Am 24.01.2017 um 11:56 schrieb Paolo Bonzini: > 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 <[email protected]> > Signed-off-by: Paolo Bonzini <[email protected]> > --- > arch/x86/kvm/vmx.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 42cc3d6f4d20..0f7345035210 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -7085,13 +7085,18 @@ 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) {
shouldn't we also check if kmap even returned a valid pointer before dereferencing it? David thinks so. > 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: > -- David
