1 /* 2 * Copyright (c) 1999-2009 Apple Inc. 3 * Copyright (c) 2005 Robert N. M. Watson 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of Apple Inc. ("Apple") nor the names of 15 * its contributors may be used to endorse or promote products derived 16 * from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR 22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 26 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 27 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/param.h> 35 #include <sys/capsicum.h> 36 #include <sys/fcntl.h> 37 #include <sys/filedesc.h> 38 #include <sys/libkern.h> 39 #include <sys/malloc.h> 40 #include <sys/mount.h> 41 #include <sys/proc.h> 42 #include <sys/rwlock.h> 43 #include <sys/sem.h> 44 #include <sys/sbuf.h> 45 #include <sys/syscall.h> 46 #include <sys/sysctl.h> 47 #include <sys/sysent.h> 48 #include <sys/vnode.h> 49 50 #include <bsm/audit.h> 51 #include <bsm/audit_kevents.h> 52 #include <security/audit/audit.h> 53 #include <security/audit/audit_private.h> 54 55 /* 56 * Hash table functions for the audit event number to event class mask 57 * mapping. 58 */ 59 #define EVCLASSMAP_HASH_TABLE_SIZE 251 60 struct evclass_elem { 61 au_event_t event; 62 au_class_t class; 63 LIST_ENTRY(evclass_elem) entry; 64 }; 65 struct evclass_list { 66 LIST_HEAD(, evclass_elem) head; 67 }; 68 69 static MALLOC_DEFINE(M_AUDITEVCLASS, "audit_evclass", "Audit event class"); 70 static struct rwlock evclass_lock; 71 static struct evclass_list evclass_hash[EVCLASSMAP_HASH_TABLE_SIZE]; 72 73 #define EVCLASS_LOCK_INIT() rw_init(&evclass_lock, "evclass_lock") 74 #define EVCLASS_RLOCK() rw_rlock(&evclass_lock) 75 #define EVCLASS_RUNLOCK() rw_runlock(&evclass_lock) 76 #define EVCLASS_WLOCK() rw_wlock(&evclass_lock) 77 #define EVCLASS_WUNLOCK() rw_wunlock(&evclass_lock) 78 79 struct aue_open_event { 80 int aoe_flags; 81 au_event_t aoe_event; 82 }; 83 84 static const struct aue_open_event aue_open[] = { 85 { O_RDONLY, AUE_OPEN_R }, 86 { (O_RDONLY | O_CREAT), AUE_OPEN_RC }, 87 { (O_RDONLY | O_CREAT | O_TRUNC), AUE_OPEN_RTC }, 88 { (O_RDONLY | O_TRUNC), AUE_OPEN_RT }, 89 { O_RDWR, AUE_OPEN_RW }, 90 { (O_RDWR | O_CREAT), AUE_OPEN_RWC }, 91 { (O_RDWR | O_CREAT | O_TRUNC), AUE_OPEN_RWTC }, 92 { (O_RDWR | O_TRUNC), AUE_OPEN_RWT }, 93 { O_WRONLY, AUE_OPEN_W }, 94 { (O_WRONLY | O_CREAT), AUE_OPEN_WC }, 95 { (O_WRONLY | O_CREAT | O_TRUNC), AUE_OPEN_WTC }, 96 { (O_WRONLY | O_TRUNC), AUE_OPEN_WT }, 97 }; 98 99 static const struct aue_open_event aue_openat[] = { 100 { O_RDONLY, AUE_OPENAT_R }, 101 { (O_RDONLY | O_CREAT), AUE_OPENAT_RC }, 102 { (O_RDONLY | O_CREAT | O_TRUNC), AUE_OPENAT_RTC }, 103 { (O_RDONLY | O_TRUNC), AUE_OPENAT_RT }, 104 { O_RDWR, AUE_OPENAT_RW }, 105 { (O_RDWR | O_CREAT), AUE_OPENAT_RWC }, 106 { (O_RDWR | O_CREAT | O_TRUNC), AUE_OPENAT_RWTC }, 107 { (O_RDWR | O_TRUNC), AUE_OPENAT_RWT }, 108 { O_WRONLY, AUE_OPENAT_W }, 109 { (O_WRONLY | O_CREAT), AUE_OPENAT_WC }, 110 { (O_WRONLY | O_CREAT | O_TRUNC), AUE_OPENAT_WTC }, 111 { (O_WRONLY | O_TRUNC), AUE_OPENAT_WT }, 112 }; 113 114 /* 115 * Look up the class for an audit event in the class mapping table. 