Implement, plug in and test validate_key driver entry point

Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>

library/psa_crypto.c

@@ -977,6 +977,7 @@ psa_status_t psa_import_key_into_slot( psa_key_slot_t *slot,
                                        size_t data_length )
 {
     psa_status_t status = PSA_SUCCESS;
+    size_t bit_size;
 
     /* zero-length keys are never supported. */
     if( data_length == 0 )
@@ -984,7 +985,7 @@ psa_status_t psa_import_key_into_slot( psa_key_slot_t *slot,
 
     if( key_type_is_raw_bytes( slot->attr.type ) )
     {
-        size_t bit_size = PSA_BYTES_TO_BITS( data_length );
+        bit_size = PSA_BYTES_TO_BITS( data_length );
 
         /* Ensure that the bytes-to-bits conversion hasn't overflown. */
         if( data_length > SIZE_MAX / 8 )

library/psa_crypto_driver_wrappers.c

@@ -410,6 +410,34 @@ psa_status_t psa_driver_wrapper_generate_key( const psa_key_attributes_t *attrib
 #endif /* PSA_CRYPTO_DRIVER_PRESENT */
 }
 
+psa_status_t psa_driver_wrapper_validate_key( const psa_key_attributes_t *attributes,
+                                              const uint8_t *data,
+                                              size_t data_length,
+                                              size_t *bits )
+{
+#if defined(PSA_CRYPTO_ACCELERATOR_DRIVER_PRESENT)
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    /* Try accelerators in turn */
+#if defined(PSA_CRYPTO_DRIVER_TEST)
+    status = test_transparent_validate_key( attributes,
+                                            data,
+                                            data_length,
+                                            bits );
+    /* Declared with fallback == true */
+    if( status != PSA_ERROR_NOT_SUPPORTED )
+        return( status );
+#endif /* PSA_CRYPTO_DRIVER_TEST */
+
+    return( PSA_ERROR_NOT_SUPPORTED );
+#else /* PSA_CRYPTO_ACCELERATOR_DRIVER_PRESENT */
+    (void) attributes;
+    (void) data;
+    (void) data_length;
+    (void) bits;
+    return( PSA_ERROR_NOT_SUPPORTED );
+#endif /* PSA_CRYPTO_DRIVER_PRESENT */
+}
+
 /*
  * Cipher functions
  */

library/psa_crypto_driver_wrappers.h

@@ -43,9 +43,18 @@ psa_status_t psa_driver_wrapper_verify_hash( psa_key_slot_t *slot,
                                              const uint8_t *signature,
                                              size_t signature_length );
 
+/*
+ * Key handling functions
+ */
+
 psa_status_t psa_driver_wrapper_generate_key( const psa_key_attributes_t *attributes,
                                               psa_key_slot_t *slot );
 
+psa_status_t psa_driver_wrapper_validate_key( const psa_key_attributes_t *attributes,
+                                              const uint8_t *data,
+                                              size_t data_length,
+                                              size_t *bits );
+
 /*
  * Cipher functions
  */

tests/include/test/drivers/keygen.h

@@ -1,5 +1,5 @@
 /*
- * Test driver for generating keys.
+ * Test driver for generating and verifying keys.
  */
 /*  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
@@ -57,5 +57,10 @@ psa_status_t test_opaque_generate_key(
     const psa_key_attributes_t *attributes,
     uint8_t *key, size_t key_size, size_t *key_length );
 
+psa_status_t test_transparent_validate_key(const psa_key_attributes_t *attributes,
+                                           const uint8_t *data,
+                                           size_t data_length,
+                                           size_t *bits);
+
 #endif /* PSA_CRYPTO_DRIVER_TEST */
 #endif /* PSA_CRYPTO_TEST_DRIVERS_KEYGEN_H */

tests/src/drivers/keygen.c

@@ -1,6 +1,6 @@
 /*
- * Test driver for generating keys.
+ * Test driver for generating and verifying keys.
- * Currently only supports generating ECC keys.
+ * Currently only supports generating and verifying ECC keys.
  */
 /*  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
@@ -122,4 +122,112 @@ psa_status_t test_opaque_generate_key(
     return( PSA_ERROR_NOT_SUPPORTED );
 }
 
