ksmbd: add reserved room in ipc request/response

Whenever new parameter is added to smb configuration, It is possible
to break the execution of the IPC daemon by mismatch size of
request/response. This patch tries to reserve space in ipc request/response
in advance to prevent that.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: namjaejeon

fs/ksmbd/ksmbd_netlink.h

@@ -104,6 +104,7 @@ struct ksmbd_startup_request {
 					 */
 	__u32	sub_auth[3];		/* Subauth value for Security ID */
 	__u32	smb2_max_credits;	/* MAX credits */
+	__u32	reserved[128];		/* Reserved room */
 	__u32	ifc_list_sz;		/* interfaces list size */
 	__s8	____payload[];
 };
@@ -114,7 +115,7 @@ struct ksmbd_startup_request {
  * IPC request to shutdown ksmbd server.
  */
 struct ksmbd_shutdown_request {
-	__s32	reserved;
+	__s32	reserved[16];
 };
 
 /*
@@ -123,6 +124,7 @@ struct ksmbd_shutdown_request {
 struct ksmbd_login_request {
 	__u32	handle;
 	__s8	account[KSMBD_REQ_MAX_ACCOUNT_NAME_SZ]; /* user account name */
+	__u32	reserved[16];				/* Reserved room */
 };
 
 /*
@@ -136,6 +138,7 @@ struct ksmbd_login_response {
 	__u16	status;
 	__u16	hash_sz;			/* hash size */
 	__s8	hash[KSMBD_REQ_MAX_HASH_SZ];	/* password hash */
+	__u32	reserved[16];			/* Reserved room */
 };
 
 /*
@@ -144,6 +147,7 @@ struct ksmbd_login_response {
 struct ksmbd_share_config_request {
 	__u32	handle;
 	__s8	share_name[KSMBD_REQ_MAX_SHARE_NAME]; /* share name */
+	__u32	reserved[16];		/* Reserved room */
 };
 
 /*
@@ -158,6 +162,7 @@ struct ksmbd_share_config_response {
 	__u16	force_directory_mode;
 	__u16	force_uid;
 	__u16	force_gid;
+	__u32	reserved[128];		/* Reserved room */
 	__u32	veto_list_sz;
 	__s8	____payload[];
 };
@@ -188,6 +193,7 @@ struct ksmbd_tree_connect_request {
 	__s8	account[KSMBD_REQ_MAX_ACCOUNT_NAME_SZ];
 	__s8	share[KSMBD_REQ_MAX_SHARE_NAME];
 	__s8	peer_addr[64];
+	__u32	reserved[16];		/* Reserved room */
 };
 
 /*
@@ -197,6 +203,7 @@ struct ksmbd_tree_connect_response {
 	__u32	handle;
 	__u16	status;
 	__u16	connection_flags;
+	__u32	reserved[16];		/* Reserved room */
 };
 
 /*
@@ -205,6 +212,7 @@ struct ksmbd_tree_connect_response {
 struct ksmbd_tree_disconnect_request {
 	__u64	session_id;	/* session id */
 	__u64	connect_id;	/* tree connection id */
+	__u32	reserved[16];	/* Reserved room */
 };
 
 /*
@@ -213,6 +221,7 @@ struct ksmbd_tree_disconnect_request {
 struct ksmbd_logout_request {
 	__s8	account[KSMBD_REQ_MAX_ACCOUNT_NAME_SZ]; /* user account name */
 	__u32	account_flags;
+	__u32	reserved[16];				/* Reserved room */
 };
 
 /*