| | |
| | | * |
| | | * @author ruoyi |
| | | */ |
| | | public final class HTMLFilter |
| | | { |
| | | public final class HTMLFilter { |
| | | /** |
| | | * regex flag union representing /si modifiers in php |
| | | **/ |
| | |
| | | /** |
| | | * Default constructor. |
| | | */ |
| | | public HTMLFilter() |
| | | { |
| | | public HTMLFilter() { |
| | | vAllowed = new HashMap<>(); |
| | | |
| | | final ArrayList<String> a_atts = new ArrayList<>(); |
| | |
| | | vAllowed.put("i", no_atts); |
| | | vAllowed.put("em", no_atts); |
| | | |
| | | vSelfClosingTags = new String[] { "img" }; |
| | | vNeedClosingTags = new String[] { "a", "b", "strong", "i", "em" }; |
| | | vSelfClosingTags = new String[] {"img"}; |
| | | vNeedClosingTags = new String[] {"a", "b", "strong", "i", "em"}; |
| | | vDisallowed = new String[] {}; |
| | | vAllowedProtocols = new String[] { "http", "mailto", "https" }; // no ftp. |
| | | vProtocolAtts = new String[] { "src", "href" }; |
| | | vRemoveBlanks = new String[] { "a", "b", "strong", "i", "em" }; |
| | | vAllowedEntities = new String[] { "amp", "gt", "lt", "quot" }; |
| | | vAllowedProtocols = new String[] {"http", "mailto", "https"}; // no ftp. |
| | | vProtocolAtts = new String[] {"src", "href"}; |
| | | vRemoveBlanks = new String[] {"a", "b", "strong", "i", "em"}; |
| | | vAllowedEntities = new String[] {"amp", "gt", "lt", "quot"}; |
| | | stripComment = true; |
| | | encodeQuotes = true; |
| | | alwaysMakeTags = false; |
| | |
| | | /** |
| | | * Map-parameter configurable constructor. |
| | | * |
| | | * @param conf map containing configuration. keys match field names. |
| | | * @param conf |
| | | * map containing configuration. keys match field names. |
| | | */ |
| | | @SuppressWarnings("unchecked") |
| | | public HTMLFilter(final Map<String, Object> conf) |
| | | { |
| | | public HTMLFilter(final Map<String, Object> conf) { |
| | | |
| | | assert conf.containsKey("vAllowed") : "configuration requires vAllowed"; |
| | | assert conf.containsKey("vSelfClosingTags") : "configuration requires vSelfClosingTags"; |
| | |
| | | assert conf.containsKey("vRemoveBlanks") : "configuration requires vRemoveBlanks"; |
| | | assert conf.containsKey("vAllowedEntities") : "configuration requires vAllowedEntities"; |
| | | |
| | | vAllowed = Collections.unmodifiableMap((HashMap<String, List<String>>) conf.get("vAllowed")); |
| | | vSelfClosingTags = (String[]) conf.get("vSelfClosingTags"); |
| | | vNeedClosingTags = (String[]) conf.get("vNeedClosingTags"); |
| | | vDisallowed = (String[]) conf.get("vDisallowed"); |
| | | vAllowedProtocols = (String[]) conf.get("vAllowedProtocols"); |
| | | vProtocolAtts = (String[]) conf.get("vProtocolAtts"); |
| | | vRemoveBlanks = (String[]) conf.get("vRemoveBlanks"); |
| | | vAllowedEntities = (String[]) conf.get("vAllowedEntities"); |
| | | stripComment = conf.containsKey("stripComment") ? (Boolean) conf.get("stripComment") : true; |
| | | encodeQuotes = conf.containsKey("encodeQuotes") ? (Boolean) conf.get("encodeQuotes") : true; |
| | | alwaysMakeTags = conf.containsKey("alwaysMakeTags") ? (Boolean) conf.get("alwaysMakeTags") : true; |
| | | } |
| | | |
| | | private void reset() |
| | | { |
| | | vTagCounts.clear(); |
| | | vAllowed = Collections.unmodifiableMap((HashMap<String, List<String>>)conf.get("vAllowed")); |
| | | vSelfClosingTags = (String[])conf.get("vSelfClosingTags"); |
| | | vNeedClosingTags = (String[])conf.get("vNeedClosingTags"); |
