3080276974
Key agreement (ECDH) has been punted from the N release, and a configuration method has been added to support version binding. Change-Id: Ia4aeee1bd7ab88cda3b9faa653470e608aa55942
432 lines
22 KiB
C
432 lines
22 KiB
C
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ANDROID_HARDWARE_KEYMASTER2_H
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#define ANDROID_HARDWARE_KEYMASTER2_H
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#include <hardware/keymaster_common.h>
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#include <hardware/keymaster_defs.h>
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__BEGIN_DECLS
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/**
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* Keymaster2 device definition
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*/
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struct keymaster2_device {
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/**
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* Common methods of the keymaster device. This *must* be the first member of
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* keymaster_device as users of this structure will cast a hw_device_t to
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* keymaster_device pointer in contexts where it's known the hw_device_t references a
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* keymaster_device.
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*/
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struct hw_device_t common;
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void* context;
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/**
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* See flags defined for keymaster0_devices::flags in keymaster_common.h. Used only for
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* backward compatibility; keymaster2 hardware devices must set this to zero.
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*/
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uint32_t flags;
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/**
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* Configures keymaster. This method must be called once after the device is opened and before
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* it is used. It's used to provide KM_TAG_OS_VERSION and KM_TAG_OS_PATCHLEVEL to keymaster.
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* Until this method is called, all other methods will return KM_ERROR_KEYMASTER_NOT_CONFIGURED.
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* The values provided by this method are only accepted by keymaster once per boot. Subsequent
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* calls will return KM_ERROR_OK, but do nothing.
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*
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* If the keymaster implementation is in secure hardware and the OS version and patch level
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* values provided do not match the values provided to the secure hardware by the bootloader (or
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* if the bootloader did not provide values), then this method will return
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* KM_ERROR_INVALID_ARGUMENT, and all other methods will continue returning
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* KM_ERROR_KEYMASTER_NOT_CONFIGURED.
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*/
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keymaster_error_t (*configure)(const struct keymaster2_device* dev,
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const keymaster_key_param_set_t* params);
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/**
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* Adds entropy to the RNG used by keymaster. Entropy added through this method is guaranteed
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* not to be the only source of entropy used, and the mixing function is required to be secure,
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* in the sense that if the RNG is seeded (from any source) with any data the attacker cannot
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* predict (or control), then the RNG output is indistinguishable from random. Thus, if the
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* entropy from any source is good, the output will be good.
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] data Random data to be mixed in.
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*
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* \param[in] data_length Length of \p data.
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*/
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keymaster_error_t (*add_rng_entropy)(const struct keymaster2_device* dev, const uint8_t* data,
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size_t data_length);
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/**
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* Generates a key, or key pair, returning a key blob and/or a description of the key.
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*
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* Key generation parameters are defined as keymaster tag/value pairs, provided in \p params.
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* See keymaster_tag_t for the full list. Some values that are always required for generation
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* of useful keys are:
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*
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* - KM_TAG_ALGORITHM;
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* - KM_TAG_PURPOSE; and
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* - (KM_TAG_USER_SECURE_ID and KM_TAG_USER_AUTH_TYPE) or KM_TAG_NO_AUTH_REQUIRED.
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*
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* KM_TAG_AUTH_TIMEOUT should generally be specified unless KM_TAG_NO_AUTH_REQUIRED is present,
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* or the user will have to authenticate for every use.
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*
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* KM_TAG_BLOCK_MODE, KM_TAG_PADDING, KM_TAG_MAC_LENGTH and KM_TAG_DIGEST must be specified for
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* algorithms that require them.
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*
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* The following tags may not be specified; their values will be provided by the implementation.
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*
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* - KM_TAG_ORIGIN,
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* - KM_TAG_ROLLBACK_RESISTANT,
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* - KM_TAG_CREATION_DATETIME
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] params Array of key generation param
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*
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* \param[out] key_blob returns the generated key. \p key_blob must not be NULL. The caller
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* assumes ownership key_blob->key_material and must free() it.
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*
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* \param[out] characteristics returns the characteristics of the key that was, generated, if
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* non-NULL. If non-NULL, the caller assumes ownership and must deallocate with
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* keymaster_free_characteristics(). Note that KM_TAG_ROOT_OF_TRUST, KM_TAG_APPLICATION_ID and
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* KM_TAG_APPLICATION_DATA are never returned.
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*/
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keymaster_error_t (*generate_key)(const struct keymaster2_device* dev,
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const keymaster_key_param_set_t* params,
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keymaster_key_blob_t* key_blob,
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keymaster_key_characteristics_t* characteristics);
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/**
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* Returns the characteristics of the specified key, or KM_ERROR_INVALID_KEY_BLOB if the
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* key_blob is invalid (implementations must fully validate the integrity of the key).
