Merge branch 'rxrpc-miscellaneous-fixes'

David Howells says:

====================
rxrpc: Miscellaneous fixes

Here are some miscellaneous AF_RXRPC fixes:

 (1) Make sure rxrpc_verify_data() allocates a buffer, even if the DATA
     packet being looked at is zero length to avoid potential NULL-pointer
     exceptions.

 (2) Don't move an OOB message (e.g. an RxGK CHALLENGE) off the receive
     queue onto the pending queue in recvmsg() if MSG_PEEK is specified.

 (3) Fix a potential UAF in rxgk_issue_challenge() in which a tracepoint
     refers to memory just freed by a different pointer.

 (4) Fix afs net namespace teardown to cancel the incoming call
     preallocation charger before we disable listening (which will delete
     the preallocation queue).

 (5) Fix rxrpc_kernel_charge_accept() to use the socket mutex to defend
     against listen(0)/shutdown simultaneously deleting the preallocation
     queue.
====================

Link: https://patch.msgid.link/20260609140911.838677-1-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

fs/afs/rxrpc.c

@@ -127,6 +127,7 @@ void afs_close_socket(struct afs_net *net)
 {
 	_enter("");
 
+	cancel_work_sync(&net->charge_preallocation_work);
 	kernel_listen(net->socket, 0);
 	flush_workqueue(afs_async_calls);
 
@@ -742,7 +743,7 @@ void afs_charge_preallocation(struct work_struct *work)
 		container_of(work, struct afs_net, charge_preallocation_work);
 	struct afs_call *call = net->spare_incoming_call;
 
-	for (;;) {
+	while (READ_ONCE(net->live)) {
 		if (!call) {
 			call = afs_alloc_call(net, &afs_RXCMxxxx, GFP_KERNEL);
 			if (!call)
@@ -792,7 +793,8 @@ static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
 	if (!call->server)
 		trace_afs_cm_no_server(call, rxrpc_kernel_remote_srx(call->peer));
 
-	queue_work(afs_wq, &net->charge_preallocation_work);
+	if (net->live)
+		queue_work(afs_wq, &net->charge_preallocation_work);
 }
 
 /*

net/rxrpc/call_accept.c

@@ -471,13 +471,26 @@ int rxrpc_kernel_charge_accept(struct socket *sock, rxrpc_notify_rx_t notify_rx,
 			       unsigned long user_call_ID, gfp_t gfp,
 			       unsigned int debug_id)
 {
-	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
-	struct rxrpc_backlog *b = rx->backlog;
+	struct rxrpc_backlog *b;
+	struct rxrpc_sock *rx;
+	struct sock *sk;
+	int ret;
 
-	if (sock->sk->sk_state == RXRPC_CLOSE)
-		return -ESHUTDOWN;
+	sk = sock->sk;
+	rx = rxrpc_sk(sk);
 
-	return rxrpc_service_prealloc_one(rx, b, notify_rx, user_call_ID,
-					  gfp, debug_id);
+	lock_sock(sk);
+	if (sk->sk_state != RXRPC_SERVER_LISTENING || !rx->backlog) {
+		ret = -ESHUTDOWN;
+		goto out;
+	}
+
+	b = rx->backlog;
+	ret = rxrpc_service_prealloc_one(rx, b, notify_rx, user_call_ID,
+					 gfp, debug_id);
+
+out:
+	release_sock(sk);
+	return ret;
 }
 EXPORT_SYMBOL(rxrpc_kernel_charge_accept);

net/rxrpc/recvmsg.c

@@ -161,7 +161,7 @@ static int rxrpc_verify_data(struct rxrpc_call *call, struct sk_buff *skb)
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	int ret;
 
-	if (sp->len > call->rx_dec_bsize) {
+	if (sp->len > call->rx_dec_bsize || !call->rx_dec_buffer) {
 		/* Make sure we can hold a 1412-byte jumbo subpacket and make
 		 * sure that the buffer size is aligned to a crypto blocksize.
 		 */
@@ -262,12 +262,13 @@ static int rxrpc_recvmsg_oob(struct socket *sock, struct msghdr *msg,
 		break;
 	}
 
-	if (!(flags & MSG_PEEK))
+	if (!(flags & MSG_PEEK)) {
 		skb_unlink(skb, &rx->recvmsg_oobq);
-	if (need_response)
-		rxrpc_add_pending_oob(rx, skb);
-	else
-		rxrpc_free_skb(skb, rxrpc_skb_put_oob);
+		if (need_response)
+			rxrpc_add_pending_oob(rx, skb);
+		else
+			rxrpc_free_skb(skb, rxrpc_skb_put_oob);
+	}
 	return ret;
 }
 

net/rxrpc/rxgk.c

@@ -687,16 +687,17 @@ static int rxgk_issue_challenge(struct rxrpc_connection *conn)
 	ret = do_udp_sendmsg(conn->local->socket, &msg, len);
 	if (ret > 0)
 		rxrpc_peer_mark_tx(conn->peer);
-	__free_page(page);
 
 	if (ret < 0) {
 		trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
 				    rxrpc_tx_point_rxgk_challenge);
+		__free_page(page);
 		return -EAGAIN;
 	}
 
 	trace_rxrpc_tx_packet(conn->debug_id, whdr,
 			      rxrpc_tx_point_rxgk_challenge);
+	__free_page(page);
 	_leave(" = 0");
 	return 0;
 }