/*
* Copyright 2005-2010 the original author or authors.
*
* 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 org.springframework.security.ldap.authentication;
import org.springframework.ldap.BadLdapGrammarException;
/**
* Helper class to encode and decode ldap names and values.
*
* <p>
* NOTE: This is a copy from Spring LDAP so that both Spring LDAP 1.x and 2.x
* can be supported without reflection.
* </p>
*
* @author Adam Skogman
* @author Mattias Hellborg Arthursson
*/
final class LdapEncoder {
private static final int HEX = 16;
private static String[] NAME_ESCAPE_TABLE = new String[96];
private static String[] FILTER_ESCAPE_TABLE = new String['\\' + 1];
static {
// Name encoding table -------------------------------------
// all below 0x20 (control chars)
for (char c = 0; c < ' '; c++) {
NAME_ESCAPE_TABLE[c] = "\\" + toTwoCharHex(c);
}
NAME_ESCAPE_TABLE['#'] = "\\#";
NAME_ESCAPE_TABLE[','] = "\\,";
NAME_ESCAPE_TABLE[';'] = "\\;";
NAME_ESCAPE_TABLE['='] = "\\=";
NAME_ESCAPE_TABLE['+'] = "\\+";
NAME_ESCAPE_TABLE['<'] = "\\<";
NAME_ESCAPE_TABLE['>'] = "\\>";
NAME_ESCAPE_TABLE['\"'] = "\\\"";
NAME_ESCAPE_TABLE['\\'] = "\\\\";
// Filter encoding table -------------------------------------
// fill with char itself
for (char c = 0; c < FILTER_ESCAPE_TABLE.length; c++) {
FILTER_ESCAPE_TABLE[c] = String.valueOf(c);
}
// escapes (RFC2254)
FILTER_ESCAPE_TABLE['*'] = "\\2a";
FILTER_ESCAPE_TABLE['('] = "\\28";
FILTER_ESCAPE_TABLE[')'] = "\\29";
FILTER_ESCAPE_TABLE['\\'] = "\\5c";
FILTER_ESCAPE_TABLE[0] = "\\00";
}
/**
* All static methods - not to be instantiated.
*/
private LdapEncoder() {
}
protected static String toTwoCharHex(char c) {
String raw = Integer.toHexString(c).toUpperCase();
if (raw.length() > 1) {
return raw;
} else {
return "0" + raw;
}
}
/**
* Escape a value for use in a filter.
*
* @param value
* the value to escape.
* @return a properly escaped representation of the supplied value.
*/
public static String filterEncode(String value) {
if (value == null)
return null;
// make buffer roomy
StringBuilder encodedValue = new StringBuilder(value.length() * 2);
int length = value.length();
for (int i = 0; i < length; i++) {
char c = value.charAt(i);
if (c < FILTER_ESCAPE_TABLE.length) {
encodedValue.append(FILTER_ESCAPE_TABLE[c]);
} else {
// default: add the char
encodedValue.append(c);
}
}
return encodedValue.toString();
}
/**
* LDAP Encodes a value for use with a DN. Escapes for LDAP, not JNDI!
*
* <br/>Escapes:<br/> ' ' [space] - "\ " [if first or last] <br/> '#'
* [hash] - "\#" <br/> ',' [comma] - "\," <br/> ';' [semicolon] - "\;" <br/> '=
* [equals] - "\=" <br/> '+' [plus] - "\+" <br/> '<' [less than] -
* "\<" <br/> '>' [greater than] - "\>" <br/> '"' [double quote] -
* "\"" <br/> '\' [backslash] - "\\" <br/>
*
* @param value
* the value to escape.
* @return The escaped value.
*/
public static String nameEncode(String value) {
if (value == null)
return null;
// make buffer roomy
StringBuilder encodedValue = new StringBuilder(value.length() * 2);
int length = value.length();
int last = length - 1;
for (int i = 0; i < length; i++) {
char c = value.charAt(i);
// space first or last
if (c == ' ' && (i == 0 || i == last)) {
encodedValue.append("\\ ");
continue;
}
if (c < NAME_ESCAPE_TABLE.length) {
// check in table for escapes
String esc = NAME_ESCAPE_TABLE[c];
if (esc != null) {
encodedValue.append(esc);
continue;
}
}
// default: add the char
encodedValue.append(c);
}
return encodedValue.toString();
}
/**
* Decodes a value. Converts escaped chars to ordinary chars.
*
* @param value
* Trimmed value, so no leading an trailing blanks, except an
* escaped space last.
* @return The decoded value as a string.
* @throws BadLdapGrammarException
*/
static public String nameDecode(String value)
throws BadLdapGrammarException {
if (value == null)
return null;
// make buffer same size
StringBuilder decoded = new StringBuilder(value.length());
int i = 0;
while (i < value.length()) {
char currentChar = value.charAt(i);
if (currentChar == '\\') {
if (value.length() <= i + 1) {
// Ending with a single backslash is not allowed
throw new BadLdapGrammarException(
"Unexpected end of value " + "unterminated '\\'");
} else {
char nextChar = value.charAt(i + 1);
if (nextChar == ',' || nextChar == '=' || nextChar == '+'
|| nextChar == '<' || nextChar == '>'
|| nextChar == '#' || nextChar == ';'
|| nextChar == '\\' || nextChar == '\"'
|| nextChar == ' ') {
// Normal backslash escape
decoded.append(nextChar);
i += 2;
} else {
if (value.length() <= i + 2) {
throw new BadLdapGrammarException(
"Unexpected end of value "
+ "expected special or hex, found '"
+ nextChar + "'");
} else {
// This should be a hex value
String hexString = "" + nextChar
+ value.charAt(i + 2);
decoded.append((char) Integer.parseInt(hexString,
HEX));
i += 3;
}
}
}
} else {
// This character wasn't escaped - just append it
decoded.append(currentChar);
i++;
}
}
return decoded.toString();
}
}