From patchwork Tue Mar 9 16:08:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: thermal-bot for Julien Panis X-Patchwork-Id: 396581 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=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS 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 929D6C433E0 for ; Tue, 9 Mar 2021 16:09:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B55064FE2 for ; Tue, 9 Mar 2021 16:09:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232009AbhCIQIk (ORCPT ); Tue, 9 Mar 2021 11:08:40 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:53936 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232100AbhCIQIO (ORCPT ); Tue, 9 Mar 2021 11:08:14 -0500 Date: Tue, 09 Mar 2021 16:08:12 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1615306093; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=0CLFxvYtbnQu30o06lG6/QY8MyBjV65kC6WDtbUgXPo=; b=r07hMu6xjNSdIT2Rybqemaz8oXygEsw1X8cT+chYuvr56UjQoJdwUH2rTpa7fGo2qSBhWq KMw4EMO1J+RSKtpaJWbGYWgjFxf/uvzN48VMCj0xs8+LGU2xAggNENm5SwQgTV8kuwjRui 07piqW4nqSVjtOCQMEFr2Rmzu4kRb4rU+Q9h+8priNFVZTR3Ncjsk7sqg+9/Zsv5iOT9DZ bKySXTqy/gi23RC9rsCOsM+3gVq3Tl8/fsf2sEEqLQacUufn0iWwccBsg8M+aS6DmX4Fsk 3IfOfrll5vxT2VIKkzbZW/hTbXlkbUqYWSTWQJ8FX/FPMk5dr0YMgCN25UlfRQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1615306093; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=0CLFxvYtbnQu30o06lG6/QY8MyBjV65kC6WDtbUgXPo=; b=spQel0pkrdh8jpdoDSf2Cn1TnXG/mXaK+Wb6IsQfDRka4XwSLqLs782n3QMKDxPdt2ZAWr G/+meEIPeV+DBiCg== From: "tip-bot2 for Joerg Roedel" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] x86/sev-es: Introduce ip_within_syscall_gap() helper Cc: Joerg Roedel , Borislav Petkov , stable@vger.kernel.org, #@tip-bot2.tec.linutronix.de, 5.10+@tip-bot2.tec.linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210303141716.29223-2-joro@8bytes.org> References: <20210303141716.29223-2-joro@8bytes.org> MIME-Version: 1.0 Message-ID: <161530609259.398.2946836058294820769.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 78a81d88f60ba773cbe890205e1ee67f00502948 Gitweb: https://git.kernel.org/tip/78a81d88f60ba773cbe890205e1ee67f00502948 Author: Joerg Roedel AuthorDate: Wed, 03 Mar 2021 15:17:12 +01:00 Committer: Borislav Petkov CommitterDate: Mon, 08 Mar 2021 14:22:17 +01:00 x86/sev-es: Introduce ip_within_syscall_gap() helper Introduce a helper to check whether an exception came from the syscall gap and use it in the SEV-ES code. Extend the check to also cover the compatibility SYSCALL entry path. Fixes: 315562c9af3d5 ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler") Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Cc: stable@vger.kernel.org # 5.10+ Link: https://lkml.kernel.org/r/20210303141716.29223-2-joro@8bytes.org --- arch/x86/entry/entry_64_compat.S | 2 ++ arch/x86/include/asm/proto.h | 1 + arch/x86/include/asm/ptrace.h | 15 +++++++++++++++ arch/x86/kernel/traps.c | 3 +-- 4 files changed, 19 insertions(+), 2 deletions(-) diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 541fdaf..0051cf5 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -210,6 +210,8 @@ SYM_CODE_START(entry_SYSCALL_compat) /* Switch to the kernel stack */ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp +SYM_INNER_LABEL(entry_SYSCALL_compat_safe_stack, SYM_L_GLOBAL) + /* Construct struct pt_regs on stack */ pushq $__USER32_DS /* pt_regs->ss */ pushq %r8 /* pt_regs->sp */ diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h index 2c35f1c..b6a9d51 100644 --- a/arch/x86/include/asm/proto.h +++ b/arch/x86/include/asm/proto.h @@ -25,6 +25,7 @@ void __end_SYSENTER_singlestep_region(void); void entry_SYSENTER_compat(void); void __end_entry_SYSENTER_compat(void); void entry_SYSCALL_compat(void); +void entry_SYSCALL_compat_safe_stack(void); void entry_INT80_compat(void); #ifdef CONFIG_XEN_PV void xen_entry_INT80_compat(void); diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index d8324a2..409f661 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -94,6 +94,8 @@ struct pt_regs { #include #endif +#include + struct cpuinfo_x86; struct task_struct; @@ -175,6 +177,19 @@ static inline bool any_64bit_mode(struct pt_regs *regs) #ifdef CONFIG_X86_64 #define current_user_stack_pointer() current_pt_regs()->sp #define compat_user_stack_pointer() current_pt_regs()->sp + +static inline bool ip_within_syscall_gap(struct pt_regs *regs) +{ + bool ret = (regs->ip >= (unsigned long)entry_SYSCALL_64 && + regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack); + +#ifdef CONFIG_IA32_EMULATION + ret = ret || (regs->ip >= (unsigned long)entry_SYSCALL_compat && + regs->ip < (unsigned long)entry_SYSCALL_compat_safe_stack); +#endif + + return ret; +} #endif static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 7f5aec7..ac1874a 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -694,8 +694,7 @@ asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *r * In the SYSCALL entry path the RSP value comes from user-space - don't * trust it and switch to the current kernel stack */ - if (regs->ip >= (unsigned long)entry_SYSCALL_64 && - regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack) { + if (ip_within_syscall_gap(regs)) { sp = this_cpu_read(cpu_current_top_of_stack); goto sync; }