From patchwork Fri Jun 26 15:58:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 11627929 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2E57D1392 for ; Fri, 26 Jun 2020 16:01:29 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 07D8B2075D for ; Fri, 26 Jun 2020 16:01:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="LqIhjK/r"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="KvkqltL7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 07D8B2075D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=oOpsRdBzzJkYUoI9U3BYKHT955dtaHhCu+qvJTZsYDQ=; b=LqIhjK/rBbvOSTKakiuOZ+cLG gqN+hDLospZyEofyVwfGNmif+Td5grCUsC4dPA7ytrFo/J2Jvt5jtTa6jJGHJr2phtFYuoggrxLCV ZSLt96j3XRgVRPy0IMynfvuR7nVqWVMo7g1MKqLZCVlwuDhfBNsXSOc0ej0eIiYSH/qxUafPYM8/C IMCbfq37zotph36J9crdWiIeN9FKA7vXHoeNBLz42AwDf9Y6juNAJB7rYGo0yvdDd0qXDJer9glSq OEY3ya7mXK8E0qqffSQ9D7ALqJQN1kjZQA60L3D5pI1t+aoedPu3nrK1zfcIsGFWdqupv0Th+f+mP SpfOOIPww==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1joqki-0006RI-2C; Fri, 26 Jun 2020 15:58:56 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1joqkV-0006Oj-Hv for linux-arm-kernel@lists.infradead.org; Fri, 26 Jun 2020 15:58:47 +0000 Received: from dogfood.home (lfbn-nic-1-188-42.w2-15.abo.wanadoo.fr [2.15.37.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 44682207FC; Fri, 26 Jun 2020 15:58:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593187123; bh=CLa/KzjkFuVB29ckXD65Yi/MPGSAfUM7uGj3uLRMd8c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KvkqltL7W8QSPKTPhvffxK28GoCuvQLjCChN2Ds1Eul/Ijdz/A4oA+ajy5pKuK7Y8 94WMZjajjI56YrQyBi5rSRaIHerNWXXrIqyvkRgXalg3TIe97DBCQy1h6HDSOvm81N VK9Lnps++4YE0cPVnQn+7mDc69oGPUt/SuJo6i/s= From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 1/2] arm64/acpi: disallow AML memory opregions to access kernel memory Date: Fri, 26 Jun 2020 17:58:31 +0200 Message-Id: <20200626155832.2323789-2-ardb@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200626155832.2323789-1-ardb@kernel.org> References: <20200626155832.2323789-1-ardb@kernel.org> MIME-Version: 1.0 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -5.2 (-----) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-5.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Jason A . Donenfeld" , lorenzo.pieralisi@arm.com, kernel-hardening@lists.openwall.com, catalin.marinas@arm.com, linux-acpi@vger.kernel.org, sudeep.holla@arm.com, will@kernel.org, Ard Biesheuvel Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org AML uses SystemMemory opregions to allow AML handlers to access MMIO registers of, e.g., GPIO controllers, or access reserved regions of memory that are owned by the firmware. Currently, we also allow AML access to memory that is owned by the kernel and mapped via the linear region, which does not seem to be supported by a valid use case, and exposes the kernel's internal state to AML methods that may be buggy and exploitable. On arm64, ACPI support requires booting in EFI mode, and so we can cross reference the requested region against the EFI memory map, rather than just do a minimal check on the first page. So let's only permit regions to be remapped by the ACPI core if - they don't appear in the EFI memory map at all (which is the case for most MMIO), or - they are covered by a single region in the EFI memory map, which is not of a type that describes memory that is given to the kernel at boot. Reported-by: Jason A. Donenfeld Signed-off-by: Ard Biesheuvel Tested-by: Jonathan Cameron Reviewed-by: Jonathan Cameron --- arch/arm64/include/asm/acpi.h | 15 +---- arch/arm64/kernel/acpi.c | 66 ++++++++++++++++++++ 2 files changed, 67 insertions(+), 14 deletions(-) diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index a45366c3909b..bd68e1b7f29f 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -47,20 +47,7 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr); /* ACPI table mapping after acpi_permanent_mmap is set */ -static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys, - acpi_size size) -{ - /* For normal memory we already have a cacheable mapping. */ - if (memblock_is_map_memory(phys)) - return (void __iomem *)__phys_to_virt(phys); - - /* - * We should still honor the memory's attribute here because - * crash dump kernel possibly excludes some ACPI (reclaim) - * regions from memblock list. - */ - return __ioremap(phys, size, __acpi_get_mem_attribute(phys)); -} +void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size); #define acpi_os_ioremap acpi_os_ioremap typedef u64 phys_cpuid_t; diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index a7586a4db142..01b861e225b0 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -261,6 +261,72 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr) return __pgprot(PROT_DEVICE_nGnRnE); } +void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size) +{ + efi_memory_desc_t *md, *region = NULL; + pgprot_t prot; + + if (WARN_ON_ONCE(!efi_enabled(EFI_MEMMAP))) + return NULL; + + for_each_efi_memory_desc(md) { + u64 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT); + + if (phys < md->phys_addr || phys >= end) + continue; + + if (phys + size > end) { + pr_warn(FW_BUG "requested region covers multiple EFI memory regions\n"); + return NULL; + } + region = md; + break; + } + + /* + * It is fine for AML to remap regions that are not represented in the + * EFI memory map at all, as it only describes normal memory, and MMIO + * regions that require a virtual mapping to make them accessible to + * the EFI runtime services. + */ + prot = __pgprot(PROT_DEVICE_nGnRnE); + if (region) { + switch (region->type) { + case EFI_LOADER_CODE: + case EFI_LOADER_DATA: + case EFI_BOOT_SERVICES_CODE: + case EFI_BOOT_SERVICES_DATA: + case EFI_CONVENTIONAL_MEMORY: + case EFI_PERSISTENT_MEMORY: + pr_warn(FW_BUG "requested region covers kernel memory @ %pa\n", &phys); + return NULL; + + case EFI_ACPI_RECLAIM_MEMORY: + /* + * ACPI reclaim memory is used to pass firmware tables + * and other data that is intended for consumption by + * the OS only, which may decide it wants to reclaim + * that memory and use it for something else. We never + * do that, but we usually add it to the linear map + * anyway, in which case we should use the existing + * mapping. + */ + if (memblock_is_map_memory(phys)) + return (void __iomem *)__phys_to_virt(phys); + /* fall through */ + + default: + if (region->attribute & EFI_MEMORY_WB) + prot = PAGE_KERNEL; + else if (region->attribute & EFI_MEMORY_WT) + prot = __pgprot(PROT_NORMAL_WT); + else if (region->attribute & EFI_MEMORY_WC) + prot = __pgprot(PROT_NORMAL_NC); + } + } + return __ioremap(phys, size, prot); +} + /* * Claim Synchronous External Aborts as a firmware first notification. *