userns: Use cred->user_ns instead of cred->user->user_ns

Optimize performance and prepare for the removal of the user_ns reference
from user_struct.  Remove the slow long walk through cred->user->user_ns and
instead go straight to cred->user_ns.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

4 files changed, 10 insertions, 10 deletions

diff --git a/security/commoncap.c b/security/commoncap.c
index 0cf4b53..8b3e10e 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -81,7 +81,7 @@ int cap_capable(const struct cred *cred, struct user_namespace *targ_ns,
 			return 0;
 
 		/* Do we have the necessary capabilities? */
-		if (targ_ns == cred->user->user_ns)
+		if (targ_ns == cred->user_ns)
 			return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM;
 
 		/* Have we tried all of the parent namespaces? */
@@ -136,10 +136,10 @@ int cap_ptrace_access_check(struct task_struct *child, unsigned int mode)
 	rcu_read_lock();
 	cred = current_cred();
 	child_cred = __task_cred(child);
-	if (cred->user->user_ns == child_cred->user->user_ns &&
+	if (cred->user_ns == child_cred->user_ns &&
 	    cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
 		goto out;
-	if (ns_capable(child_cred->user->user_ns, CAP_SYS_PTRACE))
+	if (ns_capable(child_cred->user_ns, CAP_SYS_PTRACE))
 		goto out;
 	ret = -EPERM;
 out:
@@ -168,10 +168,10 @@ int cap_ptrace_traceme(struct task_struct *parent)
 	rcu_read_lock();
 	cred = __task_cred(parent);
 	child_cred = current_cred();
-	if (cred->user->user_ns == child_cred->user->user_ns &&
+	if (cred->user_ns == child_cred->user_ns &&
 	    cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
 		goto out;
-	if (has_ns_capability(parent, child_cred->user->user_ns, CAP_SYS_PTRACE))
+	if (has_ns_capability(parent, child_cred->user_ns, CAP_SYS_PTRACE))
 		goto out;
 	ret = -EPERM;
 out:
@@ -214,7 +214,7 @@ static inline int cap_inh_is_capped(void)
 	/* they are so limited unless the current task has the CAP_SETPCAP
 	 * capability
 	 */
-	if (cap_capable(current_cred(), current_cred()->user->user_ns,
+	if (cap_capable(current_cred(), current_cred()->user_ns,
 			CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0)
 		return 0;
 	return 1;
@@ -866,7 +866,7 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 		    || ((new->securebits & SECURE_ALL_LOCKS & ~arg2))	/*[2]*/
 		    || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS))	/*[3]*/
 		    || (cap_capable(current_cred(),
-				    current_cred()->user->user_ns, CAP_SETPCAP,
+				    current_cred()->user_ns, CAP_SETPCAP,
 				    SECURITY_CAP_AUDIT) != 0)		/*[4]*/
 			/*
 			 * [1] no changing of bits that are locked
diff --git a/security/keys/key.c b/security/keys/key.c
index 06783cf..7e60347 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -253,7 +253,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
 	quotalen = desclen + type->def_datalen;
 
 	/* get hold of the key tracking for this user */
-	user = key_user_lookup(uid, cred->user->user_ns);
+	user = key_user_lookup(uid, cred->user_ns);
 	if (!user)
 		goto no_memory_1;
 
diff --git a/security/keys/permission.c b/security/keys/permission.c
index c35b522..e146cbd 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -36,7 +36,7 @@ int key_task_permission(const key_ref_t key_ref, const struct cred *cred,
 
 	key = key_ref_to_ptr(key_ref);
 
-	if (key->user->user_ns != cred->user->user_ns)
+	if (key->user->user_ns != cred->user_ns)
 		goto use_other_perms;
 
 	/* use the second 8-bits of permissions for keys the caller owns */
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index be7ecb2..70febff 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -858,7 +858,7 @@ void key_replace_session_keyring(void)
 	new-> sgid	= old-> sgid;
 	new->fsgid	= old->fsgid;
 	new->user	= get_uid(old->user);
-	new->user_ns	= new->user->user_ns;
+	new->user_ns	= new->user_ns;
 	new->group_info	= get_group_info(old->group_info);
 
 	new->securebits	= old->securebits;