[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, 399 insertions, 0 deletions

diff --git a/net/rxrpc/ar-accept.c b/net/rxrpc/ar-accept.c
new file mode 100644
index 0000000..e7af780
--- /dev/null
+++ b/net/rxrpc/ar-accept.c
@@ -0,0 +1,399 @@
+/* incoming call 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/errqueue.h>
+#include <linux/udp.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/icmp.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include <net/ip.h>
+#include "ar-internal.h"
+
+/*
+ * generate a connection-level abort
+ */
+static int rxrpc_busy(struct rxrpc_local *local, struct sockaddr_rxrpc *srx,
+		      struct rxrpc_header *hdr)
+{
+	struct msghdr msg;
+	struct kvec iov[1];
+	size_t len;
+	int ret;
+
+	_enter("%d,,", local->debug_id);
+
+	msg.msg_name	= &srx->transport.sin;
+	msg.msg_namelen	= sizeof(srx->transport.sin);
+	msg.msg_control	= NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags	= 0;
+
+	hdr->seq	= 0;
+	hdr->type	= RXRPC_PACKET_TYPE_BUSY;
+	hdr->flags	= 0;
+	hdr->userStatus	= 0;
+	hdr->_rsvd	= 0;
+
+	iov[0].iov_base	= hdr;
+	iov[0].iov_len	= sizeof(*hdr);
+
+	len = iov[0].iov_len;
+
+	hdr->serial = htonl(1);
+	_proto("Tx BUSY %%%u", ntohl(hdr->serial));
+
+	ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
+	if (ret < 0) {
+		_leave(" = -EAGAIN [sendmsg failed: %d]", ret);
+		return -EAGAIN;
+	}
+
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * accept an incoming call that needs peer, transport and/or connection setting
+ * up
+ */
+static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
+				      struct rxrpc_sock *rx,
+				      struct sk_buff *skb,
+				      struct sockaddr_rxrpc *srx)
+{
+	struct rxrpc_connection *conn;
+	struct rxrpc_transport *trans;
+	struct rxrpc_skb_priv *sp, *nsp;
+	struct rxrpc_peer *peer;
+	struct rxrpc_call *call;
+	struct sk_buff *notification;
+	int ret;
+
+	_enter("");
+
+	sp = rxrpc_skb(skb);
+
+	/* get a notification message to send to the server app */
+	notification = alloc_skb(0, GFP_NOFS);
+	rxrpc_new_skb(notification);
+	notification->mark = RXRPC_SKB_MARK_NEW_CALL;
+
+	peer = rxrpc_get_peer(srx, GFP_NOIO);
+	if (IS_ERR(peer)) {
+		_debug("no peer");
+		ret = -EBUSY;
+		goto error;
+	}
+
+	trans = rxrpc_get_transport(local, peer, GFP_NOIO);
+	rxrpc_put_peer(peer);
+	if (!trans) {
+		_debug("no trans");
+		ret = -EBUSY;
+		goto error;
+	}
+
+	conn = rxrpc_incoming_connection(trans, &sp->hdr, GFP_NOIO);
+	rxrpc_put_transport(trans);
+	if (IS_ERR(conn)) {
+		_debug("no conn");
+		ret = PTR_ERR(conn);
+		goto error;
+	}
+
+	call = rxrpc_incoming_call(rx, conn, &sp->hdr, GFP_NOIO);
+	rxrpc_put_connection(conn);
+	if (IS_ERR(call)) {
+		_debug("no call");
+		ret = PTR_ERR(call);
+		goto error;
+	}
+
+	/* attach the call to the socket */
+	read_lock_bh(&local->services_lock);
+	if (rx->sk.sk_state == RXRPC_CLOSE)
+		goto invalid_service;
+
+	write_lock(&rx->call_lock);
+	if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
+		rxrpc_get_call(call);
+
+		spin_lock(&call->conn->state_lock);
+		if (sp->hdr.securityIndex > 0 &&
+		    call->conn->state == RXRPC_CONN_SERVER_UNSECURED) {
+			_debug("await conn sec");
+			list_add_tail(&call->accept_link, &rx->secureq);
+			call->conn->state = RXRPC_CONN_SERVER_CHALLENGING;
+			atomic_inc(&call->conn->usage);
