From patchwork Fri Oct 28 17:27:14 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Catalin Marinas X-Patchwork-Id: 80008 Delivered-To: patch@linaro.org Received: by 10.140.97.247 with SMTP id m110csp1291921qge; Fri, 28 Oct 2016 10:31:10 -0700 (PDT) X-Received: by 10.98.21.197 with SMTP id 188mr26666272pfv.38.1477675870701; Fri, 28 Oct 2016 10:31:10 -0700 (PDT) Return-Path: Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id o21si14517246pgj.139.2016.10.28.10.31.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 28 Oct 2016 10:31:10 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) client-ip=2001:1868:205::9; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) smtp.mailfrom=linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1c0Ayp-0005yG-8N; Fri, 28 Oct 2016 17:30:11 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1c0Awo-00043Q-CF for linux-arm-kernel@lists.infradead.org; Fri, 28 Oct 2016 17:28:21 +0000 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 723D8152F; Fri, 28 Oct 2016 10:27:36 -0700 (PDT) Received: from e104818-lin.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 DEC953F220; Fri, 28 Oct 2016 10:27:34 -0700 (PDT) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 6/8] arm64: Handle faults caused by inadvertent user access with PAN enabled Date: Fri, 28 Oct 2016 18:27:14 +0100 Message-Id: <1477675636-3957-7-git-send-email-catalin.marinas@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1477675636-3957-1-git-send-email-catalin.marinas@arm.com> References: <1477675636-3957-1-git-send-email-catalin.marinas@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161028_102806_799006_F521BE5B X-CRM114-Status: GOOD ( 11.80 ) X-Spam-Score: -8.3 (--------) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-8.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [217.140.101.70 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Kees Cook , Ard Biesheuvel , kernel-hardening@lists.openwall.com, Will Deacon , AKASHI Takahiro , James Morse , Sami Tolvanen MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org When TTBR0_EL1 is set to the reserved page, an erroneous kernel access to user space would generate a translation fault. This patch adds the checks for the software-set PSR_PAN_BIT to emulate a permission fault and report it accordingly. Cc: Will Deacon Cc: James Morse Cc: Kees Cook Cc: Mark Rutland Signed-off-by: Catalin Marinas --- arch/arm64/mm/fault.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index d035cc594445..a78a5c401806 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -269,13 +269,19 @@ static int __do_page_fault(struct mm_struct *mm, unsigned long addr, return fault; } -static inline bool is_permission_fault(unsigned int esr) +static inline bool is_permission_fault(unsigned int esr, struct pt_regs *regs) { unsigned int ec = ESR_ELx_EC(esr); unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE; - return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM) || - (ec == ESR_ELx_EC_IABT_CUR && fsc_type == ESR_ELx_FSC_PERM); + if (ec != ESR_ELx_EC_DABT_CUR && ec != ESR_ELx_EC_IABT_CUR) + return false; + + if (system_uses_ttbr0_pan()) + return fsc_type == ESR_ELx_FSC_FAULT && + (regs->pstate & PSR_PAN_BIT); + else + return fsc_type == ESR_ELx_FSC_PERM; } static bool is_el0_instruction_abort(unsigned int esr) @@ -315,7 +321,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, mm_flags |= FAULT_FLAG_WRITE; } - if (is_permission_fault(esr) && (addr < USER_DS)) { + if (addr < USER_DS && is_permission_fault(esr, regs)) { /* regs->orig_addr_limit may be 0 if we entered from EL0 */ if (regs->orig_addr_limit == KERNEL_DS) die("Accessing user space memory with fs=KERNEL_DS", regs, esr);