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=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 7EC04C3A5A0 for ; Tue, 20 Aug 2019 00:19:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4FBCD2087E for ; Tue, 20 Aug 2019 00:19:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="g1htn3p5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728704AbfHTAT1 (ORCPT ); Mon, 19 Aug 2019 20:19:27 -0400 Received: from mail-qk1-f202.google.com ([209.85.222.202]:54644 "EHLO mail-qk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729205AbfHTATX (ORCPT ); Mon, 19 Aug 2019 20:19:23 -0400 Received: by mail-qk1-f202.google.com with SMTP id x28so5215329qki.21 for ; Mon, 19 Aug 2019 17:19:23 -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=+olFNxFYhjL9QRL4ImBQxYfzLxvoDTRC2EU1toIBTB8=; b=g1htn3p5MZXFXzHIA+Jjt6jTrPQQXmo5akMJNxXZhfwpce3QyP067kNbJy/zfSbTxP cqz6lYhGVH0Y58/jTvOZi73Je+dj6hcnU1VPmFh5JWW26socuEY2ootWG3DEUR1iI5Nj FkuD5Sr2MnqIJJ0/mQ2m1R+Gatojxz/0YnCKFlSUhlohVO86a0EARley9S0ZUdIQjx2/ PHareqg3wUQzuEQVwba2lcWN6esQv5jG3FrggakTQ/4Pq46kBazhFsDcmiyM2nxDFwVX 7HJPcEoP4vJw5ivPgLu++46qCQuAEe782JNqba2Z2LlbukNPdEi26D4bMgjB2C4twbvo XJvQ== 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=+olFNxFYhjL9QRL4ImBQxYfzLxvoDTRC2EU1toIBTB8=; b=eZlYsNddS1tuIZYI2CBjej9ntMf4DwGlnSBTVqKdZU7HXIuMzi2L0D87LgVP8Vqof0 2LEznJmGFzM4w/m6zmXiQe8+DXVQH71O6WiB9wy5TFShQ8dd91RNyChrqWZaipQdZ4Hn OLBtxRCEx634n98DeTgJgDLC781DNIHQA8biKPEZV7hLSKkg87ZneicFqPnodW8Wt6kl OMEiwYYpRo9UHFNu8igR7ha3WzMd00mi3hOWmedQIkK8b7Kzv6O6T+5ZXiqRxJ4aD0qM ZsTl2XWoJgCkhT3fITyZ/jnpcVsGH8+8LAxUkwCjZECtwFJUc8SPeBHr+8ceMhO6/WMc beDA== X-Gm-Message-State: APjAAAVpzl3f20lMDoghqL2CWMkhXwC7YmPpXGbFaWIlfKcT+0EJ5ShT wOsmDcKVTLjCjDb8qYGbwHHvXEpVvAOTVqfGwcbK1A== X-Google-Smtp-Source: APXvYqyKVq6bwM7kYeFQvbD+BxIpXVpiuWJNkgMoBfKq9+4QIWBY0VIK8EebTXkq1faB4DrgMP8UwAK2DmoUx9lvKKRkxw== X-Received: by 2002:a05:620a:4c8:: with SMTP id 8mr21987278qks.366.1566260362547; Mon, 19 Aug 2019 17:19:22 -0700 (PDT) Date: Mon, 19 Aug 2019 17:18:04 -0700 In-Reply-To: <20190820001805.241928-1-matthewgarrett@google.com> Message-Id: <20190820001805.241928-29-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190820001805.241928-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.23.0.rc1.153.gdeed80330f-goog Subject: [PATCH V40 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 Signed-off-by: James Morris --- 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 4b7cf7bc0ded..5f98374f77f4 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -30,6 +30,7 @@ #include #include #include +#include #include @@ -241,6 +242,11 @@ 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 -- 2.23.0.rc1.153.gdeed80330f-goog