/*-
* Copyright (c) 1999-2020 Apple Inc.
* Copyright (c) 2006-2007 Robert N. M. Watson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
/*
* NOTICE: This file was modified by McAfee Research in 2004 to introduce
* support for mandatory and extensible security protections. This notice
* is included in support of clause 2.2 (b) of the Apple Public License,
* Version 2.0.
*/
#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/namei.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/queue.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/ucred.h>
#include <sys/uio.h>
#include <sys/unistd.h>
#include <sys/file_internal.h>
#include <sys/vnode_internal.h>
#include <sys/user.h>
#include <sys/syscall.h>
#include <sys/un.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/vfs_context.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socketvar.h>
#include <bsm/audit.h>
#include <bsm/audit_internal.h>
#include <bsm/audit_kevents.h>
#include <security/audit/audit.h>
#include <security/audit/audit_bsd.h>
#include <security/audit/audit_private.h>
#include <mach/host_priv.h>
#include <mach/host_special_ports.h>
#include <mach/audit_triggers_server.h>
#include <kern/host.h>
#include <kern/zalloc.h>
#include <kern/sched_prim.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#if CONFIG_AUDIT
MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage");
MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage");
MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage");
/*
* Audit control settings that are set/read by system calls and are hence
* non-static.
*
* Define the audit control flags.
*/
int audit_enabled;
int audit_suspended;
int audit_syscalls;
au_class_t audit_kevent_mask;
/*
* The audit control mode is used to ensure configuration settings are only
* accepted from appropriate sources based on the current mode.
*/
au_ctlmode_t audit_ctl_mode;
au_expire_after_t audit_expire_after;
/*
* Flags controlling behavior in low storage situations. Should we panic if
* a write fails? Should we fail stop if we're out of disk space?
*/
int audit_panic_on_write_fail;
int audit_fail_stop;
int audit_argv;
int audit_arge;
/*
* Are we currently "failing stop" due to out of disk space?
*/
int audit_in_failure;
/*
* Global audit statistics.
*/
struct audit_fstat audit_fstat;
/*
* Preselection mask for non-attributable events.
*/
struct au_mask audit_nae_mask;
/*
* Mutex to protect global variables shared between various threads and
* processes.
*/
struct mtx audit_mtx;
/*
* Queue of audit records ready for delivery to disk. We insert new records
* at the tail, and remove records from the head. Also, a count of the
* number of records used for checking queue depth. In addition, a counter
* of records that we have allocated but are not yet in the queue, which is
* needed to estimate the total size of the combined set of records
* outstanding in the system.
*/
struct kaudit_queue audit_q;
int audit_q_len;
int audit_pre_q_len;
/*
* Audit queue control settings (minimum free, low/high water marks, etc.)
*/
struct au_qctrl audit_qctrl;
/*
* Condition variable to signal to the worker that it has work to do: either
* new records are in the queue, or a log replacement is taking place.
*/
struct cv audit_worker_cv;
/*
* Condition variable to signal when the worker is done draining the audit
* queue.
*/
struct cv audit_drain_cv;
/*
* Condition variable to flag when crossing the low watermark, meaning that
* threads blocked due to hitting the high watermark can wake up and continue
* to commit records.
*/
struct cv audit_watermark_cv;
/*
* Condition variable for auditing threads wait on when in fail-stop mode.
* Threads wait on this CV forever (and ever), never seeing the light of day
* again.
*/
static struct cv audit_fail_cv;
static ZONE_DEFINE(audit_record_zone, "audit_zone",
sizeof(struct kaudit_record), ZC_NONE);
/*
* Kernel audit information. This will store the current audit address
* or host information that the kernel will use when it's generating
* audit records. This data is modified by the A_GET{SET}KAUDIT auditon(2)
* command.
