From patchwork Fri May 21 14:46:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 43532 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id C2670398E44D; Fri, 21 May 2021 14:50:52 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C2670398E44D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1621608652; bh=Q/z8G21uaZlwX1L81U2pozkKGvbTyminqdU14YTeVrc=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:Cc:From; b=nGmfDUYFXQLpeTgWnZtDzMhznQbiXIHAf2s2eG2q4iTH6sC0Xeunup2nZiajcDAEG joMqubyPU/8Ff1tm63QLj73lSvyL9G61lwzTZ3PQilBtUaLHKrQak7iTdPFcBoqLbh YjNlNTCUz4X1FVrdp04BG+O4IzTgyCy5mOCoe1JA= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by sourceware.org (Postfix) with ESMTPS id 8904D398B8B4 for ; Fri, 21 May 2021 14:50:49 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 8904D398B8B4 Received: by mail.kernel.org (Postfix) with ESMTPSA id 15C1761244; Fri, 21 May 2021 14:50:47 +0000 (UTC) To: Catalin Marinas , Will Deacon 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 X-Spam-Status: No, score=-3.6 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Mark Brown via Libc-alpha From: Mark Brown Reply-To: Mark Brown Cc: linux-arch@vger.kernel.org, libc-alpha@sourceware.org, Szabolcs Nagy , Jeremy Linton , Mark Brown , Dave Martin , linux-arm-kernel@lists.infradead.org Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" 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