From: Ido Yariv Date: Fri, 21 Oct 2016 16:39:57 +0000 (-0400) Subject: KVM: x86: fix wbinvd_dirty_mask use-after-free X-Git-Tag: v3.2.85~62 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=56d95c049be3063654f8d184e069edce371728f4;ds=sidebyside KVM: x86: fix wbinvd_dirty_mask use-after-free 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 Reviewed-by: Paolo Bonzini Signed-off-by: Radim Krčmář [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4ae334a1bd99..fc73c12d488b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6406,11 +6406,13 @@ void kvm_put_guest_fpu(struct kvm_vcpu *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,