From patchwork Fri Jul 24 00:12:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Dmitry V. Levin" X-Patchwork-Id: 11681855 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0279014E3 for ; Fri, 24 Jul 2020 00:12:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD28F2086A for ; Fri, 24 Jul 2020 00:12:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728230AbgGXAMv (ORCPT ); Thu, 23 Jul 2020 20:12:51 -0400 Received: from vmicros1.altlinux.org ([194.107.17.57]:56654 "EHLO vmicros1.altlinux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728187AbgGXAMv (ORCPT ); Thu, 23 Jul 2020 20:12:51 -0400 Received: from mua.local.altlinux.org (mua.local.altlinux.org [192.168.1.14]) by vmicros1.altlinux.org (Postfix) with ESMTP id E3DF072CCDC; Fri, 24 Jul 2020 03:12:48 +0300 (MSK) Received: by mua.local.altlinux.org (Postfix, from userid 508) id B5F297CFF73; Fri, 24 Jul 2020 03:12:48 +0300 (MSK) Date: Fri, 24 Jul 2020 03:12:48 +0300 From: "Dmitry V. Levin" To: Alexander Viro , Serge Hallyn , Andrei Vagin , "Eric W. Biederman" Cc: =?utf-8?b?w4Frb3M=?= Uzonyi , Arnd Bergmann , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] fs/nsfs.c: fix ioctl support of compat processes Message-ID: <20200724001248.GC25522@altlinux.org> MIME-Version: 1.0 Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org According to Documentation/driver-api/ioctl.rst, in order to support 32-bit user space running on a 64-bit kernel, each subsystem or driver that implements an ioctl callback handler must also implement the corresponding compat_ioctl handler. The compat_ptr_ioctl() helper can be used in place of a custom compat_ioctl file operation for drivers that only take arguments that are pointers to compatible data structures. In case of NS_* ioctls only NS_GET_OWNER_UID accepts an argument, and this argument is a pointer to uid_t type, which is universally defined to __kernel_uid32_t. This change fixes compat strace --pidns-translation. Note: when backporting this patch to stable kernels, commit "compat_ioctl: add compat_ptr_ioctl()" is needed as well. Reported-by: Ákos Uzonyi Fixes: 6786741dbf99 ("nsfs: add ioctl to get an owning user namespace for ns file descriptor") Cc: stable@vger.kernel.org # v4.9+ Signed-off-by: Dmitry V. Levin --- fs/nsfs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/nsfs.c b/fs/nsfs.c index 800c1d0eb0d0..a00236bffa2c 100644 --- a/fs/nsfs.c +++ b/fs/nsfs.c @@ -21,6 +21,7 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl, static const struct file_operations ns_file_operations = { .llseek = no_llseek, .unlocked_ioctl = ns_ioctl, + .compat_ioctl = compat_ptr_ioctl, }; static char *ns_dname(struct dentry *dentry, char *buffer, int buflen)