Patch "kvm: fix page struct leak in handle_vmon" has been added to the 4.9-stable tree

Patch "kvm: fix page struct leak in handle_vmon" has been added to the 4.9-stable tree

[gregkh]

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

    kvm: fix page struct leak in handle_vmon

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-fix-page-struct-leak-in-handle_vmon.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 <stable@vger.kernel.org> know about it.


>From 06ce521af9558814b8606c0476c54497cf83a653 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 24 Jan 2017 11:56:21 +0100
Subject: kvm: fix page struct leak in handle_vmon

From: Paolo Bonzini <pbonzini@redhat.com>

commit 06ce521af9558814b8606c0476c54497cf83a653 upstream.

handle_vmon gets a reference on VMXON region page,
but does not release it. Release the reference.

Found by syzkaller; based on a patch by Dmitry.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.16: use skip_emulated_instruction()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/kvm/vmx.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6925,14 +6925,20 @@ static int nested_vmx_check_vmptr(struct
 		}
 
 		page = nested_get_page(vcpu, vmptr);
-		if (page == NULL ||
-		    *(u32 *)kmap(page) != VMCS12_REVISION) {
+		if (page == NULL) {
 			nested_vmx_failInvalid(vcpu);
+			skip_emulated_instruction(vcpu);
+			return 1;
+		}
+		if (*(u32 *)kmap(page) != VMCS12_REVISION) {
 			kunmap(page);
+			nested_release_page_clean(page);
+			nested_vmx_failInvalid(vcpu);
 			skip_emulated_instruction(vcpu);
 			return 1;
 		}
 		kunmap(page);
+		nested_release_page_clean(page);
 		vmx->nested.vmxon_ptr = vmptr;
 		break;
 	case EXIT_REASON_VMCLEAR:


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

queue-4.9/kvm-fix-page-struct-leak-in-handle_vmon.patch