1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1999-2005 Apple Inc. 5 * Copyright (c) 2006-2007, 2016-2018 Robert N. M. Watson 6 * All rights reserved. 7 * 8 * Portions of this software were developed by BAE Systems, the University of 9 * Cambridge Computer Laboratory, and Memorial University under DARPA/AFRL 10 * contract FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent 11 * Computing (TC) research program. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of Apple Inc. ("Apple") nor the names of 22 * its contributors may be used to endorse or promote products derived 23 * from this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR 29 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 33 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 34 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include <sys/param.h> 42 #include <sys/condvar.h> 43 #include <sys/conf.h> 44 #include <sys/eventhandler.h> 45 #include <sys/file.h> 46 #include <sys/filedesc.h> 47 #include <sys/fcntl.h> 48 #include <sys/ipc.h> 49 #include <sys/jail.h> 50 #include <sys/kernel.h> 51 #include <sys/kthread.h> 52 #include <sys/malloc.h> 53 #include <sys/mount.h> 54 #include <sys/namei.h> 55 #include <sys/priv.h> 56 #include <sys/proc.h> 57 #include <sys/queue.h> 58 #include <sys/socket.h> 59 #include <sys/socketvar.h> 60 #include <sys/protosw.h> 61 #include <sys/domain.h> 62 #include <sys/sysctl.h> 63 #include <sys/sysproto.h> 64 #include <sys/sysent.h> 65 #include <sys/systm.h> 66 #include <sys/ucred.h> 67 #include <sys/uio.h> 68 #include <sys/un.h> 69 #include <sys/unistd.h> 70 #include <sys/vnode.h> 71 72 #include <bsm/audit.h> 73 #include <bsm/audit_internal.h> 74 #include <bsm/audit_kevents.h> 75 76 #include <netinet/in.h> 77 #include <netinet/in_pcb.h> 78 79 #include <security/audit/audit.h> 80 #include <security/audit/audit_private.h> 81 82 #include <vm/uma.h> 83 84 FEATURE(audit, "BSM audit support"); 85 86 static uma_zone_t audit_record_zone; 87 static MALLOC_DEFINE(M_AUDITCRED, "audit_cred", "Audit cred storage"); 88 MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage"); 89 MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage"); 90 MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage"); 91 MALLOC_DEFINE(M_AUDITGIDSET, "audit_gidset", "Audit GID set storage"); 92 93 static SYSCTL_NODE(_security, OID_AUTO, audit, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 94 "TrustedBSD audit controls"); 95 96 /* 97 * Audit control settings that are set/read by system calls and are hence 98 * non-static. 99 * 100 * Define the audit control flags. 101 */ 102 int audit_trail_enabled; 103 int audit_trail_suspended; 104 #ifdef KDTRACE_HOOKS 105 u_int audit_dtrace_enabled; 106 #endif 107 bool __read_frequently audit_syscalls_enabled; 108 109 /* 110 * Flags controlling behavior in low storage situations. Should we panic if 111 * a write fails? Should we fail stop if we're out of disk space? 112 */ 113 int audit_panic_on_write_fail; 114 int audit_fail_stop; 115 int audit_argv; 116 int audit_arge; 117 118 /* 119 * Are we currently "failing stop" due to out of disk space? 120 */ 121 int audit_in_failure; 122 123 /* 124 * Global audit statistics. 125 */ 126 struct audit_fstat audit_fstat; 127 128 /* 129 * Preselection mask for non-attributable events. 130 */ 131 struct au_mask audit_nae_mask; 132 133 /* 134 * Mutex to protect global variables shared between various threads and 135 * processes. 