From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759474Ab2JYM5w (ORCPT ); Thu, 25 Oct 2012 08:57:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58697 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754050Ab2JYM5v (ORCPT ); Thu, 25 Oct 2012 08:57:51 -0400 Date: Thu, 25 Oct 2012 18:27:32 +0530 (IST) From: P J P X-X-Sender: pjp@javelin.pnq.redhat.com To: Tetsuo Handa cc: keescook@chromium.org, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, josh@joshtriplett.org, serge.hallyn@canonical.com, linux-fsdevel@vger.kernel.org, me@halfdog.net Subject: Re: [PATCH] exec: do not leave bprm->interp on stack In-Reply-To: <201210252103.BJG56875.OtHFLOOVSFFQMJ@I-love.SAKURA.ne.jp> Message-ID: References: <20121024232032.GA31129@www.outflux.net> <20121025041620.GH2616@ZenIV.linux.org.uk> <201210252103.BJG56875.OtHFLOOVSFFQMJ@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Tetsuo, +-- On Thu, 25 Oct 2012, Tetsuo Handa wrote --+ | Excuse me, but why do you change definition of printable(c) ? | Looks like a regression. #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) Earlier definition of printable() as above was used to - break; - out of the loop when (c) was either tab or new line or any printable character. Whereas, in the patch it is used to call the request_module routine if the (c) is printable character, and hence the change to - printable(). | Wouldn't your patch trigger call request_module() whenever a script | starting with "#!/bin/sh" is executed? Yes, Petr(a colleague here) already pointed out about excessive call to request_module() routine, in case if the requested module is already loaded or is not required/available. I'm trying to find a possible fix for the same. Is there a way to to see if the requested module 'binfmt-xxxx' is accessible or not? The call to - request_module - could be conditioned accordingly. Thank you. -- Prasad J Pandit / Red Hat Security Response Team DB7A 84C5 D3F9 7CD1 B5EB C939 D048 7860 3655 602B