mbedtls/include/psa/crypto_extra.h
Gilles Peskine 7cfcb3fc03 Change the encoding of key types to have a parity bit
Change the encoding of key types, EC curve families and DH group
families to make the low-order bit a parity bit (with even parity).

This ensures that distinct key type values always have a Hamming
distance of at least 2, which makes it easier for implementations to
resist single bit flips.
2020-01-31 10:24:21 +01:00

610 lines
24 KiB
C

/**
* \file psa/crypto_extra.h
*
* \brief PSA cryptography module: Mbed TLS vendor extensions
*
* \note This file may not be included directly. Applications must
* include psa/crypto.h.
*
* This file is reserved for vendor-specific definitions.
*/
/*
* Copyright (C) 2018, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* 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.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#ifndef PSA_CRYPTO_EXTRA_H
#define PSA_CRYPTO_EXTRA_H
#include "mbedtls/platform_util.h"
#include "crypto_compat.h"
#ifdef __cplusplus
extern "C" {
#endif
/* UID for secure storage seed */
#define PSA_CRYPTO_ITS_RANDOM_SEED_UID 0xFFFFFF52
/** \addtogroup attributes
* @{
*/
/** \brief Declare the enrollment algorithm for a key.
*
* An operation on a key may indifferently use the algorithm set with
* psa_set_key_algorithm() or with this function.
*
* \param[out] attributes The attribute structure to write to.
* \param alg2 A second algorithm that the key may be used
* for, in addition to the algorithm set with
* psa_set_key_algorithm().
*
* \warning Setting an enrollment algorithm is not recommended, because
* using the same key with different algorithms can allow some
* attacks based on arithmetic relations between different
* computations made with the same key, or can escalate harmless
* side channels into exploitable ones. Use this function only
* if it is necessary to support a protocol for which it has been
* verified that the usage of the key with multiple algorithms
* is safe.
*/
static inline void psa_set_key_enrollment_algorithm(
psa_key_attributes_t *attributes,
psa_algorithm_t alg2)
{
attributes->core.policy.alg2 = alg2;
}
/** Retrieve the enrollment algorithm policy from key attributes.
*
* \param[in] attributes The key attribute structure to query.
*
* \return The enrollment algorithm stored in the attribute structure.
*/
static inline psa_algorithm_t psa_get_key_enrollment_algorithm(
const psa_key_attributes_t *attributes)
{
return( attributes->core.policy.alg2 );
}
#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
/** Retrieve the slot number where a key is stored.
*
* A slot number is only defined for keys that are stored in a secure
* element.
*
* This information is only useful if the secure element is not entirely
* managed through the PSA Cryptography API. It is up to the secure
* element driver to decide how PSA slot numbers map to any other interface
* that the secure element may have.
*
* \param[in] attributes The key attribute structure to query.
* \param[out] slot_number On success, the slot number containing the key.
*
* \retval #PSA_SUCCESS
* The key is located in a secure element, and \p *slot_number
* indicates the slot number that contains it.
* \retval #PSA_ERROR_NOT_PERMITTED
* The caller is not permitted to query the slot number.
* Mbed Crypto currently does not return this error.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* The key is not located in a secure element.
*/
psa_status_t psa_get_key_slot_number(
const psa_key_attributes_t *attributes,
psa_key_slot_number_t *slot_number );
/** Choose the slot number where a key is stored.
*
* This function declares a slot number in the specified attribute
* structure.
*
* A slot number is only meaningful for keys that are stored in a secure
* element. It is up to the secure element driver to decide how PSA slot
* numbers map to any other interface that the secure element may have.
*
* \note Setting a slot number in key attributes for a key creation can
* cause the following errors when creating the key:
* - #PSA_ERROR_NOT_SUPPORTED if the selected secure element does
* not support choosing a specific slot number.
* - #PSA_ERROR_NOT_PERMITTED if the caller is not permitted to
* choose slot numbers in general or to choose this specific slot.
* - #PSA_ERROR_INVALID_ARGUMENT if the chosen slot number is not
* valid in general or not valid for this specific key.
* - #PSA_ERROR_ALREADY_EXISTS if there is already a key in the
* selected slot.
*
* \param[out] attributes The attribute structure to write to.
* \param slot_number The slot number to set.
*/
static inline void psa_set_key_slot_number(
psa_key_attributes_t *attributes,
psa_key_slot_number_t slot_number )
{
attributes->core.flags |= MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER;
attributes->slot_number = slot_number;
}
/** Remove the slot number attribute from a key attribute structure.
*
* This function undoes the action of psa_set_key_slot_number().