*/
static struct auditinfo_addr audit_kinfo;
static struct rwlock audit_kinfo_lock;
#define KINFO_LOCK_INIT() rw_init(&audit_kinfo_lock, \
"audit_kinfo_lock")
#define KINFO_RLOCK() rw_rlock(&audit_kinfo_lock)
#define KINFO_WLOCK() rw_wlock(&audit_kinfo_lock)
#define KINFO_RUNLOCK() rw_runlock(&audit_kinfo_lock)
#define KINFO_WUNLOCK() rw_wunlock(&audit_kinfo_lock)
void
audit_set_kinfo(struct auditinfo_addr *ak)
{
KASSERT(ak->ai_termid.at_type == AU_IPv4 ||
ak->ai_termid.at_type == AU_IPv6,
("audit_set_kinfo: invalid address type"));
KINFO_WLOCK();
bcopy(ak, &audit_kinfo, sizeof(audit_kinfo));
KINFO_WUNLOCK();
}
void
audit_get_kinfo(struct auditinfo_addr *ak)
{
KASSERT(audit_kinfo.ai_termid.at_type == AU_IPv4 ||
audit_kinfo.ai_termid.at_type == AU_IPv6,
("audit_set_kinfo: invalid address type"));
KINFO_RLOCK();
bcopy(&audit_kinfo, ak, sizeof(*ak));
KINFO_RUNLOCK();
}
/*
* Construct an audit record for the passed thread.
*/
static void
audit_record_ctor(proc_t p, struct kaudit_record *ar)
{
kauth_cred_t cred;
bzero(ar, sizeof(*ar));
ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC;
nanotime(&ar->k_ar.ar_starttime);
if (PROC_NULL != p) {
cred = kauth_cred_proc_ref(p);
/*
* Export the subject credential.
*/
cru2x(cred, &ar->k_ar.ar_subj_cred);
ar->k_ar.ar_subj_ruid = kauth_cred_getruid(cred);
ar->k_ar.ar_subj_rgid = kauth_cred_getrgid(cred);
ar->k_ar.ar_subj_egid = kauth_cred_getgid(cred);
ar->k_ar.ar_subj_pid = proc_getpid(p);
ar->k_ar.ar_subj_auid = cred->cr_audit.as_aia_p->ai_auid;
ar->k_ar.ar_subj_asid = cred->cr_audit.as_aia_p->ai_asid;
bcopy(&cred->cr_audit.as_mask, &ar->k_ar.ar_subj_amask,
sizeof(struct au_mask));
bcopy(&cred->cr_audit.as_aia_p->ai_termid,
&ar->k_ar.ar_subj_term_addr, sizeof(struct au_tid_addr));
kauth_cred_unref(&cred);
}
}
static void
audit_record_dtor(struct kaudit_record *ar)
{
if (ar->k_ar.ar_arg_upath1 != NULL) {
zfree(ZV_NAMEI, ar->k_ar.ar_arg_upath1);
}
if (ar->k_ar.ar_arg_upath2 != NULL) {
zfree(ZV_NAMEI, ar->k_ar.ar_arg_upath2);
}
if (ar->k_ar.ar_arg_kpath1 != NULL) {
zfree(ZV_NAMEI, ar->k_ar.ar_arg_kpath1);
}
if (ar->k_ar.ar_arg_kpath2 != NULL) {
zfree(ZV_NAMEI, ar->k_ar.ar_arg_kpath2);
}
if (ar->k_ar.ar_arg_text != NULL) {
zfree(ZV_NAMEI, ar->k_ar.ar_arg_text);
}
if (ar->k_ar.ar_arg_opaque != NULL) {
kfree_data(ar->k_ar.ar_arg_opaque, ar->k_ar.ar_arg_opq_size);
}
if (ar->k_ar.ar_arg_data != NULL) {
kfree_data_addr(ar->k_ar.ar_arg_data);
}
if (ar->k_udata != NULL) {
kfree_data_addr(ar->k_udata);
}
if (ar->k_ar.ar_arg_argv != NULL) {
kfree_data_addr(ar->k_ar.ar_arg_argv);
}
if (ar->k_ar.ar_arg_envv != NULL) {
kfree_data_addr(ar->k_ar.ar_arg_envv);
}
audit_identity_info_destruct(&ar->k_ar.ar_arg_identity);
}
/*
* Initialize the Audit subsystem: configuration state, work queue,
* synchronization primitives, worker thread, and trigger device node. Also
* call into the BSM assembly code to initialize it.
