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=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 28189C48BE5 for ; Tue, 15 Jun 2021 19:54:27 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DDAEE61246 for ; Tue, 15 Jun 2021 19:54:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DDAEE61246 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=nH96cGxrwhBXiKhK3phoDBzZKnIpP+TT3qafRSau9k0=; b=b4i9a/x8LQ2gp8 U7SM7BzGg0azN8vYr+tpQiVpLdWVyBzwiZOC5wuV79hJfYpr6FKpzJFxj6XgR67N21KOUlYXF0p59 4XPSqyL4HYtUkZdA9ElWG8JoSS+cX4/S4OrBUuVCBreMVzGD9PU1s96SIrk6k1GQT+3ya/ho5DtWf Y42uV41A5VMctnDLx8pKeWY7rptWHyT/aE4Iw6GO9cKpds9zcy5zztFALSiMwWYBk44wXSuMqmzAk 4FFNfnBkD7Ohb98vhOX1BEkLc2CaDtVv4UfaCM87MOs/SsT429wDne8dauuc6Boex1c6cxDtXuS5e jyx0wktXLtSr3ulaBLmA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ltF6j-002apV-50; Tue, 15 Jun 2021 19:52:22 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ltBCf-0013OE-OY for linux-arm-kernel@lists.infradead.org; Tue, 15 Jun 2021 15:42:15 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1E42E13A1; Tue, 15 Jun 2021 08:42:12 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D71B33F70D; Tue, 15 Jun 2021 08:42:10 -0700 (PDT) Date: Tue, 15 Jun 2021 16:41:08 +0100 From: Dave Martin To: Mark Brown Cc: linux-arch@vger.kernel.org, Yu-cheng Yu , libc-alpha@sourceware.org, Szabolcs Nagy , Catalin Marinas , Jeremy Linton , Will Deacon , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 0/3] arm64: Enable BTI for the executable as well as the interpreter Message-ID: <20210615154106.GS4187@arm.com> References: <20210604112450.13344-1-broonie@kernel.org> <43e67d7b-aab9-db1f-f74b-a87ba7442d47@arm.com> <20210615152203.GR4187@arm.com> <20210615153341.GI5149@sirena.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210615153341.GI5149@sirena.org.uk> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210615_084213_915105_F9FE9021 X-CRM114-Status: GOOD ( 22.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jun 15, 2021 at 04:33:41PM +0100, Mark Brown via Libc-alpha wrote: > On Tue, Jun 15, 2021 at 04:22:06PM +0100, Dave Martin wrote: > > On Thu, Jun 10, 2021 at 11:28:12AM -0500, Jeremy Linton via Libc-alpha wrote: > > > > Thus, I expect that with his patch applied to 5.13 the service will fail to > > > start regardless of the state of MDWE, but it seems to continue starting > > > when I set MDWE=yes. Same behavior with v1 FWTW. > > > If the failure we're trying to detect is that BTI is undesirably left > > off for the main executable, surely replacing BTIs with NOPs will make > > no differenece? The behaviour with PROT_BTI clear is strictly more > > permissive than with PROT_BTI set, so I'm not sure we can test the > > behaviour this way. > > > Maybe I'm missing sometihng / confused myself somewhere. > > The issue this patch series is intended to address is that BTI gets > left off since the dynamic linker is unable to enable PROT_BTI on the > main executable. We're looking to see that we end up with the stricter > permissions checking of BTI, with the issue present landing pads > replaced by NOPs will not fault but once the issue is addressed they > should start faulting. Ah, right -- I got the test backwards in my head. Yes, that sounds reasonable. > > Looking at /proc//maps after the process starts up may be a more > > reliable approach, so see what the actual prot value is on the main > > executable's text pages. > > smaps rather than maps but yes, executable pages show up as "ex" and BTI > adds a "bt" tag in VmFlags. Fumbled that -- yes, I meant smaps! Ignore me... Cheers ---Dave _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel