Messages in this thread | | | Date | Tue, 31 May 2022 11:06:12 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v2 7/8] KVM: x86: Bug the VM if the emulator generates a bogus exception vector |
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On Thu, May 26, 2022 at 09:08:16PM +0000, Sean Christopherson wrote: > Bug the VM if KVM's emulator attempts to inject a bogus exception vector. > The guest is likely doomed even if KVM continues on, and propagating a > bad vector to the rest of KVM runs the risk of breaking other assumptions > in KVM and thus triggering a more egregious bug. > > All existing users of emulate_exception() have hardcoded vector numbers > (__load_segment_descriptor() uses a few different vectors, but they're > all hardcoded), and future users are likely to follow suit, i.e. the > change to emulate_exception() is a glorified nop. > > As for the ctxt->exception.vector check in x86_emulate_insn(), the few > known times the WARN has been triggered in the past is when the field was > not set when synthesizing a fault, i.e. for all intents and purposes the > check protects against consumption of uninitialized data. > > Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-- Kees Cook
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