New API function: psa_key_agreement

Set up a generator from a key agreement.
This commit is contained in:
Gilles Peskine 2018-09-18 12:01:02 +02:00
parent 8feb3a886d
commit 01d718cee8
4 changed files with 256 additions and 0 deletions

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@ -3191,6 +3191,46 @@ psa_status_t psa_key_derivation(psa_crypto_generator_t *generator,
size_t label_length,
size_t capacity);
/** Set up a key agreement operation.
*
* A key agreement algorithm takes two inputs: a private key \p private_key
* a public key \p peer_key.
* The result of this function is a byte generator which can
* be used to produce keys and other cryptographic material.
*
* \param[in,out] generator The generator object to set up. It must
* have been initialized to all-bits-zero,
* a logical zero (`{0}`),
* \c PSA_CRYPTO_GENERATOR_INIT or
* psa_crypto_generator_init().
* \param private_key Slot containing the private key to use.
* \param[in] peer_key Public key of the peer.
* \param peer_key_length Size of \p peer_key in bytes.
* \param alg The key agreement algorithm to compute
* (\c PSA_ALG_XXX value such that
* #PSA_ALG_IS_KEY_AGREEMENT(\p alg) is true).
*
* \retval #PSA_SUCCESS
* Success.
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \c private_key is not compatible with \c alg,
* or \p peer_key is not valid for \c alg or not compatible with
* \c private_key.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \c alg is not supported or is not a key derivation algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
* \retval #PSA_ERROR_COMMUNICATION_FAILURE
* \retval #PSA_ERROR_HARDWARE_FAILURE
* \retval #PSA_ERROR_TAMPERING_DETECTED
*/
psa_status_t psa_key_agreement(psa_crypto_generator_t *generator,
psa_key_slot_t private_key,
const uint8_t *peer_key,
size_t peer_key_length,
psa_algorithm_t alg);
/**@}*/
/** \defgroup random Random generation

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@ -3589,6 +3589,66 @@ psa_status_t psa_key_derivation( psa_crypto_generator_t *generator,
/****************************************************************/
/* Key agreement */
/****************************************************************/
#define PSA_KEY_AGREEMENT_MAX_SHARED_SECRET_SIZE MBEDTLS_ECP_MAX_BYTES
static psa_status_t psa_key_agreement_internal( psa_crypto_generator_t *generator,
key_slot_t *private_key,
const uint8_t *peer_key,
size_t peer_key_length,
psa_algorithm_t alg )
{
psa_status_t status;
uint8_t shared_secret[PSA_KEY_AGREEMENT_MAX_SHARED_SECRET_SIZE];
size_t shared_secret_length = 0;
/* Step 1: run the secret agreement algorithm to generate the shared
* secret. */
switch( PSA_ALG_KEY_AGREEMENT_GET_BASE( alg ) )
{
default:
return( PSA_ERROR_NOT_SUPPORTED );
}
if( status != PSA_SUCCESS )
goto exit;
/* Step 2: set up the key derivation to generate key material from
* the shared secret. */
status = psa_key_derivation_internal( generator,
shared_secret, shared_secret_length,
PSA_ALG_KEY_AGREEMENT_GET_KDF( alg ),
NULL, 0, NULL, 0,
PSA_GENERATOR_UNBRIDLED_CAPACITY );
