Messages in this thread | | | Date | Thu, 11 Nov 2021 17:01:09 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v6 19/42] x86/mm: Add support to validate memory when changing C-bit |
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On Thu, Nov 11, 2021 at 08:49:49AM -0600, Tom Lendacky wrote: > 2032 => sizeof(ghcb->shared_buffer) ?
Or that.
> The idea is that a full snp_psc_desc structure is meant to fit completely in > the shared_buffer area. So if there are no compile time checks, then the > code on the HV side will need to ensure that the input doesn't cause the HV > to access the structure outside of the shared_buffer area - which, IIRC, it > does (think protect against a malicious guest), so the min_t() on the memcpy > should be safe on the guest side. > > But given the snp_psc_desc is sized/meant to fit completely in the > shared_buffer, a compile time check would be a good idea, too, right?
If the desc thing is meant to fit, then a compile-time check is also a good way to express that intention. So yeah.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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