*
* \param[out] attributes The attribute structure to write to.
*/
static inline void psa_clear_key_slot_number(
psa_key_attributes_t *attributes )
{
attributes->core.flags &= ~MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER;
}
/** Register a key that is already present in a secure element.
*
* The key must be located in a secure element designated by the
* lifetime field in \p attributes, in the slot set with
* psa_set_key_slot_number() in the attribute structure.
* This function makes the key available through the key identifier
* specified in \p attributes.
*
* \param[in] attributes The attributes of the existing key.
*
* \retval #PSA_SUCCESS
* The key was successfully registered.
* Note that depending on the design of the driver, this may or may
* not guarantee that a key actually exists in the designated slot
* and is compatible with the specified attributes.
* \retval #PSA_ERROR_ALREADY_EXISTS
* There is already a key with the identifier specified in
* \p attributes.
* \retval #PSA_ERROR_NOT_SUPPORTED
* The secure element driver for the specified lifetime does not
* support registering a key.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \p attributes specifies a lifetime which is not located
* in a secure element.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* No slot number is specified in \p attributes,
* or the specified slot number is not valid.
* \retval #PSA_ERROR_NOT_PERMITTED
* The caller is not authorized to register the specified key slot.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
* \retval #PSA_ERROR_COMMUNICATION_FAILURE
* \retval #PSA_ERROR_HARDWARE_FAILURE
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* \retval #PSA_ERROR_BAD_STATE
* The library has not been previously initialized by psa_crypto_init().
* It is implementation-dependent whether a failure to initialize
* results in this error code.
*/
psa_status_t mbedtls_psa_register_se_key(
const psa_key_attributes_t *attributes);
#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
/**@}*/
/**
* \brief Library deinitialization.
*
* This function clears all data associated with the PSA layer,
* including the whole key store.
*
* This is an Mbed TLS extension.
*/
void mbedtls_psa_crypto_free( void );
/** \brief Statistics about
* resource consumption related to the PSA keystore.
*
* \note The content of this structure is not part of the stable API and ABI
* of Mbed Crypto and may change arbitrarily from version to version.
*/
typedef struct mbedtls_psa_stats_s
{
/** Number of slots containing key material for a volatile key. */
size_t volatile_slots;
/** Number of slots containing key material for a key which is in
* internal persistent storage. */
size_t persistent_slots;
/** Number of slots containing a reference to a key in a
* secure element. */
size_t external_slots;
/** Number of slots which are occupied, but do not contain
* key material yet. */
size_t half_filled_slots;
/** Number of slots that contain cache data. */
size_t cache_slots;
/** Number of slots that are not used for anything. */
size_t empty_slots;
/** Largest key id value among open keys in internal persistent storage. */
psa_app_key_id_t max_open_internal_key_id;
/** Largest key id value among open keys in secure elements. */
psa_app_key_id_t max_open_external_key_id;
} mbedtls_psa_stats_t;
/** \brief Get statistics about
* resource consumption related to the PSA keystore.
*
* \note When Mbed Crypto is built as part of a service, with isolation
* between the application and the keystore, the service may or
* may not expose this function.
*/
void mbedtls_psa_get_stats( mbedtls_psa_stats_t *stats );
/**
* \brief Inject an initial entropy seed for the random generator into
* secure storage.
*
* This function injects data to be used as a seed for the random generator
* used by the PSA Crypto implementation. On devices that lack a trusted
* entropy source (preferably a hardware random number generator),
* the Mbed PSA Crypto implementation uses this value to seed its
* random generator.
*
* On devices without a trusted entropy source, this function must be
* called exactly once in the lifetime of the device. On devices with
* a trusted entropy source, calling this function is optional.
* In all cases, this function may only be called before calling any
* other function in the PSA Crypto API, including psa_crypto_init().
*
* When this function returns successfully, it populates a file in
* persistent storage. Once the file has been created, this function
* can no longer succeed.
*
* If any error occurs, this function does not change the system state.
* You can call this function again after correcting the reason for the
* error if possible.
*
* \warning This function **can** fail! Callers MUST check the return status.
*
* \warning If you use this function, you should use it as part of a
* factory provisioning process. The value of the injected seed
* is critical to the security of the device. It must be
* *secret*, *unpredictable* and (statistically) *unique per device*.
* You should be generate it randomly using a cryptographically
* secure random generator seeded from trusted entropy sources.
* You should transmit it securely to the device and ensure
* that its value is not leaked or stored anywhere beyond the
* needs of transmitting it from the point of generation to
* the call of this function, and erase all copies of the value
* once this function returns.
