From 8bc7296fb4f8d87fc514a7ef04b8a419948de836 Mon Sep 17 00:00:00 2001 From: RuoYi Date: Fri, 20 Dec 2019 11:34:45 +0800 Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0HTML=E8=BF=87=E6=BB=A4?= =?UTF-8?q?=E5=99=A8=EF=BC=8C=E7=94=A8=E4=BA=8E=E5=8E=BB=E9=99=A4XSS?= =?UTF-8?q?=E6=BC=8F=E6=B4=9E=E9=9A=90=E6=82=A3?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../ruoyi/common/utils/html/EscapeUtil.java | 2 +- .../ruoyi/common/utils/html/HTMLFilter.java | 568 ++++++++++++++++++ 2 files changed, 569 insertions(+), 1 deletion(-) create mode 100644 ruoyi/src/main/java/com/ruoyi/common/utils/html/HTMLFilter.java diff --git a/ruoyi/src/main/java/com/ruoyi/common/utils/html/EscapeUtil.java b/ruoyi/src/main/java/com/ruoyi/common/utils/html/EscapeUtil.java index f6754c4..0f45527 100644 --- a/ruoyi/src/main/java/com/ruoyi/common/utils/html/EscapeUtil.java +++ b/ruoyi/src/main/java/com/ruoyi/common/utils/html/EscapeUtil.java @@ -58,7 +58,7 @@ public class EscapeUtil */ public static String clean(String content) { - return content.replaceAll(RE_HTML_MARK, ""); + return new HTMLFilter().filter(content); } /** diff --git a/ruoyi/src/main/java/com/ruoyi/common/utils/html/HTMLFilter.java b/ruoyi/src/main/java/com/ruoyi/common/utils/html/HTMLFilter.java new file mode 100644 index 0000000..e99e487 --- /dev/null +++ b/ruoyi/src/main/java/com/ruoyi/common/utils/html/HTMLFilter.java @@ -0,0 +1,568 @@ +package com.ruoyi.common.utils.html; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentMap; +import java.util.regex.Matcher; +import java.util.regex.Pattern; + +/** + * HTML过滤器，用于去除XSS漏洞隐患。 + * + * @author ruoyi + */ +public final class HTMLFilter +{ + /** + * regex flag union representing /si modifiers in php + **/ + private static final int REGEX_FLAGS_SI = Pattern.CASE_INSENSITIVE | Pattern.DOTALL; + private static final Pattern P_COMMENTS = Pattern.compile("", Pattern.DOTALL); + private static final Pattern P_COMMENT = Pattern.compile("^!--(.*)--$", REGEX_FLAGS_SI); + private static final Pattern P_TAGS = Pattern.compile("<(.*?)>", Pattern.DOTALL); + private static final Pattern P_END_TAG = Pattern.compile("^/([a-z0-9]+)", REGEX_FLAGS_SI); + private static final Pattern P_START_TAG = Pattern.compile("^([a-z0-9]+)(.*?)(/?)$", REGEX_FLAGS_SI); + private static final Pattern P_QUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)=([\"'])(.*?)\\2", REGEX_FLAGS_SI); + private static final Pattern P_UNQUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)(=)([^\"\\s']+)", REGEX_FLAGS_SI); + private static final Pattern P_PROTOCOL = Pattern.compile("^([^:]+):", REGEX_FLAGS_SI); + private static final Pattern P_ENTITY = Pattern.compile("&#(\\d+);?"); + private static final Pattern P_ENTITY_UNICODE = Pattern.compile("&#x([0-9a-f]+);?"); + private static final Pattern P_ENCODE = Pattern.compile("%([0-9a-f]{2});?"); + private static final Pattern P_VALID_ENTITIES = Pattern.compile("&([^&;]*)(?=(;|&|$))"); + private static final Pattern P_VALID_QUOTES = Pattern.compile("(>|^)([^<]+?)(<|$)", Pattern.DOTALL); + private static final Pattern P_END_ARROW = Pattern.compile("^>"); + private static final Pattern P_BODY_TO_END = Pattern.compile("<([^>]*?)(?=<|$)"); + private static final Pattern P_XML_CONTENT = Pattern.compile("(^|>)([^<]*?)(?=>)"); + private static final Pattern P_STRAY_LEFT_ARROW = Pattern.compile("<([^>]*?)(?=<|$)"); + private static final Pattern P_STRAY_RIGHT_ARROW = Pattern.compile("(^|>)([^<]*?)(?