SELinux: use SECINITSID_NETMSG instead of SECINITSID_UNLABELED for NetLabel

These changes will make NetLabel behave like labeled IPsec where there is an
access check for both labeled and unlabeled packets as well as providing the
ability to restrict domains to receiving only labeled packets when NetLabel
is in use.  The changes to the policy are straight forward with the
following necessary to receive labeled traffic (with SECINITSID_NETMSG
defined as "netlabel_peer_t"):

 allow mydom_t netlabel_peer_t:{ tcp_socket udp_socket rawip_socket } recvfrom;

The policy for unlabeled traffic would be:

 allow mydom_t unlabeled_t:{ tcp_socket udp_socket rawip_socket } recvfrom;

These policy changes, as well as more general NetLabel support, are included
in the SELinux Reference Policy SVN tree, r2352 or later.  Users who enable
NetLabel support in the kernel are strongly encouraged to upgrade their
policy to avoid network problems.

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

1 files changed, 13 insertions, 21 deletions

diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index e64eca246f1a..8192e8bc9f5a 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -158,9 +158,7 @@ int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, u32 base_sid, u32 *sid)
         netlbl_secattr_init(&secattr);
         rc = netlbl_skbuff_getattr(skb, &secattr);
         if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
-                rc = security_netlbl_secattr_to_sid(&secattr,
-                                                    base_sid,
-                                                    sid);
+                rc = security_netlbl_secattr_to_sid(&secattr, base_sid, sid);
         else
                 *sid = SECSID_NULL;
         netlbl_secattr_destroy(&secattr);
@@ -198,7 +196,7 @@ void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock)
         if (netlbl_sock_getattr(sk, &secattr) == 0 &&
             secattr.flags != NETLBL_SECATTR_NONE &&
             security_netlbl_secattr_to_sid(&secattr,
-                                           SECINITSID_UNLABELED,
+                                           SECINITSID_NETMSG,
                                            &nlbl_peer_sid) == 0)
                 sksec->peer_sid = nlbl_peer_sid;
         netlbl_secattr_destroy(&secattr);
@@ -295,38 +293,32 @@ int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
                                 struct avc_audit_data *ad)
 {
         int rc;
-        u32 netlbl_sid;
-        u32 recv_perm;
+        u32 nlbl_sid;
+        u32 perm;
 
-        rc = selinux_netlbl_skbuff_getsid(skb,
-                                          SECINITSID_UNLABELED,
-                                          &netlbl_sid);
+        rc = selinux_netlbl_skbuff_getsid(skb, SECINITSID_NETMSG, &nlbl_sid);
         if (rc != 0)
                 return rc;
-
-        if (netlbl_sid == SECSID_NULL)
-                return 0;
+        if (nlbl_sid == SECSID_NULL)
+                nlbl_sid = SECINITSID_UNLABELED;
 
         switch (sksec->sclass) {
         case SECCLASS_UDP_SOCKET:
-                recv_perm = UDP_SOCKET__RECVFROM;
+                perm = UDP_SOCKET__RECVFROM;
                 break;
         case SECCLASS_TCP_SOCKET:
-                recv_perm = TCP_SOCKET__RECVFROM;
+                perm = TCP_SOCKET__RECVFROM;
                 break;
         default:
-                recv_perm = RAWIP_SOCKET__RECVFROM;
+                perm = RAWIP_SOCKET__RECVFROM;
         }
 
-        rc = avc_has_perm(sksec->sid,
-                          netlbl_sid,
-                          sksec->sclass,
-                          recv_perm,
-                          ad);
+        rc = avc_has_perm(sksec->sid, nlbl_sid, sksec->sclass, perm, ad);
         if (rc == 0)
                 return 0;
 
-        netlbl_skbuff_err(skb, rc);
+        if (nlbl_sid != SECINITSID_UNLABELED)
+                netlbl_skbuff_err(skb, rc);
         return rc;
 }