420 return (protect_set(td, p, *(int *)data)); 421 case PROC_REAP_ACQUIRE: 422 return (reap_acquire(td, p)); 423 case PROC_REAP_RELEASE: 424 return (reap_release(td, p)); 425 case PROC_REAP_STATUS: 426 return (reap_status(td, p, data)); 427 case PROC_REAP_GETPIDS: 428 return (reap_getpids(td, p, data)); 429 case PROC_REAP_KILL: 430 return (reap_kill(td, p, data)); 431 case PROC_TRACE_CTL: 432 return (trace_ctl(td, p, *(int *)data)); 433 case PROC_TRACE_STATUS: 434 return (trace_status(td, p, data)); 435 default: 436 return (EINVAL); 437 } 438} 439 440int 441kern_procctl(struct thread *td, idtype_t idtype, id_t id, int com, void *data) 442{ 443 struct pgrp *pg; 444 struct proc *p; 445 int error, first_error, ok; 446 bool tree_locked; 447 448 switch (com) { 449 case PROC_REAP_ACQUIRE: 450 case PROC_REAP_RELEASE: 451 case PROC_REAP_STATUS: 452 case PROC_REAP_GETPIDS: 453 case PROC_REAP_KILL: 454 case PROC_TRACE_STATUS: 455 if (idtype != P_PID) 456 return (EINVAL); 457 } 458 459 switch (com) { 460 case PROC_SPROTECT: 461 case PROC_REAP_STATUS: 462 case PROC_REAP_GETPIDS: 463 case PROC_REAP_KILL: 464 case PROC_TRACE_CTL: 465 sx_slock(&proctree_lock); 466 tree_locked = true; 467 break; 468 case PROC_REAP_ACQUIRE: 469 case PROC_REAP_RELEASE: 470 sx_xlock(&proctree_lock); 471 tree_locked = true; 472 break; 473 case PROC_TRACE_STATUS: 474 tree_locked = false; 475 break; 476 default: 477 return (EINVAL); 478 } 479 480 switch (idtype) { 481 case P_PID: 482 p = pfind(id); 483 if (p == NULL) { 484 error = ESRCH; 485 break; 486 } 487 error = p_cansee(td, p); 488 if (error == 0) 489 error = kern_procctl_single(td, p, com, data); 490 PROC_UNLOCK(p); 491 break; 492 case P_PGID: 493 /* 494 * Attempt to apply the operation to all members of the 495 * group. Ignore processes in the group that can't be 496 * seen. Ignore errors so long as at least one process is 497 * able to complete the request successfully. 498 */ 499 pg = pgfind(id); 500 if (pg == NULL) { 501 error = ESRCH; 502 break; 503 } 504 PGRP_UNLOCK(pg); 505 ok = 0; 506 first_error = 0; 507 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 508 PROC_LOCK(p); 509 if (p->p_state == PRS_NEW || p_cansee(td, p) != 0) { 510 PROC_UNLOCK(p); 511 continue; 512 } 513 error = kern_procctl_single(td, p, com, data); 514 PROC_UNLOCK(p); 515 if (error == 0) 516 ok = 1; 517 else if (first_error == 0) 518 first_error = error; 519 } 520 if (ok) 521 error = 0; 522 else if (first_error != 0) 523 error = first_error; 524 else 525 /* 526 * Was not able to see any processes in the 527 * process group. 528 */ 529 error = ESRCH; 530 break; 531 default: 532 error = EINVAL; 533 break; 534 } 535 if (tree_locked) 536 sx_unlock(&proctree_lock); 537 return (error); 538} 539