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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81B1FC4332F for ; Thu, 3 Nov 2022 13:58:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231528AbiKCN6q (ORCPT ); Thu, 3 Nov 2022 09:58:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229994AbiKCN6m (ORCPT ); Thu, 3 Nov 2022 09:58:42 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BF4F14D3A for ; Thu, 3 Nov 2022 06:57:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667483865; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=fUsqybhXp/D82YuS/O33LZfOTzfFB038d5lKiyOEhC8=; b=OODV3/lAkc4pzzBsU8BEhraCLDz3bBGlVKpW1NF2WLUOEorsMlhV9Tj5pljfJ7n2htwLIZ p/1SXtQH8cE0eDwXrDZ4LOY/HE0pa1c2IXCdC2NzLdJY0fVB9R7X2JHjETTGGV1rd1XkkP Ar7j6KSzQ/jAgx15StyGmoPRNjIfPpA= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-528-wG8_w1AzN_-3brZ9aiF0Rw-1; Thu, 03 Nov 2022 09:57:41 -0400 X-MC-Unique: wG8_w1AzN_-3brZ9aiF0Rw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BD30A3815D2F; Thu, 3 Nov 2022 13:57:40 +0000 (UTC) Received: from amdlaptop.tlv.redhat.com (dhcp-4-238.tlv.redhat.com [10.35.4.238]) by smtp.corp.redhat.com (Postfix) with ESMTP id 52F8B40C2140; Thu, 3 Nov 2022 13:57:37 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: Paolo Bonzini , "H. Peter Anvin" , Shuah Khan , Yang Zhong , Wei Wang , Colton Lewis , Sean Christopherson , Jim Mattson , Chenyi Qiang , Borislav Petkov , linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Dave Hansen , Ingo Molnar , David Matlack , Peter Xu , Maxim Levitsky , linux-kselftest@vger.kernel.org Subject: [PATCH 0/9] nSVM: Security and correctness fixes Date: Thu, 3 Nov 2022 15:57:27 +0200 Message-Id: <20221103135736.42295-1-mlevitsk@redhat.com> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Recently while trying to fix some unit tests I found a CVE in SVM nested co= de.=0D =0D In 'shutdown_interception' vmexit handler we call kvm_vcpu_reset.=0D =0D However if running nested and L1 doesn't intercept shutdown, we will still = end=0D up running this function and trigger a bug in it.=0D =0D The bug is that this function resets the 'vcpu->arch.hflags' without proper= ly=0D leaving the nested state, which leaves the vCPU in inconsistent state, whic= h=0D later triggers a kernel panic in SVM code.=0D =0D The same bug can likely be triggered by sending INIT via local apic to a vC= PU=0D which runs a nested guest.=0D =0D On VMX we are lucky that the issue can't happen because VMX always intercep= ts=0D triple faults, thus triple fault in L2 will always be redirected to L1.=0D Plus the 'handle_triple_fault' of VMX doesn't reset the vCPU.=0D =0D INIT IPI can't happen on VMX either because INIT events are masked while in= =0D VMX mode.=0D =0D First 4 patches in this series address the above issue, and are=0D already posted on the list with title,=0D ('nSVM: fix L0 crash if L2 has shutdown condtion which L1 doesn't intercept= ')=0D I addressed the review feedback and also added a unit test to hit this issu= e.=0D =0D In addition to these patches I noticed that KVM doesn't honour SHUTDOWN int= ercept bit=0D of L1 on SVM, and I included a fix to do so - its only for correctness=0D as a normal hypervisor should always intercept SHUTDOWN.=0D A unit test on the other hand might want to not do so.=0D I also extendted the triple_fault_test selftest to hit this issue.=0D =0D Finaly I found another security issue, I found a way to=0D trigger a kernel non rate limited printk on SVM from the guest, and=0D last patch in the series fixes that.=0D =0D A unit test I posted to kvm-unit-tests project hits this issue, so=0D no selftest was added.=0D =0D Best regards,=0D Maxim Levitsky=0D =0D Maxim Levitsky (9):=0D KVM: x86: nSVM: leave nested mode on vCPU free=0D KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while=0D still in use=0D KVM: x86: add kvm_leave_nested=0D KVM: x86: forcibly leave nested mode on vCPU reset=0D KVM: selftests: move idt_entry to header=0D kvm: selftests: add svm nested shutdown test=0D KVM: x86: allow L1 to not intercept triple fault=0D KVM: selftests: add svm part to triple_fault_test=0D KVM: x86: remove exit_int_info warning in svm_handle_exit=0D =0D arch/x86/kvm/svm/nested.c | 12 +++-=0D arch/x86/kvm/svm/svm.c | 10 +--=0D arch/x86/kvm/vmx/nested.c | 4 +-=0D arch/x86/kvm/x86.c | 29 ++++++--=0D tools/testing/selftests/kvm/.gitignore | 1 +=0D tools/testing/selftests/kvm/Makefile | 1 +=0D .../selftests/kvm/include/x86_64/processor.h | 13 ++++=0D .../selftests/kvm/lib/x86_64/processor.c | 13 ----=0D .../kvm/x86_64/svm_nested_shutdown_test.c | 71 +++++++++++++++++++=0D .../kvm/x86_64/triple_fault_event_test.c | 71 ++++++++++++++-----=0D 10 files changed, 174 insertions(+), 51 deletions(-)=0D create mode 100644 tools/testing/selftests/kvm/x86_64/svm_nested_shutdown_= test.c=0D =0D -- =0D 2.34.3=0D =0D