From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9089C433E3 for ; Tue, 21 Jul 2020 17:10:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC22E2065D for ; Tue, 21 Jul 2020 17:10:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729865AbgGURKk (ORCPT ); Tue, 21 Jul 2020 13:10:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728692AbgGURKk (ORCPT ); Tue, 21 Jul 2020 13:10:40 -0400 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E67F4C061794; Tue, 21 Jul 2020 10:10:39 -0700 (PDT) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jxvmm-00HKD7-K6; Tue, 21 Jul 2020 17:10:36 +0000 Date: Tue, 21 Jul 2020 18:10:36 +0100 From: Al Viro To: Christoph Hellwig Cc: Linus Torvalds , Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org Subject: Re: [PATCH 16/24] init: add an init_chroot helper Message-ID: <20200721171036.GX2786714@ZenIV.linux.org.uk> References: <20200721162818.197315-1-hch@lst.de> <20200721162818.197315-17-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200721162818.197315-17-hch@lst.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 21, 2020 at 06:28:10PM +0200, Christoph Hellwig wrote: > +int __init init_chroot(const char *filename) > +{ > + struct path path; > + int error; > + > + error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); > + if (error) > + return error; > + error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); Matter of taste, but if we do that, I wonder if we would be better off with error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); if (!error && !ns_capable(current_user_ns(), CAP_SYS_CHROOT)) error = -EPERM; if (!error) error = security_path_chroot(&path); if (!error) set_fs_root(current->fs, &path); path_put(&path); return error;