From patchwork Mon Oct 15 16:41:24 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Mattson X-Patchwork-Id: 10642181 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 7B4F9925 for ; Mon, 15 Oct 2018 16:41:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 69C1729A74 for ; Mon, 15 Oct 2018 16:41:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5DC4629A7E; Mon, 15 Oct 2018 16:41:36 +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 D873B29A74 for ; Mon, 15 Oct 2018 16:41:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726714AbeJPA1e (ORCPT ); Mon, 15 Oct 2018 20:27:34 -0400 Received: from mail-yb1-f201.google.com ([209.85.219.201]:36876 "EHLO mail-yb1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726663AbeJPA1d (ORCPT ); Mon, 15 Oct 2018 20:27:33 -0400 Received: by mail-yb1-f201.google.com with SMTP id z1-v6so11110506ybf.4 for ; Mon, 15 Oct 2018 09:41:34 -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=fn1DfEU08YGQH3Y+5IXM9BWNZYL9RAr6yFtWICxf5GTNH4NfgRz0t8yzLBa7S1dA2S VBpu+iEwzRdh77Hmtk12JhIFD1Arm82LLdO5ejS8e00IFsf9zWrZHdGo7fm9CIxxfPil fkjKytg9NI7Tx6s74XD0/OhSL4dsW0//0Mb3X+f60mMQ0yWT36wh5jWp77BolyZ1sgVc q600eaa0eSQHRy0mSY48XlQgLlclzSLFbps1bsn/g3UBHV5wBafuG4UV7Q2qJNn8oD5G eFvtsaQmpGYYimolHlTUfez6t7IDZ9XXqorK2/PeFQHS+TAy/qfx88EwymBNC5hdxhSG aBDw== 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=RDEtzZaEC3zmagO89G4PAlATzR02GXCtmG2DigKH8R0iUYnal6XUEqusLgM3Kzchow wU03N2ijYO/JgpP/Rx7Jkr1CrkNd5uyf8t/6bOXLXEtXPpHW5v9sgc0kREtaXQniZQ4m +cnm2xU3OHI4FhJZgZacZDhpdL723iyozM7MSNY9+R65TBCcRRWqgzg6p5pOtp8TsNnV gwQe7ZxcpE5caXeyG1exDkBJt0i6JUpQt1lGwQ7o6/ubogB7i/tAM6+/7jrMtW3aOoaw g2Ut99/nCvxym1rel8APDFjTWKUhyKm5skMPwtesrGL3fwf7NxSAPrkEbwSqfURaH3dr Uzyw== X-Gm-Message-State: ABuFfogJMan/ypoTynHrpMY5+OETL+/cgFAUerVMTvHNjVA9OyQedDKc CX+tz6XvFVz14sxIqPqydbCRHdYtvUb+9Qa122EYt9Wx5QO49SrzUkGGIlujHO802F71hxxO8R1 7hdSeL8M58SKaagj+0OmYEWLmGSGjpb+rp1WkXEKEHWhhvyBYWw/fXILoC8UB3fQ= X-Google-Smtp-Source: ACcGV61KXOw1VzUKaTzynPqYza2XaRLb9yw1faTx9umhWJmcGG5P+2+a9XiAUMXPFcp/oSnIL3C6tHwDNDCuhA== X-Received: by 2002:a25:38d1:: with SMTP id f200-v6mr9898924yba.59.1539621693748; Mon, 15 Oct 2018 09:41:33 -0700 (PDT) Date: Mon, 15 Oct 2018 09:41:24 -0700 In-Reply-To: <20181015164124.225764-1-jmattson@google.com> Message-Id: <20181015164124.225764-2-jmattson@google.com> Mime-Version: 1.0 References: <20181015164124.225764-1-jmattson@google.com> X-Mailer: git-send-email 2.19.1.331.ge82ca0e54c-goog Subject: [PATCH v2 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; }