audit_bsm_klib.c revision 178186
1/* 2 * Copyright (c) 1999-2005 Apple Computer, 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 Computer, 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: head/sys/security/audit/audit_bsm_klib.c 178186 2008-04-13 22:06:56Z rwatson $"); 33 34#include <sys/param.h> 35#include <sys/fcntl.h> 36#include <sys/filedesc.h> 37#include <sys/libkern.h> 38#include <sys/malloc.h> 39#include <sys/mount.h> 40#include <sys/proc.h> 41#include <sys/sem.h> 42#include <sys/syscall.h> 43#include <sys/sysctl.h> 44#include <sys/sysent.h> 45#include <sys/vnode.h> 46 47#include <bsm/audit.h> 48#include <bsm/audit_kevents.h> 49#include <security/audit/audit.h> 50#include <security/audit/audit_private.h> 51 52/* 53 * Hash table functions for the audit event number to event class mask 54 * mapping. 55 */ 56#define EVCLASSMAP_HASH_TABLE_SIZE 251 57struct evclass_elem { 58 au_event_t event; 59 au_class_t class; 60 LIST_ENTRY(evclass_elem) entry; 61}; 62struct evclass_list { 63 LIST_HEAD(, evclass_elem) head; 64}; 65 66static MALLOC_DEFINE(M_AUDITEVCLASS, "audit_evclass", "Audit event class"); 67static struct mtx evclass_mtx; 68static struct evclass_list evclass_hash[EVCLASSMAP_HASH_TABLE_SIZE]; 69 70/* 71 * Look up the class for an audit event in the class mapping table. 72 */ 73au_class_t 74au_event_class(au_event_t event) 75{ 76 struct evclass_list *evcl; 77 struct evclass_elem *evc; 78 au_class_t class; 79 80 mtx_lock(&evclass_mtx); 81 evcl = &evclass_hash[event % EVCLASSMAP_HASH_TABLE_SIZE]; 82 class = 0; 83 LIST_FOREACH(evc, &evcl->head, entry) { 84 if (evc->event == event) { 85 class = evc->class; 86 goto out; 87 } 88 } 89out: 90 mtx_unlock(&evclass_mtx); 91 return (class); 92} 93 94/* 95 * Insert a event to class mapping. If the event already exists in the 96 * mapping, then replace the mapping with the new one. 97 * 98 * XXX There is currently no constraints placed on the number of mappings. 99 * May want to either limit to a number, or in terms of memory usage. 100 */ 101void 102au_evclassmap_insert(au_event_t event, au_class_t class) 103{ 104 struct evclass_list *evcl; 105 struct evclass_elem *evc, *evc_new; 106 107 /* 108 * Pessimistically, always allocate storage before acquiring mutex. 109 * Free if there is already a mapping for this event. 110 */ 111 evc_new = malloc(sizeof(*evc), M_AUDITEVCLASS, M_WAITOK); 112 113 mtx_lock(&evclass_mtx); 114 evcl = &evclass_hash[event % EVCLASSMAP_HASH_TABLE_SIZE]; 115 LIST_FOREACH(evc, &evcl->head, entry) { 116 if (evc->event == event) { 117 evc->class = class; 118 mtx_unlock(&evclass_mtx); 119 free(evc_new, M_AUDITEVCLASS); 120 return; 121 } 122 } 123 evc = evc_new; 124 evc->event = event; 125 evc->class = class; 126 LIST_INSERT_HEAD(&evcl->head, evc, entry); 127 mtx_unlock(&evclass_mtx); 128} 129 130void 131au_evclassmap_init(void) 132{ 133 int i; 134 135 mtx_init(&evclass_mtx, "evclass_mtx", NULL, MTX_DEF); 136 for (i = 0; i < EVCLASSMAP_HASH_TABLE_SIZE; i++) 137 LIST_INIT(&evclass_hash[i].head); 138 139 /* 140 * Set up the initial event to class mapping for system calls. 