The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/security/audit/audit.c

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    1 /*-
    2  * Copyright (c) 1999-2005 Apple Inc.
    3  * Copyright (c) 2006-2007 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/condvar.h>
   36 #include <sys/conf.h>
   37 #include <sys/file.h>
   38 #include <sys/filedesc.h>
   39 #include <sys/fcntl.h>
   40 #include <sys/ipc.h>
   41 #include <sys/kernel.h>
   42 #include <sys/kthread.h>
   43 #include <sys/malloc.h>
   44 #include <sys/mount.h>
   45 #include <sys/namei.h>
   46 #include <sys/priv.h>
   47 #include <sys/proc.h>
   48 #include <sys/queue.h>
   49 #include <sys/socket.h>
   50 #include <sys/socketvar.h>
   51 #include <sys/protosw.h>
   52 #include <sys/domain.h>
   53 #include <sys/sysctl.h>
   54 #include <sys/sysproto.h>
   55 #include <sys/sysent.h>
   56 #include <sys/systm.h>
   57 #include <sys/ucred.h>
   58 #include <sys/uio.h>
   59 #include <sys/un.h>
   60 #include <sys/unistd.h>
   61 #include <sys/vnode.h>
   62 
   63 #include <bsm/audit.h>
   64 #include <bsm/audit_internal.h>
   65 #include <bsm/audit_kevents.h>
   66 
   67 #include <netinet/in.h>
   68 #include <netinet/in_pcb.h>
   69 
   70 #include <security/audit/audit.h>
   71 #include <security/audit/audit_private.h>
   72 
   73 #include <vm/uma.h>
   74 
   75 FEATURE(audit, "BSM audit support");
   76 
   77 static uma_zone_t       audit_record_zone;
   78 static MALLOC_DEFINE(M_AUDITCRED, "audit_cred", "Audit cred storage");
   79 MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage");
   80 MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage");
   81 MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage");
   82 MALLOC_DEFINE(M_AUDITGIDSET, "audit_gidset", "Audit GID set storage");
   83 
   84 static SYSCTL_NODE(_security, OID_AUTO, audit, CTLFLAG_RW, 0,
   85     "TrustedBSD audit controls");
   86 
   87 /*
   88  * Audit control settings that are set/read by system calls and are hence
   89  * non-static.
   90  *
   91  * Define the audit control flags.
   92  */
   93 int                     audit_enabled;
   94 int                     audit_suspended;
   95 
   96 /*
   97  * Flags controlling behavior in low storage situations.  Should we panic if
   98  * a write fails?  Should we fail stop if we're out of disk space?
   99  */
  100 int                     audit_panic_on_write_fail;
  101 int                     audit_fail_stop;
  102 int                     audit_argv;
  103 int                     audit_arge;
  104 
  105 /*
  106  * Are we currently "failing stop" due to out of disk space?
  107  */
  108 int                     audit_in_failure;
  109 
  110 /*
  111  * Global audit statistics.
  112  */
  113 struct audit_fstat      audit_fstat;
  114 
  115 /*
  116  * Preselection mask for non-attributable events.
  117  */
  118 struct au_mask          audit_nae_mask;
  119 
  120 /*
  121  * Mutex to protect global variables shared between various threads and
  122  * processes.
  123  */
  124 struct mtx              audit_mtx;
  125 
  126 /*
  127  * Queue of audit records ready for delivery to disk.  We insert new records
  128  * at the tail, and remove records from the head.  Also, a count of the
  129  * number of records used for checking queue depth.  In addition, a counter
  130  * of records that we have allocated but are not yet in the queue, which is
  131  * needed to estimate the total size of the combined set of records
  132  * outstanding in the system.
  133  */
  134 struct kaudit_queue     audit_q;
  135 int                     audit_q_len;
  136 int                     audit_pre_q_len;
  137 
  138 /*
  139  * Audit queue control settings (minimum free, low/high water marks, etc.)
  140  */
  141 struct au_qctrl         audit_qctrl;
  142 
  143 /*
  144  * Condition variable to signal to the worker that it has work to do: either
  145  * new records are in the queue, or a log replacement is taking place.
  146  */
  147 struct cv               audit_worker_cv;
  148 
  149 /*
  150  * Condition variable to flag when crossing the low watermark, meaning that
  151  * threads blocked due to hitting the high watermark can wake up and continue
  152  * to commit records.
