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/request_key.c b/security/keys/request_key.c
index ac49c8a..f656e9c 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -299,6 +299,7 @@
struct key_user *user,
struct key **_key)
{
+ struct keyring_list *prealloc;
const struct cred *cred = current_cred();
struct key *key;
key_ref_t key_ref;
@@ -306,6 +307,7 @@
kenter("%s,%s,,,", type->name, description);
+ *_key = NULL;
mutex_lock(&user->cons_lock);
key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
@@ -315,8 +317,12 @@
set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
- if (dest_keyring)
- down_write(&dest_keyring->sem);
+ if (dest_keyring) {
+ ret = __key_link_begin(dest_keyring, type, description,
+ &prealloc);
+ if (ret < 0)
+ goto link_prealloc_failed;
+ }
/* attach the key to the destination keyring under lock, but we do need
* to do another check just in case someone beat us to it whilst we
@@ -328,11 +334,11 @@
goto key_already_present;
if (dest_keyring)
- __key_link(dest_keyring, key);
+ __key_link(dest_keyring, key, &prealloc);
mutex_unlock(&key_construction_mutex);
if (dest_keyring)
- up_write(&dest_keyring->sem);
+ __key_link_end(dest_keyring, type, prealloc);
mutex_unlock(&user->cons_lock);
*_key = key;
kleave(" = 0 [%d]", key_serial(key));
@@ -341,27 +347,36 @@
/* the key is now present - we tell the caller that we found it by
* returning -EINPROGRESS */
key_already_present:
+ key_put(key);
mutex_unlock(&key_construction_mutex);
- ret = 0;
+ key = key_ref_to_ptr(key_ref);
if (dest_keyring) {
- ret = __key_link(dest_keyring, key_ref_to_ptr(key_ref));
- up_write(&dest_keyring->sem);
+ ret = __key_link_check_live_key(dest_keyring, key);
+ if (ret == 0)
+ __key_link(dest_keyring, key, &prealloc);
+ __key_link_end(dest_keyring, type, prealloc);
+ if (ret < 0)
+ goto link_check_failed;
}
mutex_unlock(&user->cons_lock);
- key_put(key);
- if (ret < 0) {
- key_ref_put(key_ref);
- *_key = NULL;
- kleave(" = %d [link]", ret);
- return ret;
- }
- *_key = key = key_ref_to_ptr(key_ref);
+ *_key = key;
kleave(" = -EINPROGRESS [%d]", key_serial(key));
return -EINPROGRESS;
+link_check_failed:
+ mutex_unlock(&user->cons_lock);
+ key_put(key);
+ kleave(" = %d [linkcheck]", ret);
+ return ret;
+
+link_prealloc_failed:
+ up_write(&dest_keyring->sem);
+ mutex_unlock(&user->cons_lock);
+ kleave(" = %d [prelink]", ret);
+ return ret;
+
alloc_failed:
mutex_unlock(&user->cons_lock);
- *_key = NULL;
kleave(" = %ld", PTR_ERR(key));
return PTR_ERR(key);
}