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CVE-2012-1601: kvm: NULL dereference from irqchip_in_kernel and 

vcpu->arch.apic inconsistency (rhbz 808207)
This commit is contained in:
Josh Boyer 2012-03-30 11:08:12 -04:00
parent e238325e94
commit c898e790c9
2 changed files with 114 additions and 0 deletions
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106
KVM-Ensure-all-vcpus-are-consistent-with-in-kernel-i.patch Normal file
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@ -0,0 +1,106 @@
From 5b40572ed5f0344b9dbee486a17c589ce1abe1a3 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@redhat.com>
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 <michael@ellerman.id.au>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
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

8
kernel.spec
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@ -787,6 +787,9 @@ Patch21400: unhandled-irqs-switch-to-polling.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
@ -1526,6 +1529,9 @@ 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
@ -2366,6 +2372,8 @@ fi
# '-'
%changelog
* Fri Mar 30 2012 Josh Boyer <jwboyer@redhat.com>
- 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 <jwboyer@redhat.com> - 3.3.0-8