exit:
mbedtls_zeroize( shared_secret, shared_secret_length );
return( status );
}
psa_status_t psa_key_agreement( psa_crypto_generator_t *generator,
psa_key_slot_t private_key,
const uint8_t *peer_key,
size_t peer_key_length,
psa_algorithm_t alg )
{
key_slot_t *slot;
psa_status_t status;
if( ! PSA_ALG_IS_KEY_AGREEMENT( alg ) )
return( PSA_ERROR_INVALID_ARGUMENT );
status = psa_get_key_from_slot( private_key, &slot,
PSA_KEY_USAGE_DERIVE, alg );
if( status != PSA_SUCCESS )
return( status );
return( psa_key_agreement_internal( generator,
slot,
peer_key, peer_key_length,
alg ) );
}
/****************************************************************/
/* Random generation */
/****************************************************************/

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@ -435,6 +435,18 @@ PSA key policy: derive, wrong algorithm
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA256_C
derive_key_policy:PSA_KEY_USAGE_DERIVE:PSA_ALG_HKDF(PSA_ALG_SHA_256):PSA_KEY_TYPE_DERIVE:"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa":PSA_ALG_HKDF(PSA_ALG_SHA_224)
PSA key policy: agreement, permitted
depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECDH_C
agreement_key_policy:PSA_KEY_USAGE_DERIVE:PSA_ALG_ECDH(PSA_ALG_SELECT_RAW):PSA_KEY_TYPE_ECC_KEYPAIR(PSA_ECC_CURVE_SECP256R1):"3077020101042049c9a8c18c4b885638c431cf1df1c994131609b580d4fd43a0cab17db2f13eeea00a06082a8648ce3d030107a144034200047772656f814b399279d5e1f1781fac6f099a3c5ca1b0e35351834b08b65e0b572590cdaf8f769361bcf34acfc11e5e074e8426bdde04be6e653945449617de45":PSA_ALG_ECDH(PSA_ALG_SELECT_RAW)
PSA key policy: agreement, not permitted
depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECDH_C
agreement_key_policy:0:PSA_ALG_ECDH(PSA_ALG_SELECT_RAW):PSA_KEY_TYPE_ECC_KEYPAIR(PSA_ECC_CURVE_SECP256R1):"3077020101042049c9a8c18c4b885638c431cf1df1c994131609b580d4fd43a0cab17db2f13eeea00a06082a8648ce3d030107a144034200047772656f814b399279d5e1f1781fac6f099a3c5ca1b0e35351834b08b65e0b572590cdaf8f769361bcf34acfc11e5e074e8426bdde04be6e653945449617de45":PSA_ALG_ECDH(PSA_ALG_SELECT_RAW)
PSA key policy: agreement, wrong algorithm
depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECDH_C
agreement_key_policy:PSA_KEY_USAGE_DERIVE:PSA_ALG_ECDH(PSA_ALG_SELECT_RAW):PSA_KEY_TYPE_ECC_KEYPAIR(PSA_ECC_CURVE_SECP256R1):"3077020101042049c9a8c18c4b885638c431cf1df1c994131609b580d4fd43a0cab17db2f13eeea00a06082a8648ce3d030107a144034200047772656f814b399279d5e1f1781fac6f099a3c5ca1b0e35351834b08b65e0b572590cdaf8f769361bcf34acfc11e5e074e8426bdde04be6e653945449617de45":PSA_ALG_FFDH(PSA_ALG_SELECT_RAW)
PSA key lifetime: set and get volatile
key_lifetime:PSA_KEY_LIFETIME_VOLATILE
@ -1525,6 +1537,14 @@ PSA key derivation: HKDF SHA-256, derive key, 1+41
depends_on:MBEDTLS_MD_C:MBEDTLS_SHA256_C
derive_key_export:PSA_ALG_HKDF(PSA_ALG_SHA_256):"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b":"000102030405060708090a0b0c":"f0f1f2f3f4f5f6f7f8f9":1:41
PSA key agreement setup: ECDH, unknown KDF
depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECDH_C
