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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71253C31E5B for ; Mon, 17 Jun 2019 21:35:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 455F12070B for ; Mon, 17 Jun 2019 21:35:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560807318; bh=WRt3hZwVhxYc1hGY5XlW7OH/gGDtHJG3c1BdxS3erHc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JT2tnIpv3h/i7a6Vc/braBKsMUDGwSLmFDgsR7fLYtoLasiw254IxN7DHisEFlpW/ kvfMlxuiSYyd0KJEprzGVQzLYdmqiizLVIqOTJkLsx6/K2zeWanWB95SZfLfV7t2Ci b6waUq1xNxXxpxypdyQV1K2Yq0VuXXr6fzVguLnM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729716AbfFQVX2 (ORCPT ); Mon, 17 Jun 2019 17:23:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:48574 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726723AbfFQVX1 (ORCPT ); Mon, 17 Jun 2019 17:23:27 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6110520657; Mon, 17 Jun 2019 21:23:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560806606; bh=WRt3hZwVhxYc1hGY5XlW7OH/gGDtHJG3c1BdxS3erHc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BCfCbjb99QFjwZbrzkRV8NYwNyxFgal4g8ds133Dn3L26bRunwua0gt/XsEF+yTt5 ADhno82q7/uosIgOg95LOSgu4ZEAn/rVGOxEzlgepfqyyhiOatKn+cHDkB38JuoDJ8 iJ9tTIuZMF6I/TnMcSat1u4IJdfkpXEDgVmkB9hE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Baoquan He , Borislav Petkov , Kees Cook , "Kirill A. Shutemov" , Andy Lutomirski , Dave Hansen , "H. Peter Anvin" , Ingo Molnar , kirill.shutemov@linux.intel.com, Peter Zijlstra , Thomas Gleixner , x86-ml Subject: [PATCH 5.1 110/115] x86/mm/KASLR: Compute the size of the vmemmap section properly Date: Mon, 17 Jun 2019 23:10:10 +0200 Message-Id: <20190617210805.524763038@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190617210759.929316339@linuxfoundation.org> References: <20190617210759.929316339@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Baoquan He commit 00e5a2bbcc31d5fea853f8daeba0f06c1c88c3ff upstream. The size of the vmemmap section is hardcoded to 1 TB to support the maximum amount of system RAM in 4-level paging mode - 64 TB. However, 1 TB is not enough for vmemmap in 5-level paging mode. Assuming the size of struct page is 64 Bytes, to support 4 PB system RAM in 5-level, 64 TB of vmemmap area is needed: 4 * 1000^5 PB / 4096 bytes page size * 64 bytes per page struct / 1000^4 TB = 62.5 TB. This hardcoding may cause vmemmap to corrupt the following cpu_entry_area section, if KASLR puts vmemmap very close to it and the actual vmemmap size is bigger than 1 TB. So calculate the actual size of the vmemmap region needed and then align it up to 1 TB boundary. In 4-level paging mode it is always 1 TB. In 5-level it's adjusted on demand. The current code reserves 0.5 PB for vmemmap on 5-level. With this change, the space can be saved and thus used to increase entropy for the randomization. [ bp: Spell out how the 64 TB needed for vmemmap is computed and massage commit message. ] Fixes: eedb92abb9bb ("x86/mm: Make virtual memory layout dynamic for CONFIG_X86_5LEVEL=y") Signed-off-by: Baoquan He Signed-off-by: Borislav Petkov Reviewed-by: Kees Cook Acked-by: Kirill A. Shutemov Cc: Andy Lutomirski Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: kirill.shutemov@linux.intel.com Cc: Peter Zijlstra Cc: stable Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20190523025744.3756-1-bhe@redhat.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/kaslr.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/arch/x86/mm/kaslr.c +++ b/arch/x86/mm/kaslr.c @@ -52,7 +52,7 @@ static __initdata struct kaslr_memory_re } kaslr_regions[] = { { &page_offset_base, 0 }, { &vmalloc_base, 0 }, - { &vmemmap_base, 1 }, + { &vmemmap_base, 0 }, }; /* Get size in bytes used by the memory region */ @@ -78,6 +78,7 @@ void __init kernel_randomize_memory(void unsigned long rand, memory_tb; struct rnd_state rand_state; unsigned long remain_entropy; + unsigned long vmemmap_size; vaddr_start = pgtable_l5_enabled() ? __PAGE_OFFSET_BASE_L5 : __PAGE_OFFSET_BASE_L4; vaddr = vaddr_start; @@ -109,6 +110,14 @@ void __init kernel_randomize_memory(void if (memory_tb < kaslr_regions[0].size_tb) kaslr_regions[0].size_tb = memory_tb; + /* + * Calculate the vmemmap region size in TBs, aligned to a TB + * boundary. + */ + vmemmap_size = (kaslr_regions[0].size_tb << (TB_SHIFT - PAGE_SHIFT)) * + sizeof(struct page); + kaslr_regions[2].size_tb = DIV_ROUND_UP(vmemmap_size, 1UL << TB_SHIFT); + /* Calculate entropy available between regions */ remain_entropy = vaddr_end - vaddr_start; for (i = 0; i < ARRAY_SIZE(kaslr_regions); i++)