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/*-
* Copyright (c) 2006 Robert N. M. Watson
* Copyright (c) 2008-2009 Apple, Inc.
* All rights reserved.
*
* This software was developed by Robert Watson for the TrustedBSD Project.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND 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 THE AUTHOR OR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/security/audit/audit_pipe.c 225177 2011-08-25 15:51:54Z attilio $");
#include <sys/param.h>
#include <sys/condvar.h>
#include <sys/conf.h>
#include <sys/eventhandler.h>
#include <sys/filio.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/rwlock.h>
#include <sys/selinfo.h>
#include <sys/sigio.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/sx.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <security/audit/audit.h>
#include <security/audit/audit_ioctl.h>
#include <security/audit/audit_private.h>
/*
* Implementation of a clonable special device providing a live stream of BSM
* audit data. Consumers receive a "tee" of the system audit trail by
* default, but may also define alternative event selections using ioctls.
* This interface provides unreliable but timely access to audit events.
* Consumers should be very careful to avoid introducing event cycles.
*/
/*
* Memory types.
*/
static MALLOC_DEFINE(M_AUDIT_PIPE, "audit_pipe", "Audit pipes");
static MALLOC_DEFINE(M_AUDIT_PIPE_ENTRY, "audit_pipeent",
"Audit pipe entries and buffers");
static MALLOC_DEFINE(M_AUDIT_PIPE_PRESELECT, "audit_pipe_presel",
"Audit pipe preselection structure");
/*
* Audit pipe buffer parameters.
*/
#define AUDIT_PIPE_QLIMIT_DEFAULT (128)
#define AUDIT_PIPE_QLIMIT_MIN (1)
#define AUDIT_PIPE_QLIMIT_MAX (1024)
/*
* Description of an entry in an audit_pipe.
*/
struct audit_pipe_entry {
void *ape_record;
u_int ape_record_len;
TAILQ_ENTRY(audit_pipe_entry) ape_queue;
};
/*
* Audit pipes allow processes to express "interest" in the set of records
* that are delivered via the pipe. They do this in a similar manner to the
* mechanism for audit trail configuration, by expressing two global masks,
* and optionally expressing per-auid masks. The following data structure is
* the per-auid mask description. The global state is stored in the audit
* pipe data structure.
*
* We may want to consider a more space/time-efficient data structure once
* usage patterns for per-auid specifications are clear.
*/
struct audit_pipe_preselect {
au_id_t app_auid;
au_mask_t app_mask;
TAILQ_ENTRY(audit_pipe_preselect) app_list;
};
/*
* Description of an individual audit_pipe. Consists largely of a bounded
* length queue.
*/
#define AUDIT_PIPE_ASYNC 0x00000001
#define AUDIT_PIPE_NBIO 0x00000002
struct audit_pipe {
int ap_open; /* Device open? */
u_int ap_flags;
struct selinfo ap_selinfo;
struct sigio *ap_sigio;
/*
* Per-pipe mutex protecting most fields in this data structure.
*/
struct mtx ap_mtx;
/*
* Per-pipe sleep lock serializing user-generated reads and flushes.
* uiomove() is called to copy out the current head record's data
* while the record remains in the queue, so we prevent other threads
* from removing it using this lock.
*/
struct sx ap_sx;
/*
* Condition variable to signal when data has been delivered to a
* pipe.
*/
struct cv ap_cv;
/*
* Various queue-reated variables: qlen and qlimit are a count of
* records in the queue; qbyteslen is the number of bytes of data
* across all records, and qoffset is the amount read so far of the
* first record in the queue. The number of bytes available for
* reading in the queue is qbyteslen - qoffset.
*/
u_int ap_qlen;
u_int ap_qlimit;
u_int ap_qbyteslen;
u_int ap_qoffset;
/*
* Per-pipe operation statistics.
*/
u_int64_t ap_inserts; /* Records added. */
u_int64_t ap_reads; /* Records read. */
u_int64_t ap_drops; /* Records dropped. */
/*
* Fields relating to pipe interest: global masks for unmatched
* processes (attributable, non-attributable), and a list of specific
* interest specifications by auid.
*/
int ap_preselect_mode;
au_mask_t ap_preselect_flags;
au_mask_t ap_preselect_naflags;
TAILQ_HEAD(, audit_pipe_preselect) ap_preselect_list;
/*
* Current pending record list. Protected by a combination of ap_mtx
* and ap_sx. Note particularly that *both* locks are required to
* remove a record from the head of the queue, as an in-progress read
* may sleep while copying and therefore cannot hold ap_mtx.
*/
TAILQ_HEAD(, audit_pipe_entry) ap_queue;
/*
* Global pipe list.