*/
void
audit_init(void)
{
audit_enabled = 0;
audit_syscalls = 0;
audit_kevent_mask = 0;
audit_suspended = 0;
audit_panic_on_write_fail = 0;
audit_fail_stop = 0;
audit_in_failure = 0;
audit_argv = 0;
audit_arge = 0;
audit_ctl_mode = AUDIT_CTLMODE_NORMAL;
audit_expire_after.age = 0;
audit_expire_after.size = 0;
audit_expire_after.op_type = AUDIT_EXPIRE_OP_AND;
audit_fstat.af_filesz = 0; /* '0' means unset, unbounded. */
audit_fstat.af_currsz = 0;
audit_nae_mask.am_success = 0;
audit_nae_mask.am_failure = 0;
TAILQ_INIT(&audit_q);
audit_q_len = 0;
audit_pre_q_len = 0;
audit_qctrl.aq_hiwater = AQ_HIWATER;
audit_qctrl.aq_lowater = AQ_LOWATER;
audit_qctrl.aq_bufsz = AQ_BUFSZ;
audit_qctrl.aq_minfree = AU_FS_MINFREE;
audit_kinfo.ai_termid.at_type = AU_IPv4;
audit_kinfo.ai_termid.at_addr[0] = INADDR_ANY;
mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF);
KINFO_LOCK_INIT();
cv_init(&audit_worker_cv, "audit_worker_cv");
cv_init(&audit_drain_cv, "audit_drain_cv");
cv_init(&audit_watermark_cv, "audit_watermark_cv");
cv_init(&audit_fail_cv, "audit_fail_cv");
/* Init audit session subsystem. */
audit_session_init();
/* Initialize the BSM audit subsystem. */
kau_init();
/* audit_trigger_init(); */
/* Start audit worker thread. */
(void) audit_pipe_init();
/* Start audit worker thread. */
audit_worker_init();
}
/*
* Drain the audit queue and close the log at shutdown. Note that this can
* be called both from the system shutdown path and also from audit
* configuration syscalls, so 'arg' and 'howto' are ignored.
*/
void
audit_shutdown(void)
{
audit_rotate_vnode(NULL, NULL);
}
/*
* Return the current thread's audit record, if any.
*/
struct kaudit_record *
currecord(void)
{
return curthread()->uu_ar;
}
/*
* XXXAUDIT: There are a number of races present in the code below due to
* release and re-grab of the mutex. The code should be revised to become
* slightly less racy.
*
* XXXAUDIT: Shouldn't there be logic here to sleep waiting on available
* pre_q space, suspending the system call until there is room?
*/
struct kaudit_record *
audit_new(int event, proc_t p, __unused struct uthread *uthread)
{
struct kaudit_record *ar;
int no_record;
int audit_override;
/*
* Override the audit_suspended and audit_enabled if it always
* audits session events.
*
* XXXss - This really needs to be a generalized call to a filter
* interface so if other things that use the audit subsystem in the
* future can simply plugged in.
*/
audit_override = (AUE_SESSION_START == event ||
AUE_SESSION_UPDATE == event || AUE_SESSION_END == event ||
AUE_SESSION_CLOSE == event);
mtx_lock(&audit_mtx);
no_record = (audit_suspended || !audit_enabled);
mtx_unlock(&audit_mtx);
if (!audit_override && no_record) {
return NULL;
}
/*
* Initialize the audit record header.
* XXX: We may want to fail-stop if allocation fails.
*
* Note: the number of outstanding uncommitted audit records is
* limited to the number of concurrent threads servicing system calls
* in the kernel.