*
* This is an Mbed TLS extension.
*
* \note This function is only available on the following platforms:
* * If the compile-time option MBEDTLS_PSA_INJECT_ENTROPY is enabled.
* Note that you must provide compatible implementations of
* mbedtls_nv_seed_read and mbedtls_nv_seed_write.
* * In a client-server integration of PSA Cryptography, on the client side,
* if the server supports this feature.
* \param[in] seed Buffer containing the seed value to inject.
* \param[in] seed_size Size of the \p seed buffer.
* The size of the seed in bytes must be greater
* or equal to both #MBEDTLS_ENTROPY_MIN_PLATFORM
* and #MBEDTLS_ENTROPY_BLOCK_SIZE.
* It must be less or equal to
* #MBEDTLS_ENTROPY_MAX_SEED_SIZE.
*
* \retval #PSA_SUCCESS
* The seed value was injected successfully. The random generator
* of the PSA Crypto implementation is now ready for use.
* You may now call psa_crypto_init() and use the PSA Crypto
* implementation.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \p seed_size is out of range.
* \retval #PSA_ERROR_STORAGE_FAILURE
* There was a failure reading or writing from storage.
* \retval #PSA_ERROR_NOT_PERMITTED
* The library has already been initialized. It is no longer
* possible to call this function.
*/
psa_status_t mbedtls_psa_inject_entropy(const uint8_t *seed,
size_t seed_size);
/** \addtogroup crypto_types
* @{
*/
/** DSA public key.
*
* The import and export format is the
* representation of the public key `y = g^x mod p` as a big-endian byte
* string. The length of the byte string is the length of the base prime `p`
* in bytes.
*/
#define PSA_KEY_TYPE_DSA_PUBLIC_KEY ((psa_key_type_t)0x4002)
/** DSA key pair (private and public key).
*
* The import and export format is the
* representation of the private key `x` as a big-endian byte string. The
* length of the byte string is the private key size in bytes (leading zeroes
* are not stripped).
*
* Determinstic DSA key derivation with psa_generate_derived_key follows
* FIPS 186-4 §B.1.2: interpret the byte string as integer
* in big-endian order. Discard it if it is not in the range
* [0, *N* - 2] where *N* is the boundary of the private key domain
* (the prime *p* for Diffie-Hellman, the subprime *q* for DSA,
* or the order of the curve's base point for ECC).
* Add 1 to the resulting integer and use this as the private key *x*.
*
*/
#define PSA_KEY_TYPE_DSA_KEY_PAIR ((psa_key_type_t)0x7002)
/** Whether a key type is an DSA key (pair or public-only). */
#define PSA_KEY_TYPE_IS_DSA(type) \
(PSA_KEY_TYPE_PUBLIC_KEY_OF_KEY_PAIR(type) == PSA_KEY_TYPE_DSA_PUBLIC_KEY)
#define PSA_ALG_DSA_BASE ((psa_algorithm_t)0x10040000)
/** DSA signature with hashing.
*
* This is the signature scheme defined by FIPS 186-4,
* with a random per-message secret number (*k*).
*
* \param hash_alg A hash algorithm (\c PSA_ALG_XXX value such that
* #PSA_ALG_IS_HASH(\p hash_alg) is true).
* This includes #PSA_ALG_ANY_HASH
* when specifying the algorithm in a usage policy.
*
* \return The corresponding DSA signature algorithm.
* \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_DSA(hash_alg) \
(PSA_ALG_DSA_BASE | ((hash_alg) & PSA_ALG_HASH_MASK))
#define PSA_ALG_DETERMINISTIC_DSA_BASE ((psa_algorithm_t)0x10050000)
#define PSA_ALG_DSA_DETERMINISTIC_FLAG PSA_ALG_ECDSA_DETERMINISTIC_FLAG
/** Deterministic DSA signature with hashing.
*
* This is the deterministic variant defined by RFC 6979 of
* the signature scheme defined by FIPS 186-4.
*
* \param hash_alg A hash algorithm (\c PSA_ALG_XXX value such that
* #PSA_ALG_IS_HASH(\p hash_alg) is true).
* This includes #PSA_ALG_ANY_HASH
* when specifying the algorithm in a usage policy.
*
* \return The corresponding DSA signature algorithm.
