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=DKIMWL_WL_HIGH,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=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 C11C4C3404C for ; Wed, 19 Feb 2020 00:59:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 96D1C2173E for ; Wed, 19 Feb 2020 00:59:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="IzhUosfr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727476AbgBSA67 (ORCPT ); Tue, 18 Feb 2020 19:58:59 -0500 Received: from mail-pl1-f194.google.com ([209.85.214.194]:40420 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726482AbgBSA66 (ORCPT ); Tue, 18 Feb 2020 19:58:58 -0500 Received: by mail-pl1-f194.google.com with SMTP id y1so8808611plp.7 for ; Tue, 18 Feb 2020 16:58:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=gnHrGjs2d4rz7O5tZjdzLtL+/TxZSgxldIF3J/GkKZs=; b=IzhUosfrcEGWqNX3mEcMBIr1zOOchilV9ewuFD+HoG5ciFAxqXbB4J+beO2BpkVdd2 SpEpavUmfa3Uu83TMZyvYqjzM1rYC38XzZ6PgxBVtweceDQ65TXzBQcjSOeXX0zJL559 DAcpGs9S0QzkDBHDXRYSuTfPTPAw54Oj19kC8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=gnHrGjs2d4rz7O5tZjdzLtL+/TxZSgxldIF3J/GkKZs=; b=RaQ9jMwkCVvQAUMWcLTxKMR2GeWgft/ne/T+FBm9X5PyQNBsRA4lM5kg84aFnghypS TfPY5jbHTdlpZFgSKqRMmyr4vIeJoXjopbGIdt9bDEfhbVPKmwZyYvHI3+QfPraEezgR 0G41YiAlUlELnGXyYtZxUeJY8dCAo20L+iRf2VGJVeA4D3Us33G75tzrrt646EknCAHM IChbW3Ny8iIaZk1yHxiNueD/j5iaXAOcIVCTSAqJRPzjTeY7JSdQ01wB0Z3QzwHG3NI0 z7PH+zx1z5aYkc0i20kOBgAxV7F36PLrpth5gWzAkObBPP8a0Eq+MkNv1rlYfl28KXY0 TH4Q== X-Gm-Message-State: APjAAAW4Dgipzh5qWYYVN2pdbgQzXFYCe+gV5XxJqPYgZw87FI1Mxr/R 2QucJMhdwAyT1aScNpueh5Hi1w== X-Google-Smtp-Source: APXvYqyyUVqi0udPEq0kk+xXnOiXAZrDL6nmRuPiWdSBtQVB+Zr5mfeTFPLXXkm6NSzwKNuLtifp4A== X-Received: by 2002:a17:902:7244:: with SMTP id c4mr21514780pll.49.1582073937923; Tue, 18 Feb 2020 16:58:57 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m18sm155133pgd.39.2020.02.18.16.58.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Feb 2020 16:58:57 -0800 (PST) Date: Tue, 18 Feb 2020 16:58:56 -0800 From: Kees Cook To: Sami Tolvanen Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland , james.morse@arm.com, Dave Martin , Laura Abbott , Marc Zyngier , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 12/12] efi/libstub: disable SCS Message-ID: <202002181658.45F66E21F@keescook> References: <20191018161033.261971-1-samitolvanen@google.com> <20200219000817.195049-1-samitolvanen@google.com> <20200219000817.195049-13-samitolvanen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200219000817.195049-13-samitolvanen@google.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 18, 2020 at 04:08:17PM -0800, Sami Tolvanen wrote: > Disable SCS for the EFI stub and allow x18 to be used. > > Suggested-by: James Morse > Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook -Kees > --- > drivers/firmware/efi/libstub/Makefile | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile > index 98a81576213d..dff9fa5a3f1c 100644 > --- a/drivers/firmware/efi/libstub/Makefile > +++ b/drivers/firmware/efi/libstub/Makefile > @@ -30,6 +30,9 @@ KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ > $(call cc-option,-fno-stack-protector) \ > -D__DISABLE_EXPORTS > > +# remove SCS flags from all objects in this directory > +KBUILD_CFLAGS := $(filter-out -ffixed-x18 $(CC_FLAGS_SCS), $(KBUILD_CFLAGS)) > + > GCOV_PROFILE := n > KASAN_SANITIZE := n > UBSAN_SANITIZE := n > -- > 2.25.0.265.gbab2e86ba0-goog > -- Kees Cook