[RFC PATCH 14/27] keys: Break bits out of key_unlink()

David Howells
2019-02-15T16:09:44Z

Break bits out of key_unlink() into helper functions so that they can be
used in implementing key_move().

Signed-off-by: David Howells <dhowells@redhat.com>
---

security/keys/keyring.c | 89 +++++++++++++++++++++++++++++++++++------------
1 file changed, 66 insertions(+), 23 deletions(-)

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 062cad635edf..431094c6cd74 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -1409,6 +1409,66 @@ int key_link(struct key *keyring, struct key *key)
}
EXPORT_SYMBOL(key_link);

+/*
+ * Begin the process of unlinking a key from a keyring.
+ */
+static int __key_unlink_begin(struct key *keyring, unsigned int lock_nesting,
+ struct key *key, struct assoc_array_edit **_edit)
+ __acquires(&keyring->sem)
+{
+ struct assoc_array_edit *edit;
+ int ret;
+
+ if (keyring->type != &key_type_keyring)
+ return -ENOTDIR;
+
+ down_write_nested(&keyring->sem, lock_nesting);
+
+ edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops,
+ &key->index_key);
+ if (IS_ERR(edit)) {
+ ret = PTR_ERR(edit);
+ goto error;
+ }
+
+ if (!edit) {
+ ret = -ENOENT;
+ goto error;
+ }
+
+ *_edit = edit;
+ return 0;
+
+error:
+ up_write(&keyring->sem);
+ return ret;
+}
+
+/*
+ * Apply an unlink change.
+ */
+static void __key_unlink(struct key *keyring, struct key *key,
+ struct assoc_array_edit **_edit)
+{
+ assoc_array_apply_edit(*_edit);
+ *_edit = NULL;
+ notify_key(keyring, NOTIFY_KEY_UNLINKED, key_serial(key));
+ key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES);
+}
+
+/*
+ * Finish unlinking a key from to a keyring.
+ */
+static void __key_unlink_end(struct key *keyring,
+ struct key *key,
+ struct assoc_array_edit *edit)
+ __releases(&keyring->sem)
+{
+ if (edit)
+ assoc_array_cancel_edit(edit);
+ up_write(&keyring->sem);
+}
+
/**
* key_unlink - Unlink the first link to a key from a keyring.
* @keyring: The keyring to remove the link from.
@@ -1429,35 +1489,18 @@ EXPORT_SYMBOL(key_link);
int key_unlink(struct key *keyring, struct key *key)
{
struct assoc_array_edit *edit;
- key_serial_t target = key_serial(key);
int ret;

key_check(keyring);
key_check(key);

- if (keyring->type != &key_type_keyring)
- return -ENOTDIR;
-
- down_write(&keyring->sem);
-
- edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops,
- &key->index_key);
- if (IS_ERR(edit)) {
- ret = PTR_ERR(edit);
- goto error;
- }
- ret = -ENOENT;
- if (edit == NULL)
- goto error;
-
- assoc_array_apply_edit(edit);
- notify_key(keyring, NOTIFY_KEY_UNLINKED, target);
- key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES);
- ret = 0;
+ ret = __key_unlink_begin(keyring, 0, key, &edit);
+ if (ret < 0)
+ return ret;

-error:
- up_write(&keyring->sem);
- return ret;
+ __key_unlink(keyring, key, &edit);
+ __key_unlink_end(keyring, key, edit);
+ return 0;
}
EXPORT_SYMBOL(key_unlink);