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Commit 320f1b1e authored by Eric Paris's avatar Eric Paris Committed by Al Viro
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[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: default avatarEric Paris <eparis@redhat.com>
parent 148b38dc

kernel/audit.c

+18 −9
Original line number Diff line number Diff line
@@ -166,6 +166,7 @@ void audit_panic(const char *message) 
	case AUDIT_FAIL_SILENT:

		break;

	case AUDIT_FAIL_PRINTK:

		if (printk_ratelimit())

			printk(KERN_ERR "audit: %s\n", message);

		break;

	case AUDIT_FAIL_PANIC:
@@ -234,8 +235,10 @@ void audit_log_lost(const char *message) 
	}



	if (print) {

		if (printk_ratelimit())

			printk(KERN_WARNING

		       "audit: audit_lost=%d audit_rate_limit=%d audit_backlog_limit=%d\n",

				"audit: audit_lost=%d audit_rate_limit=%d "

				"audit_backlog_limit=%d\n",

				atomic_read(&audit_lost),

				audit_rate_limit,

				audit_backlog_limit);
@@ -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);