From patchwork Mon Dec 16 08:47:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 11293583 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 4F6F013B6 for ; Mon, 16 Dec 2019 08:51:21 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 24DC4206D3 for ; Mon, 16 Dec 2019 08:51:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="RlwDjVfD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 24DC4206D3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=3aR5HcGpPVU6d1FupwJcTReR+nDUYtODid9KLEEJ0io=; b=RlwDjVfD+tPcoEQdcGpOk5DFGc fHGi8MnjsIs7B3rWkCfFjOLCzXD+kZghJPuvT0GL/lcLX6vybxJtx+YvdsFoHNDEUP5pT5gGTugVf tDbuxOQytQhhQBCeMqKwzj2FaA/UdSlVHqZxmWH7eW1zgWkxOKDrwTXZ50Yq4Veh6bYg4/vVtOtWP mTmJQYPs6f4kHiQ48P/y4/YauG2LAnt3x3InAXtzOUy+hRwQe7qauO4LY4qFR+3EkZ/+btJCfcPL5 tGsd5MR8YdVAMWBeJ50aInvsBtIaqedubvhdPmf4BSGuk6DzVrfINC8o942YOuKZwqlvTl7vRDZ8D qL3xksaQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1igm61-0008Mx-Ku; Mon, 16 Dec 2019 08:51:17 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1igm35-0004a0-Co for linux-arm-kernel@lists.infradead.org; Mon, 16 Dec 2019 08:48:17 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DC2211007; Mon, 16 Dec 2019 00:48:14 -0800 (PST) Received: from a075553-lin.blr.arm.com (a075553-lin.blr.arm.com [10.162.0.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 28A2F3F6CF; Mon, 16 Dec 2019 00:51:25 -0800 (PST) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 09/16] arm64: mask PAC bits of __builtin_return_address Date: Mon, 16 Dec 2019 14:17:11 +0530 Message-Id: <1576486038-9899-10-git-send-email-amit.kachhap@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1576486038-9899-1-git-send-email-amit.kachhap@arm.com> References: <1576486038-9899-1-git-send-email-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191216_004815_532793_D8A1EE03 X-CRM114-Status: GOOD ( 17.33 ) X-Spam-Score: 0.0 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [217.140.110.172 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Kees Cook , Suzuki K Poulose , Catalin Marinas , Ard Biesheuvel , Richard Henderson , Kristina Martsenko , James Morse , Ramana Radhakrishnan , Amit Daniel Kachhap , Mark Brown , Vincenzo Frascino , Will Deacon , Dave Martin MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org This redefines __builtin_return_address to mask pac bits when Pointer Authentication is enabled. As __builtin_return_address is used mostly used to refer to the caller function symbol address so masking runtime generated pac bits will help to find the match. This patch adds a new file (asm/compiler.h) and is transitively included (via include/compiler_types.h) on the compiler command line so it is guaranteed to be loaded and the users of this macro will not find a wrong version. A helper macro ptrauth_kernel_pac_mask is created for this purpose and added in this file. A similar macro ptrauth_user_pac_mask exists in pointer_auth.h and is now moved here for the sake of consistency. This change fixes the utilities like cat /proc/vmallocinfo to show correct symbol names. Signed-off-by: Amit Daniel Kachhap --- Changes since last version: * Moved pac mask macros from pointer_auth.h to asm/compiler.h as suggested by Ard. * There was suggestion by Richard to use xpaclri/xpac instruction to clear the pack but this needs -march=armv8.3-a GCC option which also generates non-nops instruction like retaa and hence may break the backward compatibility. So it is left like earlier. arch/arm64/Kconfig | 1 + arch/arm64/include/asm/compiler.h | 20 ++++++++++++++++++++ arch/arm64/include/asm/pointer_auth.h | 13 +++++-------- 3 files changed, 26 insertions(+), 8 deletions(-) create mode 100644 arch/arm64/include/asm/compiler.h diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 5aabe8a..06b5025 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -116,6 +116,7 @@ config ARM64 select HAVE_ALIGNED_STRUCT_PAGE if SLUB select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_BITREVERSE + select HAVE_ARCH_COMPILER_H select HAVE_ARCH_HUGE_VMAP select HAVE_ARCH_JUMP_LABEL select HAVE_ARCH_JUMP_LABEL_RELATIVE diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h new file mode 100644 index 0000000..3cb06f9 --- /dev/null +++ b/arch/arm64/include/asm/compiler.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_COMPILER_H +#define __ASM_COMPILER_H + +#if defined(CONFIG_ARM64_PTR_AUTH) + +/* + * The EL0/EL1 pointer bits used by a pointer authentication code. + * This is dependent on TBI0/TBI1 being enabled, or bits 63:56 would also apply. + */ +#define ptrauth_user_pac_mask() GENMASK_ULL(54, vabits_actual) +#define ptrauth_kernel_pac_mask() (GENMASK_ULL(63, 56) | GENMASK_ULL(54, VA_BITS)) + +#define __builtin_return_address(val) \ + (void *)((unsigned long)__builtin_return_address(val) | \ + ptrauth_kernel_pac_mask()) + +#endif /* CONFIG_ARM64_PTR_AUTH */ + +#endif /* __ASM_COMPILER_H */ diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h index 0f89f59..ec33af3 100644 --- a/arch/arm64/include/asm/pointer_auth.h +++ b/arch/arm64/include/asm/pointer_auth.h @@ -68,16 +68,13 @@ static inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel *keys) extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg); -/* - * The EL0 pointer bits used by a pointer authentication code. - * This is dependent on TBI0 being enabled, or bits 63:56 would also apply. - */ -#define ptrauth_user_pac_mask() GENMASK(54, vabits_actual) - -/* Only valid for EL0 TTBR0 instruction pointers */ +/* Valid for EL0 TTBR0 and EL1 TTBR1 instruction pointers */ static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr) { - return ptr & ~ptrauth_user_pac_mask(); + if (ptr & BIT_ULL(55)) + return ptr | ptrauth_kernel_pac_mask(); + else + return ptr & ~ptrauth_user_pac_mask(); } #define ptrauth_thread_init_user(tsk) \