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=-14.7 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 07DC1C07E99 for ; Mon, 12 Jul 2021 11:57:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E220D610FA for ; Mon, 12 Jul 2021 11:57:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229910AbhGLMAH (ORCPT ); Mon, 12 Jul 2021 08:00:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:32958 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234610AbhGLL7n (ORCPT ); Mon, 12 Jul 2021 07:59:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 101F4610E6; Mon, 12 Jul 2021 11:56:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626091015; bh=Sd2Kflgdz6EMyz+IER+5JzuAgUbhmPO5bzvIfgOgrKw=; h=From:To:Cc:Subject:Date:From; b=EChe/NWCf4LREkd+I/n8uuEYbnOydGa5UWD52J3JnJfbX8XK+IYqsemoJDMAb8FQu NYuQ+AweDPvTDCNLCxGQMP10dbLt1MRFgvnVLwO4oGSTP1SziEZelAuGmD8uxoO+JX srR/jf2yHM4umjsKRV767jH/du0c1nUDSh8BzbZX7qnZdXzJftHLnJzbzUaQklJJMq uL6SADRC07nKCq727l7m4yUxcqxuvsz9qSvwGaheTaMe1NKqfLG8gSiyLW1ms+vmCD XoEcvo+2/hrIVgy+FIhn7m5mru4lTZbpwoPSpcv6OmVxP95UbDth+mRZCAvdEBJqWB ucUmeVw2fOj8w== 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 v4 0/4] arm64: Enable BTI for the executable as well as the interpreter Date: Mon, 12 Jul 2021 12:52:55 +0100 Message-Id: <20210712115259.29547-1-broonie@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2188; h=from:subject; bh=Sd2Kflgdz6EMyz+IER+5JzuAgUbhmPO5bzvIfgOgrKw=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBg7C0WNg8bmv+mBPkYNk6JpHqVu8oqetE1VzSQ69yb 1HyLTy6JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYOwtFgAKCRAk1otyXVSH0JE2B/ 99C7G14IqugPmhEaxUpEuLmGFstEDOw65O6hug9yU2a8cMWwMxV6XHN/PMvrflGeRWwqelO3LkCdon arJFvsRSWaenG+agFSXLbNY+g56aJ6MY3a21DmAyu1Lsj/6d+wPnvwIaetbDAZigjdhXBeUO0UIa7c 7fmqq+eg9foi7H7pOXXlMKcR6WNJJMRkO2OmCpN4JPa/UEd28wGe+nPzn6A5bViFoo9hoyRQz6AdGv PLHLmMpB1FRiREpjh/g5w67dFs0ACEeV8R7GY1al9cq1czoPwbqYm0qVS8MsGb84OkSj1Zi0GuC3pD 0HpAVBD994eQaXm/IUi+gmiFo/kDlm 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. v4: - Rebase onto v5.14-rc1. v3: - Fix passing of properties for parsing by the main executable. - Drop has_interp from arch_parse_elf_property(). - Coding style tweaks. 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 (4): 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() elf: Remove has_interp property from arch_parse_elf_property() arch/arm64/include/asm/elf.h | 13 ++++++++++--- arch/arm64/kernel/process.c | 23 +++++++++++------------ fs/binfmt_elf.c | 33 ++++++++++++++++++++++++--------- include/linux/elf.h | 8 +++++--- 4 files changed, 50 insertions(+), 27 deletions(-) base-commit: e73f0f0ee7541171d89f2e2491130c7771ba58d3 -- 2.20.1