fuchsia.hardware.block.encrypted

PROTOCOLS

DeviceManager

Defined in fuchsia.hardware.block.encrypted/devicemanager.fidl

An interface to the zxcrypt driver, as bound to a single block device with a zxcrypt superblock. zxcrypt devices are encrypted, and before their plaintext contents can be accessed, they must be unsealed with a key. This protocol allows the caller to make requests to unseal the device (by providing the appropriate key) and to seal the device (rendering its contents inaccessible).

Unseal

Attempts to unseal the device by using the provided master key to unwrap the data key wrapped in the specified key slot. If the key provided was the correct key for this slot, then the device node responding to this protocol will create an unsealed zxcrypt device as a child of itself in the device tree before returning success. Returns ZX_ERR_INVALID_ARGS if slot is invalid. Returns ZX_ERR_BAD_STATE and keeps the device open if the device is already unsealed. Returns other errors if operations on the underlying block device return errors. Returns ZX_OK on success.

Request

NameType
key vector<uint8>[256]
slot uint8

Response

NameType
status zx/status

Seal

Seals the device, causing any previously-created child zxcrypt Device to be removed some time later. (Someday we'd like this to only return once the unsealed child device is removed, but that's not straightforward today.) Returns ZX_ERR_BAD_STATE if the device is already sealed. Returns ZX_OK on success.

Request

NameType

Response

NameType
status zx/status

Shred

Shreds the device, permanently overwriting the keys that would allow Unseal()ing the device again in the future. This call does not impact the current sealed/unsealed state of the device -- if currently unsealed, the device will remain in that state until Seal() is called or the device is unbound. Returns ZX_OK on success. Returns other errors if operations on the underlying block device return errors.

Request

NameType

Response

NameType
status zx/status

STRUCTS

CONSTANTS

NameValueTypeDescription
MAX_KEY_SIZE 256 uint32

We require simple layout to use the simple C bindings, and simple layout requires that we have non-maximal length bounds, so give some excessively large key length here so we can use the simple layout.