KEYS: Do preallocation for __key_link()
Do preallocation for __key_link() so that the various callers in request_key.c
can deal with any errors from this source before attempting to construct a key.
This allows them to assume that the actual linkage step is guaranteed to be
successful.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/keys/key.c b/security/keys/key.c
index c70da6f..c1eac80 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -398,7 +398,8 @@
const void *data,
size_t datalen,
struct key *keyring,
- struct key *authkey)
+ struct key *authkey,
+ struct keyring_list **_prealloc)
{
int ret, awaken;
@@ -425,7 +426,7 @@
/* and link it into the destination keyring */
if (keyring)
- ret = __key_link(keyring, key);
+ __key_link(keyring, key, _prealloc);
/* disable the authorisation key */
if (authkey)
@@ -453,15 +454,21 @@
struct key *keyring,
struct key *authkey)
{
+ struct keyring_list *prealloc;
int ret;
- if (keyring)
- down_write(&keyring->sem);
+ if (keyring) {
+ ret = __key_link_begin(keyring, key->type, key->description,
+ &prealloc);
+ if (ret < 0)
+ return ret;
+ }
- ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey);
+ ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey,
+ &prealloc);
if (keyring)
- up_write(&keyring->sem);
+ __key_link_end(keyring, key->type, prealloc);
return ret;
@@ -478,8 +485,9 @@
struct key *keyring,
struct key *authkey)
{
+ struct keyring_list *prealloc;
struct timespec now;
- int ret, awaken;
+ int ret, awaken, link_ret = 0;
key_check(key);
key_check(keyring);
@@ -488,7 +496,8 @@
ret = -EBUSY;
if (keyring)
- down_write(&keyring->sem);
+ link_ret = __key_link_begin(keyring, key->type,
+ key->description, &prealloc);
mutex_lock(&key_construction_mutex);
@@ -508,8 +517,8 @@
ret = 0;
/* and link it into the destination keyring */
- if (keyring)
- ret = __key_link(keyring, key);
+ if (keyring && link_ret == 0)
+ __key_link(keyring, key, &prealloc);
/* disable the authorisation key */
if (authkey)
@@ -519,13 +528,13 @@
mutex_unlock(&key_construction_mutex);
if (keyring)
- up_write(&keyring->sem);
+ __key_link_end(keyring, key->type, prealloc);
/* wake up anyone waiting for a key to be constructed */
if (awaken)
wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
- return ret;
+ return ret == 0 ? link_ret : ret;
} /* end key_negate_and_link() */
@@ -749,6 +758,7 @@
key_perm_t perm,
unsigned long flags)
{
+ struct keyring_list *prealloc;
const struct cred *cred = current_cred();
struct key_type *ktype;
struct key *keyring, *key = NULL;
@@ -775,7 +785,9 @@
if (keyring->type != &key_type_keyring)
goto error_2;
- down_write(&keyring->sem);
+ ret = __key_link_begin(keyring, ktype, description, &prealloc);
+ if (ret < 0)
+ goto error_2;
/* if we're going to allocate a new key, we're going to have
* to modify the keyring */
@@ -817,7 +829,8 @@
}
/* instantiate it and link it into the target keyring */
- ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL);
+ ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL,
+ &prealloc);
if (ret < 0) {
key_put(key);
key_ref = ERR_PTR(ret);
@@ -827,7 +840,7 @@
key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
error_3:
- up_write(&keyring->sem);
+ __key_link_end(keyring, ktype, prealloc);
error_2:
key_type_put(ktype);
error:
@@ -837,7 +850,7 @@
/* we found a matching key, so we're going to try to update it
* - we can drop the locks first as we have the key pinned
*/
- up_write(&keyring->sem);
+ __key_link_end(keyring, ktype, prealloc);
key_type_put(ktype);
key_ref = __key_update(key_ref, payload, plen);