PERFORCE change 84875 for review
Wayne Salamon
wsalamon at FreeBSD.org
Thu Oct 6 01:10:18 GMT 2005
http://perforce.freebsd.org/chv.cgi?CH=84875
Change 84875 by wsalamon at gretsch on 2005/10/06 01:09:55
Move the audit_arg_xxx() functions into the new source file and
add the new file to the config.
Affected files ...
.. //depot/projects/trustedbsd/audit3/sys/conf/files#9 edit
.. //depot/projects/trustedbsd/audit3/sys/security/audit/audit_arg.c#2 edit
.. //depot/projects/trustedbsd/audit3/sys/security/audit/kern_audit.c#45 edit
Differences ...
==== //depot/projects/trustedbsd/audit3/sys/conf/files#9 (text+ko) ====
@@ -1843,8 +1843,9 @@
posix4/p1003_1b.c standard
posix4/posix4_mib.c standard
rpc/rpcclnt.c optional nfsclient
+security/audit/audit_arg.c optional audit
+security/audit/audit_syscalls.c standard
security/audit/audit_trigger.c optional audit
-security/audit/audit_syscalls.c standard
security/audit/kern_audit.c optional audit
security/audit/kern_bsm_audit.c optional audit
security/audit/kern_bsm_klib.c optional audit
==== //depot/projects/trustedbsd/audit3/sys/security/audit/audit_arg.c#2 (text+ko) ====
@@ -21,985 +21,25 @@
*/
#include <sys/param.h>
-#include <sys/condvar.h>
-#include <sys/conf.h>
-#include <sys/file.h>
#include <sys/filedesc.h>
-#include <sys/fcntl.h>
#include <sys/ipc.h>
-#include <sys/kernel.h>
-#include <sys/kthread.h>
-#include <sys/malloc.h>
#include <sys/mount.h>
-#include <sys/namei.h>
#include <sys/proc.h>
-#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/domain.h>
-#include <sys/sysproto.h>
-#include <sys/sysent.h>
#include <sys/systm.h>
-#include <sys/ucred.h>
-#include <sys/uio.h>
#include <sys/un.h>
-#include <sys/unistd.h>
#include <sys/vnode.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
-#include <bsm/audit.h>
-#include <bsm/audit_kevents.h>
#include <security/audit/audit.h>
#include <security/audit/audit_private.h>
/*
- * The AUDIT_EXCESSIVELY_VERBOSE define enables a number of
- * gratuitously noisy printf's to the console. Due to the
- * volume, it should be left off unless you want your system
- * to churn a lot whenever the audit record flow gets high.
- */
-//#define AUDIT_EXCESSIVELY_VERBOSE
-#ifdef AUDIT_EXCESSIVELY_VERBOSE
-#define AUDIT_PRINTF(x) printf x
-#else
-#define AUDIT_PRINTF(X)
-#endif
-
-#if 0
-#if DIAGNOSTIC
-#if defined(assert)
-#undef assert()
-#endif
-#define assert(cond) \
- ((void) ((cond) ? 0 : panic("%s:%d (%s)", __FILE__, __LINE__, # cond)))
-#else
-#include <kern/assert.h>
-#endif /* DIAGNOSTIC */
-#endif
-#define assert(x) KASSERT(x, x)
-
-MALLOC_DEFINE(M_AUDIT, "audit", "Audit event records");
-
-/*
- * 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;
-
-/*
- * 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;
-
-/*
- * Audit queue control settings (minimum free, low/high water marks, etc.)
- */
-struct au_qctrl audit_qctrl;
-
-/*
- * Global audit statistiscs.
- */
-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.
- */
-static 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.
- */
-static TAILQ_HEAD(, kaudit_record) audit_q;
-static int audit_q_len;
-static int audit_pre_q_len;
-
-/*
- * 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.
- */
-static struct cv audit_cv;
-
-/*
- * Worker thread that will schedule disk I/O, etc.
