From nobody Tue Apr 7 22:18:02 2026 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 79DE4C433FE for ; Thu, 20 Oct 2022 09:31:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230305AbiJTJbZ (ORCPT ); Thu, 20 Oct 2022 05:31:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230307AbiJTJbQ (ORCPT ); Thu, 20 Oct 2022 05:31:16 -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 5B5C5156244 for ; Thu, 20 Oct 2022 02:31:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666258271; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IBgj4Fw1P4eekn5EviwqvOJ2K/YwxD/QOnBlpto11Zg=; b=O5ryYTQqQFBNfUMm10Pk3t3HoJjEeHge5NrUTwo0znTPDz8j/EAYzNRkTohd1LCxhWowq9 qvMG6V6PJUgq1J3ugEi2luCC1P6f9isK2V6BZRYXv59NMeGtNXGcH23RerVdL3tOOI3dhN GDQSJna7TA9/bw0vI22y8TWlDNFCmxw= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-610-_oUs1GGWOj61jsTPq0Yptw-1; Thu, 20 Oct 2022 05:31:08 -0400 X-MC-Unique: _oUs1GGWOj61jsTPq0Yptw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0EA5885A583; Thu, 20 Oct 2022 09:31:08 +0000 (UTC) Received: from localhost.localdomain (ovpn-192-51.brq.redhat.com [10.40.192.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id 09EC149BB60; Thu, 20 Oct 2022 09:31:04 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Paolo Bonzini , Borislav Petkov , Ingo Molnar , Sean Christopherson , x86@kernel.org, Thomas Gleixner , Dave Hansen , "H. Peter Anvin" , Maxim Levitsky , stable@vger.kernel.org Subject: [PATCH 1/4] KVM: x86: nSVM: leave nested mode on vCPU free Date: Thu, 20 Oct 2022 12:30:52 +0300 Message-Id: <20221020093055.224317-2-mlevitsk@redhat.com> In-Reply-To: <20221020093055.224317-1-mlevitsk@redhat.com> References: <20221020093055.224317-1-mlevitsk@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" If the VM was terminated while nested, we free the nested state while the vCPU still is in nested mode. Soon a warning will be added for this condition. Cc: stable@vger.kernel.org Signed-off-by: Maxim Levitsky --- arch/x86/kvm/svm/svm.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 58f0077d935799..958faa8807f52b 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1439,6 +1439,7 @@ static void svm_vcpu_free(struct kvm_vcpu *vcpu) */ svm_clear_current_vmcb(svm->vmcb); =20 + svm_leave_nested(vcpu); svm_free_nested(svm); =20 sev_free_vcpu(vcpu); --=20 2.26.3 From nobody Tue Apr 7 22:18:02 2026 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 06D57C4167B for ; Thu, 20 Oct 2022 09:31:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230397AbiJTJbj (ORCPT ); Thu, 20 Oct 2022 05:31:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230335AbiJTJbW (ORCPT ); Thu, 20 Oct 2022 05:31:22 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA3E0155DB2 for ; Thu, 20 Oct 2022 02:31:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666258277; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NO7cWLyVclWMKKTiYZzmBycykjfaB0P86+4KIdCX/tM=; b=Mv+5h66M3hORBahuXEiyOg1SJdRNH2XzNc5UICdsEqcO8HDWmp9FsEbUr2ac8vU1tP+prB YOPH26A3aE/pCRKjWRdF0FQTQNwuwpcJsxbqvsjXkOvpPjP9fZrSpW4QT9CltFJxO4BxDm 7IqtjW1ZieUE9cfNqXmszl2TaRRZW7w= 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-201-si_bzrwCPsqHWe6dAUaoPQ-1; Thu, 20 Oct 2022 05:31:11 -0400 X-MC-Unique: si_bzrwCPsqHWe6dAUaoPQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3B30138012DD; Thu, 20 Oct 2022 09:31:11 +0000 (UTC) Received: from localhost.localdomain (ovpn-192-51.brq.redhat.com [10.40.192.