From 18ae2a800516f79c05d495fc91afca8a46041dab Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Thu, 14 Apr 2022 14:22:21 +0200
Subject: [PATCH] SUNRPC: Ensure we flush any closed sockets before
 xs_xprt_free()

 We must ensure that all sockets are closed before we call
 xprt_free() and release the reference to the net namespace. The problem is
 that calling fput() will defer closing the socket until delayed_fput() gets
 called. Let's fix the situation by allowing rpciod and the transport teardown
 code (which runs on the system wq) to call __fput_sync(), and directly close
 the socket.
Git-commit: f00432063db1a0db484e85193eccc6845435b80e
Patch-mainline: v5.18-rc2
References: bsc#1198330 CVE-2022-28893

Reported-by: Felix Fu <foyjog@gmail.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: a73881c96d73 ("SUNRPC: Fix an Oops in udp_poll()")
Cc: stable@vger.kernel.org # 5.1.x: 3be232f11a3c: SUNRPC: Prevent immediate close+reconnect
Cc: stable@vger.kernel.org # 5.1.x: 89f42494f92f: SUNRPC: Don't call connect() more than once on a TCP socket
Cc: stable@vger.kernel.org # 5.1.x
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Vasant Karasulli <vkarasulli@suse.de>

---
 fs/file_table.c       |    1 +
 net/sunrpc/xprt.c     |    5 +----
 net/sunrpc/xprtsock.c |   16 +++++++++++++---
 3 files changed, 15 insertions(+), 7 deletions(-)

--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -375,6 +375,7 @@ void __fput_sync(struct file *file)
 }

 EXPORT_SYMBOL(fput);
+EXPORT_SYMBOL(__fput_sync);
 
 void __init files_init(void)
 {
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -877,10 +877,7 @@ void xprt_connect(struct rpc_task *task)
 	if (!xprt_lock_write(xprt, task))
 		return;

-	if (test_and_clear_bit(XPRT_CLOSE_WAIT, &xprt->state))
-		xprt->ops->close(xprt);
-
-	if (!xprt_connected(xprt)) {
+	if (!xprt_connected(xprt) && !test_bit(XPRT_CLOSE_WAIT, &xprt->state)) {
 		task->tk_rqstp->rq_connect_cookie = xprt->connect_cookie;
 		rpc_sleep_on_timeout(&xprt->pending, task, NULL,
 				xprt_request_timeout(task->tk_rqstp));
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -965,7 +965,7 @@ static int xs_local_send_request(struct
 
 	/* Close the stream if the previous transmission was incomplete */
 	if (xs_send_request_was_aborted(transport, req)) {
-		xs_close(xprt);
+		xprt_force_disconnect(xprt);
 		return -ENOTCONN;
 	}
 
@@ -1003,7 +1003,7 @@ static int xs_local_send_request(struct
 			-status);
 		/* fall through */
 	case -EPIPE:
-		xs_close(xprt);
+		xprt_force_disconnect(xprt);
 		status = -ENOTCONN;
 	}
 
@@ -1279,6 +1279,16 @@ static void xs_reset_transport(struct so
 
 	if (sk == NULL)
 		return;
+	/*
+	 * Make sure we're calling this in a context from which it is safe
+	 * to call __fput_sync(). In practice that means rpciod and the
+	 * system workqueue.
+	 */
+	if (!(current->flags & PF_WQ_WORKER)) {
+		WARN_ON_ONCE(1);
+		set_bit(XPRT_CLOSE_WAIT, &xprt->state);
+		return;
+	}
 
 	if (atomic_read(&transport->xprt.swapper))
 		sk_clear_memalloc(sk);
@@ -1302,7 +1312,7 @@ static void xs_reset_transport(struct so
 	mutex_unlock(&transport->recv_mutex);
 
 	trace_rpc_socket_close(xprt, sock);
-	fput(filp);
+	__fput_sync(filp);
 
 	xprt_disconnect_done(xprt);
 }