136 */ 137 struct mtx audit_mtx; 138 139 /* 140 * Queue of audit records ready for delivery to disk. We insert new records 141 * at the tail, and remove records from the head. Also, a count of the 142 * number of records used for checking queue depth. In addition, a counter 143 * of records that we have allocated but are not yet in the queue, which is 144 * needed to estimate the total size of the combined set of records 145 * outstanding in the system. 146 */ 147 struct kaudit_queue audit_q; 148 int audit_q_len; 149 int audit_pre_q_len; 150 151 /* 152 * Audit queue control settings (minimum free, low/high water marks, etc.) 153 */ 154 struct au_qctrl audit_qctrl; 155 156 /* 157 * Condition variable to signal to the worker that it has work to do: either 158 * new records are in the queue, or a log replacement is taking place. 159 */ 160 struct cv audit_worker_cv; 161 162 /* 163 * Condition variable to flag when crossing the low watermark, meaning that 164 * threads blocked due to hitting the high watermark can wake up and continue 165 * to commit records. 166 */ 167 struct cv audit_watermark_cv; 168 169 /* 170 * Condition variable for auditing threads wait on when in fail-stop mode. 171 * Threads wait on this CV forever (and ever), never seeing the light of day 172 * again. 173 */ 174 static struct cv audit_fail_cv; 175 176 /* 177 * Optional DTrace audit provider support: function pointers for preselection 178 * and commit events. 179 */ 180 #ifdef KDTRACE_HOOKS 181 void *(*dtaudit_hook_preselect)(au_id_t auid, au_event_t event, 182 au_class_t class); 183 int (*dtaudit_hook_commit)(struct kaudit_record *kar, au_id_t auid, 184 au_event_t event, au_class_t class, int sorf); 185 void (*dtaudit_hook_bsm)(struct kaudit_record *kar, au_id_t auid, 186 au_event_t event, au_class_t class, int sorf, 187 void *bsm_data, size_t bsm_lenlen); 188 #endif 189 190 /* 191 * Kernel audit information. This will store the current audit address 192 * or host information that the kernel will use when it's generating 193 * audit records. This data is modified by the A_GET{SET}KAUDIT auditon(2) 194 * command. 195 */ 196 static struct auditinfo_addr audit_kinfo; 197 static struct rwlock audit_kinfo_lock; 198 199 #define KINFO_LOCK_INIT() rw_init(&audit_kinfo_lock, \ 200 "audit_kinfo_lock") 201 #define KINFO_RLOCK() rw_rlock(&audit_kinfo_lock) 202 #define KINFO_WLOCK() rw_wlock(&audit_kinfo_lock) 203 #define KINFO_RUNLOCK() rw_runlock(&audit_kinfo_lock) 204 #define KINFO_WUNLOCK() rw_wunlock(&audit_kinfo_lock) 205 206 /* 207 * Check various policies to see if we should enable system-call audit hooks. 208 * Note that despite the mutex being held, we want to assign a value exactly 209 * once, as checks of the flag are performed lock-free for performance 210 * reasons. The mutex is used to get a consistent snapshot of policy state -- 211 * e.g., safely accessing the two audit_trail flags. 212 */ 213 void 214 audit_syscalls_enabled_update(void) 215 { 216 217 mtx_lock(&audit_mtx); 218 #ifdef KDTRACE_HOOKS 219 if (audit_dtrace_enabled) 220 audit_syscalls_enabled = true; 221 else { 222 #endif 223 if (audit_trail_enabled && !audit_trail_suspended) 224 audit_syscalls_enabled = true; 225 else 226 audit_syscalls_enabled = false; 227 #ifdef KDTRACE_HOOKS 228 } 229 #endif 230 mtx_unlock(&audit_mtx); 231 } 232 233 void 234 audit_set_kinfo(struct auditinfo_addr *ak) 235 { 236 237 KASSERT(ak->ai_termid.at_type == AU_IPv4 || 238 ak->ai_termid.at_type == AU_IPv6, 239 ("audit_set_kinfo: invalid address type")); 240 241 KINFO_WLOCK(); 242 audit_kinfo = *ak; 243 KINFO_WUNLOCK(); 244 } 245 246 void 247 audit_get_kinfo(struct auditinfo_addr *ak) 248 { 249 250 KASSERT(audit_kinfo.ai_termid.at_type == AU_IPv4 || 251 audit_kinfo.ai_termid.at_type == AU_IPv6, 252 ("audit_set_kinfo: invalid address type")); 253 254 KINFO_RLOCK(); 255 *ak = audit_kinfo; 256 KINFO_RUNLOCK(); 257 } 258 259 /* 260 * Construct an audit record for the passed thread. 