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* client_id and app_data must be the ID and data provided when the key was generated or
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* imported, or empty if KM_TAG_APPLICATION_ID and/or KM_TAG_APPLICATION_DATA were not provided
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* during generation. Those values are not included in the returned characteristics. The
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* caller assumes ownership of the allocated characteristics object, which must be deallocated
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* with keymaster_free_characteristics().
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*
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* Note that KM_TAG_APPLICATION_ID and KM_TAG_APPLICATION_DATA are never returned.
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] key_blob The key to retreive characteristics from.
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*
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* \param[in] client_id The client ID data, or NULL if none associated.
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*
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* \param[in] app_id The app data, or NULL if none associated.
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*
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* \param[out] characteristics The key characteristics. Must not be NULL. The caller assumes
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* ownership of the contents and must deallocate with keymaster_free_characteristics().
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*/
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keymaster_error_t (*get_key_characteristics)(const struct keymaster2_device* dev,
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const keymaster_key_blob_t* key_blob,
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const keymaster_blob_t* client_id,
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const keymaster_blob_t* app_data,
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keymaster_key_characteristics_t* characteristics);
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/**
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* Imports a key, or key pair, returning a key blob and/or a description of the key.
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*
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* Most key import parameters are defined as keymaster tag/value pairs, provided in "params".
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* See keymaster_tag_t for the full list. Values that are always required for import of useful
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* keys are:
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*
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* - KM_TAG_ALGORITHM;
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* - KM_TAG_PURPOSE; and
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* - (KM_TAG_USER_SECURE_ID and KM_TAG_USER_AUTH_TYPE) or KM_TAG_NO_AUTH_REQUIRED.
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*
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* KM_TAG_AUTH_TIMEOUT should generally be specified. If unspecified, the user will have to
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* authenticate for every use.
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*
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* The following tags will take default values if unspecified:
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*
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* - KM_TAG_KEY_SIZE will default to the size of the key provided.
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* - KM_TAG_RSA_PUBLIC_EXPONENT will default to the value in the key provided (for RSA keys)
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*
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* The following tags may not be specified; their values will be provided by the implementation.
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*
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* - KM_TAG_ORIGIN,
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* - KM_TAG_ROLLBACK_RESISTANT,
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* - KM_TAG_CREATION_DATETIME
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] params Parameters defining the imported key.
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*
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* \param[in] params_count The number of entries in \p params.
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*
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* \param[in] key_format specifies the format of the key data in key_data.
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*
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* \param[out] key_blob Used to return the opaque key blob. Must be non-NULL. The caller
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* assumes ownership of the contained key_material.
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*
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* \param[out] characteristics Used to return the characteristics of the imported key. May be
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* NULL, in which case no characteristics will be returned. If non-NULL, the caller assumes
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* ownership of the contents and must deallocate with keymaster_free_characteristics(). Note
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* that KM_TAG_APPLICATION_ID and KM_TAG_APPLICATION_DATA are never returned.
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*/
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keymaster_error_t (*import_key)(const struct keymaster2_device* dev,
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const keymaster_key_param_set_t* params,
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keymaster_key_format_t key_format,
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const keymaster_blob_t* key_data,
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keymaster_key_blob_t* key_blob,
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keymaster_key_characteristics_t* characteristics);
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/**
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* Exports a public or symmetric key, returning a byte array in the specified format.
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*
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* Note that symmetric key export is allowed only if the key was created with KM_TAG_EXPORTABLE,
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* and only if all of the requirements for key usage (e.g. authentication) are met.
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] export_format The format to be used for exporting the key.
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*
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* \param[in] key_to_export The key to export.
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*
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* \param[in] client_id Client ID blob, which must match the blob provided in
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* KM_TAG_APPLICATION_ID during key generation (if any).
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*
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* \param[in] app_data Appliation data blob, which must match the blob provided in
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* KM_TAG_APPLICATION_DATA during key generation (if any).
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*
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* \param[out] export_data The exported key material. The caller assumes ownership.
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*/
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keymaster_error_t (*export_key)(const struct keymaster2_device* dev,
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keymaster_key_format_t export_format,
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const keymaster_key_blob_t* key_to_export,
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const keymaster_blob_t* client_id,
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const keymaster_blob_t* app_data,
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keymaster_blob_t* export_data);
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/**
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* Generates a signed X.509 certificate chain attesting to the presence of \p key_to_attest in
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* keymaster (TODO(swillden): Describe certificate contents in more detail). The certificate
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* will contain an extension with OID 1.3.6.1.4.1.11129.2.1.17 and value defined in
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* <TODO:swillden -- insert link here> which contains the key description.
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] key_to_attest The keymaster key for which the attestation certificate will be
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* generated.
