crypto: ccp: Reject SEV commands with mismatching command buffer

WARN on and reject SEV commands that provide a valid data pointer, but do
not have a known, non-zero length.  And conversely, reject commands that
take a command buffer but none is provided (data is null).

Aside from sanity checking input, disallowing a non-null pointer without
a non-zero size will allow a future patch to cleanly handle vmalloc'd
data by copying the data to an internal __pa() friendly buffer.

Note, this also effectively prevents callers from using commands that
have a non-zero length and are not known to the kernel.  This is not an
explicit goal, but arguably the side effect is a good thing from the
kernel's perspective.

Cc: Brijesh Singh <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Tom Lendacky <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Brijesh Singh <[email protected]>
Acked-by: Tom Lendacky <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

0 files changed, 0 insertions, 0 deletions