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Diffstat (limited to '')
| -rw-r--r-- | kernel/audit.c | 2463 |
1 files changed, 2463 insertions, 0 deletions
diff --git a/kernel/audit.c b/kernel/audit.c new file mode 100644 index 0000000000..16205dd298 --- /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(¤t->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(¤t->sighand->siglock, flags); + if (current->signal) + tty = tty_kref_get(current->signal->tty); + spin_unlock_irqrestore(¤t->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); |