261 */ 262 static int 263 audit_record_ctor(void *mem, int size, void *arg, int flags) 264 { 265 struct kaudit_record *ar; 266 struct thread *td; 267 struct ucred *cred; 268 struct prison *pr; 269 270 KASSERT(sizeof(*ar) == size, ("audit_record_ctor: wrong size")); 271 272 td = arg; 273 ar = mem; 274 bzero(ar, sizeof(*ar)); 275 ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC; 276 nanotime(&ar->k_ar.ar_starttime); 277 278 /* 279 * Export the subject credential. 280 */ 281 cred = td->td_ucred; 282 cru2x(cred, &ar->k_ar.ar_subj_cred); 283 ar->k_ar.ar_subj_ruid = cred->cr_ruid; 284 ar->k_ar.ar_subj_rgid = cred->cr_rgid; 285 ar->k_ar.ar_subj_egid = cred->cr_groups[0]; 286 ar->k_ar.ar_subj_auid = cred->cr_audit.ai_auid; 287 ar->k_ar.ar_subj_asid = cred->cr_audit.ai_asid; 288 ar->k_ar.ar_subj_pid = td->td_proc->p_pid; 289 ar->k_ar.ar_subj_amask = cred->cr_audit.ai_mask; 290 ar->k_ar.ar_subj_term_addr = cred->cr_audit.ai_termid; 291 /* 292 * If this process is jailed, make sure we capture the name of the 293 * jail so we can use it to generate a zonename token when we covert 294 * this record to BSM. 295 */ 296 if (jailed(cred)) { 297 pr = cred->cr_prison; 298 (void) strlcpy(ar->k_ar.ar_jailname, pr->pr_name, 299 sizeof(ar->k_ar.ar_jailname)); 300 } else 301 ar->k_ar.ar_jailname[0] = '\0'; 302 return (0); 303 } 304 305 static void 306 audit_record_dtor(void *mem, int size, void *arg) 307 { 308 struct kaudit_record *ar; 309 310 KASSERT(sizeof(*ar) == size, ("audit_record_dtor: wrong size")); 311 312 ar = mem; 313 if (ar->k_ar.ar_arg_upath1 != NULL) 314 free(ar->k_ar.ar_arg_upath1, M_AUDITPATH); 315 if (ar->k_ar.ar_arg_upath2 != NULL) 316 free(ar->k_ar.ar_arg_upath2, M_AUDITPATH); 317 if (ar->k_ar.ar_arg_text != NULL) 318 free(ar->k_ar.ar_arg_text, M_AUDITTEXT); 319 if (ar->k_udata != NULL) 320 free(ar->k_udata, M_AUDITDATA); 321 if (ar->k_ar.ar_arg_argv != NULL) 322 free(ar->k_ar.ar_arg_argv, M_AUDITTEXT); 323 if (ar->k_ar.ar_arg_envv != NULL) 324 free(ar->k_ar.ar_arg_envv, M_AUDITTEXT); 325 if (ar->k_ar.ar_arg_groups.gidset != NULL) 326 free(ar->k_ar.ar_arg_groups.gidset, M_AUDITGIDSET); 327 } 328 329 /* 330 * Initialize the Audit subsystem: configuration state, work queue, 331 * synchronization primitives, worker thread, and trigger device node. Also 332 * call into the BSM assembly code to initialize it. 333 */ 334 static void 335 audit_init(void) 336 { 337 338 audit_trail_enabled = 0; 339 audit_trail_suspended = 0; 340 audit_syscalls_enabled = false; 341 audit_panic_on_write_fail = 0; 342 audit_fail_stop = 0; 343 audit_in_failure = 0; 344 audit_argv = 0; 345 audit_arge = 0; 346 347 audit_fstat.af_filesz = 0; /* '0' means unset, unbounded. */ 348 audit_fstat.af_currsz = 0; 349 audit_nae_mask.am_success = 0; 350 audit_nae_mask.am_failure = 0; 351 352 TAILQ_INIT(&audit_q); 353 audit_q_len = 0; 354 audit_pre_q_len = 0; 355 audit_qctrl.aq_hiwater = AQ_HIWATER; 356 audit_qctrl.aq_lowater = AQ_LOWATER; 357 audit_qctrl.aq_bufsz = AQ_BUFSZ; 358 audit_qctrl.aq_minfree = AU_FS_MINFREE; 359 360 audit_kinfo.ai_termid.at_type = AU_IPv4; 361 audit_kinfo.ai_termid.at_addr[0] = INADDR_ANY; 362 363 mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF); 