- */
-static struct proc *audit_thread;
-
-/*
- * When an audit log is rotated, the actual rotation must be performed
- * by the audit worker thread, as it may have outstanding writes on the
- * current audit log. audit_replacement_vp holds the vnode replacing
- * the current vnode. We can't let more than one replacement occur
- * at a time, so if more than one thread requests a replacement, only
- * one can have the replacement "in progress" at any given moment. If
- * a thread tries to replace the audit vnode and discovers a replacement
- * is already in progress (i.e., audit_replacement_flag != 0), then it
- * will sleep on audit_replacement_cv waiting its turn to perform a
- * replacement. When a replacement is completed, this cv is signalled
- * by the worker thread so a waiting thread can start another replacement.
- * We also store a credential to perform audit log write operations with.
- *
- * The current credential and vnode are thread-local to audit_worker.
- */
-static struct cv audit_replacement_cv;
-
-static int audit_replacement_flag;
-static struct vnode *audit_replacement_vp;
-static struct ucred *audit_replacement_cred;
-
-/*
- * 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.
- */
-static struct cv audit_commit_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;
-
-/*
- * Flags related to Kernel->user-space communication.
- */
-static int audit_file_rotate_wait;
-
-/*
- * Are we currently "failing stop" due to out of disk space?
- */
-static int audit_in_failure;
-
-/*
- * Perform a deep free of an audit record (core record and referenced objects)
- */
-static void
-audit_record_free(struct kaudit_record *ar)
-{
-
- if (ar->k_ar.ar_arg_upath1 != NULL) {
- free(ar->k_ar.ar_arg_upath1, M_AUDIT);
- }
- if (ar->k_ar.ar_arg_upath2 != NULL) {
- free(ar->k_ar.ar_arg_upath2, M_AUDIT);
- }
- if (ar->k_ar.ar_arg_kpath1 != NULL) {
- free(ar->k_ar.ar_arg_kpath1, M_AUDIT);
- }
- if (ar->k_ar.ar_arg_kpath2 != NULL) {
- free(ar->k_ar.ar_arg_kpath2, M_AUDIT);
- }
- if (ar->k_ar.ar_arg_text != NULL) {
- free(ar->k_ar.ar_arg_text, M_AUDIT);
- }
- if (ar->k_udata != NULL) {
- free(ar->k_udata, M_AUDIT);
- }
- free(ar, M_AUDIT);
-}
-
-/*
- * XXXAUDIT: Should adjust comments below to make it clear that we get to
- * this point only if we believe we have storage, so not having space here
- * is a violation of invariants derived from administrative procedures.
- * I.e., someone else has written to the audit partition, leaving less space
- * than we accounted for.
- */
-static int
-audit_record_write(struct vnode *vp, struct kaudit_record *ar,
- struct ucred *cred, struct thread *td)
-{
- int ret;
- long temp;
- struct au_record *bsm;
- struct vattr vattr;
- struct statfs *mnt_stat = &vp->v_mount->mnt_stat;
- int vfslocked;
-
- vfslocked = VFS_LOCK_GIANT(vp->v_mount);
-
- /*
- * First, gather statistics on the audit log file and file system
- * so that we know how we're doing on space. In both cases,
- * if we're unable to perform the operation, we drop the record
- * and return. However, this is arguably an assertion failure.
- * XXX Need a FreeBSD equivalent.
- */
- ret = VFS_STATFS(vp->v_mount, mnt_stat, td);
- if (ret)
- goto out;
-
- ret = VOP_GETATTR(vp, &vattr, cred, td);
- if (ret)
- goto out;
-
- /* update the global stats struct */
- audit_fstat.af_currsz = vattr.va_size;
-
- /*
- * XXX Need to decide what to do if the trigger to the audit daemon
- * fails.
- */
-
- /*
- * If we fall below minimum free blocks (hard limit), tell the audit
- * daemon to force a rotation off of the file system. We also stop
- * writing, which means this audit record is probably lost.
- * If we fall below the minimum percent free blocks (soft limit),
- * then kindly suggest to the audit daemon to do something.
- */
- if (mnt_stat->f_bfree < AUDIT_HARD_LIMIT_FREE_BLOCKS) {
- send_trigger(AUDIT_TRIGGER_NO_SPACE);
- /* Hopefully userspace did something about all the previous
- * triggers that were sent prior to this critical condition.
- * If fail-stop is set, then we're done; goodnight Gracie.
- */
- if (audit_fail_stop)
- panic("Audit log space exhausted and fail-stop set.");
- else {
- audit_suspended = 1;
- ret = ENOSPC;
- goto out;
- }
- } else
- /*
- * Send a message to the audit daemon that disk space
- * is getting low.
- *
- * XXXAUDIT: Check math and block size calculation here.
- */
- if (audit_qctrl.aq_minfree != 0) {
- temp = mnt_stat->f_blocks / (100 /
- audit_qctrl.aq_minfree);
- if (mnt_stat->f_bfree < temp)
- send_trigger(AUDIT_TRIGGER_LOW_SPACE);
- }
-
- /* Check if the current log file is full; if so, call for
- * a log rotate. This is not an exact comparison; we may
- * write some records over the limit. If that's not
- * acceptable, then add a fudge factor here.
- */
- if ((audit_fstat.af_filesz != 0) &&
- (audit_file_rotate_wait == 0) &&
- (vattr.va_size >= audit_fstat.af_filesz)) {
- audit_file_rotate_wait = 1;
- send_trigger(AUDIT_TRIGGER_OPEN_NEW);
- }
-
- /*
- * If the estimated amount of audit data in the audit event queue
- * (plus records allocated but not yet queued) has reached the
- * amount of free space on the disk, then we need to go into an
- * audit fail stop state, in which we do not permit the
- * allocation/committing of any new audit records. We continue to
- * process packets but don't allow any activities that might
- * generate new records. In the future, we might want to detect
- * when space is available again and allow operation to continue,
- * but this behavior is sufficient to meet fail stop requirements
- * in CAPP.
- */
- if (audit_fail_stop &&
- (unsigned long)
- ((audit_q_len + audit_pre_q_len + 1) * MAX_AUDIT_RECORD_SIZE) /
- mnt_stat->f_bsize >= (unsigned long)(mnt_stat->f_bfree)) {
- printf(
- "audit_worker: free space below size of audit queue, failing stop\n");
- audit_in_failure = 1;
- }
-
- /*
- * If there is a user audit record attached to the kernel record,
- * then write the user record.
- */
- /* XXX Need to decide a few things here: IF the user audit
- * record is written, but the write of the kernel record fails,
- * what to do? Should the kernel record come before or after the
- * user record? For now, we write the user record first, and
- * we ignore errors.
- */
- if (ar->k_ar_commit & AR_COMMIT_USER) {
- ret = vn_rdwr(UIO_WRITE, vp, (void *)ar->k_udata, ar->k_ulen,
- (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, cred, NULL,
- NULL, td);
- if (ret)
- goto out;
- }
-
- /*
- * Convert the internal kernel record to BSM format and write it
- * out if everything's OK.
- */
- if (!(ar->k_ar_commit & AR_COMMIT_KERNEL)) {
- ret = 0;
- goto out;
- }
-
- /*
- * XXXAUDIT: Should we actually allow this conversion to fail? With
- * sleeping memory allocation and invariants checks, perhaps not.
- */
- ret = kaudit_to_bsm(ar, &bsm);
- if (ret == BSM_NOAUDIT) {
- ret = 0;
- goto out;
- }
-
- /*
- * XXX: We drop the record on BSM conversion failure, but really
- * this is an assertion failure.
- */
- if (ret == BSM_FAILURE) {
- AUDIT_PRINTF(("BSM conversion failure\n"));
- ret = EINVAL;
- goto out;
- }
-
- /*
- * XXX
- * We should break the write functionality away from the BSM record
- * generation and have the BSM generation done before this function
- * is called. This function will then take the BSM record as a
- * parameter.
- */
- ret = (vn_rdwr(UIO_WRITE, vp, (void *)bsm->data, bsm->len,
- (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, cred, NULL, NULL, td));
-
- kau_free(bsm);
-
-out:
- /*
- * When we're done processing the current record, we have to
- * check to see if we're in a failure mode, and if so, whether
- * this was the last record left to be drained. If we're done
- * draining, then we fsync the vnode and panic.
