From: Paul Moore <paul(a)paul-moore.com&gt; The retry queue is intended to provide a temporary buffer in the case of transient errors when communicating with auditd, it is not meant as a long life queue, that functionality is provided by the hold queue. This patch fixes a problem identified by Seth where the retry queue could grow uncontrollably if an auditd instance did not connect to the kernel to drain the queues. This commit fixes this by doing the following: * Make sure we always call auditd_reset() if we decide the connection with audit is really dead. There were some cases in kauditd_hold_skb() where we did not reset the connection, this patch relocates the reset calls to kauditd_thread() so all the error conditions are caught and the connection reset. As a side effect, this means we could move auditd_reset() and get rid of the forward definition at the top of kernel/audit.c. * We never checked the status of the auditd connection when processing the main audit queue which meant that the retry queue could grow unchecked. This patch adds a call to auditd_reset() after the main queue has been processed if auditd is not connected, the auditd_reset() call will make sure the retry and hold queues are correctly managed/flushed so that the retry queue remains reasonable. Reported-by: Seth Forshee <seth.forshee(a)canonical.com&gt; Signed-off-by: Paul Moore <paul(a)paul-moore.com&gt; --- kernel/audit.c | 67 +++++++++++++++++++++++++++----------------------------- 1 file changed, 32 insertions(+), 35 deletions(-) diff --git a/kernel/audit.c b/kernel/audit.c index 2f4964cfde0b..a871bf80fde1 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -160,7 +160,6 @@ static LIST_HEAD(audit_freelist); /* queue msgs to send via kauditd_task */ static struct sk_buff_head audit_queue; -static void kauditd_hold_skb(struct sk_buff *skb); /* queue msgs due to temporary unicast send problems */ static struct sk_buff_head audit_retry_queue; /* queue msgs waiting for new auditd connection */ @@ -454,30 +453,6 @@ static void auditd_set(int pid, u32 portid, struct net *net) } /** - * auditd_reset - Disconnect the auditd connection - * - * Description: - * Break the auditd/kauditd connection and move all the queued records into the - * hold queue in case auditd reconnects. - */ -static void auditd_reset(void) -{ - struct sk_buff *skb; - - /* if it isn't already broken, break the connection */ - rcu_read_lock(); - if (auditd_conn.pid) - auditd_set(0, 0, NULL); - rcu_read_unlock(); - - /* flush all of the main and retry queues to the hold queue */ - while ((skb = skb_dequeue(&audit_retry_queue))) - kauditd_hold_skb(skb); - while ((skb = skb_dequeue(&audit_queue))) - kauditd_hold_skb(skb); -} - -/** * kauditd_print_skb - Print the audit record to the ring buffer * @skb: audit record * @@ -505,9 +480,6 @@ static void kauditd_rehold_skb(struct sk_buff *skb) { /* put the record back in the queue at the same place */ skb_queue_head(&audit_hold_queue, skb); - - /* fail the auditd connection */ - auditd_reset(); } /** @@ -544,9 +516,6 @@ static void kauditd_hold_skb(struct sk_buff *skb) /* we have no other options - drop the message */ audit_log_lost("kauditd hold queue overflow"); kfree_skb(skb); - - /* fail the auditd connection */ - auditd_reset(); } /** @@ -567,6 +536,30 @@ static void kauditd_retry_skb(struct sk_buff *skb) } /** + * auditd_reset - Disconnect the auditd connection + * + * Description: + * Break the auditd/kauditd connection and move all the queued records into the + * hold queue in case auditd reconnects. + */ +static void auditd_reset(void) +{ + struct sk_buff *skb; + + /* if it isn't already broken, break the connection */ + rcu_read_lock(); + if (auditd_conn.pid) + auditd_set(0, 0, NULL); + rcu_read_unlock(); + + /* flush all of the main and retry queues to the hold queue */ + while ((skb = skb_dequeue(&audit_retry_queue))) + kauditd_hold_skb(skb); + while ((skb = skb_dequeue(&audit_queue))) + kauditd_hold_skb(skb); +} + +/** * auditd_send_unicast_skb - Send a record via unicast to auditd * @skb: audit record * @@ -758,6 +751,7 @@ static int kauditd_thread(void *dummy) NULL, kauditd_rehold_skb); if (rc < 0) { sk = NULL; + auditd_reset(); goto main_queue; } @@ -767,6 +761,7 @@ static int kauditd_thread(void *dummy) NULL, kauditd_hold_skb); if (rc < 0) { sk = NULL; + auditd_reset(); goto main_queue; } @@ -775,16 +770,18 @@ static int kauditd_thread(void *dummy) * 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 */ - kauditd_send_queue(sk, portid, &audit_queue, 1, - kauditd_send_multicast_skb, - kauditd_retry_skb); + rc = kauditd_send_queue(sk, portid, &audit_queue, 1, + kauditd_send_multicast_skb, + kauditd_retry_skb); + if (sk == NULL || rc < 0) + auditd_reset(); + sk = NULL; /* drop our netns reference, no auditd sends past this line */ if (net) { put_net(net); net = NULL; } - sk = NULL; /* we have processed all the queues so wake everyone */ wake_up(&audit_backlog_wait);