FAILED: patch "[PATCH] ksmbd: fix use-after-free in __smb2_lease_break_noti()" failed to apply to 6.1-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.1-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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025042110-bovine-triangle-a138@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@kernel.org>
Date: Fri, 11 Apr 2025 15:19:46 +0900
Subject: [PATCH] ksmbd: fix use-after-free in __smb2_lease_break_noti()

Move tcp_transport free to ksmbd_conn_free. If ksmbd connection is
referenced when ksmbd server thread terminates, It will not be freed,
but conn->tcp_transport is freed. __smb2_lease_break_noti can be performed
asynchronously when the connection is disconnected. __smb2_lease_break_noti
calls ksmbd_conn_write, which can cause use-after-free
when conn->ksmbd_transport is already freed.

Cc: stable@vger.kernel.org
Reported-by: Norbert Szetei <norbert@doyensec.com>
Tested-by: Norbert Szetei <norbert@doyensec.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c
index c1f22c129111..83764c230e9d 100644
--- a/fs/smb/server/connection.c
+++ b/fs/smb/server/connection.c
@@ -39,8 +39,10 @@ void ksmbd_conn_free(struct ksmbd_conn *conn)
 	xa_destroy(&conn->sessions);
 	kvfree(conn->request_buf);
 	kfree(conn->preauth_info);
-	if (atomic_dec_and_test(&conn->refcnt))
+	if (atomic_dec_and_test(&conn->refcnt)) {
+		ksmbd_free_transport(conn->transport);
 		kfree(conn);
+	}
 }
 
 /**
diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c
index 7f38a3c3f5bd..abedf510899a 100644
--- a/fs/smb/server/transport_tcp.c
+++ b/fs/smb/server/transport_tcp.c
@@ -93,15 +93,19 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk)
 	return t;
 }
 
+void ksmbd_free_transport(struct ksmbd_transport *kt)
+{
+	struct tcp_transport *t = TCP_TRANS(kt);
+
+	sock_release(t->sock);
+	kfree(t->iov);
+	kfree(t);
+}
+
 static void free_transport(struct tcp_transport *t)
 {
 	kernel_sock_shutdown(t->sock, SHUT_RDWR);
-	sock_release(t->sock);
-	t->sock = NULL;
-
 	ksmbd_conn_free(KSMBD_TRANS(t)->conn);
-	kfree(t->iov);
-	kfree(t);
 }
 
 /**
diff --git a/fs/smb/server/transport_tcp.h b/fs/smb/server/transport_tcp.h
index 8c9aa624cfe3..1e51675ee1b2 100644
--- a/fs/smb/server/transport_tcp.h
+++ b/fs/smb/server/transport_tcp.h
@@ -8,6 +8,7 @@
 
 int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz);
 struct interface *ksmbd_find_netdev_name_iface_list(char *netdev_name);
+void ksmbd_free_transport(struct ksmbd_transport *kt);
 int ksmbd_tcp_init(void);
 void ksmbd_tcp_destroy(void);