  153  */
  154 struct cv               audit_watermark_cv;
  155 
  156 /*
  157  * Condition variable for  auditing threads wait on when in fail-stop mode.
  158  * Threads wait on this CV forever (and ever), never seeing the light of day
  159  * again.
  160  */
  161 static struct cv        audit_fail_cv;
  162 
  163 /*
  164  * Kernel audit information.  This will store the current audit address
  165  * or host information that the kernel will use when it's generating
  166  * audit records.  This data is modified by the A_GET{SET}KAUDIT auditon(2)
  167  * command.
  168  */
  169 static struct auditinfo_addr    audit_kinfo;
  170 static struct rwlock            audit_kinfo_lock;
  171 
  172 #define KINFO_LOCK_INIT()       rw_init(&audit_kinfo_lock, \
  173                                     "audit_kinfo_lock")
  174 #define KINFO_RLOCK()           rw_rlock(&audit_kinfo_lock)
  175 #define KINFO_WLOCK()           rw_wlock(&audit_kinfo_lock)
  176 #define KINFO_RUNLOCK()         rw_runlock(&audit_kinfo_lock)
  177 #define KINFO_WUNLOCK()         rw_wunlock(&audit_kinfo_lock)
  178 
  179 void
  180 audit_set_kinfo(struct auditinfo_addr *ak)
  181 {
  182 
  183         KASSERT(ak->ai_termid.at_type == AU_IPv4 ||
  184             ak->ai_termid.at_type == AU_IPv6,
  185             ("audit_set_kinfo: invalid address type"));
  186 
  187         KINFO_WLOCK();
  188         audit_kinfo = *ak;
  189         KINFO_WUNLOCK();
  190 }
  191 
  192 void
  193 audit_get_kinfo(struct auditinfo_addr *ak)
  194 {
  195 
  196         KASSERT(audit_kinfo.ai_termid.at_type == AU_IPv4 ||
  197             audit_kinfo.ai_termid.at_type == AU_IPv6,
  198             ("audit_set_kinfo: invalid address type"));
  199 
  200         KINFO_RLOCK();
  201         *ak = audit_kinfo;
  202         KINFO_RUNLOCK();
  203 }
  204 
  205 /*
  206  * Construct an audit record for the passed thread.
  207  */
  208 static int
  209 audit_record_ctor(void *mem, int size, void *arg, int flags)
  210 {
  211         struct kaudit_record *ar;
  212         struct thread *td;
  213         struct ucred *cred;
  214 
  215         KASSERT(sizeof(*ar) == size, ("audit_record_ctor: wrong size"));
  216 
  217         td = arg;
  218         ar = mem;
  219         bzero(ar, sizeof(*ar));
  220         ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC;
  221         nanotime(&ar->k_ar.ar_starttime);
  222 
  223         /*
  224          * Export the subject credential.
  225          */
  226         cred = td->td_ucred;
  227         cru2x(cred, &ar->k_ar.ar_subj_cred);
  228         ar->k_ar.ar_subj_ruid = cred->cr_ruid;
  229         ar->k_ar.ar_subj_rgid = cred->cr_rgid;
  230         ar->k_ar.ar_subj_egid = cred->cr_groups[0];
  231         ar->k_ar.ar_subj_auid = cred->cr_audit.ai_auid;
  232         ar->k_ar.ar_subj_asid = cred->cr_audit.ai_asid;
  233         ar->k_ar.ar_subj_pid = td->td_proc->p_pid;
  234         ar->k_ar.ar_subj_amask = cred->cr_audit.ai_mask;
  235         ar->k_ar.ar_subj_term_addr = cred->cr_audit.ai_termid;
  236         return (0);
  237 }
  238 
  239 static void
  240 audit_record_dtor(void *mem, int size, void *arg)
  241 {
  242         struct kaudit_record *ar;
  243 
  244         KASSERT(sizeof(*ar) == size, ("audit_record_dtor: wrong size"));
  245 
  246         ar = mem;
  247         if (ar->k_ar.ar_arg_upath1 != NULL)
  248                 free(ar->k_ar.ar_arg_upath1, M_AUDITPATH);
  249         if (ar->k_ar.ar_arg_upath2 != NULL)
  250                 free(ar->k_ar.ar_arg_upath2, M_AUDITPATH);
  251         if (ar->k_ar.ar_arg_text != NULL)
  252                 free(ar->k_ar.ar_arg_text, M_AUDITTEXT);
  253         if (ar->k_udata != NULL)
  254                 free(ar->k_udata, M_AUDITDATA);
  255         if (ar->k_ar.ar_arg_argv != NULL)
  256                 free(ar->k_ar.ar_arg_argv, M_AUDITTEXT);
  257         if (ar->k_ar.ar_arg_envv != NULL)
  258                 free(ar->k_ar.ar_arg_envv, M_AUDITTEXT);
  259         if (ar->k_ar.ar_arg_groups.gidset != NULL)
  260                 free(ar->k_ar.ar_arg_groups.gidset, M_AUDITGIDSET);
  261 }
  262 
  263 /*
  264  * Initialize the Audit subsystem: configuration state, work queue,
  265  * synchronization primitives, worker thread, and trigger device node.  Also
  266  * call into the BSM assembly code to initialize it.
