Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754952Ab1BVScc (ORCPT ); Tue, 22 Feb 2011 13:32:32 -0500 Received: from mail3.caviumnetworks.com ([12.108.191.235]:8721 "EHLO mail3.caviumnetworks.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754786Ab1BVScb (ORCPT ); Tue, 22 Feb 2011 13:32:31 -0500 Message-ID: <4D640133.9020901@caviumnetworks.com> Date: Tue, 22 Feb 2011 10:32:19 -0800 From: David Daney User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Fedora/3.0.10-1.fc12 Thunderbird/3.0.10 MIME-Version: 1.0 To: Kees Cook CC: linux-kernel@vger.kernel.org, Eugene Teo , Ralph Campbell , Roland Dreier , Sean Hefty , Hal Rosenstock , Jeremy Fitzhardinge , Konrad Rzeszutek Wilk , Alexander Viro , Greg Kroah-Hartman , Miklos Szeredi , "J. Bruce Fields" , Neil Brown , Matthew Wilcox , James Morris , Stephen Smalley , Eric Paris , Nick Piggin , Arnd Bergmann , Ian Campbell , Jarkko Sakkinen , Tejun Heo , Casey Schaufler Subject: Re: [PATCH 2/2] debugfs: only allow root access to debugging interfaces References: <1298398198-18482-1-git-send-email-kees.cook@canonical.com> <1298398198-18482-2-git-send-email-kees.cook@canonical.com> <20110222181613.GU4000@outflux.net> In-Reply-To: <20110222181613.GU4000@outflux.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 22 Feb 2011 18:32:24.0984 (UTC) FILETIME=[D9CC1180:01CBD2BE] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2170 Lines: 59 On 02/22/2011 10:16 AM, Kees Cook wrote: > Har har, I forgot --compose to "git send-email". > > Anyway, with the continuing deluge of bugs in the "debug" filesystem, I > would like to make that filesystem's root directory mode 0700 by default > since it's filled with crazy stuff that regular users do not need to see. > > Better to try to just close the door completely on all the stuff in there. > It is, after all, supposed to only be used for debugging, right? > It depends if you consider use of ftrace and kprobes 'debugging'. In any event, you really have to be root to be able to manipulate them. I can currently do 'cat /sys/kernel/debug/tracing/trace' as a normal user. With your change I don't think it would be possible. This is not something I often (ever) do, but it is a change. David Daney > -Kees > > On Tue, Feb 22, 2011 at 10:09:58AM -0800, Kees Cook wrote: >> Block access to the potentially dangerous debugging interfaces in >> the debugfs filesystem. >> >> Signed-off-by: Kees Cook >> --- >> fs/debugfs/inode.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c >> index 3cb33c3..83c61a3 100644 >> --- a/fs/debugfs/inode.c >> +++ b/fs/debugfs/inode.c >> @@ -133,7 +133,7 @@ static int debug_fill_super(struct super_block *sb, void *data, int silent) >> static struct tree_descr debug_files[] = {{""}}; >> >> return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files, >> - S_IWUSR | S_IRUGO | S_IXUGO); >> + S_IRWXU); >> } >> >> static struct dentry *debug_mount(struct file_system_type *fs_type, >> -- >> 1.7.2.3 >> >> -- >> 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/ -- 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/