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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14FEEC7618A for ; Sun, 19 Mar 2023 00:23:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230384AbjCSAXJ (ORCPT ); Sat, 18 Mar 2023 20:23:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230305AbjCSAWc (ORCPT ); Sat, 18 Mar 2023 20:22:32 -0400 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7FFB129E1F; Sat, 18 Mar 2023 17:20:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1679185217; x=1710721217; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=SZKEydO4/dqCRXo76Ax/xNMIP87QKuRYX84LlmCxycM=; b=W0+umJOkovW1kwBVkA3izhrfi/atcAsG43NBfyO4iSuWoYYa4D1TPV+y 0dchiP3KysTylwTDfqcq934Rcz6o3kwkCb0C4jr1pghW/KGMBmlh7OLvZ XGQuY1KE7Uvn+ZXO2YMQ9Ff8cRMX4WpxacOjxqaLNEItOxRYsTVr1kQo8 TTc9vEJbTa/3qtwFC4CPqVzjJIfyxdacwfxjKY6awCuZpmlJk5EQ5ituk V8I5JShJIO8n4S1PJzaFJSTBzuvZpBk0JsY3GkvG8LAcbzov76WsUbDpQ HcnZffIcX4xh+gJOVW1RQy8LvolPAfUpc5d7hToQ+iMUGwTzd7gUMcq4r g==; X-IronPort-AV: E=McAfee;i="6600,9927,10653"; a="338491512" X-IronPort-AV: E=Sophos;i="5.98,272,1673942400"; d="scan'208";a="338491512" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2023 17:16:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10653"; a="749672980" X-IronPort-AV: E=Sophos;i="5.98,272,1673942400"; d="scan'208";a="749672980" Received: from bmahatwo-mobl1.gar.corp.intel.com (HELO rpedgeco-desk.amr.corp.intel.com) ([10.135.34.5]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2023 17:16:51 -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 , 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, szabolcs.nagy@arm.com Cc: rick.p.edgecombe@intel.com Subject: [PATCH v8 35/40] x86: Expose thread features in /proc/$PID/status Date: Sat, 18 Mar 2023 17:15:30 -0700 Message-Id: <20230319001535.23210-36-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230319001535.23210-1-rick.p.edgecombe@intel.com> References: <20230319001535.23210-1-rick.p.edgecombe@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Applications and loaders can have logic to decide whether to enable shadow stack. They usually don't report whether shadow stack has been enabled or not, so there is no way to verify whether an application actually is protected by shadow stack. Add two lines in /proc/$PID/status to report enabled and locked features. Since, this involves referring to arch specific defines in asm/prctl.h, implement an arch breakout to emit the feature lines. [Switched to CET, added to commit log] Co-developed-by: Kirill A. Shutemov Signed-off-by: Kirill A. Shutemov Signed-off-by: Rick Edgecombe Reviewed-by: Kees Cook Acked-by: Mike Rapoport (IBM) Tested-by: Pengfei Xu Tested-by: John Allen Tested-by: Kees Cook --- v4: - Remove "CET" references v3: - Move to /proc/pid/status (Kees) v2: - New patch --- arch/x86/kernel/cpu/proc.c | 23 +++++++++++++++++++++++ fs/proc/array.c | 6 ++++++ include/linux/proc_fs.h | 2 ++ 3 files changed, 31 insertions(+) diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c index 099b6f0d96bd..31c0e68f6227 100644 --- a/arch/x86/kernel/cpu/proc.c +++ b/arch/x86/kernel/cpu/proc.c @@ -4,6 +4,8 @@ #include #include #include +#include +#include #include "cpu.h" @@ -175,3 +177,24 @@ const struct seq_operations cpuinfo_op = { .stop = c_stop, .show = show_cpuinfo, }; + +#ifdef CONFIG_X86_USER_SHADOW_STACK +static void dump_x86_features(struct seq_file *m, unsigned long features) +{ + if (features & ARCH_SHSTK_SHSTK) + seq_puts(m, "shstk "); + if (features & ARCH_SHSTK_WRSS) + seq_puts(m, "wrss "); +} + +void arch_proc_pid_thread_features(struct seq_file *m, struct task_struct *task) +{ + seq_puts(m, "x86_Thread_features:\t"); + dump_x86_features(m, task->thread.features); + seq_putc(m, '\n'); + + seq_puts(m, "x86_Thread_features_locked:\t"); + dump_x86_features(m, task->thread.features_locked); + seq_putc(m, '\n'); +} +#endif /* CONFIG_X86_USER_SHADOW_STACK */ diff --git a/fs/proc/array.c b/fs/proc/array.c index 9b0315d34c58..3e1a33dcd0d0 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -423,6 +423,11 @@ static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm) seq_printf(m, "THP_enabled:\t%d\n", thp_enabled); } +__weak void arch_proc_pid_thread_features(struct seq_file *m, + struct task_struct *task) +{ +} + int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { @@ -446,6 +451,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, task_cpus_allowed(m, task); cpuset_task_status_allowed(m, task); task_context_switch_counts(m, task); + arch_proc_pid_thread_features(m, task); return 0; } diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 0260f5ea98fe..80ff8e533cbd 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -158,6 +158,8 @@ int proc_pid_arch_status(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task); #endif /* CONFIG_PROC_PID_ARCH_STATUS */ +void arch_proc_pid_thread_features(struct seq_file *m, struct task_struct *task); + #else /* CONFIG_PROC_FS */ static inline void proc_root_init(void) -- 2.17.1