Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755053AbaA1MR0 (ORCPT ); Tue, 28 Jan 2014 07:17:26 -0500 Received: from mail-pa0-f44.google.com ([209.85.220.44]:57318 "EHLO mail-pa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754948AbaA1MRX (ORCPT ); Tue, 28 Jan 2014 07:17:23 -0500 MIME-Version: 1.0 In-Reply-To: <20140128120432.GA26347@gmail.com> References: <20140126122729.32113.19659.stgit@warthog.procyon.org.uk> <20140126201928.GA8224@gmail.com> <20140126202509.GA10275@gmail.com> <20140128120432.GA26347@gmail.com> Date: Tue, 28 Jan 2014 13:17:22 +0100 X-Google-Sender-Auth: Y3w1RlLosdziZTlwbm1rz7DcIKw Message-ID: Subject: Re: [PATCH] afs: proc cells and rootcell are writeable From: Geert Uytterhoeven To: Ingo Molnar , Joe Perches Cc: Linus Torvalds , David Howells , Linux Kernel Mailing List , linux-afs@lists.infradead.org, =?UTF-8?Q?Pali_Roh=C3=A1r?= , Alexey Dobriyan Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 28, 2014 at 1:04 PM, Ingo Molnar wrote: > * Geert Uytterhoeven wrote: >> On Sun, Jan 26, 2014 at 9:25 PM, Ingo Molnar wrote: >> > * Ingo Molnar wrote: >> >> * Linus Torvalds wrote: >> >> > On Sun, Jan 26, 2014 at 4:27 AM, David Howells wrote: >> >> > > - p = proc_create("cells", 0, proc_afs, &afs_proc_cells_fops); >> >> > > + p = proc_create("cells", S_IFREG | S_IRUGO | S_IWUSR, proc_afs, &afs_proc_cells_fops); >> >> > > - p = proc_create("rootcell", 0, proc_afs, &afs_proc_rootcell_fops); >> >> > > + p = proc_create("rootcell", S_IFREG | S_IRUGO | S_IWUSR, proc_afs, &afs_proc_rootcell_fops); >> >> > >> >> > So the S_IFREG isn't necessary. >> >> > >> >> > And quite frankly, I personally think S_IRUGO | S_IWUSR is _less_ >> >> > readable than 0644. It's damn hard to parse those random letter >> >> > combinations, and at least I have to really think about it, in a way >> >> > that the octal representation does *not* make me go "I have to think >> >> > about that". >> >> > >> >> > So my personal preference would be to just see that simple 0644 in >> >> > proc_create. Hmm? >> >> >> >> Perhaps we could also generate the most common variants as: >> >> >> >> #define PERM__rw_r__r__ 0644 >> >> #define PERM__r________ 0400 >> >> #define PERM__r__r__r__ 0444 >> >> #define PERM__r_xr_xr_x 0555 >> >> I like it (also without the PERM prefix, cfr. Alexey's old patch). >> >> >> or something similar, more or less matching the output of 'ls -l'? >> > >> > Another variant of this would be to do the following macro: >> > >> > PERM(R_X, R_X, R_X) >> > PERM(R__, R__, R__) >> > PERM(RW_, R__, R__) >> >> IMHO, this is again less outstanding. >> >> > With the advantage of separating the groups better and reducing the >> > number of constants needed. >> >> Only a limited number of combinations is in active use, right? > > Correct - and in fact that kind of limitation is also a security > feature: using patterns _outside_ of the typical, already defined > group of permission patterns would in itself be a 'is that really > justified?' red flag during review. Then Joe (CCed :-) can write a checkpatch rule to flag all new users of the I_S[RWX}* flags.., > I'm fine with Alexey's shorter variant as well. > > Would someone be interested in sending a real patch for it, defining a > usable set of initial flags such as 0644, 0444, 0555 and 0600? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- 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/