Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758979AbZCPScm (ORCPT ); Mon, 16 Mar 2009 14:32:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758682AbZCPScY (ORCPT ); Mon, 16 Mar 2009 14:32:24 -0400 Received: from mummy.ncsc.mil ([144.51.88.129]:47033 "EHLO mummy.ncsc.mil" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757959AbZCPScX (ORCPT ); Mon, 16 Mar 2009 14:32:23 -0400 Subject: Re: =?UTF-8?Q?=D0=9E=D1=82=D0=B2=D0=B5=D1=82=3A?= VFS, NFS security bug? Should CAP_MKNOD and CAP_LINUX_IMMUTABLE be added to CAP_FS_MASK? From: Stephen Smalley To: "Serge E. Hallyn" Cc: Igor Zhbanov , "J. Bruce Fields" , Michael Kerrisk , linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, neilb@suse.de, Trond.Myklebust@netapp.com, David Howells , Andrew Morgan , James Morris , linux-security-module@vger.kernel.org, SELinux In-Reply-To: <20090313190002.GA16025@us.ibm.com> References: <20090311232356.GP13540@fieldses.org> <20090312161047.GA15209@us.ibm.com> <517f3f820903121321sf6d2014q8165b925d5d44db7@mail.gmail.com> <20090313175848.GB27891@fieldses.org> <20090313190002.GA16025@us.ibm.com> Content-Type: text/plain Organization: National Security Agency Date: Mon, 16 Mar 2009 14:21:45 -0400 Message-Id: <1237227705.1035.93.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.24.5 (2.24.5-1.fc10) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1886 Lines: 41 On Fri, 2009-03-13 at 14:00 -0500, Serge E. Hallyn wrote: > Quoting Igor Zhbanov (izh1979@gmail.com): > > But ordinary users can't create devices. It seems to me that in time > > of implementation of capabilities in kernel 2.4, capabilities related > > to filesystem was added first. And mark for them contains all above in > > header file. And when CAP_MKNOD was added later, author just forget to > > update mask. > > > > If mask was designed to drop all filesystem related capabilities, then > > it must be expanded, because ordinary users cannot create devices etc. > > I think you thought Bruce was saying we shouldn't change the set of > capabilities, but he was just asking exactly what changes Michael was > interested in. > > Igor, thanks for finding this. I never got your original message. Do > you have a patdch to add the two capabilities? Do you think the > other two I mentioned (CAP_SYS_ADMIN and CAP_SETFCAP) need to be > added too? > > I've added Andrew Morgan, LSM and SELinux mailing lists to get another > opinion about adding those two. In particular, we'd be adding them > to the fs_masks becuase CAP_SYS_ADMIN lets you change the selinux > label, and CAP_SETFCAP lets you change the file capabilities. I'd be inclined against adding CAP_SYS_ADMIN to the mask; note that it is only checked for setting SELinux security contexts (or more broadly any attributes in the security namespace) when SELinux is disabled. In the SELinux-enabled case, we are checking SELinux-specific permissions when setting the SELinux attributes, whether on the client or the server. -- Stephen Smalley National Security Agency -- 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/