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,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 85E36C282CE for ; Mon, 11 Feb 2019 17:59:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D2C821B18 for ; Mon, 11 Feb 2019 17:59:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732279AbfBKR7w (ORCPT ); Mon, 11 Feb 2019 12:59:52 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:55090 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731153AbfBKR7t (ORCPT ); Mon, 11 Feb 2019 12:59:49 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9C8DBEBD; Mon, 11 Feb 2019 09:59:48 -0800 (PST) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 22B2D3F675; Mon, 11 Feb 2019 09:59:46 -0800 (PST) From: Will Deacon To: linux-kernel@vger.kernel.org Cc: Will Deacon , Kees Cook , Jann Horn , Andrew Morton , Matthew Wilcox , Michal Hocko , Peter Zijlstra Subject: [RFC PATCH 4/4] arm64: Check user stack pointer on syscall entry Date: Mon, 11 Feb 2019 17:59:35 +0000 Message-Id: <20190211175935.4602-5-will.deacon@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190211175935.4602-1-will.deacon@arm.com> References: <20190211175935.4602-1-will.deacon@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow the user stack pointer value to be checked on system call entry and deliver a SIGSEGV if the check does not pass. Cc: Kees Cook Cc: Jann Horn Cc: Andrew Morton Cc: Matthew Wilcox Cc: Michal Hocko Cc: Peter Zijlstra Signed-off-by: Will Deacon --- arch/arm64/Kconfig | 1 + arch/arm64/kernel/syscall.c | 4 ++++ 2 files changed, 5 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index a4168d366127..e87304a06a85 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -29,6 +29,7 @@ config ARM64 select ARCH_HAS_SYNC_DMA_FOR_CPU select ARCH_HAS_SYSCALL_WRAPPER select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST + select ARCH_HAS_USP_CHECK_SYSCALL select ARCH_HAVE_NMI_SAFE_CMPXCHG select ARCH_INLINE_READ_LOCK if !PREEMPT select ARCH_INLINE_READ_LOCK_BH if !PREEMPT diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 5610ac01c1ec..06566010f6d1 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -11,6 +11,7 @@ #include #include #include +#include #include long compat_arm_syscall(struct pt_regs *regs, int scno); @@ -71,6 +72,9 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, local_daif_restore(DAIF_PROCCTX); user_exit(); + if (!usp_check_syscall()) + force_signal_inject(SIGSEGV, SEGV_MAPERR, GET_USP(regs)); + if (has_syscall_work(flags)) { /* set default errno for user-issued syscall(-1) */ if (scno == NO_SYSCALL) -- 2.11.0