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,URIBL_BLOCKED, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 5B702C433FF for ; Wed, 31 Jul 2019 22:17:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E459206B8 for ; Wed, 31 Jul 2019 22:17:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NQeE8brz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731446AbfGaWRm (ORCPT ); Wed, 31 Jul 2019 18:17:42 -0400 Received: from mail-vs1-f73.google.com ([209.85.217.73]:44675 "EHLO mail-vs1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731430AbfGaWRj (ORCPT ); Wed, 31 Jul 2019 18:17:39 -0400 Received: by mail-vs1-f73.google.com with SMTP id j186so18230637vsc.11 for ; Wed, 31 Jul 2019 15:17:38 -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=BzJTfX0sYPsZSKyjJWnAiNewKfNmb8++vKsSknaZcxY=; b=NQeE8brzaM3nBKem2ZVyyY3FlEol8+CrHwKsZLyG2nOLqNXrqwU1ggJ6taMJBGtcvu u7ivnCOY/vCLH1PL1/ogOR1ufcUTaOZ5A/mx04CAwV3BoOuxIBirZiRs95dk3JRblihh tXPBxMpECDPUl9yY6d9SLCc2j/+TY7PF7+dohxG/zRAacI1a3PqRwnerhdX3/TNysAoS v/R6NSDtkIvFt4+d+hrBiGHwm3+8hQa3NyNj3mVZY9VVwj/L7gOlu1B21IDKaq5Gi8qX tOMgZItvzzSlRYr4GQVKc1U79UZPz8SKxqxaYhkJRhn4p2NfwVnpKyTpZK6Vvz1uJwiT QjVg== 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=BzJTfX0sYPsZSKyjJWnAiNewKfNmb8++vKsSknaZcxY=; b=kSgAF0g6ovWRssSQSD3YdfJ5Hh4wVbZzCn/FwzGp5PDlUIlfRsvhgQHuZn/Z2YL2UP zxQU0FLvZ+0zdh7e0bWPGBrDxEnPAoa3KR3XEcr4taTqwPFS+a/A2gcxSZ/0phjKiVN3 RVfzZUXcrNsfHnYmNCsBJTbmVFbTzB7P1hCmtW7MsW1ptyLLDrGkpzmm5SuT8dLZp8ii R5sitsnlap8OkmUBCs4djmMEPF2XkzAtKGYMyXdkU3mobTaQbrUnfmhew6L7MJqCjqw7 6bh4L1MflO9PPQhzYIyYytRRyQ9KuZQcKwaX56jrkX/oTQ+TG79K7tEbqy9zHaRmejbq S6Qw== X-Gm-Message-State: APjAAAU67NuSfiO9VyAdk4QcFWyBszaIgYCUvSJBZJZ+BN56Xhv8g5fQ KdnW8MmvSUCvlCAEzZmTkaWJYDeJrZszupY3rWG8QQ== X-Google-Smtp-Source: APXvYqxXL/N38PSOgMKwgKt2xZvaRoxQEDDLyN7w15v7c2XIakO5nBHL6rYO8tJ55Q7U2Z/pstfcpGH7UN4+XC4dCW0dhQ== X-Received: by 2002:a67:8907:: with SMTP id l7mr80628361vsd.194.1564611458042; Wed, 31 Jul 2019 15:17:38 -0700 (PDT) Date: Wed, 31 Jul 2019 15:16:16 -0700 In-Reply-To: <20190731221617.234725-1-matthewgarrett@google.com> Message-Id: <20190731221617.234725-29-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190731221617.234725-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.770.g0f2c4a37fd-goog Subject: [PATCH V37 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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 -- 2.22.0.770.g0f2c4a37fd-goog