Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH v2 8/8] KVM: x86: Bug the VM on an out-of-bounds data read | Date | Wed, 01 Jun 2022 10:39:10 +0200 |
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Sean Christopherson <seanjc@google.com> writes:
> Bug the VM and terminate emulation if an out-of-bounds read into the > emulator's data cache occurs. Knowingly contuining on all but guarantees > that KVM will overwrite random kernel data, which is far, far worse than > killing the VM. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/emulate.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index 2aa17462a9ac..39ea9138224c 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -1373,7 +1373,8 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt, > if (mc->pos < mc->end) > goto read_cached; > > - WARN_ON((mc->end + size) >= sizeof(mc->data)); > + if (KVM_EMULATOR_BUG_ON((mc->end + size) >= sizeof(mc->data), ctxt)) > + return X86EMUL_UNHANDLEABLE; > > rc = ctxt->ops->read_emulated(ctxt, addr, mc->data + mc->end, size, > &ctxt->exception);
The last WARN_ON() is gone, cool)
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
-- Vitaly
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