From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-25.6 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F111C433FB for ; Fri, 17 Jul 2020 11:05:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 112DF207E8 for ; Fri, 17 Jul 2020 11:05:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="AYM85whJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726898AbgGQLFr (ORCPT ); Fri, 17 Jul 2020 07:05:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725932AbgGQLFq (ORCPT ); Fri, 17 Jul 2020 07:05:46 -0400 Received: from mail-qt1-x84a.google.com (mail-qt1-x84a.google.com [IPv6:2607:f8b0:4864:20::84a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D296C061755 for ; Fri, 17 Jul 2020 04:05:46 -0700 (PDT) Received: by mail-qt1-x84a.google.com with SMTP id g6so6017590qtr.0 for ; Fri, 17 Jul 2020 04:05:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=A0A4NOvPoZRmlJEFnc9Ybsj+p4yV6Jy4v9LTBO5E+eA=; b=AYM85whJTz6inY0KMcuRYAS7KXI60FYmIz276Wvi+SMe86jSA2Rq15NzgwJa97wtjw 1HH2IWCSOow2frQmivVi+WzLT2si+Nca7QC8gmdE401YvfeCDVVsJPf5CInDWznKLiSR wNwMnKTXQ7Ody26ZhkedbBFk1/aFvyvB5yHNO62kKAKJAerk+czHfwNUjs7jHMil5kOh EfMuzjS9eQ3WmvKyjBEj1Bep+mtevIaNaR4J/9BLx39BU/3fpcvlGLgIIamy4lzsqwLP KqDMn/0IH25Wgm4qCBnT1E+TxQQBGrIErvwItzQXGQbgQvtoiXRupFDxs8JyT4FvAGLv fvPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=A0A4NOvPoZRmlJEFnc9Ybsj+p4yV6Jy4v9LTBO5E+eA=; b=X4CkK1BWnQ/7ApQnt92Oux00GTqJfpFpeu90Ioth2VArglhRzcStn22HdUAWLcuKqc Os0pfQdtqaa8wsImH5AF7759fhEZWR8WeyiFVbl8xn8GyenTtlsXwlliKwIZpH2j70wj Pb+foaeX1PLlJsSQUkHoYh0CdlZIodie2Lkqck3QvKqOcWZtbBE+GusttACLfW2JJQ44 zfo+ptNdnO15uqIsymMqx0kORFhcLkRGhj7sig/GbIx+O93T8xKkQ8h/IhBCRmEW8J3I BqN+l4ubUhypL8zXJQhNXbkDVKuvIlGCdZy2JY/EHmcioJit7WCRuw+GDnwq/1CjevU4 iqzQ== X-Gm-Message-State: AOAM533W3fEHwLew9P+d3IF1i4CKDzq6ytWymm7Fi7ple6yPYLpv3bXC M8GETIAvSgNZ2jE34VgnbstfGAPIFrlyyMMio3FIVqwuEGcubtwhuKnX/rnLHa38rjy2R0RnCYw gOQFctas+p7uZk1fFr3OeAHKHPHBRVfg1iqkGT7iLzpCcOjrSXTZqfiB/PW5I5xGDdHagY/1ZUc AlgfkWVZQD X-Google-Smtp-Source: ABdhPJzky/K/NrL9enQBz4tcUEjea0J/dph+N8T35L2N/epdExcIsfm6JYZH6vbTbPFKIwkzqMspMvKNaX4mJSt/AMk= X-Received: by 2002:a0c:9e4e:: with SMTP id z14mr8499045qve.71.1594983945511; Fri, 17 Jul 2020 04:05:45 -0700 (PDT) Date: Fri, 17 Jul 2020 04:05:32 -0700 Message-Id: <20200717110532.238533-1-asteinhauser@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.28.0.rc0.105.gf9edc3c819-goog Subject: [PATCH] PR_SPEC_DISABLE_NOEXEC support for arm64. From: Anthony Steinhauser To: linux-kernel@vger.kernel.org Cc: will@kernel.org, catalin.marinas@arm.com, Anthony Steinhauser Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For x64 it was already implemented in: https://github.com/torvalds/linux/commit/71368af The rationale is the same as for the x64 implementation. Signed-off-by: Anthony Steinhauser --- It's actively attempted by OpenJDK on arm64 CentOS and Fedora: https://git.centos.org/rpms/java-11-openjdk/blob/c8s/f/SOURCES/rh1566890-CVE_2018_3639-speculative_store_bypass.patch arch/arm64/include/asm/ssbd.h | 28 ++++++++++++++++++++++++++++ arch/arm64/kernel/process.c | 13 +++++++++++++ arch/arm64/kernel/ssbd.c | 34 +++++++++++++++++----------------- 3 files changed, 58 insertions(+), 17 deletions(-) create mode 100644 arch/arm64/include/asm/ssbd.h diff --git a/arch/arm64/include/asm/ssbd.h b/arch/arm64/include/asm/ssbd.h new file mode 100644 index 000000000000..68c716dc5811 --- /dev/null +++ b/arch/arm64/include/asm/ssbd.