diff options
| author | David Woodhouse <dwmw2@shinybook.infradead.org> | 2005-07-02 14:08:48 +0100 |
|---|---|---|
| committer | David Woodhouse <dwmw2@shinybook.infradead.org> | 2005-07-02 14:08:48 +0100 |
| commit | ac4cec443a80bfde829516e7a7db10f7325aa528 (patch) | |
| tree | 599801be12aa415d1c734cde37b1c2378fc6fe98 /kernel/audit.c | |
| parent | 7b430437c0de81681ecfa8efa8f55823df733529 (diff) | |
| download | lwn-ac4cec443a80bfde829516e7a7db10f7325aa528.tar.gz lwn-ac4cec443a80bfde829516e7a7db10f7325aa528.zip | |
AUDIT: Stop waiting for backlog after audit_panic() happens
We force a rate-limit on auditable events by making them wait for space
on the backlog queue. However, if auditd really is AWOL then this could
potentially bring the entire system to a halt, depending on the audit
rules in effect.
Firstly, make sure the wait time is honoured correctly -- it's the
maximum time the process should wait, rather than the time to wait
_each_ time round the loop. We were getting re-woken _each_ time a
packet was dequeued, and the timeout was being restarted each time.
Secondly, reset the wait time after audit_panic() is called. In general
this will be reset to zero, to allow progress to be made. If the system
is configured to _actually_ panic on audit_panic() then that will
already have happened; otherwise we know that audit records are being
lost anyway.
These two tunables can't be exposed via AUDIT_GET and AUDIT_SET because
those aren't particularly well-designed. It probably should have been
done by sysctls or sysfs anyway -- one for a later patch.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Diffstat (limited to 'kernel/audit.c')
| -rw-r--r-- | kernel/audit.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/kernel/audit.c b/kernel/audit.c index 2617d0552400..b683f2b5e866 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -79,6 +79,8 @@ static int audit_rate_limit; /* Number of outstanding audit_buffers allowed. */ static int audit_backlog_limit = 64; +static int audit_backlog_wait_time = 60 * HZ; +static int audit_backlog_wait_overflow = 0; /* The identity of the user shutting down the audit system. */ uid_t audit_sig_uid = -1; @@ -655,6 +657,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, int gfp_mask, struct timespec t; unsigned int serial; int reserve; + unsigned long timeout_start = jiffies; if (!audit_initialized) return NULL; @@ -667,8 +670,9 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, int gfp_mask, while (audit_backlog_limit && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) { - if (gfp_mask & __GFP_WAIT) { - int ret = 1; + if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time + && time_before(jiffies, timeout_start + audit_backlog_wait_time)) { + /* Wait for auditd to drain the queue a little */ DECLARE_WAITQUEUE(wait, current); set_current_state(TASK_INTERRUPTIBLE); @@ -676,12 +680,11 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, int gfp_mask, if (audit_backlog_limit && skb_queue_len(&audit_skb_queue) > audit_backlog_limit) - ret = schedule_timeout(HZ * 60); + schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies); __set_current_state(TASK_RUNNING); remove_wait_queue(&audit_backlog_wait, &wait); - if (ret) - continue; + continue; } if (audit_rate_check()) printk(KERN_WARNING @@ -690,6 +693,8 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, int gfp_mask, skb_queue_len(&audit_skb_queue), audit_backlog_limit); audit_log_lost("backlog limit exceeded"); + audit_backlog_wait_time = audit_backlog_wait_overflow; + wake_up(&audit_backlog_wait); return NULL; } |