From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964850AbbKDKGI (ORCPT ); Wed, 4 Nov 2015 05:06:08 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:18363 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932205AbbKDKGF (ORCPT ); Wed, 4 Nov 2015 05:06:05 -0500 Message-ID: <5639D85C.5080703@huawei.com> Date: Wed, 4 Nov 2015 18:05:16 +0800 From: zhouchengming User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Jiri Kosina CC: , , , , , , , , Subject: Re: [PATCH] livepatch: x86: bugfix about kASLR References: <1446629532-32111-1-git-send-email-zhouchengming1@huawei.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.236.183] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090205.5639D87F.00A6,ss=1,re=0.000,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2011-05-27 18:58:46 X-Mirapoint-Loop-Id: 11361df5acf79e78f75648ec6d949f85 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/11/4 17:44, Jiri Kosina wrote: > On Wed, 4 Nov 2015, Zhou Chengming wrote: > >> When enable KASLR, func->old_addr will be set to zero >> and livepatch will find the right old address. >> But for reloc, livepatch just verify it using reloc->val >> (old addr from user), so verify failed and report >> "kernel mismatch" error. >> >> Reported-by: Cyril B. >> Signed-off-by: Zhou Chengming >> --- >> kernel/livepatch/core.c | 7 ++++++- >> 1 files changed, 6 insertions(+), 1 deletions(-) >> >> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c >> index 53196e2..c8885c6 100644 >> --- a/kernel/livepatch/core.c >> +++ b/kernel/livepatch/core.c >> @@ -311,7 +311,12 @@ static int klp_write_object_relocations(struct module *pmod, >> return -EINVAL; >> >> for (reloc = obj->relocs; reloc->name; reloc++) { >> - if (!klp_is_module(obj)) { >> + >> +#if defined(CONFIG_RANDOMIZE_BASE) > CONFIG_RANDOMIZE_BASE being enabled by itself doesn't directly imply that > kASLR has been actually really enabled during runtime. You need > to check kaslr_enabled() as well. Right. >> + /* KASLR is enabled, disregard old_addr from user */ >> + reloc->val = 0; > Is there a reason why to discard it completely? Adding kaslr_offset() > should give us the correct address, right? > > Thanks, > Yes, it's definitely better. Thanks