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=-11.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,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 33508C433B4 for ; Wed, 28 Apr 2021 20:39:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0308161445 for ; Wed, 28 Apr 2021 20:39:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242011AbhD1Uj5 (ORCPT ); Wed, 28 Apr 2021 16:39:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234904AbhD1Ujz (ORCPT ); Wed, 28 Apr 2021 16:39:55 -0400 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCF74C06138D for ; Wed, 28 Apr 2021 13:39:08 -0700 (PDT) Received: by mail-pg1-x52e.google.com with SMTP id t22so10347344pgu.0 for ; Wed, 28 Apr 2021 13:39:08 -0700 (PDT) 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=Z3WAVPi6tsHxDYkM4thG7PqVeXUU++9bnDuXCoKXmi4=; b=ZmnkDIBH98NF1kICfHfEsAXDmL81P1i5sho5DoEipnWM1JRdebMvTIFIB3EZrdbxZn y8ClFZHg8i8gUYF0PnrIs3G4b/r+BytJNDQ4uhlC+MiMF0Kec0BZ7gn7keoVd6VL500d WrrbVntXIXFqljgruoN87fy+qSt9FsFRYjSW4= 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=Z3WAVPi6tsHxDYkM4thG7PqVeXUU++9bnDuXCoKXmi4=; b=nFXpCyJa+V5edzsbfxygDRNuZMkOSZrH7Gssu9tNZay0tddVskt6Vzy2dO0l2JzJgA KAQlkNyVHm3oUSGYCLHaozQK6hX6iMG8R2u3LIEmzTJR6XMMfqfI5/NqeQHwEJxyM2c9 V3yixTx2aJ1C6nHkkSZrORBm3tGl76mhSMKRyHKPjr3j/fFkftD4HNCLxcKZbX70au09 XOLeccn7Yj6OpKmegwaZ/SA3lO+XuB+eNOudE6Zvoct9DijpXbUxizmJuf1phrVTUz6/ IcKlBCD49jcDhMHyGA5rHJV19bXk5pCiI7UC2mFHYZ2M1FSOxGT4TDUWsQmNl6kujxFB YcGA== X-Gm-Message-State: AOAM532uBdhqHznhx0G7AzHIR3zxfbVy+HFBbGRvWexrAmoTbx35s9k5 /zMrUBIOHgjOYAvbAFmcidsFMQ== X-Google-Smtp-Source: ABdhPJz5qNc4ZUSIrp+d0WTSSyiaj2Rw5P4r2NUtbl4ssPsBN5WfJR8zNykqUu9f6aJ+oaWb6HqSaA== X-Received: by 2002:a05:6a00:170c:b029:225:8851:5b3c with SMTP id h12-20020a056a00170cb029022588515b3cmr29728717pfc.0.1619642348454; Wed, 28 Apr 2021 13:39:08 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id e10sm493387pfc.40.2021.04.28.13.39.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Apr 2021 13:39:07 -0700 (PDT) Date: Wed, 28 Apr 2021 13:39:07 -0700 From: Kees Cook To: Yu-cheng Yu 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 , 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 v26 8/9] x86/vdso/32: Add ENDBR to __kernel_vsyscall entry point Message-ID: <202104281339.F0CA6CA3E@keescook> References: <20210427204720.25007-1-yu-cheng.yu@intel.com> <20210427204720.25007-9-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210427204720.25007-9-yu-cheng.yu@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Tue, Apr 27, 2021 at 01:47:19PM -0700, Yu-cheng Yu wrote: > From: "H.J. Lu" > > 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 that to __kernel_vsyscall entry point. > > Signed-off-by: H.J. Lu Reviewed-by: Kees Cook -- Kees Cook