From c1fc1d2f214e33f91565a65ad1b4c09dae618d84 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 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 Signed-off-by: Paolo Bonzini [bwh: Backported to 3.16: use skip_emulated_instruction()] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- 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 3a7ae80dc49d..0a472e9865c5 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -6678,14 +6678,20 @@ 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: -- 2.20.1