SELinux: Add warning messages on network denial due to error

Currently network traffic can be sliently dropped due to non-avc errors which
can lead to much confusion when trying to debug the problem.  This patch adds
warning messages so that when these events occur there is a user visible
notification.

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

3 files changed, 40 insertions, 8 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b3c064744d32..81bfcf114484 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3443,6 +3443,11 @@ static int selinux_parse_skb(struct sk_buff *skb, struct avc_audit_data *ad,
                 break;
         }
 
+        if (unlikely(ret))
+                printk(KERN_WARNING
+                       "SELinux: failure in selinux_parse_skb(),"
+                       " unable to parse packet\n");
+
         return ret;
 }
 
@@ -3463,6 +3468,7 @@ static int selinux_parse_skb(struct sk_buff *skb, struct avc_audit_data *ad,
  */
 static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
 {
+        int err;
         u32 xfrm_sid;
         u32 nlbl_sid;
         u32 nlbl_type;
@@ -3470,10 +3476,13 @@ static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
         selinux_skb_xfrm_sid(skb, &xfrm_sid);
         selinux_netlbl_skbuff_getsid(skb, family, &nlbl_type, &nlbl_sid);
 
-        if (security_net_peersid_resolve(nlbl_sid, nlbl_type,
-                                         xfrm_sid,
-                                         sid) != 0)
+        err = security_net_peersid_resolve(nlbl_sid, nlbl_type, xfrm_sid, sid);
+        if (unlikely(err)) {
+                printk(KERN_WARNING
+                       "SELinux: failure in selinux_skb_peerlbl_sid(),"
+                       " unable to determine packet's peer label\n");
                 return -EACCES;
+        }
 
         return 0;
 }
@@ -3925,8 +3934,13 @@ static int selinux_sock_rcv_skb_iptables_compat(struct sock *sk,
         err = security_port_sid(sk->sk_family, sk->sk_type,
                                 sk->sk_protocol, ntohs(ad->u.net.sport),
                                 &port_sid);
-        if (err)
+        if (unlikely(err)) {
+                printk(KERN_WARNING
+                       "SELinux: failure in"
+                       " selinux_sock_rcv_skb_iptables_compat(),"
+                       " network port label not found\n");
                 return err;
+        }
         return avc_has_perm(sk_sid, port_sid, sk_class, recv_perm, ad);
 }
 
@@ -4343,8 +4357,13 @@ static int selinux_ip_postroute_iptables_compat(struct sock *sk,
         err = security_port_sid(sk->sk_family, sk->sk_type,
                                 sk->sk_protocol, ntohs(ad->u.net.dport),
                                 &port_sid);
-        if (err)
+        if (unlikely(err)) {
+                printk(KERN_WARNING
+                       "SELinux: failure in"
+                       " selinux_ip_postroute_iptables_compat(),"
+                       " network port label not found\n");
                 return err;
+        }
         return avc_has_perm(sk_sid, port_sid, sk_class, send_perm, ad);
 }
 
diff --git a/security/selinux/netif.c b/security/selinux/netif.c
index ee49a7382875..013d3117a86b 100644
--- a/security/selinux/netif.c
+++ b/security/selinux/netif.c
@@ -157,8 +157,12 @@ static int sel_netif_sid_slow(int ifindex, u32 *sid)
          * currently support containers */
 
         dev = dev_get_by_index(&init_net, ifindex);
-        if (dev == NULL)
+        if (unlikely(dev == NULL)) {
+                printk(KERN_WARNING
+                       "SELinux: failure in sel_netif_sid_slow(),"
+                       " invalid network interface (%d)\n", ifindex);
                 return -ENOENT;
+        }
 
         spin_lock_bh(&sel_netif_lock);
         netif = sel_netif_find(ifindex);
@@ -184,8 +188,13 @@ static int sel_netif_sid_slow(int ifindex, u32 *sid)
 out:
         spin_unlock_bh(&sel_netif_lock);
         dev_put(dev);
-        if (ret != 0)
+        if (unlikely(ret)) {
+                printk(KERN_WARNING
+                       "SELinux: failure in sel_netif_sid_slow(),"
+                       " unable to determine network interface label (%d)\n",
+                       ifindex);
                 kfree(new);
+        }
         return ret;
 }
 
diff --git a/security/selinux/netnode.c b/security/selinux/netnode.c
index 49c527799240..f3c526f2cacb 100644
--- a/security/selinux/netnode.c
+++ b/security/selinux/netnode.c
@@ -264,8 +264,12 @@ static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid)
 
 out:
         spin_unlock_bh(&sel_netnode_lock);
-        if (ret != 0)
+        if (unlikely(ret)) {
+                printk(KERN_WARNING
+                       "SELinux: failure in sel_netnode_sid_slow(),"
+                       " unable to determine network node label\n");
                 kfree(new);
+        }
         return ret;
 }