1 /* 2 * Copyright (c) 2006,2017,2018 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 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 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 /* 35 * Copyright (c) 1982, 1986, 1991, 1993 36 * The Regents of the University of California. All rights reserved. 37 * (c) UNIX System Laboratories, Inc. 38 * All or some portions of this file are derived from material licensed 39 * to the University of California by American Telephone and Telegraph 40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 41 * the permission of UNIX System Laboratories, Inc. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)kern_resource.c 8.5 (Berkeley) 1/21/94 68 */ 69 #include <sys/resource.h> 70 #include <sys/spinlock.h> 71 #include <sys/proc.h> 72 #include <sys/priv.h> 73 #include <sys/file.h> 74 #include <sys/lockf.h> 75 #include <sys/kern_syscall.h> 76 #include <sys/malloc.h> 77 #include <sys/sysmsg.h> 78 79 #include <vm/vm_param.h> 80 #include <vm/vm.h> 81 #include <vm/vm_map.h> 82 83 #include <machine/pmap.h> 84 85 #include <sys/spinlock2.h> 86 87 static MALLOC_DEFINE(M_PLIMIT, "plimit", "resource limits"); 88 89 static void plimit_copy(struct plimit *olimit, struct plimit *nlimit); 90 91 static __inline 92 struct plimit * 93 readplimits(struct proc *p) 94 { 95 thread_t td = curthread; 96 struct plimit *limit; 97 98 limit = td->td_limit; 99 if (limit != p->p_limit) { 100 spin_lock_shared(&p->p_spin); 101 limit = p->p_limit; 102 atomic_add_int(&limit->p_refcnt, 1); 103 spin_unlock_shared(&p->p_spin); 104 if (td->td_limit) 105 plimit_free(td->td_limit); 106 td->td_limit = limit; 107 } 108 return limit; 109 } 110 111 /* 112 * Initialize proc0's plimit structure. All later plimit structures 113 * are inherited through fork. 114 */ 115 void 116 plimit_init0(struct plimit *limit) 117 { 118 int i; 119 rlim_t lim; 120 121 for (i = 0; i < RLIM_NLIMITS; ++i) { 122 limit->pl_rlimit[i].rlim_cur = RLIM_INFINITY; 123 limit->pl_rlimit[i].rlim_max = RLIM_INFINITY; 124 } 125 limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur = maxfiles; 126 limit->pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles; 127 limit->pl_rlimit[RLIMIT_NPROC].rlim_cur = maxproc; 128 limit->pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc; 129 lim = ptoa((rlim_t)vmstats.v_free_count); 130 limit->pl_rlimit[RLIMIT_RSS].rlim_max = lim; 131 limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim; 132 limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3; 133 limit->p_cpulimit = RLIM_INFINITY; 134 limit->p_refcnt = 1; 135 spin_init(&limit->p_spin, "plimitinit"); 136 } 137 138 /* 139 * Return a plimit for use by a new forked process given the one 140 * contained in the parent process. 141 */ 142 struct plimit * 143 plimit_fork(struct proc *p1) 144 { 145 struct plimit *olimit = p1->p_limit; 146 struct plimit *nlimit; 147 uint32_t count; 148 149 /* 150 * Try to share the parent's plimit structure. If we cannot, make 151 * a copy. 152 * 153 * NOTE: (count) value is field prior to increment. 