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=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,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 8EFEDC004D2 for ; Tue, 2 Oct 2018 13:30:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59A8B208AE for ; Tue, 2 Oct 2018 13:30:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59A8B208AE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730693AbeJBUOP (ORCPT ); Tue, 2 Oct 2018 16:14:15 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33812 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730643AbeJBUOO (ORCPT ); Tue, 2 Oct 2018 16:14:14 -0400 Received: from localhost (24-104-73-23-ip-static.hfc.comcastbusiness.net [24.104.73.23]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id D91C1C2B; Tue, 2 Oct 2018 13:30:51 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christoffer Dall , Mark Rutland , Dave Martin , Marc Zyngier , Will Deacon Subject: [PATCH 4.18 168/228] arm64: KVM: Tighten guest core register access from userspace Date: Tue, 2 Oct 2018 06:24:25 -0700 Message-Id: <20181002132510.080763631@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20181002132459.032960735@linuxfoundation.org> References: <20181002132459.032960735@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Martin commit d26c25a9d19b5976b319af528886f89cf455692d upstream. We currently allow userspace to access the core register file in about any possible way, including straddling multiple registers and doing unaligned accesses. This is not the expected use of the ABI, and nobody is actually using it that way. Let's tighten it by explicitly checking the size and alignment for each field of the register file. Cc: Fixes: 2f4a07c5f9fe ("arm64: KVM: guest one-reg interface") Reviewed-by: Christoffer Dall Reviewed-by: Mark Rutland Signed-off-by: Dave Martin [maz: rewrote Dave's initial patch to be more easily backported] Signed-off-by: Marc Zyngier Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kvm/guest.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -57,6 +57,45 @@ static u64 core_reg_offset_from_id(u64 i return id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE); } +static int validate_core_offset(const struct kvm_one_reg *reg) +{ + u64 off = core_reg_offset_from_id(reg->id); + int size; + + switch (off) { + case KVM_REG_ARM_CORE_REG(regs.regs[0]) ... + KVM_REG_ARM_CORE_REG(regs.regs[30]): + case KVM_REG_ARM_CORE_REG(regs.sp): + case KVM_REG_ARM_CORE_REG(regs.pc): + case KVM_REG_ARM_CORE_REG(regs.pstate): + case KVM_REG_ARM_CORE_REG(sp_el1): + case KVM_REG_ARM_CORE_REG(elr_el1): + case KVM_REG_ARM_CORE_REG(spsr[0]) ... + KVM_REG_ARM_CORE_REG(spsr[KVM_NR_SPSR - 1]): + size = sizeof(__u64); + break; + + case KVM_REG_ARM_CORE_REG(fp_regs.vregs[0]) ... + KVM_REG_ARM_CORE_REG(fp_regs.vregs[31]): + size = sizeof(__uint128_t); + break; + + case KVM_REG_ARM_CORE_REG(fp_regs.fpsr): + case KVM_REG_ARM_CORE_REG(fp_regs.fpcr): + size = sizeof(__u32); + break; + + default: + return -EINVAL; + } + + if (KVM_REG_SIZE(reg->id) == size && + IS_ALIGNED(off, size / sizeof(__u32))) + return 0; + + return -EINVAL; +} + static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { /* @@ -76,6 +115,9 @@ static int get_core_reg(struct kvm_vcpu (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs) return -ENOENT; + if (validate_core_offset(reg)) + return -EINVAL; + if (copy_to_user(uaddr, ((u32 *)regs) + off, KVM_REG_SIZE(reg->id))) return -EFAULT; @@ -98,6 +140,9 @@ static int set_core_reg(struct kvm_vcpu (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs) return -ENOENT; + if (validate_core_offset(reg)) + return -EINVAL; + if (KVM_REG_SIZE(reg->id) > sizeof(tmp)) return -EINVAL;