From owner-svn-src-all@freebsd.org Mon May 15 19:40:54 2017 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B0E1DD6EE8D; Mon, 15 May 2017 19:40:54 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (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 217A81F10; Mon, 15 May 2017 19:40:53 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.15.2/8.15.2) with ESMTPS id v4FJenI3004804 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 15 May 2017 22:40:49 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua v4FJenI3004804 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id v4FJenlb004803; Mon, 15 May 2017 22:40:49 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Mon, 15 May 2017 22:40:49 +0300 From: Konstantin Belousov To: Nikolai Lifanov Cc: Alexey Dokuchaev , svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Ian Lepore Subject: Re: svn commit: r318313 - head/libexec/rtld-elf Message-ID: <20170515194049.GJ1622@kib.kiev.ua> References: <201705151848.v4FImwMW070221@repo.freebsd.org> <20170515185236.GB1637@FreeBSD.org> <20170515190030.GG1622@kib.kiev.ua> <1494875335.59865.118.camel@freebsd.org> <20170515192529.GH1622@kib.kiev.ua> <20170515193609.GC28684@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.8.2 (2017-04-18) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on tom.home X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 15 May 2017 19:40:54 -0000 On Mon, May 15, 2017 at 03:37:42PM -0400, Nikolai Lifanov wrote: > On 05/15/2017 15:36, Alexey Dokuchaev wrote: > > On Mon, May 15, 2017 at 10:25:29PM +0300, Konstantin Belousov wrote: > >> On Mon, May 15, 2017 at 01:08:55PM -0600, Ian Lepore wrote: > >>> Well, for example, it seems like it would allow anyone to execute a > >>> binary even if the sysadmin had set it to -x specifically to prevent > >>> people from running it. > >> > >> The direct mode does not (and cannot) honor set{u,g}id modes of the > >> executable, so any binary run this way would only exercise the existing > >> power of the user which did it. > >> > >> The most advanced explanation that I was given in private was among > >> the lines: "if you have an environment where users can upload content > >> to a shared server, but have no access to chmod(2), no compilers, no > >> scripting languages, etc." The person then admitted that (s)he does not > >> consider it as an actual concern. > > > > Would this now allow executing binaries (with or without +x bit) from > > filesystems mounted with -o noexec? > > > > ./danfe > > No: > > # zfs create -o mountpoint=/mnt -o exec=off tank/TEST > # cp /bin/sh /mnt/ > # /mnt/sh > /mnt/sh: Permission denied. > # /libexec/ld-elf.so.1 /mnt/sh > /mnt/sh: mmap of data failed: Permission denied This is due to r313967 | kib | 2017-02-19 22:51:04 +0200 (Sun, 19 Feb 2017) | 24 lines Apply noexec mount option for mmap(PROT_EXEC).