From d04b155e118403eaf3d8cb6cf61a25af709a4f90 Mon Sep 17 00:00:00 2001
From: Overtorment <overtorment@gmail.com>
Date: Fri, 1 Feb 2019 19:06:47 +0000
Subject: [PATCH] FIX: can pay negative free amount invoices

---
 controllers/api.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/controllers/api.js b/controllers/api.js
index dba719d..189d70c 100644
--- a/controllers/api.js
+++ b/controllers/api.js
@@ -112,7 +112,10 @@ router.post('/payinvoice', async function(req, res) {
 
   if (!req.body.invoice) return errorBadArguments(res);
   let freeAmount = false;
-  if (req.body.amount) freeAmount = parseInt(req.body.amount);
+  if (req.body.amount) {
+    freeAmount = parseInt(req.body.amount);
+    if (freeAmount <= 0) return errorBadArguments(res);
+  }
 
   // obtaining a lock
   let lock = new Lock(redis, 'invoice_paying_for_' + u.getUserId());