  267  */
  268 static void
  269 audit_init(void)
  270 {
  271 
  272         audit_enabled = 0;
  273         audit_suspended = 0;
  274         audit_panic_on_write_fail = 0;
  275         audit_fail_stop = 0;
  276         audit_in_failure = 0;
  277         audit_argv = 0;
  278         audit_arge = 0;
  279 
  280         audit_fstat.af_filesz = 0;      /* '' means unset, unbounded. */
  281         audit_fstat.af_currsz = 0;
  282         audit_nae_mask.am_success = 0;
  283         audit_nae_mask.am_failure = 0;
  284 
  285         TAILQ_INIT(&audit_q);
  286         audit_q_len = 0;
  287         audit_pre_q_len = 0;
  288         audit_qctrl.aq_hiwater = AQ_HIWATER;
  289         audit_qctrl.aq_lowater = AQ_LOWATER;
  290         audit_qctrl.aq_bufsz = AQ_BUFSZ;
  291         audit_qctrl.aq_minfree = AU_FS_MINFREE;
  292 
  293         audit_kinfo.ai_termid.at_type = AU_IPv4;
  294         audit_kinfo.ai_termid.at_addr[0] = INADDR_ANY;
  295 
  296         mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF);
  297         KINFO_LOCK_INIT();
  298         cv_init(&audit_worker_cv, "audit_worker_cv");
  299         cv_init(&audit_watermark_cv, "audit_watermark_cv");
  300         cv_init(&audit_fail_cv, "audit_fail_cv");
  301 
  302         audit_record_zone = uma_zcreate("audit_record",
  303             sizeof(struct kaudit_record), audit_record_ctor,
  304             audit_record_dtor, NULL, NULL, UMA_ALIGN_PTR, 0);
  305 
  306         /* Initialize the BSM audit subsystem. */
  307         kau_init();
  308 
  309         audit_trigger_init();
  310 
  311         /* Register shutdown handler. */
  312         EVENTHANDLER_REGISTER(shutdown_pre_sync, audit_shutdown, NULL,
  313             SHUTDOWN_PRI_FIRST);
  314 
  315         /* Start audit worker thread. */
  316         audit_worker_init();
  317 }
  318 
  319 SYSINIT(audit_init, SI_SUB_AUDIT, SI_ORDER_FIRST, audit_init, NULL);
  320 
  321 /*
  322  * Drain the audit queue and close the log at shutdown.  Note that this can
  323  * be called both from the system shutdown path and also from audit
  324  * configuration syscalls, so 'arg' and 'howto' are ignored.
  325  *
  326  * XXXRW: In FreeBSD 7.x and 8.x, this fails to wait for the record queue to
  327  * drain before returning, which could lead to lost records on shutdown.
  328  */
  329 void
  330 audit_shutdown(void *arg, int howto)
  331 {
  332 
  333         audit_rotate_vnode(NULL, NULL);
  334 }
  335 
  336 /*
  337  * Return the current thread's audit record, if any.
  338  */
  339 struct kaudit_record *
  340 currecord(void)
  341 {
  342 
  343         return (curthread->td_ar);
  344 }
  345 
  346 /*
  347  * XXXAUDIT: There are a number of races present in the code below due to
  348  * release and re-grab of the mutex.  The code should be revised to become
  349  * slightly less racy.
  350  *
  351  * XXXAUDIT: Shouldn't there be logic here to sleep waiting on available
  352  * pre_q space, suspending the system call until there is room?
