From patchwork Fri Jun 4 11:17:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 43717 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 99988399043B for ; Fri, 4 Jun 2021 11:20:05 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 99988399043B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1622805605; bh=1f+TOGYuO0TGf+gnJ+Pv+R3G4GF7wojFpc4wUXm/BS4=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:Cc:From; b=THudmZhmMnwVSo3Juvouf+KxL2MmNOZEMgjfRMFY0c8//58Sl0jKoc5YWzZpFJ9mT AKpmCSbd5oZ0vwZiBac3mVDjHHmR8mi+dfZ36ibrHPZyvokuBE3auA2Lw7tiSCgSiv qh/l1GtMXZa4X9ke9/vV+hOO/rkY7RToCvrl0TuI= 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 159953848400 for ; Fri, 4 Jun 2021 11:19:44 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 159953848400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 41A8461414; Fri, 4 Jun 2021 11:19:41 +0000 (UTC) To: Catalin Marinas , Will Deacon 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 X-Spam-Status: No, score=-4.0 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, Yu-cheng Yu , libc-alpha@sourceware.org, Szabolcs Nagy , Jeremy Linton , Mark Brown , Dave Martin , linux-arm-kernel@lists.infradead.org Errors-To: libc-alpha-bounces+patchwork=sourceware.org@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. 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