From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932580AbbKDJpB (ORCPT ); Wed, 4 Nov 2015 04:45:01 -0500 Received: from mx2.suse.de ([195.135.220.15]:50401 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932303AbbKDJo4 (ORCPT ); Wed, 4 Nov 2015 04:44:56 -0500 Date: Wed, 4 Nov 2015 10:44:55 +0100 (CET) From: Jiri Kosina X-X-Sender: jkosina@pobox.suse.cz To: Zhou Chengming cc: jpoimboe@redhat.com, sjenning@redhat.com, vojtech@suse.cz, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, guohanjun@huawei.com, huawei.libin@huawei.com, xiexiuqi@huawei.com, cbay@alwaysdata.com Subject: Re: [PATCH] livepatch: x86: bugfix about kASLR In-Reply-To: <1446629532-32111-1-git-send-email-zhouchengming1@huawei.com> Message-ID: References: <1446629532-32111-1-git-send-email-zhouchengming1@huawei.com> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) 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 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. > + /* 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, -- Jiri Kosina SUSE Labs