  353  */
  354 struct kaudit_record *
  355 audit_new(int event, struct thread *td)
  356 {
  357         struct kaudit_record *ar;
  358         int no_record;
  359 
  360         mtx_lock(&audit_mtx);
  361         no_record = (audit_suspended || !audit_enabled);
  362         mtx_unlock(&audit_mtx);
  363         if (no_record)
  364                 return (NULL);
  365 
  366         /*
  367          * Note: the number of outstanding uncommitted audit records is
  368          * limited to the number of concurrent threads servicing system calls
  369          * in the kernel.
  370          */
  371         ar = uma_zalloc_arg(audit_record_zone, td, M_WAITOK);
  372         ar->k_ar.ar_event = event;
  373 
  374         mtx_lock(&audit_mtx);
  375         audit_pre_q_len++;
  376         mtx_unlock(&audit_mtx);
  377 
  378         return (ar);
  379 }
  380 
  381 void
  382 audit_free(struct kaudit_record *ar)
  383 {
  384 
  385         uma_zfree(audit_record_zone, ar);
  386 }
  387 
  388 void
  389 audit_commit(struct kaudit_record *ar, int error, int retval)
  390 {
  391         au_event_t event;
  392         au_class_t class;
  393         au_id_t auid;
  394         int sorf;
  395         struct au_mask *aumask;
  396 
  397         if (ar == NULL)
  398                 return;
  399 
  400         /*
  401          * Decide whether to commit the audit record by checking the error
  402          * value from the system call and using the appropriate audit mask.
  403          */
  404         if (ar->k_ar.ar_subj_auid == AU_DEFAUDITID)
  405                 aumask = &audit_nae_mask;
  406         else
  407                 aumask = &ar->k_ar.ar_subj_amask;
  408 
  409         if (error)
  410                 sorf = AU_PRS_FAILURE;
  411         else
  412                 sorf = AU_PRS_SUCCESS;
  413 
  414         /*
  415          * syscalls.master sometimes contains a prototype event number, which
  416          * we will transform into a more specific event number now that we
  417          * have more complete information gathered during the system call.
  418          */
  419         switch(ar->k_ar.ar_event) {
  420         case AUE_OPEN_RWTC:
  421                 ar->k_ar.ar_event = audit_flags_and_error_to_openevent(
  422                     ar->k_ar.ar_arg_fflags, error);
  423                 break;
  424 
  425         case AUE_OPENAT_RWTC:
  426                 ar->k_ar.ar_event = audit_flags_and_error_to_openatevent(
  427                     ar->k_ar.ar_arg_fflags, error);
  428                 break;
  429 
  430         case AUE_SYSCTL:
  431                 ar->k_ar.ar_event = audit_ctlname_to_sysctlevent(
  432                     ar->k_ar.ar_arg_ctlname, ar->k_ar.ar_valid_arg);
  433                 break;
  434 
  435         case AUE_AUDITON:
  436                 /* Convert the auditon() command to an event. */
  437                 ar->k_ar.ar_event = auditon_command_event(ar->k_ar.ar_arg_cmd);
  438                 break;
  439         }
  440 
  441         auid = ar->k_ar.ar_subj_auid;
  442         event = ar->k_ar.ar_event;
  443         class = au_event_class(event);
  444 
  445         ar->k_ar_commit |= AR_COMMIT_KERNEL;
  446         if (au_preselect(event, class, aumask, sorf) != 0)
  447                 ar->k_ar_commit |= AR_PRESELECT_TRAIL;
  448         if (audit_pipe_preselect(auid, event, class, sorf,
  449             ar->k_ar_commit & AR_PRESELECT_TRAIL) != 0)
  450                 ar->k_ar_commit |= AR_PRESELECT_PIPE;
  451         if ((ar->k_ar_commit & (AR_PRESELECT_TRAIL | AR_PRESELECT_PIPE |
  452             AR_PRESELECT_USER_TRAIL | AR_PRESELECT_USER_PIPE)) == 0) {
  453                 mtx_lock(&audit_mtx);
  454                 audit_pre_q_len--;
  455                 mtx_unlock(&audit_mtx);
  456                 audit_free(ar);
  457                 return;
  458         }
  459 
  460         ar->k_ar.ar_errno = error;
  461         ar->k_ar.ar_retval = retval;
  462         nanotime(&ar->k_ar.ar_endtime);
  463 
  464         /*
  465          * Note: it could be that some records initiated while audit was
  466          * enabled should still be committed?
