From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 42786 invoked by alias); 29 May 2017 09:48:45 -0000 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Received: (qmail 42627 invoked by uid 89); 29 May 2017 09:48:39 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-7.0 required=5.0 tests=AWL,BAYES_00,GIT_PATCH_2,NORMAL_HTTP_TO_IP,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=PROBLEM, asks, H*F:D*nl, userid X-HELO: lb3-smtp-cloud2.xs4all.net Received: from lb3-smtp-cloud2.xs4all.net (HELO lb3-smtp-cloud2.xs4all.net) (194.109.24.29) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 29 May 2017 09:48:36 +0000 Received: from webmail.xs4all.nl ([IPv6:2001:888:0:22:194:109:20:217]) by smtp-cloud2.xs4all.net with ESMTP id S9oW1v0090nKt58019oWrb; Mon, 29 May 2017 11:48:30 +0200 Received: from a83-162-234-136.adsl.xs4all.nl ([83.162.234.136]) by webmail.xs4all.nl with HTTP (HTTP/1.1 POST); Mon, 29 May 2017 11:48:30 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 29 May 2017 11:39:00 -0000 From: Houder To: cygwin@cygwin.com Subject: Re: openssh: privilege separation no longer supported on Cygwin? In-Reply-To: <37b863f6-ce5c-ef13-569f-8044fe485075@gmail.com> References: <37b863f6-ce5c-ef13-569f-8044fe485075@gmail.com> Message-ID: <20e2702ca3837f5d54c558f8e786c717@xs4all.nl> X-Sender: houder@xs4all.nl User-Agent: XS4ALL Webmail X-IsSubscribed: yes X-SW-Source: 2017-05/txt/msg00470.txt.bz2 On 2017-05-29 10:39, Marco Atzeri wrote: > On 29/05/2017 07:23, Houder wrote: [snip] >> ... because, that is, I think, what I am seeing: >> >> - the userid of child sshd is still 'cyg_server' ... >> - and I get an elevated shell when I login ... >> >> Not what I expected ... >> >> Gr. Henri >> > > Hi Houder, > please read the last Announcement > > https://sourceware.org/ml/cygwin-announce/2017-03/msg00028.html [snip] > It seems you misunderstood the communication: > - the possibility to NOT use "privilege separation" is deprecated > - "privilege separation" will became mandatory Hi Marco, Sorry for the misunderstanding. Yes, to my knowledge, PS, privilege separation, is now mandatory (using a new mechanism under Linux [1]). [1] sandboxing? Because of PS, I expect to see an UNprivileged sshd process talking to the user process (where the ssh command has been executed). But above all, I expect an UNelevated shell when I login in ... However, what I get after login (after providing my credentials) is an ELEVATED shell (yes, Administrators is part of the group set). Now I wonder if this happens because I do NOT observe PS. Look below, please ... After executing the ssh command, ssh asks for my credentials ... in stead of providing my credentials, I execute the ps command in a second terminal. To my surprise, the grandchild of the listener is executed using "cyg_server" and not "sshd" ... Currently, I am looking at: https://cygwin.com/cygwin-ug-net/ntsec.html#ntsec-setuid-overview Regards, Henri ----- - pre-authentication: Shell 1: 64-@@ ssh -p 222 -l Henri 192.168.178.15 Enter passphrase for key '/home/Henri/.ssh/id_rsa': <==== passphrase not yet entered Shell 2: (observer) 64-@@# ps -af UID PID PPID TTY STIME COMMAND Henri 2308 4356 pty0 11:01:41 /usr/bin/ssh Henri 5092 176 pty1 11:01:58 /usr/bin/ps Henri 4356 3744 pty0 10:57:56 /usr/bin/bash Henri 3744 1 ? 10:57:50 /usr/bin/mintty-273 Henri 176 4604 pty1 10:58:21 /usr/bin/bash cyg_serv 4992 2476 ? 11:01:03 /usr/sbin/sshd privileged listener cyg_serv 2476 1 ? 11:01:03 /usr/bin/cygrunsrv Henri 4604 1 ? 10:58:21 /usr/bin/mintty-273 cyg_serv 1496 3032 ? 11:01:42 /usr/sbin/sshd should be using sshd as userid cyg_serv 3032 4992 ? 11:01:42 /usr/sbin/sshd privileged monitor (child of listener) - post-authentication: Shell 1: 64-@@ ssh -p 222 -l Henri 192.168.178.15 Enter passphrase for key '/home/Henri/.ssh/id_rsa': <==== passphrase has been entered Last login: Mon May 29 10:07:00 2017 from 192.168.178.15 64-@@# <===== ///// PROBLEM: this shell is ELEVATED ///// Shell 2: (observer) 64-@@# ps -af UID PID PPID TTY STIME COMMAND Henri 2496 3032 pty3 11:02:31 /usr/bin/bash remote shell (but it is an elevated shell! ?????) Henri 2308 4356 pty0 11:01:41 /usr/bin/ssh Henri 4356 3744 pty0 10:57:56 /usr/bin/bash Henri 3744 1 ? 10:57:50 /usr/bin/mintty-273 Henri 176 4604 pty1 10:58:21 /usr/bin/bash cyg_serv 4992 2476 ? 11:01:03 /usr/sbin/sshd privileged listener Henri 4996 176 pty1 11:06:05 /usr/bin/ps cyg_serv 2476 1 ? 11:01:03 /usr/bin/cygrunsrv Henri 4604 1 ? 10:58:21 /usr/bin/mintty-273 cyg_serv 3032 4992 ? 11:01:42 /usr/sbin/sshd privileged monitor (child of listener) ===== -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple