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 71852417cfc8..f0c43b4b6657 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;