*/
ar = zalloc_flags(audit_record_zone, Z_WAITOK | Z_NOFAIL);
audit_record_ctor(p, ar);
ar->k_ar.ar_event = event;
#if CONFIG_MACF
if (PROC_NULL != p) {
if (audit_mac_new(p, ar) != 0) {
zfree(audit_record_zone, ar);
return NULL;
}
} else {
ar->k_ar.ar_mac_records = NULL;
}
#endif
mtx_lock(&audit_mtx);
audit_pre_q_len++;
mtx_unlock(&audit_mtx);
return ar;
}
void
audit_free(struct kaudit_record *ar)
{
audit_record_dtor(ar);
#if CONFIG_MACF
if (NULL != ar->k_ar.ar_mac_records) {
audit_mac_free(ar);
}
#endif
zfree(audit_record_zone, ar);
}
void
audit_commit(struct kaudit_record *ar, int error, int retval)
{
au_event_t event;
au_class_t class;
au_id_t auid;
int sorf;
struct au_mask *aumask;
int audit_override;
if (ar == NULL) {
return;
}
/*
* Decide whether to commit the audit record by checking the error
* value from the system call and using the appropriate audit mask.
*/
if (ar->k_ar.ar_subj_auid == AU_DEFAUDITID) {
aumask = &audit_nae_mask;
} else {
aumask = &ar->k_ar.ar_subj_amask;
}
if (error) {
sorf = AU_PRS_FAILURE;
} else {
sorf = AU_PRS_SUCCESS;
}
switch (ar->k_ar.ar_event) {
case AUE_OPEN_RWTC:
/*
* The open syscall always writes a AUE_OPEN_RWTC event;
* change it to the proper type of event based on the flags
* and the error value.
*/
ar->k_ar.ar_event = audit_flags_and_error_to_openevent(
ar->k_ar.ar_arg_fflags, error);
break;
case AUE_OPEN_EXTENDED_RWTC:
/*
* The open_extended syscall always writes a
* AUE_OPEN_EXTENDEDRWTC event; change it to the proper type of
* event based on the flags and the error value.
*/
ar->k_ar.ar_event = audit_flags_and_error_to_openextendedevent(
ar->k_ar.ar_arg_fflags, error);
break;
case AUE_OPENAT_RWTC:
/*
* The openat syscall always writes a
* AUE_OPENAT_RWTC event; change it to the proper type of
* event based on the flags and the error value.
*/
ar->k_ar.ar_event = audit_flags_and_error_to_openatevent(
ar->k_ar.ar_arg_fflags, error);
break;
case AUE_OPENBYID_RWT:
/*
* The openbyid syscall always writes a
* AUE_OPENBYID_RWT event; change it to the proper type of
* event based on the flags and the error value.
*/
ar->k_ar.ar_event = audit_flags_and_error_to_openbyidevent(
ar->k_ar.ar_arg_fflags, error);
break;
case AUE_SYSCTL:
ar->k_ar.ar_event = audit_ctlname_to_sysctlevent(
ar->k_ar.ar_arg_ctlname, ar->k_ar.ar_valid_arg);
break;
case AUE_AUDITON:
/* Convert the auditon() command to an event. */
ar->k_ar.ar_event = auditon_command_event(ar->k_ar.ar_arg_cmd);
break;
case AUE_FCNTL:
/* Convert some fcntl() commands to their own events. */
ar->k_ar.ar_event = audit_fcntl_command_event(
ar->k_ar.ar_arg_cmd, ar->k_ar.ar_arg_fflags, error);
break;
}
auid = ar->k_ar.ar_subj_auid;
event = ar->k_ar.ar_event;
class = au_event_class(event);
/*
* See if we need to override the audit_suspend and audit_enabled
* flags.
*
* XXXss - This check needs to be generalized so new filters can
* easily be added.
