From: Ladi Prosek Date: Thu, 5 Oct 2017 09:10:22 +0000 (+0200) Subject: KVM: nVMX: update last_nonleaf_level when initializing nested EPT X-Git-Tag: archive/raspbian/4.15.4-1+rpi1~1^2^2^2^2^2~14 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=02b676074bdfd1505cee733efba654d42ec0ca33;p=linux.git KVM: nVMX: update last_nonleaf_level when initializing nested EPT 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 Signed-off-by: Paolo Bonzini Gbp-Pq: Topic bugfix/x86 Gbp-Pq: Name KVM-nVMX-update-last_nonleaf_level-when-initializing.patch --- diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 56e68dfac97..ca011274234 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4459,6 +4459,7 @@ 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); }