154 */ 155 count = atomic_fetchadd_int(&olimit->p_refcnt, 1); 156 cpu_ccfence(); 157 if (count & PLIMITF_EXCLUSIVE) { 158 if ((count & PLIMITF_MASK) == 1 && p1->p_nthreads == 1) { 159 atomic_clear_int(&olimit->p_refcnt, PLIMITF_EXCLUSIVE); 160 } else { 161 nlimit = kmalloc(sizeof(*nlimit), M_PLIMIT, M_WAITOK); 162 plimit_copy(olimit, nlimit); 163 plimit_free(olimit); 164 olimit = nlimit; 165 } 166 } 167 return olimit; 168 } 169 170 /* 171 * This routine is called when a new LWP is created for a process. We 172 * must force exclusivity to ensure that p->p_limit remains stable. 173 * 174 * LWPs share the same process structure so this does not bump refcnt. 175 */ 176 void 177 plimit_lwp_fork(struct proc *p) 178 { 179 struct plimit *olimit = p->p_limit; 180 struct plimit *nlimit; 181 uint32_t count; 182 183 count = olimit->p_refcnt; 184 cpu_ccfence(); 185 if ((count & PLIMITF_EXCLUSIVE) == 0) { 186 if (count != 1) { 187 nlimit = kmalloc(sizeof(*nlimit), M_PLIMIT, M_WAITOK); 188 plimit_copy(olimit, nlimit); 189 p->p_limit = nlimit; 190 plimit_free(olimit); 191 olimit = nlimit; 192 } 193 atomic_set_int(&olimit->p_refcnt, PLIMITF_EXCLUSIVE); 194 } 195 } 196 197 /* 198 * This routine is called to fixup a process's p_limit structure prior 199 * to it being modified. If index >= 0 the specified modification is also 200 * made. 201 * 202 * This routine must make the limit structure exclusive. If we are threaded, 203 * the structure will already be exclusive. A later fork will convert it 204 * back to copy-on-write if possible. 205 * 206 * We can count on p->p_limit being stable since if we had created any 207 * threads it will have already been made exclusive. 208 */ 209 void 210 plimit_modify(struct proc *p, int index, struct rlimit *rlim) 211 { 212 struct plimit *olimit; 213 struct plimit *nlimit; 214 uint32_t count; 215 216 /* 217 * Make exclusive 218 */ 219 olimit = p->p_limit; 220 count = olimit->p_refcnt; 221 cpu_ccfence(); 222 if ((count & PLIMITF_EXCLUSIVE) == 0) { 223 if (count != 1) { 224 nlimit = kmalloc(sizeof(*nlimit), M_PLIMIT, M_WAITOK); 225 plimit_copy(olimit, nlimit); 226 p->p_limit = nlimit; 227 plimit_free(olimit); 228 olimit = nlimit; 229 } 230 atomic_set_int(&olimit->p_refcnt, PLIMITF_EXCLUSIVE); 231 } 232 233 /* 234 * Make modification 235 */ 236 if (index >= 0) { 237 if (p->p_nthreads == 1) { 238 p->p_limit->pl_rlimit[index] = *rlim; 239 } else { 240 spin_lock(&olimit->p_spin); 241 p->p_limit->pl_rlimit[index].rlim_cur = rlim->rlim_cur; 242 p->p_limit->pl_rlimit[index].rlim_max = rlim->rlim_max; 243 spin_unlock(&olimit->p_spin); 244 } 245 } 246 } 247 248 /* 249 * Destroy a process's plimit structure. 250 */ 251 void 252 plimit_free(struct plimit *limit) 253 { 254 uint32_t count; 255 256 count = atomic_fetchadd_int(&limit->p_refcnt, -1); 257 258 if ((count & ~PLIMITF_EXCLUSIVE) == 1) { 259 limit->p_refcnt = -999; 260 kfree(limit, M_PLIMIT); 261 } 262 } 263 264 /* 265 * Modify a resource limit (from system call) 266 */ 267 int 268 kern_setrlimit(u_int which, struct rlimit *limp) 269 { 270 struct proc *p = curproc; 271 struct plimit *limit; 272 struct rlimit *alimp; 273 int error; 274 275 if (which >= RLIM_NLIMITS) 276 return (EINVAL); 277 278 /* 279 * We will be modifying a resource, make a copy if necessary. 