+			set_bit(RXRPC_CONN_CHALLENGE, &call->conn->events);
+			schedule_work(&call->conn->processor);
+		} else {
+			_debug("conn ready");
+			call->state = RXRPC_CALL_SERVER_ACCEPTING;
+			list_add_tail(&call->accept_link, &rx->acceptq);
+			rxrpc_get_call(call);
+			nsp = rxrpc_skb(notification);
+			nsp->call = call;
+
+			ASSERTCMP(atomic_read(&call->usage), >=, 3);
+
+			_debug("notify");
+			spin_lock(&call->lock);
+			ret = rxrpc_queue_rcv_skb(call, notification, true,
+						  false);
+			spin_unlock(&call->lock);
+			notification = NULL;
+			if (ret < 0)
+				BUG();
+		}
+		spin_unlock(&call->conn->state_lock);
+
+		_debug("queued");
+	}
+	write_unlock(&rx->call_lock);
+
+	_debug("process");
+	rxrpc_fast_process_packet(call, skb);
+
+	_debug("done");
+	read_unlock_bh(&local->services_lock);
+	rxrpc_free_skb(notification);
+	rxrpc_put_call(call);
+	_leave(" = 0");
+	return 0;
+
+invalid_service:
+	_debug("invalid");
+	read_unlock_bh(&local->services_lock);
+
+	read_lock_bh(&call->state_lock);
+	if (!test_bit(RXRPC_CALL_RELEASE, &call->flags) &&
+	    !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events)) {
+		rxrpc_get_call(call);
+		schedule_work(&call->processor);
+	}
+	read_unlock_bh(&call->state_lock);
+	rxrpc_put_call(call);
+	ret = -ECONNREFUSED;
+error:
+	rxrpc_free_skb(notification);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * accept incoming calls that need peer, transport and/or connection setting up
+ * - the packets we get are all incoming client DATA packets that have seq == 1
+ */
+void rxrpc_accept_incoming_calls(struct work_struct *work)
+{
+	struct rxrpc_local *local =
+		container_of(work, struct rxrpc_local, acceptor);
+	struct rxrpc_skb_priv *sp;
+	struct sockaddr_rxrpc srx;
+	struct rxrpc_sock *rx;
+	struct sk_buff *skb;
+	__be16 service_id;
+	int ret;
+
+	_enter("%d", local->debug_id);
+
+	read_lock_bh(&rxrpc_local_lock);
+	if (atomic_read(&local->usage) > 0)
+		rxrpc_get_local(local);
+	else
+		local = NULL;
+	read_unlock_bh(&rxrpc_local_lock);
+	if (!local) {
+		_leave(" [local dead]");
+		return;
+	}
+
+process_next_packet:
+	skb = skb_dequeue(&local->accept_queue);
+	if (!skb) {
+		rxrpc_put_local(local);
+		_leave("\n");
+		return;
+	}
+
+	_net("incoming call skb %p", skb);
+
+	sp = rxrpc_skb(skb);
+
+	/* determine the remote address */
+	memset(&srx, 0, sizeof(srx));
+	srx.srx_family = AF_RXRPC;
+	srx.transport.family = local->srx.transport.family;
+	srx.transport_type = local->srx.transport_type;
+	switch (srx.transport.family) {
+	case AF_INET:
+		srx.transport_len = sizeof(struct sockaddr_in);
+		srx.transport.sin.sin_port = udp_hdr(skb)->source;
+		srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
+		break;
+	default:
+		goto busy;
+	}
+
+	/* get the socket providing the service */
+	service_id = sp->hdr.serviceId;
+	read_lock_bh(&local->services_lock);
+	list_for_each_entry(rx, &local->services, listen_link) {
+		if (rx->service_id == service_id &&
+		    rx->sk.sk_state != RXRPC_CLOSE)
+			goto found_service;
+	}
+	read_unlock_bh(&local->services_lock);
+	goto invalid_service;
+
+found_service:
+	_debug("found service %hd", ntohs(rx->service_id));
+	if (sk_acceptq_is_full(&rx->sk))
+		goto backlog_full;
+	sk_acceptq_added(&rx->sk);
+	sock_hold(&rx->sk);
+	read_unlock_bh(&local->services_lock);
+
