| From | Ben Hutchings <> | Date | Wed, 15 Feb 2017 22:41:40 +0000 | Subject | [PATCH 3.16 178/306] KVM: x86: fix wbinvd_dirty_mask use-after-free |
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3.16.40-rc1 review patch. If anyone has any objections, please let me know.
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From: Ido Yariv <ido@wizery.com>
commit bd768e146624cbec7122ed15dead8daa137d909d upstream.
vcpu->arch.wbinvd_dirty_mask may still be used after freeing it, corrupting memory. For example, the following call trace may set a bit in an already freed cpu mask: kvm_arch_vcpu_load vcpu_load vmx_free_vcpu_nested vmx_free_vcpu kvm_arch_vcpu_free
Fix this by deferring freeing of wbinvd_dirty_mask.
Signed-off-by: Ido Yariv <ido@wizery.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- arch/x86/kvm/x86.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6809,11 +6809,13 @@ void kvm_put_guest_fpu(struct kvm_vcpu * void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu) { + void *wbinvd_dirty_mask = vcpu->arch.wbinvd_dirty_mask; + kvmclock_reset(vcpu); - free_cpumask_var(vcpu->arch.wbinvd_dirty_mask); fx_free(vcpu); kvm_x86_ops->vcpu_free(vcpu); + free_cpumask_var(wbinvd_dirty_mask); } struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
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