From patchwork Thu Jan 23 10:20:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 11347269 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 BC3AA13A4 for ; Thu, 23 Jan 2020 10:24:28 +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 97A7124125 for ; Thu, 23 Jan 2020 10:24:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="V08iFh64" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 97A7124125 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=VpdHqF3t09vptw9kxkaVDjvGAIJ+xmNVZb5wRdiFj0Q=; b=V08iFh64hRSBUE/6Akz9PBsHmu IRybdHPv4GCU7y0jdw+cOwoW3Rfl4/09p8L0AO8TD4y0BelZlLv9d46pi0QmjlM0RuaLlCM8o3F+N g4OX8Tr58IHQLzPktYxnOFaFrtzm8lbgwEGadGKT8K8jAY5RXkwEjj//SalAeEatz+x1S8SuSXCM/ y6RnuSv1jogWk39cmqxz5yNGQKUmY8LsYP0aqm3rdE653UnskQnIc2wcJq2qdNGTS8nyj+aTmY/Vc UMHiT6REYah0Su6pFllFrhnZwB+LZglql13wYtkRXwV5WwiM66/MeOKmGb7tuW6D6eOUmqrtnLjij NY1BpIeA==; 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 1iuZez-0000Gm-Ok; Thu, 23 Jan 2020 10:24:25 +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 1iuZcQ-0006Ny-G6 for linux-arm-kernel@lists.infradead.org; Thu, 23 Jan 2020 10:21:48 +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 EA84131B; Thu, 23 Jan 2020 02:21:45 -0800 (PST) Received: from a075553-lin.blr.arm.com (a075553-lin.blr.arm.com [10.162.17.79]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 438A63F6C4; Thu, 23 Jan 2020 02:21:42 -0800 (PST) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 11/17] arm64: mask PAC bits of __builtin_return_address Date: Thu, 23 Jan 2020 15:50:33 +0530 Message-Id: <1579774839-19562-12-git-send-email-amit.kachhap@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1579774839-19562-1-git-send-email-amit.kachhap@arm.com> References: <1579774839-19562-1-git-send-email-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200123_022146_648681_BB34B166 X-CRM114-Status: GOOD ( 16.15 ) X-Spam-Score: -0.7 (/) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-0.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low 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 , Kristina Martsenko , Dave Martin , Mark Brown , James Morse , Ramana Radhakrishnan , Amit Daniel Kachhap , Vincenzo Frascino , Will Deacon , Ard Biesheuvel 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 v3: * Changed VA_BITS to vabits_actual for kernel pacmask as pointed by Catalin [1]. [1]: http://lists.infradead.org/pipermail/linux-arm-kernel/2020-January/706604.html 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 86cb782..beded60 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..085e7cd0 --- /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, vabits_actual) + +#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 833d3f9..5340dbb 100644 --- a/arch/arm64/include/asm/pointer_auth.h +++ b/arch/arm64/include/asm/pointer_auth.h @@ -68,16 +68,13 @@ static __always_inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kerne 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) \