  467          */
  468         mtx_lock(&audit_mtx);
  469         if (audit_suspended || !audit_enabled) {
  470                 audit_pre_q_len--;
  471                 mtx_unlock(&audit_mtx);
  472                 audit_free(ar);
  473                 return;
  474         }
  475 
  476         /*
  477          * Constrain the number of committed audit records based on the
  478          * configurable parameter.
  479          */
  480         while (audit_q_len >= audit_qctrl.aq_hiwater)
  481                 cv_wait(&audit_watermark_cv, &audit_mtx);
  482 
  483         TAILQ_INSERT_TAIL(&audit_q, ar, k_q);
  484         audit_q_len++;
  485         audit_pre_q_len--;
  486         cv_signal(&audit_worker_cv);
  487         mtx_unlock(&audit_mtx);
  488 }
  489 
  490 /*
  491  * audit_syscall_enter() is called on entry to each system call.  It is
  492  * responsible for deciding whether or not to audit the call (preselection),
  493  * and if so, allocating a per-thread audit record.  audit_new() will fill in
  494  * basic thread/credential properties.
  495  */
  496 void
  497 audit_syscall_enter(unsigned short code, struct thread *td)
  498 {
  499         struct au_mask *aumask;
  500         au_class_t class;
  501         au_event_t event;
  502         au_id_t auid;
  503 
  504         KASSERT(td->td_ar == NULL, ("audit_syscall_enter: td->td_ar != NULL"));
  505         KASSERT((td->td_pflags & TDP_AUDITREC) == 0,
  506             ("audit_syscall_enter: TDP_AUDITREC set"));
  507 
  508         /*
  509          * In FreeBSD, each ABI has its own system call table, and hence
  510          * mapping of system call codes to audit events.  Convert the code to
  511          * an audit event identifier using the process system call table
  512          * reference.  In Darwin, there's only one, so we use the global
  513          * symbol for the system call table.  No audit record is generated
  514          * for bad system calls, as no operation has been performed.
  515          */
  516         if (code >= td->td_proc->p_sysent->sv_size)
  517                 return;
  518 
  519         event = td->td_proc->p_sysent->sv_table[code].sy_auevent;
  520         if (event == AUE_NULL)
  521                 return;
  522 
  523         /*
  524          * Check which audit mask to use; either the kernel non-attributable
  525          * event mask or the process audit mask.
  526          */
  527         auid = td->td_ucred->cr_audit.ai_auid;
  528         if (auid == AU_DEFAUDITID)
  529                 aumask = &audit_nae_mask;
  530         else
  531                 aumask = &td->td_ucred->cr_audit.ai_mask;
  532 
  533         /*
  534          * Allocate an audit record, if preselection allows it, and store in
  535          * the thread for later use.
  536          */
  537         class = au_event_class(event);
  538         if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
  539                 /*
  540                  * If we're out of space and need to suspend unprivileged
  541                  * processes, do that here rather than trying to allocate
  542                  * another audit record.
  543                  *
  544                  * Note: we might wish to be able to continue here in the
  545                  * future, if the system recovers.  That should be possible
  546                  * by means of checking the condition in a loop around
  547                  * cv_wait().  It might be desirable to reevaluate whether an
  548                  * audit record is still required for this event by
  549                  * re-calling au_preselect().
  550                  */
  551                 if (audit_in_failure &&
  552                     priv_check(td, PRIV_AUDIT_FAILSTOP) != 0) {
  553                         cv_wait(&audit_fail_cv, &audit_mtx);
  554                         panic("audit_failing_stop: thread continued");
  555                 }
  556                 td->td_ar = audit_new(event, td);
  557                 if (td->td_ar != NULL)
  558                         td->td_pflags |= TDP_AUDITREC;
  559         } else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
  560                 td->td_ar = audit_new(event, td);
  561                 if (td->td_ar != NULL)
  562                         td->td_pflags |= TDP_AUDITREC;
  563         } else
  564                 td->td_ar = NULL;
  565 }
  566 
  567 /*
  568  * audit_syscall_exit() is called from the return of every system call, or in
  569  * the event of exit1(), during the execution of exit1().  It is responsible
  570  * for committing the audit record, if any, along with return condition.
  571  */
  572 void
  573 audit_syscall_exit(int error, struct thread *td)
  574 {
  575         int retval;
  576 
  577         /*
  578          * Commit the audit record as desired; once we pass the record into
  579          * audit_commit(), the memory is owned by the audit subsystem.  The
  580          * return value from the system call is stored on the user thread.
