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, 14 insertions, 4 deletions

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 0f1b9515213b..8e35e964d9ed 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -65,6 +65,7 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
         struct task_struct *p, *g;
         struct user_struct *user;
         struct pid *pgrp;
+        kuid_t uid;
         int ret;
 
         switch (class) {
@@ -110,16 +111,21 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
                         break;
                 case IOPRIO_WHO_USER:
+                        uid = make_kuid(current_user_ns(), who);
+                        if (!uid_valid(uid))
+                                break;
                         if (!who)
                                 user = current_user();
                         else
-                                user = find_user(who);
+                                user = find_user(uid);
 
                         if (!user)
                                 break;
 
                         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))
                                         continue;
                                 ret = set_task_ioprio(p, ioprio);
                                 if (ret)
@@ -174,6 +180,7 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
         struct task_struct *g, *p;
         struct user_struct *user;
         struct pid *pgrp;
+        kuid_t uid;
         int ret = -ESRCH;
         int tmpio;
 
@@ -203,16 +210,19 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
                         break;
                 case IOPRIO_WHO_USER:
+                        uid = make_kuid(current_user_ns(), who);
                         if (!who)
                                 user = current_user();
                         else
-                                user = find_user(who);
+                                user = find_user(uid);
 
                         if (!user)
                                 break;
 
                         do_each_thread(g, p) {
-                                if (__task_cred(p)->uid != user->uid)
+                                const struct cred *tcred = __task_cred(p);
+                                kuid_t tcred_uid = make_kuid(tcred->user_ns, tcred->uid);
+                                if (!uid_eq(tcred_uid, user->uid))
                                         continue;
                                 tmpio = get_task_ioprio(p);
                                 if (tmpio < 0)