org.owasp.fileio.codecs.HTMLEntityCodec Maven / Gradle / Ivy
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The OWASP Java File I/O Security Project provides an easy to use library for validating and sanitizing filenames, directory paths, and uploaded files.
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/**
* This file is part of the Open Web Application Security Project (OWASP) Java File IO Security project. For details, please see
* https://www.owasp.org/index.php/OWASP_Java_File_I_O_Security_Project.
*
* Copyright (c) 2014 - The OWASP Foundation
*
* This API is published by OWASP under the Apache 2.0 license. You should read and accept the LICENSE before you use, modify, and/or redistribute this software.
*
* @author Jeff Williams Aspect Security - Original ESAPI author
* @author August Detlefsen CodeMagi - Java File IO Security Project lead
* @created 2014
*/
package org.owasp.fileio.codecs;
import java.util.HashMap;
import java.util.Collections;
import java.util.Map;
/**
* Implementation of the Codec interface for HTML entity encoding.
*/
public class HTMLEntityCodec extends Codec {
private static final char REPLACEMENT_CHAR = '\ufffd';
private static final String REPLACEMENT_HEX = "fffd";
private static final String REPLACEMENT_STR = "" + REPLACEMENT_CHAR;
private static final Map characterToEntityMap = mkCharacterToEntityMap();
private static final Trie entityToCharacterTrie = mkEntityToCharacterTrie();
/**
*
*/
public HTMLEntityCodec() {
}
/**
* {@inheritDoc}
*
* Encodes a Character for safe use in an HTML entity field.
*
* @param immune An array of characters that will not be encoded.
*/
@Override
public String encodeCharacter(char[] immune, Character c) {
// check for immune characters
if (containsCharacter(c, immune)) {
return "" + c;
}
// check for alphanumeric characters
String hex = Codec.getHexForNonAlphanumeric(c);
if (hex == null) {
return "" + c;
}
// check for illegal characters
if ((c <= 0x1f && c != '\t' && c != '\n' && c != '\r') || (c >= 0x7f && c <= 0x9f)) {
hex = REPLACEMENT_HEX; // Let's entity encode this instead of returning it
c = REPLACEMENT_CHAR;
}
// check if there's a defined entity
String entityName = (String) characterToEntityMap.get(c);
if (entityName != null) {
return "&" + entityName + ";";
}
// return the hex entity as suggested in the spec
return "&#x" + hex + ";";
}
/**
* {@inheritDoc}
*
* Returns the decoded version of the character starting at index, or null if no decoding is possible.
*
* Formats all are legal both with and without semi-colon, upper/lower case: &#dddd; &#xhhhh; &name;
*/
@Override
public Character decodeCharacter(PushbackString input) {
input.mark();
Character first = input.next();
if (first == null) {
input.reset();
return null;
}
// if this is not an encoded character, return null
if (first != '&') {
input.reset();
return null;
}
// test for numeric encodings
Character second = input.next();
if (second == null) {
input.reset();
return null;
}
if (second == '#') {
// handle numbers
Character c = getNumericEntity(input);
if (c != null) {
return c;
}
} else if (Character.isLetter(second.charValue())) {
// handle entities
input.pushback(second);
Character c = getNamedEntity(input);
if (c != null) {
return c;
}
}
input.reset();
return null;
}
/**
* getNumericEntry checks input to see if it is a numeric entity
*
* @param input The input to test for being a numeric entity
*
* @return null if input is null, the character of input after decoding
*/
private Character getNumericEntity(PushbackString input) {
Character first = input.peek();
if (first == null) {
return null;
}
if (first == 'x' || first == 'X') {
input.next();
return parseHex(input);
}
return parseNumber(input);
}
/**
* Parse a decimal number, such as those from JavaScript's String.fromCharCode(value)
*
* @param input decimal encoded string, such as 65
* @return character representation of this decimal value, e.g. A
* @throws NumberFormatException
*/
private Character parseNumber(PushbackString input) {
StringBuilder sb = new StringBuilder();
while (input.hasNext()) {
Character c = input.peek();
// if character is a digit then add it on and keep going
if (Character.isDigit(c.charValue())) {
sb.append(c);
input.next();
// if character is a semi-colon, eat it and quit
} else if (c == ';') {
input.next();
break;
// otherwise just quit
} else {
break;
}
}
try {
int i = Integer.parseInt(sb.toString());
if (Character.isValidCodePoint(i)) {
return (char) i;
}
} catch (NumberFormatException e) {
// throw an exception for malformed entity?