| | | vDisallowed = (String[])conf.get("vDisallowed"); |
| | | vAllowedProtocols = (String[])conf.get("vAllowedProtocols"); |
| | | vProtocolAtts = (String[])conf.get("vProtocolAtts"); |
| | | vRemoveBlanks = (String[])conf.get("vRemoveBlanks"); |
| | | vAllowedEntities = (String[])conf.get("vAllowedEntities"); |
| | | stripComment = conf.containsKey("stripComment") ? (Boolean)conf.get("stripComment") : true; |
| | | encodeQuotes = conf.containsKey("encodeQuotes") ? (Boolean)conf.get("encodeQuotes") : true; |
| | | alwaysMakeTags = conf.containsKey("alwaysMakeTags") ? (Boolean)conf.get("alwaysMakeTags") : true; |
| | | } |
| | | |
| | | // --------------------------------------------------------------- |
| | | // my versions of some PHP library functions |
| | | public static String chr(final int decimal) |
| | | { |
| | | return String.valueOf((char) decimal); |
| | | public static String chr(final int decimal) { |
| | | return String.valueOf((char)decimal); |
| | | } |
| | | |
| | | public static String htmlSpecialChars(final String s) |
| | | { |
| | | public static String htmlSpecialChars(final String s) { |
| | | String result = s; |
| | | result = regexReplace(P_AMP, "&", result); |
| | | result = regexReplace(P_QUOTE, """, result); |
| | |
| | | return result; |
| | | } |
| | | |
| | | private static String regexReplace(final Pattern regex_pattern, final String replacement, final String s) { |
| | | Matcher m = regex_pattern.matcher(s); |
| | | return m.replaceAll(replacement); |
| | | } |
| | | |
| | | // --------------------------------------------------------------- |
| | | |
| | | private static boolean inArray(final String s, final String[] array) { |
| | | for (String item : array) { |
| | | if (item != null && item.equals(s)) { |
| | | return true; |
| | | } |
| | | } |
| | | return false; |
| | | } |
| | | |
| | | private void reset() { |
| | | vTagCounts.clear(); |
| | | } |
| | | |
| | | /** |
| | | * given a user submitted input String, filter out any invalid or restricted html. |
| | | * |
| | | * @param input text (i.e. submitted by a user) than may contain html |
| | | * @param input |
| | | * text (i.e. submitted by a user) than may contain html |
| | | * @return "clean" version of input, with only valid, whitelisted html elements allowed |
| | | */ |
| | | public String filter(final String input) |
| | | { |
| | | public String filter(final String input) { |
| | | reset(); |
| | | String s = input; |
| | | |
| | |
| | | return s; |
| | | } |
| | | |
| | | public boolean isAlwaysMakeTags() |
| | | { |
| | | public boolean isAlwaysMakeTags() { |
| | | return alwaysMakeTags; |
| | | } |
| | | |
| | | public boolean isStripComments() |
| | | { |
| | | public boolean isStripComments() { |
| | | return stripComment; |
| | | } |
| | | |
| | | private String escapeComments(final String s) |
| | | { |
| | | private String escapeComments(final String s) { |
| | | final Matcher m = P_COMMENTS.matcher(s); |
| | | final StringBuffer buf = new StringBuffer(); |
| | | if (m.find()) |
| | | { |
| | | if (m.find()) { |
| | | final String match = m.group(1); // (.*?) |
| | | m.appendReplacement(buf, Matcher.quoteReplacement("<!--" + htmlSpecialChars(match) + "-->")); |
| | | } |
| | |
| | | return buf.toString(); |
| | | } |
| | | |
| | | private String balanceHTML(String s) |
| | | { |
| | | if (alwaysMakeTags) |
| | | { |
| | | private String balanceHTML(String s) { |
| | | if (alwaysMakeTags) { |
| | | // |
