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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
  KEYS: call_sbin_request_key() must write lock keyrings before modifying them
  KEYS: Use RCU dereference wrappers in keyring key type code
  KEYS: find_keyring_by_name() can gain access to a freed keyring
This commit is contained in:
Linus Torvalds 2010-05-05 09:06:24 -07:00
parent 8777c793d6 896903c2f5
commit 5f23370659
2 changed files with 23 additions and 20 deletions
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41
security/keys/keyring.c
View File

@ -20,6 +20,11 @@
#include <asm/uaccess.h>
#include "internal.h"
#define rcu_dereference_locked_keyring(keyring) \
(rcu_dereference_protected( \
(keyring)->payload.subscriptions, \
rwsem_is_locked((struct rw_semaphore *)&(keyring)->sem)))
/*
* when plumbing the depths of the key tree, this sets a hard limit set on how
* deep we're willing to go
@ -201,8 +206,7 @@ static long keyring_read(const struct key *keyring,
int loop, ret;
ret = 0;
klist = keyring->payload.subscriptions;
klist = rcu_dereference_locked_keyring(keyring);
if (klist) {
/* calculate how much data we could return */
qty = klist->nkeys * sizeof(key_serial_t);
@ -526,9 +530,8 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
struct key *keyring;
int bucket;
keyring = ERR_PTR(-EINVAL);
if (!name)
goto error;
return ERR_PTR(-EINVAL);
bucket = keyring_hash(name);
@ -555,17 +558,18 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
KEY_SEARCH) < 0)
continue;
/* we've got a match */
atomic_inc(&keyring->usage);
read_unlock(&keyring_name_lock);
goto error;
/* we've got a match but we might end up racing with
* key_cleanup() if the keyring is currently 'dead'
* (ie. it has a zero usage count) */
if (!atomic_inc_not_zero(&keyring->usage))
continue;
goto out;
}
}
read_unlock(&keyring_name_lock);
keyring = ERR_PTR(-ENOKEY);
error:
out:
read_unlock(&keyring_name_lock);
return keyring;
} /* end find_keyring_by_name() */
@ -720,8 +724,7 @@ int __key_link(struct key *keyring, struct key *key)
}
/* see if there's a matching key we can displace */
klist = keyring->payload.subscriptions;
klist = rcu_dereference_locked_keyring(keyring);
if (klist && klist->nkeys > 0) {
struct key_type *type = key->type;
@ -765,8 +768,6 @@ int __key_link(struct key *keyring, struct key *key)
if (ret < 0)
goto error2;
klist = keyring->payload.subscriptions;
if (klist && klist->nkeys < klist->maxkeys) {
/* there's sufficient slack space to add directly */
atomic_inc(&key->usage);
@ -868,7 +869,7 @@ int key_unlink(struct key *keyring, struct key *key)
down_write(&keyring->sem);
klist = keyring->payload.subscriptions;
klist = rcu_dereference_locked_keyring(keyring);
if (klist) {
/* search the keyring for the key */
for (loop = 0; loop < klist->nkeys; loop++)
@ -959,7 +960,7 @@ int keyring_clear(struct key *keyring)
/* detach the pointer block with the locks held */
down_write(&keyring->sem);
klist = keyring->payload.subscriptions;
klist = rcu_dereference_locked_keyring(keyring);
if (klist) {
/* adjust the quota */
key_payload_reserve(keyring,
@ -991,7 +992,9 @@ EXPORT_SYMBOL(keyring_clear);
*/
static void keyring_revoke(struct key *keyring)
{
struct keyring_list *klist = keyring->payload.subscriptions;
struct keyring_list *klist;
klist = rcu_dereference_locked_keyring(keyring);
/* adjust the quota */
key_payload_reserve(keyring, 0);
@ -1025,7 +1028,7 @@ void keyring_gc(struct key *keyring, time_t limit)
down_write(&keyring->sem);
klist = keyring->payload.subscriptions;
klist = rcu_dereference_locked_keyring(keyring);
if (!klist)
goto no_klist;

2
security/keys/request_key.c
View File

@ -94,7 +94,7 @@ static int call_sbin_request_key(struct key_construction *cons,
}
/* attach the auth key to the session keyring */
ret = __key_link(keyring, authkey);
ret = key_link(keyring, authkey);
if (ret < 0)
goto error_link;