141 * 142 * XXXRW: Really, this should walk all possible audit events, not all 143 * native ABI system calls, as there may be audit events reachable 144 * only through non-native system calls. It also seems a shame to 145 * frob the mutex this early. 146 */ 147 for (i = 0; i < SYS_MAXSYSCALL; i++) { 148 if (sysent[i].sy_auevent != AUE_NULL) 149 au_evclassmap_insert(sysent[i].sy_auevent, 0); 150 } 151} 152 153/* 154 * Check whether an event is aditable by comparing the mask of classes this 155 * event is part of against the given mask. 156 */ 157int 158au_preselect(au_event_t event, au_class_t class, au_mask_t *mask_p, int sorf) 159{ 160 au_class_t effmask = 0; 161 162 if (mask_p == NULL) 163 return (-1); 164 165 /* 166 * Perform the actual check of the masks against the event. 167 */ 168 if (sorf & AU_PRS_SUCCESS) 169 effmask |= (mask_p->am_success & class); 170 171 if (sorf & AU_PRS_FAILURE) 172 effmask |= (mask_p->am_failure & class); 173 174 if (effmask) 175 return (1); 176 else 177 return (0); 178} 179 180/* 181 * Convert sysctl names and present arguments to events. 182 */ 183au_event_t 184audit_ctlname_to_sysctlevent(int name[], uint64_t valid_arg) 185{ 186 187 /* can't parse it - so return the worst case */ 188 if ((valid_arg & (ARG_CTLNAME | ARG_LEN)) != (ARG_CTLNAME | ARG_LEN)) 189 return (AUE_SYSCTL); 190 191 switch (name[0]) { 192 /* non-admin "lookups" treat them special */ 193 case KERN_OSTYPE: 194 case KERN_OSRELEASE: 195 case KERN_OSREV: 196 case KERN_VERSION: 197 case KERN_ARGMAX: 198 case KERN_CLOCKRATE: 199 case KERN_BOOTTIME: 200 case KERN_POSIX1: 201 case KERN_NGROUPS: 202 case KERN_JOB_CONTROL: 203 case KERN_SAVED_IDS: 204 case KERN_OSRELDATE: 205 case KERN_DUMMY: 206 return (AUE_SYSCTL_NONADMIN); 207 208 /* only treat the changeable controls as admin */ 209 case KERN_MAXVNODES: 210 case KERN_MAXPROC: 211 case KERN_MAXFILES: 212 case KERN_MAXPROCPERUID: 213 case KERN_MAXFILESPERPROC: 214 case KERN_HOSTID: 215 case KERN_SECURELVL: 216 case KERN_HOSTNAME: 217 case KERN_VNODE: 218 case KERN_PROC: 219 case KERN_FILE: 220 case KERN_PROF: 221 case KERN_NISDOMAINNAME: 222 case KERN_UPDATEINTERVAL: 223 case KERN_NTP_PLL: 224 case KERN_BOOTFILE: 225 case KERN_DUMPDEV: 226 case KERN_IPC: 227 case KERN_PS_STRINGS: 228 case KERN_USRSTACK: 229 case KERN_LOGSIGEXIT: 230 case KERN_IOV_MAX: 231 case KERN_MAXID: 232 return ((valid_arg & ARG_VALUE) ? 233 AUE_SYSCTL : AUE_SYSCTL_NONADMIN); 234 235 default: 236 return (AUE_SYSCTL); 237 } 238 /* NOTREACHED */ 239} 240 241/* 242 * Convert an open flags specifier into a specific type of open event for 243 * auditing purposes. 244 */ 245au_event_t 246audit_flags_and_error_to_openevent(int oflags, int error) 247{ 248 au_event_t aevent; 249 250 /* 251 * Need to check only those flags we care about. 