*/
audit_override = (AUE_SESSION_START == event ||
AUE_SESSION_UPDATE == event || AUE_SESSION_END == event ||
AUE_SESSION_CLOSE == event);
ar->k_ar_commit |= AR_COMMIT_KERNEL;
if (au_preselect(event, class, aumask, sorf) != 0) {
ar->k_ar_commit |= AR_PRESELECT_TRAIL;
}
if (audit_pipe_preselect(auid, event, class, sorf,
ar->k_ar_commit & AR_PRESELECT_TRAIL) != 0) {
ar->k_ar_commit |= AR_PRESELECT_PIPE;
}
if ((ar->k_ar_commit & (AR_PRESELECT_TRAIL | AR_PRESELECT_PIPE |
AR_PRESELECT_USER_TRAIL | AR_PRESELECT_USER_PIPE |
AR_PRESELECT_FILTER)) == 0) {
mtx_lock(&audit_mtx);
audit_pre_q_len--;
mtx_unlock(&audit_mtx);
audit_free(ar);
return;
}
ar->k_ar.ar_errno = error;
ar->k_ar.ar_retval = retval;
nanotime(&ar->k_ar.ar_endtime);
/*
* Note: it could be that some records initiated while audit was
* enabled should still be committed?
*/
mtx_lock(&audit_mtx);
if (!audit_override && (audit_suspended || !audit_enabled)) {
audit_pre_q_len--;
mtx_unlock(&audit_mtx);
audit_free(ar);
return;
}
/*
* Constrain the number of committed audit records based on the
* configurable parameter.
*/
while (audit_q_len >= audit_qctrl.aq_hiwater) {
cv_wait(&audit_watermark_cv, &audit_mtx);
}
TAILQ_INSERT_TAIL(&audit_q, ar, k_q);
audit_q_len++;
audit_pre_q_len--;
cv_signal(&audit_worker_cv);
mtx_unlock(&audit_mtx);
}
/*
* audit_syscall_enter() is called on entry to each system call. It is
* responsible for deciding whether or not to audit the call (preselection),
* and if so, allocating a per-thread audit record. audit_new() will fill in
* basic thread/credential properties.
*/
void
audit_syscall_enter(unsigned int code, proc_t proc, struct uthread *uthread)
{
struct au_mask *aumask;
au_class_t class;
au_event_t event;
au_id_t auid;
kauth_cred_t cred;
/*
* In FreeBSD, each ABI has its own system call table, and hence
* mapping of system call codes to audit events. Convert the code to
* an audit event identifier using the process system call table
* reference. In Darwin, there's only one, so we use the global
* symbol for the system call table. No audit record is generated
* for bad system calls, as no operation has been performed.
*
* In Mac OS X, the audit events are stored in a table seperate from
* the syscall table(s). This table is generated by makesyscalls.sh
* from syscalls.master and stored in audit_kevents.c.
*/
if (code >= nsysent) {
return;
}
event = sys_au_event[code];
if (event == AUE_NULL) {
return;
}
KASSERT(uthread->uu_ar == NULL,
("audit_syscall_enter: uthread->uu_ar != NULL"));
/*
* Check which audit mask to use; either the kernel non-attributable
* event mask or the process audit mask.
*/
cred = kauth_cred_proc_ref(proc);
auid = cred->cr_audit.as_aia_p->ai_auid;
if (auid == AU_DEFAUDITID) {
aumask = &audit_nae_mask;
} else {
aumask = &cred->cr_audit.as_mask;
}
/*
* Allocate an audit record, if preselection allows it, and store in
* the thread for later use.
*/
class = au_event_class(event);
#if CONFIG_MACF
/*
* Note: audit_mac_syscall_enter() may call audit_new() and allocate
* memory for the audit record (uu_ar).
*/
if (audit_mac_syscall_enter(code, proc, uthread, cred, event) == 0) {
goto out;
}
#endif
if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
/*
* If we're out of space and need to suspend unprivileged
* processes, do that here rather than trying to allocate
* another audit record.
*
* Note: we might wish to be able to continue here in the
* future, if the system recovers. That should be possible
* by means of checking the condition in a loop around
* cv_wait(). It might be desirable to reevaluate whether an
* audit record is still required for this event by
* re-calling au_preselect().