+psa_status_t test_transparent_validate_key(const psa_key_attributes_t *attributes,
+                                           const uint8_t *data,
+                                           size_t data_length,
+                                           size_t *bits)
+{
+    ++test_driver_keygen_hooks.hits;
+
+    if( test_driver_keygen_hooks.forced_status != PSA_SUCCESS )
+        return( test_driver_keygen_hooks.forced_status );
+
+#if defined(MBEDTLS_ECP_C)
+    psa_key_type_t type = psa_get_key_type( attributes );
+    if ( PSA_KEY_TYPE_IS_ECC( type ) )
+    {
+        // Code mostly copied from psa_load_ecp_representation
+        psa_ecc_family_t curve = PSA_KEY_TYPE_ECC_GET_FAMILY( type );
+        mbedtls_ecp_group_id grp_id;
+        mbedtls_ecp_keypair ecp;
+        psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+        if( *bits == 0 )
+        {
+            // Attempt auto-detect of curve bit size
+            size_t curve_size = data_length;
+
+            if( PSA_KEY_TYPE_IS_PUBLIC_KEY( type ) &&
+                PSA_KEY_TYPE_ECC_GET_FAMILY( type ) != PSA_ECC_FAMILY_MONTGOMERY )
+            {
+                /* A Weierstrass public key is represented as:
+                 * - The byte 0x04;
+                 * - `x_P` as a `ceiling(m/8)`-byte string, big-endian;
+                 * - `y_P` as a `ceiling(m/8)`-byte string, big-endian.
+                 * So its data length is 2m+1 where n is the key size in bits.
+                 */
+                if( ( data_length & 1 ) == 0 )
+                    return( PSA_ERROR_INVALID_ARGUMENT );
+                curve_size = data_length / 2;
+
+                /* Montgomery public keys are represented in compressed format, meaning
+                 * their curve_size is equal to the amount of input. */
+
+                /* Private keys are represented in uncompressed private random integer
+                 * format, meaning their curve_size is equal to the amount of input. */
+            }
+
+            grp_id = mbedtls_ecc_group_of_psa( curve, curve_size );
+        }
+        else
+        {
+            grp_id = mbedtls_ecc_group_of_psa( curve,
+                PSA_BITS_TO_BYTES( psa_get_key_bits( attributes ) ) );
+        }
+
+        const mbedtls_ecp_curve_info *curve_info =
+            mbedtls_ecp_curve_info_from_grp_id( grp_id );
+
+        if( attributes->domain_parameters_size != 0 )
+            return( PSA_ERROR_NOT_SUPPORTED );
+        if( grp_id == MBEDTLS_ECP_DP_NONE || curve_info == NULL )
+            return( PSA_ERROR_NOT_SUPPORTED );
+
+        *bits = curve_info->bit_size;
+
+        mbedtls_ecp_keypair_init( &ecp );
+
+        status = mbedtls_to_psa_error(
+                    mbedtls_ecp_group_load( &ecp.grp, grp_id ) );
+        if( status != PSA_SUCCESS )
+            goto ecp_exit;
+
+        /* Load the key material. */
+        if( PSA_KEY_TYPE_IS_PUBLIC_KEY( type ) )
+        {
+            /* Load the public value. */
+            status = mbedtls_to_psa_error(
+                mbedtls_ecp_point_read_binary( &ecp.grp, &ecp.Q,
+                                               data,
+                                               data_length ) );
+            if( status != PSA_SUCCESS )
+                goto ecp_exit;
+
+            /* Check that the point is on the curve. */
+            status = mbedtls_to_psa_error(
+                mbedtls_ecp_check_pubkey( &ecp.grp, &ecp.Q ) );
+        }
+        else
+        {
+            /* Load and validate the secret value. */
+            status = mbedtls_to_psa_error(
+                mbedtls_ecp_read_key( ecp.grp.id,
+                                      &ecp,
+                                      data,
+                                      data_length ) );
+        }
+
+ecp_exit:
+        mbedtls_ecp_keypair_free( &ecp );
+        return( status );
+    }
+    return( PSA_ERROR_NOT_SUPPORTED );
+#else
+    (void) data;
+    (void) data_length;
+    (void) bits;
+    return( PSA_ERROR_NOT_SUPPORTED );
+#endif /* MBEDTLS_ECP_C */
+}
+
 #endif /* MBEDTLS_PSA_CRYPTO_DRIVERS && PSA_CRYPTO_DRIVER_TEST */

tests/suites/test_suite_psa_crypto_driver_wrappers.data

@@ -40,6 +40,25 @@ generate_key:PSA_ERROR_NOT_SUPPORTED:"":PSA_SUCCESS
 generate_key through transparent driver: error
 generate_key:PSA_ERROR_GENERIC_ERROR:"":PSA_ERROR_GENERIC_ERROR
 