364 KINFO_LOCK_INIT(); 365 cv_init(&audit_worker_cv, "audit_worker_cv"); 366 cv_init(&audit_watermark_cv, "audit_watermark_cv"); 367 cv_init(&audit_fail_cv, "audit_fail_cv"); 368 369 audit_record_zone = uma_zcreate("audit_record", 370 sizeof(struct kaudit_record), audit_record_ctor, 371 audit_record_dtor, NULL, NULL, UMA_ALIGN_PTR, 0); 372 373 /* First initialisation of audit_syscalls_enabled. */ 374 audit_syscalls_enabled_update(); 375 376 /* Initialize the BSM audit subsystem. */ 377 kau_init(); 378 379 audit_trigger_init(); 380 381 /* Register shutdown handler. */ 382 EVENTHANDLER_REGISTER(shutdown_pre_sync, audit_shutdown, NULL, 383 SHUTDOWN_PRI_FIRST); 384 385 /* Start audit worker thread. */ 386 audit_worker_init(); 387 } 388 389 SYSINIT(audit_init, SI_SUB_AUDIT, SI_ORDER_FIRST, audit_init, NULL); 390 391 /* 392 * Drain the audit queue and close the log at shutdown. Note that this can 393 * be called both from the system shutdown path and also from audit 394 * configuration syscalls, so 'arg' and 'howto' are ignored. 395 * 396 * XXXRW: In FreeBSD 7.x and 8.x, this fails to wait for the record queue to 397 * drain before returning, which could lead to lost records on shutdown. 398 */ 399 void 400 audit_shutdown(void *arg, int howto) 401 { 402 403 audit_rotate_vnode(NULL, NULL); 404 } 405 406 /* 407 * Return the current thread's audit record, if any. 408 */ 409 struct kaudit_record * 410 currecord(void) 411 { 412 413 return (curthread->td_ar); 414 } 415 416 /* 417 * XXXAUDIT: Shouldn't there be logic here to sleep waiting on available 418 * pre_q space, suspending the system call until there is room? 419 */ 420 struct kaudit_record * 421 audit_new(int event, struct thread *td) 422 { 423 struct kaudit_record *ar; 424 425 /* 426 * Note: the number of outstanding uncommitted audit records is 427 * limited to the number of concurrent threads servicing system calls 428 * in the kernel. 429 */ 430 ar = uma_zalloc_arg(audit_record_zone, td, M_WAITOK); 431 ar->k_ar.ar_event = event; 432 433 mtx_lock(&audit_mtx); 434 audit_pre_q_len++; 435 mtx_unlock(&audit_mtx); 436 437 return (ar); 438 } 439 440 void 441 audit_free(struct kaudit_record *ar) 442 { 443 444 uma_zfree(audit_record_zone, ar); 445 } 446 447 void 448 audit_commit(struct kaudit_record *ar, int error, int retval) 449 { 450 au_event_t event; 451 au_class_t class; 452 au_id_t auid; 453 int sorf; 454 struct au_mask *aumask; 455 456 if (ar == NULL) 457 return; 458 459 ar->k_ar.ar_errno = error; 460 ar->k_ar.ar_retval = retval; 461 nanotime(&ar->k_ar.ar_endtime); 462 463 /* 464 * Decide whether to commit the audit record by checking the error 465 * value from the system call and using the appropriate audit mask. 466 */ 467 if (ar->k_ar.ar_subj_auid == AU_DEFAUDITID) 468 aumask = &audit_nae_mask; 469 else 470 aumask = &ar->k_ar.ar_subj_amask; 471 472 if (error) 473 sorf = AU_PRS_FAILURE; 474 else 475 sorf = AU_PRS_SUCCESS; 476 477 /* 478 * syscalls.master sometimes contains a prototype event number, which 479 * we will transform into a more specific event number now that we 480 * have more complete information gathered during the system call. 481 */ 482 switch(ar->k_ar.ar_event) { 483 case AUE_OPEN_RWTC: 484 ar->k_ar.ar_event = audit_flags_and_error_to_openevent( 485 ar->k_ar.ar_arg_fflags, error); 486 break; 487 488 case AUE_OPENAT_RWTC: 489 ar->k_ar.ar_event = audit_flags_and_error_to_openatevent( 490 ar->k_ar.ar_arg_fflags, error); 491 break; 492 493 case AUE_SYSCTL: 494 ar->k_ar.ar_event = audit_ctlname_to_sysctlevent( 