From patchwork Sun Jul 16 21:50:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13314916 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D558CEB64DD for ; Sun, 16 Jul 2023 21:53:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230374AbjGPVw7 (ORCPT ); Sun, 16 Jul 2023 17:52:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52248 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229547AbjGPVw6 (ORCPT ); Sun, 16 Jul 2023 17:52:58 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 24404E40; Sun, 16 Jul 2023 14:52:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A97A860E71; Sun, 16 Jul 2023 21:52:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F0CAC433D9; Sun, 16 Jul 2023 21:52:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689544376; bh=pjsLx6b1K0x937g9y/oHkxJKpquxYt6WMLA+SQZbCw0=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=D6u3/V1MrlLBNBjRRjCkDs71lTKKLdxk4UVJjERzJR5KtW04sDJdFN6DY4BPTv7r0 aTfNC0/NB9GX79XAFYhU9VdVRzw7MQZB2TF5LJweHmcGzRshXudBtlTD2haZIuC5LP NaMVrAzn6EMq6cEbwRZ7uCadAgG/757FAaXVcG059B2O2THi3ybHajqxcaPXT14ni/ 6NChUcGdOlfnZpMRnwjiRdGcw3nrq4zpyK9Bx75LgEsUYLdTuKOLC/IWjPFQaqy28Z elrpk8hcyukSHOh6r8e7/i+jKu2gyDkRcAfCoKCGTMq/2lOlXbHU4FnmZICc8ziKLS FgyPVP92q+o+A== From: Mark Brown Date: Sun, 16 Jul 2023 22:50:57 +0100 Subject: [PATCH 01/35] prctl: arch-agnostic prctl for shadow stack MIME-Version: 1.0 Message-Id: <20230716-arm64-gcs-v1-1-bf567f93bba6@kernel.org> References: <20230716-arm64-gcs-v1-0-bf567f93bba6@kernel.org> In-Reply-To: <20230716-arm64-gcs-v1-0-bf567f93bba6@kernel.org> To: Catalin Marinas , Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Kees Cook , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy Cc: "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Mark Brown X-Mailer: b4 0.13-dev-099c9 X-Developer-Signature: v=1; a=openpgp-sha256; l=3582; i=broonie@kernel.org; h=from:subject:message-id; bh=98fSp9zoycOoO4JRBJGcJJdFtBdtqinfhtbljBoqJQI=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBktGaPOeEvYK+HaBvmOtGw+GIVwaAEnOI6agwGJ0VT 4ZZsfRKJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZLRmjwAKCRAk1otyXVSH0BEJB/ 9TsUZy5D4ijFFo1Dfdcl7QkdIYj1UVRzxptIb9l671dL338Gc6GZhPmT4VkT3f+hyJjVzVSMK0BwQx 7fE6Izud5qO6BfUkfyU51nyNtrLB7yLggC9+jRTraTvq081sRTpALcQTMwAYjiw8BoH1aDx04+TDp5 m9GAxFLqSAzAvANMpV53ulubFEhZCOy172JSzFniKE4JCODuwQFC/Lc1Ze7H5Y8LHJoEx4NnI3FvY5 hCcDa2LqJ6vTvaleevbA95bGiuxuE3DnaUGiWqcw/ZREbyi7SKv2jlGrWefGv7OMxEAHprq0ZEDBHW aTwFGtJ3i24vZYlTquUCFDGTC9O7Iw X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Deepak Gupta Three architectures (x86, aarch64, riscv) have announced support for shadow stack. This patch adds arch-agnostic prtcl support to enable /disable/get/set status of shadow stack and forward control (landing pad) flow cfi statuses. New prctls are - PR_GET_SHADOW_STACK_STATUS, PR_SET_SHADOW_STACK_STATUS Signed-off-by: Deepak Gupta [Rebased onto current kernels, renumbering to track other allocations already upstream, dropping indirect LP, updating to pass arg to set by value, fix missing prototypes for weak functions and update title. -- broonie] Signed-off-by: Mark Brown --- include/linux/mm.h | 3 +++ include/uapi/linux/prctl.h | 17 +++++++++++++++++ kernel/sys.c | 20 ++++++++++++++++++++ 3 files changed, 40 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 97eddc83d19c..bf16edf2fcd9 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3947,4 +3947,7 @@ static inline void accept_memory(phys_addr_t start, phys_addr_t end) #endif +int arch_get_shadow_stack_status(struct task_struct *t, unsigned long __user *status); +int arch_set_shadow_stack_status(struct task_struct *t, unsigned long status); + #endif /* _LINUX_MM_H */ diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 3c36aeade991..9fdc77fa2bfe 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -305,4 +305,21 @@ struct prctl_mm_map { # define PR_RISCV_V_VSTATE_CTRL_NEXT_MASK 0xc # define PR_RISCV_V_VSTATE_CTRL_MASK 0x1f +/* + * get shadow stack status for current thread. Assumes shadow stack is min 4 byte aligned. + * Note shadow stack can be 8 byte aligned on 64bit. + * Lower 2 bits can give status of locked and enabled/disabled. + * size and address range can be obtained via /proc/maps. get_shadow_stack_status will + * return base of shadow stack. + */ +#define PR_GET_SHADOW_STACK_STATUS 71 +/* + * set shadow stack status for current thread (including enabling, disabling or locking) + * note that it will only set the status and setup of the shadow stack. Allocating shadow + * stack should be done separately using mmap. + */ +#define PR_SET_SHADOW_STACK_STATUS 72 +# define PR_SHADOW_STACK_LOCK (1UL << 0) +# define PR_SHADOW_STACK_ENABLE (1UL << 1) + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 05f838929e72..ebf9ea5f0fae 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2302,6 +2302,16 @@ int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which, return -EINVAL; } +int __weak arch_get_shadow_stack_status(struct task_struct *t, unsigned long __user *status) +{ + return -EINVAL; +} + +int __weak arch_set_shadow_stack_status(struct task_struct *t, unsigned long status) +{ + return -EINVAL; +} + #define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE) #ifdef CONFIG_ANON_VMA_NAME @@ -2720,6 +2730,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_RISCV_V_GET_CONTROL: error = RISCV_V_GET_CONTROL(); break; + case PR_GET_SHADOW_STACK_STATUS: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = arch_get_shadow_stack_status(me, (unsigned long __user *) arg2); + break; + case PR_SET_SHADOW_STACK_STATUS: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = arch_set_shadow_stack_status(me, arg2); + break; default: error = -EINVAL; break;