From c33d5505d6591863c6d5df082b611f32b8c15ecf Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 24 Jan 2017 11:56:21 +0100 Subject: [PATCH] kvm: fix page struct leak in handle_vmon 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 Signed-off-by: Paolo Bonzini [bwh: Backported to 4.9: use skip_emulated_instruction()] Gbp-Pq: Topic bugfix/x86 Gbp-Pq: Name kvm-fix-page-struct-leak-in-handle_vmon.patch --- arch/x86/kvm/vmx.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 69b8f8a5ecb..43b55ef82ba 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -6925,14 +6925,20 @@ 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: -- 2.30.2