495 ar->k_ar.ar_arg_ctlname, ar->k_ar.ar_valid_arg); 496 break; 497 498 case AUE_AUDITON: 499 /* Convert the auditon() command to an event. */ 500 ar->k_ar.ar_event = auditon_command_event(ar->k_ar.ar_arg_cmd); 501 break; 502 503 case AUE_MSGSYS: 504 if (ARG_IS_VALID(ar, ARG_SVIPC_WHICH)) 505 ar->k_ar.ar_event = 506 audit_msgsys_to_event(ar->k_ar.ar_arg_svipc_which); 507 break; 508 509 case AUE_SEMSYS: 510 if (ARG_IS_VALID(ar, ARG_SVIPC_WHICH)) 511 ar->k_ar.ar_event = 512 audit_semsys_to_event(ar->k_ar.ar_arg_svipc_which); 513 break; 514 515 case AUE_SHMSYS: 516 if (ARG_IS_VALID(ar, ARG_SVIPC_WHICH)) 517 ar->k_ar.ar_event = 518 audit_shmsys_to_event(ar->k_ar.ar_arg_svipc_which); 519 break; 520 } 521 522 auid = ar->k_ar.ar_subj_auid; 523 event = ar->k_ar.ar_event; 524 class = au_event_class(event); 525 526 ar->k_ar_commit |= AR_COMMIT_KERNEL; 527 if (au_preselect(event, class, aumask, sorf) != 0) 528 ar->k_ar_commit |= AR_PRESELECT_TRAIL; 529 if (audit_pipe_preselect(auid, event, class, sorf, 530 ar->k_ar_commit & AR_PRESELECT_TRAIL) != 0) 531 ar->k_ar_commit |= AR_PRESELECT_PIPE; 532 #ifdef KDTRACE_HOOKS 533 /* 534 * Expose the audit record to DTrace, both to allow the "commit" probe 535 * to fire if it's desirable, and also to allow a decision to be made 536 * about later firing with BSM in the audit worker. 537 */ 538 if (dtaudit_hook_commit != NULL) { 539 if (dtaudit_hook_commit(ar, auid, event, class, sorf) != 0) 540 ar->k_ar_commit |= AR_PRESELECT_DTRACE; 541 } 542 #endif 543 544 if ((ar->k_ar_commit & (AR_PRESELECT_TRAIL | AR_PRESELECT_PIPE | 545 AR_PRESELECT_USER_TRAIL | AR_PRESELECT_USER_PIPE | 546 AR_PRESELECT_DTRACE)) == 0) { 547 mtx_lock(&audit_mtx); 548 audit_pre_q_len--; 549 mtx_unlock(&audit_mtx); 550 audit_free(ar); 551 return; 552 } 553 554 /* 555 * Note: it could be that some records initiated while audit was 556 * enabled should still be committed? 557 * 558 * NB: The check here is not for audit_syscalls because any 559 * DTrace-related obligations have been fulfilled above -- we're just 560 * down to the trail and pipes now. 561 */ 562 mtx_lock(&audit_mtx); 563 if (audit_trail_suspended || !audit_trail_enabled) { 564 audit_pre_q_len--; 565 mtx_unlock(&audit_mtx); 566 audit_free(ar); 567 return; 568 } 569 570 /* 571 * Constrain the number of committed audit records based on the 572 * configurable parameter. 573 */ 574 while (audit_q_len >= audit_qctrl.aq_hiwater) 575 cv_wait(&audit_watermark_cv, &audit_mtx); 576 577 TAILQ_INSERT_TAIL(&audit_q, ar, k_q); 578 audit_q_len++; 579 audit_pre_q_len--; 580 cv_signal(&audit_worker_cv); 581 mtx_unlock(&audit_mtx); 582 } 583 584 /* 585 * audit_syscall_enter() is called on entry to each system call. It is 586 * responsible for deciding whether or not to audit the call (preselection), 587 * and if so, allocating a per-thread audit record. audit_new() will fill in 588 * basic thread/credential properties. 589 * 590 * This function will be entered only if audit_syscalls_enabled was set in the 591 * macro wrapper for this function. It could be cleared by the time this 592 * function runs, but that is an acceptable race. 593 */ 594 void 595 audit_syscall_enter(unsigned short code, struct thread *td) 596 { 597 struct au_mask *aumask; 598 #ifdef KDTRACE_HOOKS 599 void *dtaudit_state; 600 #endif 601 au_class_t class; 602 au_event_t event; 603 au_id_t auid; 604 int record_needed; 605 606 KASSERT(td->td_ar == NULL, ("audit_syscall_enter: td->td_ar != NULL")); 607 KASSERT((td->td_pflags & TDP_AUDITREC) == 0, 608 ("audit_syscall_enter: TDP_AUDITREC set")); 609 610 /* 611 * In FreeBSD, each ABI has its own system call table, and hence 612 * mapping of system call codes to audit events. Convert the code to 613 * an audit event identifier using the process system call table 614 * reference. In Darwin, there's only one, so we use the global 615 * symbol for the system call table. No audit record is generated 616 * for bad system calls, as no operation has been performed. 