Merge Perforce changes 93512, 93514, 93515 from TrustedBSD audit3

branch:

  Integrate audit.c to audit_worker.c, so as to migrate the worker
  thread implementation to its own .c file.

  Populate audit_worker.c using parts now removed from audit.c:

  - Move audit rotation global variables.
  - Move audit_record_write(), audit_worker_rotate(),
    audit_worker_drain(), audit_worker(), audit_rotate_vnode().
  - Create audit_worker_init() from relevant parts of audit_init(),
    which now calls this routine.
  - Recreate audit_free(), which wraps uma_zfree() so that
    audit_record_zone can be static to audit.c.
  - Unstaticize various types and variables relating to the audit
    record queue so that audit_worker can get to them.  We may want
    to wrap these in accessor methods at some point.
  - Move AUDIT_PRINTF() to audit_private.h.

  Addition of audit_worker.c to kernel configuration, missed in
  earlier submit.

Obtained from:	TrustedBSD Project

1 files changed, 27 insertions, 492 deletions

diff --git a/sys/security/audit/audit.c b/sys/security/audit/audit.c
index 517c154..cb5b3fa 100644
--- a/sys/security/audit/audit.c
+++ b/sys/security/audit/audit.c
@@ -69,20 +69,7 @@
 
 #include <vm/uma.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
-
-static uma_zone_t audit_record_zone;
+static uma_zone_t	audit_record_zone;
 static MALLOC_DEFINE(M_AUDITPROC, "audit_proc", "Audit process storage");
 MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage");
 MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage");
@@ -95,37 +82,37 @@ MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage");
 /* 
  * Define the audit control flags.
  */
-int					audit_enabled;
-int					audit_suspended;
+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;
+int				audit_panic_on_write_fail;
+int				audit_fail_stop;
 
 /*
  * Are we currently "failing stop" due to out of disk space?
  */
-static int				 audit_in_failure;
+int				 audit_in_failure;
 
 /*
  * Global audit statistiscs. 
  */
-struct audit_fstat 			audit_fstat;
+struct audit_fstat 		audit_fstat;
 
 /*
  * Preselection mask for non-attributable events.
  */
-struct au_mask			 	audit_nae_mask;
+struct au_mask		 	audit_nae_mask;
 
 /*
  * Mutex to protect global variables shared between various threads and
  * processes.
  */
-static struct mtx			audit_mtx;
+struct mtx			audit_mtx;
 
 /*
  * Queue of audit records ready for delivery to disk.  We insert new
@@ -135,67 +122,37 @@ static struct mtx			audit_mtx;
  * 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;
+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;
+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.
  */
-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;
+struct cv			audit_cv;
 
 /*
  * 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.
+ *
+ * XXXRW: This description is incorrect.
  */
-static struct cv			audit_commit_cv;
+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;
+static struct cv		audit_fail_cv;
 
 /*
  * Construct an audit record for the passed thread.
@@ -253,365 +210,6 @@ audit_record_dtor(void *mem, int size, void *arg)
 }
 
 /*
- * 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;
-
-	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
-	ret = VOP_GETATTR(vp, &vattr, cred, td);
-	VOP_UNLOCK(vp, 0, 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) {
-		(void)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)
-				(void)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;
-		(void)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_record_write: 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) {
-		/*
-		 * Try submitting the record to any active audit pipes.
-		 */
-		audit_pipe_submit((void *)ar->k_udata, ar->k_ulen);
-
-		/*
-		 * And to disk.
-		 */
-		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;
-	}
-
-	/*
-	 * Try submitting the record to any active audit pipes.
-	 */
-	audit_pipe_submit((void *)bsm->data, bsm->len);
-	
-	/*
-	 * 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.
-		 */
-		if (audit_vp == NULL) {
-			while ((ar = TAILQ_FIRST(&audit_q))) {
-				TAILQ_REMOVE(&audit_q, ar, k_q);
-				uma_zfree(audit_record_zone, ar);
-				audit_q_len--;
-				/*
-				 * XXXRW: Why broadcast if we hold the
-				 * mutex and know that audit_vp is NULL?
-				 */
-				if (audit_q_len <= audit_qctrl.aq_lowater)
-					cv_broadcast(&audit_commit_cv);
-			}
-			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.
-		 */
-		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);
-			}
-			uma_zfree(audit_record_zone, 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.
@@ -619,7 +217,6 @@ audit_worker(void *arg)
 static void
 audit_init(void)
 {
-	int error;
 
 	printf("Security auditing service present\n");
 	audit_enabled = 0;
@@ -628,10 +225,6 @@ audit_init(void)
 	audit_fail_stop = 0;
 	audit_in_failure = 0;
 
-	audit_replacement_vp = NULL;
-	audit_replacement_cred = NULL;
-	audit_replacement_flag = 0;
-
 	audit_fstat.af_filesz = 0;	/* '0' means unset, unbounded */
 	audit_fstat.af_currsz = 0; 
 	audit_nae_mask.am_success = AU_NULL;
@@ -647,7 +240,6 @@ audit_init(void)
 
 	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");
 
@@ -658,83 +250,19 @@ audit_init(void)
 	/* Initialize the BSM audit subsystem. */
 	kau_init();
 
-	audit_file_rotate_wait = 0;
 	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);
+	/* Start audit worker thread. */
+	audit_worker_init();
 }
 
 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.
@@ -793,6 +321,13 @@ audit_new(int event, struct thread *td)
 	return (ar);
 }
 
+void
+audit_free(struct kaudit_record *ar)
+{
+
+	uma_zfree(audit_record_zone, ar);
+}
+
 /*
  * MPSAFE
  */