/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.hardware.keymaster@3.0;
/**
* Keymaster device definition. For thorough documentation see the implementer's reference, at
* https://source.android.com/security/keystore/implementer-ref.html
*/
interface IKeymasterDevice {
/**
* Returns information about the underlying keymaster hardware.
*
* @return isSecure is true if keys are stored and never leave secure hardware (Trusted
* Execution Environment or similar). CDD requires that all devices initially
* launched with Marshmallow or later must have secure hardware.
*
* @return supportsEllipticCurve is true if the hardware supports Elliptic Curve cryptography
* with the NIST curves (P-224, P-256, P-384, and P-521). CDD requires that all
* devices initially launched with Nougat or later must support Elliptic Curve
* cryptography.
*
* @return supportsSymmetricCryptography is true if the hardware supports symmetric
* cryptography, including AES and HMAC. CDD requires that all devices initially
* launched with Nougat or later must support hardware enforcement of Keymaster
* authorizations.
*
* @return supportsAttestation is true if the hardware supports generation of Keymaster public
* key attestation certificates, signed with a key injected in a secure
* environment. CDD requires that all devices initially launched with Android O or
* later must support hardware attestation.
*
* @return supportsAllDigests is true if the hardware supports all keymaster digest functions,
* namely ND-5, SHA-1, SHA-224, SHA-256, SHA-384 and SHA-512. CDD requires that all
* devices launched initially with Android O or later must support all digests.
*
* @return keymasterName is the name of the keymaster implementation.
*
* @return keymasterAuthorName is the name of the author of the keymaster implementation
* (generally this should be the name of an organization, not an individual.)
*/
getHardwareFeatures()
generates(bool isSecure, bool supportsEllipticCurve, bool supportsSymmetricCryptography,
bool supportsAttestation, bool supportsAllDigests, string keymasterName,
string keymasterAuthorName);
/**
* Adds entropy to the RNG used by keymaster. Entropy added through this method is guaranteed
* not to be the only source of entropy used, and the mixing function is required to be secure,
* in the sense that if the RNG is seeded (from any source) with any data the attacker cannot
* predict (or control), then the RNG output is indistinguishable from random. Thus, if the
* entropy from any source is good, the output must be good.
*
* @param data Bytes to be mixed into the RNG.
*
* @return error See the ErrorCode enum in types.hal.
*/
addRngEntropy(vec<uint8_t> data) generates(ErrorCode error);
/**
* Generates a key, or key pair, returning a key blob and/or a description of the key.
*
* @param keyParams Key generation parameters are defined as keymaster tag/value pairs, provided
* in params. See Tag in types.hal for the full list.
*
* @return error See the ErrorCode enum in types.hal.
*
* @return keyBlob Opaque, encrypted descriptor of the generated key, which generally contains a
* copy of the key material, wrapped in a key unavailable outside secure hardware.
*
* @return keyCharacteristics Description of the generated key. See KeyCharacteristis in
* types.hal.
*/
generateKey(vec<KeyParameter> keyParams)
generates(ErrorCode error, vec<uint8_t> keyBlob, KeyCharacteristics keyCharacteristics);
/**
* Imports a key, or key pair, returning a key blob and/or a description of the key.
*
* @param keyParams Key generation parameters are defined as keymaster tag/value pairs, provided
* in params. See Tag for the full list.
*
* @param keyFormat The format of the key material to import. See KeyFormat in types.hal.
*
* @pram keyData The key material to import, in the format specifed in keyFormat.
*
* @return error See the ErrorCode enum.
*
* @return keyBlob Opaque, encrypted descriptor of the generated key, which will generally
* contain a copy of the key material, wrapped in a key unavailable outside secure
* hardware.
*
* @return keyCharacteristics Decription of the generated key. See KeyCharacteristis.
*
* @return error See the ErrorCode enum.
*/
importKey(vec<KeyParameter> params, KeyFormat keyFormat, vec<uint8_t> keyData)
generates(ErrorCode error, vec<uint8_t> keyBlob, KeyCharacteristics keyCharacteristics);
/**
* Returns the characteristics of the specified key, if the keyBlob is valid (implementations
* must fully validate the integrity of the key).
*
* @param keyBlob The opaque descriptor returned by generateKey() or importKey();
*
* @param clientId An opaque byte string identifying the client. This value must match the
* Tag::APPLICATION_ID data provided during key generation/import. Without the
* correct value it must be cryptographically impossible for the secure hardware to
* obtain the key material.
*
* @param appData An opaque byte string provided by the application. This value must match the
* Tag::APPLICATION_DATA data provided during key generation/import. Without the
* correct value it must be cryptographically impossible for the secure hardware to
* obtain the key material.
*
* @return error See the ErrorCode enum in types.hal.
