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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 0E5E0C43441 for ; Sat, 17 Nov 2018 02:27:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D39782075B for ; Sat, 17 Nov 2018 02:27:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D39782075B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731412AbeKQMms (ORCPT ); Sat, 17 Nov 2018 07:42:48 -0500 Received: from mga14.intel.com ([192.55.52.115]:45905 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731204AbeKQMmq (ORCPT ); Sat, 17 Nov 2018 07:42:46 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Nov 2018 18:27:51 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,242,1539673200"; d="scan'208";a="281852635" Received: from skl-02.jf.intel.com ([10.54.74.62]) by fmsmga006.fm.intel.com with ESMTP; 16 Nov 2018 18:27:50 -0800 From: Tim Chen To: Jiri Kosina , Thomas Gleixner Cc: Tim Chen , Tom Lendacky , Ingo Molnar , Peter Zijlstra , Josh Poimboeuf , Andrea Arcangeli , David Woodhouse , Andi Kleen , Dave Hansen , Casey Schaufler , Asit Mallick , Arjan van de Ven , Jon Masters , Waiman Long , linux-kernel@vger.kernel.org, x86@kernel.org Subject: [Patch v5 14/16] x86/speculation: Use STIBP to restrict speculation on non-dumpable task Date: Fri, 16 Nov 2018 17:53:57 -0800 Message-Id: X-Mailer: git-send-email 2.9.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a task changes its dumpability, arch_update_spec_ctrl_restriction() is called to place restriction on the task's speculative execution according to dumpability changes. Implements arch_update_spec_restriction() for x86. Use STIBP to restrict speculative execution when running a task set to non-dumpable, or clear the restriction if the task is set to dumpable. Signed-off-by: Tim Chen --- Documentation/admin-guide/kernel-parameters.txt | 3 ++- arch/x86/kernel/cpu/bugs.c | 21 +++++++++++++++++++-- 2 files changed, 21 insertions(+), 3 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 9c306e3..102f9a1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4221,7 +4221,8 @@ vulnerability. off - Unconditionally disable mitigations - lite - Protect tasks which have requested restricted + lite - Protect tasks which are marked non-dumpable + and tasks which have requested restricted indirect branch speculation via the PR_SET_SPECULATION_CTRL prctl(). strict - Protect all processes diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 8f5187e..e7f9334 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -152,7 +153,7 @@ static const char *spectre_v2_strings[] = { static const char *spectre_v2_app2app_strings[] = { [SPECTRE_V2_APP2APP_NONE] = "App-App Vulnerable", - [SPECTRE_V2_APP2APP_LITE] = "App-App Mitigation: Protect branch speculation restricted tasks", + [SPECTRE_V2_APP2APP_LITE] = "App-App Mitigation: Protect non-dumpable and branch speculation restricted tasks", [SPECTRE_V2_APP2APP_STRICT] = "App-App Mitigation: Full app to app attack protection", }; @@ -779,13 +780,29 @@ static void set_task_stibp(struct task_struct *tsk, bool stibp_on) if (stibp_on) update = !test_and_set_tsk_thread_flag(tsk, TIF_STIBP); - else + else if (!task_spec_indir_branch_disable(tsk)) update = test_and_clear_tsk_thread_flag(tsk, TIF_STIBP); if (tsk == current && update) speculation_ctrl_update_current(); } +int arch_update_spec_restriction(struct task_struct *task) +{ + if (!static_branch_unlikely(&spectre_v2_app_lite)) + return 0; + + if (!task->mm) + return -EINVAL; + + if (get_dumpable(task->mm) != SUID_DUMP_USER) + set_task_stibp(task, true); + else + set_task_stibp(task, false); + + return 0; +} + static int indir_branch_prctl_set(struct task_struct *task, unsigned long ctrl) { switch (ctrl) { -- 2.9.4