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 78 #include <vm/vm_param.h> 79 #include <vm/vm.h> 80 #include <vm/vm_map.h> 81 82 #include <machine/pmap.h> 83 84 #include <sys/spinlock2.h> 85 86 static MALLOC_DEFINE(M_PLIMIT, "plimit", "resource limits"); 87 88 static void plimit_copy(struct plimit *olimit, struct plimit *nlimit); 89 90 static __inline 91 struct plimit * 92 readplimits(struct proc *p) 93 { 94 thread_t td = curthread; 95 struct plimit *limit; 96 97 limit = td->td_limit; 98 if (limit != p->p_limit) { 99 spin_lock_shared(&p->p_spin); 100 limit = p->p_limit; 101 atomic_add_int(&limit->p_refcnt, 1); 102 spin_unlock_shared(&p->p_spin); 103 if (td->td_limit) 104 plimit_free(td->td_limit); 105 td->td_limit = limit; 106 } 107 return limit; 108 } 109 110 /* 111 * Initialize proc0's plimit structure. All later plimit structures 112 * are inherited through fork. 113 */ 114 void 115 plimit_init0(struct plimit *limit) 116 { 117 int i; 118 rlim_t lim; 119 120 for (i = 0; i < RLIM_NLIMITS; ++i) { 121 limit->pl_rlimit[i].rlim_cur = RLIM_INFINITY; 122 limit->pl_rlimit[i].rlim_max = RLIM_INFINITY; 123 } 124 limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur = maxfiles; 125 limit->pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles; 126 limit->pl_rlimit[RLIMIT_NPROC].rlim_cur = maxproc; 127 limit->pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc; 128 lim = ptoa((rlim_t)vmstats.v_free_count); 129 limit->pl_rlimit[RLIMIT_RSS].rlim_max = lim; 130 limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim; 131 limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3; 132 limit->p_cpulimit = RLIM_INFINITY; 133 limit->p_refcnt = 1; 134 spin_init(&limit->p_spin, "plimitinit"); 135 } 136 137 /* 138 * Return a plimit for use by a new forked process given the one 139 * contained in the parent process. 140 */ 141 struct plimit * 142 plimit_fork(struct proc *p1) 143 { 144 struct plimit *olimit = p1->p_limit; 145 struct plimit *nlimit; 146 uint32_t count; 147 148 /* 149 * Try to share the parent's plimit structure. If we cannot, make 150 * a copy. 151 * 152 * NOTE: (count) value is field prior to increment. 153 */ 154 count = atomic_fetchadd_int(&olimit->p_refcnt, 1); 155 cpu_ccfence(); 156 if (count & PLIMITF_EXCLUSIVE) { 157 if ((count & PLIMITF_MASK) == 1 && p1->p_nthreads == 1) { 158 atomic_clear_int(&olimit->p_refcnt, PLIMITF_EXCLUSIVE); 159 } else { 160 nlimit = kmalloc(sizeof(*nlimit), M_PLIMIT, M_WAITOK); 161 plimit_copy(olimit, nlimit); 162 plimit_free(olimit); 163 olimit = nlimit; 164 } 165 } 166 return olimit; 167 } 168 169 /* 170 * This routine is called when a new LWP is created for a process. We 171 * must force exclusivity to ensure that p->p_limit remains stable. 172 * 173 * LWPs share the same process structure so this does not bump refcnt. 174 */ 175 void 176 plimit_lwp_fork(struct proc *p) 177 { 178 struct plimit *olimit = p->p_limit; 179 struct plimit *nlimit; 180 uint32_t count; 181 182 count = olimit->p_refcnt; 183 cpu_ccfence(); 184 if ((count & PLIMITF_EXCLUSIVE) == 0) { 185 if (count != 1) { 186 nlimit = kmalloc(sizeof(*nlimit), M_PLIMIT, M_WAITOK); 187 plimit_copy(olimit, nlimit); 188 p->p_limit = nlimit; 189 plimit_free(olimit); 190 olimit = nlimit; 191 } 192 atomic_set_int(&olimit->p_refcnt, PLIMITF_EXCLUSIVE); 193 } 194 } 195 196 /* 197 * This routine is called to fixup a process's p_limit structure prior 198 * to it being modified. If index >= 0 the specified modification is also 199 * made. 200 * 201 * This routine must make the limit structure exclusive. If we are threaded, 202 * the structure will already be exclusive. A later fork will convert it 203 * back to copy-on-write if possible. 