audit: listen in all network namespaces

Convert audit from only listening in init_net to use register_pernet_subsys()
to dynamically manage the netlink socket list.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

3 files changed, 61 insertions, 12 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index e88f599a2020..dd18747dde2b 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -63,6 +63,7 @@
 #include <linux/freezer.h>
 #include <linux/tty.h>
 #include <linux/pid_namespace.h>
+#include <net/netns/generic.h>
 
 #include "audit.h"
 
@@ -121,6 +122,7 @@ static atomic_t    audit_lost = ATOMIC_INIT(0);
 
 /* The netlink socket. */
 static struct sock *audit_sock;
+int audit_net_id;
 
 /* Hash for inode-based rules */
 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
@@ -176,6 +178,7 @@ struct audit_buffer {
 
 struct audit_reply {
         __u32 portid;
+        pid_t pid;
         struct sk_buff *skb;
 };
 
@@ -401,6 +404,7 @@ static void kauditd_send_skb(struct sk_buff *skb)
                 printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
                 audit_log_lost("auditd disappeared\n");
                 audit_pid = 0;
+                audit_sock = NULL;
                 /* we might get lucky and get this in the next auditd */
                 audit_hold_skb(skb);
         } else
@@ -482,15 +486,16 @@ static int kauditd_thread(void *dummy)
 int audit_send_list(void *_dest)
 {
         struct audit_netlink_list *dest = _dest;
-        __u32 portid = dest->portid;
         struct sk_buff *skb;
+        struct net *net = get_net_ns_by_pid(dest->pid);
+        struct audit_net *aunet = net_generic(net, audit_net_id);
 
         /* wait for parent to finish and send an ACK */
         mutex_lock(&audit_cmd_mutex);
         mutex_unlock(&audit_cmd_mutex);
 
         while ((skb = __skb_dequeue(&dest->q)) != NULL)
-                netlink_unicast(audit_sock, skb, portid, 0);
+                netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
 
         kfree(dest);
 
@@ -525,13 +530,15 @@ out_kfree_skb:
 static int audit_send_reply_thread(void *arg)
 {
         struct audit_reply *reply = (struct audit_reply *)arg;
+        struct net *net = get_net_ns_by_pid(reply->pid);
+        struct audit_net *aunet = net_generic(net, audit_net_id);
 
         mutex_lock(&audit_cmd_mutex);
         mutex_unlock(&audit_cmd_mutex);
 
         /* Ignore failure. It'll only happen if the sender goes away,
            because our timeout is set to infinite. */
-        netlink_unicast(audit_sock, reply->skb, reply->portid, 0);
+        netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
         kfree(reply);
         return 0;
 }
@@ -564,6 +571,7 @@ static void audit_send_reply(__u32 portid, int seq, int type, int done,
                 goto out;
 
         reply->portid = portid;
+        reply->pid = task_pid_vnr(current);
         reply->skb = skb;
 
         tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
@@ -791,6 +799,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                                 audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
                         audit_pid = new_pid;
                         audit_nlk_portid = NETLINK_CB(skb).portid;
+                        audit_sock = NETLINK_CB(skb).sk;
                 }
                 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) {
                         err = audit_set_rate_limit(status_get->rate_limit);
@@ -998,24 +1007,58 @@ static void audit_receive(struct sk_buff  *skb)
         mutex_unlock(&audit_cmd_mutex);
 }
 
-/* Initialize audit support at boot time. */
-static int __init audit_init(void)
+static int __net_init audit_net_init(struct net *net)
 {
-        int i;
         struct netlink_kernel_cfg cfg = {
                 .input  = audit_receive,
         };
 
+        struct audit_net *aunet = net_generic(net, audit_net_id);
+
+        pr_info("audit: initializing netlink socket in namespace\n");
+
+        aunet->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
+        if (aunet->nlsk == NULL)
+                return -ENOMEM;
+        if (!aunet->nlsk)
+                audit_panic("cannot initialize netlink socket in namespace");
+        else
+                aunet->nlsk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
+        return 0;
+}
+
+static void __net_exit audit_net_exit(struct net *net)
+{
+        struct audit_net *aunet = net_generic(net, audit_net_id);
+        struct sock *sock = aunet->nlsk;
+        if (sock == audit_sock) {
+                audit_pid = 0;
+                audit_sock = NULL;
+        }
+
+        rcu_assign_pointer(aunet->nlsk, NULL);
+        synchronize_net();
+        netlink_kernel_release(sock);
+}
+
+static struct pernet_operations __net_initdata audit_net_ops = {
+        .init = audit_net_init,
+        .exit = audit_net_exit,
+        .id = &audit_net_id,
+        .size = sizeof(struct audit_net),
+};
+
+/* Initialize audit support at boot time. */
+static int __init audit_init(void)
+{
+        int i;
+
         if (audit_initialized == AUDIT_DISABLED)
                 return 0;
 
-        printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
+        pr_info("audit: initializing netlink subsys (%s)\n",
                audit_default ? "enabled" : "disabled");
-        audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, &cfg);
-        if (!audit_sock)
-                audit_panic("cannot initialize netlink socket");
-        else
-                audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
+        register_pernet_subsys(&audit_net_ops);
 
         skb_queue_head_init(&audit_skb_queue);
         skb_queue_head_init(&audit_skb_hold_queue);
diff --git a/kernel/audit.h b/kernel/audit.h
index c7282444caea..0719b4547221 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -247,11 +247,16 @@ extern void		    audit_panic(const char *message);
 
 struct audit_netlink_list {
         __u32 portid;
+        pid_t pid;
         struct sk_buff_head q;
 };
 
 int audit_send_list(void *);
 
+struct audit_net {
+        struct sock *nlsk;
+};
+
 extern int selinux_audit_rule_update(void);
 
 extern struct mutex audit_filter_mutex;
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 08f7f7bef26c..d085cfbe416e 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1050,6 +1050,7 @@ int audit_receive_filter(int type, __u32 portid, int seq, void *data,
                 if (!dest)
                         return -ENOMEM;
                 dest->portid = portid;
+                dest->pid = task_pid_vnr(current);
                 skb_queue_head_init(&dest->q);
 
                 mutex_lock(&audit_filter_mutex);