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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 A86ADC35640 for ; Fri, 21 Feb 2020 08:49:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7EA7520722 for ; Fri, 21 Feb 2020 08:49:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582274967; bh=HgwKMUg7AzFdprudduJfFZZhALobPBBE0qFbG220VFc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FU/VxpGXZGBd7KIM6sFK6cbeGSys5vubveg5WFZsuk3Zw04G3RTnpVytgYcJColpP MAb5ZhBuJEWSxi2p1ODAYbqj25XS8NSXW2py3oFunhOtR7k5z+6Pv6njGVRm5YrsY8 cGFrUDU2kxnpKTWigr6oECjZw69bSi/DzVaW28lI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387849AbgBUIt0 (ORCPT ); Fri, 21 Feb 2020 03:49:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:58074 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728837AbgBUItJ (ORCPT ); Fri, 21 Feb 2020 03:49:09 -0500 Received: from e123331-lin.home (amontpellier-657-1-18-247.w109-210.abo.wanadoo.fr [109.210.65.247]) (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 20E822073A; Fri, 21 Feb 2020 08:49:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582274948; bh=HgwKMUg7AzFdprudduJfFZZhALobPBBE0qFbG220VFc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PkeqJZiV3Sy+obWiFVhV/jF3H8zqAGhFN8Rqv1xZiNapNOs3bPsq/E8xEWSSc7BMo BgF0HL4qoTTSWttmJhkEuHWyzCt6FRgGYGTMUsel+l6LakdpcQ58Q+ulaG+xoyMtAI qychDX5r9Pud/70zi3bf+YZdaPhYWR7i+wSCqdo8= From: Ard Biesheuvel To: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org Subject: [PATCH 1/4] efi/x86: align GUIDs to their size in the mixed mode runtime wrapper Date: Fri, 21 Feb 2020 09:48:46 +0100 Message-Id: <20200221084849.26878-2-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200221084849.26878-1-ardb@kernel.org> References: <20200221084849.26878-1-ardb@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hans reports that his mixed mode systems running v5.6-rc1 kernels hit the WARN_ON() in virt_to_phys_or_null_size(), caused by the fact that efi_guid_t objects on the vmap'ed stack happen to be misaligned with respect to their sizes. As a quick (i.e., backportable) fix, copy GUID pointer arguments to the local stack into a buffer that is naturally aligned to its size, so that it is guaranteed to cover only one physical page. Note that on x86, we cannot rely on the stack pointer being aligned the way the compiler expects, so we need to allocate an 8-byte aligned buffer of sufficient size, and copy the GUID into that buffer at an offset that is aligned to 16 bytes. Fixes: f6697df36bdf0bf7 ("x86/efi: Prevent mixed mode boot corruption with CONFIG_VMAP_STACK=y") Reported-by: Hans de Goede Tested-by: Hans de Goede Signed-off-by: Ard Biesheuvel --- arch/x86/platform/efi/efi_64.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index fa8506e76bbe..543edfdcd1b9 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -658,6 +658,8 @@ static efi_status_t efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor, u32 *attr, unsigned long *data_size, void *data) { + u8 buf[24] __aligned(8); + efi_guid_t *vnd = PTR_ALIGN((efi_guid_t *)buf, sizeof(*vnd)); efi_status_t status; u32 phys_name, phys_vendor, phys_attr; u32 phys_data_size, phys_data; @@ -665,8 +667,10 @@ efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor, spin_lock_irqsave(&efi_runtime_lock, flags); + *vnd = *vendor; + phys_data_size = virt_to_phys_or_null(data_size); - phys_vendor = virt_to_phys_or_null(vendor); + phys_vendor = virt_to_phys_or_null(vnd); phys_name = virt_to_phys_or_null_size(name, efi_name_size(name)); phys_attr = virt_to_phys_or_null(attr); phys_data = virt_to_phys_or_null_size(data, *data_size); @@ -683,14 +687,18 @@ static efi_status_t efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor, u32 attr, unsigned long data_size, void *data) { + u8 buf[24] __aligned(8); + efi_guid_t *vnd = PTR_ALIGN((efi_guid_t *)buf, sizeof(*vnd)); u32 phys_name, phys_vendor, phys_data; efi_status_t status; unsigned long flags; spin_lock_irqsave(&efi_runtime_lock, flags); + *vnd = *vendor; + phys_name = virt_to_phys_or_null_size(name, efi_name_size(name)); - phys_vendor = virt_to_phys_or_null(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 */ @@ -707,6 +715,8 @@ efi_thunk_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, u32 attr, unsigned long data_size, void *data) { + u8 buf[24] __aligned(8); + efi_guid_t *vnd = PTR_ALIGN((efi_guid_t *)buf, sizeof(*vnd)); u32 phys_name, phys_vendor, phys_data; efi_status_t status; unsigned long flags; @@ -714,8 +724,10 @@ efi_thunk_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, if (!spin_trylock_irqsave(&efi_runtime_lock, flags)) return EFI_NOT_READY; + *vnd = *vendor; + phys_name = virt_to_phys_or_null_size(name, efi_name_size(name)); - phys_vendor = virt_to_phys_or_null(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 */ @@ -732,14 +744,18 @@ efi_thunk_get_next_variable(unsigned long *name_size, efi_char16_t *name, efi_guid_t *vendor) { + u8 buf[24] __aligned(8); + efi_guid_t *vnd = PTR_ALIGN((efi_guid_t *)buf, sizeof(*vnd)); efi_status_t status; u32 phys_name_size, phys_name, phys_vendor; unsigned long flags; spin_lock_irqsave(&efi_runtime_lock, flags); + *vnd = *vendor; + phys_name_size = virt_to_phys_or_null(name_size); - phys_vendor = virt_to_phys_or_null(vendor); + 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, @@ -747,6 +763,7 @@ efi_thunk_get_next_variable(unsigned long *name_size, spin_unlock_irqrestore(&efi_runtime_lock, flags); + *vendor = *vnd; return status; } -- 2.17.1