}
return null;
}
/**
* Parse a hex encoded entity
*
* @param input Hex encoded input (such as 437ae;)
* @return A single character from the string
* @throws NumberFormatException
*/
private Character parseHex(PushbackString input) {
StringBuilder sb = new StringBuilder();
while (input.hasNext()) {
Character c = input.peek();
// if character is a hex digit then add it on and keep going
if ("0123456789ABCDEFabcdef".indexOf(c) != -1) {
sb.append(c);
input.next();
// if character is a semi-colon, eat it and quit
} else if (c == ';') {
input.next();
break;
// otherwise just quit
} else {
break;
}
}
try {
int i = Integer.parseInt(sb.toString(), 16);
if (Character.isValidCodePoint(i)) {
return (char) i;
}
} catch (NumberFormatException e) {
// throw an exception for malformed entity?
}
return null;
}
/**
*
* Returns the decoded version of the character starting at index, or null if no decoding is possible.
*
* Formats all are legal both with and without semi-colon, upper/lower case: &aa; &aaa; &aaaa; &aaaaa; &aaaaaa; &aaaaaaa;
*
* @param input A string containing a named entity like "
* @return Returns the decoded version of the character starting at index, or null if no decoding is possible.
*/
private Character getNamedEntity(PushbackString input) {
StringBuilder possible = new StringBuilder();
Map.Entry entry;
int len;
// kludge around PushbackString....
len = Math.min(input.remainder().length(), entityToCharacterTrie.getMaxKeyLength());
for (int i = 0; i < len; i++) {
possible.append(Character.toLowerCase(input.next()));
}
// look up the longest match
entry = entityToCharacterTrie.getLongestMatch(possible);
if (entry == null) {
return null; // no match, caller will reset input
}
// fixup input
input.reset();
input.next(); // read &
len = entry.getKey().length(); // what matched's length
for (int i = 0; i < len; i++) {
input.next();
}
// check for a trailing semicolen
if (input.peek(';')) {
input.next();
}
return entry.getValue();
}
/**
* Build a unmodifiable Map from entity Character to Name.
*
* @return Unmodifiable map.
*/
private static synchronized Map mkCharacterToEntityMap() {
Map map = new HashMap(252);
map.put((char) 34, "quot"); /* quotation mark */
map.put((char) 38, "amp"); /* ampersand */
map.put((char) 60, "lt"); /* less-than sign */
map.put((char) 62, "gt"); /* greater-than sign */
map.put((char) 160, "nbsp"); /* no-break space */
map.put((char) 161, "iexcl"); /* inverted exclamation mark */
map.put((char) 162, "cent"); /* cent sign */
map.put((char) 163, "pound"); /* pound sign */
map.put((char) 164, "curren"); /* currency sign */
map.put((char) 165, "yen"); /* yen sign */
map.put((char) 166, "brvbar"); /* broken bar */
map.put((char) 167, "sect"); /* section sign */
map.put((char) 168, "uml"); /* diaeresis */
map.put((char) 169, "copy"); /* copyright sign */
map.put((char) 170, "ordf"); /* feminine ordinal indicator */
map.put((char) 171, "laquo"); /* left-pointing double angle quotation mark */
map.put((char) 172, "not"); /* not sign */
map.put((char) 173, "shy"); /* soft hyphen */
map.put((char) 174, "reg"); /* registered sign */
map.put((char) 175, "macr"); /* macron */
map.put((char) 176, "deg"); /* degree sign */
map.put((char) 177, "plusmn"); /* plus-minus sign */
map.put((char) 178, "sup2"); /* superscript two */
map.put((char) 179, "sup3"); /* superscript three */
map.put((char) 180, "acute"); /* acute accent */
map.put((char) 181, "micro"); /* micro sign */
map.put((char) 182, "para"); /* pilcrow sign */
map.put((char) 183, "middot"); /* middle dot */
map.put((char) 184, "cedil"); /* cedilla */
map.put((char) 185, "sup1"); /* superscript one */
map.put((char) 186, "ordm"); /* masculine ordinal indicator */
map.put((char) 187, "raquo"); /* right-pointing double angle quotation mark */
map.put((char) 188, "frac14"); /* vulgar fraction one quarter */
map.put((char) 189, "frac12"); /* vulgar fraction one half */
map.put((char) 190, "frac34"); /* vulgar fraction three quarters */
map.put((char) 191, "iquest"); /* inverted question mark */
map.put((char) 192, "Agrave"); /* Latin capital letter a with grave */
map.put((char) 193, "Aacute"); /* Latin capital letter a with acute */
map.put((char) 194, "Acirc"); /* Latin capital letter a with circumflex */
map.put((char) 195, "Atilde"); /* Latin capital letter a with tilde */
map.put((char) 196, "Auml"); /* Latin capital letter a with diaeresis */
map.put((char) 197, "Aring"); /* Latin capital letter a with ring above */
map.put((char) 198, "AElig"); /* Latin capital letter ae */
map.put((char) 199, "Ccedil"); /* Latin capital letter c with cedilla */
map.put((char) 200, "Egrave"); /* Latin capital letter e with grave */
map.put((char) 201, "Eacute"); /* Latin capital letter e with acute */
map.put((char) 202, "Ecirc"); /* Latin capital letter e with circumflex */
map.put((char) 203, "Euml"); /* Latin capital letter e with diaeresis */
map.put((char) 204, "Igrave"); /* Latin capital letter i with grave */
map.put((char) 205, "Iacute"); /* Latin capital letter i with acute */
map.put((char) 206, "Icirc"); /* Latin capital letter i with circumflex */
map.put((char) 207, "Iuml"); /* Latin capital letter i with diaeresis */
map.put((char) 208, "ETH"); /* Latin capital letter eth */
map.put((char) 209, "Ntilde"); /* Latin capital letter n with tilde */
map.put((char) 210, "Ograve"); /* Latin capital letter o with grave */
map.put((char) 211, "Oacute"); /* Latin capital letter o with acute */
map.put((char) 212, "Ocirc"); /* Latin capital letter o with circumflex */
map.put((char) 213, "Otilde"); /* Latin capital letter o with tilde */
map.put((char) 214, "Ouml"); /* Latin capital letter o with diaeresis */
map.put((char) 215, "times"); /* multiplication sign */
map.put((char) 216, "Oslash"); /* Latin capital letter o with stroke */
map.put((char) 217, "Ugrave"); /* Latin capital letter u with grave */
map.put((char) 218, "Uacute"); /* Latin capital letter u with acute */
map.put((char) 219, "Ucirc"); /* Latin capital letter u with circumflex */
map.put((char) 220, "Uuml"); /* Latin capital letter u with diaeresis */
map.put((char) 221, "Yacute"); /* Latin capital letter y with acute */
map.put((char) 222, "THORN"); /* Latin capital letter thorn */
map.put((char) 223, "szlig"); /* Latin small letter sharp sXCOMMAX German Eszett */
map.put((char) 224, "agrave"); /* Latin small letter a with grave */
map.put((char) 225, "aacute"); /* Latin small letter a with acute */
map.put((char) 226, "acirc"); /* Latin small letter a with circumflex */
map.put((char) 227, "atilde"); /* Latin small letter a with tilde */
map.put((char) 228, "auml"); /* Latin small letter a with diaeresis */
map.put((char) 229, "aring"); /* Latin small letter a with ring above */
map.put((char) 230, "aelig"); /* Latin lowercase ligature ae */
map.put((char) 231, "ccedil"); /* Latin small letter c with cedilla */
map.put((char) 232, "egrave"); /* Latin small letter e with grave */
map.put((char) 233, "eacute"); /* Latin small letter e with acute */
