Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit

Pull audit updates from Paul Moore:
 "After the small number of patches for v4.9, we've got a much bigger
  pile for v4.10.

  The bulk of these patches involve a rework of the audit backlog queue
  to enable us to move the netlink multicasting out of the task/thread
  that generates the audit record and into the kernel thread that emits
  the record (just like we do for the audit unicast to auditd).

  While we were playing with the backlog queue(s) we fixed a number of
  other little problems with the code, and from all the testing so far
  things look to be in much better shape now. Doing this also allowed us
  to re-enable disabling IRQs for some netns operations ("netns: avoid
  disabling irq for netns id").

  The remaining patches fix some small problems that are well documented
  in the commit descriptions, as well as adding session ID filtering
  support"

* 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit:
  audit: use proper refcount locking on audit_sock
  netns: avoid disabling irq for netns id
  audit: don't ever sleep on a command record/message
  audit: handle a clean auditd shutdown with grace
  audit: wake up kauditd_thread after auditd registers
  audit: rework audit_log_start()
  audit: rework the audit queue handling
  audit: rename the queues and kauditd related functions
  audit: queue netlink multicast sends just like we do for unicast sends
  audit: fixup audit_init()
  audit: move kaudit thread start from auditd registration to kaudit init (#2)
  audit: add support for session ID user filter
  audit: fix formatting of AUDIT_CONFIG_CHANGE events
  audit: skip sessionid sentinel value when auto-incrementing
  audit: tame initialization warning len_abuf in audit_log_execve_info
  audit: less stack usage for /proc/*/loginuid

fs/proc/base.c

@@ -1246,7 +1246,7 @@ static const struct file_operations proc_oom_score_adj_operations = {
 };
 
 #ifdef CONFIG_AUDITSYSCALL
-#define TMPBUFLEN 21
+#define TMPBUFLEN 11
 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
 				  size_t count, loff_t *ppos)
 {

include/uapi/linux/audit.h

@@ -254,6 +254,7 @@
 #define AUDIT_OBJ_LEV_LOW	22
 #define AUDIT_OBJ_LEV_HIGH	23
 #define AUDIT_LOGINUID_SET	24
+#define AUDIT_SESSIONID	25	/* Session ID */
 
 				/* These are ONLY useful when checking
 				 * at syscall exit time (AUDIT_AT_EXIT). */
@@ -330,10 +331,12 @@ enum {
 #define AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME	0x00000002
 #define AUDIT_FEATURE_BITMAP_EXECUTABLE_PATH	0x00000004
 #define AUDIT_FEATURE_BITMAP_EXCLUDE_EXTEND	0x00000008
+#define AUDIT_FEATURE_BITMAP_SESSIONID_FILTER	0x00000010
 #define AUDIT_FEATURE_BITMAP_ALL (AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT | \
 				  AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME | \
 				  AUDIT_FEATURE_BITMAP_EXECUTABLE_PATH | \
-				  AUDIT_FEATURE_BITMAP_EXCLUDE_EXTEND)
+				  AUDIT_FEATURE_BITMAP_EXCLUDE_EXTEND | \
+				  AUDIT_FEATURE_BITMAP_SESSIONID_FILTER)
 
 /* deprecated: AUDIT_VERSION_* */
 #define AUDIT_VERSION_LATEST 		AUDIT_FEATURE_BITMAP_ALL

kernel/audit.c

@@ -107,7 +107,6 @@ static u32	audit_rate_limit;
  * When set to zero, this means unlimited. */
 static u32	audit_backlog_limit = 64;
 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
-static u32	audit_backlog_wait_time_master = AUDIT_BACKLOG_WAIT_TIME;
 static u32	audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
 
 /* The identity of the user shutting down the audit system. */
@@ -138,11 +137,18 @@ static DEFINE_SPINLOCK(audit_freelist_lock);
 static int	   audit_freelist_count;
 static LIST_HEAD(audit_freelist);
 
-static struct sk_buff_head audit_skb_queue;
-/* queue of skbs to send to auditd when/if it comes back */
-static struct sk_buff_head audit_skb_hold_queue;
+/* queue msgs to send via kauditd_task */
+static struct sk_buff_head audit_queue;
+/* queue msgs due to temporary unicast send problems */
+static struct sk_buff_head audit_retry_queue;
+/* queue msgs waiting for new auditd connection */
+static struct sk_buff_head audit_hold_queue;
+
+/* queue servicing thread */
 static struct task_struct *kauditd_task;
 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
+
+/* waitqueue for callers who are blocked on the audit backlog */
 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
 
 static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
@@ -338,7 +344,7 @@ static int audit_set_backlog_limit(u32 limit)
 static int audit_set_backlog_wait_time(u32 timeout)
 {
 	return audit_do_config_change("audit_backlog_wait_time",
-				      &audit_backlog_wait_time_master, timeout);
+				      &audit_backlog_wait_time, timeout);
 }
 
 static int audit_set_enabled(u32 state)
@@ -364,30 +370,11 @@ static int audit_set_failure(u32 state)
 	return audit_do_config_change("audit_failure", &audit_failure, state);
 }
 