key_agreement_setup:PSA_ALG_ECDH(0):PSA_KEY_TYPE_ECC_KEYPAIR(PSA_ECC_CURVE_SECP256R1):"3078020101042100c88f01f510d9ac3f70a292daa2316de544e9aab8afe84049c62a9c57862d1433a00a06082a8648ce3d030107a14403420004dad0b65394221cf9b051e1feca5787d098dfe637fc90b9ef945d0c37725811805271a0461cdb8252d61f1c456fa3e59ab1f45b33accf5f58389e0577b8990bb3":"3059301306072a8648ce3d020106082a8648ce3d03010703420004d12dfb5289c8d4f81208b70270398c342296970a0bccb74c736fc7554494bf6356fbf3ca366cc23e8157854c13c58d6aac23f046ada30f8353e74f33039872ab":PSA_ERROR_NOT_SUPPORTED
PSA key agreement setup: not a key agreement algorithm
depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECDH_C
key_agreement_setup:PSA_ALG_HKDF( PSA_ALG_SHA_256 ):PSA_KEY_TYPE_ECC_KEYPAIR(PSA_ECC_CURVE_SECP256R1):"3078020101042100c88f01f510d9ac3f70a292daa2316de544e9aab8afe84049c62a9c57862d1433a00a06082a8648ce3d030107a14403420004dad0b65394221cf9b051e1feca5787d098dfe637fc90b9ef945d0c37725811805271a0461cdb8252d61f1c456fa3e59ab1f45b33accf5f58389e0577b8990bb3":"3059301306072a8648ce3d020106082a8648ce3d03010703420004d12dfb5289c8d4f81208b70270398c342296970a0bccb74c736fc7554494bf6356fbf3ca366cc23e8157854c13c58d6aac23f046ada30f8353e74f33039872ab":PSA_ERROR_INVALID_ARGUMENT
PSA generate random: 0 bytes
generate_random:0

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@ -392,6 +392,51 @@ exit:
return( 0 );
}
static int exercise_key_agreement_key( psa_key_slot_t key,
psa_key_usage_t usage,
psa_algorithm_t alg )
{
psa_crypto_generator_t generator = PSA_CRYPTO_GENERATOR_INIT;
psa_key_type_t key_type;
psa_key_type_t public_key_type;
size_t key_bits;
uint8_t *public_key = NULL;
size_t public_key_length;
unsigned char output[1];
int ok = 0;
if( usage & PSA_KEY_USAGE_DERIVE )
{
/* We need two keys to exercise key agreement. Exercise the
* private key against its own public key. */
TEST_ASSERT( psa_get_key_information( key,
&key_type,
&key_bits ) == PSA_SUCCESS );
public_key_type = PSA_KEY_TYPE_PUBLIC_KEY_OF_KEYPAIR( key_type );
public_key_length = PSA_KEY_EXPORT_MAX_SIZE( public_key_type,
key_bits );
public_key = mbedtls_calloc( 1, public_key_length );
TEST_ASSERT( public_key != NULL );
TEST_ASSERT(
psa_export_public_key( key,
public_key, public_key_length,
&public_key_length ) == PSA_SUCCESS );
TEST_ASSERT( psa_key_agreement( &generator,
key,
public_key, public_key_length,
alg ) == PSA_SUCCESS );
TEST_ASSERT( psa_generator_read( &generator,
output,
sizeof( output ) ) == PSA_SUCCESS );
TEST_ASSERT( psa_generator_abort( &generator ) == PSA_SUCCESS );
}
ok = 1;
exit:
mbedtls_free( public_key );
return( ok );
}
static int is_oid_of_key_type( psa_key_type_t type,
const uint8_t *oid, size_t oid_length )
{
@ -737,6 +782,8 @@ static int exercise_key( psa_key_slot_t slot,
ok = exercise_asymmetric_encryption_key( slot, usage, alg );
else if( PSA_ALG_IS_KEY_DERIVATION( alg ) )
ok = exercise_key_derivation_key( slot, usage, alg );
else if( PSA_ALG_IS_KEY_AGREEMENT( alg ) )
ok = exercise_key_agreement_key( slot, usage, alg );
else
{
char message[40];