- */
- if (audit_in_failure &&
- audit_q_len == 0 && audit_pre_q_len == 0) {
- VOP_LOCK(vp, LK_DRAIN | LK_INTERLOCK, td);
- (void)VOP_FSYNC(vp, MNT_WAIT, td);
- VOP_UNLOCK(vp, 0, td);
- panic("Audit store overflow; record queue drained.");
- }
-
- VFS_UNLOCK_GIANT(vfslocked);
-
- return (ret);
-}
-
-/*
- * The audit_worker thread is responsible for watching the event queue,
- * dequeueing records, converting them to BSM format, and committing them to
- * disk. In order to minimize lock thrashing, records are dequeued in sets
- * to a thread-local work queue. In addition, the audit_work performs the
- * actual exchange of audit log vnode pointer, as audit_vp is a thread-local
- * variable.
- */
-static void
-audit_worker(void *arg)
-{
- int do_replacement_signal, error;
- TAILQ_HEAD(, kaudit_record) ar_worklist;
- struct kaudit_record *ar;
- struct vnode *audit_vp, *old_vp;
- int vfslocked;
-
- struct ucred *audit_cred, *old_cred;
- struct thread *audit_td;
-
- AUDIT_PRINTF(("audit_worker starting\n"));
-
- /*
- * These are thread-local variables requiring no synchronization.
- */
- TAILQ_INIT(&ar_worklist);
- audit_cred = NULL;
- audit_td = curthread;
- audit_vp = NULL;
-
- mtx_lock(&audit_mtx);
- while (1) {
- /*
- * First priority: replace the audit log target if requested.
- * Accessing the vnode here requires dropping the audit_mtx;
- * in case another replacement was scheduled while the mutex
- * was released, we loop.
- *
- * XXX It could well be we should drain existing records
- * first to ensure that the timestamps and ordering
- * are right.
- */
- do_replacement_signal = 0;
- while (audit_replacement_flag != 0) {
- old_cred = audit_cred;
- old_vp = audit_vp;
- audit_cred = audit_replacement_cred;
- audit_vp = audit_replacement_vp;
- audit_replacement_cred = NULL;
- audit_replacement_vp = NULL;
- audit_replacement_flag = 0;
-
- audit_enabled = (audit_vp != NULL);
-
- /*
- * XXX: What to do about write failures here?
- */
- if (old_vp != NULL) {
- AUDIT_PRINTF(("Closing old audit file\n"));
- mtx_unlock(&audit_mtx);
- vfslocked = VFS_LOCK_GIANT(old_vp->v_mount);
- vn_close(old_vp, AUDIT_CLOSE_FLAGS, old_cred,
- audit_td);
- VFS_UNLOCK_GIANT(vfslocked);
- crfree(old_cred);
- mtx_lock(&audit_mtx);
- old_cred = NULL;
- old_vp = NULL;
- AUDIT_PRINTF(("Audit file closed\n"));
- }
- if (audit_vp != NULL) {
- AUDIT_PRINTF(("Opening new audit file\n"));
- }
- do_replacement_signal = 1;
- }
- /*
- * Signal that replacement have occurred to wake up and
- * start any other replacements started in parallel. We can
- * continue about our business in the mean time. We
- * broadcast so that both new replacements can be inserted,
- * but also so that the source(s) of replacement can return
- * successfully.
- */
- if (do_replacement_signal)
- cv_broadcast(&audit_replacement_cv);
-
- /*
- * Next, check to see if we have any records to drain into
- * the vnode. If not, go back to waiting for an event.
- */
- if (TAILQ_EMPTY(&audit_q)) {
- AUDIT_PRINTF(("audit_worker waiting\n"));
- cv_wait(&audit_cv, &audit_mtx);
- AUDIT_PRINTF(("audit_worker woken up\n"));
- AUDIT_PRINTF(("audit_worker: new vp = %p; value of flag %d\n",
- audit_replacement_vp, audit_replacement_flag));
- continue;
- }
-
- /*
- * If we have records, but there's no active vnode to
- * write to, drain the record queue. Generally, we
- * prevent the unnecessary allocation of records
- * elsewhere, but we need to allow for races between
- * conditional allocation and queueing. Go back to
- * waiting when we're done.
- *
- * XXX: We go out of our way to avoid calling
- * audit_record_free().
- * with the audit_mtx held, to avoid a lock order reversal
- * as free() may grab Giant. This should be fixed at
- * some point.
