Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 194 insertions, 0 deletions

diff --git a/net/rxrpc/conn_service.c b/net/rxrpc/conn_service.c
new file mode 100644
index 0000000000..89ac05a711
--- /dev/null
+++ b/net/rxrpc/conn_service.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Service connection management
+ *
+ * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/slab.h>
+#include "ar-internal.h"
+
+/*
+ * Find a service connection under RCU conditions.
+ *
+ * We could use a hash table, but that is subject to bucket stuffing by an
+ * attacker as the client gets to pick the epoch and cid values and would know
+ * the hash function.  So, instead, we use a hash table for the peer and from
+ * that an rbtree to find the service connection.  Under ordinary circumstances
+ * it might be slower than a large hash table, but it is at least limited in
+ * depth.
+ */
+struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *peer,
+						     struct sk_buff *skb)
+{
+	struct rxrpc_connection *conn = NULL;
+	struct rxrpc_conn_proto k;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	struct rb_node *p;
+	unsigned int seq = 0;
+
+	k.epoch	= sp->hdr.epoch;
+	k.cid	= sp->hdr.cid & RXRPC_CIDMASK;
+
+	do {
+		/* Unfortunately, rbtree walking doesn't give reliable results
+		 * under just the RCU read lock, so we have to check for
+		 * changes.
+		 */
+		read_seqbegin_or_lock(&peer->service_conn_lock, &seq);
+
+		p = rcu_dereference_raw(peer->service_conns.rb_node);
+		while (p) {
+			conn = rb_entry(p, struct rxrpc_connection, service_node);
+
+			if (conn->proto.index_key < k.index_key)
+				p = rcu_dereference_raw(p->rb_left);
+			else if (conn->proto.index_key > k.index_key)
+				p = rcu_dereference_raw(p->rb_right);
+			else
+				break;
+			conn = NULL;
+		}
+	} while (need_seqretry(&peer->service_conn_lock, seq));
+
+	done_seqretry(&peer->service_conn_lock, seq);
+	_leave(" = %d", conn ? conn->debug_id : -1);
+	return conn;
+}
+
+/*
+ * Insert a service connection into a peer's tree, thereby making it a target
+ * for incoming packets.
+ */
+static void rxrpc_publish_service_conn(struct rxrpc_peer *peer,
+				       struct rxrpc_connection *conn)
+{
+	struct rxrpc_connection *cursor = NULL;
+	struct rxrpc_conn_proto k = conn->proto;
+	struct rb_node **pp, *parent;
+
+	write_seqlock(&peer->service_conn_lock);
+
+	pp = &peer->service_conns.rb_node;
+	parent = NULL;
+	while (*pp) {
+		parent = *pp;
+		cursor = rb_entry(parent,
+				  struct rxrpc_connection, service_node);
+
+		if (cursor->proto.index_key < k.index_key)
+			pp = &(*pp)->rb_left;
+		else if (cursor->proto.index_key > k.index_key)
+			pp = &(*pp)->rb_right;
+		else
+			goto found_extant_conn;
+	}
+
+	rb_link_node_rcu(&conn->service_node, parent, pp);
+	rb_insert_color(&conn->service_node, &peer->service_conns);
+conn_published:
+	set_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags);
+	write_sequnlock(&peer->service_conn_lock);
+	_leave(" = %d [new]", conn->debug_id);
+	return;
+
+found_extant_conn:
+	if (refcount_read(&cursor->ref) == 0)
+		goto replace_old_connection;
+	write_sequnlock(&peer->service_conn_lock);
+	/* We should not be able to get here.  rxrpc_incoming_connection() is
+	 * called in a non-reentrant context, so there can't be a race to
+	 * insert a new connection.
+	 */
+	BUG();
+
+replace_old_connection:
+	/* The old connection is from an outdated epoch. */
+	_debug("replace conn");
+	rb_replace_node_rcu(&cursor->service_node,
+			    &conn->service_node,
+			    &peer->service_conns);
+	clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &cursor->flags);
+	goto conn_published;
+}
+
+/*
+ * Preallocate a service connection.  The connection is placed on the proc and
+ * reap lists so that we don't have to get the lock from BH context.
+ */
+struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *rxnet,
+							   gfp_t gfp)
+{
+	struct rxrpc_connection *conn = rxrpc_alloc_connection(rxnet, gfp);
+
+	if (conn) {
+		/* We maintain an extra ref on the connection whilst it is on
+		 * the rxrpc_connections list.
+		 */
+		conn->state = RXRPC_CONN_SERVICE_PREALLOC;
+		refcount_set(&conn->ref, 2);
+
+		atomic_inc(&rxnet->nr_conns);
+		write_lock(&rxnet->conn_lock);
+		list_add_tail(&conn->link, &rxnet->service_conns);
+		list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
+		write_unlock(&rxnet->conn_lock);
+
+		rxrpc_see_connection(conn, rxrpc_conn_new_service);
+	}
+
+	return conn;
+}
+
+/*
+ * Set up an incoming connection.  This is called in BH context with the RCU
+ * read lock held.
+ */
+void rxrpc_new_incoming_connection(struct rxrpc_sock *rx,
+				   struct rxrpc_connection *conn,
+				   const struct rxrpc_security *sec,
+				   struct sk_buff *skb)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+
+	_enter("");
+
+	conn->proto.epoch	= sp->hdr.epoch;
+	conn->proto.cid		= sp->hdr.cid & RXRPC_CIDMASK;
+	conn->orig_service_id	= sp->hdr.serviceId;
+	conn->service_id	= sp->hdr.serviceId;
+	conn->security_ix	= sp->hdr.securityIndex;
+	conn->out_clientflag	= 0;
+	conn->security		= sec;
+	if (conn->security_ix)
+		conn->state	= RXRPC_CONN_SERVICE_UNSECURED;
+	else
+		conn->state	= RXRPC_CONN_SERVICE;
+
+	/* See if we should upgrade the service.  This can only happen on the
+	 * first packet on a new connection.  Once done, it applies to all
+	 * subsequent calls on that connection.
+	 */
+	if (sp->hdr.userStatus == RXRPC_USERSTATUS_SERVICE_UPGRADE &&
+	    conn->service_id == rx->service_upgrade.from)
+		conn->service_id = rx->service_upgrade.to;
+
+	atomic_set(&conn->active, 1);
+
+	/* Make the connection a target for incoming packets. */
+	rxrpc_publish_service_conn(conn->peer, conn);
+}
+
+/*
+ * Remove the service connection from the peer's tree, thereby removing it as a
+ * target for incoming packets.
+ */
+void rxrpc_unpublish_service_conn(struct rxrpc_connection *conn)
+{
+	struct rxrpc_peer *peer = conn->peer;
+
+	write_seqlock(&peer->service_conn_lock);
+	if (test_and_clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags))
+		rb_erase(&conn->service_node, &peer->service_conns);
+	write_sequnlock(&peer->service_conn_lock);
+}