CRED: Wrap task credential accesses in the networking subsystem

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: netdev@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/net/core/dev.c b/net/core/dev.c
index d9038e3..262df22 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2958,6 +2958,8 @@
 static int __dev_set_promiscuity(struct net_device *dev, int inc)
 {
 	unsigned short old_flags = dev->flags;
+	uid_t uid;
+	gid_t gid;
 
 	ASSERT_RTNL();
 
@@ -2982,15 +2984,17 @@
 		printk(KERN_INFO "device %s %s promiscuous mode\n",
 		       dev->name, (dev->flags & IFF_PROMISC) ? "entered" :
 							       "left");
-		if (audit_enabled)
+		if (audit_enabled) {
+			current_uid_gid(&uid, &gid);
 			audit_log(current->audit_context, GFP_ATOMIC,
 				AUDIT_ANOM_PROMISCUOUS,
 				"dev=%s prom=%d old_prom=%d auid=%u uid=%u gid=%u ses=%u",
 				dev->name, (dev->flags & IFF_PROMISC),
 				(old_flags & IFF_PROMISC),
 				audit_get_loginuid(current),
-				current->uid, current->gid,
+				uid, gid,
 				audit_get_sessionid(current));
+		}
 
 		dev_change_rx_flags(dev, IFF_PROMISC);
 	}
diff --git a/net/core/scm.c b/net/core/scm.c
index 10f5c65..4681d8f 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -45,10 +45,10 @@
 static __inline__ int scm_check_creds(struct ucred *creds)
 {
 	if ((creds->pid == task_tgid_vnr(current) || capable(CAP_SYS_ADMIN)) &&
-	    ((creds->uid == current->uid || creds->uid == current->euid ||
-	      creds->uid == current->suid) || capable(CAP_SETUID)) &&
-	    ((creds->gid == current->gid || creds->gid == current->egid ||
-	      creds->gid == current->sgid) || capable(CAP_SETGID))) {
+	    ((creds->uid == current_uid()   || creds->uid == current_euid() ||
+	      creds->uid == current_suid()) || capable(CAP_SETUID)) &&
+	    ((creds->gid == current_gid()   || creds->gid == current_egid() ||
+	      creds->gid == current_sgid()) || capable(CAP_SETGID))) {
 	       return 0;
 	}
 	return -EPERM;