Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2463 insertions, 0 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
new file mode 100644
index 000000000..16205dd29
--- /dev/null
+++ b/kernel/audit.c
@@ -0,0 +1,2463 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* audit.c -- Auditing support
+ * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
+ * System-call specific features have moved to auditsc.c
+ *
+ * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
+ * All Rights Reserved.
+ *
+ * Written by Rickard E. (Rik) Faith <faith@redhat.com>
+ *
+ * Goals: 1) Integrate fully with Security Modules.
+ *	  2) Minimal run-time overhead:
+ *	     a) Minimal when syscall auditing is disabled (audit_enable=0).
+ *	     b) Small when syscall auditing is enabled and no audit record
+ *		is generated (defer as much work as possible to record
+ *		generation time):
+ *		i) context is allocated,
+ *		ii) names from getname are stored without a copy, and
+ *		iii) inode information stored from path_lookup.
+ *	  3) Ability to disable syscall auditing at boot time (audit=0).
+ *	  4) Usable by other parts of the kernel (if audit_log* is called,
+ *	     then a syscall record will be generated automatically for the
+ *	     current syscall).
+ *	  5) Netlink interface to user-space.
+ *	  6) Support low-overhead kernel-based filtering to minimize the
+ *	     information that must be passed to user-space.
+ *
+ * Audit userspace, documentation, tests, and bug/issue trackers:
+ * 	https://github.com/linux-audit
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/file.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/mm.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/kthread.h>
+#include <linux/kernel.h>
+#include <linux/syscalls.h>
+#include <linux/spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/mutex.h>
+#include <linux/gfp.h>
+#include <linux/pid.h>
+
+#include <linux/audit.h>
+
+#include <net/sock.h>
+#include <net/netlink.h>
+#include <linux/skbuff.h>
+#include <linux/security.h>
+#include <linux/freezer.h>
+#include <linux/pid_namespace.h>
+#include <net/netns/generic.h>
+
+#include "audit.h"
+
+/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
+ * (Initialization happens after skb_init is called.) */
+#define AUDIT_DISABLED		-1
+#define AUDIT_UNINITIALIZED	0
+#define AUDIT_INITIALIZED	1
+static int	audit_initialized = AUDIT_UNINITIALIZED;
+
+u32		audit_enabled = AUDIT_OFF;
+bool		audit_ever_enabled = !!AUDIT_OFF;
+
+EXPORT_SYMBOL_GPL(audit_enabled);
+
+/* Default state when kernel boots without any parameters. */
+static u32	audit_default = AUDIT_OFF;
+
+/* If auditing cannot proceed, audit_failure selects what happens. */
+static u32	audit_failure = AUDIT_FAIL_PRINTK;
+
+/* private audit network namespace index */
+static unsigned int audit_net_id;
+
+/**
+ * struct audit_net - audit private network namespace data
+ * @sk: communication socket
+ */
+struct audit_net {
+	struct sock *sk;
+};
+
+/**
+ * struct auditd_connection - kernel/auditd connection state
+ * @pid: auditd PID
+ * @portid: netlink portid
+ * @net: the associated network namespace
+ * @rcu: RCU head
+ *
+ * Description:
+ * This struct is RCU protected; you must either hold the RCU lock for reading
+ * or the associated spinlock for writing.
+ */
+struct auditd_connection {
+	struct pid *pid;
+	u32 portid;
+	struct net *net;
+	struct rcu_head rcu;
+};
+static struct auditd_connection __rcu *auditd_conn;
+static DEFINE_SPINLOCK(auditd_conn_lock);
+
+/* If audit_rate_limit is non-zero, limit the rate of sending audit records
+ * to that number per second.  This prevents DoS attacks, but results in
+ * audit records being dropped. */
+static u32	audit_rate_limit;
+
+/* Number of outstanding audit_buffers allowed.
+ * 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 = AUDIT_BACKLOG_WAIT_TIME;
+
+/* The identity of the user shutting down the audit system. */
+static kuid_t		audit_sig_uid = INVALID_UID;
+static pid_t		audit_sig_pid = -1;
+static u32		audit_sig_sid;
+
+/* Records can be lost in several ways:
+   0) [suppressed in audit_alloc]
+   1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
+   2) out of memory in audit_log_move [alloc_skb]
+   3) suppressed due to audit_rate_limit
+   4) suppressed due to audit_backlog_limit
+*/
+static atomic_t	audit_lost = ATOMIC_INIT(0);
+
+/* Monotonically increasing sum of time the kernel has spent
+ * waiting while the backlog limit is exceeded.
+ */
+static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0);
+
+/* Hash for inode-based rules */
+struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
+
+static struct kmem_cache *audit_buffer_cache;
+
+/* 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,
+				   .mask = -1,
+				   .features = 0,
+				   .lock = 0,};
+
+static char *audit_feature_names[2] = {
+	"only_unset_loginuid",
+	"loginuid_immutable",
+};
+
+/**
+ * struct audit_ctl_mutex - serialize requests from userspace
+ * @lock: the mutex used for locking
+ * @owner: the task which owns the lock
+ *
+ * Description:
+ * This is the lock struct used to ensure we only process userspace requests
+ * in an orderly fashion.  We can't simply use a mutex/lock here because we
+ * need to track lock ownership so we don't end up blocking the lock owner in
+ * audit_log_start() or similar.
+ */
+static struct audit_ctl_mutex {
+	struct mutex lock;
+	void *owner;
+} audit_cmd_mutex;
+
+/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
+ * audit records.  Since printk uses a 1024 byte buffer, this buffer
+ * should be at least that large. */
+#define AUDIT_BUFSIZ 1024
+
+/* The audit_buffer is used when formatting an audit record.  The caller
+ * locks briefly to get the record off the freelist or to allocate the
+ * buffer, and locks briefly to send the buffer to the netlink layer or
+ * to place it on a transmit queue.  Multiple audit_buffers can be in
+ * use simultaneously. */
+struct audit_buffer {
+	struct sk_buff       *skb;	/* formatted skb ready to send */
+	struct audit_context *ctx;	/* NULL or associated context */
+	gfp_t		     gfp_mask;
+};
+
+struct audit_reply {
+	__u32 portid;
+	struct net *net;
+	struct sk_buff *skb;
+};
+
+/**
+ * auditd_test_task - Check to see if a given task is an audit daemon
+ * @task: the task to check
+ *
+ * Description:
+ * Return 1 if the task is a registered audit daemon, 0 otherwise.
+ */
+int auditd_test_task(struct task_struct *task)
+{
+	int rc;
+	struct auditd_connection *ac;
+
+	rcu_read_lock();
+	ac = rcu_dereference(auditd_conn);
+	rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
+	rcu_read_unlock();
+
+	return rc;
+}
+
+/**
+ * audit_ctl_lock - Take the audit control lock
+ */
+void audit_ctl_lock(void)
+{
+	mutex_lock(&audit_cmd_mutex.lock);
+	audit_cmd_mutex.owner = current;
+}
+
+/**
+ * audit_ctl_unlock - Drop the audit control lock
+ */
+void audit_ctl_unlock(void)
+{
+	audit_cmd_mutex.owner = NULL;
+	mutex_unlock(&audit_cmd_mutex.lock);
+}
+
+/**
+ * audit_ctl_owner_current - Test to see if the current task owns the lock
+ *
+ * Description:
+ * Return true if the current task owns the audit control lock, false if it
+ * doesn't own the lock.
+ */
+static bool audit_ctl_owner_current(void)
+{
+	return (current == audit_cmd_mutex.owner);
+}
+
+/**
+ * auditd_pid_vnr - Return the auditd PID relative to the namespace
+ *
+ * Description:
+ * Returns the PID in relation to the namespace, 0 on failure.
+ */
+static pid_t auditd_pid_vnr(void)
+{
+	pid_t pid;
+	const struct auditd_connection *ac;
+
+	rcu_read_lock();
+	ac = rcu_dereference(auditd_conn);
+	if (!ac || !ac->pid)
+		pid = 0;
+	else
+		pid = pid_vnr(ac->pid);
+	rcu_read_unlock();
+
+	return pid;
+}
+
+/**
+ * audit_get_sk - Return the audit socket for the given network namespace
+ * @net: the destination network namespace
+ *
+ * Description:
+ * Returns the sock pointer if valid, NULL otherwise.  The caller must ensure
+ * that a reference is held for the network namespace while the sock is in use.
