rxrpc: Fix missing security check on incoming calls

Fix rxrpc_new_incoming_call() to check that we have a suitable service key
available for the combination of service ID and security class of a new
incoming call - and to reject calls for which we don't.

This causes an assertion like the following to appear:

	rxrpc: Assertion failed - 6(0x6) == 12(0xc) is false
	kernel BUG at net/rxrpc/call_object.c:456!

Where call->state is RXRPC_CALL_SERVER_SECURING (6) rather than
RXRPC_CALL_COMPLETE (12).

Fixes: 248f219c ("rxrpc: Rewrite the data and ack handling code")
Reported-by: NMarc Dionne <marc.dionne@auristor.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

net/rxrpc/ar-internal.h

@@ -209,6 +209,7 @@ struct rxrpc_skb_priv {
 struct rxrpc_security {
 	const char		*name;		/* name of this service */
 	u8			security_index;	/* security type provided */
+	u32			no_key_abort;	/* Abort code indicating no key */
 
 	/* Initialise a security service */
 	int (*init)(void);
@@ -977,8 +978,9 @@ static inline void rxrpc_reduce_conn_timer(struct rxrpc_connection *conn,
 struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *,
 						     struct sk_buff *);
 struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *, gfp_t);
-void rxrpc_new_incoming_connection(struct rxrpc_sock *,
-				   struct rxrpc_connection *, struct sk_buff *);
+void rxrpc_new_incoming_connection(struct rxrpc_sock *, struct rxrpc_connection *,
+				   const struct rxrpc_security *, struct key *,
+				   struct sk_buff *);
 void rxrpc_unpublish_service_conn(struct rxrpc_connection *);
 
 /*
@@ -1103,7 +1105,9 @@ extern const struct rxrpc_security rxkad;
 int __init rxrpc_init_security(void);
 void rxrpc_exit_security(void);
 int rxrpc_init_client_conn_security(struct rxrpc_connection *);
-int rxrpc_init_server_conn_security(struct rxrpc_connection *);
+bool rxrpc_look_up_server_security(struct rxrpc_local *, struct rxrpc_sock *,
+				   const struct rxrpc_security **, struct key **,
+				   struct sk_buff *);
 
 /*
  * sendmsg.c

net/rxrpc/call_accept.c

@@ -263,6 +263,8 @@ static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
 						    struct rxrpc_local *local,
 						    struct rxrpc_peer *peer,
 						    struct rxrpc_connection *conn,
+						    const struct rxrpc_security *sec,
+						    struct key *key,
 						    struct sk_buff *skb)
 {
 	struct rxrpc_backlog *b = rx->backlog;
@@ -310,7 +312,7 @@ static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
 		conn->params.local = rxrpc_get_local(local);
 		conn->params.peer = peer;
 		rxrpc_see_connection(conn);
-		rxrpc_new_incoming_connection(rx, conn, skb);
+		rxrpc_new_incoming_connection(rx, conn, sec, key, skb);
 	} else {
 		rxrpc_get_connection(conn);
 	}
@@ -349,9 +351,11 @@ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
 					   struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	const struct rxrpc_security *sec = NULL;
 	struct rxrpc_connection *conn;
 	struct rxrpc_peer *peer = NULL;
-	struct rxrpc_call *call;
+	struct rxrpc_call *call = NULL;
+	struct key *key = NULL;
 
 	_enter("");
 
@@ -372,7 +376,11 @@ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
 	 */
 	conn = rxrpc_find_connection_rcu(local, skb, &peer);
 
-	call = rxrpc_alloc_incoming_call(rx, local, peer, conn, skb);
+	if (!conn && !rxrpc_look_up_server_security(local, rx, &sec, &key, skb))
+		goto no_call;
+
+	call = rxrpc_alloc_incoming_call(rx, local, peer, conn, sec, key, skb);
+	key_put(key);
 	if (!call) {
 		skb->mark = RXRPC_SKB_MARK_REJECT_BUSY;
 		goto no_call;

net/rxrpc/conn_event.c

@@ -376,21 +376,7 @@ static void rxrpc_secure_connection(struct rxrpc_connection *conn)
 	_enter("{%d}", conn->debug_id);
 
