-/* key.c: basic authentication token and access key management
+/* Basic authentication token and access key management
*
- * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
#include <linux/module.h>
#include <linux/init.h>
+#include <linux/poison.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <linux/workqueue.h>
+#include <linux/random.h>
#include <linux/err.h>
+#include <linux/user_namespace.h>
#include "internal.h"
-static kmem_cache_t *key_jar;
-static key_serial_t key_serial_next = 3;
+static struct kmem_cache *key_jar;
struct rb_root key_serial_tree; /* tree of keys indexed by serial */
DEFINE_SPINLOCK(key_serial_lock);
struct rb_root key_user_tree; /* tree of quota records indexed by UID */
DEFINE_SPINLOCK(key_user_lock);
+unsigned int key_quota_root_maxkeys = 200; /* root's key count quota */
+unsigned int key_quota_root_maxbytes = 20000; /* root's key space quota */
+unsigned int key_quota_maxkeys = 200; /* general key count quota */
+unsigned int key_quota_maxbytes = 20000; /* general key space quota */
+
static LIST_HEAD(key_types_list);
static DECLARE_RWSEM(key_types_sem);
-static void key_cleanup(void *data);
-static DECLARE_WORK(key_cleanup_task, key_cleanup, NULL);
+static void key_cleanup(struct work_struct *work);
+static DECLARE_WORK(key_cleanup_task, key_cleanup);
/* we serialise key instantiation and link */
-DECLARE_RWSEM(key_construction_sem);
+DEFINE_MUTEX(key_construction_mutex);
/* any key who's type gets unegistered will be re-typed to this */
-struct key_type key_type_dead = {
+static struct key_type key_type_dead = {
.name = "dead",
};
* get the key quota record for a user, allocating a new record if one doesn't
* already exist
*/
-struct key_user *key_user_lookup(uid_t uid)
+struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns)
{
struct key_user *candidate = NULL, *user;
struct rb_node *parent = NULL;
p = &(*p)->rb_left;
else if (uid > user->uid)
p = &(*p)->rb_right;
+ else if (user_ns < user->user_ns)
+ p = &(*p)->rb_left;
+ else if (user_ns > user->user_ns)
+ p = &(*p)->rb_right;
else
goto found;
}
atomic_set(&candidate->nkeys, 0);
atomic_set(&candidate->nikeys, 0);
candidate->uid = uid;
+ candidate->user_ns = get_user_ns(user_ns);
candidate->qnkeys = 0;
candidate->qnbytes = 0;
spin_lock_init(&candidate->lock);
- INIT_LIST_HEAD(&candidate->consq);
+ mutex_init(&candidate->cons_lock);
rb_link_node(&candidate->node, parent, p);
rb_insert_color(&candidate->node, &key_user_tree);
if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
rb_erase(&user->node, &key_user_tree);
spin_unlock(&key_user_lock);
+ put_user_ns(user->user_ns);
kfree(user);
}
/*****************************************************************************/
/*
- * insert a key with a fixed serial number
- */
-static void __init __key_insert_serial(struct key *key)
-{
- struct rb_node *parent, **p;
- struct key *xkey;
-
- parent = NULL;
- p = &key_serial_tree.rb_node;
-
- while (*p) {
- parent = *p;
- xkey = rb_entry(parent, struct key, serial_node);
-
- if (key->serial < xkey->serial)
- p = &(*p)->rb_left;
- else if (key->serial > xkey->serial)
- p = &(*p)->rb_right;
- else
- BUG();
- }
-
- /* we've found a suitable hole - arrange for this key to occupy it */
- rb_link_node(&key->serial_node, parent, p);
- rb_insert_color(&key->serial_node, &key_serial_tree);
-
-} /* end __key_insert_serial() */
-
-/*****************************************************************************/
-/*
* assign a key the next unique serial number
- * - we work through all the serial numbers between 2 and 2^31-1 in turn and
- * then wrap
+ * - these are assigned randomly to avoid security issues through covert
+ * channel problems
*/
static inline void key_alloc_serial(struct key *key)
{
struct rb_node *parent, **p;
struct key *xkey;
- spin_lock(&key_serial_lock);
-
- /* propose a likely serial number and look for a hole for it in the
+ /* propose a random serial number and look for a hole for it in the
* serial number tree */
- key->serial = key_serial_next;
- if (key->serial < 3)
- key->serial = 3;
- key_serial_next = key->serial + 1;
+ do {
+ get_random_bytes(&key->serial, sizeof(key->serial));