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*
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* \param[in] attest_params Parameters defining how to do the attestation. At present the only
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* parameter is KM_TAG_ALGORITHM, which must be either KM_ALGORITHM_EC or KM_ALGORITHM_RSA.
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* This selects which of the provisioned attestation keys will be used to sign the certificate.
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*
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* \param[out] cert_chain An array of DER-encoded X.509 certificates. The first will be the
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* certificate for \p key_to_attest. The remaining entries will chain back to the root. The
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* caller takes ownership and must deallocate with keymaster_free_cert_chain.
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*/
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keymaster_error_t (*attest_key)(const struct keymaster2_device* dev,
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const keymaster_key_blob_t* key_to_attest,
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const keymaster_key_param_set_t* attest_params,
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keymaster_cert_chain_t* cert_chain);
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/**
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* Upgrades an old key. Keys can become "old" in two ways: Keymaster can be upgraded to a new
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* version, or the system can be updated to invalidate the OS version and/or patch level. In
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* either case, attempts to use an old key will result in keymaster returning
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* KM_ERROR_KEY_REQUIRES_UPGRADE. This method should then be called to upgrade the key.
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] key_to_upgrade The keymaster key to upgrade.
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*
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* \param[in] upgrade_params Parameters needed to complete the upgrade. In particular,
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* KM_TAG_APPLICATION_ID and KM_TAG_APPLICATION_DATA will be required if they were defined for
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* the key.
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*
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* \param[out] upgraded_key The upgraded key blob.
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*/
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keymaster_error_t (*upgrade_key)(const struct keymaster2_device* dev,
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const keymaster_key_blob_t* key_to_upgrade,
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const keymaster_key_param_set_t* upgrade_params,
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keymaster_key_blob_t* upgraded_key);
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/**
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* Deletes the key, or key pair, associated with the key blob. After calling this function it
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* will be impossible to use the key for any other operations. May be applied to keys from
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* foreign roots of trust (keys not usable under the current root of trust).
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*
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* This function is optional and should be set to NULL if it is not implemented.
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] key The key to be deleted.
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*/
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keymaster_error_t (*delete_key)(const struct keymaster2_device* dev,
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const keymaster_key_blob_t* key);
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/**
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* Deletes all keys in the hardware keystore. Used when keystore is reset completely. After
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* calling this function it will be impossible to use any previously generated or imported key
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* blobs for any operations.
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*
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* This function is optional and should be set to NULL if it is not implemented.
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*
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* \param[in] dev The keymaster device structure.
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*/
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keymaster_error_t (*delete_all_keys)(const struct keymaster2_device* dev);
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/**
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* Begins a cryptographic operation using the specified key. If all is well, begin() will
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* return KM_ERROR_OK and create an operation handle which must be passed to subsequent calls to
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* update(), finish() or abort().
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*
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* It is critical that each call to begin() be paired with a subsequent call to finish() or
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* abort(), to allow the keymaster implementation to clean up any internal operation state.
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* Failure to do this may leak internal state space or other internal resources and may
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* eventually cause begin() to return KM_ERROR_TOO_MANY_OPERATIONS when it runs out of space for
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* operations. Any result other than KM_ERROR_OK from begin(), update() or finish() implicitly
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* aborts the operation, in which case abort() need not be called (and will return
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* KM_ERROR_INVALID_OPERATION_HANDLE if called).
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] purpose The purpose of the operation, one of KM_PURPOSE_ENCRYPT,
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* KM_PURPOSE_DECRYPT, KM_PURPOSE_SIGN or KM_PURPOSE_VERIFY. Note that for AEAD modes,
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* encryption and decryption imply signing and verification, respectively, but should be
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* specified as KM_PURPOSE_ENCRYPT and KM_PURPOSE_DECRYPT.
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*
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* \param[in] key The key to be used for the operation. \p key must have a purpose compatible
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* with \p purpose and all of its usage requirements must be satisfied, or begin() will return
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* an appropriate error code.
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*
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* \param[in] in_params Additional parameters for the operation. This is typically used to
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* provide authentication data, with KM_TAG_AUTH_TOKEN. If KM_TAG_APPLICATION_ID or
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* KM_TAG_APPLICATION_DATA were provided during generation, they must be provided here, or the
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* operation will fail with KM_ERROR_INVALID_KEY_BLOB. For operations that require a nonce or
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* IV, on keys that were generated with KM_TAG_CALLER_NONCE, in_params may contain a tag
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* KM_TAG_NONCE.
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*
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* \param[out] out_params Output parameters. Used to return additional data from the operation
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* initialization, notably to return the IV or nonce from operations that generate an IV or
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* nonce. The caller takes ownership of the output parameters array and must free it with
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* keymaster_free_param_set(). out_params may be set to NULL if no output parameters are
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* expected. If out_params is NULL, and output paramaters are generated, begin() will return
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* KM_ERROR_OUTPUT_PARAMETER_NULL.
