Move RSA key generation code to the PSA RSA specific C file

Signed-off-by: Ronald Cron <ronald.cron@arm.com>

library/psa_crypto.c

@@ -5956,34 +5956,6 @@ psa_status_t mbedtls_psa_inject_entropy( const uint8_t *seed,
 }
 #endif /* MBEDTLS_PSA_INJECT_ENTROPY */
 
-#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR)
-static psa_status_t psa_read_rsa_exponent( const uint8_t *domain_parameters,
-                                           size_t domain_parameters_size,
-                                           int *exponent )
-{
-    size_t i;
-    uint32_t acc = 0;
-
-    if( domain_parameters_size == 0 )
-    {
-        *exponent = 65537;
-        return( PSA_SUCCESS );
-    }
-
-    /* Mbed TLS encodes the public exponent as an int. For simplicity, only
-     * support values that fit in a 32-bit integer, which is larger than
-     * int on just about every platform anyway. */
-    if( domain_parameters_size > sizeof( acc ) )
-        return( PSA_ERROR_NOT_SUPPORTED );
-    for( i = 0; i < domain_parameters_size; i++ )
-        acc = ( acc << 8 ) | domain_parameters[i];
-    if( acc > INT_MAX )
-        return( PSA_ERROR_NOT_SUPPORTED );
-    *exponent = acc;
-    return( PSA_SUCCESS );
-}
-#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) */
-
 /** Get the key buffer size for the key material in export format
  *
  * \param[in] type  The key type
@@ -6070,33 +6042,10 @@ psa_status_t psa_generate_key_internal(
 #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR)
     if ( type == PSA_KEY_TYPE_RSA_KEY_PAIR )
     {
-        mbedtls_rsa_context rsa;
+        return( mbedtls_psa_rsa_generate_key( attributes,
-        int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+                                              key_buffer,
-        int exponent;
+                                              key_buffer_size,
-
+                                              key_buffer_length ) );
-        status = psa_read_rsa_exponent( attributes->domain_parameters,
-                                        attributes->domain_parameters_size,
-                                        &exponent );
-        if( status != PSA_SUCCESS )
-            return( status );
-
-        mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, MBEDTLS_MD_NONE );
-        ret = mbedtls_rsa_gen_key( &rsa,
-                                   mbedtls_psa_get_random,
-                                   MBEDTLS_PSA_RANDOM_STATE,
-                                   (unsigned int) attributes->core.bits,
-                                   exponent );
-        if( ret != 0 )
-            return( mbedtls_to_psa_error( ret ) );
-
-        status = mbedtls_psa_rsa_export_key( type,
-                                             &rsa,
-                                             key_buffer,
-                                             key_buffer_size,
-                                             key_buffer_length );
-        mbedtls_rsa_free( &rsa );
-
-        return( status );
     }
     else
 #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) */

library/psa_crypto_rsa.c

@@ -24,6 +24,7 @@
 
 #include <psa/crypto.h>
 #include "psa_crypto_core.h"
+#include "psa_crypto_random_impl.h"
 #include "psa_crypto_rsa.h"
 
 #include <stdlib.h>
@@ -258,6 +259,66 @@ static psa_status_t rsa_export_public_key(
 #endif /* defined(BUILTIN_KEY_TYPE_RSA_KEY_PAIR) ||
         * defined(BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */
 
+#if defined(BUILTIN_KEY_TYPE_RSA_KEY_PAIR)
+static psa_status_t psa_read_rsa_exponent( const uint8_t *domain_parameters,
+                                           size_t domain_parameters_size,
+                                           int *exponent )
+{
+    size_t i;
+    uint32_t acc = 0;
+
+    if( domain_parameters_size == 0 )
+    {
+        *exponent = 65537;
+        return( PSA_SUCCESS );
+    }
+
+    /* Mbed TLS encodes the public exponent as an int. For simplicity, only
+     * support values that fit in a 32-bit integer, which is larger than
+     * int on just about every platform anyway. */
+    if( domain_parameters_size > sizeof( acc ) )
+        return( PSA_ERROR_NOT_SUPPORTED );
+    for( i = 0; i < domain_parameters_size; i++ )
+        acc = ( acc << 8 ) | domain_parameters[i];
+    if( acc > INT_MAX )
+        return( PSA_ERROR_NOT_SUPPORTED );
+    *exponent = acc;
+    return( PSA_SUCCESS );
+}
+
+psa_status_t mbedtls_psa_rsa_generate_key(
+    const psa_key_attributes_t *attributes,
+    uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length )
+{
+    psa_status_t status;
+    mbedtls_rsa_context rsa;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    int exponent;
+
+    status = psa_read_rsa_exponent( attributes->domain_parameters,
+                                    attributes->domain_parameters_size,
+                                    &exponent );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, MBEDTLS_MD_NONE );
+    ret = mbedtls_rsa_gen_key( &rsa,
+                               mbedtls_psa_get_random,
+                               MBEDTLS_PSA_RANDOM_STATE,
+                               (unsigned int)attributes->core.bits,
+                               exponent );
+    if( ret != 0 )
+        return( mbedtls_to_psa_error( ret ) );
+
+    status = mbedtls_psa_rsa_export_key( attributes->core.type,
+                                         &rsa, key_buffer, key_buffer_size,
+                                         key_buffer_length );
+    mbedtls_rsa_free( &rsa );
+
+    return( status );
+}
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) */
+
 #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \
     defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY)
 

library/psa_crypto_rsa.h

@@ -114,6 +114,29 @@ psa_status_t mbedtls_psa_rsa_export_public_key(
     const uint8_t *key_buffer, size_t key_buffer_size,
     uint8_t *data, size_t data_size, size_t *data_length );
 
+/**
+ * \brief Generate an RSA key.
+ *
+ * \note The signature of the function is that of a PSA driver generate_key
+ *       entry point.
+ *
+ * \param[in]  attributes         The attributes for the RSA key to generate.
+ * \param[out] key_buffer         Buffer where the key data is to be written.
+ * \param[in]  key_buffer_size    Size of \p key_buffer in bytes.
+ * \param[out] key_buffer_length  On success, the number of bytes written in
+ *                                \p key_buffer.
+ *
+ * \retval #PSA_SUCCESS
+ *         The key was successfully generated.
+ * \retval #PSA_ERROR_NOT_SUPPORTED
+ *         Key length or type not supported.
+ * \retval #PSA_ERROR_BUFFER_TOO_SMALL
+ *         The size of \p key_buffer is too small.
+ */
+psa_status_t mbedtls_psa_rsa_generate_key(
+    const psa_key_attributes_t *attributes,
+    uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length );
+
 /*
  * BEYOND THIS POINT, TEST DRIVER ENTRY POINTS ONLY.
  */