+ */
+static struct sock *audit_get_sk(const struct net *net)
+{
+	struct audit_net *aunet;
+
+	if (!net)
+		return NULL;
+
+	aunet = net_generic(net, audit_net_id);
+	return aunet->sk;
+}
+
+void audit_panic(const char *message)
+{
+	switch (audit_failure) {
+	case AUDIT_FAIL_SILENT:
+		break;
+	case AUDIT_FAIL_PRINTK:
+		if (printk_ratelimit())
+			pr_err("%s\n", message);
+		break;
+	case AUDIT_FAIL_PANIC:
+		panic("audit: %s\n", message);
+		break;
+	}
+}
+
+static inline int audit_rate_check(void)
+{
+	static unsigned long	last_check = 0;
+	static int		messages   = 0;
+	static DEFINE_SPINLOCK(lock);
+	unsigned long		flags;
+	unsigned long		now;
+	int			retval	   = 0;
+
+	if (!audit_rate_limit)
+		return 1;
+
+	spin_lock_irqsave(&lock, flags);
+	if (++messages < audit_rate_limit) {
+		retval = 1;
+	} else {
+		now = jiffies;
+		if (time_after(now, last_check + HZ)) {
+			last_check = now;
+			messages   = 0;
+			retval     = 1;
+		}
+	}
+	spin_unlock_irqrestore(&lock, flags);
+
+	return retval;
+}
+
+/**
+ * audit_log_lost - conditionally log lost audit message event
+ * @message: the message stating reason for lost audit message
+ *
+ * Emit at least 1 message per second, even if audit_rate_check is
+ * throttling.
+ * Always increment the lost messages counter.
+*/
+void audit_log_lost(const char *message)
+{
+	static unsigned long	last_msg = 0;
+	static DEFINE_SPINLOCK(lock);
+	unsigned long		flags;
+	unsigned long		now;
+	int			print;
+
+	atomic_inc(&audit_lost);
+
+	print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
+
+	if (!print) {
+		spin_lock_irqsave(&lock, flags);
+		now = jiffies;
+		if (time_after(now, last_msg + HZ)) {
+			print = 1;
+			last_msg = now;
+		}
+		spin_unlock_irqrestore(&lock, flags);
+	}
+
+	if (print) {
+		if (printk_ratelimit())
+			pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
+				atomic_read(&audit_lost),
+				audit_rate_limit,
+				audit_backlog_limit);
+		audit_panic(message);
+	}
+}
+
+static int audit_log_config_change(char *function_name, u32 new, u32 old,
+				   int allow_changes)
+{
+	struct audit_buffer *ab;
+	int rc = 0;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+	if (unlikely(!ab))
+		return rc;
+	audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
+	audit_log_session_info(ab);
+	rc = audit_log_task_context(ab);
+	if (rc)
+		allow_changes = 0; /* Something weird, deny request */
+	audit_log_format(ab, " res=%d", allow_changes);
+	audit_log_end(ab);
+	return rc;
+}
+
+static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
+{
+	int allow_changes, rc = 0;
+	u32 old = *to_change;
+
+	/* check if we are locked */
+	if (audit_enabled == AUDIT_LOCKED)
+		allow_changes = 0;
+	else
+		allow_changes = 1;
+
+	if (audit_enabled != AUDIT_OFF) {
+		rc = audit_log_config_change(function_name, new, old, allow_changes);
+		if (rc)
+			allow_changes = 0;
+	}
+
+	/* If we are allowed, make the change */
+	if (allow_changes == 1)
+		*to_change = new;
+	/* Not allowed, update reason */
+	else if (rc == 0)
+		rc = -EPERM;
+	return rc;
+}
+
+static int audit_set_rate_limit(u32 limit)
+{
+	return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
+}
+
+static int audit_set_backlog_limit(u32 limit)
+{
+	return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
+}
+
+static int audit_set_backlog_wait_time(u32 timeout)
+{
+	return audit_do_config_change("audit_backlog_wait_time",
+				      &audit_backlog_wait_time, timeout);
+}
+
+static int audit_set_enabled(u32 state)
+{
+	int rc;
+	if (state > AUDIT_LOCKED)
+		return -EINVAL;
+
+	rc =  audit_do_config_change("audit_enabled", &audit_enabled, state);
+	if (!rc)
+		audit_ever_enabled |= !!state;
+
+	return rc;
+}
+
+static int audit_set_failure(u32 state)
+{
+	if (state != AUDIT_FAIL_SILENT
+	    && state != AUDIT_FAIL_PRINTK
+	    && state != AUDIT_FAIL_PANIC)
+		return -EINVAL;
+
+	return audit_do_config_change("audit_failure", &audit_failure, state);
+}
+
+/**
+ * auditd_conn_free - RCU helper to release an auditd connection struct
+ * @rcu: RCU head
+ *
+ * Description:
+ * Drop any references inside the auditd connection tracking struct and free
+ * the memory.
+ */
+static void auditd_conn_free(struct rcu_head *rcu)
+{
+	struct auditd_connection *ac;
+
+	ac = container_of(rcu, struct auditd_connection, rcu);
+	put_pid(ac->pid);
+	put_net(ac->net);
+	kfree(ac);
+}
+
+/**
+ * auditd_set - Set/Reset the auditd connection state
+ * @pid: auditd PID
+ * @portid: auditd netlink portid
+ * @net: auditd network namespace pointer
+ *
+ * Description:
+ * This function will obtain and drop network namespace references as
+ * necessary.  Returns zero on success, negative values on failure.
+ */
+static int auditd_set(struct pid *pid, u32 portid, struct net *net)
+{
+	unsigned long flags;
+	struct auditd_connection *ac_old, *ac_new;
+
+	if (!pid || !net)
+		return -EINVAL;
+
+	ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
+	if (!ac_new)
+		return -ENOMEM;
+	ac_new->pid = get_pid(pid);
+	ac_new->portid = portid;
+	ac_new->net = get_net(net);
+
+	spin_lock_irqsave(&auditd_conn_lock, flags);
+	ac_old = rcu_dereference_protected(auditd_conn,
+					   lockdep_is_held(&auditd_conn_lock));
+	rcu_assign_pointer(auditd_conn, ac_new);
+	spin_unlock_irqrestore(&auditd_conn_lock, flags);
+
+	if (ac_old)
+		call_rcu(&ac_old->rcu, auditd_conn_free);
+
+	return 0;
+}
+
+/**
+ * kauditd_printk_skb - Print the audit record to the ring buffer
+ * @skb: audit record
+ *
+ * Whatever the reason, this packet may not make it to the auditd connection
+ * so write it via printk so the information isn't completely lost.
+ */
+static void kauditd_printk_skb(struct sk_buff *skb)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(skb);
+	char *data = nlmsg_data(nlh);
+
+	if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
+		pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
+}
+
+/**
+ * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
+ * @skb: audit record
+ * @error: error code (unused)
+ *
+ * Description:
+ * This should only be used by the kauditd_thread when it fails to flush the
+ * hold queue.
+ */
+static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
+{
+	/* put the record back in the queue */
+	skb_queue_tail(&audit_hold_queue, skb);
+}
+
+/**
+ * kauditd_hold_skb - Queue an audit record, waiting for auditd
+ * @skb: audit record
+ * @error: error code
+ *
+ * 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, int error)
+{
+	/* 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)
+		goto drop;
+
+	/* the hold queue is only for when the daemon goes away completely,
+	 * not -EAGAIN failures; if we are in a -EAGAIN state requeue the
+	 * record on the retry queue unless it's full, in which case drop it
+	 */
+	if (error == -EAGAIN) {
+		if (!audit_backlog_limit ||
+		    skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
+			skb_queue_tail(&audit_retry_queue, skb);
+			return;
+		}
+		audit_log_lost("kauditd retry queue overflow");
+		goto drop;
+	}
+
+	/* if we have room in the hold queue, queue the message */
+	if (!audit_backlog_limit ||
+	    skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
+		skb_queue_tail(&audit_hold_queue, skb);
+		return;
+	}
+
+	/* we have no other options - drop the message */
+	audit_log_lost("kauditd hold queue overflow");
+drop:
+	kfree_skb(skb);
+}
+
+/**
+ * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
+ * @skb: audit record
+ * @error: error code (unused)
+ *
+ * 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, __always_unused int error)
+{
+	if (!audit_backlog_limit ||
+	    skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
+		skb_queue_tail(&audit_retry_queue, skb);
+		return;
+	}
+
+	/* we have to drop the record, send it via printk as a last effort */
+	kauditd_printk_skb(skb);
+	audit_log_lost("kauditd retry queue overflow");
+	kfree_skb(skb);
+}
+
+/**
+ * auditd_reset - Disconnect the auditd connection
+ * @ac: auditd connection state
+ *
+ * Description:
+ * Break the auditd/kauditd connection and move all the queued records into the
+ * hold queue in case auditd reconnects.  It is important to note that the @ac
+ * pointer should never be dereferenced inside this function as it may be NULL
+ * or invalid, you can only compare the memory address!  If @ac is NULL then
+ * the connection will always be reset.
