SecurityPkg/RngDxe: Conditionally install EFI_RNG_PROTOCOL

On Arm platforms, the number of available RNG algorithms is
dynamically detected and can be 0 in the absence of FEAT_RNG
and firmware TRNG.
In this case, the EFI_RNG_PROTOCOL should not be installed to
prevent from installing an empty protocol.

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
[ardb: return EFI_REQUEST_UNLOAD_IMAGE instead of an error]
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Pierre Gondois 2022-11-24 17:17:55 +01:00 committed by mergify[bot]
parent bfb574db11
commit 75fb0cfc82
1 changed files with 14 additions and 5 deletions

View File

@ -63,6 +63,18 @@ RngDriverEntry (
EFI_STATUS Status;
EFI_HANDLE Handle;
//
// Get the list of available algorithm.
//
Status = GetAvailableAlgorithms ();
if (EFI_ERROR (Status)) {
return Status;
}
if (mAvailableAlgoArrayCount == 0) {
return EFI_REQUEST_UNLOAD_IMAGE;
}
//
// Install UEFI RNG (Random Number Generator) Protocol
//
@ -74,13 +86,10 @@ RngDriverEntry (
NULL
);
if (EFI_ERROR (Status)) {
return Status;
FreeAvailableAlgorithms ();
}
//
// Get the list of available algorithm.
//
return GetAvailableAlgorithms ();
return Status;
}
/**