| | | // try and form html |
| | | // |
| | |
| | | s = regexReplace(P_BODY_TO_END, "<$1>", s); |
| | | s = regexReplace(P_XML_CONTENT, "$1<$2", s); |
| | | |
| | | } |
| | | else |
| | | { |
| | | } else { |
| | | // |
| | | // escape stray brackets |
| | | // |
| | |
| | | return s; |
| | | } |
| | | |
| | | private String checkTags(String s) |
| | | { |
| | | private String checkTags(String s) { |
| | | Matcher m = P_TAGS.matcher(s); |
| | | |
| | | final StringBuffer buf = new StringBuffer(); |
| | | while (m.find()) |
| | | { |
| | | while (m.find()) { |
| | | String replaceStr = m.group(1); |
| | | replaceStr = processTag(replaceStr); |
| | | m.appendReplacement(buf, Matcher.quoteReplacement(replaceStr)); |
| | |
| | | // these get tallied in processTag |
| | | // (remember to reset before subsequent calls to filter method) |
| | | final StringBuilder sBuilder = new StringBuilder(buf.toString()); |
| | | for (String key : vTagCounts.keySet()) |
| | | { |
| | | for (int ii = 0; ii < vTagCounts.get(key); ii++) |
| | | { |
| | | for (String key : vTagCounts.keySet()) { |
| | | for (int ii = 0; ii < vTagCounts.get(key); ii++) { |
| | | sBuilder.append("</").append(key).append(">"); |
| | | } |
| | | } |
| | |
| | | return s; |
| | | } |
| | | |
| | | private String processRemoveBlanks(final String s) |
| | | { |
| | | private String processRemoveBlanks(final String s) { |
| | | String result = s; |
| | | for (String tag : vRemoveBlanks) |
| | | { |
| | | if (!P_REMOVE_PAIR_BLANKS.containsKey(tag)) |
| | | { |
| | | for (String tag : vRemoveBlanks) { |
| | | if (!P_REMOVE_PAIR_BLANKS.containsKey(tag)) { |
| | | P_REMOVE_PAIR_BLANKS.putIfAbsent(tag, Pattern.compile("<" + tag + "(\\s[^>]*)?></" + tag + ">")); |
| | | } |
| | | result = regexReplace(P_REMOVE_PAIR_BLANKS.get(tag), "", result); |
| | | if (!P_REMOVE_SELF_BLANKS.containsKey(tag)) |
| | | { |
| | | if (!P_REMOVE_SELF_BLANKS.containsKey(tag)) { |
| | | P_REMOVE_SELF_BLANKS.putIfAbsent(tag, Pattern.compile("<" + tag + "(\\s[^>]*)?/>")); |
| | | } |
| | | result = regexReplace(P_REMOVE_SELF_BLANKS.get(tag), "", result); |
| | |
| | | return result; |
| | | } |
| | | |
| | | private static String regexReplace(final Pattern regex_pattern, final String replacement, final String s) |
| | | { |
| | | Matcher m = regex_pattern.matcher(s); |
| | | return m.replaceAll(replacement); |
| | | } |
| | | |
| | | private String processTag(final String s) |
| | | { |
| | | private String processTag(final String s) { |
| | | // ending tags |
| | | Matcher m = P_END_TAG.matcher(s); |
| | | if (m.find()) |
| | | { |
| | | if (m.find()) { |
| | | final String name = m.group(1).toLowerCase(); |
| | | if (allowed(name)) |
| | | { |
| | | if (false == inArray(name, vSelfClosingTags)) |
| | | { |
| | | if (vTagCounts.containsKey(name)) |
| | | { |
| | | if (allowed(name)) { |
| | | if (false == inArray(name, vSelfClosingTags)) { |
| | | if (vTagCounts.containsKey(name)) { |
| | | vTagCounts.put(name, vTagCounts.get(name) - 1); |
| | | return "</" + name + ">"; |
| | | } |
| | |
| | | |
| | | // starting tags |
| | | m = P_START_TAG.matcher(s); |
| | | if (m.find()) |
| | | { |
| | | if (m.find()) { |
| | | final String name = m.group(1).toLowerCase(); |
| | | final String body = m.group(2); |
| | | String ending = m.group(3); |
| | | |
| | | // debug( "in a starting tag, name='" + name + "'; body='" + body + "'; ending='" + ending + "'" ); |
| | | if (allowed(name)) |
| | | { |
| | | if (allowed(name)) { |