+ */
+static void auditd_reset(const struct auditd_connection *ac)
+{
+	unsigned long flags;
+	struct sk_buff *skb;
+	struct auditd_connection *ac_old;
+
+	/* if it isn't already broken, break the connection */
+	spin_lock_irqsave(&auditd_conn_lock, flags);
+	ac_old = rcu_dereference_protected(auditd_conn,
+					   lockdep_is_held(&auditd_conn_lock));
+	if (ac && ac != ac_old) {
+		/* someone already registered a new auditd connection */
+		spin_unlock_irqrestore(&auditd_conn_lock, flags);
+		return;
+	}
+	rcu_assign_pointer(auditd_conn, NULL);
+	spin_unlock_irqrestore(&auditd_conn_lock, flags);
+
+	if (ac_old)
+		call_rcu(&ac_old->rcu, auditd_conn_free);
+
+	/* flush the retry queue to the hold queue, but don't touch the main
+	 * queue since we need to process that normally for multicast */
+	while ((skb = skb_dequeue(&audit_retry_queue)))
+		kauditd_hold_skb(skb, -ECONNREFUSED);
+}
+
+/**
+ * auditd_send_unicast_skb - Send a record via unicast to auditd
+ * @skb: audit record
+ *
+ * Description:
+ * Send a skb to the audit daemon, returns positive/zero values on success and
+ * negative values on failure; in all cases the skb will be consumed by this
+ * function.  If the send results in -ECONNREFUSED the connection with auditd
+ * will be reset.  This function may sleep so callers should not hold any locks
+ * where this would cause a problem.
+ */
+static int auditd_send_unicast_skb(struct sk_buff *skb)
+{
+	int rc;
+	u32 portid;
+	struct net *net;
+	struct sock *sk;
+	struct auditd_connection *ac;
+
+	/* NOTE: we can't call netlink_unicast while in the RCU section so
+	 *       take a reference to the network namespace and grab local
+	 *       copies of the namespace, the sock, and the portid; the
+	 *       namespace and sock aren't going to go away while we hold a
+	 *       reference and if the portid does become invalid after the RCU
+	 *       section netlink_unicast() should safely return an error */
+
+	rcu_read_lock();
+	ac = rcu_dereference(auditd_conn);
+	if (!ac) {
+		rcu_read_unlock();
+		kfree_skb(skb);
+		rc = -ECONNREFUSED;
+		goto err;
+	}
+	net = get_net(ac->net);
+	sk = audit_get_sk(net);
+	portid = ac->portid;
+	rcu_read_unlock();
+
+	rc = netlink_unicast(sk, skb, portid, 0);
+	put_net(net);
+	if (rc < 0)
+		goto err;
+
+	return rc;
+
+err:
+	if (ac && rc == -ECONNREFUSED)
+		auditd_reset(ac);
+	return rc;
+}
+
+/**
+ * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
+ * @sk: the sending sock
+ * @portid: the netlink destination
+ * @queue: the skb queue to process
+ * @retry_limit: limit on number of netlink unicast failures
+ * @skb_hook: per-skb hook for additional processing
+ * @err_hook: hook called if the skb fails the netlink unicast send
+ *
+ * Description:
+ * Run through the given queue and attempt to send the audit records to auditd,
+ * returns zero on success, negative values on failure.  It is up to the caller
+ * to ensure that the @sk is valid for the duration of this function.
+ *
+ */
+static int kauditd_send_queue(struct sock *sk, u32 portid,
+			      struct sk_buff_head *queue,
+			      unsigned int retry_limit,
+			      void (*skb_hook)(struct sk_buff *skb),
+			      void (*err_hook)(struct sk_buff *skb, int error))
+{
+	int rc = 0;
+	struct sk_buff *skb = NULL;
+	struct sk_buff *skb_tail;
+	unsigned int failed = 0;
+
+	/* NOTE: kauditd_thread takes care of all our locking, we just use
+	 *       the netlink info passed to us (e.g. sk and portid) */
+
+	skb_tail = skb_peek_tail(queue);
+	while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
+		/* call the skb_hook for each skb we touch */
+		if (skb_hook)
+			(*skb_hook)(skb);
+
+		/* can we send to anyone via unicast? */
+		if (!sk) {
+			if (err_hook)
+				(*err_hook)(skb, -ECONNREFUSED);
+			continue;
+		}
+
+retry:
+		/* grab an extra skb reference in case of error */
+		skb_get(skb);
+		rc = netlink_unicast(sk, skb, portid, 0);
+		if (rc < 0) {
+			/* send failed - try a few times unless fatal error */
+			if (++failed >= retry_limit ||
+			    rc == -ECONNREFUSED || rc == -EPERM) {
+				sk = NULL;
+				if (err_hook)
+					(*err_hook)(skb, rc);
+				if (rc == -EAGAIN)
+					rc = 0;
+				/* continue to drain the queue */
+				continue;
+			} else
+				goto retry;
+		} else {
+			/* skb sent - drop the extra reference and continue */
+			consume_skb(skb);
+			failed = 0;
+		}
+	}
+
+	return (rc >= 0 ? 0 : rc);
+}
+
+/*
+ * kauditd_send_multicast_skb - Send a record to any multicast listeners
+ * @skb: audit record
+ *
+ * Description:
+ * Write a multicast message to anyone listening in the initial network
+ * namespace.  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)
+{
+	struct sk_buff *copy;
+	struct sock *sock = audit_get_sk(&init_net);
+	struct nlmsghdr *nlh;
+
+	/* NOTE: we are not taking an additional reference for init_net since
+	 *       we don't have to worry about it going away */
+
+	if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
+		return;
+
+	/*
+	 * The seemingly wasteful skb_copy() rather than bumping the refcount
+	 * using skb_get() is necessary because non-standard mods are made to
+	 * the skb by the original kaudit unicast socket send routine.  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.  There is
+	 * no reason for new multicast clients to continue with this
+	 * non-compliance.
+	 */
+	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_KERNEL);
+}
+
+/**
+ * kauditd_thread - Worker thread to send audit records to userspace
+ * @dummy: unused
+ */
+static int kauditd_thread(void *dummy)
+{
+	int rc;
+	u32 portid = 0;
+	struct net *net = NULL;
+	struct sock *sk = NULL;
+	struct auditd_connection *ac;
+
+#define UNICAST_RETRIES 5
+
+	set_freezable();
+	while (!kthread_should_stop()) {
+		/* NOTE: see the lock comments in auditd_send_unicast_skb() */
+		rcu_read_lock();
+		ac = rcu_dereference(auditd_conn);
+		if (!ac) {
+			rcu_read_unlock();
+			goto main_queue;
+		}
+		net = get_net(ac->net);
+		sk = audit_get_sk(net);
+		portid = ac->portid;
+		rcu_read_unlock();
+
+		/* attempt to flush the hold queue */
+		rc = kauditd_send_queue(sk, portid,
+					&audit_hold_queue, UNICAST_RETRIES,
+					NULL, kauditd_rehold_skb);
+		if (rc < 0) {
+			sk = NULL;
+			auditd_reset(ac);
+			goto main_queue;
+		}
+
+		/* attempt to flush the retry queue */
+		rc = kauditd_send_queue(sk, portid,
+					&audit_retry_queue, UNICAST_RETRIES,
+					NULL, kauditd_hold_skb);
+		if (rc < 0) {
+			sk = NULL;
+			auditd_reset(ac);
+			goto main_queue;
+		}
+
+main_queue:
+		/* process the main queue - do the multicast send and attempt
+		 * unicast, dump failed record sends to the retry queue; if
+		 * sk == NULL due to previous failures we will just do the
+		 * multicast send and move the record to the hold queue */
+		rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
+					kauditd_send_multicast_skb,
+					(sk ?
