userns: Store uid and gid values in struct cred with kuid_t and kgid_t types

cred.h and a few trivial users of struct cred are changed.  The rest of the users
of struct cred are left for other patches as there are too many changes to make
in one go and leave the change reviewable.  If the user namespace is disabled and
CONFIG_UIDGID_STRICT_TYPE_CHECKS are disabled the code will contiue to compile
and behave correctly.

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

1 files changed, 9 insertions, 17 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index f0c43b4..3996281 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -175,7 +175,6 @@ SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 	const struct cred *cred = current_cred();
 	int error = -EINVAL;
 	struct pid *pgrp;
-	kuid_t cred_uid;
 	kuid_t uid;
 
 	if (which > PRIO_USER || which < PRIO_PROCESS)
@@ -209,22 +208,19 @@ SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 			break;
 		case PRIO_USER:
-			cred_uid = make_kuid(cred->user_ns, cred->uid);
 			uid = make_kuid(cred->user_ns, who);
 			user = cred->user;
 			if (!who)
-				uid = cred_uid;
-			else if (!uid_eq(uid, cred_uid) &&
+				uid = cred->uid;
+			else if (!uid_eq(uid, cred->uid) &&
 				 !(user = find_user(uid)))
 				goto out_unlock;	/* No processes for this user */
 
 			do_each_thread(g, p) {
-				const struct cred *tcred = __task_cred(p);
-				kuid_t tcred_uid = make_kuid(tcred->user_ns, tcred->uid);
-				if (uid_eq(tcred_uid, uid))
+				if (uid_eq(task_uid(p), uid))
 					error = set_one_prio(p, niceval, error);
 			} while_each_thread(g, p);
-			if (!uid_eq(uid, cred_uid))
+			if (!uid_eq(uid, cred->uid))
 				free_uid(user);		/* For find_user() */
 			break;
 	}
@@ -248,7 +244,6 @@ SYSCALL_DEFINE2(getpriority, int, which, int, who)
 	const struct cred *cred = current_cred();
 	long niceval, retval = -ESRCH;
 	struct pid *pgrp;
-	kuid_t cred_uid;
 	kuid_t uid;
 
 	if (which > PRIO_USER || which < PRIO_PROCESS)
@@ -280,25 +275,22 @@ SYSCALL_DEFINE2(getpriority, int, which, int, who)
 			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 			break;
 		case PRIO_USER:
-			cred_uid = make_kuid(cred->user_ns, cred->uid);
 			uid = make_kuid(cred->user_ns, who);
 			user = cred->user;
 			if (!who)
-				uid = cred_uid;
-			else if (!uid_eq(uid, cred_uid) &&
+				uid = cred->uid;
+			else if (!uid_eq(uid, cred->uid) &&
 				 !(user = find_user(uid)))
 				goto out_unlock;	/* No processes for this user */
 
 			do_each_thread(g, p) {
-				const struct cred *tcred = __task_cred(p);
-				kuid_t tcred_uid = make_kuid(tcred->user_ns, tcred->uid);
-				if (uid_eq(tcred_uid, uid)) {
+				if (uid_eq(task_uid(p), uid)) {
 					niceval = 20 - task_nice(p);
 					if (niceval > retval)
 						retval = niceval;
 				}
 			} while_each_thread(g, p);
-			if (!uid_eq(uid, cred_uid))
+			if (!uid_eq(uid, cred->uid))
 				free_uid(user);		/* for find_user() */
 			break;
 	}
@@ -641,7 +633,7 @@ static int set_user(struct cred *new)
 {
 	struct user_struct *new_user;
 
-	new_user = alloc_uid(make_kuid(new->user_ns, new->uid));
+	new_user = alloc_uid(new->uid);
 	if (!new_user)
 		return -EAGAIN;