From 2a05fa0d481d12d3747465c4f14470bdca100c5d Mon Sep 17 00:00:00 2001
From: hwware <wen.hui.ware@gmail.com>
Date: Mon, 8 Jun 2020 23:36:01 -0400
Subject: [PATCH] fix server crash in STRALGO command

---
 src/t_string.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/t_string.c b/src/t_string.c
index 5306069bf..d1a3e1b96 100644
--- a/src/t_string.c
+++ b/src/t_string.c
@@ -534,6 +534,13 @@ void stralgoLCS(client *c) {
             }
             obja = lookupKeyRead(c->db,c->argv[j+1]);
             objb = lookupKeyRead(c->db,c->argv[j+2]);
+
+            if ( !(obja->type == OBJ_STRING) || !(objb->type == OBJ_STRING) ) {
+                addReplyError(c,"Object associate with KEYS option should only be string type");
+                return;
+
+            }
+
             obja = obja ? getDecodedObject(obja) : createStringObject("",0);
             objb = objb ? getDecodedObject(objb) : createStringObject("",0);
             a = obja->ptr;