SELinux: Only store the network interface's ifindex

Instead of storing the packet's network interface name store the ifindex.  This
allows us to defer the need to lookup the net_device structure until the audit
record is generated meaning that in the majority of cases we never need to
bother with this at all.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>

3 files changed, 15 insertions, 6 deletions

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 81b3dff3cbf0..e8529e2f51e5 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -661,9 +661,18 @@ void avc_audit(u32 ssid, u32 tsid,
                                                     "daddr", "dest");
                                 break;
                         }
-                        if (a->u.net.netif)
-                                audit_log_format(ab, " netif=%s",
-                                        a->u.net.netif);
+                        if (a->u.net.netif > 0) {
+                                struct net_device *dev;
+
+                                /* NOTE: we always use init's namespace */
+                                dev = dev_get_by_index(&init_net,
+                                                       a->u.net.netif);
+                                if (dev) {
+                                        audit_log_format(ab, " netif=%s",
+                                                         dev->name);
+                                        dev_put(dev);
+                                }
+                        }
                         break;
                 }
         }
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index be544332214c..1a1fa3f20ef0 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3928,7 +3928,7 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
                 family = PF_INET;
 
         AVC_AUDIT_DATA_INIT(&ad, NET);
-        ad.u.net.netif = skb->dev ? skb->dev->name : "[unknown]";
+        ad.u.net.netif = skb->iif;
         ad.u.net.family = family;
 
         err = selinux_parse_skb(skb, &ad, &addrp, &len, 1, NULL);
@@ -4259,7 +4259,7 @@ static unsigned int selinux_ip_postroute_last(unsigned int hooknum,
         sksec = sk->sk_security;
 
         AVC_AUDIT_DATA_INIT(&ad, NET);
-        ad.u.net.netif = dev->name;
+        ad.u.net.netif = dev->ifindex;
         ad.u.net.family = family;
 
         err = selinux_parse_skb(skb, &ad, &addrp, &len, 0, &proto);
diff --git a/security/selinux/include/avc.h b/security/selinux/include/avc.h
index 553607a19e92..80c28fa6621c 100644
--- a/security/selinux/include/avc.h
+++ b/security/selinux/include/avc.h
@@ -51,7 +51,7 @@ struct avc_audit_data {
                         struct inode *inode;
                 } fs;
                 struct {
-                        char *netif;
+                        int netif;
                         struct sock *sk;
                         u16 family;
                         __be16 dport;