*/
TAILQ_ENTRY(audit_pipe) ap_list;
};
#define AUDIT_PIPE_LOCK(ap) mtx_lock(&(ap)->ap_mtx)
#define AUDIT_PIPE_LOCK_ASSERT(ap) mtx_assert(&(ap)->ap_mtx, MA_OWNED)
#define AUDIT_PIPE_LOCK_DESTROY(ap) mtx_destroy(&(ap)->ap_mtx)
#define AUDIT_PIPE_LOCK_INIT(ap) mtx_init(&(ap)->ap_mtx, \
"audit_pipe_mtx", NULL, MTX_DEF)
#define AUDIT_PIPE_UNLOCK(ap) mtx_unlock(&(ap)->ap_mtx)
#define AUDIT_PIPE_MTX(ap) (&(ap)->ap_mtx)
#define AUDIT_PIPE_SX_LOCK_DESTROY(ap) sx_destroy(&(ap)->ap_sx)
#define AUDIT_PIPE_SX_LOCK_INIT(ap) sx_init(&(ap)->ap_sx, "audit_pipe_sx")
#define AUDIT_PIPE_SX_XLOCK_ASSERT(ap) sx_assert(&(ap)->ap_sx, SA_XLOCKED)
#define AUDIT_PIPE_SX_XLOCK_SIG(ap) sx_xlock_sig(&(ap)->ap_sx)
#define AUDIT_PIPE_SX_XUNLOCK(ap) sx_xunlock(&(ap)->ap_sx)
/*
* Global list of audit pipes, rwlock to protect it. Individual record
* queues on pipes are protected by per-pipe locks; these locks synchronize
* between threads walking the list to deliver to individual pipes and add/
* remove of pipes, and are mostly acquired for read.
*/
static TAILQ_HEAD(, audit_pipe) audit_pipe_list;
static struct rwlock audit_pipe_lock;
#define AUDIT_PIPE_LIST_LOCK_INIT() rw_init(&audit_pipe_lock, \
"audit_pipe_list_lock")
#define AUDIT_PIPE_LIST_RLOCK() rw_rlock(&audit_pipe_lock)
#define AUDIT_PIPE_LIST_RUNLOCK() rw_runlock(&audit_pipe_lock)
#define AUDIT_PIPE_LIST_WLOCK() rw_wlock(&audit_pipe_lock)
#define AUDIT_PIPE_LIST_WLOCK_ASSERT() rw_assert(&audit_pipe_lock, \
RA_WLOCKED)
#define AUDIT_PIPE_LIST_WUNLOCK() rw_wunlock(&audit_pipe_lock)
/*
* Cloning related variables and constants.
*/
#define AUDIT_PIPE_NAME "auditpipe"
static eventhandler_tag audit_pipe_eh_tag;
static struct clonedevs *audit_pipe_clones;
/*
* Special device methods and definition.
*/
static d_open_t audit_pipe_open;
static d_close_t audit_pipe_close;
static d_read_t audit_pipe_read;
static d_ioctl_t audit_pipe_ioctl;
static d_poll_t audit_pipe_poll;
static d_kqfilter_t audit_pipe_kqfilter;
static struct cdevsw audit_pipe_cdevsw = {
.d_version = D_VERSION,
.d_flags = D_PSEUDO | D_NEEDMINOR,
.d_open = audit_pipe_open,
.d_close = audit_pipe_close,
.d_read = audit_pipe_read,
.d_ioctl = audit_pipe_ioctl,
.d_poll = audit_pipe_poll,
.d_kqfilter = audit_pipe_kqfilter,
.d_name = AUDIT_PIPE_NAME,
};
static int audit_pipe_kqread(struct knote *note, long hint);
static void audit_pipe_kqdetach(struct knote *note);
static struct filterops audit_pipe_read_filterops = {
.f_isfd = 1,
.f_attach = NULL,
.f_detach = audit_pipe_kqdetach,
.f_event = audit_pipe_kqread,
};
/*
* Some global statistics on audit pipes.
*/
static int audit_pipe_count; /* Current number of pipes. */
static u_int64_t audit_pipe_ever; /* Pipes ever allocated. */
static u_int64_t audit_pipe_records; /* Records seen. */
static u_int64_t audit_pipe_drops; /* Global record drop count. */
/*
* Free an audit pipe entry.
*/
static void
audit_pipe_entry_free(struct audit_pipe_entry *ape)
{
free(ape->ape_record, M_AUDIT_PIPE_ENTRY);
free(ape, M_AUDIT_PIPE_ENTRY);
}
/*
* Find an audit pipe preselection specification for an auid, if any.