+					 kauditd_retry_skb : kauditd_hold_skb));
+		if (ac && rc < 0)
+			auditd_reset(ac);
+		sk = NULL;
+
+		/* drop our netns reference, no auditd sends past this line */
+		if (net) {
+			put_net(net);
+			net = NULL;
+		}
+
+		/* we have processed all the queues so wake everyone */
+		wake_up(&audit_backlog_wait);
+
+		/* NOTE: we want to wake up if there is anything on the queue,
+		 *       regardless of if an auditd is connected, as we need to
+		 *       do the multicast send and rotate records from the
+		 *       main queue to the retry/hold queues */
+		wait_event_freezable(kauditd_wait,
+				     (skb_queue_len(&audit_queue) ? 1 : 0));
+	}
+
+	return 0;
+}
+
+int audit_send_list_thread(void *_dest)
+{
+	struct audit_netlink_list *dest = _dest;
+	struct sk_buff *skb;
+	struct sock *sk = audit_get_sk(dest->net);
+
+	/* wait for parent to finish and send an ACK */
+	audit_ctl_lock();
+	audit_ctl_unlock();
+
+	while ((skb = __skb_dequeue(&dest->q)) != NULL)
+		netlink_unicast(sk, skb, dest->portid, 0);
+
+	put_net(dest->net);
+	kfree(dest);
+
+	return 0;
+}
+
+struct sk_buff *audit_make_reply(int seq, int type, int done,
+				 int multi, const void *payload, int size)
+{
+	struct sk_buff	*skb;
+	struct nlmsghdr	*nlh;
+	void		*data;
+	int		flags = multi ? NLM_F_MULTI : 0;
+	int		t     = done  ? NLMSG_DONE  : type;
+
+	skb = nlmsg_new(size, GFP_KERNEL);
+	if (!skb)
+		return NULL;
+
+	nlh	= nlmsg_put(skb, 0, seq, t, size, flags);
+	if (!nlh)
+		goto out_kfree_skb;
+	data = nlmsg_data(nlh);
+	memcpy(data, payload, size);
+	return skb;
+
+out_kfree_skb:
+	kfree_skb(skb);
+	return NULL;
+}
+
+static void audit_free_reply(struct audit_reply *reply)
+{
+	if (!reply)
+		return;
+
+	kfree_skb(reply->skb);
+	if (reply->net)
+		put_net(reply->net);
+	kfree(reply);
+}
+
+static int audit_send_reply_thread(void *arg)
+{
+	struct audit_reply *reply = (struct audit_reply *)arg;
+
+	audit_ctl_lock();
+	audit_ctl_unlock();
+
+	/* Ignore failure. It'll only happen if the sender goes away,
+	   because our timeout is set to infinite. */
+	netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
+	reply->skb = NULL;
+	audit_free_reply(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)
+ * @seq: sequence number
+ * @type: audit message type
+ * @done: done (last) flag
+ * @multi: multi-part message flag
+ * @payload: payload data
+ * @size: payload size
+ *
+ * Allocates a skb, builds the netlink message, and sends it to the port id.
+ */
+static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
+			     int multi, const void *payload, int size)
+{
+	struct task_struct *tsk;
+	struct audit_reply *reply;
+
+	reply = kzalloc(sizeof(*reply), GFP_KERNEL);
+	if (!reply)
+		return;
+
+	reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
+	if (!reply->skb)
+		goto err;
+	reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
+	reply->portid = NETLINK_CB(request_skb).portid;
+
+	tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
+	if (IS_ERR(tsk))
+		goto err;
+
+	return;
+
+err:
+	audit_free_reply(reply);
+}
+
+/*
+ * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
+ * control messages.
+ */
+static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
+{
+	int err = 0;
+
+	/* Only support initial user namespace for now. */
+	/*
+	 * We return ECONNREFUSED because it tricks userspace into thinking
+	 * that audit was not configured into the kernel.  Lots of users
+	 * configure their PAM stack (because that's what the distro does)
+	 * to reject login if unable to send messages to audit.  If we return
+	 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
+	 * configured in and will let login proceed.  If we return EPERM
+	 * userspace will reject all logins.  This should be removed when we
+	 * support non init namespaces!!
+	 */
+	if (current_user_ns() != &init_user_ns)
+		return -ECONNREFUSED;
+
+	switch (msg_type) {
+	case AUDIT_LIST:
+	case AUDIT_ADD:
+	case AUDIT_DEL:
+		return -EOPNOTSUPP;
+	case AUDIT_GET:
+	case AUDIT_SET:
+	case AUDIT_GET_FEATURE:
+	case AUDIT_SET_FEATURE:
+	case AUDIT_LIST_RULES:
+	case AUDIT_ADD_RULE:
+	case AUDIT_DEL_RULE:
+	case AUDIT_SIGNAL_INFO:
+	case AUDIT_TTY_GET:
+	case AUDIT_TTY_SET:
+	case AUDIT_TRIM:
+	case AUDIT_MAKE_EQUIV:
+		/* Only support auditd and auditctl in initial pid namespace
+		 * for now. */
+		if (task_active_pid_ns(current) != &init_pid_ns)
+			return -EPERM;
+
+		if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
+			err = -EPERM;
+		break;
+	case AUDIT_USER:
+	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
+	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
+		if (!netlink_capable(skb, CAP_AUDIT_WRITE))
+			err = -EPERM;
+		break;
+	default:  /* bad msg */
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+static void audit_log_common_recv_msg(struct audit_context *context,
+					struct audit_buffer **ab, u16 msg_type)
+{
+	uid_t uid = from_kuid(&init_user_ns, current_uid());
+	pid_t pid = task_tgid_nr(current);
+
+	if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
+		*ab = NULL;
+		return;
+	}
+
+	*ab = audit_log_start(context, GFP_KERNEL, msg_type);
+	if (unlikely(!*ab))
+		return;
+	audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
+	audit_log_session_info(*ab);
+	audit_log_task_context(*ab);
+}
+
+static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
+					   u16 msg_type)
+{
+	audit_log_common_recv_msg(NULL, ab, msg_type);
+}
+
+static int is_audit_feature_set(int i)
+{
+	return af.features & AUDIT_FEATURE_TO_MASK(i);
+}
+
+
+static int audit_get_feature(struct sk_buff *skb)
+{
+	u32 seq;
+
+	seq = nlmsg_hdr(skb)->nlmsg_seq;
+
+	audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
+
+	return 0;
+}
+
+static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
+				     u32 old_lock, u32 new_lock, int res)
+{
+	struct audit_buffer *ab;
+
+	if (audit_enabled == AUDIT_OFF)
+		return;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
+	if (!ab)
+		return;
+	audit_log_task_info(ab);
+	audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
+			 audit_feature_names[which], !!old_feature, !!new_feature,
+			 !!old_lock, !!new_lock, res);
+	audit_log_end(ab);
+}
+
+static int audit_set_feature(struct audit_features *uaf)
+{
+	int i;
+
+	BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
+
+	/* if there is ever a version 2 we should handle that here */
+
+	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
+		u32 feature = AUDIT_FEATURE_TO_MASK(i);
+		u32 old_feature, new_feature, old_lock, new_lock;
+
+		/* if we are not changing this feature, move along */
+		if (!(feature & uaf->mask))
+			continue;
+
+		old_feature = af.features & feature;
+		new_feature = uaf->features & feature;
+		new_lock = (uaf->lock | af.lock) & feature;
+		old_lock = af.lock & feature;
+
+		/* are we changing a locked feature? */
+		if (old_lock && (new_feature != old_feature)) {
+			audit_log_feature_change(i, old_feature, new_feature,
+						 old_lock, new_lock, 0);
+			return -EPERM;
+		}
+	}
+	/* nothing invalid, do the changes */
+	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
+		u32 feature = AUDIT_FEATURE_TO_MASK(i);
+		u32 old_feature, new_feature, old_lock, new_lock;
+
+		/* if we are not changing this feature, move along */
+		if (!(feature & uaf->mask))
+			continue;
+
+		old_feature = af.features & feature;
+		new_feature = uaf->features & feature;
+		old_lock = af.lock & feature;
+		new_lock = (uaf->lock | af.lock) & feature;
+
+		if (new_feature != old_feature)
+			audit_log_feature_change(i, old_feature, new_feature,
+						 old_lock, new_lock, 1);
+
+		if (new_feature)
+			af.features |= feature;
+		else
+			af.features &= ~feature;
+		af.lock |= new_lock;
+	}
+
+	return 0;
+}
+
+static int audit_replace(struct pid *pid)
+{
+	pid_t pvnr;
+	struct sk_buff *skb;
+
+	pvnr = pid_vnr(pid);
+	skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
+	if (!skb)
+		return -ENOMEM;
+	return auditd_send_unicast_skb(skb);
+}
+
+static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+	u32			seq;
+	void			*data;
+	int			data_len;
+	int			err;
+	struct audit_buffer	*ab;
+	u16			msg_type = nlh->nlmsg_type;
+	struct audit_sig_info   *sig_data;
+	char			*ctx = NULL;
+	u32			len;
+
+	err = audit_netlink_ok(skb, msg_type);
+	if (err)
+		return err;
+
+	seq  = nlh->nlmsg_seq;
+	data = nlmsg_data(nlh);
+	data_len = nlmsg_len(nlh);
+
+	switch (msg_type) {
+	case AUDIT_GET: {
+		struct audit_status	s;
+		memset(&s, 0, sizeof(s));
+		s.enabled		   = audit_enabled;
+		s.failure		   = audit_failure;
+		/* NOTE: use pid_vnr() so the PID is relative to the current
+		 *       namespace */
+		s.pid			   = auditd_pid_vnr();
+		s.rate_limit		   = audit_rate_limit;
