From patchwork Sat Feb 18 21:14:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Edgecombe, Rick P" X-Patchwork-Id: 13145679 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 833ADC636CC for ; Sat, 18 Feb 2023 21:17:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F0AD9280028; Sat, 18 Feb 2023 16:16:34 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E9348280024; Sat, 18 Feb 2023 16:16:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D344B280028; Sat, 18 Feb 2023 16:16:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id C01DB280027 for ; Sat, 18 Feb 2023 16:16:34 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 9991B1A026D for ; Sat, 18 Feb 2023 21:16:34 +0000 (UTC) X-FDA: 80481671508.06.99A6CBC Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by imf12.hostedemail.com (Postfix) with ESMTP id 8EAD040009 for ; Sat, 18 Feb 2023 21:16:32 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=IZri8SJx; spf=pass (imf12.hostedemail.com: domain of rick.p.edgecombe@intel.com designates 192.55.52.43 as permitted sender) smtp.mailfrom=rick.p.edgecombe@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1676754992; 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=Sn4n7crmTxrbn/OIeUWT1Azd349YYKdcy9ub8HpHkYM=; b=YV2XQpHe6KNltqtJ2a6RdFHEOHrPi9Y33Z5GpjaBEjP739L9fE3PJHaQcfIMYzvRbmcE55 704pFh/DteMszGY0om/uwDEI51M2O9sqUwW1q9YVNnFjOfms0dycSx942+nwXymQLTvrKU rjtbPMe8G4g3El/t0tiu4icA5oJdufM= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=IZri8SJx; spf=pass (imf12.hostedemail.com: domain of rick.p.edgecombe@intel.com designates 192.55.52.43 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=1676754992; a=rsa-sha256; cv=none; b=4AX/jBBL/2FipRHGZ11XP7EcsbFeXK4QXPs+7ROCMxmsRNtDbtZ/c1AUTyT1fn1+9P5Erf YWG16PXYHPIlX387tglz/qZ231vp4OJJvaTuloOMTbpWvr21mwvJINA2exhzWXkqpGUX4N YxC6DUacmBLD86XMyenv3oW2TCn2J0c= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676754992; x=1708290992; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=PfOj46FKnOWR1PiqFiy1gLNlGQ5AfxHeduPbiAD9rSI=; b=IZri8SJxpcesIFXQ6MFFJCOnypJDXJ4/2EMluxarXMH8kOzi0SSi8Nzg eXT7Wu9cs0QMRkHvJfoCrrJMb84+aLNLBXoAlJIwgtIp8UBMm2W/YyIwS yVCenx/o1iGySWf1N6HtIGDZYFOCRRKWDBYJnB7XIWOoQdM4AGSlb3Bm7 wNmxTqUgxyliKmPsjuTPW8lXGNm7w2fhqVcy+Og/UfddPJTjjsfr7GRR4 I4hA7j5IOvDlw8KOC1+5HzACv+RmKl8wxrv6kouq06Ngyxfd4/zE4BAJJ +TJSkYl/ySZIZRSjsgkvoHJ+UOy+S6xy7E2vlSi3XjAnodc9OkBrW5BWm Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10625"; a="418427960" X-IronPort-AV: E=Sophos;i="5.97,309,1669104000"; d="scan'208";a="418427960" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Feb 2023 13:16:30 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10625"; a="664241764" X-IronPort-AV: E=Sophos;i="5.97,309,1669104000"; d="scan'208";a="664241764" Received: from adityava-mobl1.amr.corp.intel.com (HELO rpedgeco-desk.amr.corp.intel.com) ([10.209.80.223]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Feb 2023 13:16:29 -0800 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 , 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, Andrew.Cooper3@citrix.com, christina.schimpe@intel.com, david@redhat.com, debug@rivosinc.com Cc: rick.p.edgecombe@intel.com, Mike Rapoport Subject: [PATCH v6 40/41] x86/shstk: Add ARCH_SHSTK_UNLOCK Date: Sat, 18 Feb 2023 13:14:32 -0800 Message-Id: <20230218211433.26859-41-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230218211433.26859-1-rick.p.edgecombe@intel.com> References: <20230218211433.26859-1-rick.p.edgecombe@intel.com> X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: gtydbb9rnmtbg5ryo55z8x3dxcr7nia3 X-Rspamd-Queue-Id: 8EAD040009 X-HE-Tag: 1676754992-9105 X-HE-Meta: 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 s4gtlnIS Jy8aTc6l/3IU8RCoZGEhZ620dkd7SywApJX0RUa7U1EAUu4M3+aN1F0L6rMp6carWN4+ejGwrEYu6jMrHhhTvqLUUON9J7To/+PPtbAWWsdFdYMI1eqaJRZX8I90f6iRHyFNmXRpKuKcVyPjjdqVYLzOibmof5d4Nf8W2WXV94QoRKgp8wQSkNXBFobwaWZY80hDedAVCQAuRgkW/jHHhQH4BVzymuBJTaU07qMXvFMf9Is7FfzvZMWax1QdK/B+c6Znh3lOcywnVJIobD/41ivMRNdAtqJDn7webHtpwzyd2C2Ptkmn4mQKXiURTNqzhgiUr+qpl8s1DE6fZlbXhA0GtS1PR01Ta5ph4ieeUF38YJ+Q= 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 shadow stack operations, but restrict it being called by the ptrace arch_pctl() interface. Reviewed-by: Kees Cook 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 --- v4: - Add to docs that it is ptrace only. - Remove "CET" references v3: - Depend on CONFIG_CHECKPOINT_RESTORE (Kees) --- Documentation/x86/shstk.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/shstk.rst b/Documentation/x86/shstk.rst index f2e6f323cf68..e8ed5fc0f7ae 100644 --- a/Documentation/x86/shstk.rst +++ b/Documentation/x86/shstk.rst @@ -73,6 +73,10 @@ arch_prctl(ARCH_SHSTK_LOCK, unsigned long 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_SHSTK_UNLOCK, unsigned long features) + Unlock features. 'features' is a mask of all features to unlock. All + bits set are processed, unset bits are ignored. Only works via ptrace. + The return values are as follows. 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 e31495668056..200efbbe5809 100644 --- a/arch/x86/include/uapi/asm/prctl.h +++ b/arch/x86/include/uapi/asm/prctl.h @@ -25,6 +25,7 @@ #define ARCH_SHSTK_ENABLE 0x5001 #define ARCH_SHSTK_DISABLE 0x5002 #define ARCH_SHSTK_LOCK 0x5003 +#define ARCH_SHSTK_UNLOCK 0x5004 /* ARCH_SHSTK_ features bits */ #define ARCH_SHSTK_SHSTK (1ULL << 0) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 71094c8a305f..d368854fa9c4 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_SHSTK_ENABLE: case ARCH_SHSTK_DISABLE: case ARCH_SHSTK_LOCK: + case ARCH_SHSTK_UNLOCK: return shstk_prctl(task, option, arg2); default: ret = -EINVAL; diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c index 2faf9b45ac72..3197ff824809 100644 --- a/arch/x86/kernel/shstk.c +++ b/arch/x86/kernel/shstk.c @@ -451,9 +451,14 @@ long shstk_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_SHSTK_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)