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=-4.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=ham 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 B375CC282CE for ; Wed, 22 May 2019 18:29:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8484C21473 for ; Wed, 22 May 2019 18:29:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gS+RIag0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729496AbfEVS3u (ORCPT ); Wed, 22 May 2019 14:29:50 -0400 Received: from mail-yb1-f195.google.com ([209.85.219.195]:44402 "EHLO mail-yb1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728272AbfEVS3u (ORCPT ); Wed, 22 May 2019 14:29:50 -0400 Received: by mail-yb1-f195.google.com with SMTP id x187so1223935ybc.11; Wed, 22 May 2019 11:29:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mNNHt7Z7ll37muKTAxbqGIESLdms47B625sz6OwZ88M=; b=gS+RIag0j1EGY4wDhlTvibyOVNteJNKXBPtsOrOJesByGKR2Fuq4X6RhDbSo7QH9G7 KRnjke+GG3lc/4hxqh+KFtbvDMsLtpoByk3G9G8bwzcCfXJ2oCg77JRACh+DJK9pNMMk RLYATRv8sU5DYSau9IUY3RI9CJ39VKRVdaLY2VsFEK9DBxvGidv7KL+DMtB/ZMPcVk9s QZYPOM95xYbSo4RUkc8DpcXZ0tMFqnwQA5omAqkTeBvxW1wUTSS36oS6w8xdvbIVtv6u Wc/2FDQqA02lI2Q288EkKNN1QjLX2K/gxQu326Gp+Fytagqqoe7JZko5HPTqeKZYUrrY SMQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mNNHt7Z7ll37muKTAxbqGIESLdms47B625sz6OwZ88M=; b=ZZ1EVHgKZ71q2KiuMpLGemlyUCyWWhD1k6/7Y/kVr5GDR0aLcaAA4yK8/x/Z5uHzO+ 70emQQWl0ALBLev/Hf5LIHHbLKmWO2SSs2s28JKpu7p3akkcpIOI4IT88n9yghpEraBO VQpDXBm1h0Z3VkDRxEuf+zp4XorBA0QkQup73XftlfoeGywy3GSetm0V0Y1OyLR2HKMq exlChj6YmSLcY7RpCIUJWyjrL9BaDrYn9shGkb9Z6/GMxmZGucDl00MrWeuzFLQgJUky qXAY+kKhsRJzQDECHdeg3eKa/9UyQt5qGyJazV9AWyxViqPROQPNEw7offO15NuYckII 4XqQ== X-Gm-Message-State: APjAAAXsvPeEorRiNQNx9fUynwoM+y1nvTeuHa0g2CQXD7Flfq9hwKRP 0hnYaWtdJwNjPDUD0OUt7kIbDt+wC0/aQPc3XvkpPCfx X-Google-Smtp-Source: APXvYqwsTkDSAsunnEIlGONN4y6SZSOWtqPzl+D0bsrRFAxyHTFt36u4qhuOcQFbp+BFEDxOaiKXidJf8gQKIuEp7oM= X-Received: by 2002:a25:a081:: with SMTP id y1mr15975318ybh.428.1558549789253; Wed, 22 May 2019 11:29:49 -0700 (PDT) MIME-Version: 1.0 References: <20190522163150.16849-1-christian@brauner.io> In-Reply-To: <20190522163150.16849-1-christian@brauner.io> From: Amir Goldstein Date: Wed, 22 May 2019 21:29:37 +0300 Message-ID: Subject: Re: [PATCH] fanotify: remove redundant capable(CAP_SYS_ADMIN)s To: Christian Brauner Cc: Jan Kara , linux-fsdevel , linux-kernel Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 22, 2019 at 7:32 PM Christian Brauner wrote: > > This removes two redundant capable(CAP_SYS_ADMIN) checks from > fanotify_init(). > fanotify_init() guards the whole syscall with capable(CAP_SYS_ADMIN) at the > beginning. So the other two capable(CAP_SYS_ADMIN) checks are not needed. It's intentional: commit e7099d8a5a34d2876908a9fab4952dabdcfc5909 Author: Eric Paris Date: Thu Oct 28 17:21:57 2010 -0400 fanotify: limit the number of marks in a single fanotify group There is currently no limit on the number of marks a given fanotify group can have. Since fanotify is gated on CAP_SYS_ADMIN this was not seen as a serious DoS threat. This patch implements a default of 8192, the same as inotify to work towards removing the CAP_SYS_ADMIN gating and eliminating the default DoS'able status. Signed-off-by: Eric Paris There idea is to eventually remove the gated CAP_SYS_ADMIN. There is no reason that fanotify could not be used by unprivileged users to setup inotify style watch on an inode or directories children, see: https://patchwork.kernel.org/patch/10668299/ > > Fixes: 5dd03f55fd2 ("fanotify: allow userspace to override max queue depth") > Fixes: ac7e22dcfaf ("fanotify: allow userspace to override max marks") Fixes is used to tag bug fixes for stable. There is no bug. Thanks, Amir.