From 7b5b29761d9fa40f14da30cf6d60761cb896ec1d Mon Sep 17 00:00:00 2001 From: Josh Boyer Date: Fri, 30 Mar 2012 11:08:12 -0400 Subject: [PATCH] CVE-2012-1601: kvm: NULL dereference from irqchip_in_kernel and vcpu->arch.apic inconsistency (rhbz 808207) --- ...cpus-are-consistent-with-in-kernel-i.patch | 106 ++++++++++++++++++ kernel.spec | 8 ++ 2 files changed, 114 insertions(+) create mode 100644 KVM-Ensure-all-vcpus-are-consistent-with-in-kernel-i.patch diff --git a/KVM-Ensure-all-vcpus-are-consistent-with-in-kernel-i.patch b/KVM-Ensure-all-vcpus-are-consistent-with-in-kernel-i.patch new file mode 100644 index 000000000..7e1664f41 --- /dev/null +++ b/KVM-Ensure-all-vcpus-are-consistent-with-in-kernel-i.patch @@ -0,0 +1,106 @@ +From 5b40572ed5f0344b9dbee486a17c589ce1abe1a3 Mon Sep 17 00:00:00 2001 +From: Avi Kivity +Date: Mon, 5 Mar 2012 14:23:29 +0200 +Subject: [PATCH] KVM: Ensure all vcpus are consistent with in-kernel irqchip + settings + +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 +--- + 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(+), 0 deletions(-) + +diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c +index d8ddbba..f5104b7 100644 +--- a/arch/ia64/kvm/kvm-ia64.c ++++ b/arch/ia64/kvm/kvm-ia64.c +@@ -1172,6 +1172,11 @@ 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 3ee008f..be9594a 100644 +--- a/arch/x86/kvm/x86.c ++++ b/arch/x86/kvm/x86.c +@@ -3199,6 +3199,9 @@ 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) { +@@ -6107,6 +6110,11 @@ 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 355e445..759fa26 100644 +--- a/include/linux/kvm_host.h ++++ b/include/linux/kvm_host.h +@@ -805,6 +805,13 @@ 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 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 e4431ad..94e148e 100644 +--- a/virt/kvm/kvm_main.c ++++ b/virt/kvm/kvm_main.c +@@ -1651,6 +1651,10 @@ 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; +-- +1.7.7.6 + diff --git a/kernel.spec b/kernel.spec index df180f090..cde36fa6e 100644 --- a/kernel.spec +++ b/kernel.spec @@ -793,6 +793,9 @@ Patch21371: iwlwifi-do-not-nulify-ctx-vif-on-reset.patch Patch21500: ASPM-Fix-pcie-devs-with-non-pcie-children.patch Patch21501: nfs-Fix-length-of-buffer-copied-in-__nfs4_get_acl_uncached.patch +#rhbz 808207 CVE-2012-1601 +Patch21520: KVM-Ensure-all-vcpus-are-consistent-with-in-kernel-i.patch + Patch22000: weird-root-dentry-name-debug.patch %endif @@ -1477,6 +1480,9 @@ ApplyPatch ASPM-Fix-pcie-devs-with-non-pcie-children.patch ApplyPatch nfs-Fix-length-of-buffer-copied-in-__nfs4_get_acl_uncached.patch +#rhbz 808207 CVE-2012-1601 +ApplyPatch KVM-Ensure-all-vcpus-are-consistent-with-in-kernel-i.patch + # END OF PATCH APPLICATIONS %endif @@ -2216,6 +2222,8 @@ fi %changelog * Fri Mar 30 2012 Josh Boyer +- CVE-2012-1601: kvm: NULL dereference from irqchip_in_kernel and + vcpu->arch.apic inconsistency (rhbz 808207) - Add patch to fix incorrect buffer length in __nfs4_get_acl_uncached * Thu Mar 29 2012 Josh Boyer - 3.3.0-8