From: Ladi Prosek <[email protected]> The function updates context->root_level but didn't call update_last_nonleaf_level so the previous and potentially wrong value was used for page walks. For example, a zero value of last_nonleaf_level would allow a potential out-of-bounds access in arch/x86/mmu/paging_tmpl.h's walk_addr_generic function (CVE-2017-12188).
Fixes: 155a97a3d7c78b46cef6f1a973c831bc5a4f82bb Signed-off-by: Ladi Prosek <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]> --- arch/x86/kvm/mmu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 106d4a029a8a..3c25f20115bc 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4555,6 +4555,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly, update_permission_bitmask(vcpu, context, true); update_pkru_bitmask(vcpu, context, true); + update_last_nonleaf_level(vcpu, context); reset_rsvds_bits_mask_ept(vcpu, context, execonly); reset_ept_shadow_zero_bits_mask(vcpu, context, execonly); } -- 1.8.3.1
