From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757385AbZKSWfK (ORCPT ); Thu, 19 Nov 2009 17:35:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757162AbZKSWfJ (ORCPT ); Thu, 19 Nov 2009 17:35:09 -0500 Received: from adelie.canonical.com ([91.189.90.139]:55483 "EHLO adelie.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757092AbZKSWfI (ORCPT ); Thu, 19 Nov 2009 17:35:08 -0500 Message-ID: <4B05C817.9020705@canonical.com> Date: Thu, 19 Nov 2009 14:35:03 -0800 From: John Johansen Organization: Canonical User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: "Eric W. Biederman" CC: Tetsuo Handa , linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: Re: [PATCH 00/23] Removal of binary sysctl support References: <200911190704.CHI18293.VJOMHFtOLQSOFF@I-love.SAKURA.ne.jp> <200911192333.EHB57391.FSQOHOJtMFFLVO@I-love.SAKURA.ne.jp> <200911200717.CDF87535.JQMSFFtOFVOHOL@I-love.SAKURA.ne.jp> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Eric W. Biederman wrote: > Tetsuo Handa writes: > >> Hello. >> >> Eric W. Biederman wrote: >>>> Indeed. TOMOYO and AppArmor need a hint for prepending "/proc" prefix. >>>> A simple implementation which adds one bit to task_struct is shown below. >>>> In this way, not only the file permission checks inside dentry_open() >>>> but also the directory permission checks inside vfs_path_lookup() can be >>>> prepended "/proc" prefix. AppArmor might want to prepend "/proc" inside >>>> vfs_path_lookup(). >>> There don't appear to be any security hooks in vfs_path_lookup(). >>> >> OK. Then, AppArmor won't be confused. >> >>> Instead of current->in_sysctl we can just look at the path and see if >>> it is the root of the mount chain and if the fs is proc. >>> >>> Something like: >>> >>> diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c >>> index 5f2e332..0b55faa 100644 >>> --- a/security/tomoyo/realpath.c >>> +++ b/security/tomoyo/realpath.c >>> @@ -108,6 +108,15 @@ int tomoyo_realpath_from_path2(struct path *path, char *newname, >>> spin_unlock(&dcache_lock); >>> path_put(&root); >>> path_put(&ns_root); >>> + /* Prepend "/proc" prefix if using internal proc vfs mount. */ >>> + if (!IS_ERR(sp) && (path->mnt->mnt_parent == path->mnt) && >>> + (strcmp(path->mnt->mnt_sb->s_type->name, "proc") == 0)) { >>> + sp -= 5; >>> + if (sp >= newname) >>> + memcpy(sp, "/proc", 5); >>> + else >>> + sp = ERR_PTR(-ENOMEM); >>> + } >>> } >>> if (IS_ERR(sp)) >>> error = PTR_ERR(sp); >> Above patch works. Please proceed. Thank you. >> >> Acked-by: Tetsuo Handa >> >> Why not to use path->mnt->mnt_sb->s_magic == PROC_SUPER_MAGIC rather than >> strcmp(path->mnt->mnt_sb->s_type->name, "proc") == 0 ? > > Brain short circuit. > The patch look good to me too. Acked-by: John Johansen