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6D32649BB60; Thu, 20 Oct 2022 09:31:08 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Paolo Bonzini , Borislav Petkov , Ingo Molnar , Sean Christopherson , x86@kernel.org, Thomas Gleixner , Dave Hansen , "H. Peter Anvin" , Maxim Levitsky , stable@vger.kernel.org Subject: [PATCH 2/4] KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while still in use Date: Thu, 20 Oct 2022 12:30:53 +0300 Message-Id: <20221020093055.224317-3-mlevitsk@redhat.com> In-Reply-To: <20221020093055.224317-1-mlevitsk@redhat.com> References: <20221020093055.224317-1-mlevitsk@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Make sure that KVM uses vmcb01 before freeing nested state, and warn if that is not the case. This is a minimal fix for CVE-2022-3344 making the kernel print a warning instead of a kernel panic. Cc: stable@vger.kernel.org Signed-off-by: Maxim Levitsky --- arch/x86/kvm/svm/nested.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 4c620999d230a5..b02a3a1792f194 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1125,6 +1125,9 @@ void svm_free_nested(struct vcpu_svm *svm) if (!svm->nested.initialized) return; =20 + if (WARN_ON_ONCE(svm->vmcb !=3D svm->vmcb01.ptr)) + svm_switch_vmcb(svm, &svm->vmcb01); + svm_vcpu_free_msrpm(svm->nested.msrpm); svm->nested.msrpm =3D NULL; =20 --=20 2.26.3 From nobody Tue Apr 7 22:18:02 2026 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 8598CC4332F for ; Thu, 20 Oct 2022 09:31:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230441AbiJTJbm (ORCPT ); Thu, 20 Oct 2022 05:31:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57854 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230372AbiJTJb0 (ORCPT ); Thu, 20 Oct 2022 05:31:26 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B0955147D00 for ; Thu, 20 Oct 2022 02:31:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666258280; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=P73JFXQ3AWZGy0kFIbXH5/4fwtY8KoEObX2sf4YZ6rg=; b=L2f8vb7V/tZcbsO/sunLqpi/4sl0vrE2m74VYIPf/IvpoSHy+P32seDeHxELbD5dyO7MIM foFCoUGl+LhKwf35GnvyrFVp+DkMgHrUf8JzE3+dL86lntsDA8Iq508o5+qB/dk0EL7uvN UXAZ4tXQ/rsgzx/TDDd4F2znShVna8c= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-9-w3fq1VFrN-yCpp6SElqxpQ-1; Thu, 20 Oct 2022 05:31:15 -0400 X-MC-Unique: w3fq1VFrN-yCpp6SElqxpQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6654085A583; Thu, 20 Oct 2022 09:31:14 +0000 (UTC) Received: from localhost.localdomain (ovpn-192-51.brq.redhat.com [10.40.192.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id 99B2249BB60; Thu, 20 Oct 2022 09:31:11 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Paolo Bonzini , Borislav Petkov , Ingo Molnar , Sean Christopherson , x86@kernel.org, Thomas Gleixner , Dave Hansen , "H. Peter Anvin" , Maxim Levitsky , stable@vger.kernel.org Subject: [PATCH 3/4] KVM: x86: add kvm_leave_nested Date: Thu, 20 Oct 2022 12:30:54 +0300 Message-Id: <20221020093055.224317-4-mlevitsk@redhat.com> In-Reply-To: <20221020093055.224317-1-mlevitsk@redhat.com> References: <20221020093055.224317-1-mlevitsk@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Wrap a call to nested_ops->leave_nested into a function. Cc: stable@vger.kernel.org Signed-off-by: Maxim Levitsky --- arch/x86/kvm/svm/nested.c | 3 --- arch/x86/kvm/vmx/nested.c | 3 --- arch/x86/kvm/x86.c | 8 +++++++- 3 files changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index b02a3a1792f194..7354f0035a691d 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1146,9 +1146,6 @@ void svm_free_nested(struct vcpu_svm *svm) svm->nested.initialized =3D false; } =20 -/* - * Forcibly leave nested mode in order to be able to reset the VCPU later = on. - */ void svm_leave_nested(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm =3D to_svm(vcpu); diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 8f67a9c4a28706..a66c5e276ab408 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -6440,9 +6440,6 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu, return kvm_state.size; } =20 -/* - * Forcibly