* \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_DETERMINISTIC_DSA(hash_alg) \
(PSA_ALG_DETERMINISTIC_DSA_BASE | ((hash_alg) & PSA_ALG_HASH_MASK))
#define PSA_ALG_IS_DSA(alg) \
(((alg) & ~PSA_ALG_HASH_MASK & ~PSA_ALG_DSA_DETERMINISTIC_FLAG) == \
PSA_ALG_DSA_BASE)
#define PSA_ALG_DSA_IS_DETERMINISTIC(alg) \
(((alg) & PSA_ALG_DSA_DETERMINISTIC_FLAG) != 0)
#define PSA_ALG_IS_DETERMINISTIC_DSA(alg) \
(PSA_ALG_IS_DSA(alg) && PSA_ALG_DSA_IS_DETERMINISTIC(alg))
#define PSA_ALG_IS_RANDOMIZED_DSA(alg) \
(PSA_ALG_IS_DSA(alg) && !PSA_ALG_DSA_IS_DETERMINISTIC(alg))
/* We need to expand the sample definition of this macro from
* the API definition. */
#undef PSA_ALG_IS_HASH_AND_SIGN
#define PSA_ALG_IS_HASH_AND_SIGN(alg) \
(PSA_ALG_IS_RSA_PSS(alg) || PSA_ALG_IS_RSA_PKCS1V15_SIGN(alg) || \
PSA_ALG_IS_DSA(alg) || PSA_ALG_IS_ECDSA(alg))
/**@}*/
/** \addtogroup attributes
* @{
*/
/** Custom Diffie-Hellman group.
*
* For keys of type #PSA_KEY_TYPE_DH_PUBLIC_KEY(#PSA_DH_GROUP_CUSTOM) or
* #PSA_KEY_TYPE_DH_KEY_PAIR(#PSA_DH_GROUP_CUSTOM), the group data comes
* from domain parameters set by psa_set_key_domain_parameters().
*/
#define PSA_DH_GROUP_CUSTOM ((psa_dh_group_t) 0x7e)
/**
* \brief Set domain parameters for a key.
*
* Some key types require additional domain parameters in addition to
* the key type identifier and the key size. Use this function instead
* of psa_set_key_type() when you need to specify domain parameters.
*
* The format for the required domain parameters varies based on the key type.
*
* - For RSA keys (#PSA_KEY_TYPE_RSA_PUBLIC_KEY or #PSA_KEY_TYPE_RSA_KEY_PAIR),
* the domain parameter data consists of the public exponent,
* represented as a big-endian integer with no leading zeros.
* This information is used when generating an RSA key pair.
* When importing a key, the public exponent is read from the imported
* key data and the exponent recorded in the attribute structure is ignored.
* As an exception, the public exponent 65537 is represented by an empty
* byte string.
* - For DSA keys (#PSA_KEY_TYPE_DSA_PUBLIC_KEY or #PSA_KEY_TYPE_DSA_KEY_PAIR),
* the `Dss-Parms` format as defined by RFC 3279 §2.3.2.
* ```
* Dss-Parms ::= SEQUENCE {
* p INTEGER,
* q INTEGER,
* g INTEGER
* }
* ```
* - For Diffie-Hellman key exchange keys
* (#PSA_KEY_TYPE_DH_PUBLIC_KEY(#PSA_DH_GROUP_CUSTOM) or
* #PSA_KEY_TYPE_DH_KEY_PAIR(#PSA_DH_GROUP_CUSTOM)), the
* `DomainParameters` format as defined by RFC 3279 §2.3.3.
* ```
* DomainParameters ::= SEQUENCE {
* p INTEGER, -- odd prime, p=jq +1
* g INTEGER, -- generator, g
* q INTEGER, -- factor of p-1
* j INTEGER OPTIONAL, -- subgroup factor
* validationParms ValidationParms OPTIONAL
* }
* ValidationParms ::= SEQUENCE {
* seed BIT STRING,
* pgenCounter INTEGER
* }
* ```
*
* \note This function may allocate memory or other resources.
* Once you have called this function on an attribute structure,
* you must call psa_reset_key_attributes() to free these resources.
*
* \note This is an experimental extension to the interface. It may change
* in future versions of the library.
*
* \param[in,out] attributes Attribute structure where the specified domain
* parameters will be stored.
* If this function fails, the content of
* \p attributes is not modified.
* \param type Key type (a \c PSA_KEY_TYPE_XXX value).
* \param[in] data Buffer containing the key domain parameters.
* The content of this buffer is interpreted
* according to \p type as described above.
* \param data_length Size of the \p data buffer in bytes.
*
* \retval #PSA_SUCCESS
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \retval #PSA_ERROR_NOT_SUPPORTED
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
*/
psa_status_t psa_set_key_domain_parameters(psa_key_attributes_t *attributes,
psa_key_type_t type,
const uint8_t *data,
size_t data_length);
/**
* \brief Get domain parameters for a key.
