Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757235AbXKFMXr (ORCPT ); Tue, 6 Nov 2007 07:23:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755599AbXKFMXi (ORCPT ); Tue, 6 Nov 2007 07:23:38 -0500 Received: from rv-out-0910.google.com ([209.85.198.186]:44233 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751079AbXKFMXh (ORCPT ); Tue, 6 Nov 2007 07:23:37 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=AUeUgydhUcglX2ZBwVEaxDwU9goHEYSUiVg9HTigUXVpHR5Ar8wWunbol1z+IkifUHgx1tFccHGJQyFOHGhh+bLcI0vxmu4bTUkGQVOvYLshQowOsAm41xTosaqe/RC1J/AihxEIJfBm/6bIxQ56GqLkmZBLAS1pya8bxXgKYK8= Message-ID: <1865922a0711060423ue81dbdct413b993e727f6f9@mail.gmail.com> Date: Tue, 6 Nov 2007 14:23:36 +0200 From: "Ahmed S. Darwish" To: "Adrian Bunk" Subject: Re: [PATCH] Smackv10: Smack rules grammar + their stateful parser Cc: "Kyle Moffett" , "Casey Schaufler" , akpm@osdl.org, torvalds@osdl.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20071106114738.GH26163@stusta.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <472B8DAF.9080706@schaufler-ca.com> <20071103164303.GA26707@ubuntu> <20071106063305.GA26163@stusta.de> <20071106085651.GC26163@stusta.de> <20071106113359.GA6041@ubuntu> <20071106114738.GH26163@stusta.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2801 Lines: 67 On 11/6/07, Adrian Bunk wrote: > On Tue, Nov 06, 2007 at 01:34:05PM +0200, Ahmed S. Darwish wrote: > > Hi, > > > > On Tue, Nov 06, 2007 at 09:56:51AM +0100, Adrian Bunk wrote: > > > On Tue, Nov 06, 2007 at 03:26:12AM -0500, Kyle Moffett wrote: > > > > On Nov 06, 2007, at 01:33:05, Adrian Bunk wrote: > > > >> Can you limit this to 7bit ASCII and use isascii() somewhere? > > > >> > > > >> Otherwise I'd expect funny things to happen when you e.g. use isspace() on > > > >> the UTF-8 encoded character ??. > > > > > > > > Actually, you don't need to. You tell them it expects UTF-8 encoded > > > > strings and be done with it. All US-ASCII characters from 0 through 127 > > > > (IE: high bit clear) are exactly the same in UTF-8, and UTF-8 special > > > > characters have the high bit set in all bytes. Therefore you just assume > > > > that anything with the high bit set is part of a word and you can handle > > > > basic UTF-8. (It doesn't work on special UTF-8 space characters like > > > > nonbreaking space and similar, but handling those is significantly more > > > > complicated). > > > > > > The documentations says: > > > "Smack labels cannot contain unprintable characters or the "/" (slash) > > > character." > > > > > > What you propose might contain unprintable characters, and it might even > > > be invalid UTF-8. > > > > As far as I understand the problem now, isspace() accepts the 0xa0 > > character which might collide with some of UTF-8 encoded characters > > cause the high bit is set. > > > > I used "if (!isspace(c) && !isgraph(c)) return -EINVAL;" to test > > rules' characters validity which seems not enough. I'll add !isascii(c) > > in the condition and ask Casey to change the documentation to be > > something like: > > > > Smack labels are represented in ASCII characters, they cannot contain > > unprintable characters or the '/' (slash) character. > > > > and in write(): > > if (!isascii(c) return -EINVAL; > > if (!isspace(c) && !isgraph(c)) return -EINVAL; > > > > This satisfy above customized labels rule, right ? > > It should work for all charsets you'll usually have to handle. > I admit I'm not experienced in such encoding stuff, but shouldn't the ASCII and the ASCII-compatible UTF-8 encodings be enough for the labels ? > It would not work if someone would e.g. give you UTF-16 encoded strings, > but I don't see this happening in practice. Won't this complicate the code too much ? -- Ahmed S. Darwish Homepage: http://darwish.07.googlepages.com Blog: http://darwish-07.blogspot.com - 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/