From patchwork Mon Apr 19 13:06:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 424483 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, 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 BC443C433B4 for ; Mon, 19 Apr 2021 13:15:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9DD14613E6 for ; Mon, 19 Apr 2021 13:15:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239880AbhDSNPd (ORCPT ); Mon, 19 Apr 2021 09:15:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:45438 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240005AbhDSNN6 (ORCPT ); Mon, 19 Apr 2021 09:13:58 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A7F7D613C5; Mon, 19 Apr 2021 13:12:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618837948; bh=56budua+6takyPNt7djZvnt25kiRnmy34gmsgwEXX/E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wQW/bkwggCXFVi4iLopFDA9UbCaEpWZLUgU+OIni8hkLaQSe9wV4mX5Id0zdPDoMs rhYtjrLL0AU9+ZqP+ekuoelqOc1/kTsHHJwd0m6ABQy4wAItXicC3Wpgg7TwMf5kbL HRl07HVJalUzIEEfQBzrLHbW6wmF78i+hB0Ekj9s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Reiji Watanabe , Jim Mattson , Paolo Bonzini , Sasha Levin Subject: [PATCH 5.11 112/122] KVM: VMX: Dont use vcpu->run->internal.ndata as an array index Date: Mon, 19 Apr 2021 15:06:32 +0200 Message-Id: <20210419130533.974872558@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210419130530.166331793@linuxfoundation.org> References: <20210419130530.166331793@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Reiji Watanabe [ Upstream commit 04c4f2ee3f68c9a4bf1653d15f1a9a435ae33f7a ] __vmx_handle_exit() uses vcpu->run->internal.ndata as an index for an array access. Since vcpu->run is (can be) mapped to a user address space with a writer permission, the 'ndata' could be updated by the user process at anytime (the user process can set it to outside the bounds of the array). So, it is not safe that __vmx_handle_exit() uses the 'ndata' that way. Fixes: 1aa561b1a4c0 ("kvm: x86: Add "last CPU" to some KVM_EXIT information") Signed-off-by: Reiji Watanabe Reviewed-by: Jim Mattson Message-Id: <20210413154739.490299-1-reijiw@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kvm/vmx/vmx.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 880a2617820c..95f836fbceb2 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -5986,19 +5986,19 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) exit_reason.basic != EXIT_REASON_PML_FULL && exit_reason.basic != EXIT_REASON_APIC_ACCESS && exit_reason.basic != EXIT_REASON_TASK_SWITCH)) { + int ndata = 3; + vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_DELIVERY_EV; - vcpu->run->internal.ndata = 3; vcpu->run->internal.data[0] = vectoring_info; vcpu->run->internal.data[1] = exit_reason.full; vcpu->run->internal.data[2] = vcpu->arch.exit_qualification; if (exit_reason.basic == EXIT_REASON_EPT_MISCONFIG) { - vcpu->run->internal.ndata++; - vcpu->run->internal.data[3] = + vcpu->run->internal.data[ndata++] = vmcs_read64(GUEST_PHYSICAL_ADDRESS); } - vcpu->run->internal.data[vcpu->run->internal.ndata++] = - vcpu->arch.last_vmentry_cpu; + vcpu->run->internal.data[ndata++] = vcpu->arch.last_vmentry_cpu; + vcpu->run->internal.ndata = ndata; return 0; }