From patchwork Wed Feb 17 22:27:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu-cheng Yu X-Patchwork-Id: 12092511 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 7F9CFC433E0 for ; Wed, 17 Feb 2021 22:28:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 214C064E33 for ; Wed, 17 Feb 2021 22:28:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 214C064E33 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6D6356B0073; Wed, 17 Feb 2021 17:28:01 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6600E6B0074; Wed, 17 Feb 2021 17:28:01 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 303886B0073; Wed, 17 Feb 2021 17:28:01 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0054.hostedemail.com [216.40.44.54]) by kanga.kvack.org (Postfix) with ESMTP id EA8EA6B0075 for ; Wed, 17 Feb 2021 17:28:00 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id B6D118249980 for ; Wed, 17 Feb 2021 22:28:00 +0000 (UTC) X-FDA: 77829198720.22.sink97_380784227650 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin22.hostedemail.com (Postfix) with ESMTP id 98A6E18038E60 for ; Wed, 17 Feb 2021 22:28:00 +0000 (UTC) X-HE-Tag: sink97_380784227650 X-Filterd-Recvd-Size: 8079 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Wed, 17 Feb 2021 22:27:59 +0000 (UTC) IronPort-SDR: mb0Aqu+zxTw8a0f4QnL+aFyT6/KsXTl71OmPuqBddj+W9CmjryVzSEABcyZFE3RbC+dCl1+jhe Psdt2d3KWG0Q== X-IronPort-AV: E=McAfee;i="6000,8403,9898"; a="170993983" X-IronPort-AV: E=Sophos;i="5.81,185,1610438400"; d="scan'208";a="170993983" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2021 14:27:56 -0800 IronPort-SDR: c2+mSaWb0KR0wfAwIEm20Wc+TTy9xS3ET+XWHcJvirCRUiuv0FDn+U9Iqygov+shBSBwrQssaY DtZZIJdCt9FA== X-IronPort-AV: E=Sophos;i="5.81,185,1610438400"; d="scan'208";a="400172604" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2021 14:27:56 -0800 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 , 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 , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang Cc: Yu-cheng Yu , Michael Kerrisk Subject: [PATCH v21 06/26] x86/cet: Add control-protection fault handler Date: Wed, 17 Feb 2021 14:27:10 -0800 Message-Id: <20210217222730.15819-7-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210217222730.15819-1-yu-cheng.yu@intel.com> References: <20210217222730.15819-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 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: A control-protection fault is triggered when a control-flow transfer attempt violates Shadow Stack or Indirect Branch Tracking constraints. For example, the return address for a RET instruction differs from the copy on the shadow stack; or an indirect JMP instruction, without the NOTRACK prefix, arrives at a non-ENDBR opcode. The control-protection fault handler works in a similar way as the general protection fault handler. It provides the si_code SEGV_CPERR to the signal handler. Signed-off-by: Yu-cheng Yu Reviewed-by: Kees Cook Cc: Michael Kerrisk --- arch/x86/include/asm/idtentry.h | 4 ++ arch/x86/kernel/idt.c | 4 ++ arch/x86/kernel/signal_compat.c | 2 +- arch/x86/kernel/traps.c | 63 ++++++++++++++++++++++++++++++ include/uapi/asm-generic/siginfo.h | 3 +- 5 files changed, 74 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index f656aabd1545..ff4b3bf634da 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -574,6 +574,10 @@ DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_SS, exc_stack_segment); DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_GP, exc_general_protection); DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_AC, exc_alignment_check); +#ifdef CONFIG_X86_CET +DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_CP, exc_control_protection); +#endif + /* Raw exception entries which need extra work */ DECLARE_IDTENTRY_RAW(X86_TRAP_UD, exc_invalid_op); DECLARE_IDTENTRY_RAW(X86_TRAP_BP, exc_int3); diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index ee1a283f8e96..e8166d9bbb10 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -105,6 +105,10 @@ static const __initconst struct idt_data def_idts[] = { #elif defined(CONFIG_X86_32) SYSG(IA32_SYSCALL_VECTOR, entry_INT80_32), #endif + +#ifdef CONFIG_X86_CET + INTG(X86_TRAP_CP, asm_exc_control_protection), +#endif }; /* diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c index a5330ff498f0..dd92490b1e7f 100644 --- a/arch/x86/kernel/signal_compat.c +++ b/arch/x86/kernel/signal_compat.c @@ -27,7 +27,7 @@ static inline void signal_compat_build_tests(void) */ BUILD_BUG_ON(NSIGILL != 11); BUILD_BUG_ON(NSIGFPE != 15); - BUILD_BUG_ON(NSIGSEGV != 9); + BUILD_BUG_ON(NSIGSEGV != 10); BUILD_BUG_ON(NSIGBUS != 5); BUILD_BUG_ON(NSIGTRAP != 5); BUILD_BUG_ON(NSIGCHLD != 6); diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 7f5aec758f0e..8c7fa91a57c9 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -39,6 +39,7 @@ #include #include #include +#include #include #include @@ -606,6 +607,68 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection) cond_local_irq_disable(regs); } +#ifdef CONFIG_X86_CET +static const char * const control_protection_err[] = { + "unknown", + "near-ret", + "far-ret/iret", + "endbranch", + "rstorssp", + "setssbsy", + "unknown", +}; + +/* + * When a control protection exception occurs, send a signal to the responsible + * application. Currently, control protection is only enabled for user mode. + * This exception should not come from kernel mode. + */ +DEFINE_IDTENTRY_ERRORCODE(exc_control_protection) +{ + static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + struct task_struct *tsk; + + if (!user_mode(regs)) { + pr_emerg("PANIC: unexpected kernel control protection fault\n"); + die("kernel control protection fault", regs, error_code); + panic("Machine halted."); + } + + cond_local_irq_enable(regs); + + if (!boot_cpu_has(X86_FEATURE_CET)) + WARN_ONCE(1, "Control protection fault with CET support disabled\n"); + + tsk = current; + tsk->thread.error_code = error_code; + tsk->thread.trap_nr = X86_TRAP_CP; + + /* + * Ratelimit to prevent log spamming. + */ + if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && + __ratelimit(&rs)) { + unsigned long ssp; + int err; + + err = array_index_nospec(error_code, ARRAY_SIZE(control_protection_err)); + + rdmsrl(MSR_IA32_PL3_SSP, ssp); + pr_emerg("%s[%d] control protection ip:%lx sp:%lx ssp:%lx error:%lx(%s)", + tsk->comm, task_pid_nr(tsk), + regs->ip, regs->sp, ssp, error_code, + control_protection_err[err]); + print_vma_addr(KERN_CONT " in ", regs->ip); + pr_cont("\n"); + } + + force_sig_fault(SIGSEGV, SEGV_CPERR, + (void __user *)uprobe_get_trap_addr(regs)); + cond_local_irq_disable(regs); +} +#endif + static bool do_int3(struct pt_regs *regs) { int res; diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h index d2597000407a..1c2ea91284a0 100644 --- a/include/uapi/asm-generic/siginfo.h +++ b/include/uapi/asm-generic/siginfo.h @@ -231,7 +231,8 @@ typedef struct siginfo { #define SEGV_ADIPERR 7 /* Precise MCD exception */ #define SEGV_MTEAERR 8 /* Asynchronous ARM MTE error */ #define SEGV_MTESERR 9 /* Synchronous ARM MTE exception */ -#define NSIGSEGV 9 +#define SEGV_CPERR 10 /* Control protection fault */ +#define NSIGSEGV 10 /* * SIGBUS si_codes