*/
static struct audit_pipe_preselect *
audit_pipe_preselect_find(struct audit_pipe *ap, au_id_t auid)
{
struct audit_pipe_preselect *app;
AUDIT_PIPE_LOCK_ASSERT(ap);
TAILQ_FOREACH(app, &ap->ap_preselect_list, app_list) {
if (app->app_auid == auid)
return (app);
}
return (NULL);
}
/*
* Query the per-pipe mask for a specific auid.
*/
static int
audit_pipe_preselect_get(struct audit_pipe *ap, au_id_t auid,
au_mask_t *maskp)
{
struct audit_pipe_preselect *app;
int error;
AUDIT_PIPE_LOCK(ap);
app = audit_pipe_preselect_find(ap, auid);
if (app != NULL) {
*maskp = app->app_mask;
error = 0;
} else
error = ENOENT;
AUDIT_PIPE_UNLOCK(ap);
return (error);
}
/*
* Set the per-pipe mask for a specific auid. Add a new entry if needed;
* otherwise, update the current entry.
*/
static void
audit_pipe_preselect_set(struct audit_pipe *ap, au_id_t auid, au_mask_t mask)
{
struct audit_pipe_preselect *app, *app_new;
/*
* Pessimistically assume that the auid doesn't already have a mask
* set, and allocate. We will free it if it is unneeded.
*/
app_new = malloc(sizeof(*app_new), M_AUDIT_PIPE_PRESELECT, M_WAITOK);
AUDIT_PIPE_LOCK(ap);
app = audit_pipe_preselect_find(ap, auid);
if (app == NULL) {
app = app_new;
app_new = NULL;
app->app_auid = auid;
TAILQ_INSERT_TAIL(&ap->ap_preselect_list, app, app_list);
}
app->app_mask = mask;
AUDIT_PIPE_UNLOCK(ap);
if (app_new != NULL)
free(app_new, M_AUDIT_PIPE_PRESELECT);
}
/*
* Delete a per-auid mask on an audit pipe.
*/
static int
audit_pipe_preselect_delete(struct audit_pipe *ap, au_id_t auid)
{
struct audit_pipe_preselect *app;
int error;
AUDIT_PIPE_LOCK(ap);
app = audit_pipe_preselect_find(ap, auid);
if (app != NULL) {
TAILQ_REMOVE(&ap->ap_preselect_list, app, app_list);
error = 0;
} else
error = ENOENT;
AUDIT_PIPE_UNLOCK(ap);
if (app != NULL)
free(app, M_AUDIT_PIPE_PRESELECT);
return (error);
}
/*
* Delete all per-auid masks on an audit pipe.
*/
static void
audit_pipe_preselect_flush_locked(struct audit_pipe *ap)
{
struct audit_pipe_preselect *app;
AUDIT_PIPE_LOCK_ASSERT(ap);
while ((app = TAILQ_FIRST(&ap->ap_preselect_list)) != NULL) {
TAILQ_REMOVE(&ap->ap_preselect_list, app, app_list);
free(app, M_AUDIT_PIPE_PRESELECT);
}
}
static void
audit_pipe_preselect_flush(struct audit_pipe *ap)
{
AUDIT_PIPE_LOCK(ap);
audit_pipe_preselect_flush_locked(ap);
AUDIT_PIPE_UNLOCK(ap);
}
/*-
* Determine whether a specific audit pipe matches a record with these
* properties. Algorithm is as follows:
*
* - If the pipe is configured to track the default trail configuration, then
* use the results of global preselection matching.
* - If not, search for a specifically configured auid entry matching the
* event. If an entry is found, use that.
* - Otherwise, use the default flags or naflags configured for the pipe.
*/
static int
audit_pipe_preselect_check(struct audit_pipe *ap, au_id_t auid,
au_event_t event, au_class_t class, int sorf, int trail_preselect)
{
struct audit_pipe_preselect *app;
AUDIT_PIPE_LOCK_ASSERT(ap);
switch (ap->ap_preselect_mode) {
case AUDITPIPE_PRESELECT_MODE_TRAIL:
return (trail_preselect);
case AUDITPIPE_PRESELECT_MODE_LOCAL:
app = audit_pipe_preselect_find(ap, auid);
if (app == NULL) {
if (auid == AU_DEFAUDITID)
return (au_preselect(event, class,
&ap->ap_preselect_naflags, sorf));
else
return (au_preselect(event, class,
&ap->ap_preselect_flags, sorf));
} else
return (au_preselect(event, class, &app->app_mask,
sorf));
default:
panic("audit_pipe_preselect_check: mode %d",
ap->ap_preselect_mode);
}
return (0);
}
/*
* Determine whether there exists a pipe interested in a record with specific
* properties.
