From patchwork Wed Oct 10 08:41:16 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Fan X-Patchwork-Id: 10634191 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 254B75CAF for ; Wed, 10 Oct 2018 08:42:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C0E9F29596 for ; Wed, 10 Oct 2018 08:42:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B4EAF2959A; Wed, 10 Oct 2018 08:42:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 33C0429596 for ; Wed, 10 Oct 2018 08:42:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727261AbeJJQC5 (ORCPT ); Wed, 10 Oct 2018 12:02:57 -0400 Received: from mail.cn.fujitsu.com ([183.91.158.132]:44081 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726636AbeJJQC4 (ORCPT ); Wed, 10 Oct 2018 12:02:56 -0400 X-IronPort-AV: E=Sophos;i="5.43,368,1503331200"; d="scan'208";a="45870136" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 10 Oct 2018 16:41:44 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (unknown [10.167.33.80]) by cn.fujitsu.com (Postfix) with ESMTP id 1037F4B6ED40; Wed, 10 Oct 2018 16:41:41 +0800 (CST) Received: from localhost.localdomain (10.167.225.56) by G08CNEXCHPEKD01.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.408.0; Wed, 10 Oct 2018 16:41:46 +0800 From: Chao Fan To: , , , , , , , , CC: , , , , Subject: [PATCH v8 0/3] x86/boot/KASLR: Parse ACPI table and limit kaslr in immovable memory Date: Wed, 10 Oct 2018 16:41:16 +0800 Message-ID: <20181010084119.17539-1-fanc.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.167.225.56] X-yoursite-MailScanner-ID: 1037F4B6ED40.AB399 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: fanc.fnst@cn.fujitsu.com Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP ***Background: People reported that kaslr may randomly chooses some positions which are located in movable memory regions. This will break memory hotplug feature and make the movable memory chosen by KASLR can't be removed. ***Solutions: There should be a method to limit kaslr to choosing immovable memory regions, so there are 2 solutions: 1) Add a kernel parameter to specify the memory regions. 2) Get the information of memory hot-remove, then kaslr will know the right regions. In method 2, information about memory hot-remove is in ACPI tables, which will be parsed after start_kernel(), kaslr can't get the information. In method 1, users should know the regions address and specify in kernel parameter. In the earliest time, I tried to dig ACPI tabls to solve this problem. But I didn't splite the code in 'compressed/' and ACPI code, so the patch is hard to follow so refused by community. Somebody suggest to add a kernel parameter to specify the immovable memory so that limit kaslr in these regions. Then I make a new patchset. After several versions, Ingo gave a suggestion: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1634024.html Follow Ingo's suggestion, imitate the ACPI code to parse the acpi tables, so that the kaslr can get necessary memory information in ACPI tables. I think ACPI code is an independent part, so copy the codes and functions to 'compressed/' directory, so that kaslr won't influence the initialization of ACPI. PATCH 1/3 Add acpitb.c to provide functions to parse ACPI code. PATCH 2/3 If CONFIG_MEMORY_HOTREMOVE enabled, walk all nodes and store the information of immovable memory regions. PATCH 3/3 According to the immovable memory regions, filter the immovable regions which KASLR can choose. ***Test results: - I did a very simple test, and it can get the memory information in bios and efi KVM guest machine, and put it by early printk. But no more tests, so it's with RFC tag. v1->v2: - Simplify some code. Follow Baoquan He's suggestion: - Reuse the head file of acpi code. v2->v3: - Test in more conditions, so remove the 'RFC' tag. - Change some comments. v3->v4: Follow Thomas Gleixner's suggetsion: - Put the whole efi related function into #define CONFIG_EFI and return false in the other stub. - Simplify two functions in head file. v4->v5: Follow Dou Liyang's suggestion: - Add more comments about some functions based on kernel code. - Change some typo in comments. - Clean useless variable. - Add check for the boundary of array. - Add check for 'movable_node' parameter v5->v6: Follow Baoquan He's suggestion: - Change some log. - Add the check for acpi_rsdp - Change some code logical to make code clear v6->v7: Follow Rafael's suggestion: - Add more comments and patch log. Follow test robot's suggestion: - Add "static" tag for function v7-v8: Follow Kees Cook's suggestion: - Use mem_overlaps() to check memory region. - Use #ifdef in the definition of function. Any comments will be welcome. Chao Fan (3): x86/boot: Add acpitb.c to parse acpi tables x86/boot/KASLR: Walk srat tables to filter immovable memory x86/boot/KASLR: Limit kaslr to choosing the immovable memory arch/x86/boot/compressed/Makefile | 2 + arch/x86/boot/compressed/acpitb.c | 405 ++++++++++++++++++++++++++++++ arch/x86/boot/compressed/kaslr.c | 75 +++++- arch/x86/boot/compressed/misc.h | 8 + 4 files changed, 479 insertions(+), 11 deletions(-) create mode 100644 arch/x86/boot/compressed/acpitb.c Signed-off-by: Masayoshi Mizuma