-/*
- * Queue skbs to be sent to auditd when/if it comes back.  These skbs should
- * already have been sent via prink/syslog and so if these messages are dropped
- * it is not a huge concern since we already passed the audit_log_lost()
- * notification and stuff.  This is just nice to get audit messages during
- * boot before auditd is running or messages generated while auditd is stopped.
- * This only holds messages is audit_default is set, aka booting with audit=1
- * or building your kernel that way.
- */
-static void audit_hold_skb(struct sk_buff *skb)
-{
-	if (audit_default &&
-	    (!audit_backlog_limit ||
-	     skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit))
-		skb_queue_tail(&audit_skb_hold_queue, skb);
-	else
-		kfree_skb(skb);
-}
-
 /*
  * For one reason or another this nlh isn't getting delivered to the userspace
  * audit daemon, just send it to printk.
  */
-static void audit_printk_skb(struct sk_buff *skb)
+static void kauditd_printk_skb(struct sk_buff *skb)
 {
 	struct nlmsghdr *nlh = nlmsg_hdr(skb);
 	char *data = nlmsg_data(nlh);
@@ -398,58 +385,123 @@ static void audit_printk_skb(struct sk_buff *skb)
 		else
 			audit_log_lost("printk limit exceeded");
 	}
+}
+
+/**
+ * kauditd_hold_skb - Queue an audit record, waiting for auditd
+ * @skb: audit record
+ *
+ * Description:
+ * Queue the audit record, waiting for an instance of auditd.  When this
+ * function is called we haven't given up yet on sending the record, but things
+ * are not looking good.  The first thing we want to do is try to write the
+ * record via printk and then see if we want to try and hold on to the record
+ * and queue it, if we have room.  If we want to hold on to the record, but we
+ * don't have room, record a record lost message.
+ */
+static void kauditd_hold_skb(struct sk_buff *skb)
+{
+	/* at this point it is uncertain if we will ever send this to auditd so
+	 * try to send the message via printk before we go any further */
+	kauditd_printk_skb(skb);
+
+	/* can we just silently drop the message? */
+	if (!audit_default) {
+		kfree_skb(skb);
+		return;
+	}
+
+	/* if we have room, queue the message */
+	if (!audit_backlog_limit ||
+	    skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
+		skb_queue_tail(&audit_hold_queue, skb);
+		return;
+	}
 
-	audit_hold_skb(skb);
+	/* we have no other options - drop the message */
+	audit_log_lost("kauditd hold queue overflow");
+	kfree_skb(skb);
 }
 
-static void kauditd_send_skb(struct sk_buff *skb)
+/**
+ * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
+ * @skb: audit record
+ *
+ * Description:
+ * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
+ * but for some reason we are having problems sending it audit records so
+ * queue the given record and attempt to resend.
+ */
+static void kauditd_retry_skb(struct sk_buff *skb)
 {
-	int err;
-	int attempts = 0;
-#define AUDITD_RETRIES 5
+	/* NOTE: because records should only live in the retry queue for a
+	 * short period of time, before either being sent or moved to the hold
+	 * queue, we don't currently enforce a limit on this queue */
+	skb_queue_tail(&audit_retry_queue, skb);
+}
+
+/**
+ * auditd_reset - Disconnect the auditd connection
+ *
+ * Description:
+ * Break the auditd/kauditd connection and move all the records in the retry
+ * queue into the hold queue in case auditd reconnects.  The audit_cmd_mutex
+ * must be held when calling this function.
+ */
+static void auditd_reset(void)
+{
+	struct sk_buff *skb;
+
+	/* break the connection */
+	if (audit_sock) {
+		sock_put(audit_sock);
+		audit_sock = NULL;
+	}
+	audit_pid = 0;
+	audit_nlk_portid = 0;
+
+	/* flush all of the retry queue to the hold queue */
+	while ((skb = skb_dequeue(&audit_retry_queue)))
+		kauditd_hold_skb(skb);
+}
+
+/**
+ * kauditd_send_unicast_skb - Send a record via unicast to auditd
+ * @skb: audit record
+ */
+static int kauditd_send_unicast_skb(struct sk_buff *skb)
+{
+	int rc;
 
