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authorDavid Howells <dhowells@redhat.com>2019-05-20 08:48:46 +0100
committerDavid Howells <dhowells@redhat.com>2019-09-02 11:43:54 +0100
commit8b6a666a97544bf307190a05947742b8357aa962 (patch)
tree16c344dabab751936bd81e720cc58620013976be
parent23a289137ab82daeea826eeb9556c6f89b1fcd67 (diff)
downloadlinux-8b6a666a97544bf307190a05947742b8357aa962.tar.bz2
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: David Howells <dhowells@redhat.com>
-rw-r--r--fs/afs/internal.h1
-rw-r--r--fs/afs/security.c33
-rw-r--r--include/linux/key.h14
3 files changed, 45 insertions, 3 deletions
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index f66a3be12fd6..9cdfabaeaa0b 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -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);
diff --git a/fs/afs/security.c b/fs/afs/security.c
index 71e71c07568f..ef2fd34ba282 100644
--- a/fs/afs/security.c
+++ b/fs/afs/security.c
@@ -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));
diff --git a/include/linux/key.h b/include/linux/key.h
index 50028338a4cc..6cf8e71cf8b7 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -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);