From patchwork Fri Nov 4 22:36:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Edgecombe, Rick P" X-Patchwork-Id: 13032674 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B890C4167D for ; Fri, 4 Nov 2022 22:40:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8D3F98E001E; Fri, 4 Nov 2022 18:39:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6FCE08E0018; Fri, 4 Nov 2022 18:39:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3C4B78E001E; Fri, 4 Nov 2022 18:39:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 221288E0018 for ; Fri, 4 Nov 2022 18:39:56 -0400 (EDT) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id E847AC09E6 for ; Fri, 4 Nov 2022 22:39:55 +0000 (UTC) X-FDA: 80097228750.16.0860C4F Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by imf17.hostedemail.com (Postfix) with ESMTP id 66E9040002 for ; Fri, 4 Nov 2022 22:39:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1667601595; x=1699137595; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=mTDZ+f4KdYSqV9q+619GLZ5q/2YYY0xPkbFAnS8RyTs=; b=TQX62gfdbqUSoPkhiC4j1qlZHfdBl9oAJD7Z2+46/VNcwEpSG60FrNsu raU1tqOBGgqfL5Kf2yUGYo0zG5l6Lf8cBuOKFhSty+tB9/ycuov3gkfPf OKy+NRpHNF9C6UoZjzcrarFxvWV0mgolsfCbZewJJqBfclkCQcrWeEgnd Qe4IzsFiRoGkrT11H3m1g7p/DeICMui8b42YLO3coyog8X4OczVEjQxTW 0p3co61FstcXYmv6TFRbBGqFCOyn1kjDZVummZcO82lH3+mByn4hX4n0r KX9apKwSXwZcEjXy5jmDovtEu+j90mNBXDQnfhOEOXZQjfPPMGYBodYYq A==; X-IronPort-AV: E=McAfee;i="6500,9779,10521"; a="297559735" X-IronPort-AV: E=Sophos;i="5.96,138,1665471600"; d="scan'208";a="297559735" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Nov 2022 15:39:55 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10521"; a="668514181" X-IronPort-AV: E=Sophos;i="5.96,138,1665471600"; d="scan'208";a="668514181" Received: from adhjerms-mobl1.amr.corp.intel.com (HELO rpedgeco-desk.amr.corp.intel.com) ([10.212.227.68]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Nov 2022 15:39:54 -0700 From: Rick Edgecombe To: x86@kernel.org, "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V . Shankar" , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org Cc: rick.p.edgecombe@intel.com, Mike Rapoport Subject: [PATCH v3 36/37] x86/cet/shstk: Add ARCH_CET_UNLOCK Date: Fri, 4 Nov 2022 15:36:03 -0700 Message-Id: <20221104223604.29615-37-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20221104223604.29615-1-rick.p.edgecombe@intel.com> References: <20221104223604.29615-1-rick.p.edgecombe@intel.com> ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1667601595; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references:dkim-signature; bh=4DbhJGL2YfsIhJmqdbV0qT0hHBtBUjxUx75J/ln81gM=; b=rHfIbgs2G0n/PfBCihd1T77IK3dOtSuy55hllsN8d0ybCl1cq/MH7EjHWjoHyZUMdDqmKP VvaoOyaWeC/qD4UoHX1CrTO3crjmWFfMMzXax/SCgO+4shcEHpW9Yi2G+/tYXTARTGFmlZ fTrmlOaKkOS8gijlfSJzO8TPnUR0smw= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=TQX62gfd; spf=pass (imf17.hostedemail.com: domain of rick.p.edgecombe@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=rick.p.edgecombe@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1667601595; a=rsa-sha256; cv=none; b=06lenLBPZH1GM/dOKOulgQ2gyY6mU4b25aWiIWPJXkH+rIxFyrCR2JlPe4Y61myYUxNpbR V/SSbMyjKOeCA4mL7czGKKCw4csz6dsfZ4NGOcUee7J7AjmmT0ULRkdvdhA+qHn3vHRBe0 +z/WbP3zk4Ypaw6Iwh7NXPxDy43MW+E= Authentication-Results: imf17.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=TQX62gfd; spf=pass (imf17.hostedemail.com: domain of rick.p.edgecombe@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=rick.p.edgecombe@intel.com; dmarc=pass (policy=none) header.from=intel.com X-Stat-Signature: 8kh815pkorx38b8eghp976wtx6zipms4 X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 66E9040002 X-HE-Tag: 1667601595-407351 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Mike Rapoport Userspace loaders may lock features before a CRIU restore operation has the chance to set them to whatever state is required by the process being restored. Allow a way for CRIU to unlock features. Add it as an arch_prctl() like the other CET operations, but restrict it being called by the ptrace arch_pctl() interface. Tested-by: Pengfei Xu Tested-by: John Allen Signed-off-by: Mike Rapoport [Merged into recent API changes, added commit log and docs] Signed-off-by: Rick Edgecombe --- v3: - Depend on CONFIG_CHECKPOINT_RESTORE (Kees) Documentation/x86/cet.rst | 4 ++++ arch/x86/include/uapi/asm/prctl.h | 1 + arch/x86/kernel/process_64.c | 1 + arch/x86/kernel/shstk.c | 9 +++++++-- 4 files changed, 13 insertions(+), 2 deletions(-) diff --git a/Documentation/x86/cet.rst b/Documentation/x86/cet.rst index b56811566531..f69cafb1feff 100644 --- a/Documentation/x86/cet.rst +++ b/Documentation/x86/cet.rst @@ -66,6 +66,10 @@ arch_prctl(ARCH_CET_LOCK, unsigned int features) are ignored. The mask is ORed with the existing value. So any feature bits set here cannot be enabled or disabled afterwards. +arch_prctl(ARCH_CET_UNLOCK, unsigned int features) + Unlock features. 'features' is a mask of all features to unlock. All + bits set are processed, unset bits are ignored. + The return values are as following: On success, return 0. On error, errno can be:: diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h index 5f1d3181e4a1..0c37fd0ad8d9 100644 --- a/arch/x86/include/uapi/asm/prctl.h +++ b/arch/x86/include/uapi/asm/prctl.h @@ -25,6 +25,7 @@ #define ARCH_CET_ENABLE 0x5001 #define ARCH_CET_DISABLE 0x5002 #define ARCH_CET_LOCK 0x5003 +#define ARCH_CET_UNLOCK 0x5004 /* ARCH_CET_ features bits */ #define CET_SHSTK (1ULL << 0) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 17fec059317c..03bc16c9cc19 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -835,6 +835,7 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2) case ARCH_CET_ENABLE: case ARCH_CET_DISABLE: case ARCH_CET_LOCK: + case ARCH_CET_UNLOCK: return cet_prctl(task, option, arg2); default: ret = -EINVAL; diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c index 71620b77a654..bed7032d35f2 100644 --- a/arch/x86/kernel/shstk.c +++ b/arch/x86/kernel/shstk.c @@ -450,9 +450,14 @@ long cet_prctl(struct task_struct *task, int option, unsigned long features) return 0; } - /* Don't allow via ptrace */ - if (task != current) + /* Only allow via ptrace */ + if (task != current) { + if (option == ARCH_CET_UNLOCK && IS_ENABLED(CONFIG_CHECKPOINT_RESTORE)) { + task->thread.features_locked &= ~features; + return 0; + } return -EINVAL; + } /* Do not allow to change locked features */ if (features & task->thread.features_locked)