- */
- if (audit_vp == NULL) {
- while ((ar = TAILQ_FIRST(&audit_q))) {
- TAILQ_REMOVE(&audit_q, ar, k_q);
- audit_q_len--;
- if (audit_q_len <= audit_qctrl.aq_lowater)
- cv_broadcast(&audit_commit_cv);
-
- TAILQ_INSERT_TAIL(&ar_worklist, ar, k_q);
- }
- mtx_unlock(&audit_mtx);
- while ((ar = TAILQ_FIRST(&ar_worklist))) {
- TAILQ_REMOVE(&ar_worklist, ar, k_q);
- audit_record_free(ar);
- }
- mtx_lock(&audit_mtx);
- continue;
- }
-
- /*
- * We have both records to write and an active vnode
- * to write to. Dequeue a record, and start the write.
- * Eventually, it might make sense to dequeue several
- * records and perform our own clustering, if the lower
- * layers aren't doing it automatically enough.
- *
- * XXX: We go out of our way to avoid calling
- * audit_record_free()
- * with the audit_mtx held, to avoid a lock order reversal
- * as free() may grab Giant. This should be fixed at
- * some point.
- *
- * XXXAUDIT: free() no longer grabs Giant.
- */
- while ((ar = TAILQ_FIRST(&audit_q))) {
- TAILQ_REMOVE(&audit_q, ar, k_q);
- audit_q_len--;
- if (audit_q_len <= audit_qctrl.aq_lowater)
- cv_broadcast(&audit_commit_cv);
-
- TAILQ_INSERT_TAIL(&ar_worklist, ar, k_q);
- }
-
- mtx_unlock(&audit_mtx);
- while ((ar = TAILQ_FIRST(&ar_worklist))) {
- TAILQ_REMOVE(&ar_worklist, ar, k_q);
- if (audit_vp != NULL) {
- error = audit_record_write(audit_vp, ar,
- audit_cred, audit_td);
- if (error && audit_panic_on_write_fail)
- panic("audit_worker: write error %d\n",
- error);
- else if (error)
- printf("audit_worker: write error %d\n",
- error);
- }
- audit_record_free(ar);
- }
- mtx_lock(&audit_mtx);
- }
-}
-
-/*
- * 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.
- */
-static void
-audit_init(void)
-{
- int error;
-
- printf("Security auditing service present\n");
- TAILQ_INIT(&audit_q);
- audit_q_len = 0;
- audit_pre_q_len = 0;
- audit_enabled = 0;
- audit_suspended = 0;
- audit_replacement_cred = NULL;
- audit_replacement_flag = 0;
- audit_file_rotate_wait = 0;
- audit_replacement_vp = NULL;
- audit_fstat.af_filesz = 0; /* '0' means unset, unbounded */
- audit_fstat.af_currsz = 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;
-
- mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF);
- cv_init(&audit_cv, "audit_cv");
- cv_init(&audit_replacement_cv, "audit_replacement_cv");
- cv_init(&audit_commit_cv, "audit_commit_cv");
- cv_init(&audit_fail_cv, "audit_fail_cv");
-
- /* Initialize the BSM audit subsystem. */
- kau_init();
-
- audit_trigger_init();
-
- /* Register shutdown handler. */
- EVENTHANDLER_REGISTER(shutdown_pre_sync, audit_shutdown, NULL,
- SHUTDOWN_PRI_FIRST);
-
- error = kthread_create(audit_worker, NULL, &audit_thread, RFHIGHPID,
- 0, "audit_worker");
- if (error != 0)
- panic("audit_init: kthread_create returned %d", error);
-}
-
-SYSINIT(audit_init, SI_SUB_AUDIT, SI_ORDER_FIRST, audit_init, NULL)
-
-/*
- * audit_rotate_vnode() is called by a user or kernel thread to configure or
- * de-configure auditing on a vnode. The arguments are the replacement
- * credential and vnode to substitute for the current credential and vnode,
- * if any. If either is set to NULL, both should be NULL, and this is used
- * to indicate that audit is being disabled. The real work is done in the
- * audit_worker thread, but audit_rotate_vnode() waits synchronously for that
- * to complete.
- *
- * The vnode should be referenced and opened by the caller. The credential
- * should be referenced. audit_rotate_vnode() will own both references as of
- * this call, so the caller should not release either.
- *
- * XXXAUDIT: Review synchronize communication logic. Really, this is a
- * message queue of depth 1.
