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