psa: aead: Move AEAD driver entry points to psa_crypto_aead.c

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/psa_crypto_aead.c b/library/psa_crypto_aead.c
index f453533..18ea176 100644
--- a/library/psa_crypto_aead.c
+++ b/library/psa_crypto_aead.c
@@ -23,6 +23,336 @@
 #if defined(MBEDTLS_PSA_CRYPTO_C)
 
 #include "psa_crypto_aead.h"
+#include "psa_crypto_core.h"
+
+#include "mbedtls/ccm.h"
+#include "mbedtls/chachapoly.h"
+#include "mbedtls/cipher.h"
+#include "mbedtls/gcm.h"
+
+typedef struct
+{
+    const mbedtls_cipher_info_t *cipher_info;
+    union
+    {
+        unsigned dummy; /* Make the union non-empty even with no supported algorithms. */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
+        mbedtls_ccm_context ccm;
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
+        mbedtls_gcm_context gcm;
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305)
+        mbedtls_chachapoly_context chachapoly;
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */
+    } ctx;
+    psa_algorithm_t core_alg;
+    uint8_t full_tag_length;
+    uint8_t tag_length;
+} aead_operation_t;
+
+#define AEAD_OPERATION_INIT {0, {0}, 0, 0, 0}
+
+static void psa_aead_abort_internal( aead_operation_t *operation )
+{
+    switch( operation->core_alg )
+    {
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
+        case PSA_ALG_CCM:
+            mbedtls_ccm_free( &operation->ctx.ccm );
+            break;
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
+        case PSA_ALG_GCM:
+            mbedtls_gcm_free( &operation->ctx.gcm );
+            break;
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
+    }
+}
+
+static psa_status_t psa_aead_setup(
+    aead_operation_t *operation,
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer,
+    psa_algorithm_t alg )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    size_t key_bits;
+    mbedtls_cipher_id_t cipher_id;
+
+    key_bits = attributes->core.bits;
+
+    operation->cipher_info =
+        mbedtls_cipher_info_from_psa( alg, attributes->core.type, key_bits,
+                                      &cipher_id );
+    if( operation->cipher_info == NULL )
+        return( PSA_ERROR_NOT_SUPPORTED );
+
+    switch( PSA_ALG_AEAD_WITH_SHORTENED_TAG( alg, 0 ) )
+    {
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
+        case PSA_ALG_AEAD_WITH_SHORTENED_TAG( PSA_ALG_CCM, 0 ):
+            operation->core_alg = PSA_ALG_CCM;
+            operation->full_tag_length = 16;
+            /* CCM allows the following tag lengths: 4, 6, 8, 10, 12, 14, 16.
+             * The call to mbedtls_ccm_encrypt_and_tag or
+             * mbedtls_ccm_auth_decrypt will validate the tag length. */
+            if( PSA_BLOCK_CIPHER_BLOCK_LENGTH( attributes->core.type ) != 16 )
+                return( PSA_ERROR_INVALID_ARGUMENT );
+
+            mbedtls_ccm_init( &operation->ctx.ccm );
+            status = mbedtls_to_psa_error(
+                mbedtls_ccm_setkey( &operation->ctx.ccm, cipher_id,
+                                    key_buffer, (unsigned int) key_bits ) );
+            if( status != PSA_SUCCESS )
+                return( status );
+            break;
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
+        case PSA_ALG_AEAD_WITH_SHORTENED_TAG( PSA_ALG_GCM, 0 ):
+            operation->core_alg = PSA_ALG_GCM;
+            operation->full_tag_length = 16;
+            /* GCM allows the following tag lengths: 4, 8, 12, 13, 14, 15, 16.
