From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1FC18C4332F for ; Mon, 23 May 2022 11:48:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234980AbiEWLsj (ORCPT ); Mon, 23 May 2022 07:48:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234914AbiEWLsi (ORCPT ); Mon, 23 May 2022 07:48:38 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B71150E29; Mon, 23 May 2022 04:48:37 -0700 (PDT) Received: from dggpemm500021.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4L6FtM0ZgVzfZNG; Mon, 23 May 2022 19:47:07 +0800 (CST) Received: from dggpemm500014.china.huawei.com (7.185.36.153) by dggpemm500021.china.huawei.com (7.185.36.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 23 May 2022 19:48:35 +0800 Received: from [10.174.178.120] (10.174.178.120) by dggpemm500014.china.huawei.com (7.185.36.153) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 23 May 2022 19:48:33 +0800 Message-ID: <2a8cc751-dd72-6fe7-9a33-d6f24769f57d@huawei.com> Date: Mon, 23 May 2022 19:48:33 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH 0/2] Add support to relocate kernel image to mirrored region To: CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , References: <20220419070150.254377-1-mawupeng1@huawei.com> <7058b8d8-c0cb-108e-0db9-2fdf5fb154cf@huawei.com> From: mawupeng In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.178.120] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500014.china.huawei.com (7.185.36.153) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org 在 2022/5/20 14:52, Ard Biesheuvel 写道: > On Fri, 20 May 2022 at 08:52, Ard Biesheuvel wrote: >> >> On Thu, 19 May 2022 at 13:09, mawupeng wrote: >>> >>> >>> >>> 在 2022/5/7 17:28, mawupeng 写道: >>>> >>>> >>>> 在 2022/5/3 17:58, Ard Biesheuvel 写道: >>>>> On Tue, 19 Apr 2022 at 08:43, Wupeng Ma wrote: >>>>>> >>>>>> From: Ma Wupeng >>>>>> >>>>>> Now system image will perfer to be located to mirrored regions both KASLR >>>>>> on and off. >>>>>> >>>>> >>>>> Hello Ma Wupeng, >>>>> >>>>> I wonder if we could simplify this as follows: >>>>> - ignore the non-KASLR case for now, and rely on the bootloader > load the image into mirrored memory if it exists; >>>> >>>> In grub, memory for static image is allocated via the following path: >>>> >>>> grub_cmd_linux >>>> kernel = grub_malloc(filelen) >>>> kernel_alloc_addr = grub_efi_allocate_any_pages (kernel_alloc_pages) >>>> grub_memcpy (kernel_addr, kernel, grub_min(filelen, kernel_size)) >>>> grub_loader_set (grub_linux_boot, grub_linux_unload, 0) >>>> >>>> Can we get memory from mirrored region by the following steps: >>>> 1. get memory map by calling grub_efi_get_memory_map() >>>> 2. iter all memory map to find a suitable mirrored memory area >>>> 3. locate kernel image to this area >>>> >>>> So, if kaslr is not enabled >>>> - grub will load kernel into mirrored region >>>> else >>>> - arm64-stub.c will relocate kernel image to mirrored region >>>> >>>> Is this feasible? >>> >>> Is this a feasible proposal to relocate the static kernel image itself >>> into more reliable memory? >>> >> >> I'm not sure, it all depends on the firmware. >> >> When GRUB calls LoadImage(), the firmware will reallocate the image >> and unpack it there. So it is really the firmware's job to ensure that >> the image is loaded into a suitable location. >> >> I have some code here that implements a EFI based decompressor, and >> which loads the kernel image into mirrored memory if it exists, >> without the need to move it again. It could trivially be modified to >> deal with non-randomized loads as well. >> > > Code is here > https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/log/?h=efi-decompressor-v2 I will test this later. Thanks. > .