From patchwork Thu Apr 26 13:24:26 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: APPLIED: [PATCH 1/1] [CVE-2012-1601] [ONEIRIC] [NATTY] KVM: Ensure all vcpus are consistent with in-kernel irqchip settings From: Tim Gardner X-Patchwork-Id: 155266 Message-Id: <4F994C8A.8090909@canonical.com> To: Brad Figg Cc: kernel-team@lists.ubuntu.com Date: Thu, 26 Apr 2012 07:24:26 -0600 On 04/26/2012 06:57 AM, Stefan Bader wrote: > On 26.04.2012 14:52, Tim Gardner wrote: >> So this patch causes a compile error. I've attached the correction. I >> suggest that it just be squashed into the original commit. >> >> rtg >> >> >> >> > Maybe we want to pick up the patch that introduced it: > > > commit d780592b99d7d8a5ff905f6bacca519d4a342c76 > Author: Jan Kiszka > Date: Mon May 23 10:33:05 2011 +0200 > > KVM: Clean up error handling during VCPU creation > > Not sure all the jumps to vcpu_destroy before would otherwise do the right thing... > > > > OK, here is the real solution. d780592b99d7d8a5ff905f6bacca519d4a342c76 and 3e515705a1f46beb1c942bb8043c16f8ac7b1e9e are clean cherry-picks. No backport required. rtg >From 08a5694c9cce61f44bc4909ecb947586105374a3 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Mon, 5 Mar 2012 14:23:29 +0200 Subject: [PATCH 2/2] KVM: Ensure all vcpus are consistent with in-kernel irqchip settings BugLink: http://bugs.launchpad.net/bugs/971685 CVE-2012-1601 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 (cherry picked from commit 3e515705a1f46beb1c942bb8043c16f8ac7b1e9e) Signed-off-by: Tim Gardner --- 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 8213efe..a874213 100644 --- a/arch/ia64/kvm/kvm-ia64.c +++ b/arch/ia64/kvm/kvm-ia64.c @@ -1168,6 +1168,11 @@ 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 d829351..bf59dfc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3439,6 +3439,9 @@ long kvm_arch_vm_ioctl(struct file *filp, r = -EEXIST; if (kvm->arch.vpic) goto create_irqchip_unlock; + r = -EINVAL; + if (atomic_read(&kvm->online_vcpus)) + goto create_irqchip_unlock; r = -ENOMEM; vpic = kvm_create_pic(kvm); if (vpic) { @@ -6218,6 +6221,11 @@ 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 31ebb59..d70a250 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -730,6 +730,13 @@ 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 #ifdef __KVM_HAVE_DEVICE_ASSIGNMENT diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 7d6b8e3..f9013d1 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1618,6 +1618,10 @@ 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; -- 1.7.9.5