*/
int
audit_pipe_preselect(au_id_t auid, au_event_t event, au_class_t class,
int sorf, int trail_preselect)
{
struct audit_pipe *ap;
/* Lockless read to avoid acquiring the global lock if not needed. */
if (TAILQ_EMPTY(&audit_pipe_list))
return (0);
AUDIT_PIPE_LIST_RLOCK();
TAILQ_FOREACH(ap, &audit_pipe_list, ap_list) {
AUDIT_PIPE_LOCK(ap);
if (audit_pipe_preselect_check(ap, auid, event, class, sorf,
trail_preselect)) {
AUDIT_PIPE_UNLOCK(ap);
AUDIT_PIPE_LIST_RUNLOCK();
return (1);
}
AUDIT_PIPE_UNLOCK(ap);
}
AUDIT_PIPE_LIST_RUNLOCK();
return (0);
}
/*
* Append individual record to a queue -- allocate queue-local buffer, and
* add to the queue. If the queue is full or we can't allocate memory, drop
* the newest record.
*/
static void
audit_pipe_append(struct audit_pipe *ap, void *record, u_int record_len)
{
struct audit_pipe_entry *ape;
AUDIT_PIPE_LOCK_ASSERT(ap);
if (ap->ap_qlen >= ap->ap_qlimit) {
ap->ap_drops++;
audit_pipe_drops++;
return;
}
ape = malloc(sizeof(*ape), M_AUDIT_PIPE_ENTRY, M_NOWAIT | M_ZERO);
if (ape == NULL) {
ap->ap_drops++;
audit_pipe_drops++;
return;
}
ape->ape_record = malloc(record_len, M_AUDIT_PIPE_ENTRY, M_NOWAIT);
if (ape->ape_record == NULL) {
free(ape, M_AUDIT_PIPE_ENTRY);
ap->ap_drops++;
audit_pipe_drops++;
return;
}
bcopy(record, ape->ape_record, record_len);
ape->ape_record_len = record_len;
TAILQ_INSERT_TAIL(&ap->ap_queue, ape, ape_queue);
ap->ap_inserts++;
ap->ap_qlen++;
ap->ap_qbyteslen += ape->ape_record_len;
selwakeuppri(&ap->ap_selinfo, PSOCK);
KNOTE_LOCKED(&ap->ap_selinfo.si_note, 0);
if (ap->ap_flags & AUDIT_PIPE_ASYNC)
pgsigio(&ap->ap_sigio, SIGIO, 0);
cv_broadcast(&ap->ap_cv);
}
/*
* audit_pipe_submit(): audit_worker submits audit records via this
* interface, which arranges for them to be delivered to pipe queues.
*/
void
audit_pipe_submit(au_id_t auid, au_event_t event, au_class_t class, int sorf,
int trail_select, void *record, u_int record_len)
{
struct audit_pipe *ap;
/*
* Lockless read to avoid lock overhead if pipes are not in use.
*/
if (TAILQ_FIRST(&audit_pipe_list) == NULL)
return;
AUDIT_PIPE_LIST_RLOCK();
TAILQ_FOREACH(ap, &audit_pipe_list, ap_list) {
AUDIT_PIPE_LOCK(ap);
if (audit_pipe_preselect_check(ap, auid, event, class, sorf,
trail_select))
audit_pipe_append(ap, record, record_len);
AUDIT_PIPE_UNLOCK(ap);
}
AUDIT_PIPE_LIST_RUNLOCK();
/* Unlocked increment. */
audit_pipe_records++;
}
/*
* audit_pipe_submit_user(): the same as audit_pipe_submit(), except that
* since we don't currently have selection information available, it is
* delivered to the pipe unconditionally.
*
* XXXRW: This is a bug. The BSM check routine for submitting a user record
* should parse that information and return it.
*/
void
audit_pipe_submit_user(void *record, u_int record_len)
{
struct audit_pipe *ap;
/*
* Lockless read to avoid lock overhead if pipes are not in use.
*/
if (TAILQ_FIRST(&audit_pipe_list) == NULL)
return;
AUDIT_PIPE_LIST_RLOCK();
TAILQ_FOREACH(ap, &audit_pipe_list, ap_list) {
AUDIT_PIPE_LOCK(ap);
audit_pipe_append(ap, record, record_len);
AUDIT_PIPE_UNLOCK(ap);
}
AUDIT_PIPE_LIST_RUNLOCK();
/* Unlocked increment. */
audit_pipe_records++;
}
/*
* Allocate a new audit pipe. Connects the pipe, on success, to the global
* list and updates statistics.