-restart:
-	/* take a reference in case we can't send it and we want to hold it */
+	/* if we know nothing is connected, don't even try the netlink call */
+	if (!audit_pid)
+		return -ECONNREFUSED;
+
+	/* get an extra skb reference in case we fail to send */
 	skb_get(skb);
-	err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
-	if (err < 0) {
-		pr_err("netlink_unicast sending to audit_pid=%d returned error: %d\n",
-		       audit_pid, err);
-		if (audit_pid) {
-			if (err == -ECONNREFUSED || err == -EPERM
-			    || ++attempts >= AUDITD_RETRIES) {
-				char s[32];
-
-				snprintf(s, sizeof(s), "audit_pid=%d reset", audit_pid);
-				audit_log_lost(s);
-				audit_pid = 0;
-				audit_sock = NULL;
-			} else {
-				pr_warn("re-scheduling(#%d) write to audit_pid=%d\n",
-					attempts, audit_pid);
-				set_current_state(TASK_INTERRUPTIBLE);
-				schedule();
-				goto restart;
-			}
-		}
-		/* we might get lucky and get this in the next auditd */
-		audit_hold_skb(skb);
-	} else
-		/* drop the extra reference if sent ok */
+	rc = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
+	if (rc >= 0) {
 		consume_skb(skb);
+		rc = 0;
+	}
+
+	return rc;
 }
 
 /*
- * kauditd_send_multicast_skb - send the skb to multicast userspace listeners
+ * kauditd_send_multicast_skb - Send a record to any multicast listeners
+ * @skb: audit record
  *
+ * Description:
  * This function doesn't consume an skb as might be expected since it has to
  * copy it anyways.
  */
-static void kauditd_send_multicast_skb(struct sk_buff *skb, gfp_t gfp_mask)
+static void kauditd_send_multicast_skb(struct sk_buff *skb)
 {
-	struct sk_buff		*copy;
-	struct audit_net	*aunet = net_generic(&init_net, audit_net_id);
-	struct sock		*sock = aunet->nlsk;
+	struct sk_buff *copy;
+	struct audit_net *aunet = net_generic(&init_net, audit_net_id);
+	struct sock *sock = aunet->nlsk;
+	struct nlmsghdr *nlh;
 
 	if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
 		return;
@@ -464,74 +516,161 @@ static void kauditd_send_multicast_skb(struct sk_buff *skb, gfp_t gfp_mask)
 	 * no reason for new multicast clients to continue with this
 	 * non-compliance.
 	 */
-	copy = skb_copy(skb, gfp_mask);
+	copy = skb_copy(skb, GFP_KERNEL);
 	if (!copy)
 		return;
+	nlh = nlmsg_hdr(copy);
+	nlh->nlmsg_len = skb->len;
 
-	nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, gfp_mask);
+	nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
 }
 
-/*
- * flush_hold_queue - empty the hold queue if auditd appears
- *
- * If auditd just started, drain the queue of messages already
- * sent to syslog/printk.  Remember loss here is ok.  We already
- * called audit_log_lost() if it didn't go out normally.  so the
- * race between the skb_dequeue and the next check for audit_pid
- * doesn't matter.
+/**
+ * kauditd_wake_condition - Return true when it is time to wake kauditd_thread
  *
- * If you ever find kauditd to be too slow we can get a perf win
- * by doing our own locking and keeping better track if there
- * are messages in this queue.  I don't see the need now, but
- * in 5 years when I want to play with this again I'll see this
- * note and still have no friggin idea what i'm thinking today.
+ * Description:
+ * This function is for use by the wait_event_freezable() call in
+ * kauditd_thread().
  */
-static void flush_hold_queue(void)
+static int kauditd_wake_condition(void)
 {
-	struct sk_buff *skb;
-
-	if (!audit_default || !audit_pid)
-		return;
-
-	skb = skb_dequeue(&audit_skb_hold_queue);
-	if (likely(!skb))
-		return;
+	static int pid_last = 0;
+	int rc;
+	int pid = audit_pid;
 
-	while (skb && audit_pid) {
-		kauditd_send_skb(skb);
-		skb = skb_dequeue(&audit_skb_hold_queue);
-	}
+	/* wake on new messages or a change in the connected auditd */
+	rc = skb_queue_len(&audit_queue) || (pid && pid != pid_last);
+	if (rc)
+		pid_last = pid;
 
-	/*
-	 * if auditd just disappeared but we
-	 * dequeued an skb we need to drop ref
-	 */
-	consume_skb(skb);
+	return rc;
 }
 
