Set the key size as an attribute
Instead of passing a separate parameter for the key size to
psa_generate_key and psa_generator_import_key, set it through the
attributes, like the key type and other metadata.
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 2046947..2c3288e 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -147,6 +147,7 @@
* by the following functions:
* - psa_make_key_persistent()
* - psa_set_key_type()
+ * - psa_set_key_bits()
* - psa_set_key_usage_flags()
* - psa_set_key_algorithm()
* - psa_reset_key_attributes()
@@ -293,6 +294,20 @@
static void psa_set_key_type(psa_key_attributes_t *attributes,
psa_key_type_t type);
+/** Declare the size of a key.
+ *
+ * This function overwrites any key size previously set in \p attributes.
+ *
+ * This function may be declared as `static` (i.e. without external
+ * linkage). This function may be provided as a function-like macro,
+ * but in this case it must evaluate each of its arguments exactly once.
+ *
+ * \param[out] attributes The attribute structure to write to.
+ * \param bits The key size in bits.
+ */
+static void psa_set_key_bits(psa_key_attributes_t *attributes,
+ size_t bits);
+
/** Retrieve the key type from key attributes.
*
* This function may be declared as `static` (i.e. without external
@@ -331,11 +346,6 @@
* property may not hold in future versions of this specification or
* for implementation-specific values.
*
- * In addition to the attributes that were set when creating the key,
- * this function reports the following data:
- * - The key size in bits, which can be retrieved with
- * psa_get_key_bits().
- *
* \param[in] handle Handle to the key to query.
* \param[in,out] attributes On success, the attributes of the key.
* On failure, equivalent to a
@@ -3018,12 +3028,8 @@
* The generator's capacity is decreased by the number of bytes read.
*
* \param[in] attributes The attributes for the new key.
- * The key size field in \p attributes is
- * ignored; the actual key size is taken
- * from the \p bits parameter instead.
* \param[out] handle On success, a handle to the newly created key.
* \c 0 on failure.
- * \param bits Key size in bits.
* \param[in,out] generator The generator object to read from.
*
* \retval #PSA_SUCCESS
@@ -3054,7 +3060,6 @@
*/
psa_status_t psa_generator_import_key(const psa_key_attributes_t *attributes,
psa_key_handle_t *handle,
- size_t bits,
psa_crypto_generator_t *generator);
/** Abort a generator.
@@ -3383,12 +3388,8 @@
* \brief Generate a key or key pair.
*
* \param[in] attributes The attributes for the new key.
- * The key size field in \p attributes is
- * ignored; the actual key size is taken
- * from the \p bits parameter instead.
* \param[out] handle On success, a handle to the newly created key.
* \c 0 on failure.
- * \param bits Key size in bits.
* \param[in] extra Extra parameters for key generation. The
* interpretation of this parameter depends on
* the key type \c type. All types support \c NULL to
@@ -3447,7 +3448,6 @@
*/
psa_status_t psa_generate_key(const psa_key_attributes_t *attributes,
psa_key_handle_t *handle,
- size_t bits,
const void *extra,
size_t extra_size);
diff --git a/include/psa/crypto_struct.h b/include/psa/crypto_struct.h
index 273f6b6..f89073b 100644
--- a/include/psa/crypto_struct.h
+++ b/include/psa/crypto_struct.h
