Patch "KVM: nVMX: update last_nonleaf_level when initializing nested EPT" has been added to the 4.9-stable tree

From fd19d3b45164466a4adce7cbff448ba9189e1427 Mon Sep 17 00:00:00 2001

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 4.9-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-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From fd19d3b45164466a4adce7cbff448ba9189e1427 Mon Sep 17 00:00:00 2001
From: Ladi Prosek <[email protected]>
Date: Thu, 5 Oct 2017 11:10:22 +0200
Subject: KVM: nVMX: update last_nonleaf_level when initializing nested EPT

From: Ladi Prosek <[email protected]>

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 <[email protected]>

Signed-off-by Paolo Bonzini <[email protected]>

Signed-off-by Greg Kroah-Hartman <[email protected]>

---
 arch/x86/kvm/mmu.c |    1 +
 1 file changed, 1 insertion(+)

arch/x86/kvm/mmu.c +1 -0

@@ -4169,6 +4169,7 @@ 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 [email protected] are

queue-4.9/kvm-nvmx-update-last_nonleaf_level-when-initializing-nested-ept.patch queue-4.9/kvm-mmu-always-terminate-page-walks-at-level-1.patch