Re: [PATCH v2 2/2] pci: ensure configuration access is within bounds

[P J P]

+-- On Thu, 4 Jun 2020, BALATON Zoltan wrote --+
| On Thu, 4 Jun 2020, P J P wrote:
| > +    assert(address + len <= pci_config_size(d));
| 
| Does this allow guest now to crash QEMU?

Yes, possible. Such crash (assert failure) can be a regular bug, as reading 
PCI configuration is likely a privileged operation inside guest.

| If this is considered to be an error now to call this function with wrong 
| parameters did you check other callers?

No, I haven't checked all other cases.

| Would it be better to not crash just log invalid access and either fix up 
| parameters or return some garbage like 0?

* Earlier patch v1 did the same, returned 0.

* Assert(3) may help to fix current and future incorrect usage of the call.

@mst ...?

Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
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