 	ASSERT(conn->security_ix != 0);
-
-	if (!conn->params.key) {
-		_debug("set up security");
-		ret = rxrpc_init_server_conn_security(conn);
-		switch (ret) {
-		case 0:
-			break;
-		case -ENOENT:
-			abort_code = RX_CALL_DEAD;
-			goto abort;
-		default:
-			abort_code = RXKADNOAUTH;
-			goto abort;
-		}
-	}
+	ASSERT(conn->server_key);
 
 	if (conn->security->issue_challenge(conn) < 0) {
 		abort_code = RX_CALL_DEAD;

net/rxrpc/conn_service.c

@@ -148,6 +148,8 @@ struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *rxn
  */
 void rxrpc_new_incoming_connection(struct rxrpc_sock *rx,
 				   struct rxrpc_connection *conn,
+				   const struct rxrpc_security *sec,
+				   struct key *key,
 				   struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
@@ -160,6 +162,8 @@ void rxrpc_new_incoming_connection(struct rxrpc_sock *rx,
 	conn->service_id	= sp->hdr.serviceId;
 	conn->security_ix	= sp->hdr.securityIndex;
 	conn->out_clientflag	= 0;
+	conn->security		= sec;
+	conn->server_key	= key_get(key);
 	if (conn->security_ix)
 		conn->state	= RXRPC_CONN_SERVICE_UNSECURED;
 	else

net/rxrpc/rxkad.c

@@ -648,9 +648,9 @@ static int rxkad_issue_challenge(struct rxrpc_connection *conn)
 	u32 serial;
 	int ret;
 
-	_enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
+	_enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
 
-	ret = key_validate(conn->params.key);
+	ret = key_validate(conn->server_key);
 	if (ret < 0)
 		return ret;
 
@@ -1293,6 +1293,7 @@ static void rxkad_exit(void)
 const struct rxrpc_security rxkad = {
 	.name				= "rxkad",
 	.security_index			= RXRPC_SECURITY_RXKAD,
+	.no_key_abort			= RXKADUNKNOWNKEY,
 	.init				= rxkad_init,
 	.exit				= rxkad_exit,
 	.init_connection_security	= rxkad_init_connection_security,

net/rxrpc/security.c

@@ -101,62 +101,58 @@ int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
 }
 
 /*
- * initialise the security on a server connection
+ * Find the security key for a server connection.
  */
-int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
+bool rxrpc_look_up_server_security(struct rxrpc_local *local, struct rxrpc_sock *rx,
+				   const struct rxrpc_security **_sec,
+				   struct key **_key,
+				   struct sk_buff *skb)
 {
 	const struct rxrpc_security *sec;
-	struct rxrpc_local *local = conn->params.local;
-	struct rxrpc_sock *rx;
-	struct key *key;
-	key_ref_t kref;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	key_ref_t kref = NULL;
 	char kdesc[5 + 1 + 3 + 1];
 
 	_enter("");
 
-	sprintf(kdesc, "%u:%u", conn->service_id, conn->security_ix);
+	sprintf(kdesc, "%u:%u", sp->hdr.serviceId, sp->hdr.securityIndex);
 
-	sec = rxrpc_security_lookup(conn->security_ix);
+	sec = rxrpc_security_lookup(sp->hdr.securityIndex);
 	if (!sec) {
-		_leave(" = -ENOKEY [lookup]");
-		return -ENOKEY;
+		trace_rxrpc_abort(0, "SVS",
+				  sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+				  RX_INVALID_OPERATION, EKEYREJECTED);
+		skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
+		skb->priority = RX_INVALID_OPERATION;
+		return false;
 	}
 
-	/* find the service */
-	read_lock(&local->services_lock);
-	rx = rcu_dereference_protected(local->service,
-				       lockdep_is_held(&local->services_lock));
-	if (rx && (rx->srx.srx_service == conn->service_id ||
-		   rx->second_service == conn->service_id))
-		goto found_service;
+	if (sp->hdr.securityIndex == RXRPC_SECURITY_NONE)
+		goto out;
 
-	/* the service appears to have died */
-	read_unlock(&local->services_lock);
-	_leave(" = -ENOENT");
-	return -ENOENT;
-
-found_service:
 	if (!rx->securities) {
-		read_unlock(&local->services_lock);
-		_leave(" = -ENOKEY");
-		return -ENOKEY;
+		trace_rxrpc_abort(0, "SVR",
+				  sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+				  RX_INVALID_OPERATION, EKEYREJECTED);
+		skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
+		skb->priority = RX_INVALID_OPERATION;
+		return false;
 	}
 
 	/* look through the service's keyring */
 	kref = keyring_search(make_key_ref(rx->securities, 1UL),
 			      &key_type_rxrpc_s, kdesc, true);
 	if (IS_ERR(kref)) {
-		read_unlock(&local->services_lock);
-		_leave(" = %ld [search]", PTR_ERR(kref));
-		return PTR_ERR(kref);
+		trace_rxrpc_abort(0, "SVK",
+				  sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+				  sec->no_key_abort, EKEYREJECTED);
+		skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
+		skb->priority = sec->no_key_abort;
+		return false;
 	}
 
-	key = key_ref_to_ptr(kref);
-	read_unlock(&local->services_lock);
-
-	conn->server_key = key;
-	conn->security = sec;
-
-	_leave(" = 0");
-	return 0;
+out:
+	*_sec = sec;
+	*_key = key_ref_to_ptr(kref);
+	return true;
 }