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Commit b6c7c115 authored by Paul Moore's avatar Paul Moore
Browse files

audit: store the auditd PID as a pid struct instead of pid_t 



This is arguably the right thing to do, and will make it easier when
we start supporting multiple audit daemons in different namespaces.

Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 45a0642b

kernel/audit.c

+57 −27
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ 
#include <linux/rcupdate.h>

#include <linux/mutex.h>

#include <linux/gfp.h>

#include <linux/pid.h>



#include <linux/audit.h>
@@ -117,7 +118,7 @@ struct audit_net { 
 * or the included spinlock for writing.

 */

static struct auditd_connection {

	int pid;

	struct pid *pid;

	u32 portid;

	struct net *net;

	spinlock_t lock;
@@ -220,17 +221,40 @@ struct audit_reply { 
 * Description:

 * Return 1 if the task is a registered audit daemon, 0 otherwise.

 */

int auditd_test_task(const struct task_struct *task)

int auditd_test_task(struct task_struct *task)

{

	int rc;



	rcu_read_lock();

	rc = (auditd_conn.pid && task->tgid == auditd_conn.pid ? 1 : 0);

	rc = (auditd_conn.pid && auditd_conn.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.

 */

static pid_t auditd_pid_vnr(const struct auditd_connection *auditd)

{

	pid_t pid;



	rcu_read_lock();

	if (!auditd || !auditd->pid)

		pid = 0;

	else

		pid = pid_vnr(auditd->pid);

	rcu_read_unlock();



	return pid;

}



/**

 * audit_get_sk - Return the audit socket for the given network namespace

 * @net: the destination network namespace
@@ -428,12 +452,17 @@ static int audit_set_failure(u32 state) 
 * This function will obtain and drop network namespace references as

 * necessary.

 */

static void auditd_set(int pid, u32 portid, struct net *net)

static void auditd_set(struct pid *pid, u32 portid, struct net *net)

{

	unsigned long flags;



	spin_lock_irqsave(&auditd_conn.lock, flags);

	auditd_conn.pid = pid;

	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);
@@ -1059,11 +1088,13 @@ static int audit_set_feature(struct sk_buff *skb) 
	return 0;

}



static int audit_replace(pid_t pid)

static int audit_replace(struct pid *pid)

{

	pid_t pvnr;

	struct sk_buff *skb;



	skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pid, sizeof(pid));

	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);
@@ -1093,9 +1124,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 
		memset(&s, 0, sizeof(s));

		s.enabled		= audit_enabled;

		s.failure		= audit_failure;

		rcu_read_lock();

		s.pid			= auditd_conn.pid;

		rcu_read_unlock();

		/* NOTE: use pid_vnr() so the PID is relative to the current

		 *       namespace */

		s.pid			= auditd_pid_vnr(&auditd_conn);

		s.rate_limit		= audit_rate_limit;

		s.backlog_limit		= audit_backlog_limit;

		s.lost			= atomic_read(&audit_lost);
@@ -1121,36 +1152,36 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 
				return err;

		}

		if (s.mask & AUDIT_STATUS_PID) {

			/* NOTE: we are using task_tgid_vnr() 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 */

			int new_pid = s.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;

			pid_t requesting_pid = task_tgid_vnr(current);

			struct pid *req_pid = task_tgid(current);



			/* sanity check - PID values must match */

			if (new_pid != pid_vnr(req_pid))

				return -EINVAL;



			/* test the auditd connection */

			audit_replace(requesting_pid);

			audit_replace(req_pid);



			rcu_read_lock();

			auditd_pid = auditd_conn.pid;

			auditd_pid = auditd_pid_vnr(&auditd_conn);

			/* only the current auditd can unregister itself */

			if ((!new_pid) && (requesting_pid != auditd_pid)) {

				rcu_read_unlock();

			if ((!new_pid) && (new_pid != auditd_pid)) {

				audit_log_config_change("audit_pid", new_pid,

							auditd_pid, 0);

				return -EACCES;

			}

			/* replacing a healthy auditd is not allowed */

			if (auditd_pid && new_pid) {

				rcu_read_unlock();

				audit_log_config_change("audit_pid", new_pid,

							auditd_pid, 0);

				return -EEXIST;

			}

			rcu_read_unlock();



			if (audit_enabled != AUDIT_OFF)

				audit_log_config_change("audit_pid", new_pid,
@@ -1158,8 +1189,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 


			if (new_pid) {

				/* register a new auditd connection */

				auditd_set(new_pid,

					   NETLINK_CB(skb).portid,

				auditd_set(req_pid, NETLINK_CB(skb).portid,

					   sock_net(NETLINK_CB(skb).sk));

				/* try to process any backlog */

				wake_up_interruptible(&kauditd_wait);

kernel/audit.h

+1 −1
Original line number Diff line number Diff line
@@ -218,7 +218,7 @@ extern void audit_log_name(struct audit_context *context, 
			   struct audit_names *n, const struct path *path,

			   int record_num, int *call_panic);



extern int auditd_test_task(const struct task_struct *task);

extern int auditd_test_task(struct task_struct *task);



#define AUDIT_INODE_BUCKETS	32

extern struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];