 static int kauditd_thread(void *dummy)
 {
+	int rc;
+	int auditd = 0;
+	int reschedule = 0;
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+
+#define UNICAST_RETRIES 5
+#define AUDITD_BAD(x,y) \
+	((x) == -ECONNREFUSED || (x) == -EPERM || ++(y) >= UNICAST_RETRIES)
+
+	/* NOTE: we do invalidate the auditd connection flag on any sending
+	 * errors, but we only "restore" the connection flag at specific places
+	 * in the loop in order to help ensure proper ordering of audit
+	 * records */
+
 	set_freezable();
 	while (!kthread_should_stop()) {
-		struct sk_buff *skb;
-
-		flush_hold_queue();
+		/* NOTE: possible area for future improvement is to look at
+		 *       the hold and retry queues, since only this thread
+		 *       has access to these queues we might be able to do
+		 *       our own queuing and skip some/all of the locking */
+
+		/* NOTE: it might be a fun experiment to split the hold and
+		 *       retry queue handling to another thread, but the
+		 *       synchronization issues and other overhead might kill
+		 *       any performance gains */
+
+		/* attempt to flush the hold queue */
+		while (auditd && (skb = skb_dequeue(&audit_hold_queue))) {
+			rc = kauditd_send_unicast_skb(skb);
+			if (rc) {
+				/* requeue to the same spot */
+				skb_queue_head(&audit_hold_queue, skb);
+
+				auditd = 0;
+				if (AUDITD_BAD(rc, reschedule)) {
+					mutex_lock(&audit_cmd_mutex);
+					auditd_reset();
+					mutex_unlock(&audit_cmd_mutex);
+					reschedule = 0;
+				}
+			} else
+				/* we were able to send successfully */
+				reschedule = 0;
+		}
 
-		skb = skb_dequeue(&audit_skb_queue);
+		/* attempt to flush the retry queue */
+		while (auditd && (skb = skb_dequeue(&audit_retry_queue))) {
+			rc = kauditd_send_unicast_skb(skb);
+			if (rc) {
+				auditd = 0;
+				if (AUDITD_BAD(rc, reschedule)) {
+					kauditd_hold_skb(skb);
+					mutex_lock(&audit_cmd_mutex);
+					auditd_reset();
+					mutex_unlock(&audit_cmd_mutex);
+					reschedule = 0;
+				} else
+					/* temporary problem (we hope), queue
+					 * to the same spot and retry */
+					skb_queue_head(&audit_retry_queue, skb);
+			} else
+				/* we were able to send successfully */
+				reschedule = 0;
+		}
 
+		/* standard queue processing, try to be as quick as possible */
+quick_loop:
+		skb = skb_dequeue(&audit_queue);
 		if (skb) {
-			if (!audit_backlog_limit ||
-			    (skb_queue_len(&audit_skb_queue) <= audit_backlog_limit))
-				wake_up(&audit_backlog_wait);
-			if (audit_pid)
-				kauditd_send_skb(skb);
+			/* setup the netlink header, see the comments in
+			 * kauditd_send_multicast_skb() for length quirks */
+			nlh = nlmsg_hdr(skb);
+			nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
+
+			/* attempt to send to any multicast listeners */
+			kauditd_send_multicast_skb(skb);
+
+			/* attempt to send to auditd, queue on failure */
+			if (auditd) {
+				rc = kauditd_send_unicast_skb(skb);
+				if (rc) {
+					auditd = 0;
+					if (AUDITD_BAD(rc, reschedule)) {
+						mutex_lock(&audit_cmd_mutex);
+						auditd_reset();
+						mutex_unlock(&audit_cmd_mutex);
+						reschedule = 0;
+					}
+
+					/* move to the retry queue */
+					kauditd_retry_skb(skb);
+				} else
+					/* everything is working so go fast! */
+					goto quick_loop;
+			} else if (reschedule)
+				/* we are currently having problems, move to
+				 * the retry queue */
+				kauditd_retry_skb(skb);
 			else
-				audit_printk_skb(skb);
-			continue;
-		}
+				/* dump the message via printk and hold it */
+				kauditd_hold_skb(skb);
+		} else {
+			/* we have flushed the backlog so wake everyone */
+			wake_up(&audit_backlog_wait);
+
+			/* if everything is okay with auditd (if present), go
+			 * to sleep until there is something new in the queue
+			 * or we have a change in the connected auditd;
+			 * otherwise simply reschedule to give things a chance
+			 * to recover */
+			if (reschedule) {
+				set_current_state(TASK_INTERRUPTIBLE);
+				schedule();
+			} else
+				wait_event_freezable(kauditd_wait,
+						     kauditd_wake_condition());
 
-		wait_event_freezable(kauditd_wait, skb_queue_len(&audit_skb_queue));
+			/* update the auditd connection status */
+			auditd = (audit_pid ? 1 : 0);
+		}
 	}
+
 	return 0;
 }
 
@@ -596,6 +735,7 @@ static int audit_send_reply_thread(void *arg)
 	kfree(reply);
 	return 0;
 }
+
 /**
  * audit_send_reply - send an audit reply message via netlink
  * @request_skb: skb of request we are replying to (used to target the reply)
@@ -832,16 +972,6 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	if (err)
 		return err;
 