+ key->serial >>= 1; /* negative numbers are not permitted */
+ } while (key->serial < 3);
+
+ spin_lock(&key_serial_lock);
+
+attempt_insertion:
parent = NULL;
p = &key_serial_tree.rb_node;
else
goto serial_exists;
}
- goto insert_here;
+
+ /* we've found a suitable hole - arrange for this key to occupy it */
+ rb_link_node(&key->serial_node, parent, p);
+ rb_insert_color(&key->serial_node, &key_serial_tree);
+
+ spin_unlock(&key_serial_lock);
+ return;
/* we found a key with the proposed serial number - walk the tree from
* that point looking for the next unused serial number */
- serial_exists:
+serial_exists:
for (;;) {
- key->serial = key_serial_next;
- if (key->serial < 2)
- key->serial = 2;
- key_serial_next = key->serial + 1;
-
- if (!parent->rb_parent)
- p = &key_serial_tree.rb_node;
- else if (parent->rb_parent->rb_left == parent)
- p = &parent->rb_parent->rb_left;
- else
- p = &parent->rb_parent->rb_right;
+ key->serial++;
+ if (key->serial < 3) {
+ key->serial = 3;
+ goto attempt_insertion;
+ }
parent = rb_next(parent);
if (!parent)
- break;
+ goto attempt_insertion;
xkey = rb_entry(parent, struct key, serial_node);
if (key->serial < xkey->serial)
- goto insert_here;
+ goto attempt_insertion;
}
- /* we've found a suitable hole - arrange for this key to occupy it */
- insert_here:
- rb_link_node(&key->serial_node, parent, p);
- rb_insert_color(&key->serial_node, &key_serial_tree);
-
- spin_unlock(&key_serial_lock);
-
} /* end key_alloc_serial() */
/*****************************************************************************/
* instantiate the key or discard it before returning
*/
struct key *key_alloc(struct key_type *type, const char *desc,
- uid_t uid, gid_t gid, key_perm_t perm,
- int not_in_quota)
+ uid_t uid, gid_t gid, const struct cred *cred,
+ key_perm_t perm, unsigned long flags)
{
struct key_user *user = NULL;
struct key *key;
quotalen = desclen + type->def_datalen;
/* get hold of the key tracking for this user */
- user = key_user_lookup(uid);
+ user = key_user_lookup(uid, cred->user->user_ns);
if (!user)
goto no_memory_1;
/* check that the user's quota permits allocation of another key and
* its description */
- if (!not_in_quota) {
+ if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
+ unsigned maxkeys = (uid == 0) ?
+ key_quota_root_maxkeys : key_quota_maxkeys;
+ unsigned maxbytes = (uid == 0) ?
+ key_quota_root_maxbytes : key_quota_maxbytes;
+
spin_lock(&user->lock);
- if (user->qnkeys + 1 >= KEYQUOTA_MAX_KEYS &&
- user->qnbytes + quotalen >= KEYQUOTA_MAX_BYTES
- )
- goto no_quota;
+ if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
+ if (user->qnkeys + 1 >= maxkeys ||
+ user->qnbytes + quotalen >= maxbytes ||
+ user->qnbytes + quotalen < user->qnbytes)
+ goto no_quota;
+ }
user->qnkeys++;
user->qnbytes += quotalen;
}
/* allocate and initialise the key and its description */
- key = kmem_cache_alloc(key_jar, SLAB_KERNEL);
+ key = kmem_cache_alloc(key_jar, GFP_KERNEL);
if (!key)
goto no_memory_2;
if (desc) {
- key->description = kmalloc(desclen, GFP_KERNEL);
+ key->description = kmemdup(desc, desclen, GFP_KERNEL);
if (!key->description)
goto no_memory_3;
-
- memcpy(key->description, desc, desclen);
}
atomic_set(&key->usage, 1);
key->payload.data = NULL;
key->security = NULL;
- if (!not_in_quota)
+ if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
key->flags |= 1 << KEY_FLAG_IN_QUOTA;
memset(&key->type_data, 0, sizeof(key->type_data));
#endif
/* let the security module know about the key */
- ret = security_key_alloc(key);
+ ret = security_key_alloc(key, cred, flags);
if (ret < 0)
goto security_error;
security_error:
kfree(key->description);
kmem_cache_free(key_jar, key);
- if (!not_in_quota) {
+ if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
spin_lock(&user->lock);
user->qnkeys--;
user->qnbytes -= quotalen;
no_memory_3:
kmem_cache_free(key_jar, key);
no_memory_2:
- if (!not_in_quota) {
+ if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
spin_lock(&user->lock);
user->qnkeys--;
user->qnbytes -= quotalen;
/* contemplate the quota adjustment */
if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
+ unsigned maxbytes = (key->user->uid == 0) ?