204 * 205 * We can count on p->p_limit being stable since if we had created any 206 * threads it will have already been made exclusive. 207 */ 208 void 209 plimit_modify(struct proc *p, int index, struct rlimit *rlim) 210 { 211 struct plimit *olimit; 212 struct plimit *nlimit; 213 uint32_t count; 214 215 /* 216 * Make exclusive 217 */ 218 olimit = p->p_limit; 219 count = olimit->p_refcnt; 220 cpu_ccfence(); 221 if ((count & PLIMITF_EXCLUSIVE) == 0) { 222 if (count != 1) { 223 nlimit = kmalloc(sizeof(*nlimit), M_PLIMIT, M_WAITOK); 224 plimit_copy(olimit, nlimit); 225 p->p_limit = nlimit; 226 plimit_free(olimit); 227 olimit = nlimit; 228 } 229 atomic_set_int(&olimit->p_refcnt, PLIMITF_EXCLUSIVE); 230 } 231 232 /* 233 * Make modification 234 */ 235 if (index >= 0) { 236 if (p->p_nthreads == 1) { 237 p->p_limit->pl_rlimit[index] = *rlim; 238 } else { 239 spin_lock(&olimit->p_spin); 240 p->p_limit->pl_rlimit[index].rlim_cur = rlim->rlim_cur; 241 p->p_limit->pl_rlimit[index].rlim_max = rlim->rlim_max; 242 spin_unlock(&olimit->p_spin); 243 } 244 } 245 } 246 247 /* 248 * Destroy a process's plimit structure. 249 */ 250 void 251 plimit_free(struct plimit *limit) 252 { 253 uint32_t count; 254 255 count = atomic_fetchadd_int(&limit->p_refcnt, -1); 256 257 if ((count & ~PLIMITF_EXCLUSIVE) == 1) { 258 limit->p_refcnt = -999; 259 kfree(limit, M_PLIMIT); 260 } 261 } 262 263 /* 264 * Modify a resource limit (from system call) 265 */ 266 int 267 kern_setrlimit(u_int which, struct rlimit *limp) 268 { 269 struct proc *p = curproc; 270 struct plimit *limit; 271 struct rlimit *alimp; 272 int error; 273 274 if (which >= RLIM_NLIMITS) 275 return (EINVAL); 276 277 /* 278 * We will be modifying a resource, make a copy if necessary. 279 */ 280 plimit_modify(p, -1, NULL); 281 limit = p->p_limit; 282 alimp = &limit->pl_rlimit[which]; 283 284 /* 285 * Preserve historical bugs by treating negative limits as unsigned. 286 */ 287 if (limp->rlim_cur < 0) 288 limp->rlim_cur = RLIM_INFINITY; 289 if (limp->rlim_max < 0) 290 limp->rlim_max = RLIM_INFINITY; 291 292 spin_lock(&limit->p_spin); 293 if (limp->rlim_cur > alimp->rlim_max || 294 limp->rlim_max > alimp->rlim_max) { 295 spin_unlock(&limit->p_spin); 296 error = priv_check_cred(p->p_ucred, PRIV_PROC_SETRLIMIT, 0); 297 if (error) 298 return (error); 299 } else { 300 spin_unlock(&limit->p_spin); 301 } 302 if (limp->rlim_cur > limp->rlim_max) 303 limp->rlim_cur = limp->rlim_max; 304 305 switch (which) { 306 case RLIMIT_CPU: 307 spin_lock(&limit->p_spin); 308 if (limp->rlim_cur > RLIM_INFINITY / (rlim_t)1000000) 309 limit->p_cpulimit = RLIM_INFINITY; 310 else 311 limit->p_cpulimit = (rlim_t)1000000 * limp->rlim_cur; 312 spin_unlock(&limit->p_spin); 313 break; 314 case RLIMIT_DATA: 315 if (limp->rlim_cur > maxdsiz) 316 limp->rlim_cur = maxdsiz; 317 if (limp->rlim_max > maxdsiz) 318 limp->rlim_max = maxdsiz; 319 break; 320 321 case RLIMIT_STACK: 322 if (limp->rlim_cur > maxssiz) 323 limp->rlim_cur = maxssiz; 324 if (limp->rlim_max > maxssiz) 325 limp->rlim_max = maxssiz; 326 /* 327 * Stack is allocated to the max at exec time with only 328 * "rlim_cur" bytes accessible. If stack limit is going 329 * up make more accessible, if going down make inaccessible. 