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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 62641C433DB for ; Wed, 10 Mar 2021 18:23:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3827964EE2 for ; Wed, 10 Mar 2021 18:23:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229503AbhCJSWz (ORCPT ); Wed, 10 Mar 2021 13:22:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54066 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232330AbhCJSWf (ORCPT ); Wed, 10 Mar 2021 13:22:35 -0500 Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4344BC061763; Wed, 10 Mar 2021 10:22:35 -0800 (PST) Received: by mail-wr1-x434.google.com with SMTP id f12so24418111wrx.8; Wed, 10 Mar 2021 10:22:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=0tu0NOYXG5WtYq99GHSm2YwfcjxiU16vCremGU2p31M=; b=msrZbGOkD2Isy+rMP3gosek7d/5Ozb7lUf27/4sF5bbF9OwqLjnXD0NvLnjwMd/ghv 9HVXvBjT45hF7YiYoasLftHXnZPmv0SV+EvbivID+JhdhpkS2DufWMq4q6qqhpQ0ihIT RGCCX0kPp22eCEK1WFaDQmMfxHPy2qILrEfeUT0T5dITOC//FpPbZyNVvogUxBeAB6xF if1AtuLYu4dCU8yH8jS170JhOqCD2GdswACelTdmvMEMQeHJRRo5sKPLfsRRAOBMdYMq SYTy4vtq25z2Pa1womKzSP6m/2dPpnO7B/i1iAjg00oe6mKjCSJ8BcjDe8Cz1TrphyDi BIoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=0tu0NOYXG5WtYq99GHSm2YwfcjxiU16vCremGU2p31M=; b=Q/m9ihpNBO2LZFpK7LyRQQ7ORvG/MoRECBrq2CiTLG07ov/hr6yXsWTmetFwebGHpi lZTOAGUFhtec9YDUhBe+JX+Y9tq/KCF0qSgcS6Y+JlM3Fnw/jJEPgzzqdPKAcEzS94XC OPQpEXGHwSuOg3F+RDj3db+xPyKxvntM04k02tUjb82kovcUrhm/EFNIVDNBHb84tJrW zl1UaJcMdbC98x3eGwjllyIwfJdqU5zuWfKbIziC9vx72EHBn0iV6gWrZ75q0EKAdafb 0hZ2fBoHzhqMZf6SImvFVbaDRvYVSdFFIdpe24/3uOaNdgdQlUXtpyyhRW6ubZvom20/ lMlw== X-Gm-Message-State: AOAM531sXT5Ky3ooHxXzw3MhgyaILsgTbkl/8T9MqnbKe0O0a/8yI+mq uJpiVUfm5so4v4RLoGvgmuOOfowHkED0+w== X-Google-Smtp-Source: ABdhPJxG/1k3ueSD/MuHuHMA0j8g6uldaZDdS3GEXdoHvNRqrkyPTnGtbP855tMpG7EUzMg6EsCcMw== X-Received: by 2002:a05:6000:1546:: with SMTP id 6mr4810464wry.398.1615400554048; Wed, 10 Mar 2021 10:22:34 -0800 (PST) Received: from example.org (ip-94-113-225-162.net.upcbroadband.cz. [94.113.225.162]) by smtp.gmail.com with ESMTPSA id m132sm223239wmf.45.2021.03.10.10.22.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Mar 2021 10:22:33 -0800 (PST) Date: Wed, 10 Mar 2021 19:22:29 +0100 From: Alexey Gladkov To: "Eric W. Biederman" Cc: LKML , Linux FS Devel , Alexander Viro , Kees Cook Subject: Re: [RESEND PATCH v4 0/3] proc: Relax check of mount visibility Message-ID: <20210310182229.dynrgsxejnfkp3f2@example.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Feb 22, 2021 at 09:44:40AM -0600, Eric W. Biederman wrote: > Alexey Gladkov writes: > > > If only the dynamic part of procfs is mounted (subset=pid), then there is no > > need to check if procfs is fully visible to the user in the new user > > namespace. > > > A couple of things. > > 1) Allowing the mount should come in the last patch. So we don't have a > bisect hazard. > > 2) We should document that we still require a mount of proc to match on > atime and readonly mount attributes. Ok. I will try to do it in v5. > 3) If we can find a way to safely not require a previous mount of proc > this will be much more valuable. True, but for now I have no idea how to do it. I would prefer to move in small steps. -- Rgrds, legion