+ key_quota_root_maxbytes : key_quota_maxbytes;
+
spin_lock(&key->user->lock);
if (delta > 0 &&
- key->user->qnbytes + delta > KEYQUOTA_MAX_BYTES
- ) {
+ (key->user->qnbytes + delta >= maxbytes ||
+ key->user->qnbytes + delta < key->user->qnbytes)) {
ret = -EDQUOT;
}
else {
const void *data,
size_t datalen,
struct key *keyring,
- struct key *instkey)
+ struct key *authkey)
{
int ret, awaken;
awaken = 0;
ret = -EBUSY;
- down_write(&key_construction_sem);
+ mutex_lock(&key_construction_mutex);
/* can't instantiate twice */
if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
ret = __key_link(keyring, key);
/* disable the authorisation key */
- if (instkey)
- key_revoke(instkey);
+ if (authkey)
+ key_revoke(authkey);
}
}
- up_write(&key_construction_sem);
+ mutex_unlock(&key_construction_mutex);
/* wake up anyone waiting for a key to be constructed */
if (awaken)
- wake_up_all(&request_key_conswq);
+ wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
return ret;
const void *data,
size_t datalen,
struct key *keyring,
- struct key *instkey)
+ struct key *authkey)
{
int ret;
if (keyring)
down_write(&keyring->sem);
- ret = __key_instantiate_and_link(key, data, datalen, keyring, instkey);
+ ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey);
if (keyring)
up_write(&keyring->sem);
int key_negate_and_link(struct key *key,
unsigned timeout,
struct key *keyring,
- struct key *instkey)
+ struct key *authkey)
{
struct timespec now;
int ret, awaken;
if (keyring)
down_write(&keyring->sem);
- down_write(&key_construction_sem);
+ mutex_lock(&key_construction_mutex);
/* can't instantiate twice */
if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
now = current_kernel_time();
key->expiry = now.tv_sec + timeout;
+ key_schedule_gc(key->expiry + key_gc_delay);
if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
awaken = 1;
ret = __key_link(keyring, key);
/* disable the authorisation key */
- if (instkey)
- key_revoke(instkey);
+ if (authkey)
+ key_revoke(authkey);
}
- up_write(&key_construction_sem);
+ mutex_unlock(&key_construction_mutex);
if (keyring)
up_write(&keyring->sem);
/* wake up anyone waiting for a key to be constructed */
if (awaken)
- wake_up_all(&request_key_conswq);
+ wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
return ret;
* do cleaning up in process context so that we don't have to disable
* interrupts all over the place
*/
-static void key_cleanup(void *data)
+static void key_cleanup(struct work_struct *work)
{
struct rb_node *_n;
struct key *key;
goto error;
found:
- /* pretend it doesn't exist if it's dead */
- if (atomic_read(&key->usage) == 0 ||
- test_bit(KEY_FLAG_DEAD, &key->flags) ||
- key->type == &key_type_dead)
+ /* pretend it doesn't exist if it is awaiting deletion */
+ if (atomic_read(&key->usage) == 0)
goto not_found;
/* this races with key_put(), but that doesn't matter since key_put()
const char *description,
const void *payload,
size_t plen,
- int not_in_quota)
+ key_perm_t perm,
+ unsigned long flags)
{
+ const struct cred *cred = current_cred();
struct key_type *ktype;
struct key *keyring, *key = NULL;
- key_perm_t perm;
key_ref_t key_ref;
int ret;
key_check(keyring);
+ key_ref = ERR_PTR(-ENOTDIR);
+ if (keyring->type != &key_type_keyring)
+ goto error_2;
+
down_write(&keyring->sem);
/* if we're going to allocate a new key, we're going to have
goto error_3;
}
- /* search for an existing key of the same type and description in the
- * destination keyring
+ /* if it's possible to update this type of key, search for an existing
+ * key of the same type and description in the destination keyring and
