Commit fb5ae64f authored by Serge E. Hallyn's avatar Serge E. Hallyn Committed by Linus Torvalds

User namespaces: Only put the userns when we unhash the uid

uids in namespaces other than init don't get a sysfs entry.

For those in the init namespace, while we're waiting to remove
the sysfs entry for the uid the uid is still hashed, and
alloc_uid() may re-grab that uid without getting a new
reference to the user_ns, which we've already put in free_user
before scheduling remove_user_sysfs_dir().
Reported-and-tested-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarSerge E. Hallyn <serue@us.ibm.com>
Acked-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 37bed900
...@@ -72,6 +72,7 @@ static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent) ...@@ -72,6 +72,7 @@ static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
static void uid_hash_remove(struct user_struct *up) static void uid_hash_remove(struct user_struct *up)
{ {
hlist_del_init(&up->uidhash_node); hlist_del_init(&up->uidhash_node);
put_user_ns(up->user_ns);
} }
static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent) static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
...@@ -334,7 +335,6 @@ static void free_user(struct user_struct *up, unsigned long flags) ...@@ -334,7 +335,6 @@ static void free_user(struct user_struct *up, unsigned long flags)
atomic_inc(&up->__count); atomic_inc(&up->__count);
spin_unlock_irqrestore(&uidhash_lock, flags); spin_unlock_irqrestore(&uidhash_lock, flags);
put_user_ns(up->user_ns);
INIT_WORK(&up->work, remove_user_sysfs_dir); INIT_WORK(&up->work, remove_user_sysfs_dir);
schedule_work(&up->work); schedule_work(&up->work);
} }
...@@ -357,7 +357,6 @@ static void free_user(struct user_struct *up, unsigned long flags) ...@@ -357,7 +357,6 @@ static void free_user(struct user_struct *up, unsigned long flags)
sched_destroy_user(up); sched_destroy_user(up);
key_put(up->uid_keyring); key_put(up->uid_keyring);
key_put(up->session_keyring); key_put(up->session_keyring);
put_user_ns(up->user_ns);
kmem_cache_free(uid_cachep, up); kmem_cache_free(uid_cachep, up);
} }
......
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