Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_procctl.c
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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: releng/10.2/sys/kern/kern_procctl.c 278949 2015-02-18 08:10:13Z 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 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 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 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 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 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 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 KASSERT(LIST_EMPTY(&reap->p_reaplist), ("reap children list")); 191 KASSERT(LIST_EMPTY(&reap->p_children), ("children list")); 192 } 193 return (0); 194 } 195 196 static int 197 reap_getpids(struct thread *td, struct proc *p, struct procctl_reaper_pids *rp) 198 { 199 struct proc *reap, *p2; 200 struct procctl_reaper_pidinfo *pi, *pip; 201 u_int i, n; 202 int error; 203 204 sx_assert(&proctree_lock, SX_LOCKED); 205 PROC_UNLOCK(p); 206 reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p; 207 n = i = 0; 208 error = 0; 209 LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) 210 n++; 211 sx_unlock(&proctree_lock); 212 if (rp->rp_count < n) 213 n = rp->rp_count; 214 pi = malloc(n * sizeof(*pi), M_TEMP, M_WAITOK); 215 sx_slock(&proctree_lock); 216 LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) { 217 if (i == n) 218 break; 219 pip = &pi[i]; 220 bzero(pip, sizeof(*pip)); 221 pip->pi_pid = p2->p_pid; 222 pip->pi_subtree = p2->p_reapsubtree; 223 pip->pi_flags = REAPER_PIDINFO_VALID; 224 if (proc_realparent(p2) == reap) 225 pip->pi_flags |= REAPER_PIDINFO_CHILD; 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 int 237 reap_kill(struct thread *td, struct proc *p, struct procctl_reaper_kill *rk) 238 { 239 struct proc *reap, *p2; 240 ksiginfo_t ksi; 241 int error, error1; 242 243 sx_assert(&proctree_lock, SX_LOCKED); 244 if (IN_CAPABILITY_MODE(td)) 245 return (ECAPMODE); 246 if (rk->rk_sig <= 0 || rk->rk_sig > _SIG_MAXSIG) 247 return (EINVAL); 248 if ((rk->rk_flags & ~REAPER_KILL_CHILDREN) != 0) 249 return (EINVAL); 250 PROC_UNLOCK(p); 251 reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p; 252 ksiginfo_init(&ksi); 253 ksi.ksi_signo = rk->rk_sig; 254 ksi.ksi_code = SI_USER; 255 ksi.ksi_pid = td->td_proc->p_pid; 256 ksi.ksi_uid = td->td_ucred->cr_ruid; 257 error = ESRCH; 258 rk->rk_killed = 0; 259 rk->rk_fpid = -1; 260 for (p2 = (rk->rk_flags & REAPER_KILL_CHILDREN) != 0 ? 261 LIST_FIRST(&reap->p_children) : LIST_FIRST(&reap->p_reaplist); 262 p2 != NULL; 263 p2 = (rk->rk_flags & REAPER_KILL_CHILDREN) != 0 ? 