From owner-freebsd-hackers@freebsd.org Sun Oct 7 19:08:18 2018 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 78D2A10C9C5C for ; Sun, 7 Oct 2018 19:08:18 +0000 (UTC) (envelope-from yuripv@yuripv.net) Received: from wout2-smtp.messagingengine.com (wout2-smtp.messagingengine.com [64.147.123.25]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id F05B6901AB for ; Sun, 7 Oct 2018 19:08:17 +0000 (UTC) (envelope-from yuripv@yuripv.net) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.west.internal (Postfix) with ESMTP id 84034187 for ; Sun, 7 Oct 2018 15:08:16 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute5.internal (MEProxy); Sun, 07 Oct 2018 15:08:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yuripv.net; h= subject:from:to:references:message-id:date:mime-version :in-reply-to:content-type:content-transfer-encoding; s=fm3; bh=b xRP/f0gU5CvWEmVj0Q0qVzT4EKKXORm61xLCRGCP3Y=; b=RyOB7rl+iRONt5Ez0 bNRwiO0f0cFzVnZAorTw1n1rBfbqRCYmpnDiaYOvKTZIYntX3PoUovnd2yZVn1vt jtHL+JTCcSEX8dUhSLBKkovx/CfA9XrsdhELgGq7SoEETYmrWPqgo2swciZJ4XzP zDwGIS4bFb+edaNmW1A1S9b4FE2zwZhRgfwHiivaWCGF3l28ehVAcXrCnlS/1P0n DfgKRUoBWaxCC/YGpGFq2EMc17GCUasjdpkNuzjLxgZ46ZY/1L40kmhxcNgQi3Ny j+81CMnmSIyhKBe7vmTnFBSyR8Yes8qIVZ3fhtHrH+wIbBa7MJFkfD9RAIQnvS+n LWYbA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm3; bh=bxRP/f0gU5CvWEmVj0Q0qVzT4EKKXORm61xLCRGCP 3Y=; b=rcdg6uyiPTEE7fUfrBlD3ou1SMV5r0uwBo2Y+jRYu97bOHfwtfZo0R0wx vbhlmwWtZype7PDkI2YSEfRe6bh7scTdt5r7yHxfaUIBegY8G0kezw8v/ECilhwN nbhVfStBAKai29lCdWtLhfLE0a+Hj+9zk5PU7deXjmmHwYwnK7NM6WzvzBH9niz+ nMxN7TVPSOSvZe4hCqxymCFC3HQ1ihpeGfuluLtNOsKlB2uYKZGABNlTKvVztXp7 B6l9GlzYXQmGXxNNRE/n+OcnoMZoh22F5t7HrM9N9kz6+ZQPFWXlGY7VFWKrh8DZ so4DA5TVzZY7GTrKijo6LwhFsRHAg== X-ME-Sender: X-ME-Proxy: Received: from [192.168.1.2] (unknown [62.183.124.173]) by mail.messagingengine.com (Postfix) with ESMTPA id 164AF102DE for ; Sun, 7 Oct 2018 15:08:14 -0400 (EDT) Subject: Re: vfs.usermount allows users to do arbitrary unmounts From: Yuri Pankov To: freebsd-hackers References: Message-ID: <4c5d948d-f129-2787-1f34-8e4fd96d7144@yuripv.net> Date: Sun, 7 Oct 2018 22:08:11 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 07 Oct 2018 19:08:18 -0000 Yuri Pankov wrote: > Hi, > > Going through https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=232021, > I noticed that unmount(2) will not fail with EPERM as expected on mounts > that don't belong to the user, and which were not mounted by that user, > e.g.: > > # zfs create data/test > # ls -ld /data/test > drwxr-xr-x  2 root  wheel  2 Oct  7 21:55 /data/test > $ umount /data/test; echo $? > 0 > > Even if vfs.usermount isn't great from security perspective, is this > expected? Nevermind me, looks like I got it all confused with using `zfs allow`.