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 3E5BAC47076 for ; Fri, 21 May 2021 14:50:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 10F5E613E6 for ; Fri, 21 May 2021 14:50:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233535AbhEUOwM (ORCPT ); Fri, 21 May 2021 10:52:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:46698 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232057AbhEUOwL (ORCPT ); Fri, 21 May 2021 10:52:11 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 15C1761244; Fri, 21 May 2021 14:50:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621608648; bh=E5SzQf7ojZwGymmxW8Bc1NkGOtaRDaagBD9U0Qp0b/w=; h=From:To:Cc:Subject:Date:From; b=Grnf/yMvIW9dOoCQ8uwsNGREdpj2+0QcPA960wIWctSTfnA++cRMOTNwdA/n1C3rC wAxD3MFjrThBrxOW6cy+q1Ny3JFSQHWls3mWnuphSqHK9GIxnPOaalAGS/iIBxBzG6 zKBViCcJhXMDc4jnABcEQy6Y6gzpbsDOqZEGXLsYvGUHduxD+bPYsicT5BwFckP7Gp S86I6L+ursESEq7kmyWEyngnRF5cs8dAByq1EbLiYaQp/V6qYonP7urhpyfbDcK12e DMuO34bI3Xm3DjSISBxjMIGccWgShB7tPkk+vxID5fkOoDa3XN6o9jMWD9+bom0Gnr d4tmkG21b8k2g== From: Mark Brown To: Catalin Marinas , Will Deacon Cc: Szabolcs Nagy , Jeremy Linton , Dave Martin , "H . J . Lu" , linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, libc-alpha@sourceware.org, Mark Brown Subject: [PATCH v1 0/2] arm64: Enable BTI for the executable as well as the interpreter Date: Fri, 21 May 2021 15:46:19 +0100 Message-Id: <20210521144621.9306-1-broonie@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1710; h=from:subject; bh=E5SzQf7ojZwGymmxW8Bc1NkGOtaRDaagBD9U0Qp0b/w=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBgp8e52rx52kLo8ejZvd+0QpndI56sS+egfvpy0gFl 8tZS3YCJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYKfHuQAKCRAk1otyXVSH0Ot5B/ 9aitjdhLxWBsekuYePmiJmZPaWIADO334zfYOAdSHJcD47YTrOcyg3Z8kxwjbNnG2ToLMD6z1cyvg9 mQ4GBWtwpTIFIpF7jW/QY3z6Fmj/r8XGCbZnuT1yt2f3mTbK37CeVaOspLlKzpI6TjdBWiCpBP0hQI PJLFaYGgJVIdbEQg6k6z9hCcw2a8ZLgmCJqTstPauqfZHr91Mqm2FiHPpAND9r2V/02OWPRFpugrqN +O1kdXvcK4kQVneMvUpnwL88qmHV1meWC7BgiyX13ObgXFCqIiedyJeFYVjPkAk+leFx6+AOjXaIkM OoPRUShYch582Q1TjhyftmKQjJYZYr 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. Mark Brown (2): elf: Allow architectures to parse properties on the main executable arm64: Enable BTI for main executable as well as the interpreter arch/arm64/include/asm/elf.h | 13 ++++++++++--- arch/arm64/kernel/process.c | 18 ++++++------------ fs/binfmt_elf.c | 25 +++++++++++++++++-------- include/linux/elf.h | 4 +++- 4 files changed, 36 insertions(+), 24 deletions(-) base-commit: d07f6ca923ea0927a1024dfccafc5b53b61cfecc -- 2.20.1