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2020 Google LLC. + */ +#ifndef __ASM_SSBD_H +#define __ASM_SSBD_H + +#include +#include +#include + +static inline void ssbd_ssbs_enable(struct task_struct *task) +{ + u64 val = is_compat_thread(task_thread_info(task)) ? + PSR_AA32_SSBS_BIT : PSR_SSBS_BIT; + + task_pt_regs(task)->pstate |= val; +} + +static inline void ssbd_ssbs_disable(struct task_struct *task) +{ + u64 val = is_compat_thread(task_thread_info(task)) ? + PSR_AA32_SSBS_BIT : PSR_SSBS_BIT; + + task_pt_regs(task)->pstate &= ~val; +} + +#endif /* __ASM_SSBD_H */ diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 6089638c7d43..ad3c67c86c4c 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -54,6 +54,7 @@ #include #include #include +#include #include #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) @@ -588,6 +589,18 @@ void arch_setup_new_exec(void) current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; ptrauth_thread_init_user(current); + + /* + * Don't inherit TIF_SSBD across exec boundary when + * PR_SPEC_DISABLE_NOEXEC is used. + */ + if (test_thread_flag(TIF_SSBD) && + task_spec_ssb_noexec(current)) { + clear_thread_flag(TIF_SSBD); + task_clear_spec_ssb_disable(current); + task_clear_spec_ssb_noexec(current); + ssbd_ssbs_enable(current); + } } #ifdef CONFIG_ARM64_TAGGED_ADDR_ABI diff --git a/arch/arm64/kernel/ssbd.c b/arch/arm64/kernel/ssbd.c index b26955f56750..e936b7ee700b 100644 --- a/arch/arm64/kernel/ssbd.c +++ b/arch/arm64/kernel/ssbd.c @@ -3,7 +3,6 @@ * Copyright (C) 2018 ARM Ltd, All Rights Reserved. */ -#include #include #include #include @@ -11,22 +10,7 @@ #include #include - -static void ssbd_ssbs_enable(struct task_struct *task) -{ - u64 val = is_compat_thread(task_thread_info(task)) ? - PSR_AA32_SSBS_BIT : PSR_SSBS_BIT; - - task_pt_regs(task)->pstate |= val; -} - -static void ssbd_ssbs_disable(struct task_struct *task) -{ - u64 val = is_compat_thread(task_thread_info(task)) ? - PSR_AA32_SSBS_BIT : PSR_SSBS_BIT; - - task_pt_regs(task)->pstate &= ~val; -} +#include /* * prctl interface for SSBD @@ -43,6 +27,7 @@ static int ssbd_prctl_set(struct task_struct *task, unsigned long ctrl) if (state == ARM64_SSBD_MITIGATED) { switch (ctrl) { case PR_SPEC_ENABLE: + case PR_SPEC_DISABLE_NOEXEC: return -EPERM; case PR_SPEC_DISABLE: case PR_SPEC_FORCE_DISABLE: @@ -62,6 +47,7 @@ static int ssbd_prctl_set(struct task_struct *task, unsigned long ctrl) task_spec_ssb_force_disable(task)) return -EPERM; task_clear_spec_ssb_disable(task); + task_clear_spec_ssb_noexec(task); clear_tsk_thread_flag(task, TIF_SSBD); ssbd_ssbs_enable(task); break; @@ -69,6 +55,7 @@ static int ssbd_prctl_set(struct task_struct *task, unsigned long ctrl) if (state == ARM64_SSBD_FORCE_DISABLE) return -EPERM; task_set_spec_ssb_disable(task); + task_clear_spec_ssb_noexec(task); set_tsk_thread_flag(task, TIF_SSBD); ssbd_ssbs_disable(task); break; @@ -76,10 +63,21 @@ static int ssbd_prctl_set(struct task_struct *task, unsigned long ctrl) if (state == ARM64_SSBD_FORCE_DISABLE) return -EPERM; task_set_spec_ssb_disable(task); + task_clear_spec_ssb_noexec(task); task_set_spec_ssb_force_disable(task); set_tsk_thread_flag(task, TIF_SSBD); ssbd_ssbs_disable(task); break; + case PR_SPEC_DISABLE_NOEXEC: + if (state == ARM64_SSBD_FORCE_ENABLE || + state == ARM64_SSBD_FORCE_DISABLE || + task_spec_ssb_force_disable(task)) + return -EPERM; + task_set_spec_ssb_disable(task); + task_set_spec_ssb_noexec(task); + set_tsk_thread_flag(task, TIF_SSBD); + ssbd_ssbs_disable(task); + break; default: return -ERANGE; } @@ -108,6 +106,8 @@ static int ssbd_prctl_get(struct task_struct *task) case ARM64_SSBD_KERNEL: if (task_spec_ssb_force_disable(task)) return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE; + if (task_spec_ssb_noexec(task)) + return PR_SPEC_PRCTL | PR_SPEC_DISABLE_NOEXEC; if (task_spec_ssb_disable(task)) return PR_SPEC_PRCTL | PR_SPEC_DISABLE; return PR_SPEC_PRCTL | PR_SPEC_ENABLE; -- 2.18.4