MDEV-20110 don't try to load client plugins with invalid names

reported by lixtelnis

2 files changed, 16 insertions, 0 deletions

diff --git a/mysql-test/r/connect_debug.result b/mysql-test/r/connect_debug.result
index 0452b238db9..3151166a0e6 100644
--- a/mysql-test/r/connect_debug.result
+++ b/mysql-test/r/connect_debug.result
@@ -3,3 +3,8 @@ set global debug_dbug='+d,auth_disconnect';
 create user 'bad' identified by 'worse';
 set global debug_dbug=@old_dbug;
 drop user bad;
+set global debug_dbug='+d,auth_invalid_plugin';
+create user 'bad' identified by 'worse';
+ERROR 2059 (HY000): Authentication plugin 'foo/bar' cannot be loaded: invalid plugin name
+set global debug_dbug=@old_dbug;
+drop user bad;
diff --git a/mysql-test/t/connect_debug.test b/mysql-test/t/connect_debug.test
index 299b605b2cd..7a2f2872b79 100644
--- a/mysql-test/t/connect_debug.test
+++ b/mysql-test/t/connect_debug.test
@@ -1,3 +1,4 @@
+source include/not_embedded.inc;
 source include/have_debug.inc;
 set @old_dbug=@@global.debug_dbug;
 
@@ -10,3 +11,13 @@ create user 'bad' identified by 'worse';
 --exec $MYSQL --default-auth=mysql_old_password --user=bad --password=worse
 set global debug_dbug=@old_dbug;
 drop user bad;
+
+#
+# malicious server, invalid plugin name
+#
+set global debug_dbug='+d,auth_invalid_plugin';
+create user 'bad' identified by 'worse';
+--error 1
+--exec $MYSQL --default-auth=mysql_old_password --user=bad --password=worse 2>&1
+set global debug_dbug=@old_dbug;
+drop user bad;