1 files changed, 44 insertions, 1 deletions

diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index 0ecc2e8d2bd0..cb9817ced3fd 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -20,6 +20,7 @@
 
 static int request_key_auth_instantiate(struct key *, const void *, size_t);
 static void request_key_auth_describe(const struct key *, struct seq_file *);
+static void request_key_auth_revoke(struct key *);
 static void request_key_auth_destroy(struct key *);
 static long request_key_auth_read(const struct key *, char __user *, size_t);
 
@@ -31,6 +32,7 @@ struct key_type key_type_request_key_auth = {
 	.def_datalen	= sizeof(struct request_key_auth),
 	.instantiate	= request_key_auth_instantiate,
 	.describe	= request_key_auth_describe,
+	.revoke		= request_key_auth_revoke,
 	.destroy	= request_key_auth_destroy,
 	.read		= request_key_auth_read,
 };
@@ -93,6 +95,24 @@ static long request_key_auth_read(const struct key *key,
 
 /*****************************************************************************/
 /*
+ * handle revocation of an authorisation token key
+ * - called with the key sem write-locked
+ */
+static void request_key_auth_revoke(struct key *key)
+{
+	struct request_key_auth *rka = key->payload.data;
+
+	kenter("{%d}", key->serial);
+
+	if (rka->context) {
+		put_task_struct(rka->context);
+		rka->context = NULL;
+	}
+
+} /* end request_key_auth_revoke() */
+
+/*****************************************************************************/
+/*
  * destroy an instantiation authorisation token key
  */
 static void request_key_auth_destroy(struct key *key)
@@ -101,6 +121,11 @@ static void request_key_auth_destroy(struct key *key)
 
 	kenter("{%d}", key->serial);
 
+	if (rka->context) {
+		put_task_struct(rka->context);
+		rka->context = NULL;
+	}
+
 	key_put(rka->target_key);
 	kfree(rka);
 
@@ -131,14 +156,26 @@ struct key *request_key_auth_new(struct key *target, const char *callout_info)
 	 * another process */
 	if (current->request_key_auth) {
 		/* it is - use that instantiation context here too */
+		down_read(&current->request_key_auth->sem);
+
+		/* if the auth key has been revoked, then the key we're
+		 * servicing is already instantiated */
+		if (test_bit(KEY_FLAG_REVOKED,
+			     &current->request_key_auth->flags))
+			goto auth_key_revoked;
+
 		irka = current->request_key_auth->payload.data;
 		rka->context = irka->context;
 		rka->pid = irka->pid;
+		get_task_struct(rka->context);
+
+		up_read(&current->request_key_auth->sem);
 	}
 	else {
 		/* it isn't - use this process as the context */
 		rka->context = current;
 		rka->pid = current->pid;
+		get_task_struct(rka->context);
 	}
 
 	rka->target_key = key_get(target);
@@ -161,9 +198,15 @@ struct key *request_key_auth_new(struct key *target, const char *callout_info)
 	if (ret < 0)
 		goto error_inst;
 
-	kleave(" = {%d})", authkey->serial);
+	kleave(" = {%d}", authkey->serial);
 	return authkey;
 
+auth_key_revoked:
+	up_read(&current->request_key_auth->sem);
+	kfree(rka);
+	kleave("= -EKEYREVOKED");
+	return ERR_PTR(-EKEYREVOKED);
+
 error_inst:
 	key_revoke(authkey);
 	key_put(authkey);