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=-8.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 54705C433E0 for ; Wed, 10 Jun 2020 07:31:07 +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 26E802081A for ; Wed, 10 Jun 2020 07:31:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="eRAgssbx"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="kurjwS8f" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 26E802081A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject: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=UvrvTmXvLc8Gj9fcKiPdfpyP4R9HVM9s/PCy9IBHvJM=; b=eRAgssbxAoppIM i5dyQJV9h3CcUcd/pFg4boRESf0zBtdt5RsEWt2qCB1Y2tStOTQtXmgElg0FTnMxFN6O8wHPKRjuB fT3sJ39rjX9b8EL++IPbKZExCTa8WWjsuujHiJcD9VtLIEVOsrfm7LBTY9TPRs80K473drMq5q/fa azhD0v8f1XTHfw4YnQgpWfktUDmOBNV4zjHH1jQxmleTXLOajguqFU9H4XiDl+tJh/RkfKi179nIk uFK6M4+jW7fqfcRR1/pyQ6ZpCPmSfap9ajoAcvhpNqfylfpbC+cC73QhFTtohhxPlHw6dqslX6bbC /8Q4Ae2Nz+/m0McYC4tw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jivCN-0007QF-R0; Wed, 10 Jun 2020 07:30:59 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jivCK-0007Pj-8o for linux-arm-kernel@lists.infradead.org; Wed, 10 Jun 2020 07:30:57 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BE19D2064C; Wed, 10 Jun 2020 07:30:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591774255; bh=IH/VSuSEAGvCmDHtwWjVeUZ11F3kkh8B0kP5JWifwc8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kurjwS8fwiw8EGn0jbytoas/wrEj4xJkUEgxJkvcozH24JD2dlC5y+a4nJD0My3sq ul+wjivjzSARUMXtVw/lGNKsv6f0Tp7jqRq/C1+iXJ6YGLS7CKEkCCFlbDtWNARzK4 Peuog3YYkCA20WJGXvYxTvu65RcFJjBDad24TU9U= Date: Wed, 10 Jun 2020 08:30:47 +0100 From: Will Deacon To: Kees Cook Subject: Re: [PATCH 5/5] gcc-plugins/stackleak: Don't instrument vgettimeofday.c in arm64 VDSO Message-ID: <20200610073046.GA15939@willie-the-truck> References: <20200604134957.505389-1-alex.popov@linux.com> <20200604134957.505389-6-alex.popov@linux.com> <20200604135806.GA3170@willie-the-truck> <202006091149.6C78419@keescook> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <202006091149.6C78419@keescook> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200610_003056_351685_9EE343A6 X-CRM114-Status: GOOD ( 22.68 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kernel-hardening@lists.openwall.com, Catalin Marinas , Masahiro Yamada , Vincenzo Frascino , Sven Schnelle , Naohiro Aota , Masahiro Yamada , x86@kernel.org, Emese Revfy , Iurii Zaikin , PaX Team , Laura Abbott , Mathias Krause , Alexander Popov , linux-kbuild@vger.kernel.org, Alexander Monakov , Michal Marek , Thomas Gleixner , Peter Collingbourne , linux-arm-kernel@lists.infradead.org, notify@kernel.org, Florian Weimer , gcc@gcc.gnu.org, Brad Spengler , linux-kernel@vger.kernel.org, Miguel Ojeda , Luis Chamberlain , Jessica Yu , Andrew Morton , Thiago Jung Bauermann Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jun 09, 2020 at 12:09:27PM -0700, Kees Cook wrote: > On Thu, Jun 04, 2020 at 02:58:06PM +0100, Will Deacon wrote: > > On Thu, Jun 04, 2020 at 04:49:57PM +0300, Alexander Popov wrote: > > > Don't try instrumenting functions in arch/arm64/kernel/vdso/vgettimeofday.c. > > > Otherwise that can cause issues if the cleanup pass of stackleak gcc plugin > > > is disabled. > > > > > > Signed-off-by: Alexander Popov > > > --- > > > arch/arm64/kernel/vdso/Makefile | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile > > > index 3862cad2410c..9b84cafbd2da 100644 > > > --- a/arch/arm64/kernel/vdso/Makefile > > > +++ b/arch/arm64/kernel/vdso/Makefile > > > @@ -32,7 +32,8 @@ UBSAN_SANITIZE := n > > > OBJECT_FILES_NON_STANDARD := y > > > KCOV_INSTRUMENT := n > > > > > > -CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables > > > +CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables \ > > > + $(DISABLE_STACKLEAK_PLUGIN) > > > > I can pick this one up via arm64, thanks. Are there any other plugins we > > should be wary of? It looks like x86 filters out $(GCC_PLUGINS_CFLAGS) > > when building the vDSO. > > I didn't realize/remember that arm64 retained the kernel build flags for > vDSO builds. (I'm used to x86 throwing all its flags away for its vDSO.) > > How does 32-bit ARM do its vDSO? > > My quick run-through on plugins: > > arm_ssp_per_task_plugin.c > 32-bit ARM only (but likely needs disabling for 32-bit ARM vDSO?) On arm64, the 32-bit toolchain is picked up via CC_COMPAT -- does that still get the plugins? > cyc_complexity_plugin.c > compile-time reporting only > > latent_entropy_plugin.c > this shouldn't get triggered for the vDSO (no __latent_entropy > nor __init attributes in vDSO), but perhaps explicitly disabling > it would be a sensible thing to do, just for robustness? > > randomize_layout_plugin.c > this shouldn't get triggered (again, lacking attributes), but > should likely be disabled too. > > sancov_plugin.c > This should be tracking the KCOV directly (see > scripts/Makefile.kcov), which is already disabled here. > > structleak_plugin.c > This should be fine in the vDSO, but there's not security > boundary here, so it wouldn't be important to KEEP it enabled. Thanks for going through these. In general though, it seems like an opt-in strategy would make more sense, as it doesn't make an awful lot of sense to me for the plugins to be used to build the vDSO. So I would prefer that this patch filters out $(GCC_PLUGINS_CFLAGS). Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel