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=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,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 38E10C4708F for ; Wed, 2 Jun 2021 09:16:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 221AB60FE3 for ; Wed, 2 Jun 2021 09:16:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231670AbhFBJSY (ORCPT ); Wed, 2 Jun 2021 05:18:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:47436 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229603AbhFBJSU (ORCPT ); Wed, 2 Jun 2021 05:18:20 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1F55260FE3; Wed, 2 Jun 2021 09:16:34 +0000 (UTC) Date: Wed, 2 Jun 2021 11:16:32 +0200 From: Christian Brauner To: Jakub Kicinski Cc: Changbin Du , Alexander Viro , "David S. Miller" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, stable@vger.kernel.org, Cong Wang , David Laight Subject: Re: [PATCH] nsfs: fix oops when ns->ops is not provided Message-ID: <20210602091632.qijrpc2z6z44wu54@wittgenstein> References: <20210531153410.93150-1-changbin.du@gmail.com> <20210531220128.26c0cb36@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> <20210601080654.cl7caplm7rsagl6u@wittgenstein> <20210601132602.02e92678@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210601132602.02e92678@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 01, 2021 at 01:26:02PM -0700, Jakub Kicinski wrote: > On Tue, 1 Jun 2021 10:06:54 +0200 Christian Brauner wrote: > > > I'm not sure why we'd pick runtime checks for something that can be > > > perfectly easily solved at compilation time. Networking should not > > > be asking for FDs for objects which don't exist. > > > > Agreed! > > This should be fixable by sm like: > > > > diff --git a/net/socket.c b/net/socket.c > > index 27e3e7d53f8e..2484466d96ad 100644 > > --- a/net/socket.c > > +++ b/net/socket.c > > @@ -1150,10 +1150,12 @@ static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg) > > break; > > case SIOCGSKNS: > > err = -EPERM; > > +#ifdef CONFIG_NET_NS > > if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) > > break; > > > > err = open_related_ns(&net->ns, get_net_ns); > > +#endif > > break; > > case SIOCGSTAMP_OLD: > > case SIOCGSTAMPNS_OLD: > > Thanks! You weren't CCed on v1, so FWIW I was suggesting > checking in get_net_ns(), to catch other callers: > > diff --git a/net/socket.c b/net/socket.c > index 27e3e7d53f8e..3b44f2700e0c 100644 > --- a/net/socket.c > +++ b/net/socket.c > @@ -1081,6 +1081,8 @@ static long sock_do_ioctl(struct net *net, struct socket *sock, > > struct ns_common *get_net_ns(struct ns_common *ns) > { > + if (!IS_ENABLED(CONFIG_NET_NS)) > + return ERR_PTR(-EOPNOTSUPP); > return &get_net(container_of(ns, struct net, ns))->ns; > } > EXPORT_SYMBOL_GPL(get_net_ns); Yeah, that's better than my hack. :) Maybe this function should simply move over to net/core/net_namespace.c with the other netns getters, e.g. get_net_ns_by_fd()? #ifdef CONFIG_NET_NS [...] struct net *get_net_ns_by_fd(int fd) { struct file *file; struct ns_common *ns; struct net *net; file = proc_ns_fget(fd); if (IS_ERR(file)) return ERR_CAST(file); ns = get_proc_ns(file_inode(file)); if (ns->ops == &netns_operations) net = get_net(container_of(ns, struct net, ns)); else net = ERR_PTR(-EINVAL); fput(file); return net; } #else struct net *get_net_ns_by_fd(int fd) { return ERR_PTR(-EINVAL); } #endif EXPORT_SYMBOL_GPL(get_net_ns_by_fd); Christian