+ * update that instead if possible
*/
- key_ref = __keyring_search_one(keyring_ref, ktype, description, 0);
- if (!IS_ERR(key_ref))
- goto found_matching_key;
+ if (ktype->update) {
+ key_ref = __keyring_search_one(keyring_ref, ktype, description,
+ 0);
+ if (!IS_ERR(key_ref))
+ goto found_matching_key;
+ }
- /* decide on the permissions we want */
- perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
- perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR;
+ /* if the client doesn't provide, decide on the permissions we want */
+ if (perm == KEY_PERM_UNDEF) {
+ perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
+ perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR;
- if (ktype->read)
- perm |= KEY_POS_READ | KEY_USR_READ;
+ if (ktype->read)
+ perm |= KEY_POS_READ | KEY_USR_READ;
- if (ktype == &key_type_keyring || ktype->update)
- perm |= KEY_USR_WRITE;
+ if (ktype == &key_type_keyring || ktype->update)
+ perm |= KEY_USR_WRITE;
+ }
/* allocate a new key */
- key = key_alloc(ktype, description, current->fsuid, current->fsgid,
- perm, not_in_quota);
+ key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred,
+ perm, flags);
if (IS_ERR(key)) {
- key_ref = ERR_PTR(PTR_ERR(key));
+ key_ref = ERR_CAST(key);
goto error_3;
}
*/
void key_revoke(struct key *key)
{
+ struct timespec now;
+ time_t time;
+
key_check(key);
- /* make sure no one's trying to change or use the key when we mark
- * it */
- down_write(&key->sem);
- set_bit(KEY_FLAG_REVOKED, &key->flags);
+ /* make sure no one's trying to change or use the key when we mark it
+ * - we tell lockdep that we might nest because we might be revoking an
+ * authorisation key whilst holding the sem on a key we've just
+ * instantiated
+ */
+ down_write_nested(&key->sem, 1);
+ if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
+ key->type->revoke)
+ key->type->revoke(key);
+
+ /* set the death time to no more than the expiry time */
+ now = current_kernel_time();
+ time = now.tv_sec;
+ if (key->revoked_at == 0 || key->revoked_at > time) {
+ key->revoked_at = time;
+ key_schedule_gc(key->revoked_at + key_gc_delay);
+ }
+
up_write(&key->sem);
} /* end key_revoke() */
for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
key = rb_entry(_n, struct key, serial_node);
- if (key->type == ktype)
+ if (key->type == ktype) {
key->type = &key_type_dead;
+ set_bit(KEY_FLAG_DEAD, &key->flags);
+ }
}
spin_unlock(&key_serial_lock);
if (key->type == ktype) {
if (ktype->destroy)
ktype->destroy(key);
- memset(&key->payload, 0xbd, sizeof(key->payload));
+ memset(&key->payload, KEY_DESTROY, sizeof(key->payload));
}
}
spin_unlock(&key_serial_lock);
up_write(&key_types_sem);
+ key_schedule_gc(0);
+
} /* end unregister_key_type() */
EXPORT_SYMBOL(unregister_key_type);
{
/* allocate a slab in which we can store keys */
key_jar = kmem_cache_create("key_jar", sizeof(struct key),
- 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+ 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
/* add the special key types */
list_add_tail(&key_type_keyring.link, &key_types_list);
rb_insert_color(&root_key_user.node,
&key_user_tree);
- /* record root's user standard keyrings */
- key_check(&root_user_keyring);
- key_check(&root_session_keyring);
-
- __key_insert_serial(&root_user_keyring);
- __key_insert_serial(&root_session_keyring);
-
- keyring_publish_name(&root_user_keyring);
- keyring_publish_name(&root_session_keyring);
-
- /* link the two root keyrings together */
- key_link(&root_session_keyring, &root_user_keyring);
-
} /* end key_init() */