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=-6.8 required=3.0 tests=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 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 C3281C48BD5 for ; Tue, 25 Jun 2019 15:00:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F157213F2 for ; Tue, 25 Jun 2019 15:00:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="XEkdwu9t" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731968AbfFYPAg (ORCPT ); Tue, 25 Jun 2019 11:00:36 -0400 Received: from mail-io1-f68.google.com ([209.85.166.68]:45599 "EHLO mail-io1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731959AbfFYPAg (ORCPT ); Tue, 25 Jun 2019 11:00:36 -0400 Received: by mail-io1-f68.google.com with SMTP id e3so164381ioc.12 for ; Tue, 25 Jun 2019 08:00:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=WCu2izc+AwFs8dxkBWfG0kU/xQQY4HsLibUm2/EhQEg=; b=XEkdwu9tbyxynV2UESVQpvwU3iwK3hOE1k9Q1V76kobtha4OFJg8EuxOwyr9iFmFCF 03+IP8ze/+IkOWgqwTpYK3IA+caa2YfQYz/eo6KfpwPMDhq0+7/rvOJSrpLmt6w+CQny NEdRK0dC/Ou/b9ECjr3caBsF5fwJhkr+xfFWaaDRwrRWL3rhMeeWH8HFoBrAKmYGIkva h4nN/l3U6DtLZdNSOnQL9Ih7R4Vh9q25kWm87wwuDzJtxPiQd0g9nyeidql+/whr0yY8 hRSCFlzTYLEpYV2kxsIbsi+thmD6DyDRJf9PwCSIWPW0GUf18A1wZrVKYFPGX3EEcJNl GGvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=WCu2izc+AwFs8dxkBWfG0kU/xQQY4HsLibUm2/EhQEg=; b=JgsmHwIc3fVpkKzvYhsV5L7m1QlhgIo0J6vt4+hSykeeL5wLs8aS0tfreoXrZddrUY 2qOEx5BRK+UNrAhZJLuV3ANufJWVkJmItf4+tl2j2o5L/ZexFl/AY/uYn4E30XPR/xWT AOsCyrLYsWZjhp3ehPKocJRhLe5XbbA3NlDpyVy+SrnLdBlMRfoj8ErwNyTisuHspTjf t4X0g6xceQT9rNnGY1n8qi6SavTfyehBLJ281i5/xe3RtmsOVsPy/yfzY1xHIgjCZY0h UGPzJgupR9fF4L+w4D/R/FCMeROTwWcEhvo6nSlGleQx0fCCZ3wfOETtqT9SH/UOIufR I0nw== X-Gm-Message-State: APjAAAWkjLNIhiP1tQtCyqLNdkNfjgU8L0Rq6YrIVCJOqjgKlAyaFY2F xeRyI4teUs2HPhQCEXBXOBADkYeaXKsb1IKK8R81+A== X-Google-Smtp-Source: APXvYqzeVOugDrWRv5GZLuCebGXK5dE6WckDZUY2y3Mwk6wopB+mgprQm2ZWsgT4yJQvT/jz99cbIBKpq58fNj+5zo0= X-Received: by 2002:a02:c90d:: with SMTP id t13mr112928904jao.62.1561474835326; Tue, 25 Jun 2019 08:00:35 -0700 (PDT) MIME-Version: 1.0 References: <20190622000358.19895-1-matthewgarrett@google.com> <20190622000358.19895-29-matthewgarrett@google.com> In-Reply-To: <20190622000358.19895-29-matthewgarrett@google.com> From: Ard Biesheuvel Date: Tue, 25 Jun 2019 17:00:24 +0200 Message-ID: Subject: Re: [PATCH V34 28/29] efi: Restrict efivar_ssdt_load when the kernel is locked down To: Matthew Garrett Cc: James Morris , linux-security-module , Linux Kernel Mailing List , linux-api@vger.kernel.org, Matthew Garrett , linux-efi 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 On Sat, 22 Jun 2019 at 02:05, Matthew Garrett wrote: > > 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 > Cc: Ard Biesheuvel > Cc: linux-efi@vger.kernel.org Acked-by: Ard Biesheuvel > --- > 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 55b77c576c42..9f92a013ab27 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -31,6 +31,7 @@ > #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 > -- > 2.22.0.410.gd8fdbe21b5-goog >