leave nested mode in order to be able to reset the VCPU later = on. - */ void vmx_leave_nested(struct kvm_vcpu *vcpu) { if (is_guest_mode(vcpu)) { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4bd5f8a751de91..d86a8aae1471d3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -628,6 +628,12 @@ static void kvm_queue_exception_vmexit(struct kvm_vcpu= *vcpu, unsigned int vecto ex->payload =3D payload; } =20 +/* Forcibly leave the nested mode in cases like a vCPU reset */ +static void kvm_leave_nested(struct kvm_vcpu *vcpu) +{ + kvm_x86_ops.nested_ops->leave_nested(vcpu); +} + static void kvm_multiple_exception(struct kvm_vcpu *vcpu, unsigned nr, bool has_error, u32 error_code, bool has_payload, unsigned long payload, bool reinject) @@ -5200,7 +5206,7 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct = kvm_vcpu *vcpu, =20 if (events->flags & KVM_VCPUEVENT_VALID_SMM) { if (!!(vcpu->arch.hflags & HF_SMM_MASK) !=3D events->smi.smm) { - kvm_x86_ops.nested_ops->leave_nested(vcpu); + kvm_leave_nested(vcpu); kvm_smm_changed(vcpu, events->smi.smm); } =20 --=20 2.26.3 From nobody Tue Apr 7 22:18:02 2026 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 1CB51C4332F for ; Thu, 20 Oct 2022 09:31:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230478AbiJTJbr (ORCPT ); Thu, 20 Oct 2022 05:31:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230439AbiJTJb3 (ORCPT ); Thu, 20 Oct 2022 05:31:29 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A6CC157F6F for ; Thu, 20 Oct 2022 02:31:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666258283; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nm86sopHALiAvOTB3Mb1uaCRxtNMK3Osw7jYg3LC+M0=; b=PrBzeCYAoQuMxz23urWDMNkIm5te+d7ccZd/Ny3fT2+GBPnEdZQzALrJUB0+ZWxImEOq0R FxlTuhZwN9aiV2wCuoOqdZKlnGjeOvZ3/+qd0nm8GSV8P1te/gh8W9+vapaOfVD/6YmAEk iJ9eu6619IYI28GShB35+XZwssdMIUc= 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-423-MgE-q4rgP1SE4fwskpXN-A-1; Thu, 20 Oct 2022 05:31:18 -0400 X-MC-Unique: MgE-q4rgP1SE4fwskpXN-A-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9305729324B0; Thu, 20 Oct 2022 09:31:17 +0000 (UTC) Received: from localhost.localdomain (ovpn-192-51.brq.redhat.com [10.40.192.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id C4AAC49BB60; Thu, 20 Oct 2022 09:31:14 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Paolo Bonzini , Borislav Petkov , Ingo Molnar , Sean Christopherson , x86@kernel.org, Thomas Gleixner , Dave Hansen , "H. Peter Anvin" , Maxim Levitsky , stable@vger.kernel.org Subject: [PATCH 4/4] KVM: x86: forcibly leave nested mode on vCPU reset Date: Thu, 20 Oct 2022 12:30:55 +0300 Message-Id: <20221020093055.224317-5-mlevitsk@redhat.com> In-Reply-To: <20221020093055.224317-1-mlevitsk@redhat.com> References: <20221020093055.224317-1-mlevitsk@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" While not obivous, kvm_vcpu_reset leaves the nested mode by clearing 'vcpu->arch.hflags' but it does so without all the required housekeeping. This makes SVM and VMX continue to use vmcs02/vmcb02 while the cpu is not in nested mode. In particular, in SVM code, it makes the 'svm_free_nested' free the vmcb02, while still in use, which later triggers use after free and a kernel crash. This issue is assigned CVE-2022-3344 Cc: stable@vger.kernel.org Signed-off-by: Maxim Levitsky --- arch/x86/kvm/x86.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d86a8aae1471d3..313c4a6dc65e45 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11931,6 +11931,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool ini= t_event) WARN_ON_ONCE(!init_event && (old_cr0 || kvm_read_cr3(vcpu) || kvm_read_cr4(vcpu))); =20 + kvm_leave_nested(vcpu); kvm_lapic_reset(vcpu, init_event); =20 vcpu->arch.hflags =3D 0; --=20 2.26.3