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Diffstat (limited to 'kernel/audit.c')
-rw-r--r--kernel/audit.c102
1 files changed, 81 insertions, 21 deletions
diff --git a/kernel/audit.c b/kernel/audit.c
index ad6d1abfa1d..fee9052eb5c 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -126,6 +126,8 @@ static int audit_freelist_count;
static LIST_HEAD(audit_freelist);
static struct sk_buff_head audit_skb_queue;
+/* queue of skbs to send to auditd when/if it comes back */
+static struct sk_buff_head audit_skb_hold_queue;
static struct task_struct *kauditd_task;
static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
@@ -347,30 +349,83 @@ static int audit_set_failure(int state, uid_t loginuid, u32 sessionid, u32 sid)
loginuid, sessionid, sid);
}
+/*
+ * Queue skbs to be sent to auditd when/if it comes back. These skbs should
+ * already have been sent via prink/syslog and so if these messages are dropped
+ * it is not a huge concern since we already passed the audit_log_lost()
+ * notification and stuff. This is just nice to get audit messages during
+ * boot before auditd is running or messages generated while auditd is stopped.
+ * This only holds messages is audit_default is set, aka booting with audit=1
+ * or building your kernel that way.
+ */
+static void audit_hold_skb(struct sk_buff *skb)
+{
+ if (audit_default &&
+ skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit)
+ skb_queue_tail(&audit_skb_hold_queue, skb);
+ else
+ kfree_skb(skb);
+}
+
+static void kauditd_send_skb(struct sk_buff *skb)
+{
+ int err;
+ /* take a reference in case we can't send it and we want to hold it */
+ skb_get(skb);
+ err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0);
+ if (err < 0) {
+ BUG_ON(err != -ECONNREFUSED); /* Shoudn't happen */
+ printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
+ audit_log_lost("auditd dissapeared\n");
+ audit_pid = 0;
+ /* we might get lucky and get this in the next auditd */
+ audit_hold_skb(skb);
+ } else
+ /* drop the extra reference if sent ok */
+ kfree_skb(skb);
+}
+
static int kauditd_thread(void *dummy)
{
struct sk_buff *skb;
set_freezable();
while (!kthread_should_stop()) {
+ /*
+ * if auditd just started drain the queue of messages already
+ * sent to syslog/printk. remember loss here is ok. we already
+ * called audit_log_lost() if it didn't go out normally. so the
+ * race between the skb_dequeue and the next check for audit_pid
+ * doesn't matter.
+ *
+ * if you ever find kauditd to be too slow we can get a perf win
+ * by doing our own locking and keeping better track if there
+ * are messages in this queue. I don't see the need now, but
+ * in 5 years when I want to play with this again I'll see this
+ * note and still have no friggin idea what i'm thinking today.
+ */
+ if (audit_default && audit_pid) {
+ skb = skb_dequeue(&audit_skb_hold_queue);
+ if (unlikely(skb)) {
+ while (skb && audit_pid) {
+ kauditd_send_skb(skb);
+ skb = skb_dequeue(&audit_skb_hold_queue);
+ }
+ }
+ }
+
skb = skb_dequeue(&audit_skb_queue);
wake_up(&audit_backlog_wait);
if (skb) {
- if (audit_pid) {
- int err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0);
- if (err < 0) {
- BUG_ON(err != -ECONNREFUSED); /* Shoudn't happen */
- printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
- audit_log_lost("auditd dissapeared\n");
- audit_pid = 0;
- }
- } else {
+ if (audit_pid)
+ kauditd_send_skb(skb);
+ else {
if (printk_ratelimit())
- printk(KERN_NOTICE "%s\n", skb->data +
- NLMSG_SPACE(0));
+ printk(KERN_NOTICE "%s\n", skb->data + NLMSG_SPACE(0));
else
audit_log_lost("printk limit exceeded\n");
- kfree_skb(skb);
+
+ audit_hold_skb(skb);
}
} else {
DECLARE_WAITQUEUE(wait, current);
@@ -885,6 +940,7 @@ static int __init audit_init(void)
audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
skb_queue_head_init(&audit_skb_queue);
+ skb_queue_head_init(&audit_skb_hold_queue);
audit_initialized = 1;
audit_enabled = audit_default;
audit_ever_enabled |= !!audit_default;
@@ -1363,19 +1419,23 @@ void audit_log_end(struct audit_buffer *ab)
audit_log_lost("rate limit exceeded");
} else {
struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
+ nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
+
if (audit_pid) {
- nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
skb_queue_tail(&audit_skb_queue, ab->skb);
- ab->skb = NULL;
wake_up_interruptible(&kauditd_wait);
- } else if (nlh->nlmsg_type != AUDIT_EOE) {
- if (printk_ratelimit()) {
- printk(KERN_NOTICE "type=%d %s\n",
- nlh->nlmsg_type,
- ab->skb->data + NLMSG_SPACE(0));
- } else
- audit_log_lost("printk limit exceeded\n");
+ } else {
+ if (nlh->nlmsg_type != AUDIT_EOE) {
+ if (printk_ratelimit()) {
+ 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_hold_skb(ab->skb);
}
+ ab->skb = NULL;
}
audit_buffer_free(ab);
}