crypto: separate cipher/MAC availability check from information request

1 files changed, 15 insertions, 18 deletions

diff --git a/src/methods/generic_poly1305/generic_poly1305.c b/src/methods/generic_poly1305/generic_poly1305.c
index 3820907..80ced8c 100644
--- a/src/methods/generic_poly1305/generic_poly1305.c
+++ b/src/methods/generic_poly1305/generic_poly1305.c
@@ -43,7 +43,7 @@ struct fastd_method_session_state {
 };
 
 
-static bool cipher_get(fastd_context_t *ctx, const char *name, const fastd_cipher_info_t **cipher_info, const fastd_cipher_t **cipher, const fastd_cipher_context_t **cctx) {
+static bool cipher_get(fastd_context_t *ctx, const char *name, const fastd_cipher_info_t **cipher_info, const fastd_cipher_t **cipher, const fastd_cipher_context_t **cctx, bool check) {
 	size_t len = strlen(name);
 
 	if (len < 9)
@@ -56,31 +56,28 @@ static bool cipher_get(fastd_context_t *ctx, const char *name, const fastd_ciphe
 	memcpy(cipher_name, name, len-9);
 	cipher_name[len-9] = 0;
 
-	const fastd_cipher_info_t *info = NULL;
-
-	if (ctx) {
-		*cipher = fastd_cipher_get_by_name(ctx, cipher_name, &info, cctx);
-		if (!*cipher)
-			return false;
-	}
-	else {
-		info = fastd_cipher_info_get_by_name(cipher_name);
-		if (!info)
-			return false;
-	}
-
-	if (info->iv_length <= COMMON_NONCEBYTES)
+	if (check && !fastd_cipher_is_available(cipher_name))
 		return false;
 
-	if (cipher_info)
-		*cipher_info = info;
+	if (ctx)
+		*cipher = fastd_cipher_get_by_name(ctx, cipher_name, cipher_info, cctx);
+	else if (cipher_info)
+		*cipher_info = fastd_cipher_info_get_by_name(cipher_name);
 
 	return true;
 }
 
 
 static bool method_provides(const char *name) {
-	return cipher_get(NULL, name, NULL, NULL, NULL);
+	const fastd_cipher_info_t *cipher_info;
+
+	if (!cipher_get(NULL, name, &cipher_info, NULL, NULL, true))
+		return false;
+
+	if (cipher_info->iv_length <= COMMON_NONCEBYTES)
+		return false;
+
+	return true;
 }
 
 static size_t method_key_length(fastd_context_t *ctx, const char *name) {