From aed855e6920923898b94a1b922fbace27a34ddf2 Mon Sep 17 00:00:00 2001
From: Petri Lehtinen <petri@digip.org>
Date: Mon, 9 Jul 2018 22:26:35 +0300
Subject: [PATCH] Avoid invalid memory read in json_pack()

Initial patch by @bharjoc-bitdefender

Fixes #421
---
 src/pack_unpack.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/pack_unpack.c b/src/pack_unpack.c
index 6461c06..b842772 100644
--- a/src/pack_unpack.c
+++ b/src/pack_unpack.c
@@ -75,6 +75,9 @@ static void next_token(scanner_t *s)
         return;
     }
 
+    if (!token(s) && !*s->fmt)
+        return;
+
     t = s->fmt;
     s->column++;
     s->pos++;
@@ -97,7 +100,7 @@ static void next_token(scanner_t *s)
     s->token.column = s->column;
     s->token.pos = s->pos;
 
-    t++;
+    if (*t) t++;
     s->fmt = t;
 }