Patch "KVM: nVMX: update last_nonleaf_level when initializing nested EPT" has been added to the 4.13-stable tree

Patch "KVM: nVMX: update last_nonleaf_level when initializing nested EPT" has been added to the 4.13-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    KVM: nVMX: update last_nonleaf_level when initializing nested EPT

to the 4.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kvm-nvmx-update-last_nonleaf_level-when-initializing-nested-ept.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From fd19d3b45164466a4adce7cbff448ba9189e1427 Mon Sep 17 00:00:00 2001
From: Ladi Prosek <lprosek@redhat.com>
Date: Thu, 5 Oct 2017 11:10:22 +0200
Subject: KVM: nVMX: update last_nonleaf_level when initializing nested EPT

From: Ladi Prosek <lprosek@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 <lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@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);
 }


Patches currently in stable-queue which might be from lprosek@redhat.com are

queue-4.13/kvm-nvmx-update-last_nonleaf_level-when-initializing-nested-ept.patch
queue-4.13/kvm-mmu-always-terminate-page-walks-at-level-1.patch