-	/* As soon as there's any sign of userspace auditd,
-	 * start kauditd to talk to it */
-	if (!kauditd_task) {
-		kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
-		if (IS_ERR(kauditd_task)) {
-			err = PTR_ERR(kauditd_task);
-			kauditd_task = NULL;
-			return err;
-		}
-	}
 	seq  = nlh->nlmsg_seq;
 	data = nlmsg_data(nlh);
 
@@ -855,9 +985,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		s.rate_limit		= audit_rate_limit;
 		s.backlog_limit		= audit_backlog_limit;
 		s.lost			= atomic_read(&audit_lost);
-		s.backlog		= skb_queue_len(&audit_skb_queue);
+		s.backlog		= skb_queue_len(&audit_queue);
 		s.feature_bitmap	= AUDIT_FEATURE_BITMAP_ALL;
-		s.backlog_wait_time	= audit_backlog_wait_time_master;
+		s.backlog_wait_time	= audit_backlog_wait_time;
 		audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
 		break;
 	}
@@ -897,9 +1027,17 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 			}
 			if (audit_enabled != AUDIT_OFF)
 				audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
-			audit_pid = new_pid;
-			audit_nlk_portid = NETLINK_CB(skb).portid;
-			audit_sock = skb->sk;
+			if (new_pid) {
+				if (audit_sock)
+					sock_put(audit_sock);
+				audit_pid = new_pid;
+				audit_nlk_portid = NETLINK_CB(skb).portid;
+				sock_hold(skb->sk);
+				audit_sock = skb->sk;
+			} else {
+				auditd_reset();
+			}
+			wake_up_interruptible(&kauditd_wait);
 		}
 		if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
 			err = audit_set_rate_limit(s.rate_limit);
@@ -1167,10 +1305,10 @@ static void __net_exit audit_net_exit(struct net *net)
 {
 	struct audit_net *aunet = net_generic(net, audit_net_id);
 	struct sock *sock = aunet->nlsk;
-	if (sock == audit_sock) {
-		audit_pid = 0;
-		audit_sock = NULL;
-	}
+	mutex_lock(&audit_cmd_mutex);
+	if (sock == audit_sock)
+		auditd_reset();
+	mutex_unlock(&audit_cmd_mutex);
 
 	netlink_kernel_release(sock);
 	aunet->nlsk = NULL;
@@ -1195,17 +1333,24 @@ static int __init audit_init(void)
 		audit_default ? "enabled" : "disabled");
 	register_pernet_subsys(&audit_net_ops);
 
-	skb_queue_head_init(&audit_skb_queue);
-	skb_queue_head_init(&audit_skb_hold_queue);
+	skb_queue_head_init(&audit_queue);
+	skb_queue_head_init(&audit_retry_queue);
+	skb_queue_head_init(&audit_hold_queue);
 	audit_initialized = AUDIT_INITIALIZED;
 	audit_enabled = audit_default;
 	audit_ever_enabled |= !!audit_default;
 
-	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
-
 	for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
 		INIT_LIST_HEAD(&audit_inode_hash[i]);
 
+	kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
+	if (IS_ERR(kauditd_task)) {
+		int err = PTR_ERR(kauditd_task);
+		panic("audit: failed to start the kauditd thread (%d)\n", err);
+	}
+
+	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
+
 	return 0;
 }
 __initcall(audit_init);
@@ -1338,24 +1483,6 @@ static inline void audit_get_stamp(struct audit_context *ctx,
 	}
 }
 
-/*
- * Wait for auditd to drain the queue a little
- */
-static long wait_for_auditd(long sleep_time)
-{
-	DECLARE_WAITQUEUE(wait, current);
-
-	if (audit_backlog_limit &&
-	    skb_queue_len(&audit_skb_queue) > audit_backlog_limit) {
-		add_wait_queue_exclusive(&audit_backlog_wait, &wait);
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		sleep_time = schedule_timeout(sleep_time);
-		remove_wait_queue(&audit_backlog_wait, &wait);
-	}
-
-	return sleep_time;
-}
-
 /**
  * audit_log_start - obtain an audit buffer
  * @ctx: audit_context (may be NULL)
@@ -1374,12 +1501,9 @@ static long wait_for_auditd(long sleep_time)
 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 				     int type)
 {
-	struct audit_buffer	*ab	= NULL;
-	struct timespec		t;
-	unsigned int		uninitialized_var(serial);
-	int reserve = 5; /* Allow atomic callers to go up to five
-			    entries over the normal backlog limit */
-	unsigned long timeout_start = jiffies;
+	struct audit_buffer *ab;
+	struct timespec t;
+	unsigned int uninitialized_var(serial);
 
 	if (audit_initialized != AUDIT_INITIALIZED)
 		return NULL;
@@ -1387,38 +1511,48 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 	if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE)))
 		return NULL;
 