*/
static struct audit_pipe *
audit_pipe_alloc(void)
{
struct audit_pipe *ap;
AUDIT_PIPE_LIST_WLOCK_ASSERT();
ap = malloc(sizeof(*ap), M_AUDIT_PIPE, M_NOWAIT | M_ZERO);
if (ap == NULL)
return (NULL);
ap->ap_qlimit = AUDIT_PIPE_QLIMIT_DEFAULT;
TAILQ_INIT(&ap->ap_queue);
knlist_init_mtx(&ap->ap_selinfo.si_note, AUDIT_PIPE_MTX(ap));
AUDIT_PIPE_LOCK_INIT(ap);
AUDIT_PIPE_SX_LOCK_INIT(ap);
cv_init(&ap->ap_cv, "audit_pipe");
/*
* Default flags, naflags, and auid-specific preselection settings to
* 0. Initialize the mode to the global trail so that if praudit(1)
* is run on /dev/auditpipe, it sees events associated with the
* default trail. Pipe-aware application can clear the flag, set
* custom masks, and flush the pipe as needed.
*/
bzero(&ap->ap_preselect_flags, sizeof(ap->ap_preselect_flags));
bzero(&ap->ap_preselect_naflags, sizeof(ap->ap_preselect_naflags));
TAILQ_INIT(&ap->ap_preselect_list);
ap->ap_preselect_mode = AUDITPIPE_PRESELECT_MODE_TRAIL;
/*
* Add to global list and update global statistics.
*/
TAILQ_INSERT_HEAD(&audit_pipe_list, ap, ap_list);
audit_pipe_count++;
audit_pipe_ever++;
return (ap);
}
/*
* Flush all records currently present in an audit pipe; assume mutex is held.
*/
static void
audit_pipe_flush(struct audit_pipe *ap)
{
struct audit_pipe_entry *ape;
AUDIT_PIPE_LOCK_ASSERT(ap);
while ((ape = TAILQ_FIRST(&ap->ap_queue)) != NULL) {
TAILQ_REMOVE(&ap->ap_queue, ape, ape_queue);
ap->ap_qbyteslen -= ape->ape_record_len;
audit_pipe_entry_free(ape);
ap->ap_qlen--;
}
ap->ap_qoffset = 0;
KASSERT(ap->ap_qlen == 0, ("audit_pipe_free: ap_qbyteslen"));
KASSERT(ap->ap_qbyteslen == 0, ("audit_pipe_flush: ap_qbyteslen"));
}
/*
* Free an audit pipe; this means freeing all preselection state and all
* records in the pipe. Assumes global write lock and pipe mutex are held to
* prevent any new records from being inserted during the free, and that the
* audit pipe is still on the global list.
*/
static void
audit_pipe_free(struct audit_pipe *ap)
{
AUDIT_PIPE_LIST_WLOCK_ASSERT();
AUDIT_PIPE_LOCK_ASSERT(ap);
audit_pipe_preselect_flush_locked(ap);
audit_pipe_flush(ap);
cv_destroy(&ap->ap_cv);
AUDIT_PIPE_SX_LOCK_DESTROY(ap);
AUDIT_PIPE_LOCK_DESTROY(ap);
seldrain(&ap->ap_selinfo);
knlist_destroy(&ap->ap_selinfo.si_note);
TAILQ_REMOVE(&audit_pipe_list, ap, ap_list);
free(ap, M_AUDIT_PIPE);
audit_pipe_count--;
}
/*
* Audit pipe clone routine -- provide specific requested audit pipe, or a
* fresh one if a specific one is not requested.
*/
static void
audit_pipe_clone(void *arg, struct ucred *cred, char *name, int namelen,
struct cdev **dev)
{
int i, u;
if (*dev != NULL)
return;
if (strcmp(name, AUDIT_PIPE_NAME) == 0)
u = -1;
else if (dev_stdclone(name, NULL, AUDIT_PIPE_NAME, &u) != 1)
return;
i = clone_create(&audit_pipe_clones, &audit_pipe_cdevsw, &u, dev, 0);
if (i) {
*dev = make_dev(&audit_pipe_cdevsw, u, UID_ROOT,
GID_WHEEL, 0600, "%s%d", AUDIT_PIPE_NAME, u);
if (*dev != NULL) {
dev_ref(*dev);
(*dev)->si_flags |= SI_CHEAPCLONE;
}
}
}
/*
* Audit pipe open method. Explicit privilege check isn't used as this
* allows file permissions on the special device to be used to grant audit
* review access. Those file permissions should be managed carefully.
