Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753083Ab3I0Ieo (ORCPT ); Fri, 27 Sep 2013 04:34:44 -0400 Received: from numidia.opendz.org ([98.142.220.152]:54253 "EHLO numidia.opendz.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750852Ab3I0Iel (ORCPT ); Fri, 27 Sep 2013 04:34:41 -0400 Date: Fri, 27 Sep 2013 09:34:35 +0100 From: Djalal Harouni To: Linus Torvalds Cc: "Eric W. Biederman" , Kees Cook , Al Viro , Andrew Morton , Ingo Molnar , "Serge E. Hallyn" , Cyrill Gorcunov , LKML , linux-fsdevel , "kernel-hardening@lists.openwall.com" , tixxdz@gmail.com Subject: Re: [PATCH 04/12] seq_file: Make seq_file able to access the file's opener cred Message-ID: <20130927083435.GA2340@dztty> References: <1380140085-29712-1-git-send-email-tixxdz@opendz.org> <1380140085-29712-5-git-send-email-tixxdz@opendz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1899 Lines: 53 On Wed, Sep 25, 2013 at 05:22:51PM -0700, Linus Torvalds wrote: > On Wed, Sep 25, 2013 at 1:14 PM, Djalal Harouni wrote: > > > > Therefor add the f_cred field to the seq_file struct and a helper > > seq_f_cred() to return it. > > I hate how you've split up this patch from the next one that actually > _initializes_ the new field. > > The two patches should have been one. Ok, noted. > I think the patch should also remove the 'user_ns' member, since it's > now available as f_cred->user_ns. > > I also suspect that it would be better to just make the the new > seq_file member point to the 'struct file' instead. Sure, it's an > extra level of indirection, but the lifetime of f_cred is not as clear > otherwise. You don't increment the reference count, which is correct > *only* because 'seq_file' has the same lifetime as 'struct file', and > thus the reference count from struct file for the f_cred is > sufficient. Yes. For the seq_file struct, yes we can make it point to the 'struct file'. Or, I've also found other ways, perhaps they will make Al happy, one of them is to use the 'struct file' as you point, but in an other way, or change the file_operations of these sensitive files. Please Linus see my next response to Al, thanks > [ Time passes, I look over the other patches ] > > Oh, and I note that you remove user_ns in patch 12. Again, I think > that's just splitting things up too much. It actually gets harder to > see what happens when you do this. Ok, will improve it. Will also wait to see what others think, then resend as a V2 Thanks. > > Linus -- Djalal Harouni http://opendz.org -- 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/