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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 5FAA2C4BA1C for ; Wed, 26 Feb 2020 16:55:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 35A322467F for ; Wed, 26 Feb 2020 16:55:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727932AbgBZQz0 (ORCPT ); Wed, 26 Feb 2020 11:55:26 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:58297 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727895AbgBZQzZ (ORCPT ); Wed, 26 Feb 2020 11:55:25 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1j6zxp-0002Dl-M2; Wed, 26 Feb 2020 17:55:13 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 4E7871C215D; Wed, 26 Feb 2020 17:55:13 +0100 (CET) Date: Wed, 26 Feb 2020 16:55:13 -0000 From: "tip-bot2 for Ard Biesheuvel" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: efi/urgent] efi/x86: Handle by-ref arguments covering multiple pages in mixed mode Cc: Ard Biesheuvel , Ingo Molnar , linux-efi@vger.kernel.org, Thomas Gleixner , x86 , LKML In-Reply-To: <20200221084849.26878-4-ardb@kernel.org> References: <20200221084849.26878-4-ardb@kernel.org> MIME-Version: 1.0 Message-ID: <158273611305.28353.13754847201520575034.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org The following commit has been merged into the efi/urgent branch of tip: Commit-ID: 8319e9d5ad98ffccd19f35664382c73cea216193 Gitweb: https://git.kernel.org/tip/8319e9d5ad98ffccd19f35664382c73cea216193 Author: Ard Biesheuvel AuthorDate: Fri, 21 Feb 2020 09:48:48 +01:00 Committer: Ingo Molnar CommitterDate: Wed, 26 Feb 2020 15:31:42 +01:00 efi/x86: Handle by-ref arguments covering multiple pages in mixed mode The mixed mode runtime wrappers are fragile when it comes to how the memory referred to by its pointer arguments are laid out in memory, due to the fact that it translates these addresses to physical addresses that the runtime services can dereference when running in 1:1 mode. Since vmalloc'ed pages (including the vmap'ed stack) are not contiguous in the physical address space, this scheme only works if the referenced memory objects do not cross page boundaries. Currently, the mixed mode runtime service wrappers require that all by-ref arguments that live in the vmalloc space have a size that is a power of 2, and are aligned to that same value. While this is a sensible way to construct an object that is guaranteed not to cross a page boundary, it is overly strict when it comes to checking whether a given object violates this requirement, as we can simply take the physical address of the first and the last byte, and verify that they point into the same physical page. When this check fails, we emit a WARN(), but then simply proceed with the call, which could cause data corruption if the next physical page belongs to a mapping that is entirely unrelated. Given that with vmap'ed stacks, this condition is much more likely to trigger, let's relax the condition a bit, but fail the runtime service call if it does trigger. Fixes: f6697df36bdf0bf7 ("x86/efi: Prevent mixed mode boot corruption with CONFIG_VMAP_STACK=y") Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Cc: linux-efi@vger.kernel.org Cc: Ingo Molnar Cc: Thomas Gleixner Link: https://lore.kernel.org/r/20200221084849.26878-4-ardb@kernel.org --- arch/x86/platform/efi/efi_64.c | 45 +++++++++++++++++++-------------- 1 file changed, 26 insertions(+), 19 deletions(-) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index ae39858..d19a2ed 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -180,7 +180,7 @@ void efi_sync_low_kernel_mappings(void) static inline phys_addr_t virt_to_phys_or_null_size(void *va, unsigned long size) { - bool bad_size; + phys_addr_t pa; if (!va) return 0; @@ -188,16 +188,13 @@ virt_to_phys_or_null_size(void *va, unsigned long size) if (virt_addr_valid(va)) return virt_to_phys(va); - /* - * A fully aligned variable on the stack is guaranteed not to - * cross a page bounary. Try to catch strings on the stack by - * checking that 'size' is a power of two. - */ - bad_size = size > PAGE_SIZE || !is_power_of_2(size); + pa = slow_virt_to_phys(va); - WARN_ON(!IS_ALIGNED((unsigned long)va, size) || bad_size); + /* check if the object crosses a page boundary */ + if (WARN_ON((pa ^ (pa + size - 1)) & PAGE_MASK)) + return 0; - return slow_virt_to_phys(va); + return pa; } #define virt_to_phys_or_null(addr) \ @@ -615,8 +612,11 @@ efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor, phys_attr = virt_to_phys_or_null(attr); phys_data = virt_to_phys_or_null_size(data, *data_size); - status = efi_thunk(get_variable, phys_name, phys_vendor, - phys_attr, phys_data_size, phys_data); + if (!phys_name || (data && !phys_data)) + status = EFI_INVALID_PARAMETER; + else + status = efi_thunk(get_variable, phys_name, phys_vendor, + phys_attr, phys_data_size, phys_data); spin_unlock_irqrestore(&efi_runtime_lock, flags); @@ -641,9 +641,11 @@ efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor, phys_vendor = virt_to_phys_or_null(vnd); phys_data = virt_to_phys_or_null_size(data, data_size); - /* If data_size is > sizeof(u32) we've got problems */ - status = efi_thunk(set_variable, phys_name, phys_vendor, - attr, data_size, phys_data); + if (!phys_name || !phys_data) + status = EFI_INVALID_PARAMETER; + else + status = efi_thunk(set_variable, phys_name, phys_vendor, + attr, data_size, phys_data); spin_unlock_irqrestore(&efi_runtime_lock, flags); @@ -670,9 +672,11 @@ efi_thunk_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, phys_vendor = virt_to_phys_or_null(vnd); phys_data = virt_to_phys_or_null_size(data, data_size); - /* If data_size is > sizeof(u32) we've got problems */ - status = efi_thunk(set_variable, phys_name, phys_vendor, - attr, data_size, phys_data); + if (!phys_name || !phys_data) + status = EFI_INVALID_PARAMETER; + else + status = efi_thunk(set_variable, phys_name, phys_vendor, + attr, data_size, phys_data); spin_unlock_irqrestore(&efi_runtime_lock, flags); @@ -698,8 +702,11 @@ efi_thunk_get_next_variable(unsigned long *name_size, phys_vendor = virt_to_phys_or_null(vnd); phys_name = virt_to_phys_or_null_size(name, *name_size); - status = efi_thunk(get_next_variable, phys_name_size, - phys_name, phys_vendor); + if (!phys_name) + status = EFI_INVALID_PARAMETER; + else + status = efi_thunk(get_next_variable, phys_name_size, + phys_name, phys_vendor); spin_unlock_irqrestore(&efi_runtime_lock, flags);