-	if (gfp_mask & __GFP_DIRECT_RECLAIM) {
-		if (audit_pid && audit_pid == current->tgid)
-			gfp_mask &= ~__GFP_DIRECT_RECLAIM;
-		else
-			reserve = 0;
-	}
-
-	while (audit_backlog_limit
-	       && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
-		if (gfp_mask & __GFP_DIRECT_RECLAIM && audit_backlog_wait_time) {
-			long sleep_time;
+	/* don't ever fail/sleep on these two conditions:
+	 * 1. auditd generated record - since we need auditd to drain the
+	 *    queue; also, when we are checking for auditd, compare PIDs using
+	 *    task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
+	 *    using a PID anchored in the caller's namespace
+	 * 2. audit command message - record types 1000 through 1099 inclusive
+	 *    are command messages/records used to manage the kernel subsystem
+	 *    and the audit userspace, blocking on these messages could cause
+	 *    problems under load so don't do it (note: not all of these
+	 *    command types are valid as record types, but it is quicker to
+	 *    just check two ints than a series of ints in a if/switch stmt) */
+	if (!((audit_pid && audit_pid == task_tgid_vnr(current)) ||
+	      (type >= 1000 && type <= 1099))) {
+		long sleep_time = audit_backlog_wait_time;
+
+		while (audit_backlog_limit &&
+		       (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
+			/* wake kauditd to try and flush the queue */
+			wake_up_interruptible(&kauditd_wait);
 
-			sleep_time = timeout_start + audit_backlog_wait_time - jiffies;
-			if (sleep_time > 0) {
-				sleep_time = wait_for_auditd(sleep_time);
-				if (sleep_time > 0)
-					continue;
+			/* sleep if we are allowed and we haven't exhausted our
+			 * backlog wait limit */
+			if ((gfp_mask & __GFP_DIRECT_RECLAIM) &&
+			    (sleep_time > 0)) {
+				DECLARE_WAITQUEUE(wait, current);
+
+				add_wait_queue_exclusive(&audit_backlog_wait,
+							 &wait);
+				set_current_state(TASK_UNINTERRUPTIBLE);
+				sleep_time = schedule_timeout(sleep_time);
+				remove_wait_queue(&audit_backlog_wait, &wait);
+			} else {
+				if (audit_rate_check() && printk_ratelimit())
+					pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
+						skb_queue_len(&audit_queue),
+						audit_backlog_limit);
+				audit_log_lost("backlog limit exceeded");
+				return NULL;
 			}
 		}
-		if (audit_rate_check() && printk_ratelimit())
-			pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
-				skb_queue_len(&audit_skb_queue),
-				audit_backlog_limit);
-		audit_log_lost("backlog limit exceeded");
-		audit_backlog_wait_time = 0;
-		wake_up(&audit_backlog_wait);
-		return NULL;
 	}
 
-	if (!reserve && !audit_backlog_wait_time)
-		audit_backlog_wait_time = audit_backlog_wait_time_master;
-
 	ab = audit_buffer_alloc(ctx, gfp_mask, type);
 	if (!ab) {
 		audit_log_lost("out of memory in audit_log_start");
@@ -1426,9 +1560,9 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 	}
 
 	audit_get_stamp(ab->ctx, &t, &serial);
-
 	audit_log_format(ab, "audit(%lu.%03lu:%u): ",
 			 t.tv_sec, t.tv_nsec/1000000, serial);
+
 	return ab;
 }
 
@@ -1978,10 +2112,10 @@ void audit_log_link_denied(const char *operation, struct path *link)
  * audit_log_end - end one audit record
  * @ab: the audit_buffer
  *
- * netlink_unicast() cannot be called inside an irq context because it blocks
- * (last arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed
- * on a queue and a tasklet is scheduled to remove them from the queue outside
- * the irq context.  May be called in any context.
+ * We can not do a netlink send inside an irq context because it blocks (last
+ * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
+ * queue and a tasklet is scheduled to remove them from the queue outside the
+ * irq context.  May be called in any context.
  */
 void audit_log_end(struct audit_buffer *ab)
 {
@@ -1990,28 +2124,8 @@ void audit_log_end(struct audit_buffer *ab)
 	if (!audit_rate_check()) {
 		audit_log_lost("rate limit exceeded");
 	} else {
-		struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
-
-		nlh->nlmsg_len = ab->skb->len;
-		kauditd_send_multicast_skb(ab->skb, ab->gfp_mask);
-
-		/*
-		 * The original kaudit unicast socket sends up messages with
-		 * nlmsg_len set to the payload length rather than the entire
-		 * message length.  This breaks the standard set by netlink.
-		 * The existing auditd daemon assumes this breakage.  Fixing
-		 * this would require co-ordinating a change in the established
-		 * protocol between the kaudit kernel subsystem and the auditd
-		 * userspace code.
-		 */
-		nlh->nlmsg_len -= NLMSG_HDRLEN;
-
-		if (audit_pid) {
-			skb_queue_tail(&audit_skb_queue, ab->skb);
-			wake_up_interruptible(&kauditd_wait);
-		} else {
-			audit_printk_skb(ab->skb);
-		}
+		skb_queue_tail(&audit_queue, ab->skb);
+		wake_up_interruptible(&kauditd_wait);
 		ab->skb = NULL;
 	}
 	audit_buffer_free(ab);

