From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FORGED_GMAIL_RCVD, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS, URIBL_BLOCKED shortcircuit=no autolearn=no autolearn_force=no version=3.4.2 Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id BCBC91F463 for ; Thu, 12 Dec 2019 15:57:41 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-type; q=dns; s=default; b=HCZA +p3CEGwrVq6efwDXufsYtt6Nf619yH03JnBWFyQda+vkc+4HF4BDt3XnU8JR3aMR xILnoebQ7RMVOvIc060NPoPXxq9FDW5nG9d2zvPw2+IJ4FG0ds3J5R7bLZt/oUWQ k+9yB2KNr3c4lR7cVFbQAE3AqXFsILiXIe1HwMQ= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-type; s=default; bh=3CklKxbmo5 HKVVLjwxjN1nR0xBA=; b=uAjFK0yPdQoWPTk9xyCVGO7odiCB1EBBmd22IlUh0o jTuC3Wd2R+g4kmD7tBET8sQBlVTybWm2KhDgUwgM9uH1qNqYNwwAEPyEMLkX4f43 Ms0L+N20RPhUID4BDI5Vg6+KXmi0yMiWqhychom+RFi0vc6QNnoaZVI9dEKHMwPH 0= Received: (qmail 118587 invoked by alias); 12 Dec 2019 15:57:39 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 118579 invoked by uid 89); 12 Dec 2019 15:57:39 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: mail-oi1-f195.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=zwS+B73L68WU3d3fiGHheDj5CgShp1rj/l+k8OKKQ/4=; b=rklZGKSOunf0I0mRw3PUOLvTv453i4M6FADhob1NztBHlG+cdaUcHNPxu/wRZY5Zhj XxPLrxIvy0g+3phLwd+Xnm/gSPzNitJbDj7JnY/gJza0FgjaMOuM78meVxmWFmA+GbB4 cOIIXJXl4QtcjYyyi4K2c9yZlHyUUT1ze+2wHu/uqkp3cZTlh6IiTb6yskKzEYPykkIV CBS7nCvPzRJPxH4/fSxERsffwf5Csrly/VjaMpCMy+JCXcIFfzvcFJ3sE/56GGd/KGsn 3ZIQnciI0YiCaFNKbtrpWQfUY+17omIHWFsB3tn5ODQcD9USjS68AOHZn6G4JCs4VnYi gNcQ== MIME-Version: 1.0 References: <20191210204710.4832-1-hjl.tools@gmail.com> <878snhhft7.fsf@oldenburg2.str.redhat.com> In-Reply-To: <878snhhft7.fsf@oldenburg2.str.redhat.com> From: "H.J. Lu" Date: Thu, 12 Dec 2019 07:57:00 -0800 Message-ID: Subject: Re: [PATCH 0/4] i386: Finish CET support To: Florian Weimer Cc: GNU C Library Content-Type: text/plain; charset="UTF-8" On Thu, Dec 12, 2019 at 4:46 AM Florian Weimer wrote: > > * H. J. Lu: > > > This patch set finishes CET support on i386: > > > > 1. getcontext, setcontext and swapcontext are updated not to preserve > > EAX, ECX and EDX. Since they are caller-saved, caller will reload them > > after getcontext, setcontext and swapcontext calls if needed. The extra > > scratch registers are used to enable CET. > > 2. Add missing _CET_ENDBR to i386 assembly files. > > 3. Enable CET support in i386 ucontext functions. > > > > Tested on i386 CET/non-CET machines. > > Has the kernel ABI been finalized? These parts of kernel ABI haven't been changed. > I wonder if we should add IFUNC resolvers which set a flag, and check > that flag at the start of (some of) these functions, so that they cannot > be used as ROP gadgets in programs that do not reference them. > What exactly do you have in mind? -- H.J.