*
* @return keyCharacteristics Decription of the generated key. See KeyCharacteristis in
* types.hal.
*/
getKeyCharacteristics(vec<uint8_t> keyBlob, vec<uint8_t> clientId, vec<uint8_t> appData)
generates(ErrorCode error, KeyCharacteristics keyCharacteristics);
/**
* Exports a public key, returning the key in the specified format.
*
* @parm keyFormat The format used for export. See KeyFormat in types.hal.
*
* @param keyBlob The opaque descriptor returned by generateKey() or importKey(). The
* referenced key must be asymmetric.
*
* @param clientId An opaque byte string identifying the client. This value must match the
* Tag::APPLICATION_ID data provided during key generation/import. Without the
* correct value it must be cryptographically impossible for the secure hardware to
* obtain the key material.
*
* @param appData An opaque byte string provided by the application. This value must match the
* Tag::APPLICATION_DATA data provided during key generation/import. Without the
* correct value it must be cryptographically impossible for the secure hardware to
* obtain the key material.
*
* @return error See the ErrorCode enum in types.hal.
*
* @return keyMaterial The public key material in PKCS#8 format.
*/
exportKey(KeyFormat keyFormat, vec<uint8_t> keyBlob, vec<uint8_t> clientId,
vec<uint8_t> appData) generates(ErrorCode error, vec<uint8_t> keyMaterial);
/**
* Generates a signed X.509 certificate chain attesting to the presence of keyToAttest in
* keymaster. The certificate will contain an extension with OID 1.3.6.1.4.1.11129.2.1.17 and
* value defined in:
*
* https://developer.android.com/training/articles/security-key-attestation.html.
*
* @param keyToAttest The opaque descriptor returned by generateKey() or importKey(). The
* referenced key must be asymmetric.
*
* @param attestParams Parameters for the attestation, notably Tag::ATTESTATION_CHALLENGE.
*
* @return error See the ErrorCode enum in types.hal.
*/
attestKey(vec<uint8_t> keyToAttest, vec<KeyParameter> attestParams)
generates(ErrorCode error, vec<vec<uint8_t>> certChain);
/**
* Upgrades an old key. Keys can become "old" in two ways: Keymaster can be upgraded to a new
* version, or the system can be updated to invalidate the OS version and/or patch level. In
* either case, attempts to use an old key with getKeyCharacteristics(), exportKey(),
* attestKey() or begin() will result in keymaster returning
* ErrorCode::KEY_REQUIRES_UPGRADE. This method must then be called to upgrade the key.
*
* @param keyBlobToUpgrade The opaque descriptor returned by generateKey() or importKey();
*
* @param upgradeParams A parameter list containing any parameters needed to complete the
* upgrade, including Tag::APPLICATION_ID and Tag::APPLICATION_DATA.
*
* @return error See the ErrorCode enum.
*/
upgradeKey(vec<uint8_t> keyBlobToUpgrade, vec<KeyParameter> upgradeParams)
generates(ErrorCode error, vec<uint8_t> upgradedKeyBlob);
/**
* Deletes the key, or key pair, associated with the key blob. After calling this function it
* will be impossible to use the key for any other operations. May be applied to keys from
* foreign roots of trust (keys not usable under the current root of trust).
*
* This is a NOP for keys that don't have rollback protection.
*
* @param keyBlobToUpgrade The opaque descriptor returned by generateKey() or importKey();
*
* @return error See the ErrorCode enum.
*/
deleteKey(vec<uint8_t> keyBlob) generates(ErrorCode error);
/**
* Deletes all keys in the hardware keystore. Used when keystore is reset completely. After
* calling this function it will be impossible to use any previously generated or imported key
* blobs for any operations.
*
* This is a NOP if keys don't have rollback protection.
*
* @return error See the ErrorCode enum.
*/
deleteAllKeys() generates(ErrorCode error);
/**
* Destroys knowledge of the device's ids. This prevents all device id attestation in the
* future. The destruction must be permanent so that not even a factory reset will restore the
* device ids.
*
* Device id attestation may be provided only if this method is fully implemented, allowing the
* user to permanently disable device id attestation. If this cannot be guaranteed, the device
* must never attest any device ids.
*
* This is a NOP if device id attestation is not supported.
*
* @return error See the ErrorCode enum.
*/
destroyAttestationIds() generates(ErrorCode error);
/**
* Begins a cryptographic operation using the specified key. If all is well, begin() will return
* ErrorCode::OK and create an operation handle which must be passed to subsequent calls to
* update(), finish() or abort().
*
* It is critical that each call to begin() be paired with a subsequent call to finish() or
* abort(), to allow the keymaster implementation to clean up any internal operation state.
