From patchwork Tue Jul 10 22:26:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu-cheng Yu X-Patchwork-Id: 10518197 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E1989600CA for ; Tue, 10 Jul 2018 22:32:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D464A2623D for ; Tue, 10 Jul 2018 22:32:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C87C728F39; Tue, 10 Jul 2018 22:32:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=unavailable version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4D8F42623D for ; Tue, 10 Jul 2018 22:32:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 45E426B0279; Tue, 10 Jul 2018 18:31:21 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 3B1706B0278; Tue, 10 Jul 2018 18:31:21 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1DE176B0279; Tue, 10 Jul 2018 18:31:21 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id BE9256B0276 for ; Tue, 10 Jul 2018 18:31:20 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id t78-v6so14736454pfa.8 for ; Tue, 10 Jul 2018 15:31:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:date:message-id:in-reply-to:references; bh=qOc07Ioxq/VDhZtk/IEiVHMXAJXdM8fm5sNyZKNqiiA=; b=WcXD0nG5YxfJQSGntUzpq/8KuXe2t7wjfa9TemYzA1Cf/HmUmFd7T9CxQckKeW+ITi +Zf8L0Cs0P/0lsuEYsaiwJN4fpLI8S6WU/ka3BBFr+8rbD+Lwu5IgSlHzFwlJ/i/+pje xIrKZ0z9Ci6L3EM4BbWGvFWrzEJx6oupT+yOBjcjVk+ZSNCJGxaW1b18z1wg8MDCrgVh 1fZ8xzGnvNuwALZQFnM9p6z95/NOdnpAkYKBM31OEEPJdI005CFSu3GP4miBbESP1r0z dzcXCsmr0dkCXaNKhS/zvn+VfW2GNrgmIK5fTAEpCwo6vjgGFXrbPlaowhOIDmGIIdqR g2tA== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of yu-cheng.yu@intel.com designates 192.55.52.136 as permitted sender) smtp.mailfrom=yu-cheng.yu@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Gm-Message-State: APt69E0B5reTjYdWJz+JopyTkxzn0Qszg01+WrGMhp02QRJ1+P4Gwup4 m2VPWnpJ5odMSmwLpmr5VMtDiqE/V0hITfha/vhq7O/2uyxTuEB8EbXrDVpnzAnzCEaBpUOjJW7 UD7edoIpLlHtinEZBEntEnx/Dgh3X/B1hYyQoizgRU9lavcJfOyECdhev8pfUvJ9J/Q== X-Received: by 2002:a62:e18:: with SMTP id w24-v6mr27579518pfi.145.1531261880454; Tue, 10 Jul 2018 15:31:20 -0700 (PDT) X-Google-Smtp-Source: AAOMgpdtCvMdPhkQpg8inxPks5KmXc/nPBmvyOYOVEHeuIoAdosFJkogjhvT8WCcJv2xCqeImMit X-Received: by 2002:a62:e18:: with SMTP id w24-v6mr27579479pfi.145.1531261879563; Tue, 10 Jul 2018 15:31:19 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1531261879; cv=none; d=google.com; s=arc-20160816; b=XuSmZwwk/6uibe95Gm5qyRluY9MJRxKv/LUyP+oO3J97qMq9DI33Hpe661RzXk0Jup x7qhijTrwD/6JaII2QbFLQrkrxxuHVOL2HCE97jaZ3I5DAYrgpnJRPxqofBZE1LgfRsU dl+UPvSP5lA1MMhNI17PSkZY++sTRmPjlBVt/uTi0Agj+xZWw5Tv4YX3FB7o+yWE7yF4 an9qTdHuHdoHx4FbBFJQTRampsntCLsBmeQiS/tftsFS7NAygidrayamZAm6MjiSRp8/ M+o4y1ehOGgVeurSMaoBHpDvvQYL/7ondbjCR/2bj6lu7oXf7HGteLswsB23y7SNGwSD F17g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :arc-authentication-results; bh=qOc07Ioxq/VDhZtk/IEiVHMXAJXdM8fm5sNyZKNqiiA=; b=iVXNYCvAUl14oIMatCZyRIj6pXLY6+3fak7spVdFjIQDf6EcS+fDgFKhq13NfXjfGg QjjZreXBTM/bjsvSFxsxTXTPLeO0YiUENUQ60pMlcqeEPBsYJgI7yJPwCl+5cqsFbuOx qj7nb5WJgF0uAkApO9/6m2j0MJxD1/UatEA58/ag/3FtzcaiRSIj00Zk+2KlKEMtLqsK EGZWHs9KytDQj7kfTg2MYLWsuRWK4jLexuIqvpqv10SUrIYws9HS9vKmGn7N3uodeDO0 XqbQw1d8Ig+SpdDhRlXzlNe8O9w9n4lERczqToyXKv+msbsEpv0b54d8b6akP9JqN6Ul HcTQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of yu-cheng.yu@intel.com designates 192.55.52.136 as permitted sender) smtp.mailfrom=yu-cheng.yu@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: from mga12.intel.com (mga12.intel.com. [192.55.52.136]) by mx.google.com with ESMTPS id e6-v6si18699657pfa.217.2018.07.10.15.31.19 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 10 Jul 2018 15:31:19 -0700 (PDT) Received-SPF: pass (google.com: domain of yu-cheng.yu@intel.com designates 192.55.52.136 as permitted sender) client-ip=192.55.52.136; Authentication-Results: mx.google.com; spf=pass (google.com: domain of yu-cheng.yu@intel.com designates 192.55.52.136 as permitted sender) smtp.mailfrom=yu-cheng.yu@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Jul 2018 15:31:17 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,335,1526367600"; d="scan'208";a="70305462" Received: from 2b52.sc.intel.com ([143.183.136.52]) by fmsmga004.fm.intel.com with ESMTP; 10 Jul 2018 15:31:17 -0700 From: Yu-cheng Yu 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 , Cyrill Gorcunov , Dave Hansen , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , "Ravi V. Shankar" , Vedvyas Shanbhogue Cc: Yu-cheng Yu Subject: [RFC PATCH v2 26/27] x86/cet/shstk: Handle thread shadow stack Date: Tue, 10 Jul 2018 15:26:38 -0700 Message-Id: <20180710222639.8241-27-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180710222639.8241-1-yu-cheng.yu@intel.com> References: <20180710222639.8241-1-yu-cheng.yu@intel.com> 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: X-Virus-Scanned: ClamAV using ClamSMTP The shadow stack for clone/fork is handled as the following: (1) If ((clone_flags & (CLONE_VFORK | CLONE_VM)) == CLONE_VM), the kernel allocates (and frees on thread exit) a new SHSTK for the child. It is possible for the kernel to complete the clone syscall and set the child's SHSTK pointer to NULL and let the child thread allocate a SHSTK for itself. There are two issues in this approach: It is not compatible with existing code that does inline syscall and it cannot handle signals before the child can successfully allocate a SHSTK. (2) For (clone_flags & CLONE_VFORK), the child uses the existing SHSTK. (3) For all other cases, the SHSTK is copied/reused whenever the parent or the child does a call/ret. This patch handles cases (1) & (2). Case (3) is handled in the SHSTK page fault patches. Signed-off-by: Yu-cheng Yu --- arch/x86/include/asm/cet.h | 2 ++ arch/x86/include/asm/mmu_context.h | 3 +++ arch/x86/kernel/cet.c | 33 ++++++++++++++++++++++++++++++ arch/x86/kernel/process.c | 1 + arch/x86/kernel/process_64.c | 7 +++++++ 5 files changed, 46 insertions(+) diff --git a/arch/x86/include/asm/cet.h b/arch/x86/include/asm/cet.h index 71da2cccba16..d5737f3346f2 100644 --- a/arch/x86/include/asm/cet.h +++ b/arch/x86/include/asm/cet.h @@ -20,6 +20,7 @@ struct cet_status { #ifdef CONFIG_X86_INTEL_CET int cet_setup_shstk(void); +int cet_setup_thread_shstk(struct task_struct *p); void cet_disable_shstk(void); void cet_disable_free_shstk(struct task_struct *p); int cet_restore_signal(unsigned long ssp); @@ -29,6 +30,7 @@ int cet_setup_ibt_bitmap(void); void cet_disable_ibt(void); #else static inline int cet_setup_shstk(void) { return 0; } +static inline int cet_setup_thread_shstk(struct task_struct *p) { return 0; } static inline void cet_disable_shstk(void) {} static inline void cet_disable_free_shstk(struct task_struct *p) {} static inline int cet_restore_signal(unsigned long ssp) { return 0; } diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index bbc796eb0a3b..662755048598 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -13,6 +13,7 @@ #include #include #include +#include extern atomic64_t last_mm_ctx_id; @@ -228,6 +229,8 @@ do { \ #else #define deactivate_mm(tsk, mm) \ do { \ + if (!tsk->vfork_done) \ + cet_disable_free_shstk(tsk); \ load_gs_index(0); \ loadsegment(fs, 0); \ } while (0) diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c index 8bbd63e1a2ba..2a366a5ccf20 100644 --- a/arch/x86/kernel/cet.c +++ b/arch/x86/kernel/cet.c @@ -155,6 +155,39 @@ int cet_setup_shstk(void) return 0; } +int cet_setup_thread_shstk(struct task_struct *tsk) +{ + unsigned long addr, size; + struct cet_user_state *state; + + if (!current->thread.cet.shstk_enabled) + return 0; + + state = get_xsave_addr(&tsk->thread.fpu.state.xsave, + XFEATURE_MASK_SHSTK_USER); + + if (!state) + return -EINVAL; + + size = tsk->thread.cet.shstk_size; + if (size == 0) + size = in_ia32_syscall() ? SHSTK_SIZE_32:SHSTK_SIZE_64; + + addr = shstk_mmap(0, size); + + if (addr >= TASK_SIZE_MAX) { + tsk->thread.cet.shstk_base = 0; + tsk->thread.cet.shstk_size = 0; + tsk->thread.cet.shstk_enabled = 0; + return -ENOMEM; + } + + state->user_ssp = (u64)(addr + size - sizeof(u64)); + tsk->thread.cet.shstk_base = addr; + tsk->thread.cet.shstk_size = size; + return 0; +} + void cet_disable_shstk(void) { u64 r; diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 309ebb7f9d8d..43a57d284a22 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -127,6 +127,7 @@ void exit_thread(struct task_struct *tsk) free_vm86(t); + cet_disable_free_shstk(tsk); fpu__drop(fpu); } diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 12bb445fb98d..6e493b0bcedd 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -317,6 +317,13 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, if (sp) childregs->sp = sp; + /* Allocate a new shadow stack for pthread */ + if ((clone_flags & (CLONE_VFORK | CLONE_VM)) == CLONE_VM) { + err = cet_setup_thread_shstk(p); + if (err) + goto out; + } + err = -ENOMEM; if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) { p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,