+		s.backlog_limit		   = audit_backlog_limit;
+		s.lost			   = atomic_read(&audit_lost);
+		s.backlog		   = skb_queue_len(&audit_queue);
+		s.feature_bitmap	   = AUDIT_FEATURE_BITMAP_ALL;
+		s.backlog_wait_time	   = audit_backlog_wait_time;
+		s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
+		audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
+		break;
+	}
+	case AUDIT_SET: {
+		struct audit_status	s;
+		memset(&s, 0, sizeof(s));
+		/* guard against past and future API changes */
+		memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
+		if (s.mask & AUDIT_STATUS_ENABLED) {
+			err = audit_set_enabled(s.enabled);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask & AUDIT_STATUS_FAILURE) {
+			err = audit_set_failure(s.failure);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask & AUDIT_STATUS_PID) {
+			/* NOTE: we are using the vnr PID functions below
+			 *       because the s.pid value is relative to the
+			 *       namespace of the caller; at present this
+			 *       doesn't matter much since you can really only
+			 *       run auditd from the initial pid namespace, but
+			 *       something to keep in mind if this changes */
+			pid_t new_pid = s.pid;
+			pid_t auditd_pid;
+			struct pid *req_pid = task_tgid(current);
+
+			/* Sanity check - PID values must match. Setting
+			 * pid to 0 is how auditd ends auditing. */
+			if (new_pid && (new_pid != pid_vnr(req_pid)))
+				return -EINVAL;
+
+			/* test the auditd connection */
+			audit_replace(req_pid);
+
+			auditd_pid = auditd_pid_vnr();
+			if (auditd_pid) {
+				/* replacing a healthy auditd is not allowed */
+				if (new_pid) {
+					audit_log_config_change("audit_pid",
+							new_pid, auditd_pid, 0);
+					return -EEXIST;
+				}
+				/* only current auditd can unregister itself */
+				if (pid_vnr(req_pid) != auditd_pid) {
+					audit_log_config_change("audit_pid",
+							new_pid, auditd_pid, 0);
+					return -EACCES;
+				}
+			}
+
+			if (new_pid) {
+				/* register a new auditd connection */
+				err = auditd_set(req_pid,
+						 NETLINK_CB(skb).portid,
+						 sock_net(NETLINK_CB(skb).sk));
+				if (audit_enabled != AUDIT_OFF)
+					audit_log_config_change("audit_pid",
+								new_pid,
+								auditd_pid,
+								err ? 0 : 1);
+				if (err)
+					return err;
+
+				/* try to process any backlog */
+				wake_up_interruptible(&kauditd_wait);
+			} else {
+				if (audit_enabled != AUDIT_OFF)
+					audit_log_config_change("audit_pid",
+								new_pid,
+								auditd_pid, 1);
+
+				/* unregister the auditd connection */
+				auditd_reset(NULL);
+			}
+		}
+		if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
+			err = audit_set_rate_limit(s.rate_limit);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
+			err = audit_set_backlog_limit(s.backlog_limit);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
+			if (sizeof(s) > (size_t)nlh->nlmsg_len)
+				return -EINVAL;
+			if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
+				return -EINVAL;
+			err = audit_set_backlog_wait_time(s.backlog_wait_time);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask == AUDIT_STATUS_LOST) {
+			u32 lost = atomic_xchg(&audit_lost, 0);
+
+			audit_log_config_change("lost", 0, lost, 1);
+			return lost;
+		}
+		if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
+			u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
+
+			audit_log_config_change("backlog_wait_time_actual", 0, actual, 1);
+			return actual;
+		}
+		break;
+	}
+	case AUDIT_GET_FEATURE:
+		err = audit_get_feature(skb);
+		if (err)
+			return err;
+		break;
+	case AUDIT_SET_FEATURE:
+		if (data_len < sizeof(struct audit_features))
+			return -EINVAL;
+		err = audit_set_feature(data);
+		if (err)
+			return err;
+		break;
+	case AUDIT_USER:
+	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
+	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
+		if (!audit_enabled && msg_type != AUDIT_USER_AVC)
+			return 0;
+		/* exit early if there isn't at least one character to print */
+		if (data_len < 2)
+			return -EINVAL;
+
+		err = audit_filter(msg_type, AUDIT_FILTER_USER);
+		if (err == 1) { /* match or error */
+			char *str = data;
+
+			err = 0;
+			if (msg_type == AUDIT_USER_TTY) {
+				err = tty_audit_push();
+				if (err)
+					break;
+			}
+			audit_log_user_recv_msg(&ab, msg_type);
+			if (msg_type != AUDIT_USER_TTY) {
+				/* ensure NULL termination */
+				str[data_len - 1] = '\0';
+				audit_log_format(ab, " msg='%.*s'",
+						 AUDIT_MESSAGE_TEXT_MAX,
+						 str);
+			} else {
+				audit_log_format(ab, " data=");
+				if (str[data_len - 1] == '\0')
+					data_len--;
+				audit_log_n_untrustedstring(ab, str, data_len);
+			}
+			audit_log_end(ab);
+		}
+		break;
+	case AUDIT_ADD_RULE:
+	case AUDIT_DEL_RULE:
+		if (data_len < sizeof(struct audit_rule_data))
+			return -EINVAL;
+		if (audit_enabled == AUDIT_LOCKED) {
+			audit_log_common_recv_msg(audit_context(), &ab,
+						  AUDIT_CONFIG_CHANGE);
+			audit_log_format(ab, " op=%s audit_enabled=%d res=0",
+					 msg_type == AUDIT_ADD_RULE ?
+						"add_rule" : "remove_rule",
+					 audit_enabled);
+			audit_log_end(ab);
+			return -EPERM;
+		}
+		err = audit_rule_change(msg_type, seq, data, data_len);
+		break;
+	case AUDIT_LIST_RULES:
+		err = audit_list_rules_send(skb, seq);
+		break;
+	case AUDIT_TRIM:
+		audit_trim_trees();
+		audit_log_common_recv_msg(audit_context(), &ab,
+					  AUDIT_CONFIG_CHANGE);
+		audit_log_format(ab, " op=trim res=1");
+		audit_log_end(ab);
+		break;
+	case AUDIT_MAKE_EQUIV: {
+		void *bufp = data;
+		u32 sizes[2];
+		size_t msglen = data_len;
+		char *old, *new;
+
+		err = -EINVAL;
+		if (msglen < 2 * sizeof(u32))
+			break;
+		memcpy(sizes, bufp, 2 * sizeof(u32));
+		bufp += 2 * sizeof(u32);
+		msglen -= 2 * sizeof(u32);
+		old = audit_unpack_string(&bufp, &msglen, sizes[0]);
+		if (IS_ERR(old)) {
+			err = PTR_ERR(old);
+			break;
+		}
+		new = audit_unpack_string(&bufp, &msglen, sizes[1]);
+		if (IS_ERR(new)) {
+			err = PTR_ERR(new);
+			kfree(old);
+			break;
+		}
+		/* OK, here comes... */
+		err = audit_tag_tree(old, new);
+
+		audit_log_common_recv_msg(audit_context(), &ab,
+					  AUDIT_CONFIG_CHANGE);
+		audit_log_format(ab, " op=make_equiv old=");
+		audit_log_untrustedstring(ab, old);
+		audit_log_format(ab, " new=");
+		audit_log_untrustedstring(ab, new);
+		audit_log_format(ab, " res=%d", !err);
+		audit_log_end(ab);
+		kfree(old);
+		kfree(new);
+		break;
+	}
+	case AUDIT_SIGNAL_INFO:
+		len = 0;
+		if (audit_sig_sid) {
+			err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
+			if (err)
+				return err;
+		}
+		sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL);
+		if (!sig_data) {
+			if (audit_sig_sid)
+				security_release_secctx(ctx, len);
+			return -ENOMEM;
+		}
+		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
+		sig_data->pid = audit_sig_pid;
+		if (audit_sig_sid) {
+			memcpy(sig_data->ctx, ctx, len);
+			security_release_secctx(ctx, len);
+		}
+		audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
+				 sig_data, struct_size(sig_data, ctx, len));
+		kfree(sig_data);
+		break;
+	case AUDIT_TTY_GET: {
+		struct audit_tty_status s;
+		unsigned int t;
+
+		t = READ_ONCE(current->signal->audit_tty);
+		s.enabled = t & AUDIT_TTY_ENABLE;
+		s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
+
+		audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
+		break;
+	}
+	case AUDIT_TTY_SET: {
+		struct audit_tty_status s, old;
+		struct audit_buffer	*ab;
+		unsigned int t;
+
+		memset(&s, 0, sizeof(s));
+		/* guard against past and future API changes */
+		memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
+		/* check if new data is valid */
+		if ((s.enabled != 0 && s.enabled != 1) ||
+		    (s.log_passwd != 0 && s.log_passwd != 1))
+			err = -EINVAL;
+
+		if (err)
+			t = READ_ONCE(current->signal->audit_tty);
+		else {
+			t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
+			t = xchg(&current->signal->audit_tty, t);
+		}
+		old.enabled = t & AUDIT_TTY_ENABLE;
+		old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
+
+		audit_log_common_recv_msg(audit_context(), &ab,
+					  AUDIT_CONFIG_CHANGE);
+		audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
+				 " old-log_passwd=%d new-log_passwd=%d res=%d",
+				 old.enabled, s.enabled, old.log_passwd,
+				 s.log_passwd, !err);
+		audit_log_end(ab);
+		break;
+	}
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err < 0 ? err : 0;
+}
+
+/**
+ * audit_receive - receive messages from a netlink control socket
+ * @skb: the message buffer
+ *
+ * Parse the provided skb and deal with any messages that may be present,
+ * malformed skbs are discarded.