264 LIST_NEXT(p2, p_sibling) : LIST_NEXT(p2, p_reapsibling)) { 265 if ((rk->rk_flags & REAPER_KILL_SUBTREE) != 0 && 266 p2->p_reapsubtree != rk->rk_subtree) 267 continue; 268 PROC_LOCK(p2); 269 error1 = p_cansignal(td, p2, rk->rk_sig); 270 if (error1 == 0) { 271 pksignal(p2, rk->rk_sig, &ksi); 272 rk->rk_killed++; 273 error = error1; 274 } else if (error == ESRCH) { 275 error = error1; 276 rk->rk_fpid = p2->p_pid; 277 } 278 PROC_UNLOCK(p2); 279 /* Do not end the loop on error, signal everything we can. */ 280 } 281 PROC_LOCK(p); 282 return (error); 283 } 284 285 static int 286 trace_ctl(struct thread *td, struct proc *p, int state) 287 { 288 289 PROC_LOCK_ASSERT(p, MA_OWNED); 290 291 /* 292 * Ktrace changes p_traceflag from or to zero under the 293 * process lock, so the test does not need to acquire ktrace 294 * mutex. 295 */ 296 if ((p->p_flag & P_TRACED) != 0 || p->p_traceflag != 0) 297 return (EBUSY); 298 299 switch (state) { 300 case PROC_TRACE_CTL_ENABLE: 301 if (td->td_proc != p) 302 return (EPERM); 303 p->p_flag2 &= ~(P2_NOTRACE | P2_NOTRACE_EXEC); 304 break; 305 case PROC_TRACE_CTL_DISABLE_EXEC: 306 p->p_flag2 |= P2_NOTRACE_EXEC | P2_NOTRACE; 307 break; 308 case PROC_TRACE_CTL_DISABLE: 309 if ((p->p_flag2 & P2_NOTRACE_EXEC) != 0) { 310 KASSERT((p->p_flag2 & P2_NOTRACE) != 0, 311 ("dandling P2_NOTRACE_EXEC")); 312 if (td->td_proc != p) 313 return (EPERM); 314 p->p_flag2 &= ~P2_NOTRACE_EXEC; 315 } else { 316 p->p_flag2 |= P2_NOTRACE; 317 } 318 break; 319 default: 320 return (EINVAL); 321 } 322 return (0); 323 } 324 325 static int 326 trace_status(struct thread *td, struct proc *p, int *data) 327 { 328 329 if ((p->p_flag2 & P2_NOTRACE) != 0) { 330 KASSERT((p->p_flag & P_TRACED) == 0, 331 ("%d traced but tracing disabled", p->p_pid)); 332 *data = -1; 333 } else if ((p->p_flag & P_TRACED) != 0) { 334 *data = p->p_pptr->p_pid; 335 } else { 336 *data = 0; 337 } 338 return (0); 339 } 340 341 #ifndef _SYS_SYSPROTO_H_ 342 struct procctl_args { 343 idtype_t idtype; 344 id_t id; 345 int com; 346 void *data; 347 }; 348 #endif 349 /* ARGSUSED */ 350 int 351 sys_procctl(struct thread *td, struct procctl_args *uap) 352 { 353 void *data; 354 union { 355 struct procctl_reaper_status rs; 356 struct procctl_reaper_pids rp; 357 struct procctl_reaper_kill rk; 358 } x; 359 int error, error1, flags; 360 361 switch (uap->com) { 362 case PROC_SPROTECT: 363 case PROC_TRACE_CTL: 364 error = copyin(uap->data, &flags, sizeof(flags)); 365 if (error != 0) 366 return (error); 367 data = &flags; 368 break; 369 case PROC_REAP_ACQUIRE: 370 case PROC_REAP_RELEASE: 371 if (uap->data != NULL) 372 return (EINVAL); 373 data = NULL; 374 break; 375 case PROC_REAP_STATUS: 376 data = &x.rs; 377 break; 378 case PROC_REAP_GETPIDS: 379 error = copyin(uap->data, &x.rp, sizeof(x.rp)); 380 if (error != 0) 381 return (error); 382 data = &x.rp; 383 break; 384 case PROC_REAP_KILL: 385 error = copyin(uap->data, &x.rk, sizeof(x.rk)); 386 if (error != 0) 387 return (error); 388 data = &x.rk; 389 break; 390 case PROC_TRACE_STATUS: 391 data = &flags; 392 break; 393 default: 394 return (EINVAL); 395 } 396 error = kern_procctl(td, uap->idtype, uap->id, uap->com, data); 397 switch (uap->com) { 398 case PROC_REAP_STATUS: 399 if (error == 0) 400 error = copyout(&x.rs, uap->data, sizeof(x.rs)); 401 break; 402 case PROC_REAP_KILL: 403 error1 = copyout(&x.rk, uap->data, sizeof(x.rk)); 404 if (error == 0) 405 error = error1; 406 break; 407 case PROC_TRACE_STATUS: 408 if (error == 