Fix for Bug#29605

--local-infile=0 checks can be bypassed by sending a FETCH LOCAL FILE response
  
Add a check for CLIENT_LOCAL_FILES before sending a local file.
Beware, that all binary distributions enable sending of local files and it's up
to the programs which use libmysql to disable it, if they don't use this functionality.
Otherwise they are not safe.

client/mysqltest.c

@@ -6333,6 +6333,8 @@ int util_query(MYSQL* org_mysql, const char* query){
     if (!(mysql= mysql_init(mysql)))
       die("Failed in mysql_init()");
 
+    /* enable local infile, in non-binary builds often disabled by default */
+    mysql_options(mysql, MYSQL_OPT_LOCAL_INFILE, 0);
     safe_connect(mysql, "util", org_mysql->host, org_mysql->user,
                  org_mysql->passwd, org_mysql->db, org_mysql->port,
                  org_mysql->unix_socket);

sql-common/client.c

@@ -2736,7 +2736,15 @@ static my_bool cli_read_query_result(MYSQL *mysql)
 #ifdef MYSQL_CLIENT
   if (field_count == NULL_LENGTH)		/* LOAD DATA LOCAL INFILE */
   {
-    int error=handle_local_infile(mysql,(char*) pos);
+    int error;
+
+    if (!(mysql->options.client_flag & CLIENT_LOCAL_FILES))
+    {
+      set_mysql_error(mysql, CR_MALFORMED_PACKET, unknown_sqlstate);
+      DBUG_RETURN(1);
+    }   
+
+    error= handle_local_infile(mysql,(char*) pos);
     if ((length= cli_safe_read(mysql)) == packet_error || error)
       DBUG_RETURN(1);
     goto get_info;				/* Get info packet */

tests/mysql_client_test.c

@@ -289,6 +289,8 @@ static void client_connect(ulong flag)
     myerror("mysql_init() failed");
     exit(1);
   }
+  /* enable local infile, in non-binary builds often disabled by default */
+  mysql_options(mysql, MYSQL_OPT_LOCAL_INFILE, 0);
 
   if (!(mysql_real_connect(mysql, opt_host, opt_user,
                            opt_password, opt_db ? opt_db:"test", opt_port,