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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 5AF77C33CAF for ; Mon, 13 Jan 2020 13:31:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3141721734 for ; Mon, 13 Jan 2020 13:31:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728731AbgAMNbG (ORCPT ); Mon, 13 Jan 2020 08:31:06 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:50722 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726074AbgAMNbF (ORCPT ); Mon, 13 Jan 2020 08:31:05 -0500 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1iqznr-007J3N-Qf; Mon, 13 Jan 2020 13:30:47 +0000 Date: Mon, 13 Jan 2020 13:30:47 +0000 From: Al Viro To: Ian Kent Cc: Aleksa Sarai , David Howells , Eric Biederman , Linus Torvalds , stable@vger.kernel.org, Christian Brauner , Serge Hallyn , dev@opencontainers.org, containers@lists.linux-foundation.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 0/1] mount: universally disallow mounting over symlinks Message-ID: <20200113133047.GR8904@ZenIV.linux.org.uk> References: <20200101030815.GA17593@ZenIV.linux.org.uk> <20200101144407.ugjwzk7zxrucaa6a@yavin.dot.cyphar.com> <20200101234009.GB8904@ZenIV.linux.org.uk> <20200102035920.dsycgxnb6ba2jhz2@yavin.dot.cyphar.com> <20200103014901.GC8904@ZenIV.linux.org.uk> <20200110231945.GL8904@ZenIV.linux.org.uk> <20200113035407.GQ8904@ZenIV.linux.org.uk> <41c535d689530f3715f21cd25074eb61e825a5f6.camel@themaw.net> <58f9894e51a00ad2a4ac3d4122bf29e7cb6c0d54.camel@themaw.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <58f9894e51a00ad2a4ac3d4122bf29e7cb6c0d54.camel@themaw.net> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Jan 13, 2020 at 02:03:00PM +0800, Ian Kent wrote: > Oh wait, for systemd I was actually looking at: > https://github.com/systemd/systemd/blob/master/src/shared/switch-root.c > > > > > Mind you, that's not the actual systemd repo. either I probably > > need to look a lot deeper (and at the actual systemd repo) to > > work out what's actually being called. > > > > > Sigh... Guess I'll have to dig that Fedora KVM image out and > > > try to see what it's about... ;-/ Here comes a couple of hours > > > of build... D'oh... And yes, that would've been a bisect hazard - switch to path_lookupat() later in the series gets rid of that. Incremental (to be foldede, of course): diff --git a/fs/namei.c b/fs/namei.c index 1793661c3342..204677c37751 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2634,7 +2634,7 @@ path_mountpoint(struct nameidata *nd, unsigned flags, struct path *path) (err = lookup_last(nd)) > 0) { s = trailing_symlink(nd); } - if (!err) + if (!err && (nd->flags & LOOKUP_RCU)) err = unlazy_walk(nd); if (!err) err = handle_lookup_down(nd);