0) 409 error = copyout(&flags, uap->data, sizeof(flags)); 410 break; 411 } 412 return (error); 413 } 414 415 static int 416 kern_procctl_single(struct thread *td, struct proc *p, int com, void *data) 417 { 418 419 PROC_LOCK_ASSERT(p, MA_OWNED); 420 switch (com) { 421 case PROC_SPROTECT: 422 return (protect_set(td, p, *(int *)data)); 423 case PROC_REAP_ACQUIRE: 424 return (reap_acquire(td, p)); 425 case PROC_REAP_RELEASE: 426 return (reap_release(td, p)); 427 case PROC_REAP_STATUS: 428 return (reap_status(td, p, data)); 429 case PROC_REAP_GETPIDS: 430 return (reap_getpids(td, p, data)); 431 case PROC_REAP_KILL: 432 return (reap_kill(td, p, data)); 433 case PROC_TRACE_CTL: 434 return (trace_ctl(td, p, *(int *)data)); 435 case PROC_TRACE_STATUS: 436 return (trace_status(td, p, data)); 437 default: 438 return (EINVAL); 439 } 440 } 441 442 int 443 kern_procctl(struct thread *td, idtype_t idtype, id_t id, int com, void *data) 444 { 445 struct pgrp *pg; 446 struct proc *p; 447 int error, first_error, ok; 448 bool tree_locked; 449 450 switch (com) { 451 case PROC_REAP_ACQUIRE: 452 case PROC_REAP_RELEASE: 453 case PROC_REAP_STATUS: 454 case PROC_REAP_GETPIDS: 455 case PROC_REAP_KILL: 456 case PROC_TRACE_STATUS: 457 if (idtype != P_PID) 458 return (EINVAL); 459 } 460 461 switch (com) { 462 case PROC_SPROTECT: 463 case PROC_REAP_STATUS: 464 case PROC_REAP_GETPIDS: 465 case PROC_REAP_KILL: 466 case PROC_TRACE_CTL: 467 sx_slock(&proctree_lock); 468 tree_locked = true; 469 break; 470 case PROC_REAP_ACQUIRE: 471 case PROC_REAP_RELEASE: 472 sx_xlock(&proctree_lock); 473 tree_locked = true; 474 break; 475 case PROC_TRACE_STATUS: 476 tree_locked = false; 477 break; 478 default: 479 return (EINVAL); 480 } 481 482 switch (idtype) { 483 case P_PID: 484 p = pfind(id); 485 if (p == NULL) { 486 error = ESRCH; 487 break; 488 } 489 error = p_cansee(td, p); 490 if (error == 0) 491 error = kern_procctl_single(td, p, com, data); 492 PROC_UNLOCK(p); 493 break; 494 case P_PGID: 495 /* 496 * Attempt to apply the operation to all members of the 497 * group. Ignore processes in the group that can't be 498 * seen. Ignore errors so long as at least one process is 499 * able to complete the request successfully. 500 */ 501 pg = pgfind(id); 502 if (pg == NULL) { 503 error = ESRCH; 504 break; 505 } 506 PGRP_UNLOCK(pg); 507 ok = 0; 508 first_error = 0; 509 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 510 PROC_LOCK(p); 511 if (p->p_state == PRS_NEW || p_cansee(td, p) != 0) { 512 PROC_UNLOCK(p); 513 continue; 514 } 515 error = kern_procctl_single(td, p, com, data); 516 PROC_UNLOCK(p); 517 if (error == 0) 518 ok = 1; 519 else if (first_error == 0) 520 first_error = error; 521 } 522 if (ok) 523 error = 0; 524 else if (first_error != 0) 525 error = first_error; 526 else 527 /* 528 * Was not able to see any processes in the 529 * process group. 530 */ 531 error = ESRCH; 532 break; 533 default: 534 error = EINVAL; 535 break; 536 } 537 if (tree_locked) 538 sx_unlock(&proctree_lock); 539 return (error); 540 }
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