[PATCH 6.6.y] ksmbd: fix use-after-free in __smb2_lease_break_noti()

[Sasha Levin <sashal@kernel.org>]

From: Namjae Jeon <linkinjeon@kernel.org>

[ Upstream commit 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de ]

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>
[ Removed declaration of non-existent function ksmbd_find_netdev_name_iface_list() from transport_tcp.h. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/server/connection.c    |  4 +++-
 fs/smb/server/transport_tcp.c | 14 +++++++++-----
 fs/smb/server/transport_tcp.h |  1 +
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c
index e7bcc3830031..abbf756891a9 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 2ce7f75059cb..c27f0cef3b59 100644
--- a/fs/smb/server/transport_tcp.c
+++ b/fs/smb/server/transport_tcp.c
@@ -93,17 +93,21 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk)
 	return t;
 }
 
-static void free_transport(struct tcp_transport *t)
+void ksmbd_free_transport(struct ksmbd_transport *kt)
 {
-	kernel_sock_shutdown(t->sock, SHUT_RDWR);
-	sock_release(t->sock);
-	t->sock = NULL;
+	struct tcp_transport *t = TCP_TRANS(kt);
 
-	ksmbd_conn_free(KSMBD_TRANS(t)->conn);
+	sock_release(t->sock);
 	kfree(t->iov);
 	kfree(t);
 }
 
+static void free_transport(struct tcp_transport *t)
+{
+	kernel_sock_shutdown(t->sock, SHUT_RDWR);
+	ksmbd_conn_free(KSMBD_TRANS(t)->conn);
+}
+
 /**
  * kvec_array_init() - initialize a IO vector segment
  * @new:	IO vector to be initialized
diff --git a/fs/smb/server/transport_tcp.h b/fs/smb/server/transport_tcp.h
index e338bebe322f..5925ec5df475 100644
--- a/fs/smb/server/transport_tcp.h
+++ b/fs/smb/server/transport_tcp.h
@@ -7,6 +7,7 @@
 #define __KSMBD_TRANSPORT_TCP_H__
 
 int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz);
+void ksmbd_free_transport(struct ksmbd_transport *kt);
 int ksmbd_tcp_init(void);
 void ksmbd_tcp_destroy(void);
 
-- 
2.39.5