From 70335f3d30cf32a6f0352b75430aa6474821399d Mon Sep 17 00:00:00 2001 From: Shawn Willden Date: Wed, 8 Jul 2015 09:57:16 -0600 Subject: Correct keymaster1 documentation. Bug: 22291207 Change-Id: I130d2ab2110321dc2228d41a154750da3a3f0b75 --- include/hardware/keymaster1.h | 160 ++++++++++++++++---------------------- include/hardware/keymaster_defs.h | 3 +- 2 files changed, 66 insertions(+), 97 deletions(-) diff --git a/include/hardware/keymaster1.h b/include/hardware/keymaster1.h index 77243af..afd202c 100644 --- a/include/hardware/keymaster1.h +++ b/include/hardware/keymaster1.h @@ -250,11 +250,8 @@ struct keymaster1_device { * of useful keys are: * * - KM_TAG_ALGORITHM; - * - KM_TAG_PURPOSE; - * - KM_TAG_USER_ID or KM_TAG_ALL_USERS; - * - KM_TAG_USER_AUTH_ID or KM_TAG_NO_AUTH_REQUIRED; - * - KM_TAG_APPLICATION_ID or KM_TAG_ALL_APPLICATIONS; and - * - KM_TAG_ORIGINATION_EXPIRE_DATETIME + * - KM_TAG_PURPOSE; and + * - (KM_TAG_USER_SECURE_ID and KM_TAG_USER_AUTH_TYPE) or KM_TAG_NO_AUTH_REQUIRED. * * KM_TAG_AUTH_TIMEOUT should generally be specified unless KM_TAG_NO_AUTH_REQUIRED is present, * or the user will have to authenticate for every use. @@ -262,25 +259,11 @@ struct keymaster1_device { * KM_TAG_BLOCK_MODE, KM_TAG_PADDING, KM_TAG_MAC_LENGTH and KM_TAG_DIGEST must be specified for * algorithms that require them. * - * The following tags will take default values if unspecified: - * - * - KM_TAG_KEY_SIZE defaults to a recommended key size for the specified algorithm. - * - * - KM_TAG_USAGE_EXPIRE_DATETIME defaults to the value of KM_TAG_ORIGINATION_EXPIRE_DATETIME. - * - * - KM_TAG_ACTIVE_DATETIME will default to the value of KM_TAG_CREATION_DATETIME - * - * - KM_TAG_ROOT_OF_TRUST will default to the current root of trust. - * - * - KM_TAG_{RSA|DSA|DH}_* will default to values appropriate for the specified key size. - * * The following tags may not be specified; their values will be provided by the implementation. * * - KM_TAG_ORIGIN, - * * - KM_TAG_ROLLBACK_RESISTANT, - * - * - KM_TAG_CREATION_DATETIME, + * - KM_TAG_CREATION_DATETIME * * \param[in] dev The keymaster device structure. * @@ -288,12 +271,11 @@ struct keymaster1_device { * * \param[in] params_count Length of \p params. * - * \param[out] key_blob returns the generated key. If \p key_blob is NULL, no key is generated, - * but the characteristics of the key that would be generated are returned. The caller assumes - * ownership key_blob->key_material and must free() it. + * \param[out] key_blob returns the generated key. \p key_blob must not be NULL. The caller + * assumes ownership key_blob->key_material and must free() it. * - * \param[out] characteristics returns the characteristics of the key that was, or would be, - * generated, if non-NULL. The caller assumes ownership, and the object must be freed with + * \param[out] characteristics returns the characteristics of the key that was, generated, if + * non-NULL. If non-NULL, the caller assumes ownership and must deallocate with * keymaster_free_characteristics(). Note that KM_TAG_ROOT_OF_TRUST, KM_TAG_APPLICATION_ID and * KM_TAG_APPLICATION_DATA are never returned. */ @@ -303,11 +285,13 @@ struct keymaster1_device { keymaster_key_characteristics_t** characteristics); /** - * Returns the characteristics of the specified key, or NULL if the key_blob is invalid - * (implementations must fully validate the integrity of the key). client_id and app_data must - * be the ID and data provided when the key was generated or imported. Those values are not - * included in the returned characteristics. Caller assumes ownership of the allocated - * characteristics object, which must be deallocated with keymaster_free_characteristics(). + * Returns the characteristics of the specified key, or KM_ERROR_INVALID_KEY_BLOB if the + * key_blob is invalid (implementations must fully validate