* Failure to do this may leak internal state space or other internal resources and may
* eventually cause begin() to return ErrorCode::TOO_MANY_OPERATIONS when it runs out of space
* for operations. Any result other than ErrorCode::OK from begin(), update() or finish()
* implicitly aborts the operation, in which case abort() need not be called (and will return
* ErrorCode::INVALID_OPERATION_HANDLE if called).
*
* @param purpose The purpose of the operation, one of KeyPurpose::ENCRYPT, KeyPurpose::DECRYPT,
* KeyPurpose::SIGN or KeyPurpose::VERIFY. Note that for AEAD modes, encryption and
* decryption imply signing and verification, respectively, but must be specified as
* KeyPurpose::ENCRYPT and KeyPurpose::DECRYPT.
*
* @param keyBlob The opaque key descriptor returned by generateKey() or importKey(). The key
* must have a purpose compatible with purpose and all of its usage requirements
* must be satisfied, or begin() will return an appropriate error code.
*
* @param inParams Additional parameters for the operation. This is typically used to provide
* authentication data, with Tag::AUTH_TOKEN. If Tag::APPLICATION_ID or
* Tag::APPLICATION_DATA were provided during generation, they must be provided
* here, or the operation will fail with ErrorCode::INVALID_KEY_BLOB. For operations
* that require a nonce or IV, on keys that were generated with Tag::CALLER_NONCE,
* inParams may contain a tag Tag::NONCE.
*
* @return error See the ErrorCode enum in types.hal.
*
* @return outParams Output parameters. Used to return additional data from the operation
* initialization, notably to return the IV or nonce from operations that generate
* an IV or nonce.
*
* @return operationHandle The newly-created operation handle which must be passed to update(),
* finish() or abort().
*/
begin(KeyPurpose purpose, vec<uint8_t> key, vec<KeyParameter> inParams)
generates(ErrorCode error, vec<KeyParameter> outParams, OperationHandle operationHandle);
/**
* Provides data to, and possibly receives output from, an ongoing cryptographic operation begun
* with begin().
*
* If operationHandle is invalid, update() will return ErrorCode::INVALID_OPERATION_HANDLE.
*
* update() may not consume all of the data provided in the data buffer. update() will return
* the amount consumed in inputConsumed. The caller may provide the unconsumed data in a
* subsequent call.
*
* @param operationHandle The operation handle returned by begin().
*
* @param inParams Additional parameters for the operation. For AEAD modes, this is used to
* specify Tag::ADDITIONAL_DATA. Note that additional data may be provided in
* multiple calls to update(), but only until input data has been provided.
*
* @param input Data to be processed, per the parameters established in the call to begin().
* Note that update() may or may not consume all of the data provided. See
* inputConsumed.
*
* @return error See the ErrorCode enum in types.hal.
*
* @return inputConsumed Amount of data that was consumed by update(). If this is less than the
* amount provided, the caller may provide the remainder in a subsequent call to
* update() or finish().
*
* @return outParams Output parameters, used to return additional data from the operation The
* caller takes ownership of the output parameters array and must free it with
* keymaster_free_param_set().
*
* @return output The output data, if any.
*/
update(OperationHandle operationHandle, vec<KeyParameter> inParams, vec<uint8_t> input)
generates(ErrorCode error, uint32_t inputConsumed, vec<KeyParameter> outParams,
vec<uint8_t> output);
/**
* Finalizes a cryptographic operation begun with begin() and invalidates operationHandle.
*
* @param operationHandle The operation handle returned by begin(). This handle will be
* invalid when finish() returns.
*
* @param inParams Additional parameters for the operation. For AEAD modes, this is used to
* specify Tag::ADDITIONAL_DATA, but only if no input data was provided to update().
*
* @param input Data to be processed, per the parameters established in the call to
* begin(). finish() must consume all provided data or return
* ErrorCode::INVALID_INPUT_LENGTH.
*
* @param signature The signature to be verified if the purpose specified in the begin() call
* was KeyPurpose::VERIFY.
*
* @return error See the ErrorCode enum in types.hal.
*
* @return outParams Any output parameters generated by finish().
*
* @return output The output data, if any.
*/
finish(OperationHandle operationHandle, vec<KeyParameter> inParams, vec<uint8_t> input,
vec<uint8_t> signature)
generates(ErrorCode error, vec<KeyParameter> outParams, vec<uint8_t> output);
/**
* Aborts a cryptographic operation begun with begin(), freeing all internal resources and
* invalidating operationHandle.
*
* @param operationHandle The operation handle returned by begin(). This handle will be
* invalid when abort() returns.
*
* @return error See the ErrorCode enum in types.hal.
*/
abort(OperationHandle operationHandle) generates(ErrorCode error);
};