*/
if (audit_in_failure &&
suser(cred, &proc->p_acflag) != 0) {
cv_wait(&audit_fail_cv, &audit_mtx);
panic("audit_failing_stop: thread continued");
}
if (uthread->uu_ar == NULL) {
uthread->uu_ar = audit_new(event, proc, uthread);
}
} else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
if (uthread->uu_ar == NULL) {
uthread->uu_ar = audit_new(event, proc, uthread);
}
}
/*
* All audited events will contain an identity
*
* Note: Identity should be obtained prior to the syscall implementation
* being called to handle cases like execve(2) where the process changes
*/
AUDIT_ARG(identity);
out:
kauth_cred_unref(&cred);
}
/*
* audit_syscall_exit() is called from the return of every system call, or in
* the event of exit1(), during the execution of exit1(). It is responsible
* for committing the audit record, if any, along with return condition.
*
* Note: The audit_syscall_exit() parameter list was modified to support
* mac_audit_check_postselect(), which requires the syscall number.
*/
#if CONFIG_MACF
void
audit_syscall_exit(unsigned int code, int error, __unused proc_t proc,
struct uthread *uthread)
#else
void
audit_syscall_exit(int error, __unsed proc_t proc, struct uthread *uthread)
#endif
{
int retval;
/*
* Commit the audit record as desired; once we pass the record into
* audit_commit(), the memory is owned by the audit subsystem. The
* return value from the system call is stored on the user thread.
* If there was an error, the return value is set to -1, imitating
* the behavior of the cerror routine.
*/
if (error) {
retval = -1;
} else {
retval = uthread->uu_rval[0];
}
#if CONFIG_MACF
if (audit_mac_syscall_exit(code, uthread, error, retval) != 0) {
goto out;
}
#endif
audit_commit(uthread->uu_ar, error, retval);
out:
uthread->uu_ar = NULL;
}
/*
* For system calls such as posix_spawn(2) the sub operations (i.e., file actions
* and port actions) need to be audited as their own events. Like with system
* calls we need to determine if the sub operation needs to be audited by
* examining preselection masks.
*/
void
audit_subcall_enter(au_event_t event, proc_t proc, struct uthread *uthread)
{
struct au_mask *aumask;
au_class_t class;
au_id_t auid;
kauth_cred_t cred;
/*
* Check which audit mask to use; either the kernel non-attributable
* event mask or the process audit mask.
*/
cred = kauth_cred_proc_ref(proc);
auid = cred->cr_audit.as_aia_p->ai_auid;
if (auid == AU_DEFAUDITID) {
aumask = &audit_nae_mask;
} else {
aumask = &cred->cr_audit.as_mask;
}
/*
* Allocate an audit record, if preselection allows it, and store in
* the thread for later use.
*/
class = au_event_class(event);
if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
/*
* If we're out of space and need to suspend unprivileged
* processes, do that here rather than trying to allocate
* another audit record.
*
* Note: we might wish to be able to continue here in the
* future, if the system recovers. That should be possible
* by means of checking the condition in a loop around
* cv_wait(). It might be desirable to reevaluate whether an
* audit record is still required for this event by
* re-calling au_preselect().
*/
if (audit_in_failure &&
suser(cred, &proc->p_acflag) != 0) {
cv_wait(&audit_fail_cv, &audit_mtx);
panic("audit_failing_stop: thread continued");
}
if (uthread->uu_ar == NULL) {
uthread->uu_ar = audit_new(event, proc, uthread);
}
} else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
if (uthread->uu_ar == NULL) {
uthread->uu_ar = audit_new(event, proc, uthread);
}
}
kauth_cred_unref(&cred);
}
void
audit_subcall_exit(int error, struct uthread *uthread)
{
/* A subcall doesn't have a return value so always zero. */
audit_commit(uthread->uu_ar, error, 0 /* retval */);
uthread->uu_ar = NULL;
}
/*
* Calls to set up and tear down audit structures used during Mach system
* calls.