@@ -333,6 +333,12 @@
return( attributes->type );
}
+static inline void psa_set_key_bits(psa_key_attributes_t *attributes,
+ size_t bits)
+{
+ attributes->bits = bits;
+}
+
static inline size_t psa_get_key_bits(
const psa_key_attributes_t *attributes)
{
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index e035ece..c1e3a3f 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -4222,7 +4222,6 @@
psa_status_t psa_generator_import_key( const psa_key_attributes_t *attributes,
psa_key_handle_t *handle,
- size_t bits,
psa_crypto_generator_t *generator )
{
psa_status_t status;
@@ -4230,7 +4229,9 @@
status = psa_start_key_creation( attributes, handle, &slot );
if( status == PSA_SUCCESS )
{
- status = psa_generator_import_key_internal( slot, bits, generator );
+ status = psa_generator_import_key_internal( slot,
+ attributes->bits,
+ generator );
}
if( status == PSA_SUCCESS )
status = psa_finish_key_creation( slot );
@@ -5139,7 +5140,6 @@
psa_status_t psa_generate_key( const psa_key_attributes_t *attributes,
psa_key_handle_t *handle,
- size_t bits,
const void *extra,
size_t extra_size )
{
@@ -5148,7 +5148,8 @@
status = psa_start_key_creation( attributes, handle, &slot );
if( status == PSA_SUCCESS )
{
- status = psa_generate_key_internal( slot, bits, extra, extra_size );
+ status = psa_generate_key_internal( slot, attributes->bits,
+ extra, extra_size );
}
if( status == PSA_SUCCESS )
status = psa_finish_key_creation( slot );
diff --git a/programs/psa/crypto_examples.c b/programs/psa/crypto_examples.c
index 07d1fd2..72fa12f 100644
--- a/programs/psa/crypto_examples.c
+++ b/programs/psa/crypto_examples.c
@@ -162,9 +162,9 @@
PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT );
psa_set_key_algorithm( &attributes, alg );
psa_set_key_type( &attributes, PSA_KEY_TYPE_AES );
+ psa_set_key_bits( &attributes, key_bits );
- status = psa_generate_key( &attributes, &key_handle, key_bits,
- NULL, 0 );
+ status = psa_generate_key( &attributes, &key_handle, NULL, 0 );
ASSERT_STATUS( status, PSA_SUCCESS );
status = cipher_encrypt( key_handle, alg, iv, sizeof( iv ),
@@ -213,9 +213,9 @@
PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT );
psa_set_key_algorithm( &attributes, alg );
psa_set_key_type( &attributes, PSA_KEY_TYPE_AES );
+ psa_set_key_bits( &attributes, key_bits );
- status = psa_generate_key( &attributes, &key_handle, key_bits,
- NULL, 0 );
+ status = psa_generate_key( &attributes, &key_handle, NULL, 0 );
ASSERT_STATUS( status, PSA_SUCCESS );
status = cipher_encrypt( key_handle, alg, iv, sizeof( iv ),
@@ -260,9 +260,9 @@
PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT );
psa_set_key_algorithm( &attributes, alg );
psa_set_key_type( &attributes, PSA_KEY_TYPE_AES );
+ psa_set_key_bits( &attributes, key_bits );
- status = psa_generate_key( &attributes, &key_handle, key_bits,
- NULL, 0 );
+ status = psa_generate_key( &attributes, &key_handle, NULL, 0 );
ASSERT_STATUS( status, PSA_SUCCESS );
status = cipher_encrypt( key_handle, alg, iv, sizeof( iv ),
diff --git a/programs/psa/key_ladder_demo.c b/programs/psa/key_ladder_demo.c
index b84e7fd..c1e296f 100644
--- a/programs/psa/key_ladder_demo.c
+++ b/programs/psa/key_ladder_demo.c
@@ -206,10 +206,9 @@
PSA_KEY_USAGE_DERIVE | PSA_KEY_USAGE_EXPORT );
psa_set_key_algorithm( &attributes, KDF_ALG );
