#include <linux/mutex.h>
#include <linux/gfp.h>
#include <linux/pid.h>
+#include <linux/slab.h>
#include <linux/audit.h>
* @pid: auditd PID
* @portid: netlink portid
* @net: the associated network namespace
- * @lock: spinlock to protect write access
+ * @rcu: RCU head
*
* Description:
* This struct is RCU protected; you must either hold the RCU lock for reading
- * or the included spinlock for writing.
+ * or the associated spinlock for writing.
*/
static struct auditd_connection {
struct pid *pid;
u32 portid;
struct net *net;
- spinlock_t lock;
-} auditd_conn;
+ struct rcu_head rcu;
+} *auditd_conn = NULL;
+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
/* Hash for inode-based rules */
struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
-/* The audit_freelist is a list of pre-allocated audit buffers (if more
- * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
- * being placed on the freelist). */
-static DEFINE_SPINLOCK(audit_freelist_lock);
-static int audit_freelist_count;
-static LIST_HEAD(audit_freelist);
+static struct kmem_cache *audit_buffer_cache;
/* queue msgs to send via kauditd_task */
static struct sk_buff_head audit_queue;
* should be at least that large. */
#define AUDIT_BUFSIZ 1024
-/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
- * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
-#define AUDIT_MAXFREE (2*NR_CPUS)
-
/* 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 list_head list;
struct sk_buff *skb; /* formatted skb ready to send */
struct audit_context *ctx; /* NULL or associated context */
gfp_t gfp_mask;
int auditd_test_task(struct task_struct *task)
{
int rc;
+ struct auditd_connection *ac;
rcu_read_lock();
- rc = (auditd_conn.pid && auditd_conn.pid == task_tgid(task) ? 1 : 0);
+ ac = rcu_dereference(auditd_conn);
+ rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
rcu_read_unlock();
return rc;
/**
* auditd_pid_vnr - Return the auditd PID relative to the namespace
- * @auditd: the auditd connection
*
* Description:
- * Returns the PID in relation to the namespace, 0 on failure. This function
- * takes the RCU read lock internally, but if the caller needs to protect the
- * auditd_connection pointer it should take the RCU read lock as well.
+ * Returns the PID in relation to the namespace, 0 on failure.
*/
-static pid_t auditd_pid_vnr(const struct auditd_connection *auditd)
+static pid_t auditd_pid_vnr(void)
{
pid_t pid;
+ const struct auditd_connection *ac;
rcu_read_lock();
- if (!auditd || !auditd->pid)
+ ac = rcu_dereference(auditd_conn);
+ if (!ac || !ac->pid)
pid = 0;
else
- pid = pid_vnr(auditd->pid);
+ pid = pid_vnr(ac->pid);
rcu_read_unlock();
return pid;
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
*
* Description:
* This function will obtain and drop network namespace references as
- * necessary.
+ * necessary. Returns zero on success, negative values on failure.
*/
-static void auditd_set(struct pid *pid, u32 portid, struct net *net)
+static int auditd_set(struct pid *pid, u32 portid, struct net *net)
{
unsigned long flags;
+ struct auditd_connection *ac_old, *ac_new;
- spin_lock_irqsave(&auditd_conn.lock, flags);
- if (auditd_conn.pid)
- put_pid(auditd_conn.pid);
- if (pid)
- auditd_conn.pid = get_pid(pid);
- else
- auditd_conn.pid = NULL;
- auditd_conn.portid = portid;
- if (auditd_conn.net)
- put_net(auditd_conn.net);
- if (net)
- auditd_conn.net = get_net(net);
- else
- auditd_conn.net = NULL;
- spin_unlock_irqrestore(&auditd_conn.lock, flags);
+ 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;
}
/**
/**
* 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.
+ * 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(void)
+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 */
- rcu_read_lock();
- if (auditd_conn.pid)
- auditd_set(0, 0, NULL);
- rcu_read_unlock();
+ 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);
- /* flush all of the main and retry queues to the hold queue */
+ 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);
- while ((skb = skb_dequeue(&audit_queue)))
- kauditd_hold_skb(skb);
}
/**
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
* section netlink_unicast() should safely return an error */
rcu_read_lock();
- if (!auditd_conn.pid) {
+ ac = rcu_dereference(auditd_conn);
+ if (!ac) {
rcu_read_unlock();
+ kfree_skb(skb);
rc = -ECONNREFUSED;
goto err;
}
- net = auditd_conn.net;
- get_net(net);
+ net = get_net(ac->net);
sk = audit_get_sk(net);
- portid = auditd_conn.portid;
+ portid = ac->portid;
rcu_read_unlock();
rc = netlink_unicast(sk, skb, portid, 0);
return rc;
err:
- if (rc == -ECONNREFUSED)
- auditd_reset();
+ if (ac && rc == -ECONNREFUSED)
+ auditd_reset(ac);
return rc;
}
u32 portid = 0;
struct net *net = NULL;
struct sock *sk = NULL;
+ struct auditd_connection *ac;
#define UNICAST_RETRIES 5
while (!kthread_should_stop()) {
/* NOTE: see the lock comments in auditd_send_unicast_skb() */
rcu_read_lock();
- if (!auditd_conn.pid) {
+ ac = rcu_dereference(auditd_conn);
+ if (!ac) {
rcu_read_unlock();
goto main_queue;
}
- net = auditd_conn.net;
- get_net(net);
+ net = get_net(ac->net);