116 */ 117 au_class_t 118 au_event_class(au_event_t event) 119 { 120 struct evclass_list *evcl; 121 struct evclass_elem *evc; 122 au_class_t class; 123 124 EVCLASS_RLOCK(); 125 evcl = &evclass_hash[event % EVCLASSMAP_HASH_TABLE_SIZE]; 126 class = 0; 127 LIST_FOREACH(evc, &evcl->head, entry) { 128 if (evc->event == event) { 129 class = evc->class; 130 goto out; 131 } 132 } 133 out: 134 EVCLASS_RUNLOCK(); 135 return (class); 136 } 137 138 /* 139 * Insert a event to class mapping. If the event already exists in the 140 * mapping, then replace the mapping with the new one. 141 * 142 * XXX There is currently no constraints placed on the number of mappings. 143 * May want to either limit to a number, or in terms of memory usage. 144 */ 145 void 146 au_evclassmap_insert(au_event_t event, au_class_t class) 147 { 148 struct evclass_list *evcl; 149 struct evclass_elem *evc, *evc_new; 150 151 /* 152 * Pessimistically, always allocate storage before acquiring mutex. 153 * Free if there is already a mapping for this event. 154 */ 155 evc_new = malloc(sizeof(*evc), M_AUDITEVCLASS, M_WAITOK); 156 157 EVCLASS_WLOCK(); 158 evcl = &evclass_hash[event % EVCLASSMAP_HASH_TABLE_SIZE]; 159 LIST_FOREACH(evc, &evcl->head, entry) { 160 if (evc->event == event) { 161 evc->class = class; 162 EVCLASS_WUNLOCK(); 163 free(evc_new, M_AUDITEVCLASS); 164 return; 165 } 166 } 167 evc = evc_new; 168 evc->event = event; 169 evc->class = class; 170 LIST_INSERT_HEAD(&evcl->head, evc, entry); 171 EVCLASS_WUNLOCK(); 172 } 173 174 void 175 au_evclassmap_init(void) 176 { 177 int i; 178 179 EVCLASS_LOCK_INIT(); 180 for (i = 0; i < EVCLASSMAP_HASH_TABLE_SIZE; i++) 181 LIST_INIT(&evclass_hash[i].head); 182 183 /* 184 * Set up the initial event to class mapping for system calls. 185 * 186 * XXXRW: Really, this should walk all possible audit events, not all 187 * native ABI system calls, as there may be audit events reachable 188 * only through non-native system calls. It also seems a shame to 189 * frob the mutex this early. 190 */ 191 for (i = 0; i < SYS_MAXSYSCALL; i++) { 192 if (sysent[i].sy_auevent != AUE_NULL) 193 au_evclassmap_insert(sysent[i].sy_auevent, 0); 194 } 195 } 196 197 /* 198 * Check whether an event is aditable by comparing the mask of classes this 199 * event is part of against the given mask. 200 */ 201 int 202 au_preselect(au_event_t event, au_class_t class, au_mask_t *mask_p, int sorf) 203 { 204 au_class_t effmask = 0; 205 206 if (mask_p == NULL) 207 return (-1); 208 209 /* 210 * Perform the actual check of the masks against the event. 