280 */ 281 plimit_modify(p, -1, NULL); 282 limit = p->p_limit; 283 alimp = &limit->pl_rlimit[which]; 284 285 /* 286 * Preserve historical bugs by treating negative limits as unsigned. 287 */ 288 if (limp->rlim_cur < 0) 289 limp->rlim_cur = RLIM_INFINITY; 290 if (limp->rlim_max < 0) 291 limp->rlim_max = RLIM_INFINITY; 292 293 spin_lock(&limit->p_spin); 294 if (limp->rlim_cur > alimp->rlim_max || 295 limp->rlim_max > alimp->rlim_max) { 296 spin_unlock(&limit->p_spin); 297 error = priv_check_cred(p->p_ucred, PRIV_PROC_SETRLIMIT, 0); 298 if (error) 299 return (error); 300 } else { 301 spin_unlock(&limit->p_spin); 302 } 303 if (limp->rlim_cur > limp->rlim_max) 304 limp->rlim_cur = limp->rlim_max; 305 306 switch (which) { 307 case RLIMIT_CPU: 308 spin_lock(&limit->p_spin); 309 if (limp->rlim_cur > RLIM_INFINITY / (rlim_t)1000000) 310 limit->p_cpulimit = RLIM_INFINITY; 311 else 312 limit->p_cpulimit = (rlim_t)1000000 * limp->rlim_cur; 313 spin_unlock(&limit->p_spin); 314 break; 315 case RLIMIT_DATA: 316 if (limp->rlim_cur > maxdsiz) 317 limp->rlim_cur = maxdsiz; 318 if (limp->rlim_max > maxdsiz) 319 limp->rlim_max = maxdsiz; 320 break; 321 322 case RLIMIT_STACK: 323 if (limp->rlim_cur > maxssiz) 324 limp->rlim_cur = maxssiz; 325 if (limp->rlim_max > maxssiz) 326 limp->rlim_max = maxssiz; 327 /* 328 * Stack is allocated to the max at exec time with only 329 * "rlim_cur" bytes accessible. If stack limit is going 330 * up make more accessible, if going down make inaccessible. 331 */ 332 spin_lock(&limit->p_spin); 333 if (limp->rlim_cur != alimp->rlim_cur) { 334 vm_offset_t addr; 335 vm_size_t size; 336 vm_prot_t prot; 337 338 if (limp->rlim_cur > alimp->rlim_cur) { 339 prot = VM_PROT_ALL; 340 size = limp->rlim_cur - alimp->rlim_cur; 341 addr = USRSTACK - limp->rlim_cur; 342 } else { 343 prot = VM_PROT_NONE; 344 size = alimp->rlim_cur - limp->rlim_cur; 345 addr = USRSTACK - alimp->rlim_cur; 346 } 347 spin_unlock(&limit->p_spin); 348 addr = trunc_page(addr); 349 size = round_page(size); 350 vm_map_protect(&p->p_vmspace->vm_map, 351 addr, addr+size, prot, FALSE); 352 } else { 353 spin_unlock(&limit->p_spin); 354 } 355 break; 356 357 case RLIMIT_NOFILE: 358 if (limp->rlim_cur > maxfilesperproc) 359 limp->rlim_cur = maxfilesperproc; 360 if (limp->rlim_max > maxfilesperproc) 361 limp->rlim_max = maxfilesperproc; 362 break; 363 364 case RLIMIT_NPROC: 365 if (limp->rlim_cur > maxprocperuid) 366 limp->rlim_cur = maxprocperuid; 367 if (limp->rlim_max > maxprocperuid) 368 limp->rlim_max = maxprocperuid; 369 if (limp->rlim_cur < 1) 370 limp->rlim_cur = 1; 371 if (limp->rlim_max < 1) 372 limp->rlim_max = 1; 373 break; 374 case RLIMIT_POSIXLOCKS: 375 if (limp->rlim_cur > maxposixlocksperuid) 376 limp->rlim_cur = maxposixlocksperuid; 377 if (limp->rlim_max > maxposixlocksperuid) 378 limp->rlim_max = maxposixlocksperuid; 379 break; 380 } 381 spin_lock(&limit->p_spin); 382 *alimp = *limp; 383 spin_unlock(&limit->p_spin); 384 return (0); 385 } 386 387 int 388 sys_setrlimit(struct sysmsg *sysmsg, const struct __setrlimit_args *uap) 389 { 390 struct rlimit alim; 391 int error; 392 393 error = copyin(uap->rlp, &alim, sizeof(alim)); 394 if (error) 395 return (error); 396 397 error = kern_setrlimit(uap->which, &alim); 398 399 return (error); 400 } 401 402 /* 403 * The rlimit indexed by which is returned in the second argument. 