psa_set_key_type( &attributes, PSA_KEY_TYPE_DERIVE );
+ psa_set_key_bits( &attributes, PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ) );
- PSA_CHECK( psa_generate_key( &attributes, &key_handle,
- PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ),
- NULL, 0 ) );
+ PSA_CHECK( psa_generate_key( &attributes, &key_handle, NULL, 0 ) );
PSA_CHECK( save_key( key_handle, key_file_name ) );
@@ -287,6 +286,7 @@
PSA_KEY_USAGE_DERIVE | PSA_KEY_USAGE_EXPORT );
psa_set_key_algorithm( &attributes, KDF_ALG );
psa_set_key_type( &attributes, PSA_KEY_TYPE_DERIVE );
+ psa_set_key_bits( &attributes, PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ) );
/* For each label in turn, ... */
for( i = 0; i < ladder_depth; i++ )
@@ -306,10 +306,8 @@
*key_handle = 0;
/* Use the generator obtained from the parent key to create
* the next intermediate key. */
- PSA_CHECK( psa_generator_import_key(
- &attributes, key_handle,
- PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ),
- &generator ) );
+ PSA_CHECK( psa_generator_import_key( &attributes, key_handle,
+ &generator ) );
PSA_CHECK( psa_generator_abort( &generator ) );
}
@@ -336,6 +334,7 @@
psa_set_key_usage_flags( &attributes, usage );
psa_set_key_algorithm( &attributes, WRAPPING_ALG );
psa_set_key_type( &attributes, PSA_KEY_TYPE_AES );
+ psa_set_key_bits( &attributes, WRAPPING_KEY_BITS );
PSA_CHECK( psa_key_derivation(
&generator,
@@ -345,8 +344,7 @@
NULL, 0,
PSA_BITS_TO_BYTES( WRAPPING_KEY_BITS ) ) );
PSA_CHECK( psa_generator_import_key( &attributes, wrapping_key_handle,
- WRAPPING_KEY_BITS,
- &generator ) );
+ &generator ) );
exit:
psa_generator_abort( &generator );
diff --git a/tests/suites/test_suite_psa_crypto.data b/tests/suites/test_suite_psa_crypto.data
index 5b99b84..c91094c 100644
--- a/tests/suites/test_suite_psa_crypto.data
+++ b/tests/suites/test_suite_psa_crypto.data
@@ -2,7 +2,7 @@
static_checks:
PSA key attributes structure
-attributes_set_get:0x6963:PSA_KEY_LIFETIME_PERSISTENT:PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT:PSA_ALG_CCM:PSA_KEY_TYPE_AES
+attributes_set_get:0x6963:PSA_KEY_LIFETIME_PERSISTENT:PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT:PSA_ALG_CCM:PSA_KEY_TYPE_AES:128
PSA import/export raw: 0 bytes
import_export:"":PSA_KEY_TYPE_RAW_DATA:0:PSA_KEY_USAGE_EXPORT:0:0:PSA_SUCCESS:1
diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 1d67c6d..152f7e9 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -1157,7 +1157,7 @@
/* BEGIN_CASE */
void attributes_set_get( int id_arg, int lifetime_arg,
int usage_flags_arg, int alg_arg,
- int type_arg )
+ int type_arg, int bits_arg )
{
psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
psa_key_id_t id = id_arg;
@@ -1165,23 +1165,27 @@
psa_key_usage_t usage_flags = usage_flags_arg;
psa_algorithm_t alg = alg_arg;
psa_key_type_t type = type_arg;
+ size_t bits = bits_arg;
TEST_EQUAL( psa_get_key_id( &attributes ), 0 );
TEST_EQUAL( psa_get_key_lifetime( &attributes ), 0 );
TEST_EQUAL( psa_get_key_usage_flags( &attributes ), 0 );
TEST_EQUAL( psa_get_key_algorithm( &attributes ), 0 );
TEST_EQUAL( psa_get_key_type( &attributes ), 0 );
+ TEST_EQUAL( psa_get_key_bits( &attributes ), 0 );
psa_make_key_persistent( &attributes, id, lifetime );
psa_set_key_usage_flags( &attributes, usage_flags );
psa_set_key_algorithm( &attributes, alg );
