47894e0fa6
The AMD Secure Processor (ASP) and an SNP guest use a series of
AES-GCM keys called VMPCKs to communicate securely with each other.
The IV to this scheme is a sequence number that both the ASP and the
guest track.
Currently, this sequence number in a guest request must exactly match
the sequence number tracked by the ASP. This means that if the guest
sees an error from the host during a request it can only retry that
exact request or disable the VMPCK to prevent an IV reuse. AES-GCM
cannot tolerate IV reuse, see: "Authentication Failures in NIST version
of GCM" - Antoine Joux et al.
In order to address this, make handle_guest_request() delete the VMPCK
on any non successful return. To allow userspace querying the cert_data
length make handle_guest_request() save the number of pages required by
the host, then have handle_guest_request() retry the request without
requesting the extended data, then return the number of pages required
back to userspace.
[ bp: Massage, incorporate Tom's review comments. ]
Fixes:
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|---|---|---|
| .. | ||
| acrn | ||
| coco | ||
| nitro_enclaves | ||
| vboxguest | ||
| Kconfig | ||
| Makefile | ||
| fsl_hypervisor.c | ||
| vmgenid.c | ||