sk = audit_get_sk(net);
- portid = auditd_conn.portid;
+ 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) {
+ if (ac && rc < 0) {
sk = NULL;
- auditd_reset();
+ auditd_reset(ac);
goto main_queue;
}
rc = kauditd_send_queue(sk, portid,
&audit_retry_queue, UNICAST_RETRIES,
NULL, kauditd_hold_skb);
- if (rc < 0) {
+ if (ac && rc < 0) {
sk = NULL;
- auditd_reset();
+ auditd_reset(ac);
goto 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 retry queue */
+ * multicast send and move the record to the hold queue */
rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
kauditd_send_multicast_skb,
- kauditd_retry_skb);
- if (sk == NULL || rc < 0)
- auditd_reset();
+ (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 */
s.failure = audit_failure;
/* NOTE: use pid_vnr() so the PID is relative to the current
* namespace */
- s.pid = auditd_pid_vnr(&auditd_conn);
+ s.pid = auditd_pid_vnr();
s.rate_limit = audit_rate_limit;
s.backlog_limit = audit_backlog_limit;
s.lost = atomic_read(&audit_lost);
/* test the auditd connection */
audit_replace(req_pid);
- auditd_pid = auditd_pid_vnr(&auditd_conn);
+ auditd_pid = auditd_pid_vnr();
/* only the current auditd can unregister itself */
if ((!new_pid) && (new_pid != auditd_pid)) {
audit_log_config_change("audit_pid", new_pid,
return -EEXIST;
}
- if (audit_enabled != AUDIT_OFF)
- audit_log_config_change("audit_pid", new_pid,
- auditd_pid, 1);
-
if (new_pid) {
/* register a new auditd connection */
- auditd_set(req_pid, NETLINK_CB(skb).portid,
- sock_net(NETLINK_CB(skb).sk));
+ 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
+ } else {
+ if (audit_enabled != AUDIT_OFF)
+ audit_log_config_change("audit_pid",
+ new_pid,
+ auditd_pid, 1);
+
/* unregister the auditd connection */
- auditd_reset();
+ auditd_reset(NULL);
+ }
}
if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
err = audit_set_rate_limit(s.rate_limit);
{
struct audit_net *aunet = net_generic(net, audit_net_id);
- rcu_read_lock();
- if (net == auditd_conn.net)
- auditd_reset();
- rcu_read_unlock();
+ /* 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);
}
if (audit_initialized == AUDIT_DISABLED)
return 0;
- memset(&auditd_conn, 0, sizeof(auditd_conn));
- spin_lock_init(&auditd_conn.lock);
+ 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);
static void audit_buffer_free(struct audit_buffer *ab)
{
- unsigned long flags;
-
if (!ab)
return;
kfree_skb(ab->skb);
- spin_lock_irqsave(&audit_freelist_lock, flags);
- if (audit_freelist_count > AUDIT_MAXFREE)
- kfree(ab);
- else {
- audit_freelist_count++;
- list_add(&ab->list, &audit_freelist);
- }
- spin_unlock_irqrestore(&audit_freelist_lock, flags);
+ kmem_cache_free(audit_buffer_cache, ab);
}
-static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
- gfp_t gfp_mask, int type)
+static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
+ gfp_t gfp_mask, int type)
{
- unsigned long flags;
- struct audit_buffer *ab = NULL;
- struct nlmsghdr *nlh;
-
- spin_lock_irqsave(&audit_freelist_lock, flags);
- if (!list_empty(&audit_freelist)) {
- ab = list_entry(audit_freelist.next,
- struct audit_buffer, list);
- list_del(&ab->list);
- --audit_freelist_count;
- }
- spin_unlock_irqrestore(&audit_freelist_lock, flags);
-
- if (!ab) {
- ab = kmalloc(sizeof(*ab), gfp_mask);
- if (!ab)
- goto err;
- }
+ struct audit_buffer *ab;
- ab->ctx = ctx;
- ab->gfp_mask = gfp_mask;
+ 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;
- nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
- if (!nlh)
- goto out_kfree_skb;
+ ab->ctx = ctx;
+ ab->gfp_mask = gfp_mask;
return ab;
-out_kfree_skb:
- kfree_skb(ab->skb);
- ab->skb = NULL;
err:
audit_buffer_free(ab);
return NULL;
}
static inline void audit_get_stamp(struct audit_context *ctx,
- struct timespec *t, unsigned int *serial)
+ struct timespec64 *t, unsigned int *serial)
{
if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
- *t = CURRENT_TIME;
+ ktime_get_real_ts64(t);
*serial = audit_serial();
}
}
int type)
{
struct audit_buffer *ab;
- struct timespec t;
+ struct timespec64 t;
unsigned int uninitialized_var(serial);
if (audit_initialized != AUDIT_INITIALIZED)
}
audit_get_stamp(ab->ctx, &t, &serial);
- audit_log_format(ab, "audit(%lu.%03lu:%u): ",
- t.tv_sec, t.tv_nsec/1000000, serial);
+ audit_log_format(ab, "audit(%llu.%03lu:%u): ",
+ (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
return ab;
}
static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
{
- kernel_cap_t *perm = &name->fcap.permitted;
- kernel_cap_t *inh = &name->fcap.inheritable;
- int log = 0;
-
- if (!cap_isclear(*perm)) {
- audit_log_cap(ab, "cap_fp", perm);
- log = 1;
- }
- if (!cap_isclear(*inh)) {
- audit_log_cap(ab, "cap_fi", inh);
- log = 1;
- }
-
- if (log)
- audit_log_format(ab, " cap_fe=%d cap_fver=%x",
- name->fcap.fE, name->fcap_ver);
+ audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
+ audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
+ audit_log_format(ab, " cap_fe=%d cap_fver=%x",
+ name->fcap.fE, name->fcap_ver);
}
static inline int audit_copy_fcaps(struct audit_names *name,
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