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=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 59979C433E9 for ; Wed, 17 Mar 2021 01:43:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 326FB64F9C for ; Wed, 17 Mar 2021 01:43:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229482AbhCQBmq (ORCPT ); Tue, 16 Mar 2021 21:42:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:33062 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229732AbhCQBml (ORCPT ); Tue, 16 Mar 2021 21:42:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2207D64F8A; Wed, 17 Mar 2021 01:42:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615945360; bh=3alGDHmFzxfE1mdJkhw6gRfUK9karXuKpaVclegdMGw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=a3JMvDsBkYu8vglQt41do9DQmoqEzJz0hL8G/e+PDIA/RkjzuA5ldzVBrxyg7cE4O NeOv9K5ZNQGHSVHF3le+I2Sda1le7MH1EWKPo4g4Z7vBAhq2wXBBPFCLMnfFgPRDUK XEMIif4tdw9zABchIZGY5bMNcMXdR++pBmzjB50WjqtlJ7JR0Zt8rac+U0L2k0V38C Uhv4O4kKkutrBdEsZRmcr5ISzz2zyMzGCnvbyFmsGuLjxfgyrYNS//gTypbnwec3BE 4NcnEs5VpPhR64MMTaLvPuQpf/WXSZGzKFE8cQt7BuPWdBagw8DnOR7gRzqGWYJDc0 GspaLWwllW+Yw== Date: Wed, 17 Mar 2021 03:42:15 +0200 From: Jarkko Sakkinen To: "Yu, Yu-cheng" Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang Subject: Re: [PATCH v23 9/9] x86/vdso: Add ENDBR to __vdso_sgx_enter_enclave Message-ID: References: <20210316151320.6123-1-yu-cheng.yu@intel.com> <20210316151320.6123-10-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Tue, Mar 16, 2021 at 12:27:19PM -0700, Yu, Yu-cheng wrote: > On 3/16/2021 12:22 PM, Jarkko Sakkinen wrote: > > On Tue, Mar 16, 2021 at 08:13:19AM -0700, Yu-cheng Yu wrote: > > > ENDBR is a special new instruction for the Indirect Branch Tracking (IBT) > > > component of CET. IBT prevents attacks by ensuring that (most) indirect > > > branches and function calls may only land at ENDBR instructions. Branches > > > that don't follow the rules will result in control flow (#CF) exceptions. > > > > > > ENDBR is a noop when IBT is unsupported or disabled. Most ENDBR > > > instructions are inserted automatically by the compiler, but branch > > > targets written in assembly must have ENDBR added manually. > > > > > > Add ENDBR to __vdso_sgx_enter_enclave() branch targets. > > > > > > Signed-off-by: Yu-cheng Yu > > > Cc: Andy Lutomirski > > > Cc: Borislav Petkov > > > Cc: Dave Hansen > > > Cc: Jarkko Sakkinen > > > Cc: Peter Zijlstra > > > --- > > > arch/x86/entry/vdso/vsgx.S | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > diff --git a/arch/x86/entry/vdso/vsgx.S b/arch/x86/entry/vdso/vsgx.S > > > index 86a0e94f68df..1baa9b49053e 100644 > > > --- a/arch/x86/entry/vdso/vsgx.S > > > +++ b/arch/x86/entry/vdso/vsgx.S > > > @@ -6,6 +6,7 @@ > > > #include > > > #include "extable.h" > > > +#include "../calling.h" > > > /* Relative to %rbp. */ > > > #define SGX_ENCLAVE_OFFSET_OF_RUN 16 > > > @@ -27,6 +28,7 @@ > > > SYM_FUNC_START(__vdso_sgx_enter_enclave) > > > /* Prolog */ > > > .cfi_startproc > > > + ENDBR > > > push %rbp > > > .cfi_adjust_cfa_offset 8 > > > .cfi_rel_offset %rbp, 0 > > > @@ -62,6 +64,7 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave) > > > .Lasync_exit_pointer: > > > .Lenclu_eenter_eresume: > > > enclu > > > + ENDBR > > > /* EEXIT jumps here unless the enclave is doing something fancy. */ > > > mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx > > > @@ -91,6 +94,7 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave) > > > jmp .Lout > > > .Lhandle_exception: > > > + ENDBR > > > mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx > > > /* Set the exception info. */ > > > -- > > > 2.21.0 > > > > > > > > > > Looks good to me. > > > > Reviewed-by: Jarkko Sakkinen > > Thanks for reviewing. In response to Dave's and Boris' comments, I will > replace ENDBR macro with _CET_ENDBR that comes from the compiler. Can I > still keep the Reviewed-by? I'll rather re-ack, thanks. Most likely give reviewed-by but I always prefer to see the code change before doing that. /Jarkko