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Commit 8b6a666a authored by David Howells's avatar David Howells
Browse files

afs: Provide an RCU-capable key lookup 



Provide an RCU-capable key lookup function.  We don't want to call
afs_request_key() in RCU-mode pathwalk as request_key() might sleep, even if
we don't ask it to construct anything as it might find a key that is currently
undergoing construction.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 23a28913

fs/afs/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -1217,6 +1217,7 @@ extern void afs_cache_permit(struct afs_vnode *, struct key *, unsigned int, 
			     struct afs_status_cb *);

extern void afs_zap_permits(struct rcu_head *);

extern struct key *afs_request_key(struct afs_cell *);

extern struct key *afs_request_key_rcu(struct afs_cell *);

extern int afs_check_permit(struct afs_vnode *, struct key *, afs_access_t *);

extern int afs_permission(struct inode *, int);

extern void __exit afs_clean_up_permit_cache(void);

fs/afs/security.c

+31 −2
Original line number Diff line number Diff line
@@ -27,8 +27,37 @@ struct key *afs_request_key(struct afs_cell *cell) 
	_enter("{%x}", key_serial(cell->anonymous_key));



	_debug("key %s", cell->anonymous_key->description);

	key = request_key(&key_type_rxrpc, cell->anonymous_key->description,

			  NULL);

	key = request_key_net(&key_type_rxrpc, cell->anonymous_key->description,

			      cell->net->net, NULL);

	if (IS_ERR(key)) {

		if (PTR_ERR(key) != -ENOKEY) {

			_leave(" = %ld", PTR_ERR(key));

			return key;

		}



		/* act as anonymous user */

		_leave(" = {%x} [anon]", key_serial(cell->anonymous_key));

		return key_get(cell->anonymous_key);

	} else {

		/* act as authorised user */

		_leave(" = {%x} [auth]", key_serial(key));

		return key;

	}

}



/*

 * Get a key when pathwalk is in rcuwalk mode.

 */

struct key *afs_request_key_rcu(struct afs_cell *cell)

{

	struct key *key;



	_enter("{%x}", key_serial(cell->anonymous_key));



	_debug("key %s", cell->anonymous_key->description);

	key = request_key_net_rcu(&key_type_rxrpc,

				  cell->anonymous_key->description,

				  cell->net->net);

	if (IS_ERR(key)) {

		if (PTR_ERR(key) != -ENOKEY) {

			_leave(" = %ld", PTR_ERR(key));

include/linux/key.h

+13 −1
Original line number Diff line number Diff line
@@ -324,7 +324,7 @@ static inline struct key *request_key(struct key_type *type, 
}



#ifdef CONFIG_NET

/*

/**

 * request_key_net - Request a key for a net namespace and wait for construction

 * @type: Type of key.

 * @description: The searchable description of the key.
@@ -341,6 +341,18 @@ static inline struct key *request_key(struct key_type *type, 
 */

#define request_key_net(type, description, net, callout_info) \

	request_key_tag(type, description, net->key_domain, callout_info);



/**

 * request_key_net_rcu - Request a key for a net namespace under RCU conditions

 * @type: Type of key.

 * @description: The searchable description of the key.

 * @net: The network namespace that is the key's domain of operation.

 *

 * As for request_key_rcu() except that only keys that operate the specified

 * network namespace are used.

 */

#define request_key_net_rcu(type, description, net) \

	request_key_rcu(type, description, net->key_domain);

#endif /* CONFIG_NET */



extern int wait_for_key_construction(struct key *key, bool intr);