the integrity of the key). + * client_id and app_data must be the ID and data provided when the key was generated or + * imported, or empty if KM_TAG_APPLICATION_ID and/or KM_TAG_APPLICATION_DATA were not provided + * during generation. Those values are not included in the returned characteristics. The + * caller assumes ownership of the allocated characteristics object, which must be deallocated + * with keymaster_free_characteristics(). * * Note that KM_TAG_ROOT_OF_TRUST, KM_TAG_APPLICATION_ID and KM_TAG_APPLICATION_DATA are never * returned. @@ -332,38 +316,26 @@ struct keymaster1_device { * Imports a key, or key pair, returning a key blob and/or a description of the key. * * Most key import parameters are defined as keymaster tag/value pairs, provided in "params". - * See keymaster_tag_t for the full list. Some values that are always required for import of - * useful keys are: + * See keymaster_tag_t for the full list. Values that are always required for import of useful + * keys are: * - * - KM_TAG_PURPOSE; - * - * - KM_TAG_USER_ID - * - * - KM_TAG_USER_AUTH_ID; - * - * - KM_TAG_APPLICATION_ID or KM_TAG_ALL_APPLICATIONS; - * - * - KM_TAG_PRIVKEY_EXPIRE_DATETIME. + * - KM_TAG_ALGORITHM; + * - KM_TAG_PURPOSE; and + * - (KM_TAG_USER_SECURE_ID and KM_TAG_USER_AUTH_TYPE) or KM_TAG_NO_AUTH_REQUIRED. * * KM_TAG_AUTH_TIMEOUT should generally be specified. If unspecified, the user will have to - * authenticate for every use, unless KM_TAG_USER_AUTH_ID is set to - * KM_NO_AUTHENTICATION_REQUIRED. + * authenticate for every use. * * The following tags will take default values if unspecified: * - * - KM_TAG_PUBKEY_EXPIRE_DATETIME will default to the value for KM_TAG_PRIVKEY_EXPIRE_DATETIME. - * - * - KM_TAG_ACTIVE_DATETIME will default to the value of KM_TAG_CREATION_DATETIME - * - * - KM_TAG_ROOT_OF_TRUST will default to the current root of trust. + * - KM_TAG_KEY_SIZE will default to the size of the key provided. + * - KM_TAG_RSA_PUBLIC_EXPONENT will default to the value in the key provided (for RSA keys) * * The following tags may not be specified; their values will be provided by the implementation. * * - KM_TAG_ORIGIN, - * * - KM_TAG_ROLLBACK_RESISTANT, - * - * - KM_TAG_CREATION_DATETIME, + * - KM_TAG_CREATION_DATETIME * * \param[in] dev The keymaster device structure. * @@ -378,7 +350,9 @@ struct keymaster1_device { * * \param[out] characteristics Used to return the characteristics of the imported key. May be * NULL, in which case no characteristics will be returned. If non-NULL, the caller assumes - * ownership and must deallocate with keymaster_free_characteristics(). + * ownership and must deallocate with keymaster_free_characteristics(). Note that + * KM_TAG_ROOT_OF_TRUST, KM_TAG_APPLICATION_ID and + * KM_TAG_APPLICATION_DATA are never returned. */ keymaster_error_t (*import_key)(const struct keymaster1_device* dev, const keymaster_key_param_set_t* params, @@ -439,37 +413,40 @@ struct keymaster1_device { * * 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 will leak internal state space or other internal resources and will + * Failure to do this may leak internal state space or other internal resources and may * eventually cause begin() to return KM_ERROR_TOO_MANY_OPERATIONS when it runs out of space for - * operations. + * operations. Any result other than KM_ERROR_OK from begin(), update() or finish() implicitly + * aborts the operation, in which case abort() need not be called (and will return + * KM_ERROR_INVALID_OPERATION_HANDLE if called). * * \param[in] dev The keymaster device structure. * * \param[in] purpose The purpose of the operation, one of KM_PURPOSE_ENCRYPT, * KM_PURPOSE_DECRYPT, KM_PURPOSE_SIGN or KM_PURPOSE_VERIFY. Note that for AEAD modes, - * encryption and decryption imply signing and verification, respectively. + * encryption and decryption imply signing and verification, respectively, but should be + * specified as KM_PURPOSE_ENCRYPT and KM_PURPOSE_DECRYPT. * * \param[in] key The key to be used for the operation. \p key must have a purpose compatible * with \p purpose and all of its usage requirements must be satisfied, or begin() will return * an appropriate error code. * - * \param[in] params Additional parameters for the operation. This is typically used to provide - * client ID information, with tags KM_TAG_APPLICATION_ID and KM_TAG_APPLICATION_DATA. If the - * client information associated with the key is not provided, begin() will fail and return - * KM_ERROR_INVALID_KEY_BLOB. For operations that require a nonce or IV, this must contain a - * tag KM_TAG_NONCE. For AEAD operations KM_TAG_CHUNK_SIZE is specified here. - * - * \param[in] params_count The number of entries in \p params. - * - * \param[out] out_params Array of output parameters. The caller takes ownership of the output - * parametes array and must free it. out_params may be set to NULL if no output parameters are - * expected. If NULL, and output paramaters are generated, begin() will return + * \param[in] in_params Additional parameters for the operation. This is typically used to + * provide authentication data, with KM_TAG_AUTH_TOKEN. If KM_TAG_APPLICATION_ID or + * KM_TAG_APPLICATION_DATA were provided during generation, they must be provided here, or the + * operation will fail with KM_ERROR_INVALID_KEY_BLOB. For operations that require a nonce or + * IV, on keys that were generated with KM_TAG_CALLER_NONCE, in_params may contain a tag + * KM_TAG_NONCE. For AEAD operations KM_TAG_CHUNK_SIZE is specified here. + * + * \param[out] out_params 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. The caller takes ownership of the output parameters array and must free it with + * keymaster_free_param_set(). out_params may be set to NULL if no output parameters are + * expected. If out_params is NULL, and output paramaters are generated, begin() will return * KM_ERROR_OUTPUT_PARAMETER_NULL. * - * \param[out] out_params_count The length of out_params. - * * \param[out] operation_handle The newly-created operation handle which must be passed to - * update(), finish() or abort(). + * update(), finish() or abort(). If operation_handle is NULL, begin() will return + * KM_ERROR_OUTPUT_PARAMETER_NULL. */ keymaster_error_t (*begin)(const struct keymaster1_device* dev, keymaster_purpose_t purpose, const keymaster_key_blob_t* key, @@ -483,37 +460,37 @@ struct keymaster1_device { * * If operation_handle is invalid, update() will return KM_ERROR_INVALID_OPERATION_HANDLE. * - * Not all of the data provided in the data buffer may be consumed. update() will return the - * amount consumed in *data_consumed. The caller should provide the unconsumed data in a + * update() may not consume all of the data provided in the data buffer. update() will return + * the amount consumed in *data_consumed. The caller should provide the unconsumed data in a * subsequent call. * * \param[in] dev The keymaster device structure. * * \param[in] operation_handle The operation handle returned by begin(). * - * \param[in] params Additional parameters for the operation. For AEAD modes, this is used to - * specify KM_TAG_ADDITIONAL_DATA. - * - * \param[in] params_count Length of \p params. + * \param[in] in_params Additional parameters for the operation. For AEAD modes, this is used + * to specify KM_TAG_ADDITIONAL_DATA. Note that additional data may be provided in multiple + * calls to update(), but only until input data has been provided. * * \param[in] 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 \p data_consumed. - * - * \param[in] input_length Length of \p input. + * Note that update() may or may not consume all of the data provided. See \p input_consumed. * * \param[out] input_consumed Amount of data that was consumed by update(). If this is less * than the amount provided, the caller should provide the remainder in a subsequent call to * update(). * - * \param[out] output The output data, if any. The caller assumes ownership of the allocated - * buffer. If output is NULL then NO input data is consumed and no output is produced, but - * *output_length is set to an estimate of the size that would have been produced by this - * update() and a subsequent finish(). + * \param[out] out_params 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(). out_params may be set to NULL if no output parameters are + * expected. If out_params is NULL, and output paramaters are generated, begin() will return + * KM_ERROR_OUTPUT_PARAMETER_NULL. * - * \param[out] output_length The length of the output buffer. + * \param[out] output The output data, if any. The caller assumes ownership of the allocated + * buffer. output must not be NULL. * - * Note that update() may not provide any output, in which case *output_length will be zero, and - * *output may be either NULL or zero-length (so the caller should always free() it). + * Note that update() may not provide any output, in which case output->data_length will be + * zero, and output->data may be either NULL or zero-length (so the caller should always free() + * it). */ keymaster_error_t (*update)(const struct keymaster1_device* dev, keymaster_operation_handle_t operation_handle, @@ -522,8 +499,7 @@ struct keymaster1_device { keymaster_key_param_set_t* out_params, keymaster_blob_t* output); /** - * Finalizes a cryptographic operation begun with begin() and invalidates operation_handle - * (except in the insufficient buffer case, detailed below). + * Finalizes a cryptographic operation begun with begin() and invalidates \p operation_handle. * * \param[in] dev The keymaster device structure. * @@ -531,20 +507,14 @@ struct keymaster1_device { * invalidated. * * \param[in] params Additional parameters for the operation. For AEAD modes, this is used to - * specify KM_TAG_ADDITIONAL_DATA. - * - * \param[in] params_count Length of \p params. + * specify KM_TAG_ADDITIONAL_DATA, but only if no input data was provided to update(). * * \param[in] signature The signature to be verified if the purpose specified in the begin() * call was KM_PURPOSE_VERIFY. * - * \param[in] signature_length The length of \p signature. - * * \param[out] output The output data, if any. The caller assumes ownership of the allocated * buffer. * - * \param[out] output_length The length of the output buffer. - * * If the operation being finished is a signature verification or an AEAD-mode decryption and * verification fails then finish() will return KM_ERROR_VERIFICATION_FAILED. */ @@ -556,7 +526,7 @@ struct keymaster1_device { /** * Aborts a cryptographic operation begun with begin(), freeing all internal resources and - * invalidating operation_handle. + * invalidating \p operation_handle. */ keymaster_error_t (*abort)(const struct keymaster1_device* dev, keymaster_operation_handle_t operation_handle); diff --git a/include/hardware/keymaster_defs.h b/include/hardware/keymaster_defs.h index b19086e..5be956d 100644 --- a/include/hardware/keymaster_defs.h +++ b/include/hardware/keymaster_defs.h @@ -115,8 +115,7 @@ typedef enum { KM_TAG_CREATION_DATETIME = KM_DATE | 701, /* Key creation time */ KM_TAG_ORIGIN = KM_ENUM | 702, /* keymaster_key_origin_t. */ KM_TAG_ROLLBACK_RESISTANT = KM_BOOL | 703, /* Whether key is rollback-resistant. */ - KM_TAG_ROOT_OF_TRUST = KM_BYTES | 704, /* Root of trust ID. Empty array means usable by all - roots. */ + KM_TAG_ROOT_OF_TRUST = KM_BYTES | 704, /* Root of trust ID. */ /* Tags used only to provide data to or receive data from operations */ KM_TAG_ASSOCIATED_DATA = KM_BYTES | 1000, /* Used to provide associated data for AEAD modes. */ -- cgit v1.1