userns: Disassociate user_struct from the user_namespace.

Modify alloc_uid to take a kuid and make the user hash table global.
Stop holding a reference to the user namespace in struct user_struct.

This simplifies the code and makes the per user accounting not
care about which user namespace a uid happens to appear in.

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

1 files changed, 23 insertions, 11 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index 7185241..f0c43b4 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -175,6 +175,8 @@ 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)
 		goto out;
@@ -207,18 +209,22 @@ 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)
-				who = cred->uid;
-			else if ((who != cred->uid) &&
-				 !(user = find_user(who)))
+				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) {
-				if (__task_cred(p)->uid == who)
+				const struct cred *tcred = __task_cred(p);
+				kuid_t tcred_uid = make_kuid(tcred->user_ns, tcred->uid);
+				if (uid_eq(tcred_uid, uid))
 					error = set_one_prio(p, niceval, error);
 			} while_each_thread(g, p);
-			if (who != cred->uid)
+			if (!uid_eq(uid, cred_uid))
 				free_uid(user);		/* For find_user() */
 			break;
 	}
@@ -242,6 +248,8 @@ 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)
 		return -EINVAL;
@@ -272,21 +280,25 @@ 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)
-				who = cred->uid;
-			else if ((who != cred->uid) &&
-				 !(user = find_user(who)))
+				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) {
-				if (__task_cred(p)->uid == who) {
+				const struct cred *tcred = __task_cred(p);
+				kuid_t tcred_uid = make_kuid(tcred->user_ns, tcred->uid);
+				if (uid_eq(tcred_uid, uid)) {
 					niceval = 20 - task_nice(p);
 					if (niceval > retval)
 						retval = niceval;
 				}
 			} while_each_thread(g, p);
-			if (who != cred->uid)
+			if (!uid_eq(uid, cred_uid))
 				free_uid(user);		/* for find_user() */
 			break;
 	}
@@ -629,7 +641,7 @@ static int set_user(struct cred *new)
 {
 	struct user_struct *new_user;
 
-	new_user = alloc_uid(current_user_ns(), new->uid);
+	new_user = alloc_uid(make_kuid(new->user_ns, new->uid));
 	if (!new_user)
 		return -EAGAIN;