aead: Support custom AEAD salt sizes

The salt, or often called implicit nonce, varies between AEAD algorithms and
their use in protocols. For IKE and ESP, GCM uses 4 bytes, while CCM uses
3 bytes. With TLS, however, AEAD mode uses 4 bytes for both GCM and CCM.

Our GCM backends currently support 4 bytes and CCM 3 bytes only. This is fine
until we go for CCM mode support in TLS, which requires 4 byte nonces.

scripts/aes-test.c

@@ -313,7 +313,7 @@ static bool do_test_gcm(test_vector_t *test)
 			return FALSE;
 	}
 
-	aead = lib->crypto->create_aead(lib->crypto, alg, test->key.len);
+	aead = lib->crypto->create_aead(lib->crypto, alg, test->key.len, 4);
 	if (!aead)
 	{
 		DBG1(DBG_APP, "algorithm %N or key length (%d bits) not supported",

scripts/crypt_burn.c

@@ -61,7 +61,7 @@ int main(int argc, char *argv[])
 	if (encryption_algorithm_is_aead(token->algorithm))
 	{
 		aead = lib->crypto->create_aead(lib->crypto,
-										token->algorithm, token->keysize / 8);
+									token->algorithm, token->keysize / 8, 0);
 		if (!aead)
 		{
 			fprintf(stderr, "aead '%s' not supported!\n", argv[1]);