330 */ 331 spin_lock(&limit->p_spin); 332 if (limp->rlim_cur != alimp->rlim_cur) { 333 vm_offset_t addr; 334 vm_size_t size; 335 vm_prot_t prot; 336 337 if (limp->rlim_cur > alimp->rlim_cur) { 338 prot = VM_PROT_ALL; 339 size = limp->rlim_cur - alimp->rlim_cur; 340 addr = USRSTACK - limp->rlim_cur; 341 } else { 342 prot = VM_PROT_NONE; 343 size = alimp->rlim_cur - limp->rlim_cur; 344 addr = USRSTACK - alimp->rlim_cur; 345 } 346 spin_unlock(&limit->p_spin); 347 addr = trunc_page(addr); 348 size = round_page(size); 349 vm_map_protect(&p->p_vmspace->vm_map, 350 addr, addr+size, prot, FALSE); 351 } else { 352 spin_unlock(&limit->p_spin); 353 } 354 break; 355 356 case RLIMIT_NOFILE: 357 if (limp->rlim_cur > maxfilesperproc) 358 limp->rlim_cur = maxfilesperproc; 359 if (limp->rlim_max > maxfilesperproc) 360 limp->rlim_max = maxfilesperproc; 361 break; 362 363 case RLIMIT_NPROC: 364 if (limp->rlim_cur > maxprocperuid) 365 limp->rlim_cur = maxprocperuid; 366 if (limp->rlim_max > maxprocperuid) 367 limp->rlim_max = maxprocperuid; 368 if (limp->rlim_cur < 1) 369 limp->rlim_cur = 1; 370 if (limp->rlim_max < 1) 371 limp->rlim_max = 1; 372 break; 373 case RLIMIT_POSIXLOCKS: 374 if (limp->rlim_cur > maxposixlocksperuid) 375 limp->rlim_cur = maxposixlocksperuid; 376 if (limp->rlim_max > maxposixlocksperuid) 377 limp->rlim_max = maxposixlocksperuid; 378 break; 379 } 380 spin_lock(&limit->p_spin); 381 *alimp = *limp; 382 spin_unlock(&limit->p_spin); 383 return (0); 384 } 385 386 /* 387 * The rlimit indexed by which is returned in the second argument. 388 */ 389 int 390 kern_getrlimit(u_int which, struct rlimit *limp) 391 { 392 struct proc *p = curproc; 393 struct plimit *limit; 394 395 /* 396 * p is NULL when kern_getrlimit is called from a 397 * kernel thread. In this case as the calling proc 398 * isn't available we just skip the limit check. 399 */ 400 if (p == NULL) 401 return 0; 402 403 if (which >= RLIM_NLIMITS) 404 return (EINVAL); 405 406 limit = readplimits(p); 407 *limp = limit->pl_rlimit[which]; 408 409 return (0); 410 } 411 412 /* 413 * Determine if the cpu limit has been reached and return an operations 414 * code for the caller to perform. 415 */ 416 int 417 plimit_testcpulimit(struct proc *p, u_int64_t ttime) 418 { 419 struct plimit *limit; 420 struct rlimit *rlim; 421 int mode; 422 423 limit = readplimits(p); 424 425 /* 426 * Initial tests without the spinlock. This is the fast path. 427 * Any 32/64 bit glitches will fall through and retest with 428 * the spinlock. 429 */ 430 if (limit->p_cpulimit == RLIM_INFINITY) 431 return(PLIMIT_TESTCPU_OK); 432 if (ttime <= limit->p_cpulimit) 433 return(PLIMIT_TESTCPU_OK); 434 435 if (ttime > limit->p_cpulimit) { 436 rlim = &limit->pl_rlimit[RLIMIT_CPU]; 437 if (ttime / (rlim_t)1000000 >= rlim->rlim_max + 5) 438 mode = PLIMIT_TESTCPU_KILL; 439 else 440 mode = PLIMIT_TESTCPU_XCPU; 441 } else { 442 mode = PLIMIT_TESTCPU_OK; 443 } 444 445 return(mode); 446 } 447 448 /* 449 * Helper routine to copy olimit to nlimit and initialize nlimit for 450 * use. nlimit's reference count will be set to 1 and its exclusive bit 451 * will be cleared. 452 */ 453 static 454 void 455 plimit_copy(struct plimit *olimit, struct plimit *nlimit) 456 { 457 *nlimit = *olimit; 458 459 spin_init(&nlimit->p_spin, "plimitcopy"); 460 nlimit->p_refcnt = 1; 461 } 462 463 /* 464 * This routine returns the value of a resource, downscaled based on 465 * the processes fork depth and chroot depth (up to 50%). This mechanism 466 * is designed to prevent run-aways from blowing up unrelated processes 467 * running under the same UID. 468 * 469 * NOTE: Currently only applicable to RLIMIT_NPROC. We could also limit 470 * file descriptors but we shouldn't have to as these are allocated 471 * dynamically. 472 */ 473 u_int64_t 474 plimit_getadjvalue(int i) 475 { 476 struct proc *p = curproc; 477 struct plimit *limit; 478 uint64_t v; 479 uint32_t depth; 480 481 limit = p->p_limit; 482 v = limit->pl_rlimit[i].rlim_cur; 483 if (i == RLIMIT_NPROC) { 484 /* 485 * 10% per chroot (around 1/3% per fork depth), with a 486 * maximum of 50% downscaling of the resource limit. 487 */ 488 depth = p->p_depth; 489 if (depth > 32 * 5) 490 depth = 32 * 5; 491 v -= v * depth / 320; 492 } 493 return v; 494 } 495