map.put((char) 234, "ecirc"); /* Latin small letter e with circumflex */
map.put((char) 235, "euml"); /* Latin small letter e with diaeresis */
map.put((char) 236, "igrave"); /* Latin small letter i with grave */
map.put((char) 237, "iacute"); /* Latin small letter i with acute */
map.put((char) 238, "icirc"); /* Latin small letter i with circumflex */
map.put((char) 239, "iuml"); /* Latin small letter i with diaeresis */
map.put((char) 240, "eth"); /* Latin small letter eth */
map.put((char) 241, "ntilde"); /* Latin small letter n with tilde */
map.put((char) 242, "ograve"); /* Latin small letter o with grave */
map.put((char) 243, "oacute"); /* Latin small letter o with acute */
map.put((char) 244, "ocirc"); /* Latin small letter o with circumflex */
map.put((char) 245, "otilde"); /* Latin small letter o with tilde */
map.put((char) 246, "ouml"); /* Latin small letter o with diaeresis */
map.put((char) 247, "divide"); /* division sign */
map.put((char) 248, "oslash"); /* Latin small letter o with stroke */
map.put((char) 249, "ugrave"); /* Latin small letter u with grave */
map.put((char) 250, "uacute"); /* Latin small letter u with acute */
map.put((char) 251, "ucirc"); /* Latin small letter u with circumflex */
map.put((char) 252, "uuml"); /* Latin small letter u with diaeresis */
map.put((char) 253, "yacute"); /* Latin small letter y with acute */
map.put((char) 254, "thorn"); /* Latin small letter thorn */
map.put((char) 255, "yuml"); /* Latin small letter y with diaeresis */
map.put((char) 338, "OElig"); /* Latin capital ligature oe */
map.put((char) 339, "oelig"); /* Latin small ligature oe */
map.put((char) 352, "Scaron"); /* Latin capital letter s with caron */
map.put((char) 353, "scaron"); /* Latin small letter s with caron */
map.put((char) 376, "Yuml"); /* Latin capital letter y with diaeresis */
map.put((char) 402, "fnof"); /* Latin small letter f with hook */
map.put((char) 710, "circ"); /* modifier letter circumflex accent */
map.put((char) 732, "tilde"); /* small tilde */
map.put((char) 913, "Alpha"); /* Greek capital letter alpha */
map.put((char) 914, "Beta"); /* Greek capital letter beta */
map.put((char) 915, "Gamma"); /* Greek capital letter gamma */
map.put((char) 916, "Delta"); /* Greek capital letter delta */
map.put((char) 917, "Epsilon"); /* Greek capital letter epsilon */
map.put((char) 918, "Zeta"); /* Greek capital letter zeta */
map.put((char) 919, "Eta"); /* Greek capital letter eta */
map.put((char) 920, "Theta"); /* Greek capital letter theta */
map.put((char) 921, "Iota"); /* Greek capital letter iota */
map.put((char) 922, "Kappa"); /* Greek capital letter kappa */
map.put((char) 923, "Lambda"); /* Greek capital letter lambda */
map.put((char) 924, "Mu"); /* Greek capital letter mu */
map.put((char) 925, "Nu"); /* Greek capital letter nu */
map.put((char) 926, "Xi"); /* Greek capital letter xi */
map.put((char) 927, "Omicron"); /* Greek capital letter omicron */
map.put((char) 928, "Pi"); /* Greek capital letter pi */
map.put((char) 929, "Rho"); /* Greek capital letter rho */
map.put((char) 931, "Sigma"); /* Greek capital letter sigma */
map.put((char) 932, "Tau"); /* Greek capital letter tau */
map.put((char) 933, "Upsilon"); /* Greek capital letter upsilon */
map.put((char) 934, "Phi"); /* Greek capital letter phi */
map.put((char) 935, "Chi"); /* Greek capital letter chi */
map.put((char) 936, "Psi"); /* Greek capital letter psi */
map.put((char) 937, "Omega"); /* Greek capital letter omega */
