com.wavemaker.commons.util.FileValidationUtils Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (C) 2022-2023 WaveMaker, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
******************************************************************************/
package com.wavemaker.commons.util;
import com.wavemaker.commons.WMRuntimeException;
/*
* This class is used to validate File Paths having /.., ../, ./ etc which are directory traversal elements
* by which attacker can gain access to parent directory.
* */
public class FileValidationUtils {
public static String validateFilePath(String path) {
if (path != null) {
for (int i = path.length(); i > 0; ) {
int slashIndex = path.lastIndexOf('/', i - 1);
int gap = i - slashIndex;
if (gap == 2 && path.charAt(slashIndex + 1) == '.') {
throw new WMRuntimeException("Path contains Directory Traversal elements");
}
if (gap == 3 && path.charAt(slashIndex + 1) == '.' && path.charAt(slashIndex + 2) == '.') {
throw new WMRuntimeException("Path contains Directory Traversal elements");
}
i = slashIndex;
}
}
return path;
}
}