SELinux: Allow NetLabel to directly cache SIDs

Now that the SELinux NetLabel "base SID" is always the netmsg initial SID we
can do a big optimization - caching the SID and not just the MLS attributes.
This not only saves a lot of per-packet memory allocations and copies but it
has a nice side effect of removing a chunk of code.

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

1 files changed, 34 insertions, 21 deletions

diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index b54d28fd3b5d..0fa2be4149e8 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -36,6 +36,33 @@
 #include "security.h"
 
 /**
+ * selinux_netlbl_sidlookup_cached - Cache a SID lookup
+ * @skb: the packet
+ * @secattr: the NetLabel security attributes
+ * @sid: the SID
+ *
+ * Description:
+ * Query the SELinux security server to lookup the correct SID for the given
+ * security attributes.  If the query is successful, cache the result to speed
+ * up future lookups.  Returns zero on success, negative values on failure.
+ *
+ */
+static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
+                                           struct netlbl_lsm_secattr *secattr,
+                                           u32 *sid)
+{
+        int rc;
+
+        rc = security_netlbl_secattr_to_sid(secattr, sid);
+        if (rc == 0 &&
+            (secattr->flags & NETLBL_SECATTR_CACHEABLE) &&
+            (secattr->flags & NETLBL_SECATTR_CACHE))
+                netlbl_cache_add(skb, secattr);
+
+        return rc;
+}
+
+/**
  * selinux_netlbl_sock_setsid - Label a socket using the NetLabel mechanism
  * @sk: the socket to label
  * @sid: the SID to use
@@ -144,7 +171,6 @@ void selinux_netlbl_sk_security_clone(struct sk_security_struct *ssec,
  * selinux_netlbl_skbuff_getsid - Get the sid of a packet using NetLabel
  * @skb: the packet
  * @family: protocol family
- * @base_sid: the SELinux SID to use as a context for MLS only attributes
  * @type: NetLabel labeling protocol type
  * @sid: the SID
  *
@@ -156,7 +182,6 @@ void selinux_netlbl_sk_security_clone(struct sk_security_struct *ssec,
  */
 int selinux_netlbl_skbuff_getsid(struct sk_buff *skb,
                                  u16 family,
-                                 u32 base_sid,
                                  u32 *type,
                                  u32 *sid)
 {
@@ -170,13 +195,9 @@ int selinux_netlbl_skbuff_getsid(struct sk_buff *skb,
 
         netlbl_secattr_init(&secattr);
         rc = netlbl_skbuff_getattr(skb, family, &secattr);
-        if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) {
-                rc = security_netlbl_secattr_to_sid(&secattr, base_sid, sid);
-                if (rc == 0 &&
-                    (secattr.flags & NETLBL_SECATTR_CACHEABLE) &&
-                    (secattr.flags & NETLBL_SECATTR_CACHE))
-                        netlbl_cache_add(skb, &secattr);
-        } else
+        if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
+                rc = selinux_netlbl_sidlookup_cached(skb, &secattr, sid);
+        else
                 *sid = SECSID_NULL;
         *type = secattr.type;
         netlbl_secattr_destroy(&secattr);
@@ -210,9 +231,7 @@ void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock)
         netlbl_secattr_init(&secattr);
         if (netlbl_sock_getattr(sk, &secattr) == 0 &&
             secattr.flags != NETLBL_SECATTR_NONE &&
-            security_netlbl_secattr_to_sid(&secattr,
-                                           SECINITSID_NETMSG,
-                                           &nlbl_peer_sid) == 0)
+            security_netlbl_secattr_to_sid(&secattr, &nlbl_peer_sid) == 0)
                 sksec->peer_sid = nlbl_peer_sid;
         netlbl_secattr_destroy(&secattr);
 
@@ -316,15 +335,9 @@ int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
 
         netlbl_secattr_init(&secattr);
         rc = netlbl_skbuff_getattr(skb, family, &secattr);
-        if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) {
-                rc = security_netlbl_secattr_to_sid(&secattr,
-                                                    SECINITSID_NETMSG,
-                                                    &nlbl_sid);
-                if (rc == 0 &&
-                    (secattr.flags & NETLBL_SECATTR_CACHEABLE) &&
-                    (secattr.flags & NETLBL_SECATTR_CACHE))
-                        netlbl_cache_add(skb, &secattr);
-        } else
+        if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
+                rc = selinux_netlbl_sidlookup_cached(skb, &secattr, &nlbl_sid);
+        else
                 nlbl_sid = SECINITSID_UNLABELED;
         netlbl_secattr_destroy(&secattr);
         if (rc != 0)