- *
- * XXXAUDIT: Enhance the comments below to indicate that we are basically
- * acquiring ownership of the communications queue, inserting our message,
- * and waiting for an acknowledgement.
- */
-void
-audit_rotate_vnode(struct ucred *cred, struct vnode *vp)
-{
-
- /*
- * If other parallel log replacements have been requested, we wait
- * until they've finished before continuing.
- */
- mtx_lock(&audit_mtx);
- while (audit_replacement_flag != 0) {
- AUDIT_PRINTF(("audit_rotate_vnode: sleeping to wait for "
- "flag\n"));
- cv_wait(&audit_replacement_cv, &audit_mtx);
- AUDIT_PRINTF(("audit_rotate_vnode: woken up (flag %d)\n",
- audit_replacement_flag));
- }
- audit_replacement_cred = cred;
- audit_replacement_flag = 1;
- audit_replacement_vp = vp;
-
- /*
- * Wake up the audit worker to perform the exchange once we
- * release the mutex.
- */
- cv_signal(&audit_cv);
-
- /*
- * Wait for the audit_worker to broadcast that a replacement has
- * taken place; we know that once this has happened, our vnode
- * has been replaced in, so we can return successfully.
- */
- AUDIT_PRINTF(("audit_rotate_vnode: waiting for news of "
- "replacement\n"));
- cv_wait(&audit_replacement_cv, &audit_mtx);
- AUDIT_PRINTF(("audit_rotate_vnode: change acknowledged by "
- "audit_worker (flag " "now %d)\n", audit_replacement_flag));
- mtx_unlock(&audit_mtx);
-
- audit_file_rotate_wait = 0; /* We can now request another rotation */
-}
-
-/*
- * 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 *arg, int howto)
-{
-
- audit_rotate_vnode(NULL, NULL);
-}
-
-/*
- * Return the current thread's audit record, if any.
- */
-__inline__ struct kaudit_record *
-currecord(void)
-{
-
- return (curthread->td_ar);
-}
-
-/*
- * MPSAFE
- *
- * 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, struct thread *td)
-{
- struct kaudit_record *ar;
- int no_record;
-
- /*
- * Eventually, there may be certain classes of events that
- * we will audit regardless of the audit state at the time
- * the record is created. These events will generally
- * correspond to changes in the audit state. The dummy
- * code below is from our first prototype, but may also
- * be used in the final version (with modified event numbers).
- */
-#if 0
- if (event != AUDIT_EVENT_FILESTOP && event != AUDIT_EVENT_FILESTART) {
-#endif
- mtx_lock(&audit_mtx);
- no_record = (audit_suspended || !audit_enabled);
- mtx_unlock(&audit_mtx);
- if (no_record)
- return (NULL);
-#if 0
- }
-#endif
-
- /*
- * Initialize the audit record header.
- * XXX: We may want to fail-stop if allocation fails.
- * XXX: The number of outstanding uncommitted audit records is
- * limited by the number of concurrent threads servicing system
- * calls in the kernel.
- */
-
- ar = malloc(sizeof(*ar), M_AUDIT, M_WAITOK);
- if (ar == NULL)
- return NULL;
-
- mtx_lock(&audit_mtx);
- audit_pre_q_len++;
- mtx_unlock(&audit_mtx);
-
- bzero(ar, sizeof(*ar));
- ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC;
- ar->k_ar.ar_event = event;
- nanotime(&ar->k_ar.ar_starttime);
-
- /*
- * Export the subject credential.
- *
- * XXXAUDIT: td_ucred access is OK without proc lock, but some other
- * fields here may require the proc lock.
- */
- cru2x(td->td_ucred, &ar->k_ar.ar_subj_cred);
- ar->k_ar.ar_subj_ruid = td->td_ucred->cr_ruid;
- ar->k_ar.ar_subj_rgid = td->td_ucred->cr_rgid;
- ar->k_ar.ar_subj_egid = td->td_ucred->cr_groups[0];
- ar->k_ar.ar_subj_auid = td->td_proc->p_au->ai_auid;
- ar->k_ar.ar_subj_asid = td->td_proc->p_au->ai_asid;
- ar->k_ar.ar_subj_pid = td->td_proc->p_pid;
- ar->k_ar.ar_subj_amask = td->td_proc->p_au->ai_mask;
- ar->k_ar.ar_subj_term = td->td_proc->p_au->ai_termid;
-
- bcopy(td->td_proc->p_comm, ar->k_ar.ar_subj_comm, MAXCOMLEN);
-
- return (ar);
-}
-
-/*
- * MPSAFE
- */
-void
-audit_commit(struct kaudit_record *ar, int error, int retval)
-{
- int sorf;
- struct au_mask *aumask;
-
- 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.