map.put((char) 945, "alpha"); /* Greek small letter alpha */
map.put((char) 946, "beta"); /* Greek small letter beta */
map.put((char) 947, "gamma"); /* Greek small letter gamma */
map.put((char) 948, "delta"); /* Greek small letter delta */
map.put((char) 949, "epsilon"); /* Greek small letter epsilon */
map.put((char) 950, "zeta"); /* Greek small letter zeta */
map.put((char) 951, "eta"); /* Greek small letter eta */
map.put((char) 952, "theta"); /* Greek small letter theta */
map.put((char) 953, "iota"); /* Greek small letter iota */
map.put((char) 954, "kappa"); /* Greek small letter kappa */
map.put((char) 955, "lambda"); /* Greek small letter lambda */
map.put((char) 956, "mu"); /* Greek small letter mu */
map.put((char) 957, "nu"); /* Greek small letter nu */
map.put((char) 958, "xi"); /* Greek small letter xi */
map.put((char) 959, "omicron"); /* Greek small letter omicron */
map.put((char) 960, "pi"); /* Greek small letter pi */
map.put((char) 961, "rho"); /* Greek small letter rho */
map.put((char) 962, "sigmaf"); /* Greek small letter final sigma */
map.put((char) 963, "sigma"); /* Greek small letter sigma */
map.put((char) 964, "tau"); /* Greek small letter tau */
map.put((char) 965, "upsilon"); /* Greek small letter upsilon */
map.put((char) 966, "phi"); /* Greek small letter phi */
map.put((char) 967, "chi"); /* Greek small letter chi */
map.put((char) 968, "psi"); /* Greek small letter psi */
map.put((char) 969, "omega"); /* Greek small letter omega */
map.put((char) 977, "thetasym"); /* Greek theta symbol */
map.put((char) 978, "upsih"); /* Greek upsilon with hook symbol */
map.put((char) 982, "piv"); /* Greek pi symbol */
map.put((char) 8194, "ensp"); /* en space */
map.put((char) 8195, "emsp"); /* em space */
map.put((char) 8201, "thinsp"); /* thin space */
map.put((char) 8204, "zwnj"); /* zero width non-joiner */
map.put((char) 8205, "zwj"); /* zero width joiner */
map.put((char) 8206, "lrm"); /* left-to-right mark */
map.put((char) 8207, "rlm"); /* right-to-left mark */
map.put((char) 8211, "ndash"); /* en dash */
map.put((char) 8212, "mdash"); /* em dash */
map.put((char) 8216, "lsquo"); /* left single quotation mark */
map.put((char) 8217, "rsquo"); /* right single quotation mark */
map.put((char) 8218, "sbquo"); /* single low-9 quotation mark */
map.put((char) 8220, "ldquo"); /* left double quotation mark */
map.put((char) 8221, "rdquo"); /* right double quotation mark */
map.put((char) 8222, "bdquo"); /* double low-9 quotation mark */
map.put((char) 8224, "dagger"); /* dagger */
map.put((char) 8225, "Dagger"); /* double dagger */
map.put((char) 8226, "bull"); /* bullet */
map.put((char) 8230, "hellip"); /* horizontal ellipsis */
map.put((char) 8240, "permil"); /* per mille sign */
map.put((char) 8242, "prime"); /* prime */
map.put((char) 8243, "Prime"); /* double prime */
map.put((char) 8249, "lsaquo"); /* single left-pointing angle quotation mark */
map.put((char) 8250, "rsaquo"); /* single right-pointing angle quotation mark */
map.put((char) 8254, "oline"); /* overline */
map.put((char) 8260, "frasl"); /* fraction slash */
map.put((char) 8364, "euro"); /* euro sign */
map.put((char) 8465, "image"); /* black-letter capital i */
map.put((char) 8472, "weierp"); /* script capital pXCOMMAX Weierstrass p */
map.put((char) 8476, "real"); /* black-letter capital r */
map.put((char) 8482, "trade"); /* trademark sign */
map.put((char) 8501, "alefsym"); /* alef symbol */
