From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756061Ab3JITMz (ORCPT ); Wed, 9 Oct 2013 15:12:55 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:55858 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754491Ab3JITMw (ORCPT ); Wed, 9 Oct 2013 15:12:52 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Miklos Szeredi Cc: "Serge E. Hallyn" , Al Viro , Linux-Fsdevel , Kernel Mailing List , Andy Lutomirski , Rob Landley , Linus Torvalds References: <87a9kkax0j.fsf@xmission.com> <8761v7h2pt.fsf@tw-ebiederman.twitter.com> <87li281wx6.fsf_-_@xmission.com> <874n8w1wsz.fsf_-_@xmission.com> <20131008155041.GI14242@tucsk.piliscsaba.szeredi.hu> <877gdne8pr.fsf@xmission.com> Date: Wed, 09 Oct 2013 12:12:41 -0700 In-Reply-To: <877gdne8pr.fsf@xmission.com> (Eric W. Biederman's message of "Tue, 08 Oct 2013 14:47:12 -0700") Message-ID: <8761t65kd2.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+YpLzbH+dX3VnOpFHtjWLnFs7RaezZUGQ= X-SA-Exim-Connect-IP: 98.207.154.105 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0073] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa07 1397; Body=1 Fuz1=1 Fuz2=1] * 1.2 XMSubMetaSxObfu_03 Obfuscated Sexy Noun-People * 1.0 XMSubMetaSx_00 1+ Sexy Words X-Spam-DCC: XMission; sa07 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Miklos Szeredi X-Spam-Relay-Country: Subject: Grrrr fusermount. 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 in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ebiederm@xmission.com (Eric W. Biederman) writes: > But I will go through and read the old fusermount code before I get too > much farther just so I understand what I am potentially breaking. Grr. So I have just read the fusermount umount code and the hack that it uses before there was UMOUNT_NOFOLLOW support in the vm. If I walk this path of lazy unmounts and detaching directories, anyone with a new kernel and an old copy of fusermount and a nfs mounted home directory will be able to exploit the fusermount umount symlink race. Unless we can declare that old fusermount binaries are buggy beyond supporting this patchset as it exists is dead. Eric