FAILED: patch "[PATCH] ksmbd: fix extended session security negotiation for raw" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 6868f857514bbfd2ed10b9b566664dc4a8ca039d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026110305-blimp-nape-e4b2@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6868f857514bbfd2ed10b9b566664dc4a8ca039d Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@kernel.org>
Date: Sun, 4 Oct 2026 09:42:27 +0900
Subject: [PATCH] ksmbd: fix extended session security negotiation for raw
 NTLMSSP

ksmbd_build_ntlmssp_challenge_blob() only advertises extended session
security when conn->use_spnego is true. As a result, raw NTLMSSP
negotiation drops NTLMSSP_NEGOTIATE_EXTENDED_SEC from the challenge even
when the client requested it.

A Windows capture shows an initial SPNEGO authentication succeeding,
followed by a raw NTLMSSP negotiation on the same TCP connection. The raw
challenge omits extended session security, and the client does not send
an AUTHENTICATE message. The unfinished session then occupies the pending
session slot, causing subsequent SESSION_SETUP requests to fail with
STATUS_INSUFFICIENT_RESOURCES.

Set NTLMSSP_NEGOTIATE_EXTENDED_SEC whenever the client requests it,
independently of the SPNEGO wrapper, as required by [MS-NLMP].

Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Cc: stable@vger.kernel.org
Reported-by: Tea La Forgia <tealaforgia+alias@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

diff --git a/fs/smb/server/auth.c b/fs/smb/server/auth.c
index 1b24eb3f3998..88953315b160 100644
--- a/fs/smb/server/auth.c
+++ b/fs/smb/server/auth.c
@@ -336,8 +336,7 @@ ksmbd_build_ntlmssp_challenge_blob(struct challenge_message *chgblob,
 	if (cflags & NTLMSSP_REQUEST_TARGET)
 		flags |= NTLMSSP_REQUEST_TARGET;
 
-	if (conn->use_spnego &&
-	    (cflags & NTLMSSP_NEGOTIATE_EXTENDED_SEC))
+	if (cflags & NTLMSSP_NEGOTIATE_EXTENDED_SEC)
 		flags |= NTLMSSP_NEGOTIATE_EXTENDED_SEC;
 
 	if (cflags & NTLMSSP_NEGOTIATE_KEY_XCH)