211 */ 212 if (sorf & AU_PRS_SUCCESS) 213 effmask |= (mask_p->am_success & class); 214 215 if (sorf & AU_PRS_FAILURE) 216 effmask |= (mask_p->am_failure & class); 217 218 if (effmask) 219 return (1); 220 else 221 return (0); 222 } 223 224 /* 225 * Convert sysctl names and present arguments to events. 226 */ 227 au_event_t 228 audit_ctlname_to_sysctlevent(int name[], uint64_t valid_arg) 229 { 230 231 /* can't parse it - so return the worst case */ 232 if ((valid_arg & (ARG_CTLNAME | ARG_LEN)) != (ARG_CTLNAME | ARG_LEN)) 233 return (AUE_SYSCTL); 234 235 switch (name[0]) { 236 /* non-admin "lookups" treat them special */ 237 case KERN_OSTYPE: 238 case KERN_OSRELEASE: 239 case KERN_OSREV: 240 case KERN_VERSION: 241 case KERN_ARGMAX: 242 case KERN_CLOCKRATE: 243 case KERN_BOOTTIME: 244 case KERN_POSIX1: 245 case KERN_NGROUPS: 246 case KERN_JOB_CONTROL: 247 case KERN_SAVED_IDS: 248 case KERN_OSRELDATE: 249 case KERN_DUMMY: 250 return (AUE_SYSCTL_NONADMIN); 251 252 /* only treat the changeable controls as admin */ 253 case KERN_MAXVNODES: 254 case KERN_MAXPROC: 255 case KERN_MAXFILES: 256 case KERN_MAXPROCPERUID: 257 case KERN_MAXFILESPERPROC: 258 case KERN_HOSTID: 259 case KERN_SECURELVL: 260 case KERN_HOSTNAME: 261 case KERN_VNODE: 262 case KERN_PROC: 263 case KERN_FILE: 264 case KERN_PROF: 265 case KERN_NISDOMAINNAME: 266 case KERN_UPDATEINTERVAL: 267 case KERN_NTP_PLL: 268 case KERN_BOOTFILE: 269 case KERN_DUMPDEV: 270 case KERN_IPC: 271 case KERN_PS_STRINGS: 272 case KERN_USRSTACK: 273 case KERN_LOGSIGEXIT: 274 case KERN_IOV_MAX: 275 return ((valid_arg & ARG_VALUE) ? 276 AUE_SYSCTL : AUE_SYSCTL_NONADMIN); 277 278 default: 279 return (AUE_SYSCTL); 280 } 281 /* NOTREACHED */ 282 } 283 284 /* 285 * Convert an open flags specifier into a specific type of open event for 286 * auditing purposes. 287 */ 288 au_event_t 289 audit_flags_and_error_to_openevent(int oflags, int error) 290 { 291 int i; 292 293 /* 294 * Need to check only those flags we care about. 295 */ 296 oflags = oflags & (O_RDONLY | O_CREAT | O_TRUNC | O_RDWR | O_WRONLY); 297 for (i = 0; i < nitems(aue_open); i++) { 298 if (aue_open[i].aoe_flags == oflags) 299 return (aue_open[i].aoe_event); 300 } 301 return (AUE_OPEN); 302 } 303 304 au_event_t 305 audit_flags_and_error_to_openatevent(int oflags, int error) 306 { 307 int i; 308 309 /* 310 * Need to check only those flags we care about. 311 */ 312 oflags = oflags & (O_RDONLY | O_CREAT | O_TRUNC | O_RDWR | O_WRONLY); 313 for (i = 0; i < nitems(aue_openat); i++) { 314 if (aue_openat[i].aoe_flags == oflags) 315 return (aue_openat[i].aoe_event); 316 } 317 return (AUE_OPENAT); 318 } 319 320 /* 321 * Convert a MSGCTL command to a specific event. 