kernel/audit_fsnotify.c

@@ -130,10 +130,9 @@ static void audit_mark_log_rule_change(struct audit_fsnotify_mark *audit_mark, c
 	ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE);
 	if (unlikely(!ab))
 		return;
-	audit_log_format(ab, "auid=%u ses=%u op=",
+	audit_log_format(ab, "auid=%u ses=%u op=%s",
 			 from_kuid(&init_user_ns, audit_get_loginuid(current)),
-			 audit_get_sessionid(current));
-	audit_log_string(ab, op);
+			 audit_get_sessionid(current), op);
 	audit_log_format(ab, " path=");
 	audit_log_untrustedstring(ab, audit_mark->path);
 	audit_log_key(ab, rule->filterkey);

kernel/audit_tree.c

@@ -458,8 +458,7 @@ static void audit_tree_log_remove_rule(struct audit_krule *rule)
 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
 	if (unlikely(!ab))
 		return;
-	audit_log_format(ab, "op=");
-	audit_log_string(ab, "remove_rule");
+	audit_log_format(ab, "op=remove_rule");
 	audit_log_format(ab, " dir=");
 	audit_log_untrustedstring(ab, rule->tree->pathname);
 	audit_log_key(ab, rule->filterkey);

kernel/audit_watch.c

@@ -242,10 +242,9 @@ static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watc
 		ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE);
 		if (unlikely(!ab))
 			return;
-		audit_log_format(ab, "auid=%u ses=%u op=",
+		audit_log_format(ab, "auid=%u ses=%u op=%s",
 				 from_kuid(&init_user_ns, audit_get_loginuid(current)),
-				 audit_get_sessionid(current));
-		audit_log_string(ab, op);
+				 audit_get_sessionid(current), op);
 		audit_log_format(ab, " path=");
 		audit_log_untrustedstring(ab, w->path);
 		audit_log_key(ab, r->filterkey);

kernel/auditfilter.c

@@ -363,6 +363,7 @@ static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
 	case AUDIT_EXIT:
 	case AUDIT_SUCCESS:
 	case AUDIT_INODE:
+	case AUDIT_SESSIONID:
 		/* bit ops are only useful on syscall args */
 		if (f->op == Audit_bitmask || f->op == Audit_bittest)
 			return -EINVAL;
@@ -476,6 +477,7 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 			if (!gid_valid(f->gid))
 				goto exit_free;
 			break;
+		case AUDIT_SESSIONID:
 		case AUDIT_ARCH:
 			entry->rule.arch_f = f;
 			break;
@@ -1074,8 +1076,7 @@ static void audit_log_rule_change(char *action, struct audit_krule *rule, int re
 		return;
 	audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
 	audit_log_task_context(ab);
-	audit_log_format(ab, " op=");
-	audit_log_string(ab, action);
+	audit_log_format(ab, " op=%s", action);
 	audit_log_key(ab, rule->filterkey);
 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
 	audit_log_end(ab);

kernel/auditsc.c

@@ -446,6 +446,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 	const struct cred *cred;
 	int i, need_sid = 1;
 	u32 sid;
+	unsigned int sessionid;
 
 	cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
 
@@ -508,6 +509,10 @@ static int audit_filter_rules(struct task_struct *tsk,
 		case AUDIT_FSGID:
 			result = audit_gid_comparator(cred->fsgid, f->op, f->gid);
 			break;
+		case AUDIT_SESSIONID:
+			sessionid = audit_get_sessionid(current);
+			result = audit_comparator(sessionid, f->op, f->val);
+			break;
 		case AUDIT_PERS:
 			result = audit_comparator(tsk->personality, f->op, f->val);
 			break;
@@ -1000,7 +1005,7 @@ static void audit_log_execve_info(struct audit_context *context,
 	long len_rem;
 	long len_full;
 	long len_buf;
-	long len_abuf;
+	long len_abuf = 0;
 	long len_tmp;
 	bool require_data;
 	bool encode;
@@ -2025,8 +2030,11 @@ int audit_set_loginuid(kuid_t loginuid)
 		goto out;
 