252 */ 253 oflags = oflags & (O_RDONLY | O_CREAT | O_TRUNC | O_RDWR | O_WRONLY); 254 255 /* 256 * These checks determine what flags are on with the condition that 257 * ONLY that combination is on, and no other flags are on. 258 */ 259 switch (oflags) { 260 case O_RDONLY: 261 aevent = AUE_OPEN_R; 262 break; 263 264 case (O_RDONLY | O_CREAT): 265 aevent = AUE_OPEN_RC; 266 break; 267 268 case (O_RDONLY | O_CREAT | O_TRUNC): 269 aevent = AUE_OPEN_RTC; 270 break; 271 272 case (O_RDONLY | O_TRUNC): 273 aevent = AUE_OPEN_RT; 274 break; 275 276 case O_RDWR: 277 aevent = AUE_OPEN_RW; 278 break; 279 280 case (O_RDWR | O_CREAT): 281 aevent = AUE_OPEN_RWC; 282 break; 283 284 case (O_RDWR | O_CREAT | O_TRUNC): 285 aevent = AUE_OPEN_RWTC; 286 break; 287 288 case (O_RDWR | O_TRUNC): 289 aevent = AUE_OPEN_RWT; 290 break; 291 292 case O_WRONLY: 293 aevent = AUE_OPEN_W; 294 break; 295 296 case (O_WRONLY | O_CREAT): 297 aevent = AUE_OPEN_WC; 298 break; 299 300 case (O_WRONLY | O_CREAT | O_TRUNC): 301 aevent = AUE_OPEN_WTC; 302 break; 303 304 case (O_WRONLY | O_TRUNC): 305 aevent = AUE_OPEN_WT; 306 break; 307 308 default: 309 aevent = AUE_OPEN; 310 break; 311 } 312 313#if 0 314 /* 315 * Convert chatty errors to better matching events. Failures to 316 * find a file are really just attribute events -- so recast them as 317 * such. 318 * 319 * XXXAUDIT: Solaris defines that AUE_OPEN will never be returned, it 320 * is just a placeholder. However, in Darwin we return that in 321 * preference to other events. For now, comment this out as we don't 322 * have a BSM conversion routine for AUE_OPEN. 323 */ 324 switch (aevent) { 325 case AUE_OPEN_R: 326 case AUE_OPEN_RT: 327 case AUE_OPEN_RW: 328 case AUE_OPEN_RWT: 329 case AUE_OPEN_W: 330 case AUE_OPEN_WT: 331 if (error == ENOENT) 332 aevent = AUE_OPEN; 333 } 334#endif 335 return (aevent); 336} 337 338/* 339 * Convert a MSGCTL command to a specific event. 340 */ 341int 342audit_msgctl_to_event(int cmd) 343{ 344 345 switch (cmd) { 346 case IPC_RMID: 347 return (AUE_MSGCTL_RMID); 348 349 case IPC_SET: 350 return (AUE_MSGCTL_SET); 351 352 case IPC_STAT: 353 return (AUE_MSGCTL_STAT); 354 355 default: 356 /* We will audit a bad command. */ 357 return (AUE_MSGCTL); 358 } 359} 360 361/* 362 * Convert a SEMCTL command to a specific event. 363 */ 364int 365audit_semctl_to_event(int cmd) 366{ 367 368 switch (cmd) { 369 case GETALL: 370 return (AUE_SEMCTL_GETALL); 371 372 case GETNCNT: 373 return (AUE_SEMCTL_GETNCNT); 374 375 case GETPID: 376 return (AUE_SEMCTL_GETPID); 377 378 case GETVAL: 379 return (AUE_SEMCTL_GETVAL); 380 381 case GETZCNT: 382 return (AUE_SEMCTL_GETZCNT); 383 384 case IPC_RMID: 385 return (AUE_SEMCTL_RMID); 386 387 case IPC_SET: 388 return (AUE_SEMCTL_SET); 389 390 case SETALL: 391 return (AUE_SEMCTL_SETALL); 392 393 case SETVAL: 394 return (AUE_SEMCTL_SETVAL); 395 396 case IPC_STAT: 397 return (AUE_SEMCTL_STAT); 398 399 default: 400 /* We will audit a bad command */ 401 return (AUE_SEMCTL); 402 } 403} 404 405/* 406 * Convert a command for the auditon() system call to a audit event. 407 */ 408int 409auditon_command_event(int cmd) 410{ 411 412 switch(cmd) { 413 case A_GETPOLICY: 414 return (AUE_AUDITON_GPOLICY); 415 416 case A_SETPOLICY: 417 return (AUE_AUDITON_SPOLICY); 418 419 case A_GETKMASK: 420 return (AUE_AUDITON_GETKMASK); 421 422 case A_SETKMASK: 423 return (AUE_AUDITON_SETKMASK); 424 425 case A_GETQCTRL: 426 return (AUE_AUDITON_GQCTRL); 427 428 case A_SETQCTRL: 429 return (AUE_AUDITON_SQCTRL); 430 431 case A_GETCWD: 432 return (AUE_AUDITON_GETCWD); 433 434 case A_GETCAR: 435 return (AUE_AUDITON_GETCAR); 436 437 