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From patchwork Tue Jan 24 10:56:21 2017
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Content-Type: text/plain; charset="utf-8"
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MIME-Version: 1.0
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Content-Transfer-Encoding: 7bit
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Subject: kvm: fix page struct leak in handle_vmon
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From: Paolo Bonzini <pbonzini@redhat.com>
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X-Patchwork-Id: 9534885
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Message-Id: <1485255381-18069-1-git-send-email-pbonzini@redhat.com>
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To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
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Cc: dvyukov@google.com
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Date: Tue, 24 Jan 2017 11:56:21 +0100
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handle_vmon gets a reference on VMXON region page,
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but does not release it. Release the reference.
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Found by syzkaller; based on a patch by Dmitry.
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Reported-by: Dmitry Vyukov <dvyukov@google.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Reviewed-by: David Hildenbrand <david@redhat.com>
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---
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arch/x86/kvm/vmx.c | 9 +++++++--
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1 file changed, 7 insertions(+), 2 deletions(-)
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diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
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index 42cc3d6f4d20..0f7345035210 100644
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--- a/arch/x86/kvm/vmx.c
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+++ b/arch/x86/kvm/vmx.c
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@@ -7085,13 +7085,18 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu *vcpu, int exit_reason,
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}
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page = nested_get_page(vcpu, vmptr);
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- if (page == NULL ||
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- *(u32 *)kmap(page) != VMCS12_REVISION) {
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+ if (page == NULL) {
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nested_vmx_failInvalid(vcpu);
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+ return kvm_skip_emulated_instruction(vcpu);
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+ }
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+ if (*(u32 *)kmap(page) != VMCS12_REVISION) {
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kunmap(page);
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+ nested_release_page_clean(page);
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+ nested_vmx_failInvalid(vcpu);
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return kvm_skip_emulated_instruction(vcpu);
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}
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kunmap(page);
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+ nested_release_page_clean(page);
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vmx->nested.vmxon_ptr = vmptr;
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break;
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case EXIT_REASON_VMCLEAR:
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