From fd9f3f13a3d99aa828ed9cd0625d87a9991dd486 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Javier=20Jaramago=20Fern=C3=A1ndez?=
 <jaramago.fernandez.javier@gmail.com>
Date: Thu, 19 Aug 2021 21:40:54 +0200
Subject: [PATCH] Fixed 'strcat-param-overlap' found by ASAN in
 'IsKeepMultiplexEnabledVariables' #3554

---
 lib/mysql_connection.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/mysql_connection.cpp b/lib/mysql_connection.cpp
index e1d6352af..699cc0d75 100644
--- a/lib/mysql_connection.cpp
+++ b/lib/mysql_connection.cpp
@@ -2254,7 +2254,11 @@ bool MySQL_Connection::IsKeepMultiplexEnabledVariables(char *query_digest_text)
 	}
 	while (query_digest_text_filter_select && (match = strcasestr(query_digest_text_filter_select,"@@"))) {
 		*match = '\0';
-		strcat(query_digest_text_filter_select, match+strlen("@@"));
+		if (strlen(query_digest_text_filter_select) == 0) {
+			memcpy(query_digest_text_filter_select, match, strlen("@@"));
+		} else {
+			strcat(query_digest_text_filter_select, match+strlen("@@"));
+		}
 	}
 
 	std::vector<char*>query_digest_text_filter_select_v;