ksmbd: add free_transport ops in ksmbd connection

free_transport function for tcp connection can be called from smbdirect.
It will cause kernel oops. This patch add free_transport ops in ksmbd
connection, and add each free_transports for tcp and smbdirect.

Fixes: 21a4e47 ("ksmbd: fix use-after-free in __smb2_lease_break_noti()")
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: namjaejeon

fs/smb/server/connection.c

@@ -40,7 +40,7 @@ void ksmbd_conn_free(struct ksmbd_conn *conn)
 	kvfree(conn->request_buf);
 	kfree(conn->preauth_info);
 	if (atomic_dec_and_test(&conn->refcnt)) {
-		ksmbd_free_transport(conn->transport);
+		conn->transport->ops->free_transport(conn->transport);
 		kfree(conn);
 	}
 }

fs/smb/server/connection.h

@@ -133,6 +133,7 @@ struct ksmbd_transport_ops {
 			  void *buf, unsigned int len,
 			  struct smb2_buffer_desc_v1 *desc,
 			  unsigned int desc_len);
+	void (*free_transport)(struct ksmbd_transport *kt);
 };
 
 struct ksmbd_transport {

fs/smb/server/transport_rdma.c

@@ -159,7 +159,8 @@ struct smb_direct_transport {
 };
 
 #define KSMBD_TRANS(t) ((struct ksmbd_transport *)&((t)->transport))
-
+#define SMBD_TRANS(t)	((struct smb_direct_transport *)container_of(t, \
+				struct smb_direct_transport, transport))
 enum {
 	SMB_DIRECT_MSG_NEGOTIATE_REQ = 0,
 	SMB_DIRECT_MSG_DATA_TRANSFER
@@ -410,6 +411,11 @@ static struct smb_direct_transport *alloc_transport(struct rdma_cm_id *cm_id)
 	return NULL;
 }
 
+static void smb_direct_free_transport(struct ksmbd_transport *kt)
+{
+	kfree(SMBD_TRANS(kt));
+}
+
 static void free_transport(struct smb_direct_transport *t)
 {
 	struct smb_direct_recvmsg *recvmsg;
@@ -455,7 +461,6 @@ static void free_transport(struct smb_direct_transport *t)
 
 	smb_direct_destroy_pools(t);
 	ksmbd_conn_free(KSMBD_TRANS(t)->conn);
-	kfree(t);
 }
 
 static struct smb_direct_sendmsg
@@ -2281,4 +2286,5 @@ static const struct ksmbd_transport_ops ksmbd_smb_direct_transport_ops = {
 	.read		= smb_direct_read,
 	.rdma_read	= smb_direct_rdma_read,
 	.rdma_write	= smb_direct_rdma_write,
+	.free_transport = smb_direct_free_transport,
 };

fs/smb/server/transport_tcp.c

@@ -93,7 +93,7 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk)
 	return t;
 }
 
-void ksmbd_free_transport(struct ksmbd_transport *kt)
+static void ksmbd_tcp_free_transport(struct ksmbd_transport *kt)
 {
 	struct tcp_transport *t = TCP_TRANS(kt);
 
@@ -656,4 +656,5 @@ static const struct ksmbd_transport_ops ksmbd_tcp_transport_ops = {
 	.read		= ksmbd_tcp_read,
 	.writev		= ksmbd_tcp_writev,
 	.disconnect	= ksmbd_tcp_disconnect,
+	.free_transport = ksmbd_tcp_free_transport,
 };