From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: sys_kcmp Date: Mon, 24 Sep 2012 13:44:47 -0700 Message-ID: <87bogvup4w.fsf@xmission.com> References: <20120922114549.GA11610@moon> <20120922132046.GA4260@flint.arm.linux.org.uk> <20120922114723.d7f07fb6.akpm@linux-foundation.org> <1348503709.20929.40.camel@deneb.redhat.com> <20120924164942.GH16532@moon> <20120924174256.GD24172@moon> <87lifzuvey.fsf@xmission.com> <20120924185119.GI16532@moon> <20120924203512.GF24172@moon> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]:40504 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757707Ab2IXUo4 (ORCPT ); Mon, 24 Sep 2012 16:44:56 -0400 In-Reply-To: <20120924203512.GF24172@moon> (Cyrill Gorcunov's message of "Tue, 25 Sep 2012 00:35:12 +0400") Sender: linux-arch-owner@vger.kernel.org List-ID: To: Cyrill Gorcunov Cc: Mark Salter , Andrew Morton , Russell King , Geert Uytterhoeven , Kees Cook , linux-kernel@vger.kernel.org, Linux-Arch , Heiko Carstens , "H. Peter Anvin" , Pavel Emelyanov Cyrill Gorcunov writes: > On Mon, Sep 24, 2012 at 10:51:19PM +0400, Cyrill Gorcunov wrote: >> > I expect what you want is a call to access_ok, rather than hard coding >> > details about task layout here. This test certainly looks wrong >> > for a 32bit process on a 64bit kernel. If I read your test right it >> > appears I can set values of say 0x100000000 on a 32bit process... >> > >> > As for mmap_min_addr I would expect your find_vma check would make that >> > test unnecessary, simply by not finding a vma... >> >> Good point, Eric, thanks! I'm cooking a new patch now. > > Btw, Eric, I somehow miss one bit -- how would you set this 0x100000000 > if TASK_SIZE is a macro which does check for TIF_ADDR32 and sets limit > acordingly? What i'm missing? How odd. Last time I had looked TASK_SIZE was a simple constant. Still I wonder a little if all architectures currently run from 0 to TASK_SIZE, for address space available. I seem to remember there have been some exceptions to that rule. But I can't recall what they were. Eric