*/
static int
audit_pipe_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
struct audit_pipe *ap;
AUDIT_PIPE_LIST_WLOCK();
ap = dev->si_drv1;
if (ap == NULL) {
ap = audit_pipe_alloc();
if (ap == NULL) {
AUDIT_PIPE_LIST_WUNLOCK();
return (ENOMEM);
}
dev->si_drv1 = ap;
} else {
KASSERT(ap->ap_open, ("audit_pipe_open: ap && !ap_open"));
AUDIT_PIPE_LIST_WUNLOCK();
return (EBUSY);
}
ap->ap_open = 1; /* No lock required yet. */
AUDIT_PIPE_LIST_WUNLOCK();
fsetown(td->td_proc->p_pid, &ap->ap_sigio);
return (0);
}
/*
* Close audit pipe, tear down all records, etc.
*/
static int
audit_pipe_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
{
struct audit_pipe *ap;
ap = dev->si_drv1;
KASSERT(ap != NULL, ("audit_pipe_close: ap == NULL"));
KASSERT(ap->ap_open, ("audit_pipe_close: !ap_open"));
funsetown(&ap->ap_sigio);
AUDIT_PIPE_LIST_WLOCK();
AUDIT_PIPE_LOCK(ap);
ap->ap_open = 0;
audit_pipe_free(ap);
dev->si_drv1 = NULL;
AUDIT_PIPE_LIST_WUNLOCK();
return (0);
}
/*
* Audit pipe ioctl() routine. Handle file descriptor and audit pipe layer
* commands.
*/
static int
audit_pipe_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag,
struct thread *td)
{
struct auditpipe_ioctl_preselect *aip;
struct audit_pipe *ap;
au_mask_t *maskp;
int error, mode;
au_id_t auid;
ap = dev->si_drv1;
KASSERT(ap != NULL, ("audit_pipe_ioctl: ap == NULL"));
/*
* Audit pipe ioctls: first come standard device node ioctls, then
* manipulation of pipe settings, and finally, statistics query
* ioctls.
*/
switch (cmd) {
case FIONBIO:
AUDIT_PIPE_LOCK(ap);
if (*(int *)data)
ap->ap_flags |= AUDIT_PIPE_NBIO;
else
ap->ap_flags &= ~AUDIT_PIPE_NBIO;
AUDIT_PIPE_UNLOCK(ap);
error = 0;
break;
case FIONREAD:
AUDIT_PIPE_LOCK(ap);
*(int *)data = ap->ap_qbyteslen - ap->ap_qoffset;
AUDIT_PIPE_UNLOCK(ap);
error = 0;
break;
case FIOASYNC:
AUDIT_PIPE_LOCK(ap);
if (*(int *)data)
ap->ap_flags |= AUDIT_PIPE_ASYNC;
else
ap->ap_flags &= ~AUDIT_PIPE_ASYNC;
AUDIT_PIPE_UNLOCK(ap);
error = 0;
break;
case FIOSETOWN:
error = fsetown(*(int *)data, &ap->ap_sigio);
break;
case FIOGETOWN:
*(int *)data = fgetown(&ap->ap_sigio);
error = 0;
break;
case AUDITPIPE_GET_QLEN:
*(u_int *)data = ap->ap_qlen;
error = 0;
break;
case AUDITPIPE_GET_QLIMIT:
*(u_int *)data = ap->ap_qlimit;
error = 0;
break;
case AUDITPIPE_SET_QLIMIT:
/* Lockless integer write. */
if (*(u_int *)data >= AUDIT_PIPE_QLIMIT_MIN ||
*(u_int *)data <= AUDIT_PIPE_QLIMIT_MAX) {
ap->ap_qlimit = *(u_int *)data;
error = 0;
} else
error = EINVAL;
break;
case AUDITPIPE_GET_QLIMIT_MIN:
*(u_int *)data = AUDIT_PIPE_QLIMIT_MIN;
error = 0;
break;
case AUDITPIPE_GET_QLIMIT_MAX:
*(u_int *)data = AUDIT_PIPE_QLIMIT_MAX;
error = 0;
break;
case AUDITPIPE_GET_PRESELECT_FLAGS:
AUDIT_PIPE_LOCK(ap);
maskp = (au_mask_t *)data;
*maskp = ap->ap_preselect_flags;
AUDIT_PIPE_UNLOCK(ap);
error = 0;
break;
case AUDITPIPE_SET_PRESELECT_FLAGS:
AUDIT_PIPE_LOCK(ap);
maskp = (au_mask_t *)data;
ap->ap_preselect_flags = *maskp;
AUDIT_PIPE_UNLOCK(ap);
error = 0;
break;
case AUDITPIPE_GET_PRESELECT_NAFLAGS:
AUDIT_PIPE_LOCK(ap);
maskp = (au_mask_t *)data;
*maskp = ap->ap_preselect_naflags;
AUDIT_PIPE_UNLOCK(ap);
error = 0;
break;
case AUDITPIPE_SET_PRESELECT_NAFLAGS:
AUDIT_PIPE_LOCK(ap);
maskp = (au_mask_t *)data;
ap->ap_preselect_naflags = *maskp;
AUDIT_PIPE_UNLOCK(ap);
error = 0;
break;
case AUDITPIPE_GET_PRESELECT_AUID:
aip = (struct auditpipe_ioctl_preselect *)data;
error = audit_pipe_preselect_get(ap, aip->aip_auid,
&aip->aip_mask);
break;
case AUDITPIPE_SET_PRESELECT_AUID:
aip = (struct auditpipe_ioctl_preselect *)data;
audit_pipe_preselect_set(ap, aip->aip_auid, aip->aip_mask);
error = 0;
break;
case AUDITPIPE_DELETE_PRESELECT_AUID:
auid = *(au_id_t *)data;
error = audit_pipe_preselect_delete(ap, auid);
break;
case AUDITPIPE_FLUSH_PRESELECT_AUID:
audit_pipe_preselect_flush(ap);
error = 0;
break;
case AUDITPIPE_GET_PRESELECT_MODE:
AUDIT_PIPE_LOCK(ap);
*(int *)data = ap->ap_preselect_mode;
AUDIT_PIPE_UNLOCK(ap);
error = 0;
break;
case AUDITPIPE_SET_PRESELECT_MODE:
mode = *(int *)data;
switch (mode) {
case AUDITPIPE_PRESELECT_MODE_TRAIL:
case AUDITPIPE_PRESELECT_MODE_LOCAL:
AUDIT_PIPE_LOCK(ap);
ap->ap_preselect_mode = mode;
AUDIT_PIPE_UNLOCK(ap);
error = 0;
break;
default:
error = EINVAL;
}
break;
case AUDITPIPE_FLUSH:
if (AUDIT_PIPE_SX_XLOCK_SIG(ap) != 0)
return (EINTR);
AUDIT_PIPE_LOCK(ap);
audit_pipe_flush(ap);
AUDIT_PIPE_UNLOCK(ap);
AUDIT_PIPE_SX_XUNLOCK(ap);
error = 0;
break;
case AUDITPIPE_GET_MAXAUDITDATA:
*(u_int *)data = MAXAUDITDATA;
error = 0;
break;
case AUDITPIPE_GET_INSERTS:
*(u_int *)data = ap->ap_inserts;
error = 0;
break;
case AUDITPIPE_GET_READS:
*(u_int *)data = ap->ap_reads;
error = 0;
break;
case AUDITPIPE_GET_DROPS:
*(u_int *)data = ap->ap_drops;
error = 0;
break;
case AUDITPIPE_GET_TRUNCATES:
*(u_int *)data = 0;
error = 0;
break;
default:
error = ENOTTY;
}
return (error);
}
/*
* Audit pipe read. Read one or more partial or complete records to user
* memory.
*/
static int
audit_pipe_read(struct cdev *dev, struct uio *uio, int flag)
{
struct audit_pipe_entry *ape;
struct audit_pipe *ap;
u_int toread;
int error;
ap = dev->si_drv1;
KASSERT(ap != NULL, ("audit_pipe_read: ap == NULL"));
/*
* We hold an sx(9) lock over read and flush because we rely on the
* stability of a record in the queue during uiomove(9).
*/
if (AUDIT_PIPE_SX_XLOCK_SIG(ap) != 0)
return (EINTR);
AUDIT_PIPE_LOCK(ap);
while (TAILQ_EMPTY(&ap->ap_queue)) {
if (ap->ap_flags & AUDIT_PIPE_NBIO) {
AUDIT_PIPE_UNLOCK(ap);
AUDIT_PIPE_SX_XUNLOCK(ap);
return (EAGAIN);
}
error = cv_wait_sig(&ap->ap_cv, AUDIT_PIPE_MTX(ap));
if (error) {
AUDIT_PIPE_UNLOCK(ap);
AUDIT_PIPE_SX_XUNLOCK(ap);
return (error);
}
}
/*
* Copy as many remaining bytes from the current record to userspace
* as we can. Keep processing records until we run out of records in
* the queue, or until the user buffer runs out of space.
*
* Note: we rely on the SX lock to maintain ape's stability here.
