[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both

Provide AF_RXRPC sockets that can be used to talk to AFS servers, or serve
answers to AFS clients.  KerberosIV security is fully supported.  The patches
and some example test programs can be found in:

	http://people.redhat.com/~dhowells/rxrpc/

This will eventually replace the old implementation of kernel-only RxRPC
currently resident in net/rxrpc/.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 258 insertions, 0 deletions

diff --git a/net/rxrpc/ar-security.c b/net/rxrpc/ar-security.c
new file mode 100644
index 00000000000..60d1d364430
--- /dev/null
+++ b/net/rxrpc/ar-security.c
@@ -0,0 +1,258 @@
+/* RxRPC security handling
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/udp.h>
+#include <linux/crypto.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+static LIST_HEAD(rxrpc_security_methods);
+static DECLARE_RWSEM(rxrpc_security_sem);
+
+/*
+ * get an RxRPC security module
+ */
+static struct rxrpc_security *rxrpc_security_get(struct rxrpc_security *sec)
+{
+	return try_module_get(sec->owner) ? sec : NULL;
+}
+
+/*
+ * release an RxRPC security module
+ */
+static void rxrpc_security_put(struct rxrpc_security *sec)
+{
+	module_put(sec->owner);
+}
+
+/*
+ * look up an rxrpc security module
+ */
+struct rxrpc_security *rxrpc_security_lookup(u8 security_index)
+{
+	struct rxrpc_security *sec = NULL;
+
+	_enter("");
+
+	down_read(&rxrpc_security_sem);
+
+	list_for_each_entry(sec, &rxrpc_security_methods, link) {
+		if (sec->security_index == security_index) {
+			if (unlikely(!rxrpc_security_get(sec)))
+				break;
+			goto out;
+		}
+	}
+
+	sec = NULL;
+out:
+	up_read(&rxrpc_security_sem);
+	_leave(" = %p [%s]", sec, sec ? sec->name : "");
+	return sec;
+}
+
+/**
+ * rxrpc_register_security - register an RxRPC security handler
+ * @sec: security module
+ *
+ * register an RxRPC security handler for use by RxRPC
+ */
+int rxrpc_register_security(struct rxrpc_security *sec)
+{
+	struct rxrpc_security *psec;
+	int ret;
+
+	_enter("");
+	down_write(&rxrpc_security_sem);
+
+	ret = -EEXIST;
+	list_for_each_entry(psec, &rxrpc_security_methods, link) {
+		if (psec->security_index == sec->security_index)
+			goto out;
+	}
+
+	list_add(&sec->link, &rxrpc_security_methods);
+
+	printk(KERN_NOTICE "RxRPC: Registered security type %d '%s'\n",
+	       sec->security_index, sec->name);
+	ret = 0;
+
+out:
+	up_write(&rxrpc_security_sem);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+EXPORT_SYMBOL_GPL(rxrpc_register_security);
+
+/**
+ * rxrpc_unregister_security - unregister an RxRPC security handler
+ * @sec: security module
+ *
+ * unregister an RxRPC security handler
+ */
+void rxrpc_unregister_security(struct rxrpc_security *sec)
+{
+
+	_enter("");
+	down_write(&rxrpc_security_sem);
+	list_del_init(&sec->link);
+	up_write(&rxrpc_security_sem);
+
+	printk(KERN_NOTICE "RxRPC: Unregistered security type %d '%s'\n",
+	       sec->security_index, sec->name);
+}
+
+EXPORT_SYMBOL_GPL(rxrpc_unregister_security);
+
+/*
+ * initialise the security on a client connection
+ */
+int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
+{
+	struct rxrpc_security *sec;
+	struct key *key = conn->key;
+	int ret;
+
+	_enter("{%d},{%x}", conn->debug_id, key_serial(key));
+
+	if (!key)
+		return 0;
+
+	ret = key_validate(key);
+	if (ret < 0)
+		return ret;
+
+	sec = rxrpc_security_lookup(key->type_data.x[0]);
+	if (!sec)
+		return -EKEYREJECTED;
+	conn->security = sec;
+
+	ret = conn->security->init_connection_security(conn);
+	if (ret < 0) {
+		rxrpc_security_put(conn->security);
+		conn->security = NULL;
+		return ret;
+	}
+
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * initialise the security on a server connection
+ */
+int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
+{
+	struct rxrpc_security *sec;
+	struct rxrpc_local *local = conn->trans->local;
+	struct rxrpc_sock *rx;
+	struct key *key;
+	key_ref_t kref;
+	char kdesc[5+1+3+1];
+
+	_enter("");
+
+	sprintf(kdesc, "%u:%u", ntohs(conn->service_id), conn->security_ix);
+
+	sec = rxrpc_security_lookup(conn->security_ix);
+	if (!sec) {
+		_leave(" = -ENOKEY [lookup]");
+		return -ENOKEY;
+	}
+
+	/* find the service */
+	read_lock_bh(&local->services_lock);
+	list_for_each_entry(rx, &local->services, listen_link) {
+		if (rx->service_id == conn->service_id)
+			goto found_service;
+	}
+
+	/* the service appears to have died */
+	read_unlock_bh(&local->services_lock);
+	rxrpc_security_put(sec);
+	_leave(" = -ENOENT");
+	return -ENOENT;
+
+found_service:
+	if (!rx->securities) {
+		read_unlock_bh(&local->services_lock);
+		rxrpc_security_put(sec);
+		_leave(" = -ENOKEY");
+		return -ENOKEY;
+	}
+
+	/* look through the service's keyring */
+	kref = keyring_search(make_key_ref(rx->securities, 1UL),
+			      &key_type_rxrpc_s, kdesc);
+	if (IS_ERR(kref)) {
+		read_unlock_bh(&local->services_lock);
+		rxrpc_security_put(sec);
+		_leave(" = %ld [search]", PTR_ERR(kref));
+		return PTR_ERR(kref);
+	}
+
+	key = key_ref_to_ptr(kref);
+	read_unlock_bh(&local->services_lock);
+
+	conn->server_key = key;
+	conn->security = sec;
+
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * secure a packet prior to transmission
+ */
+int rxrpc_secure_packet(const struct rxrpc_call *call,
+			struct sk_buff *skb,
+			size_t data_size,
+			void *sechdr)
+{
+	if (call->conn->security)
+		return call->conn->security->secure_packet(
+			call, skb, data_size, sechdr);
+	return 0;
+}
+
+/*
+ * secure a packet prior to transmission
+ */
+int rxrpc_verify_packet(const struct rxrpc_call *call, struct sk_buff *skb,
+			u32 *_abort_code)
+{
+	if (call->conn->security)
+		return call->conn->security->verify_packet(
+			call, skb, _abort_code);
+	return 0;
+}
+
+/*
+ * clear connection security
+ */
+void rxrpc_clear_conn_security(struct rxrpc_connection *conn)
+{
+	_enter("{%d}", conn->debug_id);
+
+	if (conn->security) {
+		conn->security->clear(conn);
+		rxrpc_security_put(conn->security);
+		conn->security = NULL;
+	}
+
+	key_put(conn->key);
+	key_put(conn->server_key);
+}