diff options
Diffstat (limited to 'kernel/user.c')
-rw-r--r-- | kernel/user.c | 61 |
1 files changed, 41 insertions, 20 deletions
diff --git a/kernel/user.c b/kernel/user.c index 4869563080e9..9ca2848fc356 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -14,20 +14,19 @@ #include <linux/bitops.h> #include <linux/key.h> #include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/user_namespace.h> /* * UID task count cache, to get fast user lookup in "alloc_uid" * when changing user ID's (ie setuid() and friends). */ -#define UIDHASH_BITS (CONFIG_BASE_SMALL ? 3 : 8) -#define UIDHASH_SZ (1 << UIDHASH_BITS) #define UIDHASH_MASK (UIDHASH_SZ - 1) #define __uidhashfn(uid) (((uid >> UIDHASH_BITS) + uid) & UIDHASH_MASK) -#define uidhashentry(uid) (uidhash_table + __uidhashfn((uid))) +#define uidhashentry(ns, uid) ((ns)->uidhash_table + __uidhashfn((uid))) static struct kmem_cache *uid_cachep; -static struct list_head uidhash_table[UIDHASH_SZ]; /* * The uidhash_lock is mostly taken from process context, but it is @@ -56,25 +55,22 @@ struct user_struct root_user = { /* * These routines must be called with the uidhash spinlock held! */ -static inline void uid_hash_insert(struct user_struct *up, struct list_head *hashent) +static inline void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent) { - list_add(&up->uidhash_list, hashent); + hlist_add_head(&up->uidhash_node, hashent); } static inline void uid_hash_remove(struct user_struct *up) { - list_del(&up->uidhash_list); + hlist_del_init(&up->uidhash_node); } -static inline struct user_struct *uid_hash_find(uid_t uid, struct list_head *hashent) +static inline struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent) { - struct list_head *up; - - list_for_each(up, hashent) { - struct user_struct *user; - - user = list_entry(up, struct user_struct, uidhash_list); + struct user_struct *user; + struct hlist_node *h; + hlist_for_each_entry(user, h, hashent, uidhash_node) { if(user->uid == uid) { atomic_inc(&user->__count); return user; @@ -94,9 +90,10 @@ struct user_struct *find_user(uid_t uid) { struct user_struct *ret; unsigned long flags; + struct user_namespace *ns = current->nsproxy->user_ns; spin_lock_irqsave(&uidhash_lock, flags); - ret = uid_hash_find(uid, uidhashentry(uid)); + ret = uid_hash_find(uid, uidhashentry(ns, uid)); spin_unlock_irqrestore(&uidhash_lock, flags); return ret; } @@ -120,9 +117,9 @@ void free_uid(struct user_struct *up) } } -struct user_struct * alloc_uid(uid_t uid) +struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid) { - struct list_head *hashent = uidhashentry(uid); + struct hlist_head *hashent = uidhashentry(ns, uid); struct user_struct *up; spin_lock_irq(&uidhash_lock); @@ -202,20 +199,44 @@ void switch_uid(struct user_struct *new_user) suid_keys(current); } +void release_uids(struct user_namespace *ns) +{ + int i; + unsigned long flags; + struct hlist_head *head; + struct hlist_node *nd; + + spin_lock_irqsave(&uidhash_lock, flags); + /* + * collapse the chains so that the user_struct-s will + * be still alive, but not in hashes. subsequent free_uid() + * will free them. + */ + for (i = 0; i < UIDHASH_SZ; i++) { + head = ns->uidhash_table + i; + while (!hlist_empty(head)) { + nd = head->first; + hlist_del_init(nd); + } + } + spin_unlock_irqrestore(&uidhash_lock, flags); + + free_uid(ns->root_user); +} static int __init uid_cache_init(void) { int n; uid_cachep = kmem_cache_create("uid_cache", sizeof(struct user_struct), - 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); + 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); for(n = 0; n < UIDHASH_SZ; ++n) - INIT_LIST_HEAD(uidhash_table + n); + INIT_HLIST_HEAD(init_user_ns.uidhash_table + n); /* Insert the root user immediately (init already runs as root) */ spin_lock_irq(&uidhash_lock); - uid_hash_insert(&root_user, uidhashentry(0)); + uid_hash_insert(&root_user, uidhashentry(&init_user_ns, 0)); spin_unlock_irq(&uidhash_lock); return 0; |