From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 24 Jan 2017 10:56:21 +0000 (+0100)
Subject: kvm: fix page struct leak in handle_vmon
X-Git-Tag: v3.16.42~6
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=591fc80b6369a886a1d21cacf11f91b455781df3;p=linux

kvm: fix page struct leak in handle_vmon

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>
---

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7b16666d6ed4..dad945386800 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5954,14 +5954,20 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu *vcpu, int exit_reason,
 		}
 
 		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: