From patchwork Mon Oct 15 16:57:42 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Mattson X-Patchwork-Id: 10642201 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7E89013AD for ; Mon, 15 Oct 2018 16:58:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6E701299B3 for ; Mon, 15 Oct 2018 16:58:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6225A299C2; Mon, 15 Oct 2018 16:58:01 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0CAA3299B3 for ; Mon, 15 Oct 2018 16:58:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726827AbeJPAoC (ORCPT ); Mon, 15 Oct 2018 20:44:02 -0400 Received: from mail-pl1-f201.google.com ([209.85.214.201]:47471 "EHLO mail-pl1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726791AbeJPAoC (ORCPT ); Mon, 15 Oct 2018 20:44:02 -0400 Received: by mail-pl1-f201.google.com with SMTP id t10-v6so553264plh.14 for ; Mon, 15 Oct 2018 09:57:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=gH3vOpfOfjsd5JATN5AuGpFIYfOc4r8pj+3P1JHlAwM=; b=XKZVTxjrjZ70Uma2jzS6ZItzsY7Pf3f08tUMPPFVa71fPDRjO9sYk8LRMQSgUvaFLd vYJCIf8TCWKuywbadnewdkBrzKIGRpH9Oro8YrzrDyfrgjSWe+ZzVb+OvPux7S209KeL kEGM69YBXluk9uhwxM5jpa/92Zin3SsH4rpqPrO0GlKkVA/fzKQ5SveK/3h3cgw8RcYQ IVnlAdAAhNpOyR6a8C0bwzr6AaIuB2Tpy6LIpr0JsSizBhuLowPvEsfhzTsDXhrNY4ew MZ17uweWVNqLdH/WMiTVUTNPzl7l1N4toygfoASt8EMtePDZ9bfs33umCI7Zlb/fBzh4 xSqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=gH3vOpfOfjsd5JATN5AuGpFIYfOc4r8pj+3P1JHlAwM=; b=P68kNOgiCGg5yB+PmJTVXUGvTU/TTzPkirKPTQjrvBAuVmEfGe4smsFbq4Gg5OLLKp yXUSvsz04YS6FnFWataUA7RPUhEyTtdDlbOplLkTbYvmTSzlzOOWRyICRlCN/ARIoxjq VziJYVJQAzeWd0N8CUmyBGFSyOtDGDQls7DGvJV8nHzkdOdaS+/wZ+e6GiokdAN1dasC /DuJdIJ/87i88GvIMWkmdwA6NOPEl/bWHNbtQ5rlAfqBKcFoSzHGnnSzbRssVDGY37V1 oDfv2kWJLjQMVt054HljnuZjCvjgjIkMUcuoaGR8oCqTkPKPZC4t1SumB6PH6TQSgj7K 7geg== X-Gm-Message-State: ABuFfogHYTQ9VYulT5JPRYPTmJSF20ScsLEmCjg1iKwQTV2ffdHQQOaZ 60YgZB6BTI2Ub+En2kTf9Vkn86fBffK6SfIgFVaAOlqphd9gxQn4QQt+/8Qj7lfTExMeyCI+wM4 Q/ahc9OC8FS+wglNCVemvDqsUEFZJMNeHITqg73smsVNEb1y7pMR6pvGcvKFeKqM= X-Google-Smtp-Source: ACcGV61TLB1Rv5I78CdeF1NJNzVIGhHM+SRUu4O0b2pdVvBOmPV4qSdx1tXBjQinztGn/f/Bin+hkkzFq0nPSQ== X-Received: by 2002:a62:c91d:: with SMTP id k29-v6mr8976732pfg.25.1539622678970; Mon, 15 Oct 2018 09:57:58 -0700 (PDT) Date: Mon, 15 Oct 2018 09:57:42 -0700 In-Reply-To: <20181015165742.38393-1-jmattson@google.com> Message-Id: <20181015165742.38393-2-jmattson@google.com> Mime-Version: 1.0 References: <20181015164817.GA25227@linux.intel.com> <20181015165742.38393-1-jmattson@google.com> X-Mailer: git-send-email 2.19.1.331.ge82ca0e54c-goog Subject: [PATCH v3 2/2] kvm: x86: Disallow invalid exceptions from userspace From: Jim Mattson To: kvm@vger.kernel.org Cc: Jim Mattson Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Userspace should not be able to inject an invalid exception into a kvm guest via KVM_SET_VCPU_EVENTS, nor should it be able to convert a valid pending exception to an invalid one via KVM_SET_SREGS. In particular, only certain exceptions deliver an error code in protected mode, and no exception delivers an error code in real-address mode. Reported-by: syzbot Signed-off-by: Jim Mattson Reviewed-by: Marc Orr --- arch/x86/kvm/x86.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4ab569171ad1..b67a664b1d7b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3423,6 +3423,14 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu, vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) return -EINVAL; + if (events->exception.injected) { + bool has_error_code = is_protmode(vcpu) && + x86_exception_has_error_code(events->exception.nr); + + if (!!events->exception.has_error_code != has_error_code) + return -EINVAL; + } + process_nmi(vcpu); vcpu->arch.exception.injected = false; vcpu->arch.exception.pending = events->exception.injected; @@ -8170,6 +8178,14 @@ static int kvm_valid_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) return -EINVAL; } + if (vcpu->arch.exception.injected || vcpu->arch.exception.pending) { + bool has_error_code = (sregs->cr0 & X86_CR0_PE) && + x86_exception_has_error_code(vcpu->arch.exception.nr); + + if (vcpu->arch.exception.has_error_code != has_error_code) + return -EINVAL; + } + return 0; }