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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07BD0C04A94 for ; Fri, 11 Aug 2023 16:38:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 839066B0074; Fri, 11 Aug 2023 12:38:34 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 810816B0078; Fri, 11 Aug 2023 12:38:34 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6D9C16B007B; Fri, 11 Aug 2023 12:38:34 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 60C3C6B0074 for ; Fri, 11 Aug 2023 12:38:34 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 3292F1C9605 for ; Fri, 11 Aug 2023 16:38:34 +0000 (UTC) X-FDA: 81112382148.21.2FCA561 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf19.hostedemail.com (Postfix) with ESMTP id 537DF1A0015 for ; Fri, 11 Aug 2023 16:38:32 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=none; spf=pass (imf19.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1691771912; a=rsa-sha256; cv=none; b=Ji+49I8hFUKUhwDldG3LVCh6xVqrsW/c1plaOOjcYSV9EtrLdnRnFfzXcKqc2TpRmO2eTe BWPNQU/ZkEyjB4CaTrMeaaP/Gv861RJFGAgSUXa5YwhvbnK45BtUQPh19R98htMvgsh+Qk M0Z87HbSz8ut5+ldDb4VRzKG1biE3WI= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=none; spf=pass (imf19.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1691771912; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aku5mBlEWjIn3HF65aYhbt8EFBdr24wGir9Opl+4J70=; b=tCww2hHSypbEJxI5fXgeonsBOP+eAEfXPzIW1iKTzBx6oqNzjEoYl6BdTnl0YJhp/STy5K r+ZN83bJMY2RQecVnFv48amG5vVSV4TGMN3N/kQLS/Asnr/Voonh1fAZF7fOFyPU1DSWBh ijccb25EFrYgZdIZJThizJwApfLpQDM= Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8EB84676AA; Fri, 11 Aug 2023 16:38:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73644C433C7; Fri, 11 Aug 2023 16:38:26 +0000 (UTC) Date: Fri, 11 Aug 2023 17:38:24 +0100 From: Catalin Marinas To: Mark Brown Cc: Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Kees Cook , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v4 21/36] arm64/mm: Implement map_shadow_stack() Message-ID: References: <20230807-arm64-gcs-v4-0-68cfa37f9069@kernel.org> <20230807-arm64-gcs-v4-21-68cfa37f9069@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230807-arm64-gcs-v4-21-68cfa37f9069@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 537DF1A0015 X-Stat-Signature: ynrr7i9a7rhkytq5xxiyo6xms84zsgzz X-HE-Tag: 1691771912-515454 X-HE-Meta: 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 oLISB7Gq 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Aug 07, 2023 at 11:00:26PM +0100, Mark Brown wrote: > As discussed extensively in the changelog for the addition of this > syscall on x86 ("x86/shstk: Introduce map_shadow_stack syscall") the > existing mmap() and madvise() syscalls do not map entirely well onto the > security requirements for guarded control stacks since they lead to > windows where memory is allocated but not yet protected or stacks which > are not properly and safely initialised. Instead a new syscall > map_shadow_stack() has been defined which allocates and initialises a > shadow stack page. I guess I need to read the x86 discussion after all ;). Given that we won't have an mmap(PROT_SHADOW_STACK), are we going to have restrictions on mprotect()? E.g. it would be useful to reject a PROT_EXEC on the shadow stack. -- Catalin