Allow arbitrary length responses from ckdb in send_recv_auth to allow for hundreds of workers

src/stratifier.c

@@ -2390,13 +2390,16 @@ static int send_recv_auth(stratum_instance_t *client)
 
 	free(json_msg);
 	if (likely(buf)) {
+		char *cmd = NULL, *secondaryuserid = NULL, *response;
 		worker_instance_t *worker = client->worker_instance;
-		char *cmd = NULL, *secondaryuserid = NULL;
-		char response[PAGESIZE] = {};
 		json_error_t err_val;
+		size_t responselen;
 		json_t *val = NULL;
 
 		LOGINFO("Got ckdb response: %s", buf);
+		responselen = strlen(buf); /* Leave ample room for response based on buf length */
+		response = alloca(responselen);
+		memset(response, 0, responselen);
 		if (unlikely(sscanf(buf, "id.%*d.%s", response) < 1 || strlen(response) < 1 || !strchr(response, '='))) {
 			if (cmdmatch(response, "failed"))
 				goto out;