Messages in this thread | | | Subject | Re: [PATCH RESEND] KVM: X86: Fix stack-out-of-bounds read in write_mmio | From | Paolo Bonzini <> | Date | Tue, 12 Dec 2017 17:07:54 +0100 |
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On 12/12/2017 09:57, Wanpeng Li wrote: > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index bc5d853..51e7932 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4690,7 +4690,10 @@ static int write_emulate(struct kvm_vcpu *vcpu, gpa_t gpa, > > static int write_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes, void *val) > { > - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, *(u64 *)val); > + u64 data = 0; > + > + memcpy(&data, val, min(8, bytes)); > + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, data); > return vcpu_mmio_write(vcpu, gpa, bytes, val); > } > >
Please do the memcpy in TRACE_EVENT(kvm_mmio)'s TP_fast_assign block. That is done only when the trace event is active.
Thanks,
Paolo
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