322 */ 323 au_event_t 324 audit_msgctl_to_event(int cmd) 325 { 326 327 switch (cmd) { 328 case IPC_RMID: 329 return (AUE_MSGCTL_RMID); 330 331 case IPC_SET: 332 return (AUE_MSGCTL_SET); 333 334 case IPC_STAT: 335 return (AUE_MSGCTL_STAT); 336 337 default: 338 /* We will audit a bad command. */ 339 return (AUE_MSGCTL); 340 } 341 } 342 343 /* 344 * Convert a SEMCTL command to a specific event. 345 */ 346 au_event_t 347 audit_semctl_to_event(int cmd) 348 { 349 350 switch (cmd) { 351 case GETALL: 352 return (AUE_SEMCTL_GETALL); 353 354 case GETNCNT: 355 return (AUE_SEMCTL_GETNCNT); 356 357 case GETPID: 358 return (AUE_SEMCTL_GETPID); 359 360 case GETVAL: 361 return (AUE_SEMCTL_GETVAL); 362 363 case GETZCNT: 364 return (AUE_SEMCTL_GETZCNT); 365 366 case IPC_RMID: 367 return (AUE_SEMCTL_RMID); 368 369 case IPC_SET: 370 return (AUE_SEMCTL_SET); 371 372 case SETALL: 373 return (AUE_SEMCTL_SETALL); 374 375 case SETVAL: 376 return (AUE_SEMCTL_SETVAL); 377 378 case IPC_STAT: 379 return (AUE_SEMCTL_STAT); 380 381 default: 382 /* We will audit a bad command. */ 383 return (AUE_SEMCTL); 384 } 385 } 386 387 /* 388 * Convert a command for the auditon() system call to a audit event. 389 */ 390 au_event_t 391 auditon_command_event(int cmd) 392 { 393 394 switch(cmd) { 395 case A_GETPOLICY: 396 return (AUE_AUDITON_GPOLICY); 397 398 case A_SETPOLICY: 399 return (AUE_AUDITON_SPOLICY); 400 401 case A_GETKMASK: 402 return (AUE_AUDITON_GETKMASK); 403 404 case A_SETKMASK: 405 return (AUE_AUDITON_SETKMASK); 406 407 case A_GETQCTRL: 408 return (AUE_AUDITON_GQCTRL); 409 410 case A_SETQCTRL: 411 return (AUE_AUDITON_SQCTRL); 412 413 case A_GETCWD: 414 return (AUE_AUDITON_GETCWD); 415 416 case A_GETCAR: 417 return (AUE_AUDITON_GETCAR); 418 419 case A_GETSTAT: 420 return (AUE_AUDITON_GETSTAT); 421 422 case A_SETSTAT: 423 return (AUE_AUDITON_SETSTAT); 424 425 case A_SETUMASK: 426 return (AUE_AUDITON_SETUMASK); 427 428 case A_SETSMASK: 429 return (AUE_AUDITON_SETSMASK); 430 431 case A_GETCOND: 432 return (AUE_AUDITON_GETCOND); 433 434 case A_SETCOND: 435 return (AUE_AUDITON_SETCOND); 436 437 case A_GETCLASS: 438 return (AUE_AUDITON_GETCLASS); 439 440 case A_SETCLASS: 441 return (AUE_AUDITON_SETCLASS); 442 443 case A_GETPINFO: 444 case A_SETPMASK: 445 case A_SETFSIZE: 446 case A_GETFSIZE: 447 case A_GETPINFO_ADDR: 448 case A_GETKAUDIT: 449 case A_SETKAUDIT: 450 default: 451 return (AUE_AUDITON); /* No special record */ 452 } 453 } 454 455 /* 456 * Create a canonical path from given path by prefixing either the root 457 * directory, or the current working directory. If the process working 458 * directory is NULL, we could use 'rootvnode' to obtain the root directory, 459 * but this results in a volfs name written to the audit log. So we will 460 * leave the filename starting with '/' in the audit log in this case. 461 */ 462 void 463 audit_canon_path(struct thread *td, int dirfd, char *path, char *cpath) 464 { 465 struct vnode *cvnp, *rvnp; 