From patchwork Thu Apr 26 16:37:39 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brad Figg X-Patchwork-Id: 155298 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from chlorine.canonical.com (chlorine.canonical.com [91.189.94.204]) by ozlabs.org (Postfix) with ESMTP id 89BF6B6FBD for ; Fri, 27 Apr 2012 02:38:02 +1000 (EST) Received: from localhost ([127.0.0.1] helo=chlorine.canonical.com) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1SNRhV-0003Xi-36; Thu, 26 Apr 2012 16:37:49 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1SNRhS-0003WS-PT for kernel-team@lists.ubuntu.com; Thu, 26 Apr 2012 16:37:46 +0000 Received: from static-50-53-107-235.bvtn.or.frontiernet.net ([50.53.107.235] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1SNRhS-0003ZJ-DR for kernel-team@lists.ubuntu.com; Thu, 26 Apr 2012 16:37:46 +0000 From: Brad Figg To: kernel-team@lists.ubuntu.com Subject: [PATCH 1/1] [CVE-2012-1601] [LUCID] KVM: Ensure all vcpus are consistent with in-kernel irqchip settings Date: Thu, 26 Apr 2012 09:37:39 -0700 Message-Id: <1335458259-8920-3-git-send-email-brad.figg@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1335458259-8920-1-git-send-email-brad.figg@canonical.com> References: <1335458259-8920-1-git-send-email-brad.figg@canonical.com> X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.13 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: kernel-team-bounces@lists.ubuntu.com Errors-To: kernel-team-bounces@lists.ubuntu.com From: Avi Kivity CVE-2012-1601 BugLink: http://bugs.launchpad.net/bugs/971685 If some vcpus are created before KVM_CREATE_IRQCHIP, then irqchip_in_kernel() and vcpu->arch.apic will be inconsistent, leading to potential NULL pointer dereferences. Fix by: - ensuring that no vcpus are installed when KVM_CREATE_IRQCHIP is called - ensuring that a vcpu has an apic if it is installed after KVM_CREATE_IRQCHIP This is somewhat long winded because vcpu->arch.apic is created without kvm->lock held. Based on earlier patch by Michael Ellerman. Signed-off-by: Michael Ellerman Signed-off-by: Avi Kivity (backported from commit 3e515705a1f46beb1c942bb8043c16f8ac7b1e9e upstream) Signed-off-by: Brad Figg --- arch/ia64/kvm/kvm-ia64.c | 5 +++++ arch/x86/kvm/x86.c | 8 ++++++++ include/linux/kvm_host.h | 7 +++++++ virt/kvm/kvm_main.c | 4 ++++ 4 files changed, 24 insertions(+) diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c index 2eb6365..416122b 100644 --- a/arch/ia64/kvm/kvm-ia64.c +++ b/arch/ia64/kvm/kvm-ia64.c @@ -1185,6 +1185,11 @@ out: #define PALE_RESET_ENTRY 0x80000000ffffffb0UL +bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu) +{ + return irqchip_in_kernel(vcpu->kcm) == (vcpu->arch.apic != NULL); +} + int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) { struct kvm_vcpu *v; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7000a5e..34813ce 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2274,6 +2274,9 @@ long kvm_arch_vm_ioctl(struct file *filp, goto out; break; case KVM_CREATE_IRQCHIP: + r = -EINVAL; + if (atomic_read(&kvm->online_vcpus)) + goto out; r = -ENOMEM; kvm->arch.vpic = kvm_create_pic(kvm); if (kvm->arch.vpic) { @@ -5007,6 +5010,11 @@ void kvm_arch_check_processor_compat(void *rtn) kvm_x86_ops->check_processor_compatibility(rtn); } +bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu) +{ + return irqchip_in_kernel(vcpu->kvm) == (vcpu->arch.apic != NULL); +} + int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) { struct page *page; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 1296deb..624cf6b 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -557,5 +557,12 @@ static inline bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu) { return vcpu->kvm->bsp_vcpu_id == vcpu->vcpu_id; } + +bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu); + +#else + +static inline bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu) { return true; } + #endif #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 42d7353..a27f14f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1872,6 +1872,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) goto vcpu_destroy; mutex_lock(&kvm->lock); + if (!kvm_vcpu_compatible(vcpu)) { + r = -EINVAL; + goto unlock_vcpu_destroy; + } if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) { r = -EINVAL; goto unlock_vcpu_destroy;