  581          * If there was an error, the return value is set to -1, imitating
  582          * the behavior of the cerror routine.
  583          */
  584         if (error)
  585                 retval = -1;
  586         else
  587                 retval = td->td_retval[0];
  588 
  589         audit_commit(td->td_ar, error, retval);
  590         td->td_ar = NULL;
  591         td->td_pflags &= ~TDP_AUDITREC;
  592 }
  593 
  594 void
  595 audit_cred_copy(struct ucred *src, struct ucred *dest)
  596 {
  597 
  598         bcopy(&src->cr_audit, &dest->cr_audit, sizeof(dest->cr_audit));
  599 }
  600 
  601 void
  602 audit_cred_destroy(struct ucred *cred)
  603 {
  604 
  605 }
  606 
  607 void
  608 audit_cred_init(struct ucred *cred)
  609 {
  610 
  611         bzero(&cred->cr_audit, sizeof(cred->cr_audit));
  612 }
  613 
  614 /*
  615  * Initialize audit information for the first kernel process (proc 0) and for
  616  * the first user process (init).
  617  */
  618 void
  619 audit_cred_kproc0(struct ucred *cred)
  620 {
  621 
  622         cred->cr_audit.ai_auid = AU_DEFAUDITID;
  623         cred->cr_audit.ai_termid.at_type = AU_IPv4;
  624 }
  625 
  626 void
  627 audit_cred_proc1(struct ucred *cred)
  628 {
  629 
  630         cred->cr_audit.ai_auid = AU_DEFAUDITID;
  631         cred->cr_audit.ai_termid.at_type = AU_IPv4;
  632 }
  633 
  634 void
  635 audit_thread_alloc(struct thread *td)
  636 {
  637 
  638         td->td_ar = NULL;
  639 }
  640 
  641 void
  642 audit_thread_free(struct thread *td)
  643 {
  644 
  645         KASSERT(td->td_ar == NULL, ("audit_thread_free: td_ar != NULL"));
  646         KASSERT((td->td_pflags & TDP_AUDITREC) == 0,
  647             ("audit_thread_free: TDP_AUDITREC set"));
  648 }
  649 
  650 void
  651 audit_proc_coredump(struct thread *td, char *path, int errcode)
  652 {
  653         struct kaudit_record *ar;
  654         struct au_mask *aumask;
  655         struct ucred *cred;
  656         au_class_t class;
  657         int ret, sorf;
  658         char **pathp;
  659         au_id_t auid;
  660 
  661         ret = 0;
  662 
  663         /*
  664          * Make sure we are using the correct preselection mask.
  665          */
  666         cred = td->td_ucred;
  667         auid = cred->cr_audit.ai_auid;
  668         if (auid == AU_DEFAUDITID)
  669                 aumask = &audit_nae_mask;
  670         else
  671                 aumask = &cred->cr_audit.ai_mask;
  672         /*
  673          * It's possible for coredump(9) generation to fail.  Make sure that
  674          * we handle this case correctly for preselection.
  675          */
  676         if (errcode != 0)
  677                 sorf = AU_PRS_FAILURE;
  678         else
  679                 sorf = AU_PRS_SUCCESS;
  680         class = au_event_class(AUE_CORE);
  681         if (au_preselect(AUE_CORE, class, aumask, sorf) == 0 &&
  682             audit_pipe_preselect(auid, AUE_CORE, class, sorf, 0) == 0)
  683                 return;
  684 
  685         /*
  686          * If we are interested in seeing this audit record, allocate it.
  687          * Where possible coredump records should contain a pathname and arg32
  688          * (signal) tokens.
  689          */
  690         ar = audit_new(AUE_CORE, td);
  691         if (ar == NULL)
  692                 return;
  693         if (path != NULL) {
  694                 pathp = &ar->k_ar.ar_arg_upath1;
  695                 *pathp = malloc(MAXPATHLEN, M_AUDITPATH, M_WAITOK);
  696                 audit_canon_path(td, AT_FDCWD, path, *pathp);
  697                 ARG_SET_VALID(ar, ARG_UPATH1);
  698         }
  699         ar->k_ar.ar_arg_signum = td->td_proc->p_sig;
  700         ARG_SET_VALID(ar, ARG_SIGNUM);
  701         if (errcode != 0)
  702                 ret = 1;
  703         audit_commit(ar, errcode, ret);
  704 }

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