*/
void
audit_mach_syscall_enter(unsigned short event)
{
struct uthread *uthread;
proc_t proc;
struct au_mask *aumask;
kauth_cred_t cred;
au_class_t class;
au_id_t auid;
if (event == AUE_NULL) {
return;
}
uthread = curthread();
if (uthread == NULL) {
return;
}
proc = current_proc();
if (proc == NULL) {
return;
}
KASSERT(uthread->uu_ar == NULL,
("audit_mach_syscall_enter: uthread->uu_ar != NULL"));
cred = kauth_cred_proc_ref(proc);
auid = cred->cr_audit.as_aia_p->ai_auid;
/*
* Check which audit mask to use; either the kernel non-attributable
* event mask or the process audit mask.
*/
if (auid == AU_DEFAUDITID) {
aumask = &audit_nae_mask;
} else {
aumask = &cred->cr_audit.as_mask;
}
/*
* Allocate an audit record, if desired, and store in the BSD thread
* for later use.
*/
class = au_event_class(event);
if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
uthread->uu_ar = audit_new(event, proc, uthread);
} else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
uthread->uu_ar = audit_new(event, proc, uthread);
} else {
uthread->uu_ar = NULL;
}
kauth_cred_unref(&cred);
}
void
audit_mach_syscall_exit(int retval, struct uthread *uthread)
{
/*
* The error code from Mach system calls is the same as the
* return value
*/
/* XXX Is the above statement always true? */
audit_commit(uthread->uu_ar, retval, retval);
uthread->uu_ar = NULL;
}
/*
* kau_will_audit can be used by a security policy to determine
* if an audit record will be stored, reducing wasted memory allocation
* and string handling.
*/
int
kau_will_audit(void)
{
return audit_enabled && currecord() != NULL;
}
#if CONFIG_COREDUMP
void
audit_proc_coredump(proc_t proc, const char *path, int errcode)
{
struct kaudit_record *ar;
struct au_mask *aumask;
au_class_t class;
int ret, sorf;
char **pathp;
au_id_t auid;
kauth_cred_t my_cred;
struct uthread *uthread;
ret = 0;
/*
* Make sure we are using the correct preselection mask.
*/
my_cred = kauth_cred_proc_ref(proc);
auid = my_cred->cr_audit.as_aia_p->ai_auid;
if (auid == AU_DEFAUDITID) {
aumask = &audit_nae_mask;
} else {
aumask = &my_cred->cr_audit.as_mask;
}
kauth_cred_unref(&my_cred);
/*
* It's possible for coredump(9) generation to fail. Make sure that
* we handle this case correctly for preselection.
*/
if (errcode != 0) {
sorf = AU_PRS_FAILURE;
} else {
sorf = AU_PRS_SUCCESS;
}
class = au_event_class(AUE_CORE);
if (au_preselect(AUE_CORE, class, aumask, sorf) == 0 &&
audit_pipe_preselect(auid, AUE_CORE, class, sorf, 0) == 0) {
return;
}
/*
* If we are interested in seeing this audit record, allocate it.
* Where possible coredump records should contain a pathname and arg32
* (signal) tokens.
*/
uthread = curthread();
ar = audit_new(AUE_CORE, proc, uthread);
if (ar == NULL) {
return;
}
if (path != NULL) {
pathp = &ar->k_ar.ar_arg_upath1;
*pathp = zalloc(ZV_NAMEI);
if (audit_canon_path(vfs_context_cwd(vfs_context_current()), path,
*pathp)) {
zfree(ZV_NAMEI, *pathp);
} else {
ARG_SET_VALID(ar, ARG_UPATH1);
}
}
ar->k_ar.ar_arg_signum = proc->p_sigacts.ps_sig;
ARG_SET_VALID(ar, ARG_SIGNUM);
if (errcode != 0) {
ret = 1;
}
audit_commit(ar, errcode, ret);
}
#endif /* CONFIG_COREDUMP */
#endif /* CONFIG_AUDIT */