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*
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* \param[out] operation_handle The newly-created operation handle which must be passed to
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* update(), finish() or abort(). If operation_handle is NULL, begin() will return
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* KM_ERROR_OUTPUT_PARAMETER_NULL.
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*/
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keymaster_error_t (*begin)(const struct keymaster2_device* dev, keymaster_purpose_t purpose,
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const keymaster_key_blob_t* key,
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const keymaster_key_param_set_t* in_params,
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keymaster_key_param_set_t* out_params,
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keymaster_operation_handle_t* operation_handle);
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/**
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* Provides data to, and possibly receives output from, an ongoing cryptographic operation begun
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* with begin().
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*
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* If operation_handle is invalid, update() will return KM_ERROR_INVALID_OPERATION_HANDLE.
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*
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* update() may not consume all of the data provided in the data buffer. update() will return
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* the amount consumed in *data_consumed. The caller should provide the unconsumed data in a
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* subsequent call.
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] operation_handle The operation handle returned by begin().
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*
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* \param[in] in_params Additional parameters for the operation. For AEAD modes, this is used
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* to specify KM_TAG_ADDITIONAL_DATA. Note that additional data may be provided in multiple
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* calls to update(), but only until input data has been provided.
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*
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* \param[in] input Data to be processed, per the parameters established in the call to begin().
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* Note that update() may or may not consume all of the data provided. See \p input_consumed.
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*
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* \param[out] input_consumed Amount of data that was consumed by update(). If this is less
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* than the amount provided, the caller should provide the remainder in a subsequent call to
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* update().
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*
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* \param[out] out_params Output parameters. Used to return additional data from the operation
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* The caller takes ownership of the output parameters array and must free it with
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* keymaster_free_param_set(). out_params may be set to NULL if no output parameters are
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* expected. If out_params is NULL, and output paramaters are generated, begin() will return
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* KM_ERROR_OUTPUT_PARAMETER_NULL.
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*
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* \param[out] output The output data, if any. The caller assumes ownership of the allocated
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* buffer. output must not be NULL.
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*
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* Note that update() may not provide any output, in which case output->data_length will be
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* zero, and output->data may be either NULL or zero-length (so the caller should always free()
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* it).
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*/
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keymaster_error_t (*update)(const struct keymaster2_device* dev,
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keymaster_operation_handle_t operation_handle,
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const keymaster_key_param_set_t* in_params,
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const keymaster_blob_t* input, size_t* input_consumed,
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keymaster_key_param_set_t* out_params, keymaster_blob_t* output);
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/**
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* Finalizes a cryptographic operation begun with begin() and invalidates \p operation_handle.
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*
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* \param[in] dev The keymaster device structure.
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*
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* \param[in] operation_handle The operation handle returned by begin(). This handle will be
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* invalidated.
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*
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* \param[in] in_params Additional parameters for the operation. For AEAD modes, this is used
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* to specify KM_TAG_ADDITIONAL_DATA, but only if no input data was provided to update().
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*
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* \param[in] input Data to be processed, per the parameters established in the call to
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* begin(). finish() must consume all provided data or return KM_ERROR_INVALID_INPUT_LENGTH.
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*
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* \param[in] signature The signature to be verified if the purpose specified in the begin()
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* call was KM_PURPOSE_VERIFY.
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*
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* \param[out] output The output data, if any. The caller assumes ownership of the allocated
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* buffer.
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*
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* If the operation being finished is a signature verification or an AEAD-mode decryption and
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* verification fails then finish() will return KM_ERROR_VERIFICATION_FAILED.
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*/
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keymaster_error_t (*finish)(const struct keymaster2_device* dev,
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keymaster_operation_handle_t operation_handle,
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const keymaster_key_param_set_t* in_params,
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const keymaster_blob_t* input, const keymaster_blob_t* signature,
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keymaster_key_param_set_t* out_params, keymaster_blob_t* output);
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/**
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* Aborts a cryptographic operation begun with begin(), freeing all internal resources and
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* invalidating \p operation_handle.
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*/
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keymaster_error_t (*abort)(const struct keymaster2_device* dev,
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keymaster_operation_handle_t operation_handle);
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};
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typedef struct keymaster2_device keymaster2_device_t;
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/* Convenience API for opening and closing keymaster devices */
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static inline int keymaster2_open(const struct hw_module_t* module, keymaster2_device_t** device) {
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return module->methods->open(module, KEYSTORE_KEYMASTER, (struct hw_device_t**)device);
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}
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static inline int keymaster2_close(keymaster2_device_t* device) {
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return device->common.close(&device->common);
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}
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__END_DECLS
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#endif // ANDROID_HARDWARE_KEYMASTER2_H
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