Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752163AbbHQD1K (ORCPT ); Sun, 16 Aug 2015 23:27:10 -0400 Received: from mail-pa0-f52.google.com ([209.85.220.52]:35401 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752027AbbHQD1J convert rfc822-to-8bit (ORCPT ); Sun, 16 Aug 2015 23:27:09 -0400 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) Subject: Re: [x86] copy_from{to}_user question From: yalin wang In-Reply-To: <20150813164302.GA15881@nazgul.tnic> Date: Mon, 17 Aug 2015 11:27:01 +0800 Cc: Thomas Gleixner , mingo@redhat.com, hpa@zytor.com, x86@kernel.org, open list , Will Deacon Content-Transfer-Encoding: 8BIT Message-Id: <6ABF6137-251E-47EF-B824-AC77C9C9AB24@gmail.com> References: <7FD389F5-C677-4439-8082-EB0CAE2814F6@gmail.com> <20150812100738.GA14020@nazgul.tnic> <9232AF8E-87A3-40B2-852A-D07889F9E1B4@gmail.com> <20150813164302.GA15881@nazgul.tnic> To: Borislav Petkov X-Mailer: Apple Mail (2.2098) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1059 Lines: 26 > On Aug 14, 2015, at 00:43, Borislav Petkov wrote: > > On Thu, Aug 13, 2015 at 06:04:54PM +0800, yalin wang wrote: >> we store type into one fix register, for example r12 , >> then in fix up code, we can know the exception is caused by copy_from >> copy_to or copy_in user function by check r12 value(0 , 1 ,2 value), then if >> it is copy_from, we only allow read fault, if the exception is write fault, panic() . >> >> the same rules also apply to copy_to / copy_in function . >> >> is it possible to change it like this ? > > ... and we'll do all that jumping through hoops to fix what actual, > real-life problem exactly? i just want the x86 copy_from{to,in}_user() function have the same behaviour as other platforms. and can disclose potential BUGs in kernel, if do like this. Thanks. -- 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/