Merge git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fix from Marcelo Tosatti: "A correction for user triggerable oops" * git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: x86: invalid opcode oops on SET_SREGS with OSXSAVE bit set (CVE-2012-4461)
quicksilveramalgum · Nov 13, 2012 · 9924a19 · 9924a19
2 parents 946edc4 + 6d1068b
commit 9924a19
Show file tree

Hide file tree

Showing 2 changed files with 6 additions and 0 deletions.
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
@@ -24,6 +24,9 @@ static inline bool guest_cpuid_has_xsave(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpuid_entry2 *best;
 
+	if (!static_cpu_has(X86_FEATURE_XSAVE))
+		return 0;
+
 	best = kvm_find_cpuid_entry(vcpu, 1, 0);
 	return best && (best->ecx & bit(X86_FEATURE_XSAVE));
 }

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
@@ -5781,6 +5781,9 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
 	int pending_vec, max_bits, idx;
 	struct desc_ptr dt;
 
+	if (!guest_cpuid_has_xsave(vcpu) && (sregs->cr4 & X86_CR4_OSXSAVE))
+		return -EINVAL;
+
 	dt.size = sregs->idt.limit;
 	dt.address = sregs->idt.base;
 	kvm_x86_ops->set_idt(vcpu, &dt);