404 */ 405 int 406 kern_getrlimit(u_int which, struct rlimit *limp) 407 { 408 struct proc *p = curproc; 409 struct plimit *limit; 410 411 /* 412 * p is NULL when kern_getrlimit is called from a 413 * kernel thread. In this case as the calling proc 414 * isn't available we just skip the limit check. 415 */ 416 if (p == NULL) 417 return 0; 418 419 if (which >= RLIM_NLIMITS) 420 return (EINVAL); 421 422 limit = readplimits(p); 423 *limp = limit->pl_rlimit[which]; 424 425 return (0); 426 } 427 428 int 429 sys_getrlimit(struct sysmsg *sysmsg, const struct __getrlimit_args *uap) 430 { 431 struct rlimit lim; 432 int error; 433 434 error = kern_getrlimit(uap->which, &lim); 435 436 if (error == 0) 437 error = copyout(&lim, uap->rlp, sizeof(*uap->rlp)); 438 return error; 439 } 440 441 /* 442 * Determine if the cpu limit has been reached and return an operations 443 * code for the caller to perform. 444 */ 445 int 446 plimit_testcpulimit(struct proc *p, u_int64_t ttime) 447 { 448 struct plimit *limit; 449 struct rlimit *rlim; 450 int mode; 451 452 limit = readplimits(p); 453 454 /* 455 * Initial tests without the spinlock. This is the fast path. 456 * Any 32/64 bit glitches will fall through and retest with 457 * the spinlock. 458 */ 459 if (limit->p_cpulimit == RLIM_INFINITY) 460 return(PLIMIT_TESTCPU_OK); 461 if (ttime <= limit->p_cpulimit) 462 return(PLIMIT_TESTCPU_OK); 463 464 if (ttime > limit->p_cpulimit) { 465 rlim = &limit->pl_rlimit[RLIMIT_CPU]; 466 if (ttime / (rlim_t)1000000 >= rlim->rlim_max + 5) 467 mode = PLIMIT_TESTCPU_KILL; 468 else 469 mode = PLIMIT_TESTCPU_XCPU; 470 } else { 471 mode = PLIMIT_TESTCPU_OK; 472 } 473 474 return(mode); 475 } 476 477 /* 478 * Helper routine to copy olimit to nlimit and initialize nlimit for 479 * use. nlimit's reference count will be set to 1 and its exclusive bit 480 * will be cleared. 481 */ 482 static 483 void 484 plimit_copy(struct plimit *olimit, struct plimit *nlimit) 485 { 486 *nlimit = *olimit; 487 488 spin_init(&nlimit->p_spin, "plimitcopy"); 489 nlimit->p_refcnt = 1; 490 } 491 492 /* 493 * This routine returns the value of a resource, downscaled based on 494 * the processes fork depth and chroot depth (up to 50%). This mechanism 495 * is designed to prevent run-aways from blowing up unrelated processes 496 * running under the same UID. 497 * 498 * NOTE: Currently only applicable to RLIMIT_NPROC. We could also limit 499 * file descriptors but we shouldn't have to as these are allocated 500 * dynamically. 501 */ 502 u_int64_t 503 plimit_getadjvalue(int i) 504 { 505 struct proc *p = curproc; 506 struct plimit *limit; 507 uint64_t v; 508 uint32_t depth; 509 510 limit = p->p_limit; 511 v = limit->pl_rlimit[i].rlim_cur; 512 if (i == RLIMIT_NPROC) { 513 /* 514 * 10% per chroot (around 1/3% per fork depth), with a 515 * maximum of 50% downscaling of the resource limit. 516 */ 517 depth = p->p_depth; 518 if (depth > 32 * 5) 519 depth = 32 * 5; 520 v -= v * depth / 320; 521 } 522 return v; 523 } 524