com.h3xstream.findsecbugs.RegexRedosAnalyzer Maven / Gradle / Ivy
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Core module of the project. It include all the SpotBugs detectors.
The resulting jar is the published plugin.
The newest version!
/**
* Find Security Bugs
* Copyright (c) Philippe Arteau, All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3.0 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library.
*/
package com.h3xstream.findsecbugs;
public class RegexRedosAnalyzer {
private static final char[] OPENING_CHAR = {'(', '['};
private static final char[] CLOSING_CHAR = {')', ']'};
private static final char[] PLUS_CHAR = {'+', '*', '?'};
private boolean vulnerable = false;
public boolean isVulnerable() {
return vulnerable;
}
public void analyseRegexString(String regex) {
if (regex.length() > 0) {
recurAnalyseRegex(regex, regex.length() - 1, 0);
}
}
private int recurAnalyseRegex(String regex, int startPosition, int level) {
// print(level, "level = " + level);
if (level == 2) {
vulnerable = true;
return 0;
}
// print(level, "Analysing " + regex.substring(0, startPosition + 1));
boolean openingMode = false;
for (int i = startPosition; i >= 0; i--) {
// print(level, "[" + i + "] = '" + regex.charAt(i) + "'");
if (isChar(regex, i, OPENING_CHAR)) {
// print(level, "<<<<");
return i;
}
if (isChar(regex, i, CLOSING_CHAR)) {
int newLevel = level;
if (i + 1 < regex.length() && isChar(regex, i + 1, PLUS_CHAR)) {
newLevel += 1;
}
// print(level, ">>>>");
openingMode = true;
i = recurAnalyseRegex(regex, i - 1, newLevel);
if (i == -1) {
return 0;
}
// print(level, "Restarting at " + i);
}
}
// print(level, "END!");
return 0;
}
/**
* @param value
* @param position
* @param charToTest
* @return
*/
private boolean isChar(String value, int position, char[] charToTest) {
char actualChar = value.charAt(position);
boolean oneCharFound = false;
for (char ch : charToTest) {
if (actualChar == ch) {
oneCharFound = true;
break;
}
}
return oneCharFound && (position == 0 || value.charAt(position - 1) != '\\');
}
//Debug method
// private void print(int level,Object obj) {
// System.out.println(lvl(level) + "> "+ obj);
// }
//
// private String lvl(int level) {
// StringBuilder str = new StringBuilder();
// for(int i=0;i