@ -1271,6 +1318,7 @@ void import_and_exercise_key( data_t *data,
PSA_KEY_USAGE_ENCRYPT :
PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT ) :
PSA_ALG_IS_KEY_DERIVATION( alg ) ? PSA_KEY_USAGE_DERIVE :
PSA_ALG_IS_KEY_AGREEMENT( alg ) ? PSA_KEY_USAGE_DERIVE :
0 );
psa_key_policy_t policy;
psa_key_type_t got_type;
@ -1642,6 +1690,61 @@ exit:
}
/* END_CASE */
/* BEGIN_CASE */
void agreement_key_policy( int policy_usage,
int policy_alg,
int key_type_arg,
data_t *key_data,
int exercise_alg )
{
int key_slot = 1;
psa_key_policy_t policy;
psa_key_type_t key_type = key_type_arg;
psa_key_type_t public_key_type;
size_t key_bits;
uint8_t *public_key = NULL;
size_t public_key_length;
psa_crypto_generator_t generator = PSA_CRYPTO_GENERATOR_INIT;
psa_status_t status;
TEST_ASSERT( psa_crypto_init( ) == PSA_SUCCESS );
psa_key_policy_init( &policy );
psa_key_policy_set_usage( &policy, policy_usage, policy_alg );
TEST_ASSERT( psa_set_key_policy( key_slot, &policy ) == PSA_SUCCESS );
TEST_ASSERT( psa_import_key( key_slot, key_type,
key_data->x, key_data->len ) == PSA_SUCCESS );
/* We need two keys to exercise key agreement. Exercise the
* private key against its own public key. */
TEST_ASSERT( psa_get_key_information( key_slot,
&key_type,
&key_bits ) == PSA_SUCCESS );
public_key_type = PSA_KEY_TYPE_PUBLIC_KEY_OF_KEYPAIR( key_type );
public_key_length = PSA_KEY_EXPORT_MAX_SIZE( public_key_type, key_bits );
public_key = mbedtls_calloc( 1, public_key_length );
TEST_ASSERT( public_key != NULL );
TEST_ASSERT( psa_export_public_key( key_slot,
public_key, public_key_length,
&public_key_length ) == PSA_SUCCESS );
status = psa_key_agreement( &generator, key_slot,
public_key, public_key_length,
exercise_alg );
if( policy_alg == exercise_alg &&
( policy_usage & PSA_KEY_USAGE_DERIVE ) != 0 )
TEST_ASSERT( status == PSA_SUCCESS );
else
TEST_ASSERT( status == PSA_ERROR_NOT_PERMITTED );
exit:
psa_generator_abort( &generator );
psa_destroy_key( key_slot );
mbedtls_psa_crypto_free( );
}
/* END_CASE */
/* BEGIN_CASE */
void key_lifetime( int lifetime_arg )
{
@ -3655,6 +3758,39 @@ exit:
}
/* END_CASE */
/* BEGIN_CASE */
void key_agreement_setup( int alg_arg,
int our_key_type_arg, data_t *our_key_data,
data_t *peer_key_data,
int expected_status_arg )
{
psa_key_slot_t our_key = 1;
psa_algorithm_t alg = alg_arg;
psa_key_type_t our_key_type = our_key_type_arg;
psa_crypto_generator_t generator = PSA_CRYPTO_GENERATOR_INIT;
psa_key_policy_t policy;
TEST_ASSERT( psa_crypto_init( ) == PSA_SUCCESS );
psa_key_policy_init( &policy );
psa_key_policy_set_usage( &policy, PSA_KEY_USAGE_DERIVE, alg );
TEST_ASSERT( psa_set_key_policy( our_key, &policy ) == PSA_SUCCESS );
TEST_ASSERT( psa_import_key( our_key, our_key_type,
our_key_data->x,
our_key_data->len ) == PSA_SUCCESS );
TEST_ASSERT( psa_key_agreement( &generator,
our_key,
peer_key_data->x, peer_key_data->len,
alg ) == expected_status_arg );
exit:
psa_generator_abort( &generator );
psa_destroy_key( our_key );
mbedtls_psa_crypto_free( );
}
/* END_CASE */
/* BEGIN_CASE */
void generate_random( int bytes_arg )
{