From patchwork Wed Jun 12 17:08:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marius Hillenbrand X-Patchwork-Id: 10990413 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 627E41395 for ; Wed, 12 Jun 2019 17:10:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4BBE228A17 for ; Wed, 12 Jun 2019 17:10:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3FC0728A28; Wed, 12 Jun 2019 17:10:10 +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=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable 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 E452328A41 for ; Wed, 12 Jun 2019 17:10:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730771AbfFLRKG (ORCPT ); Wed, 12 Jun 2019 13:10:06 -0400 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:63229 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726384AbfFLRKF (ORCPT ); Wed, 12 Jun 2019 13:10:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazon201209; t=1560359405; x=1591895405; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=RGV2nXv0tDBodUuIHbEss/S4uQOCZyMq1lOqu82Edzk=; b=fUzZrGvA6Fc5l5xPT60CAit2NcoQyNcptxu+f3h6FWfQFqRjf3sJRRJ0 gmOawV7Nju6Yj2heEQBGIHtzbIry6rit8cIpHHoIfE70p1qYmtzIFKNGP 9uFAtDEaxwFh0qTKR47oggejyyGkxtYWZeOl7yXtEnE42e8bBh7HfqE6Q w=; X-IronPort-AV: E=Sophos;i="5.62,366,1554768000"; d="scan'208";a="400444646" Received: from iad6-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1d-9ec21598.us-east-1.amazon.com) ([10.124.125.6]) by smtp-border-fw-out-6001.iad6.amazon.com with ESMTP; 12 Jun 2019 17:10:03 +0000 Received: from ua08cfdeba6fe59dc80a8.ant.amazon.com (iad7-ws-svc-lb50-vlan3.amazon.com [10.0.93.214]) by email-inbound-relay-1d-9ec21598.us-east-1.amazon.com (Postfix) with ESMTPS id 43F06A258B; Wed, 12 Jun 2019 17:10:02 +0000 (UTC) Received: from ua08cfdeba6fe59dc80a8.ant.amazon.com (ua08cfdeba6fe59dc80a8.ant.amazon.com [127.0.0.1]) by ua08cfdeba6fe59dc80a8.ant.amazon.com (8.15.2/8.15.2/Debian-3) with ESMTP id x5CH9x1s017050; Wed, 12 Jun 2019 19:09:59 +0200 Received: (from mhillenb@localhost) by ua08cfdeba6fe59dc80a8.ant.amazon.com (8.15.2/8.15.2/Submit) id x5CH9xNm017043; Wed, 12 Jun 2019 19:09:59 +0200 From: Marius Hillenbrand To: kvm@vger.kernel.org Cc: Marius Hillenbrand , linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, Alexander Graf , David Woodhouse Subject: [RFC 01/10] x86/mm/kaslr: refactor to use enum indices for regions Date: Wed, 12 Jun 2019 19:08:26 +0200 Message-Id: <20190612170834.14855-2-mhillenb@amazon.de> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190612170834.14855-1-mhillenb@amazon.de> References: <20190612170834.14855-1-mhillenb@amazon.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The KASLR randomization code currently refers to specific regions, such as the vmalloc area, by literal indices into an array. When adding new regions, we have to be careful to also change all indices that may potentially change. Avoid that risk by introducing an enum used as indices. Signed-off-by: Marius Hillenbrand Cc: Alexander Graf Cc: David Woodhouse --- arch/x86/mm/kaslr.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c index 3f452ffed7e9..c455f1ffba29 100644 --- a/arch/x86/mm/kaslr.c +++ b/arch/x86/mm/kaslr.c @@ -41,6 +41,12 @@ */ static const unsigned long vaddr_end = CPU_ENTRY_AREA_BASE; +enum { + PHYSMAP, + VMALLOC, + VMMEMMAP, +}; + /* * Memory regions randomized by KASLR (except modules that use a separate logic * earlier during boot). The list is ordered based on virtual addresses. This @@ -50,9 +56,9 @@ static __initdata struct kaslr_memory_region { unsigned long *base; unsigned long size_tb; } kaslr_regions[] = { - { &page_offset_base, 0 }, - { &vmalloc_base, 0 }, - { &vmemmap_base, 1 }, + [PHYSMAP] = { &page_offset_base, 0 }, + [VMALLOC] = { &vmalloc_base, 0 }, + [VMMEMMAP] = { &vmemmap_base, 1 }, }; /* Get size in bytes used by the memory region */ @@ -94,20 +100,20 @@ void __init kernel_randomize_memory(void) if (!kaslr_memory_enabled()) return; - kaslr_regions[0].size_tb = 1 << (__PHYSICAL_MASK_SHIFT - TB_SHIFT); - kaslr_regions[1].size_tb = VMALLOC_SIZE_TB; + kaslr_regions[PHYSMAP].size_tb = 1 << (__PHYSICAL_MASK_SHIFT - TB_SHIFT); + kaslr_regions[VMALLOC].size_tb = VMALLOC_SIZE_TB; /* * Update Physical memory mapping to available and * add padding if needed (especially for memory hotplug support). */ - BUG_ON(kaslr_regions[0].base != &page_offset_base); + BUG_ON(kaslr_regions[PHYSMAP].base != &page_offset_base); memory_tb = DIV_ROUND_UP(max_pfn << PAGE_SHIFT, 1UL << TB_SHIFT) + CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING; /* Adapt phyiscal memory region size based on available memory */ - if (memory_tb < kaslr_regions[0].size_tb) - kaslr_regions[0].size_tb = memory_tb; + if (memory_tb < kaslr_regions[PHYSMAP].size_tb) + kaslr_regions[PHYSMAP].size_tb = memory_tb; /* Calculate entropy available between regions */ remain_entropy = vaddr_end - vaddr_start;