case A_GETSTAT: 438 return (AUE_AUDITON_GETSTAT); 439 440 case A_SETSTAT: 441 return (AUE_AUDITON_SETSTAT); 442 443 case A_SETUMASK: 444 return (AUE_AUDITON_SETUMASK); 445 446 case A_SETSMASK: 447 return (AUE_AUDITON_SETSMASK); 448 449 case A_GETCOND: 450 return (AUE_AUDITON_GETCOND); 451 452 case A_SETCOND: 453 return (AUE_AUDITON_SETCOND); 454 455 case A_GETCLASS: 456 return (AUE_AUDITON_GETCLASS); 457 458 case A_SETCLASS: 459 return (AUE_AUDITON_SETCLASS); 460 461 case A_GETPINFO: 462 case A_SETPMASK: 463 case A_SETFSIZE: 464 case A_GETFSIZE: 465 case A_GETPINFO_ADDR: 466 case A_GETKAUDIT: 467 case A_SETKAUDIT: 468 default: 469 return (AUE_AUDITON); /* No special record */ 470 } 471} 472 473/* 474 * Create a canonical path from given path by prefixing either the root 475 * directory, or the current working directory. If the process working 476 * directory is NULL, we could use 'rootvnode' to obtain the root directory, 477 * but this results in a volfs name written to the audit log. So we will 478 * leave the filename starting with '/' in the audit log in this case. 479 * 480 * XXXRW: Since we combine two paths here, ideally a buffer of size 481 * MAXPATHLEN * 2 would be passed in. 482 */ 483void 484audit_canon_path(struct thread *td, char *path, char *cpath) 485{ 486 char *bufp; 487 char *retbuf, *freebuf; 488 struct vnode *vnp; 489 struct filedesc *fdp; 490 int cisr, error, vfslocked; 491 492 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 493 "audit_canon_path() at %s:%d", __FILE__, __LINE__); 494 495 fdp = td->td_proc->p_fd; 496 bufp = path; 497 cisr = 0; 498 FILEDESC_SLOCK(fdp); 499 if (*(path) == '/') { 500 while (*(bufp) == '/') 501 bufp++; /* Skip leading '/'s. */ 502 /* 503 * If no process root, or it is the same as the system root, 504 * audit the path as passed in with a single '/'. 505 */ 506 if ((fdp->fd_rdir == NULL) || 507 (fdp->fd_rdir == rootvnode)) { 508 vnp = NULL; 509 bufp--; /* Restore one '/'. */ 510 } else { 511 vnp = fdp->fd_rdir; /* Use process root. */ 512 vref(vnp); 513 } 514 } else { 515 vnp = fdp->fd_cdir; /* Prepend the current dir. */ 516 cisr = (fdp->fd_rdir == fdp->fd_cdir); 517 vref(vnp); 518 bufp = path; 519 } 520 FILEDESC_SUNLOCK(fdp); 521 if (vnp != NULL) { 522 /* 523 * XXX: vn_fullpath() on FreeBSD is "less reliable" than 524 * vn_getpath() on Darwin, so this will need more attention 525 * in the future. Also, the question and string bounding 526 * here seems a bit questionable and will also require 527 * attention. 528 */ 529 vfslocked = VFS_LOCK_GIANT(vnp->v_mount); 530 vn_lock(vnp, LK_EXCLUSIVE | LK_RETRY); 531 error = vn_fullpath(td, vnp, &retbuf, &freebuf); 532 if (error == 0) { 533 /* Copy and free buffer allocated by vn_fullpath(). 534 * If the current working directory was the same as 535 * the root directory, and the path was a relative 536 * pathname, do not separate the two components with 537 * the '/' character. 538 */ 539 snprintf(cpath, MAXPATHLEN, "%s%s%s", retbuf, 540 cisr ? "" : "/", bufp); 541 free(freebuf, M_TEMP); 542 } else 543 cpath[0] = '\0'; 544 vput(vnp); 545 VFS_UNLOCK_GIANT(vfslocked); 546 } else 547 strlcpy(cpath, bufp, MAXPATHLEN); 548} 549