From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756912AbZKSWWw (ORCPT ); Thu, 19 Nov 2009 17:22:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755925AbZKSWWv (ORCPT ); Thu, 19 Nov 2009 17:22:51 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:59599 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755808AbZKSWWu (ORCPT ); Thu, 19 Nov 2009 17:22:50 -0500 To: Tetsuo Handa Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, john.johansen@canonical.com 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> From: ebiederm@xmission.com (Eric W. Biederman) Date: Thu, 19 Nov 2009 14:22:53 -0800 In-Reply-To: <200911200717.CDF87535.JQMSFFtOFVOHOL@I-love.SAKURA.ne.jp> (Tetsuo Handa's message of "Fri\, 20 Nov 2009 07\:17\:53 +0900") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in02.mta.xmission.com;;;ip=76.21.114.89;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 76.21.114.89 X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Version: 4.2.1 (built Thu, 25 Oct 2007 00:26:12 +0000) X-SA-Exim-Scanned: No (on in02.mta.xmission.com); Unknown failure Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Eric