+ */
+static void audit_receive(struct sk_buff  *skb)
+{
+	struct nlmsghdr *nlh;
+	/*
+	 * len MUST be signed for nlmsg_next to be able to dec it below 0
+	 * if the nlmsg_len was not aligned
+	 */
+	int len;
+	int err;
+
+	nlh = nlmsg_hdr(skb);
+	len = skb->len;
+
+	audit_ctl_lock();
+	while (nlmsg_ok(nlh, len)) {
+		err = audit_receive_msg(skb, nlh);
+		/* if err or if this message says it wants a response */
+		if (err || (nlh->nlmsg_flags & NLM_F_ACK))
+			netlink_ack(skb, nlh, err, NULL);
+
+		nlh = nlmsg_next(nlh, &len);
+	}
+	audit_ctl_unlock();
+
+	/* can't block with the ctrl lock, so penalize the sender now */
+	if (audit_backlog_limit &&
+	    (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
+		DECLARE_WAITQUEUE(wait, current);
+
+		/* wake kauditd to try and flush the queue */
+		wake_up_interruptible(&kauditd_wait);
+
+		add_wait_queue_exclusive(&audit_backlog_wait, &wait);
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(audit_backlog_wait_time);
+		remove_wait_queue(&audit_backlog_wait, &wait);
+	}
+}
+
+/* Log information about who is connecting to the audit multicast socket */
+static void audit_log_multicast(int group, const char *op, int err)
+{
+	const struct cred *cred;
+	struct tty_struct *tty;
+	char comm[sizeof(current->comm)];
+	struct audit_buffer *ab;
+
+	if (!audit_enabled)
+		return;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
+	if (!ab)
+		return;
+
+	cred = current_cred();
+	tty = audit_get_tty();
+	audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
+			 task_pid_nr(current),
+			 from_kuid(&init_user_ns, cred->uid),
+			 from_kuid(&init_user_ns, audit_get_loginuid(current)),
+			 tty ? tty_name(tty) : "(none)",
+			 audit_get_sessionid(current));
+	audit_put_tty(tty);
+	audit_log_task_context(ab); /* subj= */
+	audit_log_format(ab, " comm=");
+	audit_log_untrustedstring(ab, get_task_comm(comm, current));
+	audit_log_d_path_exe(ab, current->mm); /* exe= */
+	audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
+	audit_log_end(ab);
+}
+
+/* Run custom bind function on netlink socket group connect or bind requests. */
+static int audit_multicast_bind(struct net *net, int group)
+{
+	int err = 0;
+
+	if (!capable(CAP_AUDIT_READ))
+		err = -EPERM;
+	audit_log_multicast(group, "connect", err);
+	return err;
+}
+
+static void audit_multicast_unbind(struct net *net, int group)
+{
+	audit_log_multicast(group, "disconnect", 0);
+}
+
+static int __net_init audit_net_init(struct net *net)
+{
+	struct netlink_kernel_cfg cfg = {
+		.input	= audit_receive,
+		.bind	= audit_multicast_bind,
+		.unbind	= audit_multicast_unbind,
+		.flags	= NL_CFG_F_NONROOT_RECV,
+		.groups	= AUDIT_NLGRP_MAX,
+	};
+
+	struct audit_net *aunet = net_generic(net, audit_net_id);
+
+	aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
+	if (aunet->sk == NULL) {
+		audit_panic("cannot initialize netlink socket in namespace");
+		return -ENOMEM;
+	}
+	/* limit the timeout in case auditd is blocked/stopped */
+	aunet->sk->sk_sndtimeo = HZ / 10;
+
+	return 0;
+}
+
+static void __net_exit audit_net_exit(struct net *net)
+{
+	struct audit_net *aunet = net_generic(net, audit_net_id);
+
+	/* NOTE: you would think that we would want to check the auditd
+	 * connection and potentially reset it here if it lives in this
+	 * namespace, but since the auditd connection tracking struct holds a
+	 * reference to this namespace (see auditd_set()) we are only ever
+	 * going to get here after that connection has been released */
+
+	netlink_kernel_release(aunet->sk);
+}
+
+static struct pernet_operations audit_net_ops __net_initdata = {
+	.init = audit_net_init,
+	.exit = audit_net_exit,
+	.id = &audit_net_id,
+	.size = sizeof(struct audit_net),
+};
+
+/* Initialize audit support at boot time. */
+static int __init audit_init(void)
+{
+	int i;
+
+	if (audit_initialized == AUDIT_DISABLED)
+		return 0;
+
+	audit_buffer_cache = kmem_cache_create("audit_buffer",
+					       sizeof(struct audit_buffer),
+					       0, SLAB_PANIC, NULL);
+
+	skb_queue_head_init(&audit_queue);
+	skb_queue_head_init(&audit_retry_queue);
+	skb_queue_head_init(&audit_hold_queue);
+
+	for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
+		INIT_LIST_HEAD(&audit_inode_hash[i]);
+
+	mutex_init(&audit_cmd_mutex.lock);
+	audit_cmd_mutex.owner = NULL;
+
+	pr_info("initializing netlink subsys (%s)\n",
+		audit_default ? "enabled" : "disabled");
+	register_pernet_subsys(&audit_net_ops);
+
+	audit_initialized = AUDIT_INITIALIZED;
+
+	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,
+		"state=initialized audit_enabled=%u res=1",
+		 audit_enabled);
+
+	return 0;
+}
+postcore_initcall(audit_init);
+
+/*
+ * Process kernel command-line parameter at boot time.
+ * audit={0|off} or audit={1|on}.
+ */
+static int __init audit_enable(char *str)
+{
+	if (!strcasecmp(str, "off") || !strcmp(str, "0"))
+		audit_default = AUDIT_OFF;
+	else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
+		audit_default = AUDIT_ON;
+	else {
+		pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
+		audit_default = AUDIT_ON;
+	}
+
+	if (audit_default == AUDIT_OFF)
+		audit_initialized = AUDIT_DISABLED;
+	if (audit_set_enabled(audit_default))
+		pr_err("audit: error setting audit state (%d)\n",
+		       audit_default);
+
+	pr_info("%s\n", audit_default ?
+		"enabled (after initialization)" : "disabled (until reboot)");
+
+	return 1;
+}
+__setup("audit=", audit_enable);
+
+/* Process kernel command-line parameter at boot time.
+ * audit_backlog_limit=<n> */
+static int __init audit_backlog_limit_set(char *str)
+{
+	u32 audit_backlog_limit_arg;
+
+	pr_info("audit_backlog_limit: ");
+	if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
+		pr_cont("using default of %u, unable to parse %s\n",
+			audit_backlog_limit, str);
+		return 1;
+	}
+
+	audit_backlog_limit = audit_backlog_limit_arg;
+	pr_cont("%d\n", audit_backlog_limit);
+
+	return 1;
+}
+__setup("audit_backlog_limit=", audit_backlog_limit_set);
+
+static void audit_buffer_free(struct audit_buffer *ab)
+{
+	if (!ab)
+		return;
+
+	kfree_skb(ab->skb);
+	kmem_cache_free(audit_buffer_cache, ab);
+}
+
+static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
+					       gfp_t gfp_mask, int type)
+{
+	struct audit_buffer *ab;
+
+	ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
+	if (!ab)
+		return NULL;
+
+	ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
+	if (!ab->skb)
+		goto err;
+	if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
+		goto err;
+
+	ab->ctx = ctx;
+	ab->gfp_mask = gfp_mask;
+
+	return ab;
+
+err:
+	audit_buffer_free(ab);
+	return NULL;
+}
+
+/**
+ * audit_serial - compute a serial number for the audit record
+ *
+ * Compute a serial number for the audit record.  Audit records are
+ * written to user-space as soon as they are generated, so a complete
+ * audit record may be written in several pieces.  The timestamp of the
+ * record and this serial number are used by the user-space tools to
+ * determine which pieces belong to the same audit record.  The
+ * (timestamp,serial) tuple is unique for each syscall and is live from
+ * syscall entry to syscall exit.
+ *
+ * NOTE: Another possibility is to store the formatted records off the
+ * audit context (for those records that have a context), and emit them
+ * all at syscall exit.  However, this could delay the reporting of
+ * significant errors until syscall exit (or never, if the system
+ * halts).