| | | final StringBuilder params = new StringBuilder(); |
| | | |
| | | final Matcher m2 = P_QUOTED_ATTRIBUTES.matcher(body); |
| | | final Matcher m3 = P_UNQUOTED_ATTRIBUTES.matcher(body); |
| | | final List<String> paramNames = new ArrayList<>(); |
| | | final List<String> paramValues = new ArrayList<>(); |
| | | while (m2.find()) |
| | | { |
| | | while (m2.find()) { |
| | | paramNames.add(m2.group(1)); // ([a-z0-9]+) |
| | | paramValues.add(m2.group(3)); // (.*?) |
| | | } |
| | | while (m3.find()) |
| | | { |
| | | while (m3.find()) { |
| | | paramNames.add(m3.group(1)); // ([a-z0-9]+) |
| | | paramValues.add(m3.group(3)); // ([^\"\\s']+) |
| | | } |
| | | |
| | | String paramName, paramValue; |
| | | for (int ii = 0; ii < paramNames.size(); ii++) |
| | | { |
| | | for (int ii = 0; ii < paramNames.size(); ii++) { |
| | | paramName = paramNames.get(ii).toLowerCase(); |
| | | paramValue = paramValues.get(ii); |
| | | |
| | |
| | | // debug( "paramValue='" + paramValue + "'" ); |
| | | // debug( "allowed? " + vAllowed.get( name ).contains( paramName ) ); |
| | | |
| | | if (allowedAttribute(name, paramName)) |
| | | { |
| | | if (inArray(paramName, vProtocolAtts)) |
| | | { |
| | | if (allowedAttribute(name, paramName)) { |
| | | if (inArray(paramName, vProtocolAtts)) { |
| | | paramValue = processParamProtocol(paramValue); |
| | | } |
| | | params.append(' ').append(paramName).append("=\"").append(paramValue).append("\""); |
| | | } |
| | | } |
| | | |
| | | if (inArray(name, vSelfClosingTags)) |
| | | { |
| | | if (inArray(name, vSelfClosingTags)) { |
| | | ending = " /"; |
| | | } |
| | | |
| | | if (inArray(name, vNeedClosingTags)) |
| | | { |
| | | if (inArray(name, vNeedClosingTags)) { |
| | | ending = ""; |
| | | } |
| | | |
| | | if (ending == null || ending.length() < 1) |
| | | { |
| | | if (vTagCounts.containsKey(name)) |
| | | { |
| | | if (ending == null || ending.length() < 1) { |
| | | if (vTagCounts.containsKey(name)) { |
| | | vTagCounts.put(name, vTagCounts.get(name) + 1); |
| | | } |
| | | else |
| | | { |
| | | } else { |
| | | vTagCounts.put(name, 1); |
| | | } |
| | | } |
| | | else |
| | | { |
| | | } else { |
| | | ending = " /"; |
| | | } |
| | | return "<" + name + params + ending + ">"; |
| | | } |
| | | else |
| | | { |
| | | } else { |
| | | return ""; |
| | | } |
| | | } |
| | | |
| | | // comments |
| | | m = P_COMMENT.matcher(s); |
| | | if (!stripComment && m.find()) |
| | | { |
| | | if (!stripComment && m.find()) { |
| | | return "<" + m.group() + ">"; |
| | | } |
| | | |
| | | return ""; |
| | | } |
| | | |
| | | private String processParamProtocol(String s) |
| | | { |
| | | private String processParamProtocol(String s) { |
| | | s = decodeEntities(s); |
| | | final Matcher m = P_PROTOCOL.matcher(s); |
| | | if (m.find()) |
| | | { |
| | | if (m.find()) { |
| | | final String protocol = m.group(1); |
| | | if (!inArray(protocol, vAllowedProtocols)) |
| | | { |
| | | if (!inArray(protocol, vAllowedProtocols)) { |
| | | // bad protocol, turn into local anchor link instead |
| | | s = "#" + s.substring(protocol.length() + 1); |
| | | if (s.startsWith("#//")) |
| | | { |
| | | if (s.startsWith("#//")) { |
| | | s = "#" + s.substring(3); |
| | | } |
| | | } |
| | |
| | | return s; |
| | | } |
| | | |
| | | private String decodeEntities(String s) |
| | | { |
| | | private String decodeEntities(String s) { |
| | | StringBuffer buf = new StringBuffer(); |
| | | |
