From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933133Ab3CMSf3 (ORCPT ); Wed, 13 Mar 2013 14:35:29 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:43096 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756411Ab3CMSf2 (ORCPT ); Wed, 13 Mar 2013 14:35:28 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Kees Cook Cc: Sebastian Krahmer , linux-kernel@vger.kernel.org, Oleg Nesterov , Linux Containers References: <20130313175729.GH12501@outflux.net> Date: Wed, 13 Mar 2013 11:35:15 -0700 In-Reply-To: <20130313175729.GH12501@outflux.net> (Kees Cook's message of "Wed, 13 Mar 2013 10:57:29 -0700") Message-ID: <87r4jjkv18.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX1+bMz/SpYMrXTVBlGugiULUdbyloLsOeVo= X-SA-Exim-Connect-IP: 208.54.5.253 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 TR_Symld_Words too many words that have symbols inside * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa03 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa03 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Kees Cook X-Spam-Relay-Country: Subject: Re: CLONE_NEWUSER|CLONE_FS root exploit X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Wed, 14 Nov 2012 14:26:46 -0700) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kees Cook writes: > Hi, > > It seem like we should block (at least) this combination. On 3.9, this > exploit works once uidmapping is added. > > http://www.openwall.com/lists/oss-security/2013/03/13/10 Yes. That is a bad combination. It let's chroot confuse privileged processes. Now to figure out if this is easier to squash by adding a user_namespace to fs_struct or by just forbidding this combination. Eric