+ */
+unsigned int audit_serial(void)
+{
+	static atomic_t serial = ATOMIC_INIT(0);
+
+	return atomic_inc_return(&serial);
+}
+
+static inline void audit_get_stamp(struct audit_context *ctx,
+				   struct timespec64 *t, unsigned int *serial)
+{
+	if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
+		ktime_get_coarse_real_ts64(t);
+		*serial = audit_serial();
+	}
+}
+
+/**
+ * audit_log_start - obtain an audit buffer
+ * @ctx: audit_context (may be NULL)
+ * @gfp_mask: type of allocation
+ * @type: audit message type
+ *
+ * Returns audit_buffer pointer on success or NULL on error.
+ *
+ * Obtain an audit buffer.  This routine does locking to obtain the
+ * audit buffer, but then no locking is required for calls to
+ * audit_log_*format.  If the task (ctx) is a task that is currently in a
+ * syscall, then the syscall is marked as auditable and an audit record
+ * will be written at syscall exit.  If there is no associated task, then
+ * task context (ctx) should be NULL.
+ */
+struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
+				     int type)
+{
+	struct audit_buffer *ab;
+	struct timespec64 t;
+	unsigned int serial;
+
+	if (audit_initialized != AUDIT_INITIALIZED)
+		return NULL;
+
+	if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
+		return NULL;
+
+	/* NOTE: 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. generator holding the audit_cmd_mutex - we don't want to block
+	 *    while holding the mutex, although we do penalize the sender
+	 *    later in audit_receive() when it is safe to block
+	 */
+	if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
+		long stime = 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 if we are allowed and we haven't exhausted our
+			 * backlog wait limit */
+			if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
+				long rtime = stime;
+
+				DECLARE_WAITQUEUE(wait, current);
+
+				add_wait_queue_exclusive(&audit_backlog_wait,
+							 &wait);
+				set_current_state(TASK_UNINTERRUPTIBLE);
+				stime = schedule_timeout(rtime);
+				atomic_add(rtime - stime, &audit_backlog_wait_time_actual);
+				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;
+			}
+		}
+	}
+
+	ab = audit_buffer_alloc(ctx, gfp_mask, type);
+	if (!ab) {
+		audit_log_lost("out of memory in audit_log_start");
+		return NULL;
+	}
+
+	audit_get_stamp(ab->ctx, &t, &serial);
+	/* cancel dummy context to enable supporting records */
+	if (ctx)
+		ctx->dummy = 0;
+	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
+			 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
+
+	return ab;
+}
+
+/**
+ * audit_expand - expand skb in the audit buffer
+ * @ab: audit_buffer
+ * @extra: space to add at tail of the skb
+ *
+ * Returns 0 (no space) on failed expansion, or available space if
+ * successful.
+ */
+static inline int audit_expand(struct audit_buffer *ab, int extra)
+{
+	struct sk_buff *skb = ab->skb;
+	int oldtail = skb_tailroom(skb);
+	int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
+	int newtail = skb_tailroom(skb);
+
+	if (ret < 0) {
+		audit_log_lost("out of memory in audit_expand");
+		return 0;
+	}
+
+	skb->truesize += newtail - oldtail;
+	return newtail;
+}
+
+/*
+ * Format an audit message into the audit buffer.  If there isn't enough
+ * room in the audit buffer, more room will be allocated and vsnprint
+ * will be called a second time.  Currently, we assume that a printk
+ * can't format message larger than 1024 bytes, so we don't either.
+ */
+static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
+			      va_list args)
+{
+	int len, avail;
+	struct sk_buff *skb;
+	va_list args2;
+
+	if (!ab)
+		return;
+
+	BUG_ON(!ab->skb);
+	skb = ab->skb;
+	avail = skb_tailroom(skb);
+	if (avail == 0) {
+		avail = audit_expand(ab, AUDIT_BUFSIZ);
+		if (!avail)
+			goto out;
+	}
+	va_copy(args2, args);
+	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
+	if (len >= avail) {
+		/* The printk buffer is 1024 bytes long, so if we get
+		 * here and AUDIT_BUFSIZ is at least 1024, then we can
+		 * log everything that printk could have logged. */
+		avail = audit_expand(ab,
+			max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
+		if (!avail)
+			goto out_va_end;
+		len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
+	}
+	if (len > 0)
+		skb_put(skb, len);
+out_va_end:
+	va_end(args2);
+out:
+	return;
+}
+
+/**
+ * audit_log_format - format a message into the audit buffer.
+ * @ab: audit_buffer
+ * @fmt: format string
+ * @...: optional parameters matching @fmt string
+ *
+ * All the work is done in audit_log_vformat.
+ */
+void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
+{
+	va_list args;
+
+	if (!ab)
+		return;
+	va_start(args, fmt);
+	audit_log_vformat(ab, fmt, args);
+	va_end(args);
+}
+
+/**
+ * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
+ * @ab: the audit_buffer
+ * @buf: buffer to convert to hex
+ * @len: length of @buf to be converted
+ *
+ * No return value; failure to expand is silently ignored.
+ *
+ * This function will take the passed buf and convert it into a string of
+ * ascii hex digits. The new string is placed onto the skb.
+ */
+void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
+		size_t len)
+{
+	int i, avail, new_len;
+	unsigned char *ptr;
+	struct sk_buff *skb;
+
+	if (!ab)
+		return;
+
+	BUG_ON(!ab->skb);
+	skb = ab->skb;
+	avail = skb_tailroom(skb);
+	new_len = len<<1;
+	if (new_len >= avail) {
+		/* Round the buffer request up to the next multiple */
+		new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
+		avail = audit_expand(ab, new_len);
+		if (!avail)
+			return;
+	}
+
+	ptr = skb_tail_pointer(skb);
+	for (i = 0; i < len; i++)
+		ptr = hex_byte_pack_upper(ptr, buf[i]);
+	*ptr = 0;
+	skb_put(skb, len << 1); /* new string is twice the old string */
+}
+
+/*
+ * Format a string of no more than slen characters into the audit buffer,
+ * enclosed in quote marks.
+ */
+void audit_log_n_string(struct audit_buffer *ab, const char *string,
+			size_t slen)
+{
+	int avail, new_len;
+	unsigned char *ptr;
+	struct sk_buff *skb;
+
+	if (!ab)
+		return;
+
+	BUG_ON(!ab->skb);
+	skb = ab->skb;
+	avail = skb_tailroom(skb);
+	new_len = slen + 3;	/* enclosing quotes + null terminator */
+	if (new_len > avail) {
+		avail = audit_expand(ab, new_len);
+		if (!avail)
+			return;
+	}
+	ptr = skb_tail_pointer(skb);
+	*ptr++ = '"';
+	memcpy(ptr, string, slen);
+	ptr += slen;
+	*ptr++ = '"';
+	*ptr = 0;
+	skb_put(skb, slen + 2);	/* don't include null terminator */
+}
+
+/**
+ * audit_string_contains_control - does a string need to be logged in hex
+ * @string: string to be checked
+ * @len: max length of the string to check
+ */
+bool audit_string_contains_control(const char *string, size_t len)
+{
+	const unsigned char *p;
+	for (p = string; p < (const unsigned char *)string + len; p++) {
+		if (*p == '"' || *p < 0x21 || *p > 0x7e)
+			return true;
+	}
+	return false;
+}
+
+/**
+ * audit_log_n_untrustedstring - log a string that may contain random characters
+ * @ab: audit_buffer
+ * @len: length of string (not including trailing null)
+ * @string: string to be logged
+ *
+ * This code will escape a string that is passed to it if the string
+ * contains a control character, unprintable character, double quote mark,
+ * or a space. Unescaped strings will start and end with a double quote mark.
+ * Strings that are escaped are printed in hex (2 digits per char).
+ *
+ * The caller specifies the number of characters in the string to log, which may
+ * or may not be the entire string.
+ */
+void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
+				 size_t len)
+{
+	if (audit_string_contains_control(string, len))
+		audit_log_n_hex(ab, string, len);
+	else
+		audit_log_n_string(ab, string, len);
+}
+
+/**
+ * audit_log_untrustedstring - log a string that may contain random characters
+ * @ab: audit_buffer
+ * @string: string to be logged
+ *
+ * Same as audit_log_n_untrustedstring(), except that strlen is used to
+ * determine string length.