617 */ 618 if (code >= td->td_proc->p_sysent->sv_size) 619 return; 620 621 event = td->td_proc->p_sysent->sv_table[code].sy_auevent; 622 if (event == AUE_NULL) 623 return; 624 625 /* 626 * Check which audit mask to use; either the kernel non-attributable 627 * event mask or the process audit mask. 628 */ 629 auid = td->td_ucred->cr_audit.ai_auid; 630 if (auid == AU_DEFAUDITID) 631 aumask = &audit_nae_mask; 632 else 633 aumask = &td->td_ucred->cr_audit.ai_mask; 634 635 /* 636 * Determine whether trail or pipe preselection would like an audit 637 * record allocated for this system call. 638 */ 639 class = au_event_class(event); 640 if (au_preselect(event, class, aumask, AU_PRS_BOTH)) { 641 /* 642 * If we're out of space and need to suspend unprivileged 643 * processes, do that here rather than trying to allocate 644 * another audit record. 645 * 646 * Note: we might wish to be able to continue here in the 647 * future, if the system recovers. That should be possible 648 * by means of checking the condition in a loop around 649 * cv_wait(). It might be desirable to reevaluate whether an 650 * audit record is still required for this event by 651 * re-calling au_preselect(). 652 */ 653 if (audit_in_failure && 654 priv_check(td, PRIV_AUDIT_FAILSTOP) != 0) { 655 cv_wait(&audit_fail_cv, &audit_mtx); 656 panic("audit_failing_stop: thread continued"); 657 } 658 record_needed = 1; 659 } else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) { 660 record_needed = 1; 661 } else { 662 record_needed = 0; 663 } 664 665 /* 666 * After audit trails and pipes have made their policy choices, DTrace 667 * may request that records be generated as well. This is a slightly 668 * complex affair, as the DTrace audit provider needs the audit 669 * framework to maintain some state on the audit record, which has not 670 * been allocated at the point where the decision has to be made. 671 * This hook must run even if we are not changing the decision, as 672 * DTrace may want to stick event state onto a record we were going to 673 * produce due to the trail or pipes. The event state returned by the 674 * DTrace provider must be safe without locks held between here and 675 * below -- i.e., dtaudit_state must must refer to stable memory. 676 */ 677 #ifdef KDTRACE_HOOKS 678 dtaudit_state = NULL; 679 if (dtaudit_hook_preselect != NULL) { 680 dtaudit_state = dtaudit_hook_preselect(auid, event, class); 681 if (dtaudit_state != NULL) 682 record_needed = 1; 683 } 684 #endif 685 686 /* 687 * If a record is required, allocate it and attach it to the thread 688 * for use throughout the system call. Also attach DTrace state if 689 * required. 690 * 691 * XXXRW: If we decide to reference count the evname_elem underlying 692 * dtaudit_state, we will need to free here if no record is allocated 693 * or allocatable. 