466 char *rbuf, *fbuf, *copy; 467 struct filedesc *fdp; 468 struct sbuf sbf; 469 cap_rights_t rights; 470 int error, needslash; 471 472 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "%s: at %s:%d", 473 __func__, __FILE__, __LINE__); 474 475 copy = path; 476 rvnp = cvnp = NULL; 477 fdp = td->td_proc->p_fd; 478 FILEDESC_SLOCK(fdp); 479 /* 480 * Make sure that we handle the chroot(2) case. If there is an 481 * alternate root directory, prepend it to the audited pathname. 482 */ 483 if (fdp->fd_rdir != NULL && fdp->fd_rdir != rootvnode) { 484 rvnp = fdp->fd_rdir; 485 vhold(rvnp); 486 } 487 /* 488 * If the supplied path is relative, make sure we capture the current 489 * working directory so we can prepend it to the supplied relative 490 * path. 491 */ 492 if (*path != '/') { 493 if (dirfd == AT_FDCWD) { 494 cvnp = fdp->fd_cdir; 495 vhold(cvnp); 496 } else { 497 /* XXX: fgetvp() that vhold()s vnode instead of vref()ing it would be better */ 498 error = fgetvp(td, dirfd, cap_rights_init(&rights), &cvnp); 499 if (error) { 500 FILEDESC_SUNLOCK(fdp); 501 cpath[0] = '\0'; 502 if (rvnp != NULL) 503 vdrop(rvnp); 504 return; 505 } 506 vhold(cvnp); 507 vrele(cvnp); 508 } 509 needslash = (fdp->fd_rdir != cvnp); 510 } else { 511 needslash = 1; 512 } 513 FILEDESC_SUNLOCK(fdp); 514 /* 515 * NB: We require that the supplied array be at least MAXPATHLEN bytes 516 * long. If this is not the case, then we can run into serious trouble. 517 */ 518 (void) sbuf_new(&sbf, cpath, MAXPATHLEN, SBUF_FIXEDLEN); 519 /* 520 * Strip leading forward slashes. 521 */ 522 while (*copy == '/') 523 copy++; 524 /* 525 * Make sure we handle chroot(2) and prepend the global path to these 526 * environments. 527 * 528 * NB: vn_fullpath(9) on FreeBSD is less reliable than vn_getpath(9) 529 * on Darwin. As a result, this may need some additional attention 530 * in the future. 531 */ 532 if (rvnp != NULL) { 533 error = vn_fullpath_global(td, rvnp, &rbuf, &fbuf); 534 vdrop(rvnp); 535 if (error) { 536 cpath[0] = '\0'; 537 if (cvnp != NULL) 538 vdrop(cvnp); 539 return; 540 } 541 (void) sbuf_cat(&sbf, rbuf); 542 free(fbuf, M_TEMP); 543 } 544 if (cvnp != NULL) { 545 error = vn_fullpath(td, cvnp, &rbuf, &fbuf); 546 vdrop(cvnp); 547 if (error) { 548 cpath[0] = '\0'; 549 return; 550 } 551 (void) sbuf_cat(&sbf, rbuf); 552 free(fbuf, M_TEMP); 553 } 554 if (needslash) 555 (void) sbuf_putc(&sbf, '/'); 556 /* 557 * Now that we have processed any alternate root and relative path 558 * names, add the supplied pathname. 559 */ 560 (void) sbuf_cat(&sbf, copy); 561 /* 562 * One or more of the previous sbuf operations could have resulted in 563 * the supplied buffer being overflowed. Check to see if this is the 564 * case. 565 */ 566 if (sbuf_error(&sbf) != 0) { 567 cpath[0] = '\0'; 568 return; 569 } 570 sbuf_finish(&sbf); 571 } 572