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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 CF849C7618F for ; Mon, 15 Jul 2019 20:01:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9D2220659 for ; Mon, 15 Jul 2019 20:01:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SGpuCm9n" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731494AbfGOUBK (ORCPT ); Mon, 15 Jul 2019 16:01:10 -0400 Received: from mail-pl1-f201.google.com ([209.85.214.201]:43284 "EHLO mail-pl1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732768AbfGOUBI (ORCPT ); Mon, 15 Jul 2019 16:01:08 -0400 Received: by mail-pl1-f201.google.com with SMTP id t2so8819646plo.10 for ; Mon, 15 Jul 2019 13:01:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=1gkPgS/LUQWYTDhNcm4n5VtrDpueDO81OkRBGTKoxwg=; b=SGpuCm9nyv32QRgah8+1J8biiXF/tNR9HQ4GFBCBrRmNuWoaPEMCoMeG8CznrJ2xBC zkbDMbcYm8YcsYwmLzYCmSKjnsTMSvkKRRECL0tqQ36b9oNCLd5cuBcoa4BpCMdF21Fu O2tmCsQco516iIqUSW/mBRVF6fBtQAPjVYpsnS6G2E/HLyeMh1D0p0TkTpbvhIPBXbtS qtbaAbxFrni0pU2z0i41Fjy8ygJksGW51zsL1JC0ZC9Y3KF+G5b/rSrWYgjlPNfyEXRH GI0wIh/cCu2IgLJwz+vjTQ1V+oJarCXW6xl6K2cpPDlePYHuZsHrVGZ78+B3jX0whKqm o3xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=1gkPgS/LUQWYTDhNcm4n5VtrDpueDO81OkRBGTKoxwg=; b=dqc9hhY6YamL+YzPWt/4qQrL/aOQc+aNUavwTEEzjovx8HO6CFUap17/lZdVQZ4cyi z4pI5DaIiA6ZSKufu3+1uPUTubobevcuPZVjAilWfYserYhPXxpdDu1XxmJZWNw/3qXH VX8rWykYrASv/edPiG389ozTdgtZ422yE2R51s3ppURcWQzYU2J40WM6UbHX5+HrN9MJ Fqjz/pz40fBkn/sJ8kL8KtuONlk7Va0ZyCk5bC/RVPmN4kAHQidT+w7+nWictp/KlgpK /fcMBV0ZkMUeSsXpAicF0cDx1iYKxJ9lcEaFBH5+fpGmChEZXWnpatN45VnF4aW20G9H MBUQ== X-Gm-Message-State: APjAAAVQZaqXSJY01776hYVA7SbCTewebt6mG+UrvEa2JMHCuKcizsCh hT2nOjO+zGcXpT/gnWZ2Stdx5l/fG6MlXMCA39wUTg== X-Google-Smtp-Source: APXvYqx8IB42RsjuQvqr21hPpPSRXnXopU3sD+HW/qRD9CSWBN6XHwG27W8+mPAUWW4oj0dcn2icPxBiU0iXrQYpoIx1NQ== X-Received: by 2002:a63:7e1d:: with SMTP id z29mr28729222pgc.346.1563220867059; Mon, 15 Jul 2019 13:01:07 -0700 (PDT) Date: Mon, 15 Jul 2019 12:59:45 -0700 In-Reply-To: <20190715195946.223443-1-matthewgarrett@google.com> Message-Id: <20190715195946.223443-29-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190715195946.223443-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.510.g264f2c817a-goog Subject: [PATCH V35 28/29] efi: Restrict efivar_ssdt_load when the kernel is locked down From: Matthew Garrett To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Matthew Garrett , Matthew Garrett , Ard Biesheuvel , Kees Cook , linux-efi@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org efivar_ssdt_load allows the kernel to import arbitrary ACPI code from an EFI variable, which gives arbitrary code execution in ring 0. Prevent that when the kernel is locked down. Signed-off-by: Matthew Garrett Acked-by: Ard Biesheuvel Reviewed-by: Kees Cook Cc: Ard Biesheuvel Cc: linux-efi@vger.kernel.org --- drivers/firmware/efi/efi.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index ad3b1f4866b3..776f479e5499 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -30,6 +30,7 @@ #include #include #include +#include #include @@ -242,6 +243,11 @@ static void generic_ops_unregister(void) static char efivar_ssdt[EFIVAR_SSDT_NAME_MAX] __initdata; static int __init efivar_ssdt_setup(char *str) { + int ret = security_locked_down(LOCKDOWN_ACPI_TABLES); + + if (ret) + return ret; + if (strlen(str) < sizeof(efivar_ssdt)) memcpy(efivar_ssdt, str, strlen(str)); else -- 2.22.0.510.g264f2c817a-goog