[PATCH] keys: discard the contents of a key on revocation
Cause the keys linked to a keyring to be unlinked from it when revoked and it
causes the data attached to a user-defined key to be discarded when revoked.
This frees up most of the quota a key occupied at that point, rather than
waiting for the key to actually be destroyed.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/keys/user-type.h b/include/keys/user-type.h
index a3dae18..c37c342 100644
--- a/include/keys/user-type.h
+++ b/include/keys/user-type.h
@@ -37,6 +37,7 @@
extern int user_instantiate(struct key *key, const void *data, size_t datalen);
extern int user_update(struct key *key, const void *data, size_t datalen);
extern int user_match(const struct key *key, const void *criterion);
+extern void user_revoke(struct key *key);
extern void user_destroy(struct key *key);
extern void user_describe(const struct key *user, struct seq_file *m);
extern long user_read(const struct key *key,
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 6c282bd..e8d02ac 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -49,6 +49,7 @@
static int keyring_instantiate(struct key *keyring,
const void *data, size_t datalen);
static int keyring_match(const struct key *keyring, const void *criterion);
+static void keyring_revoke(struct key *keyring);
static void keyring_destroy(struct key *keyring);
static void keyring_describe(const struct key *keyring, struct seq_file *m);
static long keyring_read(const struct key *keyring,
@@ -59,6 +60,7 @@
.def_datalen = sizeof(struct keyring_list),
.instantiate = keyring_instantiate,
.match = keyring_match,
+ .revoke = keyring_revoke,
.destroy = keyring_destroy,
.describe = keyring_describe,
.read = keyring_read,
@@ -953,3 +955,22 @@
} /* end keyring_clear() */
EXPORT_SYMBOL(keyring_clear);
+
+/*****************************************************************************/
+/*
+ * dispose of the links from a revoked keyring
+ * - called with the key sem write-locked
+ */
+static void keyring_revoke(struct key *keyring)
+{
+ struct keyring_list *klist = keyring->payload.subscriptions;
+
+ /* adjust the quota */
+ key_payload_reserve(keyring, 0);
+
+ if (klist) {
+ rcu_assign_pointer(keyring->payload.subscriptions, NULL);
+ call_rcu(&klist->rcu, keyring_clear_rcu_disposal);
+ }
+
+} /* end keyring_revoke() */
diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 8e71895..5bbfdeb 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -28,6 +28,7 @@
.instantiate = user_instantiate,
.update = user_update,
.match = user_match,
+ .revoke = user_revoke,
.destroy = user_destroy,
.describe = user_describe,
.read = user_read,
@@ -67,6 +68,7 @@
return ret;
} /* end user_instantiate() */
+
EXPORT_SYMBOL_GPL(user_instantiate);
/*****************************************************************************/
@@ -141,7 +143,28 @@
/*****************************************************************************/
/*
- * dispose of the data dangling from the corpse of a user
+ * dispose of the links from a revoked keyring
+ * - called with the key sem write-locked
+ */
+void user_revoke(struct key *key)
+{
+ struct user_key_payload *upayload = key->payload.data;
+
+ /* clear the quota */
+ key_payload_reserve(key, 0);
+
+ if (upayload) {
+ rcu_assign_pointer(key->payload.data, NULL);
+ call_rcu(&upayload->rcu, user_update_rcu_disposal);
+ }
+
+} /* end user_revoke() */
+
+EXPORT_SYMBOL(user_revoke);
+
+/*****************************************************************************/
+/*
+ * dispose of the data dangling from the corpse of a user key
*/
void user_destroy(struct key *key)
{