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: v4.10.10~37
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b04940e26f100c7d19fc0b5cab0210d4d924b002;p=thirdparty%2Fkernel%2Fstable.git

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>
Cc: "Charles (Chas) Williams" <ciwillia@brocade.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 9764463ce8339..cce7d2e3be15a 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7086,13 +7086,18 @@ 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);
+			return kvm_skip_emulated_instruction(vcpu);
+		}
+		if (*(u32 *)kmap(page) != VMCS12_REVISION) {
 			kunmap(page);
+			nested_release_page_clean(page);
+			nested_vmx_failInvalid(vcpu);
 			return kvm_skip_emulated_instruction(vcpu);
 		}
 		kunmap(page);
+		nested_release_page_clean(page);
 		vmx->nested.vmxon_ptr = vmptr;
 		break;
 	case EXIT_REASON_VMCLEAR: