From patchwork Fri Sep 4 20:31:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 11758533 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 77B9813B1 for ; Fri, 4 Sep 2020 20:32:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66FD6208C7 for ; Fri, 4 Sep 2020 20:32:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728099AbgIDUcH (ORCPT ); Fri, 4 Sep 2020 16:32:07 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:42066 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727923AbgIDUcD (ORCPT ); Fri, 4 Sep 2020 16:32:03 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id F401129B03B From: Gabriel Krisman Bertazi To: luto@kernel.org, tglx@linutronix.de, keescook@chromium.org Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, willy@infradead.org, linux-kselftest@vger.kernel.org, shuah@kernel.org, Gabriel Krisman Bertazi , kernel@collabora.com Subject: [PATCH v6 2/9] kernel: entry: Support TIF_SYSCAL_INTERCEPT on common entry code Date: Fri, 4 Sep 2020 16:31:40 -0400 Message-Id: <20200904203147.2908430-3-krisman@collabora.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200904203147.2908430-1-krisman@collabora.com> References: <20200904203147.2908430-1-krisman@collabora.com> MIME-Version: 1.0 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Syscalls that use common entry code (x86 at the moment of this writing) need to have their defines updated inside this commit. This added a measureable overhead of 1ns to seccomp_benchmark selftests on a bare-metal AMD system. Signed-off-by: Gabriel Krisman Bertazi Acked-by: Christian Brauner --- arch/x86/include/asm/thread_info.h | 4 ++-- include/linux/entry-common.h | 6 +----- kernel/entry/common.c | 24 +++++++++++++++++++++--- 3 files changed, 24 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 267701ae3d86..cf723181e1f2 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -82,7 +82,7 @@ struct thread_info { #define TIF_SSBD 5 /* Speculative store bypass disable */ #define TIF_SYSCALL_EMU 6 /* syscall emulation active */ #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ -#define TIF_SECCOMP 8 /* secure computing */ +#define TIF_SYSCALL_INTERCEPT 8 /* Intercept system call */ #define TIF_SPEC_IB 9 /* Indirect branch speculation mitigation */ #define TIF_SPEC_FORCE_UPDATE 10 /* Force speculation MSR update in context switch */ #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ @@ -112,7 +112,7 @@ struct thread_info { #define _TIF_SSBD (1 << TIF_SSBD) #define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) -#define _TIF_SECCOMP (1 << TIF_SECCOMP) +#define _TIF_SYSCALL_INTERCEPT (1 << TIF_SYSCALL_INTERCEPT) #define _TIF_SPEC_IB (1 << TIF_SPEC_IB) #define _TIF_SPEC_FORCE_UPDATE (1 << TIF_SPEC_FORCE_UPDATE) #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index efebbffcd5cc..72ce9ca860c6 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -21,10 +21,6 @@ # define _TIF_SYSCALL_TRACEPOINT (0) #endif -#ifndef _TIF_SECCOMP -# define _TIF_SECCOMP (0) -#endif - #ifndef _TIF_SYSCALL_AUDIT # define _TIF_SYSCALL_AUDIT (0) #endif @@ -45,7 +41,7 @@ #endif #define SYSCALL_ENTER_WORK \ - (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \ + (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_INTERCEPT | \ _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_EMU | \ ARCH_SYSCALL_ENTER_WORK) diff --git a/kernel/entry/common.c b/kernel/entry/common.c index fcae019158ca..44fd089d59da 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -4,6 +4,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -41,6 +42,20 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall) } } +static inline long do_syscall_intercept(struct pt_regs *regs) +{ + int sysint_work = READ_ONCE(current->syscall_intercept); + int ret; + + if (sysint_work & SYSINT_SECCOMP) { + ret = __secure_computing(NULL); + if (ret == -1L) + return ret; + } + + return 0; +} + static long syscall_trace_enter(struct pt_regs *regs, long syscall, unsigned long ti_work) { @@ -53,9 +68,12 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall, return -1L; } - /* Do seccomp after ptrace, to catch any tracer changes. */ - if (ti_work & _TIF_SECCOMP) { - ret = __secure_computing(NULL); + /* + * Do syscall interception like seccomp after ptrace, to catch + * any tracer changes. + */ + if (ti_work & _TIF_SYSCALL_INTERCEPT) { + ret = do_syscall_intercept(regs); if (ret == -1L) return ret; }