map.put((char) 8592, "larr"); /* leftwards arrow */
map.put((char) 8593, "uarr"); /* upwards arrow */
map.put((char) 8594, "rarr"); /* rightwards arrow */
map.put((char) 8595, "darr"); /* downwards arrow */
map.put((char) 8596, "harr"); /* left right arrow */
map.put((char) 8629, "crarr"); /* downwards arrow with corner leftwards */
map.put((char) 8656, "lArr"); /* leftwards double arrow */
map.put((char) 8657, "uArr"); /* upwards double arrow */
map.put((char) 8658, "rArr"); /* rightwards double arrow */
map.put((char) 8659, "dArr"); /* downwards double arrow */
map.put((char) 8660, "hArr"); /* left right double arrow */
map.put((char) 8704, "forall"); /* for all */
map.put((char) 8706, "part"); /* partial differential */
map.put((char) 8707, "exist"); /* there exists */
map.put((char) 8709, "empty"); /* empty set */
map.put((char) 8711, "nabla"); /* nabla */
map.put((char) 8712, "isin"); /* element of */
map.put((char) 8713, "notin"); /* not an element of */
map.put((char) 8715, "ni"); /* contains as member */
map.put((char) 8719, "prod"); /* n-ary product */
map.put((char) 8721, "sum"); /* n-ary summation */
map.put((char) 8722, "minus"); /* minus sign */
map.put((char) 8727, "lowast"); /* asterisk operator */
map.put((char) 8730, "radic"); /* square root */
map.put((char) 8733, "prop"); /* proportional to */
map.put((char) 8734, "infin"); /* infinity */
map.put((char) 8736, "ang"); /* angle */
map.put((char) 8743, "and"); /* logical and */
map.put((char) 8744, "or"); /* logical or */
map.put((char) 8745, "cap"); /* intersection */
map.put((char) 8746, "cup"); /* union */
map.put((char) 8747, "int"); /* integral */
map.put((char) 8756, "there4"); /* therefore */
map.put((char) 8764, "sim"); /* tilde operator */
map.put((char) 8773, "cong"); /* congruent to */
map.put((char) 8776, "asymp"); /* almost equal to */
map.put((char) 8800, "ne"); /* not equal to */
map.put((char) 8801, "equiv"); /* identical toXCOMMAX equivalent to */
map.put((char) 8804, "le"); /* less-than or equal to */
map.put((char) 8805, "ge"); /* greater-than or equal to */
map.put((char) 8834, "sub"); /* subset of */
map.put((char) 8835, "sup"); /* superset of */
map.put((char) 8836, "nsub"); /* not a subset of */
map.put((char) 8838, "sube"); /* subset of or equal to */
map.put((char) 8839, "supe"); /* superset of or equal to */
map.put((char) 8853, "oplus"); /* circled plus */
map.put((char) 8855, "otimes"); /* circled times */
map.put((char) 8869, "perp"); /* up tack */
map.put((char) 8901, "sdot"); /* dot operator */
map.put((char) 8968, "lceil"); /* left ceiling */
map.put((char) 8969, "rceil"); /* right ceiling */
map.put((char) 8970, "lfloor"); /* left floor */
map.put((char) 8971, "rfloor"); /* right floor */
map.put((char) 9001, "lang"); /* left-pointing angle bracket */
map.put((char) 9002, "rang"); /* right-pointing angle bracket */
map.put((char) 9674, "loz"); /* lozenge */
map.put((char) 9824, "spades"); /* black spade suit */
map.put((char) 9827, "clubs"); /* black club suit */
map.put((char) 9829, "hearts"); /* black heart suit */
map.put((char) 9830, "diams"); /* black diamond suit */
return Collections.unmodifiableMap(map);
}
/**
* Build a unmodifiable Trie from entitiy Name to Character
*
* @return Unmodifiable trie.
*/
private static synchronized Trie mkEntityToCharacterTrie() {
Trie trie = new HashTrie();
for (Map.Entry entry : characterToEntityMap.entrySet()) {
trie.put(entry.getValue(), entry.getKey());
}
return Trie.Util.unmodifiable(trie);
}
}