4.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ladi Prosek <lpro...@redhat.com>
commit fd19d3b45164466a4adce7cbff448ba9189e1427 upstream.
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 <lpro...@redhat.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/x86/kvm/mmu.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4459,6 +4459,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_
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);
}
