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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 E5C4AC43603 for ; Thu, 5 Dec 2019 09:04:32 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 35BA5205ED for ; Thu, 5 Dec 2019 09:04:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="VHHTxYpi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 35BA5205ED Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17467-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 32563 invoked by uid 550); 5 Dec 2019 09:04:23 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 32543 invoked from network); 5 Dec 2019 09:04:22 -0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=aSbWk7EeCpOIeMzv9/xkKVRKopCYH4/eSh8m9jVb3vY=; b=VHHTxYpiYZAEz9i8xE12I6Rb8 rgRS896TtuujzBoN2nFGRRV80ROgK1VDafD7m9/MAsRTSce8r0gfFktZBwJmEnKyq6D+tCWB/wVFx ZduZOvp4x2W3Ytsh78jUHn0Zheprqm3szyYMITL1QBoNZoAVRBS/UXCM9KPSlcnqcEFE1L1VfxExE yB4/cvW5V3ZfdKypG1dUuA+kSZCCWWakLAGT6jY01pXUBUthu/hifAGswK0VBo20KtmCJoIWg7sun IXy5t0EsACo31AywxBKddaahDD60GwZNH9yGvvtWmG1PP5Ut+XajXe2SGt4BUVgG0XgxX4ZaEbQUH 8vuS3Q5NA==; Date: Thu, 5 Dec 2019 10:03:55 +0100 From: Peter Zijlstra To: Thomas Garnier Cc: kernel-hardening@lists.openwall.com, kristen@linux.intel.com, keescook@chromium.org, Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v10 04/11] x86/entry/64: Adapt assembly for PIE support Message-ID: <20191205090355.GC2810@hirez.programming.kicks-ass.net> References: <20191205000957.112719-1-thgarnie@chromium.org> <20191205000957.112719-5-thgarnie@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191205000957.112719-5-thgarnie@chromium.org> User-Agent: Mutt/1.10.1 (2018-07-13) On Wed, Dec 04, 2019 at 04:09:41PM -0800, Thomas Garnier wrote: > @@ -1625,7 +1627,11 @@ first_nmi: > addq $8, (%rsp) /* Fix up RSP */ > pushfq /* RFLAGS */ > pushq $__KERNEL_CS /* CS */ > - pushq $1f /* RIP */ > + pushq $0 /* Future return address */ We're building an IRET frame, the IRET frame does not have a 'future return address' field. > + pushq %rdx /* Save RAX */ fail.. > + leaq 1f(%rip), %rdx /* RIP */ nonsensical comment > + movq %rdx, 8(%rsp) /* Put 1f on return address */ > + popq %rdx /* Restore RAX */ fail.. > iretq /* continues at repeat_nmi below */ > UNWIND_HINT_IRET_REGS > 1: > -- > 2.24.0.393.g34dc348eaf-goog >