Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752979Ab2HBNBm (ORCPT ); Thu, 2 Aug 2012 09:01:42 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:56700 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750994Ab2HBNBj (ORCPT ); Thu, 2 Aug 2012 09:01:39 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Alan Cox Cc: Ludwig Nussel , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jan Kara (maintainer:EXT2 FILE SYSTEM), Rob Landley (maintainer:DOCUMENTATION), Andrew Morton (maintainer:EXT3 FILE SYSTEM), Andreas Dilger (maintainer:EXT3 FILE SYSTEM), "Theodore Ts'o" (maintainer:EXT4 FILE SYSTEM), linux-ext4@vger.kernel.org (open list:EXT2 FILE SYSTEM), linux-doc@vger.kernel.org (open list:DOCUMENTATION) References: <1343908443-17369-1-git-send-email-ludwig.nussel@suse.de> <1343908443-17369-2-git-send-email-ludwig.nussel@suse.de> <20120802130642.46b12c59@pyramind.ukuu.org.uk> Date: Thu, 02 Aug 2012 06:00:55 -0700 In-Reply-To: <20120802130642.46b12c59@pyramind.ukuu.org.uk> (Alan Cox's message of "Thu, 2 Aug 2012 13:06:42 +0100") Message-ID: <87629130u0.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-SPF: eid=;;;mid=;;;hst=in01.mta.xmission.com;;;ip=98.207.153.68;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18GVDh9oSK7RNI1v3saMKTI/Ts272fkBQI= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.1 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -0.0 BAYES_20 BODY: Bayes spam probability is 5 to 20% * [score: 0.1244] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa05 1397; Body=1 Fuz1=1 Fuz2=1] * 2.2 XMSubMetaSxObfu_03 Obfuscated Sexy Noun-People * 1.6 XMSubMetaSx_00 1+ Sexy Words X-Spam-DCC: XMission; sa05 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ****;Alan Cox X-Spam-Relay-Country: Subject: Re: [PATCH 1/3] implement uid and gid mount options for ext2 X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Fri, 06 Aug 2010 16:31:04 -0600) 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 Content-Length: 1147 Lines: 26 Alan Cox writes: >> +uid=n[:m] Make all files appear to belong to uid n. >> + Useful for e.g. removable media with fstab >> + options 'user,uid=useruid'. The optional second >> + uid m is actually written to the file system. > > So what happens if I insert a USB key containing a device node to the > hard disk ? Why is this functionality useful in the current form ? > > (ie I think you need an actual rational security model first) > Also why is this at the per fs level duplicating stuff each time rather > than at the vfs level - this seems to be vfs level functionality. Even more fun there is essentially a generic implementation in the user namespaces. What needs to be implemented to support this is support for mounting in a non-default user namespace, and then all of the mapping functionality is generic. Which I presume will imply MS_NODEV. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/