From 320f1b1ed28c601cc152053a2f428a126cb608bc Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Wed, 23 Jan 2008 22:55:05 -0500 Subject: [PATCH] [AUDIT] ratelimit printk messages audit some printk messages from the audit system can become excessive. This patch ratelimits those messages. It was found that messages, such as the audit backlog lost printk message could flood the logs to the point that a machine could take an nmi watchdog hit or otherwise become unresponsive. Signed-off-by: Eric Paris --- kernel/audit.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/kernel/audit.c b/kernel/audit.c index 9e3e457ddfb..c8555b18021 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -166,7 +166,8 @@ void audit_panic(const char *message) case AUDIT_FAIL_SILENT: break; case AUDIT_FAIL_PRINTK: - printk(KERN_ERR "audit: %s\n", message); + if (printk_ratelimit()) + printk(KERN_ERR "audit: %s\n", message); break; case AUDIT_FAIL_PANIC: panic("audit: %s\n", message); @@ -234,11 +235,13 @@ void audit_log_lost(const char *message) } if (print) { - printk(KERN_WARNING - "audit: audit_lost=%d audit_rate_limit=%d audit_backlog_limit=%d\n", - atomic_read(&audit_lost), - audit_rate_limit, - audit_backlog_limit); + if (printk_ratelimit()) + printk(KERN_WARNING + "audit: audit_lost=%d audit_rate_limit=%d " + "audit_backlog_limit=%d\n", + atomic_read(&audit_lost), + audit_rate_limit, + audit_backlog_limit); audit_panic(message); } } @@ -352,7 +355,11 @@ static int kauditd_thread(void *dummy) audit_pid = 0; } } else { - printk(KERN_NOTICE "%s\n", skb->data + NLMSG_SPACE(0)); + if (printk_ratelimit()) + printk(KERN_NOTICE "%s\n", skb->data + + NLMSG_SPACE(0)); + else + audit_log_lost("printk limit exceeded\n"); kfree_skb(skb); } } else { @@ -1066,7 +1073,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, remove_wait_queue(&audit_backlog_wait, &wait); continue; } - if (audit_rate_check()) + if (audit_rate_check() && printk_ratelimit()) printk(KERN_WARNING "audit: audit_backlog=%d > " "audit_backlog_limit=%d\n", @@ -1349,9 +1356,11 @@ void audit_log_end(struct audit_buffer *ab) skb_queue_tail(&audit_skb_queue, ab->skb); ab->skb = NULL; wake_up_interruptible(&kauditd_wait); - } else { + } else if (printk_ratelimit()) { struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, ab->skb->data + NLMSG_SPACE(0)); + } else { + audit_log_lost("printk limit exceeded\n"); } } audit_buffer_free(ab); -- 2.41.0