| | | Matcher m = P_ENTITY.matcher(s); |
| | | while (m.find()) |
| | | { |
| | | while (m.find()) { |
| | | final String match = m.group(1); |
| | | final int decimal = Integer.decode(match).intValue(); |
| | | m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal))); |
| | |
| | | |
| | | buf = new StringBuffer(); |
| | | m = P_ENTITY_UNICODE.matcher(s); |
| | | while (m.find()) |
| | | { |
| | | while (m.find()) { |
| | | final String match = m.group(1); |
| | | final int decimal = Integer.valueOf(match, 16).intValue(); |
| | | m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal))); |
| | |
| | | |
| | | buf = new StringBuffer(); |
| | | m = P_ENCODE.matcher(s); |
| | | while (m.find()) |
| | | { |
| | | while (m.find()) { |
| | | final String match = m.group(1); |
| | | final int decimal = Integer.valueOf(match, 16).intValue(); |
| | | m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal))); |
| | |
| | | return s; |
| | | } |
| | | |
| | | private String validateEntities(final String s) |
| | | { |
| | | private String validateEntities(final String s) { |
| | | StringBuffer buf = new StringBuffer(); |
| | | |
| | | // validate entities throughout the string |
| | | Matcher m = P_VALID_ENTITIES.matcher(s); |
| | | while (m.find()) |
| | | { |
| | | while (m.find()) { |
| | | final String one = m.group(1); // ([^&;]*) |
| | | final String two = m.group(2); // (?=(;|&|$)) |
| | | m.appendReplacement(buf, Matcher.quoteReplacement(checkEntity(one, two))); |
| | |
| | | return encodeQuotes(buf.toString()); |
| | | } |
| | | |
| | | private String encodeQuotes(final String s) |
| | | { |
| | | if (encodeQuotes) |
| | | { |
| | | private String encodeQuotes(final String s) { |
| | | if (encodeQuotes) { |
| | | StringBuffer buf = new StringBuffer(); |
| | | Matcher m = P_VALID_QUOTES.matcher(s); |
| | | while (m.find()) |
| | | { |
| | | while (m.find()) { |
| | | final String one = m.group(1); // (>|^) |
| | | final String two = m.group(2); // ([^<]+?) |
| | | final String three = m.group(3); // (<|$) |
| | |
| | | } |
| | | m.appendTail(buf); |
| | | return buf.toString(); |
| | | } |
| | | else |
| | | { |
| | | } else { |
| | | return s; |
| | | } |
| | | } |
| | | |
| | | private String checkEntity(final String preamble, final String term) |
| | | { |
| | | private String checkEntity(final String preamble, final String term) { |
| | | |
| | | return ";".equals(term) && isValidEntity(preamble) ? '&' + preamble : "&" + preamble; |
| | | } |
| | | |
| | | private boolean isValidEntity(final String entity) |
| | | { |
| | | private boolean isValidEntity(final String entity) { |
| | | return inArray(entity, vAllowedEntities); |
| | | } |
| | | |
| | | private static boolean inArray(final String s, final String[] array) |
| | | { |
| | | for (String item : array) |
| | | { |
| | | if (item != null && item.equals(s)) |
| | | { |
| | | return true; |
| | | } |
| | | } |
| | | return false; |
| | | } |
| | | |
| | | private boolean allowed(final String name) |
| | | { |
| | | private boolean allowed(final String name) { |
| | | return (vAllowed.isEmpty() || vAllowed.containsKey(name)) && !inArray(name, vDisallowed); |
| | | } |
| | | |
| | | private boolean allowedAttribute(final String name, final String paramName) |
| | | { |
| | | private boolean allowedAttribute(final String name, final String paramName) { |
| | | return allowed(name) && (vAllowed.isEmpty() || vAllowed.get(name).contains(paramName)); |
| | | } |
| | | } |