- *
- * XXXAUDIT: Synchronize access to audit_nae_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 = flags_and_error_to_openevent(
- ar->k_ar.ar_arg_fflags, error);
- break;
-
- case AUE_SYSCTL:
- ar->k_ar.ar_event = 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;
- }
-
- if (au_preselect(ar->k_ar.ar_event, aumask, sorf) != 0)
- ar->k_ar_commit |= AR_COMMIT_KERNEL;
-
- if ((ar->k_ar_commit & (AR_COMMIT_USER | AR_COMMIT_KERNEL)) == 0) {
- mtx_lock(&audit_mtx);
- audit_pre_q_len--;
- mtx_unlock(&audit_mtx);
- audit_record_free(ar);
- return;
- }
-
- ar->k_ar.ar_errno = error;
- ar->k_ar.ar_retval = retval;
-
- /*
- * We might want to do some system-wide post-filtering
- * here at some point.
- */
-
- /*
- * Timestamp system call end.
- */
- nanotime(&ar->k_ar.ar_endtime);
-
- mtx_lock(&audit_mtx);
-
- /*
- * Note: it could be that some records initiated while audit was
- * enabled should still be committed?
- */
- if (audit_suspended || !audit_enabled) {
- audit_pre_q_len--;
- mtx_unlock(&audit_mtx);
- audit_record_free(ar);
- return;
- }
-
- /*
- * Constrain the number of committed audit records based on
- * the configurable parameter.
- */
- while (audit_q_len >= audit_qctrl.aq_hiwater) {
- AUDIT_PRINTF(("audit_commit: sleeping to wait for "
- "audit queue to drain below high water mark\n"));
- cv_wait(&audit_commit_cv, &audit_mtx);
- AUDIT_PRINTF(("audit_commit: woke up waiting for "
- "audit queue draining\n"));
- }
-
- TAILQ_INSERT_TAIL(&audit_q, ar, k_q);
- audit_q_len++;
- audit_pre_q_len--;
- cv_signal(&audit_cv);
- mtx_unlock(&audit_mtx);
-}
-
-/*
- * audit_syscall_enter() is called on entry to eatch 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 short code, struct thread *td)
-{
- int audit_event;
- struct au_mask *aumask;
-
- KASSERT(td->td_ar == NULL, ("audit_syscall_enter: td->td_ar != NULL"));
-
- /*
- * 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.
- *
- * XXXAUDIT: Should we audit that a bad system call was made, and if
- * so, how?
- */
- if (code >= td->td_proc->p_sysent->sv_size)
- return;
-
- audit_event = td->td_proc->p_sysent->sv_table[code].sy_auevent;
- if (audit_event == AUE_NULL)
- return;
-
- /*
- * Check which audit mask to use; either the kernel non-attributable
- * event mask or the process audit mask.
- */
- if (td->td_proc->p_au->ai_auid == AU_DEFAUDITID)
- aumask = &audit_nae_mask;
- else
- aumask = &td->td_proc->p_au->ai_mask;
-
- /*
- * Allocate an audit record, if preselection allows it, and store
- * in the thread for later use.
- */
- if (au_preselect(audit_event, aumask,
- AU_PRS_FAILURE | AU_PRS_SUCCESS)) {
- /*
- * If we're out of space and need to suspend unprivileged
- * processes, do that here rather than trying to allocate
- * another audit record.
- *
- * XXXRW: 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(td) != 0) {
- cv_wait(&audit_fail_cv, &audit_mtx);
- panic("audit_failing_stop: thread continued");
- }
- td->td_ar = audit_new(audit_event, td);
- } else
- td->td_ar = NULL;
-}
-
-/*
- * 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.
- */
-void
-audit_syscall_exit(int error, struct thread *td)
-{
- 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;
>>> TRUNCATED FOR MAIL (1000 lines) <<<
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