From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750962AbeEAVqH (ORCPT ); Tue, 1 May 2018 17:46:07 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55858 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750743AbeEAVqG (ORCPT ); Tue, 1 May 2018 17:46:06 -0400 Date: Tue, 1 May 2018 14:46:04 -0700 From: Andrew Morton To: Laura Abbott Cc: Dave Anderson , Kees Cook , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Ingo Molnar , Andi Kleen Subject: Re: [PATCH] proc/kcore: Don't bounds check against address 0 Message-Id: <20180501144604.1cf872e7938bffc01a26349f@linux-foundation.org> In-Reply-To: <20180501201143.15121-1-labbott@redhat.com> References: <1039518799.26129578.1525185916272.JavaMail.zimbra@redhat.com> <20180501201143.15121-1-labbott@redhat.com> X-Mailer: Sylpheed 3.6.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 1 May 2018 13:11:43 -0700 Laura Abbott wrote: > The existing kcore code checks for bad addresses against > __va(0) with the assumption that this is the lowest address > on the system. This may not hold true on some systems (e.g. > arm64) and produce overflows and crashes. Switch to using > other functions to validate the address range. > > Tested-by: Dave Anderson > Signed-off-by: Laura Abbott > --- > I took your previous comments as a tested by, please let me know if that > was wrong. This should probably just go through -mm. I don't think this > is necessary for stable but I can request it later if necessary. I'm surprised. "overflows and crashes" sounds rather serious??