+ */
+void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
+{
+	audit_log_n_untrustedstring(ab, string, strlen(string));
+}
+
+/* This is a helper-function to print the escaped d_path */
+void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
+		      const struct path *path)
+{
+	char *p, *pathname;
+
+	if (prefix)
+		audit_log_format(ab, "%s", prefix);
+
+	/* We will allow 11 spaces for ' (deleted)' to be appended */
+	pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
+	if (!pathname) {
+		audit_log_format(ab, "\"<no_memory>\"");
+		return;
+	}
+	p = d_path(path, pathname, PATH_MAX+11);
+	if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
+		/* FIXME: can we save some information here? */
+		audit_log_format(ab, "\"<too_long>\"");
+	} else
+		audit_log_untrustedstring(ab, p);
+	kfree(pathname);
+}
+
+void audit_log_session_info(struct audit_buffer *ab)
+{
+	unsigned int sessionid = audit_get_sessionid(current);
+	uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
+
+	audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
+}
+
+void audit_log_key(struct audit_buffer *ab, char *key)
+{
+	audit_log_format(ab, " key=");
+	if (key)
+		audit_log_untrustedstring(ab, key);
+	else
+		audit_log_format(ab, "(null)");
+}
+
+int audit_log_task_context(struct audit_buffer *ab)
+{
+	char *ctx = NULL;
+	unsigned len;
+	int error;
+	u32 sid;
+
+	security_current_getsecid_subj(&sid);
+	if (!sid)
+		return 0;
+
+	error = security_secid_to_secctx(sid, &ctx, &len);
+	if (error) {
+		if (error != -EINVAL)
+			goto error_path;
+		return 0;
+	}
+
+	audit_log_format(ab, " subj=%s", ctx);
+	security_release_secctx(ctx, len);
+	return 0;
+
+error_path:
+	audit_panic("error in audit_log_task_context");
+	return error;
+}
+EXPORT_SYMBOL(audit_log_task_context);
+
+void audit_log_d_path_exe(struct audit_buffer *ab,
+			  struct mm_struct *mm)
+{
+	struct file *exe_file;
+
+	if (!mm)
+		goto out_null;
+
+	exe_file = get_mm_exe_file(mm);
+	if (!exe_file)
+		goto out_null;
+
+	audit_log_d_path(ab, " exe=", &exe_file->f_path);
+	fput(exe_file);
+	return;
+out_null:
+	audit_log_format(ab, " exe=(null)");
+}
+
+struct tty_struct *audit_get_tty(void)
+{
+	struct tty_struct *tty = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&current->sighand->siglock, flags);
+	if (current->signal)
+		tty = tty_kref_get(current->signal->tty);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
+	return tty;
+}
+
+void audit_put_tty(struct tty_struct *tty)
+{
+	tty_kref_put(tty);
+}
+
+void audit_log_task_info(struct audit_buffer *ab)
+{
+	const struct cred *cred;
+	char comm[sizeof(current->comm)];
+	struct tty_struct *tty;
+
+	if (!ab)
+		return;
+
+	cred = current_cred();
+	tty = audit_get_tty();
+	audit_log_format(ab,
+			 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
+			 " euid=%u suid=%u fsuid=%u"
+			 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
+			 task_ppid_nr(current),
+			 task_tgid_nr(current),
+			 from_kuid(&init_user_ns, audit_get_loginuid(current)),
+			 from_kuid(&init_user_ns, cred->uid),
+			 from_kgid(&init_user_ns, cred->gid),
+			 from_kuid(&init_user_ns, cred->euid),
+			 from_kuid(&init_user_ns, cred->suid),
+			 from_kuid(&init_user_ns, cred->fsuid),
+			 from_kgid(&init_user_ns, cred->egid),
+			 from_kgid(&init_user_ns, cred->sgid),
+			 from_kgid(&init_user_ns, cred->fsgid),
+			 tty ? tty_name(tty) : "(none)",
+			 audit_get_sessionid(current));
+	audit_put_tty(tty);
+	audit_log_format(ab, " comm=");
+	audit_log_untrustedstring(ab, get_task_comm(comm, current));
+	audit_log_d_path_exe(ab, current->mm);
+	audit_log_task_context(ab);
+}
+EXPORT_SYMBOL(audit_log_task_info);
+
+/**
+ * audit_log_path_denied - report a path restriction denial
+ * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
+ * @operation: specific operation name
+ */
+void audit_log_path_denied(int type, const char *operation)
+{
+	struct audit_buffer *ab;
+
+	if (!audit_enabled || audit_dummy_context())
+		return;
+
+	/* Generate log with subject, operation, outcome. */
+	ab = audit_log_start(audit_context(), GFP_KERNEL, type);
+	if (!ab)
+		return;
+	audit_log_format(ab, "op=%s", operation);
+	audit_log_task_info(ab);
+	audit_log_format(ab, " res=0");
+	audit_log_end(ab);
+}
+
+/* global counter which is incremented every time something logs in */
+static atomic_t session_id = ATOMIC_INIT(0);
+
+static int audit_set_loginuid_perm(kuid_t loginuid)
+{
+	/* if we are unset, we don't need privs */
+	if (!audit_loginuid_set(current))
+		return 0;
+	/* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
+	if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
+		return -EPERM;
+	/* it is set, you need permission */
+	if (!capable(CAP_AUDIT_CONTROL))
+		return -EPERM;
+	/* reject if this is not an unset and we don't allow that */
+	if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
+				 && uid_valid(loginuid))
+		return -EPERM;
+	return 0;
+}
+
+static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
+				   unsigned int oldsessionid,
+				   unsigned int sessionid, int rc)
+{
+	struct audit_buffer *ab;
+	uid_t uid, oldloginuid, loginuid;
+	struct tty_struct *tty;
+
+	if (!audit_enabled)
+		return;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
+	if (!ab)
+		return;
+
+	uid = from_kuid(&init_user_ns, task_uid(current));
+	oldloginuid = from_kuid(&init_user_ns, koldloginuid);
+	loginuid = from_kuid(&init_user_ns, kloginuid);
+	tty = audit_get_tty();
+
+	audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
+	audit_log_task_context(ab);
+	audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
+			 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
+			 oldsessionid, sessionid, !rc);
+	audit_put_tty(tty);
+	audit_log_end(ab);
+}
+
+/**
+ * audit_set_loginuid - set current task's loginuid
+ * @loginuid: loginuid value
+ *
+ * Returns 0.
+ *
+ * Called (set) from fs/proc/base.c::proc_loginuid_write().
+ */
+int audit_set_loginuid(kuid_t loginuid)
+{
+	unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
+	kuid_t oldloginuid;
+	int rc;
+
+	oldloginuid = audit_get_loginuid(current);
+	oldsessionid = audit_get_sessionid(current);
+
+	rc = audit_set_loginuid_perm(loginuid);
+	if (rc)
+		goto out;
+
+	/* are we setting or clearing? */
+	if (uid_valid(loginuid)) {
+		sessionid = (unsigned int)atomic_inc_return(&session_id);
+		if (unlikely(sessionid == AUDIT_SID_UNSET))
+			sessionid = (unsigned int)atomic_inc_return(&session_id);
+	}
+
+	current->sessionid = sessionid;
+	current->loginuid = loginuid;
+out:
+	audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
+	return rc;
+}
+
+/**
+ * audit_signal_info - record signal info for shutting down audit subsystem
+ * @sig: signal value
+ * @t: task being signaled
+ *
+ * If the audit subsystem is being terminated, record the task (pid)
+ * and uid that is doing that.
+ */
+int audit_signal_info(int sig, struct task_struct *t)
+{
+	kuid_t uid = current_uid(), auid;
+
+	if (auditd_test_task(t) &&
+	    (sig == SIGTERM || sig == SIGHUP ||
+	     sig == SIGUSR1 || sig == SIGUSR2)) {
+		audit_sig_pid = task_tgid_nr(current);
+		auid = audit_get_loginuid(current);
+		if (uid_valid(auid))
+			audit_sig_uid = auid;
+		else
+			audit_sig_uid = uid;
+		security_current_getsecid_subj(&audit_sig_sid);
+	}
+
+	return audit_signal_info_syscall(t);
+}
+
+/**
+ * audit_log_end - end one audit record
+ * @ab: the audit_buffer
+ *
+ * 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 kthread 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)
+{
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+
+	if (!ab)
+		return;
+
+	if (audit_rate_check()) {
+		skb = ab->skb;
+		ab->skb = NULL;
+
+		/* 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;
+
+		/* queue the netlink packet and poke the kauditd thread */
+		skb_queue_tail(&audit_queue, skb);
+		wake_up_interruptible(&kauditd_wait);
+	} else
+		audit_log_lost("rate limit exceeded");
+
+	audit_buffer_free(ab);
+}
+
+/**
+ * audit_log - Log an audit record
+ * @ctx: audit context
+ * @gfp_mask: type of allocation
+ * @type: audit message type
+ * @fmt: format string to use
+ * @...: variable parameters matching the format string
+ *
+ * This is a convenience function that calls audit_log_start,
+ * audit_log_vformat, and audit_log_end.  It may be called
+ * in any context.
+ */
+void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
+	       const char *fmt, ...)
+{
+	struct audit_buffer *ab;
+	va_list args;
+
+	ab = audit_log_start(ctx, gfp_mask, type);
+	if (ab) {
+		va_start(args, fmt);
+		audit_log_vformat(ab, fmt, args);
+		va_end(args);
+		audit_log_end(ab);
+	}
+}
+
+EXPORT_SYMBOL(audit_log_start);
+EXPORT_SYMBOL(audit_log_end);
+EXPORT_SYMBOL(audit_log_format);
+EXPORT_SYMBOL(audit_log);