+	ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
+	if (ret < 0)
+		sk_acceptq_removed(&rx->sk);
+	sock_put(&rx->sk);
+	switch (ret) {
+	case -ECONNRESET: /* old calls are ignored */
+	case -ECONNABORTED: /* aborted calls are reaborted or ignored */
+	case 0:
+		goto process_next_packet;
+	case -ECONNREFUSED:
+		goto invalid_service;
+	case -EBUSY:
+		goto busy;
+	case -EKEYREJECTED:
+		goto security_mismatch;
+	default:
+		BUG();
+	}
+
+backlog_full:
+	read_unlock_bh(&local->services_lock);
+busy:
+	rxrpc_busy(local, &srx, &sp->hdr);
+	rxrpc_free_skb(skb);
+	goto process_next_packet;
+
+invalid_service:
+	skb->priority = RX_INVALID_OPERATION;
+	rxrpc_reject_packet(local, skb);
+	goto process_next_packet;
+
+	/* can't change connection security type mid-flow */
+security_mismatch:
+	skb->priority = RX_PROTOCOL_ERROR;
+	rxrpc_reject_packet(local, skb);
+	goto process_next_packet;
+}
+
+/*
+ * handle acceptance of a call by userspace
+ * - assign the user call ID to the call at the front of the queue
+ */
+int rxrpc_accept_call(struct rxrpc_sock *rx, unsigned long user_call_ID)
+{
+	struct rxrpc_call *call;
+	struct rb_node *parent, **pp;
+	int ret;
+
+	_enter(",%lx", user_call_ID);
+
+	ASSERT(!irqs_disabled());
+
+	write_lock(&rx->call_lock);
+
+	ret = -ENODATA;
+	if (list_empty(&rx->acceptq))
+		goto out;
+
+	/* check the user ID isn't already in use */
+	ret = -EBADSLT;
+	pp = &rx->calls.rb_node;
+	parent = NULL;
+	while (*pp) {
+		parent = *pp;
+		call = rb_entry(parent, struct rxrpc_call, sock_node);
+
+		if (user_call_ID < call->user_call_ID)
+			pp = &(*pp)->rb_left;
+		else if (user_call_ID > call->user_call_ID)
+			pp = &(*pp)->rb_right;
+		else
+			goto out;
+	}
+
+	/* dequeue the first call and check it's still valid */
+	call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
+	list_del_init(&call->accept_link);
+	sk_acceptq_removed(&rx->sk);
+
+	write_lock_bh(&call->state_lock);
+	switch (call->state) {
+	case RXRPC_CALL_SERVER_ACCEPTING:
+		call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
+		break;
+	case RXRPC_CALL_REMOTELY_ABORTED:
+	case RXRPC_CALL_LOCALLY_ABORTED:
+		ret = -ECONNABORTED;
+		goto out_release;
+	case RXRPC_CALL_NETWORK_ERROR:
+		ret = call->conn->error;
+		goto out_release;
+	case RXRPC_CALL_DEAD:
+		ret = -ETIME;
+		goto out_discard;
+	default:
+		BUG();
+	}
+
+	/* formalise the acceptance */
+	call->user_call_ID = user_call_ID;
+	rb_link_node(&call->sock_node, parent, pp);
+	rb_insert_color(&call->sock_node, &rx->calls);
+	if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
+		BUG();
+	if (test_and_set_bit(RXRPC_CALL_ACCEPTED, &call->events))
+		BUG();
+	schedule_work(&call->processor);
+
+	write_unlock_bh(&call->state_lock);
+	write_unlock(&rx->call_lock);
+	_leave(" = 0");
+	return 0;
+
+	/* if the call is already dying or dead, then we leave the socket's ref
+	 * on it to be released by rxrpc_dead_call_expired() as induced by
+	 * rxrpc_release_call() */
+out_release:
+	_debug("release %p", call);
+	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
+	    !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
+		schedule_work(&call->processor);
+out_discard:
+	write_unlock_bh(&call->state_lock);
+	_debug("discard %p", call);
+out:
+	write_unlock(&rx->call_lock);
+	_leave(" = %d", ret);
+	return ret;
+}