+validate key through transparent driver: good private key
+depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_PK_WRITE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+validate_key:PSA_SUCCESS:PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_FAMILY_SECP_R1):"49c9a8c18c4b885638c431cf1df1c994131609b580d4fd43a0cab17db2f13eee":PSA_SUCCESS
+
+validate key through transparent driver: good public key
+depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_PK_WRITE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+validate_key:PSA_SUCCESS:PSA_KEY_TYPE_ECC_PUBLIC_KEY(PSA_ECC_FAMILY_SECP_R1):"04dea5e45d0ea37fc566232a508f4ad20ea13d47e4bf5fa4d54a57a0ba012042087097496efc583fed8b24a5b9be9a51de063f5a00a8b698a16fd7f29b5485f320":PSA_SUCCESS
+
+validate key through transparent driver: fallback private key
+depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_PK_WRITE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+validate_key:PSA_ERROR_NOT_SUPPORTED:PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_FAMILY_SECP_R1):"49c9a8c18c4b885638c431cf1df1c994131609b580d4fd43a0cab17db2f13eee":PSA_SUCCESS
+
+validate key through transparent driver: fallback public key
+depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_PK_WRITE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+validate_key:PSA_ERROR_NOT_SUPPORTED:PSA_KEY_TYPE_ECC_PUBLIC_KEY(PSA_ECC_FAMILY_SECP_R1):"04dea5e45d0ea37fc566232a508f4ad20ea13d47e4bf5fa4d54a57a0ba012042087097496efc583fed8b24a5b9be9a51de063f5a00a8b698a16fd7f29b5485f320":PSA_SUCCESS
+
+validate key through transparent driver: error
+validate_key:PSA_ERROR_GENERIC_ERROR:PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_FAMILY_SECP_R1):"49c9a8c18c4b885638c431cf1df1c994131609b580d4fd43a0cab17db2f13eee":PSA_ERROR_GENERIC_ERROR
+
 PSA symmetric encrypt: AES-CTR, 16 bytes, good
 depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CTR
 cipher_encrypt:PSA_ALG_CTR:PSA_KEY_TYPE_AES:"2b7e151628aed2a6abf7158809cf4f3c":"2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a":"6bc1bee22e409f96e93d7e117393172a":"8f9408fe80a81d3e813da3c7b0b2bd32":0:PSA_SUCCESS:PSA_SUCCESS

tests/suites/test_suite_psa_crypto_driver_wrappers.function

@@ -184,6 +184,40 @@ exit:
 }
 /* END_CASE */
 
+/* BEGIN_CASE depends_on:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED */
+void validate_key( int force_status_arg,
+                   int key_type_arg,
+                   data_t *key_input,
+                   int expected_status_arg )
+{
+    psa_status_t force_status = force_status_arg;
+    psa_status_t expected_status = expected_status_arg;
+    psa_key_type_t key_type = key_type_arg;
+    psa_key_handle_t handle = 0;
+    psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
+    psa_status_t actual_status;
+    test_driver_keygen_hooks = test_driver_keygen_hooks_init();
+
+    psa_set_key_type( &attributes,
+                      key_type );
+    psa_set_key_bits( &attributes, 0 );
+    psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_EXPORT );
+
+    test_driver_keygen_hooks.forced_status = force_status;
+
+    PSA_ASSERT( psa_crypto_init( ) );
+
+    actual_status = psa_import_key( &attributes, key_input->x, key_input->len, &handle );
+    TEST_EQUAL( test_driver_keygen_hooks.hits, 1 );
+    TEST_EQUAL( actual_status, expected_status );
+exit:
+    psa_reset_key_attributes( &attributes );
+    psa_destroy_key( handle );
+    PSA_DONE( );
+    test_driver_keygen_hooks = test_driver_keygen_hooks_init();
+}
+/* END_CASE */
+
 /* BEGIN_CASE */
 void cipher_encrypt( int alg_arg, int key_type_arg,
                      data_t *key, data_t *iv,