+             * The call to mbedtls_gcm_crypt_and_tag or
+             * mbedtls_gcm_auth_decrypt will validate the tag length. */
+            if( PSA_BLOCK_CIPHER_BLOCK_LENGTH( attributes->core.type ) != 16 )
+                return( PSA_ERROR_INVALID_ARGUMENT );
+
+            mbedtls_gcm_init( &operation->ctx.gcm );
+            status = mbedtls_to_psa_error(
+                mbedtls_gcm_setkey( &operation->ctx.gcm, cipher_id,
+                                    key_buffer, (unsigned int) key_bits ) );
+            if( status != PSA_SUCCESS )
+                return( status );
+            break;
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305)
+        case PSA_ALG_AEAD_WITH_SHORTENED_TAG( PSA_ALG_CHACHA20_POLY1305, 0 ):
+            operation->core_alg = PSA_ALG_CHACHA20_POLY1305;
+            operation->full_tag_length = 16;
+            /* We only support the default tag length. */
+            if( alg != PSA_ALG_CHACHA20_POLY1305 )
+                return( PSA_ERROR_NOT_SUPPORTED );
+
+            mbedtls_chachapoly_init( &operation->ctx.chachapoly );
+            status = mbedtls_to_psa_error(
+                mbedtls_chachapoly_setkey( &operation->ctx.chachapoly,
+                                           key_buffer ) );
+            if( status != PSA_SUCCESS )
+                return( status );
+            break;
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */
+
+        default:
+            return( PSA_ERROR_NOT_SUPPORTED );
+    }
+
+    if( PSA_AEAD_TAG_LENGTH( alg ) > operation->full_tag_length )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    operation->tag_length = PSA_AEAD_TAG_LENGTH( alg );
+
+    return( PSA_SUCCESS );
+}
+
+psa_status_t mbedtls_psa_aead_encrypt(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    psa_algorithm_t alg,
+    const uint8_t *nonce, size_t nonce_length,
+    const uint8_t *additional_data, size_t additional_data_length,
+    const uint8_t *plaintext, size_t plaintext_length,
+    uint8_t *ciphertext, size_t ciphertext_size, size_t *ciphertext_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    aead_operation_t operation = AEAD_OPERATION_INIT;
+    uint8_t *tag;
+    (void) key_buffer_size;
+
+    status = psa_aead_setup( &operation, attributes, key_buffer, alg );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    /* For all currently supported modes, the tag is at the end of the
+     * ciphertext. */
+    if( ciphertext_size < ( plaintext_length + operation.tag_length ) )
+    {
+        status = PSA_ERROR_BUFFER_TOO_SMALL;
+        goto exit;
+    }
+    tag = ciphertext + plaintext_length;
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
+    if( operation.core_alg == PSA_ALG_GCM )
+    {
+        status = mbedtls_to_psa_error(
+            mbedtls_gcm_crypt_and_tag( &operation.ctx.gcm,
+                                       MBEDTLS_GCM_ENCRYPT,
+                                       plaintext_length,
+                                       nonce, nonce_length,
+                                       additional_data, additional_data_length,
+                                       plaintext, ciphertext,
+                                       operation.tag_length, tag ) );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
+    if( operation.core_alg == PSA_ALG_CCM )
+    {
+        status = mbedtls_to_psa_error(
+            mbedtls_ccm_encrypt_and_tag( &operation.ctx.ccm,
+                                         plaintext_length,
+                                         nonce, nonce_length,
+                                         additional_data,
+                                         additional_data_length,
+                                         plaintext, ciphertext,
+                                         tag, operation.tag_length ) );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305)
+    if( operation.core_alg == PSA_ALG_CHACHA20_POLY1305 )
+    {
+        if( nonce_length != 12 || operation.tag_length != 16 )
+        {
+            status = PSA_ERROR_NOT_SUPPORTED;
+            goto exit;
+        }
+        status = mbedtls_to_psa_error(
+            mbedtls_chachapoly_encrypt_and_tag( &operation.ctx.chachapoly,
+                                                plaintext_length,
+                                                nonce,
+                                                additional_data,
+                                                additional_data_length,
+                                                plaintext,
+                                                ciphertext,
+                                                tag ) );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */
+    {
+        (void) tag;
+        return( PSA_ERROR_NOT_SUPPORTED );
+    }
+
+    if( status == PSA_SUCCESS )
+        *ciphertext_length = plaintext_length + operation.tag_length;
+
+exit:
+    psa_aead_abort_internal( &operation );
+
+    return( status );
+}
+
+/* Locate the tag in a ciphertext buffer containing the encrypted data
+ * followed by the tag. Return the length of the part preceding the tag in
+ * *plaintext_length. This is the size of the plaintext in modes where
+ * the encrypted data has the same size as the plaintext, such as
+ * CCM and GCM. */
+static psa_status_t psa_aead_unpadded_locate_tag( size_t tag_length,
+                                                  const uint8_t *ciphertext,
+                                                  size_t ciphertext_length,
+                                                  size_t plaintext_size,
+                                                  const uint8_t **p_tag )
+{
+    size_t payload_length;
+    if( tag_length > ciphertext_length )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    payload_length = ciphertext_length - tag_length;
+    if( payload_length > plaintext_size )
+        return( PSA_ERROR_BUFFER_TOO_SMALL );
+    *p_tag = ciphertext + payload_length;
+    return( PSA_SUCCESS );
+}
+
+psa_status_t mbedtls_psa_aead_decrypt(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    psa_algorithm_t alg,
+    const uint8_t *nonce, size_t nonce_length,
+    const uint8_t *additional_data, size_t additional_data_length,
+    const uint8_t *ciphertext, size_t ciphertext_length,
+    uint8_t *plaintext, size_t plaintext_size, size_t *plaintext_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    aead_operation_t operation = AEAD_OPERATION_INIT;
+    const uint8_t *tag = NULL;
+    (void) key_buffer_size;
+
+    status = psa_aead_setup( &operation, attributes, key_buffer, alg );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = psa_aead_unpadded_locate_tag( operation.tag_length,
+                                           ciphertext, ciphertext_length,
+                                           plaintext_size, &tag );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
+    if( operation.core_alg == PSA_ALG_GCM )
+    {
+        status = mbedtls_to_psa_error(
+            mbedtls_gcm_auth_decrypt( &operation.ctx.gcm,
+                                      ciphertext_length - operation.tag_length,
+                                      nonce, nonce_length,
+                                      additional_data,
+                                      additional_data_length,
+                                      tag, operation.tag_length,
+                                      ciphertext, plaintext ) );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
+    if( operation.core_alg == PSA_ALG_CCM )
+    {
+        status = mbedtls_to_psa_error(
+            mbedtls_ccm_auth_decrypt( &operation.ctx.ccm,
+                                      ciphertext_length - operation.tag_length,
+                                      nonce, nonce_length,
+                                      additional_data,
+                                      additional_data_length,
+                                      ciphertext, plaintext,
+                                      tag, operation.tag_length ) );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305)
+    if( operation.core_alg == PSA_ALG_CHACHA20_POLY1305 )
+    {
+        if( nonce_length != 12 || operation.tag_length != 16 )
+        {
+            status = PSA_ERROR_NOT_SUPPORTED;
+            goto exit;
+        }
+        status = mbedtls_to_psa_error(
+            mbedtls_chachapoly_auth_decrypt( &operation.ctx.chachapoly,
+                                             ciphertext_length - operation.tag_length,
+                                             nonce,
+                                             additional_data,
+                                             additional_data_length,
+                                             tag,
+                                             ciphertext,
+                                             plaintext ) );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */
+    {
+        return( PSA_ERROR_NOT_SUPPORTED );
+    }
+
+    if( status == PSA_SUCCESS )
+        *plaintext_length = ciphertext_length - operation.tag_length;
+
+exit:
+    psa_aead_abort_internal( &operation );
+
+    if( status == PSA_SUCCESS )
+        *plaintext_length = ciphertext_length - operation.tag_length;
+    return( status );
+}
 
 #endif /* MBEDTLS_PSA_CRYPTO_C */