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=-14.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 BE02DC47083 for ; Fri, 4 Jun 2021 11:19:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BE906141E for ; Fri, 4 Jun 2021 11:19:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230161AbhFDLV2 (ORCPT ); Fri, 4 Jun 2021 07:21:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:56980 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229962AbhFDLV1 (ORCPT ); Fri, 4 Jun 2021 07:21:27 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 41A8461414; Fri, 4 Jun 2021 11:19:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622805581; bh=+xnPy6vKSA4JZpieqy9rOye/hz55CPiRF8qm7EZ7dLQ=; h=From:To:Cc:Subject:Date:From; b=CdBAtHrb/IrZ68ti6U3G95wP6ubSCd4JFz9u2WJ6iln4+xnkM+4Hmoke4VsbLIIPP HwtyskbcOBzpDShXl9qvJyx356tdTHZAo3hJDlFypPSwSwiIoO/QZ4I3yFeTee/Oj9 d2kthGv5HyNcD+Ngidc5IKotNOWjJz6jofFSWdv4PZM2yBCYi9mV4BRdUgYeQ+rdYU AGAWp1xaSOjH6HmpLuYGlNFuxrAJXEG0RHwQTIr+/its+Vjq++1toyHGpB2Kp9xDdp iqBk4OS2z+7efshnUrZCNq4ahychBeIBC3oQ7qYNd+/9BeMu2Uw6zTGr94oFw8oBVI fNTecdt7NY2EQ== From: Mark Brown To: Catalin Marinas , Will Deacon Cc: Szabolcs Nagy , Jeremy Linton , Dave Martin , "H . J . Lu" , Yu-cheng Yu , linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, libc-alpha@sourceware.org, Mark Brown Subject: [PATCH v1 0/3] arm64: Enable BTI for the executable as well as the interpreter Date: Fri, 4 Jun 2021 12:17:25 +0100 Message-Id: <20210604111728.12052-1-broonie@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1935; h=from:subject; bh=+xnPy6vKSA4JZpieqy9rOye/hz55CPiRF8qm7EZ7dLQ=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBgugvEP0DyUOyeqjIBzn0tFkh5xzY2HcRp/M4GxMOy 7l9nn6GJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYLoLxAAKCRAk1otyXVSH0Dz3B/ 0R1jseSi1DxRO3mtnP3vbBTPEX5UpFMZfI7SC3alRjKEgcMjHQZ+R/rUviWNQUnugrRW9Cc6aXlpMb kNnOMaL41yG2i/j+/VD6tpMCaPTNPLh1ilJF9i3ve5L6VBH9ymsSlL6fj0tQIkMR7iTG1fUq/YQD/b j43T3Wyd1YOfgZeaS8IYVVyiqXxoT0TivYu4CqeKKIg5dTqJNPjJCTqHaKNBYKttEydE1xlsuKXVjs RqzdUEMs9MDbWo6UD6rnf8EJTFo6V3KoC8ZagdCwGqdnC+ZcLyjPYXWnIrtRMlR4TRvvbUYgrf+kAW BodmOA+/cPU157Oy4McKoCvrYWAp7c X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Deployments of BTI on arm64 have run into issues interacting with systemd's MemoryDenyWriteExecute feature. Currently for dynamically linked executables the kernel will only handle architecture specific properties like BTI for the interpreter, the expectation is that the interpreter will then handle any properties on the main executable. For BTI this means remapping the executable segments PROT_EXEC | PROT_BTI. This interacts poorly with MemoryDenyWriteExecute since that is implemented using a seccomp filter which prevents setting PROT_EXEC on already mapped memory and lacks the context to be able to detect that memory is already mapped with PROT_EXEC. This series resolves this by handling the BTI property for both the interpreter and the main executable. This does mean that we may get more code with BTI enabled if running on a system without BTI support in the dynamic linker, this is expected to be a safe configuration and testing seems to confirm that. It also reduces the flexibility userspace has to disable BTI but it is expected that for cases where there are problems which require BTI to be disabled it is more likely that it will need to be disabled on a system level. v2: - Add a patch dropping has_interp from arch_adjust_elf_prot() - Fix bisection issue with static executables on arm64 in the first patch. Mark Brown (3): elf: Allow architectures to parse properties on the main executable arm64: Enable BTI for main executable as well as the interpreter elf: Remove has_interp property from arch_adjust_elf_prot() arch/arm64/include/asm/elf.h | 13 ++++++++++--- arch/arm64/kernel/process.c | 20 +++++++------------- fs/binfmt_elf.c | 29 ++++++++++++++++++++--------- include/linux/elf.h | 8 +++++--- 4 files changed, 42 insertions(+), 28 deletions(-) base-commit: c4681547bcce777daf576925a966ffa824edd09d -- 2.20.1