*
* Get the domain parameters for a key with this function, if any. The format
* of the domain parameters written to \p data is specified in the
* documentation for psa_set_key_domain_parameters().
*
* \note This is an experimental extension to the interface. It may change
* in future versions of the library.
*
* \param[in] attributes The key attribute structure to query.
* \param[out] data On success, the key domain parameters.
* \param data_size Size of the \p data buffer in bytes.
* The buffer is guaranteed to be large
* enough if its size in bytes is at least
* the value given by
* PSA_KEY_DOMAIN_PARAMETERS_SIZE().
* \param[out] data_length On success, the number of bytes
* that make up the key domain parameters data.
*
* \retval #PSA_SUCCESS
* \retval #PSA_ERROR_BUFFER_TOO_SMALL
*/
psa_status_t psa_get_key_domain_parameters(
const psa_key_attributes_t *attributes,
uint8_t *data,
size_t data_size,
size_t *data_length);
/** Safe output buffer size for psa_get_key_domain_parameters().
*
* This macro returns a compile-time constant if its arguments are
* compile-time constants.
*
* \warning This function may call its arguments multiple times or
* zero times, so you should not pass arguments that contain
* side effects.
*
* \note This is an experimental extension to the interface. It may change
* in future versions of the library.
*
* \param key_type A supported key type.
* \param key_bits The size of the key in bits.
*
* \return If the parameters are valid and supported, return
* a buffer size in bytes that guarantees that
* psa_get_key_domain_parameters() will not fail with
* #PSA_ERROR_BUFFER_TOO_SMALL.
* If the parameters are a valid combination that is not supported
* by the implementation, this macro shall return either a
* sensible size or 0.
* If the parameters are not valid, the
* return value is unspecified.
*/
#define PSA_KEY_DOMAIN_PARAMETERS_SIZE(key_type, key_bits) \
(PSA_KEY_TYPE_IS_RSA(key_type) ? sizeof(int) : \
PSA_KEY_TYPE_IS_DH(key_type) ? PSA_DH_KEY_DOMAIN_PARAMETERS_SIZE(key_bits) : \
PSA_KEY_TYPE_IS_DSA(key_type) ? PSA_DSA_KEY_DOMAIN_PARAMETERS_SIZE(key_bits) : \
0)
#define PSA_DH_KEY_DOMAIN_PARAMETERS_SIZE(key_bits) \
(4 + (PSA_BITS_TO_BYTES(key_bits) + 5) * 3 /*without optional parts*/)
#define PSA_DSA_KEY_DOMAIN_PARAMETERS_SIZE(key_bits) \
(4 + (PSA_BITS_TO_BYTES(key_bits) + 5) * 2 /*p, g*/ + 34 /*q*/)
/**@}*/
/** \defgroup psa_tls_helpers TLS helper functions
* @{
*/
#if defined(MBEDTLS_ECP_C)
#include <mbedtls/ecp.h>
/** Convert an ECC curve identifier from the Mbed TLS encoding to PSA.
*
* \note This function is provided solely for the convenience of
* Mbed TLS and may be removed at any time without notice.
*
* \param grpid An Mbed TLS elliptic curve identifier
* (`MBEDTLS_ECP_DP_xxx`).
* \param[out] bits On success, the bit size of the curve.
*
* \return The corresponding PSA elliptic curve identifier
* (`PSA_ECC_CURVE_xxx`).
* \return \c 0 on failure (\p grpid is not recognized).
*/
psa_ecc_curve_t mbedtls_ecc_group_to_psa( mbedtls_ecp_group_id grpid,
size_t *bits );
/** Convert an ECC curve identifier from the PSA encoding to Mbed TLS.
*
* \note This function is provided solely for the convenience of
* Mbed TLS and may be removed at any time without notice.
*
* \param curve A PSA elliptic curve identifier
* (`PSA_ECC_CURVE_xxx`).
* \param byte_length The byte-length of a private key on \p curve.
*
* \return The corresponding Mbed TLS elliptic curve identifier
* (`MBEDTLS_ECP_DP_xxx`).
* \return #MBEDTLS_ECP_DP_NONE if \c curve is not recognized.
* \return #MBEDTLS_ECP_DP_NONE if \p byte_length is not
* correct for \p curve.
*/
mbedtls_ecp_group_id mbedtls_ecc_group_of_psa( psa_ecc_curve_t curve,
size_t byte_length );
#endif /* MBEDTLS_ECP_C */
/**@}*/
#ifdef __cplusplus
}
#endif
#endif /* PSA_CRYPTO_EXTRA_H */