From patchwork Mon Jul 12 11:52:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 44313 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 5B1163888807 for ; Mon, 12 Jul 2021 11:57:27 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5B1163888807 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1626091047; bh=F0yjDmOYnIT6dMfyp91Cby+GwDbVKmdSAImXixDzizw=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:Cc:From; b=SLMlqrKIVx5deW0WN+Y6wOvxi3TY+MNKc2hYIWDh74Fw7O5sX+OwspGfbGfiFxiDd Sietv/U0LqMm8AU0xzjZod4xhL7oUCSEWi4/sFrVU+In1YR+j40vs1jk4p/cGZPs4P HMYnAFzetsVtdCgPS3PUbCbOr1mMjQxJhTZUGMrg= 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 644D83888807 for ; Mon, 12 Jul 2021 11:56:57 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 644D83888807 Received: by mail.kernel.org (Postfix) with ESMTPSA id 101F4610E6; Mon, 12 Jul 2021 11:56:54 +0000 (UTC) To: Catalin Marinas , Will Deacon 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 X-Spam-Status: No, score=-5.0 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=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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. 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