Patch "SUNRPC: timeout and cancel TLS handshake with -ETIMEDOUT" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    SUNRPC: timeout and cancel TLS handshake with -ETIMEDOUT

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sunrpc-timeout-and-cancel-tls-handshake-with-etimedo.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 5fd40b31e790001995d49bebfe4b7fbcf8be0dc0
Author: Benjamin Coddington <bcodding@xxxxxxxxxx>
Date:   Fri Nov 15 08:59:36 2024 -0500

    SUNRPC: timeout and cancel TLS handshake with -ETIMEDOUT
    
    [ Upstream commit d7bdd849ef1b681da03ac05ca0957b2cbe2d24b6 ]
    
    We've noticed a situation where an unstable TCP connection can cause the
    TLS handshake to timeout waiting for userspace to complete it.  When this
    happens, we don't want to return from xs_tls_handshake_sync() with zero, as
    this will cause the upper xprt to be set CONNECTED, and subsequent attempts
    to transmit will be returned with -EPIPE.  The sunrpc machine does not
    recover from this situation and will spin attempting to transmit.
    
    The return value of tls_handshake_cancel() can be used to detect a race
    with completion:
    
     * tls_handshake_cancel - cancel a pending handshake
     * Return values:
     *   %true - Uncompleted handshake request was canceled
     *   %false - Handshake request already completed or not found
    
    If true, we do not want the upper xprt to be connected, so return
    -ETIMEDOUT.  If false, its possible the handshake request was lost and
    that may be the reason for our timeout.  Again we do not want the upper
    xprt to be connected, so return -ETIMEDOUT.
    
    Ensure that we alway return an error from xs_tls_handshake_sync() if we
    call tls_handshake_cancel().
    
    Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
    Reviewed-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Fixes: 75eb6af7acdf ("SUNRPC: Add a TCP-with-TLS RPC transport class")
    Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 714da627fba8e..c528297245125 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2596,11 +2596,10 @@ static int xs_tls_handshake_sync(struct rpc_xprt *lower_xprt, struct xprtsec_par
 	rc = wait_for_completion_interruptible_timeout(&lower_transport->handshake_done,
 						       XS_TLS_HANDSHAKE_TO);
 	if (rc <= 0) {
-		if (!tls_handshake_cancel(sk)) {
-			if (rc == 0)
-				rc = -ETIMEDOUT;
-			goto out_put_xprt;
-		}
+		tls_handshake_cancel(sk);
+		if (rc == 0)
+			rc = -ETIMEDOUT;
+		goto out_put_xprt;
 	}
 
 	rc = lower_transport->xprt_err;