psa_set_key_type( &attributes, type );
+ psa_set_key_bits( &attributes, bits );
TEST_EQUAL( psa_get_key_id( &attributes ), id );
TEST_EQUAL( psa_get_key_lifetime( &attributes ), lifetime );
TEST_EQUAL( psa_get_key_usage_flags( &attributes ), usage_flags );
TEST_EQUAL( psa_get_key_algorithm( &attributes ), alg );
TEST_EQUAL( psa_get_key_type( &attributes ), type );
+ TEST_EQUAL( psa_get_key_bits( &attributes ), bits );
psa_reset_key_attributes( &attributes );
@@ -1190,6 +1194,7 @@
TEST_EQUAL( psa_get_key_usage_flags( &attributes ), 0 );
TEST_EQUAL( psa_get_key_algorithm( &attributes ), 0 );
TEST_EQUAL( psa_get_key_type( &attributes ), 0 );
+ TEST_EQUAL( psa_get_key_bits( &attributes ), 0 );
}
/* END_CASE */
@@ -4294,8 +4299,8 @@
psa_set_key_usage_flags( &attributes, derived_usage );
psa_set_key_algorithm( &attributes, derived_alg );
psa_set_key_type( &attributes, derived_type );
+ psa_set_key_bits( &attributes, derived_bits );
PSA_ASSERT( psa_generator_import_key( &attributes, &derived_handle,
- derived_bits,
&generator ) );
/* Test the key information */
@@ -4327,7 +4332,6 @@
psa_key_handle_t derived_handle = 0;
psa_algorithm_t alg = alg_arg;
size_t bytes1 = bytes1_arg;
- size_t derived_bits = PSA_BYTES_TO_BITS( bytes1 );
size_t bytes2 = bytes2_arg;
size_t capacity = bytes1 + bytes2;
psa_crypto_generator_t generator = PSA_CRYPTO_GENERATOR_INIT;
@@ -4365,16 +4369,16 @@
psa_set_key_usage_flags( &derived_attributes, PSA_KEY_USAGE_EXPORT );
psa_set_key_algorithm( &derived_attributes, 0 );
psa_set_key_type( &derived_attributes, PSA_KEY_TYPE_RAW_DATA );
+ psa_set_key_bits( &derived_attributes, PSA_BYTES_TO_BITS( bytes1 ) );
PSA_ASSERT( psa_generator_import_key( &derived_attributes, &derived_handle,
- derived_bits,
&generator ) );
PSA_ASSERT( psa_export_key( derived_handle,
export_buffer, bytes1,
&length ) );
TEST_EQUAL( length, bytes1 );
PSA_ASSERT( psa_destroy_key( derived_handle ) );
+ psa_set_key_bits( &derived_attributes, PSA_BYTES_TO_BITS( bytes2 ) );
PSA_ASSERT( psa_generator_import_key( &derived_attributes, &derived_handle,
- PSA_BYTES_TO_BITS( bytes2 ),
&generator ) );
PSA_ASSERT( psa_export_key( derived_handle,
export_buffer + bytes1, bytes2,
@@ -4667,9 +4671,10 @@
psa_set_key_usage_flags( &attributes, usage );
psa_set_key_algorithm( &attributes, alg );
psa_set_key_type( &attributes, type );
+ psa_set_key_bits( &attributes, bits );
/* Generate a key */
- TEST_EQUAL( psa_generate_key( &attributes, &handle, bits, NULL, 0 ),
+ TEST_EQUAL( psa_generate_key( &attributes, &handle, NULL, 0 ),
expected_status );
if( expected_info_status != PSA_SUCCESS )
goto exit;
@@ -4722,6 +4727,7 @@
psa_set_key_usage_flags( &attributes, usage_flags );
psa_set_key_algorithm( &attributes, alg );
psa_set_key_type( &attributes, type );
+ psa_set_key_bits( &attributes, bits );
switch( generation_method )
{
@@ -4733,8 +4739,7 @@
case GENERATE_KEY:
/* Generate a key */
- PSA_ASSERT( psa_generate_key( &attributes, &handle,
- bits, NULL, 0 ) );
+ PSA_ASSERT( psa_generate_key( &attributes, &handle, NULL, 0 ) );
break;
case DERIVE_KEY:
@@ -4757,7 +4762,7 @@
&generator, PSA_KDF_STEP_INFO,
NULL, 0 ) );
PSA_ASSERT( psa_generator_import_key( &attributes, &handle,
- bits, &generator ) );
+ &generator ) );
PSA_ASSERT( psa_generator_abort( &generator ) );
PSA_ASSERT( psa_destroy_key( base_key ) );
base_key = 0;