694 */ 695 if (record_needed) { 696 td->td_ar = audit_new(event, td); 697 if (td->td_ar != NULL) { 698 td->td_pflags |= TDP_AUDITREC; 699 #ifdef KDTRACE_HOOKS 700 td->td_ar->k_dtaudit_state = dtaudit_state; 701 #endif 702 } 703 } else 704 td->td_ar = NULL; 705 } 706 707 /* 708 * audit_syscall_exit() is called from the return of every system call, or in 709 * the event of exit1(), during the execution of exit1(). It is responsible 710 * for committing the audit record, if any, along with return condition. 711 */ 712 void 713 audit_syscall_exit(int error, struct thread *td) 714 { 715 int retval; 716 717 /* 718 * Commit the audit record as desired; once we pass the record into 719 * audit_commit(), the memory is owned by the audit subsystem. The 720 * return value from the system call is stored on the user thread. 721 * If there was an error, the return value is set to -1, imitating 722 * the behavior of the cerror routine. 723 */ 724 if (error) 725 retval = -1; 726 else 727 retval = td->td_retval[0]; 728 729 audit_commit(td->td_ar, error, retval); 730 td->td_ar = NULL; 731 td->td_pflags &= ~TDP_AUDITREC; 732 } 733 734 void 735 audit_cred_copy(struct ucred *src, struct ucred *dest) 736 { 737 738 bcopy(&src->cr_audit, &dest->cr_audit, sizeof(dest->cr_audit)); 739 } 740 741 void 742 audit_cred_destroy(struct ucred *cred) 743 { 744 745 } 746 747 void 748 audit_cred_init(struct ucred *cred) 749 { 750 751 bzero(&cred->cr_audit, sizeof(cred->cr_audit)); 752 } 753 754 /* 755 * Initialize audit information for the first kernel process (proc 0) and for 756 * the first user process (init). 757 */ 758 void 759 audit_cred_kproc0(struct ucred *cred) 760 { 761 762 cred->cr_audit.ai_auid = AU_DEFAUDITID; 763 cred->cr_audit.ai_termid.at_type = AU_IPv4; 764 } 765 766 void 767 audit_cred_proc1(struct ucred *cred) 768 { 769 770 cred->cr_audit.ai_auid = AU_DEFAUDITID; 771 cred->cr_audit.ai_termid.at_type = AU_IPv4; 772 } 773 774 void 775 audit_thread_alloc(struct thread *td) 776 { 777 778 td->td_ar = NULL; 779 } 780 781 void 782 audit_thread_free(struct thread *td) 783 { 784 785 KASSERT(td->td_ar == NULL, ("audit_thread_free: td_ar != NULL")); 786 KASSERT((td->td_pflags & TDP_AUDITREC) == 0, 787 ("audit_thread_free: TDP_AUDITREC set")); 788 } 789 790 void 791 audit_proc_coredump(struct thread *td, char *path, int errcode) 792 { 793 struct kaudit_record *ar; 794 struct au_mask *aumask; 795 struct ucred *cred; 796 au_class_t class; 797 int ret, sorf; 798 char **pathp; 799 au_id_t auid; 800 801 ret = 0; 802 803 /* 804 * Make sure we are using the correct preselection mask. 805 */ 806 cred = td->td_ucred; 807 auid = cred->cr_audit.ai_auid; 808 if (auid == AU_DEFAUDITID) 809 aumask = &audit_nae_mask; 810 else 811 aumask = &cred->cr_audit.ai_mask; 812 /* 813 * It's possible for coredump(9) generation to fail. Make sure that 814 * we handle this case correctly for preselection. 815 */ 816 if (errcode != 0) 817 sorf = AU_PRS_FAILURE; 818 else 819 sorf = AU_PRS_SUCCESS; 820 class = au_event_class(AUE_CORE); 821 if (au_preselect(AUE_CORE, class, aumask, sorf) == 0 && 822 audit_pipe_preselect(auid, AUE_CORE, class, sorf, 0) == 0) 823 return; 824 825 /* 826 * If we are interested in seeing this audit record, allocate it. 827 * Where possible coredump records should contain a pathname and arg32 828 * (signal) tokens. 829 */ 830 ar = audit_new(AUE_CORE, td); 831 if (ar == NULL) 832 return; 833 if (path != NULL) { 834 pathp = &ar->k_ar.ar_arg_upath1; 835 *pathp = malloc(MAXPATHLEN, M_AUDITPATH, M_WAITOK); 836 audit_canon_path(td, AT_FDCWD, path, *pathp); 837 ARG_SET_VALID(ar, ARG_UPATH1); 838 } 839 ar->k_ar.ar_arg_signum = td->td_proc->p_sig; 840 ARG_SET_VALID(ar, ARG_SIGNUM); 841 if (errcode != 0) 842 ret = 1; 843 audit_commit(ar, errcode, ret); 844 } 845