From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by sourceware.org (Postfix) with ESMTPS id 91D2D385C400 for ; Tue, 8 Mar 2022 13:24:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 91D2D385C400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 746ABB81865; Tue, 8 Mar 2022 13:24:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEF85C340EB; Tue, 8 Mar 2022 13:24:28 +0000 (UTC) From: Mark Brown To: Catalin Marinas , Will Deacon Cc: Szabolcs Nagy , Jeremy Linton , "H . J . Lu" , Yu-cheng Yu , Kees Cook , Eric Biederman , linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, libc-alpha@sourceware.org, Mark Brown Subject: [PATCH v11 0/2] arm64: Enable BTI for the executable as well as the interpreter Date: Tue, 8 Mar 2022 13:22:38 +0000 Message-Id: <20220308132240.1697784-1-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2044; h=from:subject; bh=cWHVeZPYv1r1ov1flOwrGDggLr6SS0JvHPeqBo4wpcU=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBiJ1ibOHou9TOSAIZ7+MPC484wx8xzk8Ug0LvT7Zuc lohXQUaJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYidYmwAKCRAk1otyXVSH0DmMB/ 4ueYdiLoK1j8RfnV08DimDkCUOtTYpfo3+vjHdexBaHYHO74sYcNTuzXxHb348Ql3YmFCShAZARHx5 srfldB3c6ez26X5OKKWuKUy3m1TAedkI7zFmWSETcajufRS4RHF00V9IY9nIXssjbCXvblSmI8W8tE Zp69nQ3rhWvjTHv9EjVo5mTwhxIwAcAXq56HOvJ8YSXRUe7h+WBplDLwk8d56ErY6FtgVdYSs0unEX 30QukZbwTd6Xy1IckUfR+ABiHkhOKiKaWYM7otcH2ccFif3iwkSpUgtsOzrIxmpMMu+kDzqVph9Fzi GAp+RATxlofzeigKln2eUz4PFhFUIP X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-5.3 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, T_SCC_BODY_TEXT_LINE 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-List-Received-Date: Tue, 08 Mar 2022 13:24:35 -0000 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 providing a sysctl which when enabled will cause the kernel to handle the BTI property for both the interpreter and the main executable. v11: - Ignore extra PT_INTERPs. v10: - Add a sysctl abi.bti_main controlling the new behaviour. v9: - Rebase onto v5.17-rc3. v8: - Rebase onto v5.17-rc1. v7: - Rebase onto v5.16-rc1. v6: - Rebase onto v5.15-rc1. v5: - Rebase onto v5.14-rc2. - Tweak changelog on patch 1. - Use the helper for interpreter/executable flag in elf.h as well. 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 (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 | 14 ++++++++-- arch/arm64/kernel/process.c | 52 +++++++++++++++++++++++++++--------- fs/binfmt_elf.c | 34 ++++++++++++++++------- include/linux/elf.h | 4 ++- 4 files changed, 78 insertions(+), 26 deletions(-) base-commit: dfd42facf1e4ada021b939b4e19c935dcdd55566 -- 2.30.2