*/
ap->ap_reads++;
while ((ape = TAILQ_FIRST(&ap->ap_queue)) != NULL &&
uio->uio_resid > 0) {
AUDIT_PIPE_LOCK_ASSERT(ap);
KASSERT(ape->ape_record_len > ap->ap_qoffset,
("audit_pipe_read: record_len > qoffset (1)"));
toread = MIN(ape->ape_record_len - ap->ap_qoffset,
uio->uio_resid);
AUDIT_PIPE_UNLOCK(ap);
error = uiomove((char *)ape->ape_record + ap->ap_qoffset,
toread, uio);
if (error) {
AUDIT_PIPE_SX_XUNLOCK(ap);
return (error);
}
/*
* If the copy succeeded, update book-keeping, and if no
* bytes remain in the current record, free it.
*/
AUDIT_PIPE_LOCK(ap);
KASSERT(TAILQ_FIRST(&ap->ap_queue) == ape,
("audit_pipe_read: queue out of sync after uiomove"));
ap->ap_qoffset += toread;
KASSERT(ape->ape_record_len >= ap->ap_qoffset,
("audit_pipe_read: record_len >= qoffset (2)"));
if (ap->ap_qoffset == ape->ape_record_len) {
TAILQ_REMOVE(&ap->ap_queue, ape, ape_queue);
ap->ap_qbyteslen -= ape->ape_record_len;
audit_pipe_entry_free(ape);
ap->ap_qlen--;
ap->ap_qoffset = 0;
}
}
AUDIT_PIPE_UNLOCK(ap);
AUDIT_PIPE_SX_XUNLOCK(ap);
return (0);
}
/*
* Audit pipe poll.
*/
static int
audit_pipe_poll(struct cdev *dev, int events, struct thread *td)
{
struct audit_pipe *ap;
int revents;
revents = 0;
ap = dev->si_drv1;
KASSERT(ap != NULL, ("audit_pipe_poll: ap == NULL"));
if (events & (POLLIN | POLLRDNORM)) {
AUDIT_PIPE_LOCK(ap);
if (TAILQ_FIRST(&ap->ap_queue) != NULL)
revents |= events & (POLLIN | POLLRDNORM);
else
selrecord(td, &ap->ap_selinfo);
AUDIT_PIPE_UNLOCK(ap);
}
return (revents);
}
/*
* Audit pipe kqfilter.
*/
static int
audit_pipe_kqfilter(struct cdev *dev, struct knote *kn)
{
struct audit_pipe *ap;
ap = dev->si_drv1;
KASSERT(ap != NULL, ("audit_pipe_kqfilter: ap == NULL"));
if (kn->kn_filter != EVFILT_READ)
return (EINVAL);
kn->kn_fop = &audit_pipe_read_filterops;
kn->kn_hook = ap;
AUDIT_PIPE_LOCK(ap);
knlist_add(&ap->ap_selinfo.si_note, kn, 1);
AUDIT_PIPE_UNLOCK(ap);
return (0);
}
/*
* Return true if there are records available for reading on the pipe.
*/
static int
audit_pipe_kqread(struct knote *kn, long hint)
{
struct audit_pipe *ap;
ap = (struct audit_pipe *)kn->kn_hook;
KASSERT(ap != NULL, ("audit_pipe_kqread: ap == NULL"));
AUDIT_PIPE_LOCK_ASSERT(ap);
if (ap->ap_qlen != 0) {
kn->kn_data = ap->ap_qbyteslen - ap->ap_qoffset;
return (1);
} else {
kn->kn_data = 0;
return (0);
}
}
/*
* Detach kqueue state from audit pipe.
*/
static void
audit_pipe_kqdetach(struct knote *kn)
{
struct audit_pipe *ap;
ap = (struct audit_pipe *)kn->kn_hook;
KASSERT(ap != NULL, ("audit_pipe_kqdetach: ap == NULL"));
AUDIT_PIPE_LOCK(ap);
knlist_remove(&ap->ap_selinfo.si_note, kn, 1);
AUDIT_PIPE_UNLOCK(ap);
}
/*
* Initialize the audit pipe system.
*/
static void
audit_pipe_init(void *unused)
{
TAILQ_INIT(&audit_pipe_list);
AUDIT_PIPE_LIST_LOCK_INIT();
clone_setup(&audit_pipe_clones);
audit_pipe_eh_tag = EVENTHANDLER_REGISTER(dev_clone,
audit_pipe_clone, 0, 1000);
if (audit_pipe_eh_tag == NULL)
panic("audit_pipe_init: EVENTHANDLER_REGISTER");
}
SYSINIT(audit_pipe_init, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, audit_pipe_init,
NULL);