 	/* are we setting or clearing? */
-	if (uid_valid(loginuid))
+	if (uid_valid(loginuid)) {
 		sessionid = (unsigned int)atomic_inc_return(&session_id);
+		if (unlikely(sessionid == (unsigned int)-1))
+			sessionid = (unsigned int)atomic_inc_return(&session_id);
+	}
 
 	task->sessionid = sessionid;
 	task->loginuid = loginuid;

net/core/net_namespace.c

@@ -218,16 +218,15 @@ static void rtnl_net_notifyid(struct net *net, int cmd, int id);
  */
 int peernet2id_alloc(struct net *net, struct net *peer)
 {
-	unsigned long flags;
 	bool alloc;
 	int id;
 
 	if (atomic_read(&net->count) == 0)
 		return NETNSA_NSID_NOT_ASSIGNED;
-	spin_lock_irqsave(&net->nsid_lock, flags);
+	spin_lock_bh(&net->nsid_lock);
 	alloc = atomic_read(&peer->count) == 0 ? false : true;
 	id = __peernet2id_alloc(net, peer, &alloc);
-	spin_unlock_irqrestore(&net->nsid_lock, flags);
+	spin_unlock_bh(&net->nsid_lock);
 	if (alloc && id >= 0)
 		rtnl_net_notifyid(net, RTM_NEWNSID, id);
 	return id;
@@ -236,12 +235,11 @@ int peernet2id_alloc(struct net *net, struct net *peer)
 /* This function returns, if assigned, the id of a peer netns. */
 int peernet2id(struct net *net, struct net *peer)
 {
-	unsigned long flags;
 	int id;
 
-	spin_lock_irqsave(&net->nsid_lock, flags);
+	spin_lock_bh(&net->nsid_lock);
 	id = __peernet2id(net, peer);
-	spin_unlock_irqrestore(&net->nsid_lock, flags);
+	spin_unlock_bh(&net->nsid_lock);
 	return id;
 }
 EXPORT_SYMBOL(peernet2id);
@@ -256,18 +254,17 @@ bool peernet_has_id(struct net *net, struct net *peer)
 
 struct net *get_net_ns_by_id(struct net *net, int id)
 {
-	unsigned long flags;
 	struct net *peer;
 
 	if (id < 0)
 		return NULL;
 
 	rcu_read_lock();
-	spin_lock_irqsave(&net->nsid_lock, flags);
+	spin_lock_bh(&net->nsid_lock);
 	peer = idr_find(&net->netns_ids, id);
 	if (peer)
 		get_net(peer);
-	spin_unlock_irqrestore(&net->nsid_lock, flags);
+	spin_unlock_bh(&net->nsid_lock);
 	rcu_read_unlock();
 
 	return peer;
@@ -437,17 +434,17 @@ static void cleanup_net(struct work_struct *work)
 		for_each_net(tmp) {
 			int id;
 
-			spin_lock_irq(&tmp->nsid_lock);
+			spin_lock_bh(&tmp->nsid_lock);
 			id = __peernet2id(tmp, net);
 			if (id >= 0)
 				idr_remove(&tmp->netns_ids, id);
-			spin_unlock_irq(&tmp->nsid_lock);
+			spin_unlock_bh(&tmp->nsid_lock);
 			if (id >= 0)
 				rtnl_net_notifyid(tmp, RTM_DELNSID, id);
 		}
-		spin_lock_irq(&net->nsid_lock);
+		spin_lock_bh(&net->nsid_lock);
 		idr_destroy(&net->netns_ids);
-		spin_unlock_irq(&net->nsid_lock);
+		spin_unlock_bh(&net->nsid_lock);
 
 	}
 	rtnl_unlock();
@@ -576,7 +573,6 @@ static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct net *net = sock_net(skb->sk);
 	struct nlattr *tb[NETNSA_MAX + 1];
-	unsigned long flags;
 	struct net *peer;
 	int nsid, err;
 
@@ -597,15 +593,15 @@ static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh)
 	if (IS_ERR(peer))
 		return PTR_ERR(peer);
 
-	spin_lock_irqsave(&net->nsid_lock, flags);
+	spin_lock_bh(&net->nsid_lock);
 	if (__peernet2id(net, peer) >= 0) {
-		spin_unlock_irqrestore(&net->nsid_lock, flags);
+		spin_unlock_bh(&net->nsid_lock);
 		err = -EEXIST;
 		goto out;
 	}
 
 	err = alloc_netid(net, peer, nsid);
-	spin_unlock_irqrestore(&net->nsid_lock, flags);
+	spin_unlock_bh(&net->nsid_lock);
 	if (err >= 0) {
 		rtnl_net_notifyid(net, RTM_NEWNSID, err);
 		err = 0;
@@ -727,11 +723,10 @@ static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
 		.idx = 0,
 		.s_idx = cb->args[0],
 	};
-	unsigned long flags;
 
-	spin_lock_irqsave(&net->nsid_lock, flags);
+	spin_lock_bh(&net->nsid_lock);
 	idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb);
-	spin_unlock_irqrestore(&net->nsid_lock, flags);
+	spin_unlock_bh(&net->nsid_lock);
 
 	cb->args[0] = net_cb.idx;
 	return skb->len;