=>)"); + private static final Pattern P_AMP = Pattern.compile("&"); + private static final Pattern P_QUOTE = Pattern.compile("\""); + private static final Pattern P_LEFT_ARROW = Pattern.compile("<"); + private static final Pattern P_RIGHT_ARROW = Pattern.compile(">"); + private static final Pattern P_BOTH_ARROWS = Pattern.compile("<>"); + + // @xxx could grow large... maybe use sesat's ReferenceMap + private static final ConcurrentMap P_REMOVE_PAIR_BLANKS = new ConcurrentHashMap<>(); + private static final ConcurrentMap P_REMOVE_SELF_BLANKS = new ConcurrentHashMap<>(); + + /** + * set of allowed html elements, along with allowed attributes for each element + **/ + private final Map> vAllowed; + /** + * counts of open tags for each (allowable) html element + **/ + private final Map vTagCounts = new HashMap<>(); + + /** + * html elements which must always be self-closing (e.g. "") + **/ + private final String[] vSelfClosingTags; + /** + * html elements which must always have separate opening and closing tags (e.g. "") + **/ + private final String[] vNeedClosingTags; + /** + * set of disallowed html elements + **/ + private final String[] vDisallowed; + /** + * attributes which should be checked for valid protocols + **/ + private final String[] vProtocolAtts; + /** + * allowed protocols + **/ + private final String[] vAllowedProtocols; + /** + * tags which should be removed if they contain no content (e.g. "" or "") + **/ + private final String[] vRemoveBlanks; + /** + * entities allowed within html markup + **/ + private final String[] vAllowedEntities; + /** + * flag determining whether comments are allowed in input String. + */ + private final boolean stripComment; + private final boolean encodeQuotes; + /** + * flag determining whether to try to make tags when presented with "unbalanced" angle brackets (e.g. "" + * becomes " text "). If set to false, unbalanced angle brackets will be html escaped. + */ + private final boolean alwaysMakeTags; + + /** + * Default constructor. + */ + public HTMLFilter() + { + vAllowed = new HashMap<>(); + + final ArrayList a_atts = new ArrayList<>(); + a_atts.add("href"); + a_atts.add("target"); + vAllowed.put("a", a_atts); + + final ArrayList img_atts = new ArrayList<>(); + img_atts.add("src"); + img_atts.add("width"); + img_atts.add("height"); + img_atts.add("alt"); + vAllowed.put("img", img_atts); + + final ArrayList no_atts = new ArrayList<>(); + vAllowed.put("b", no_atts); + vAllowed.put("strong", no_atts); + vAllowed.put("i", no_atts); + vAllowed.put("em", no_atts); + + 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" }; + stripComment = true; + encodeQuotes = true; + alwaysMakeTags = true; + } + + /** + * Map-parameter configurable constructor. + * + * @param conf map containing configuration. keys match field names. + */ + @SuppressWarnings("unchecked") + public HTMLFilter(final Map conf) + { + + assert conf.containsKey("vAllowed") : "configuration requires vAllowed"; + assert conf.containsKey("vSelfClosingTags") : "configuration requires vSelfClosingTags"; + assert conf.containsKey("vNeedClosingTags") : "configuration requires vNeedClosingTags"; + assert conf.containsKey("vDisallowed") : "configuration requires vDisallowed"; + assert conf.containsKey("vAllowedProtocols") : "configuration requires vAllowedProtocols"; + assert conf.containsKey("vProtocolAtts") : "configuration requires vProtocolAtts"; + assert conf.containsKey("vRemoveBlanks") : "configuration requires vRemoveBlanks"; + assert conf.containsKey("vAllowedEntities") : "configuration requires vAllowedEntities"; + + vAllowed = Collections.unmodifiableMap((HashMap>) 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(); + } + + // --------------------------------------------------------------- + // my versions of some PHP library functions + public static String chr(final int decimal) + { + return String.valueOf((char) decimal); + } + + public static String htmlSpecialChars(final String s) + { + String result = s; + result = regexReplace(P_AMP, "&", result); + result = regexReplace(P_QUOTE, """, result); + result = regexReplace(P_LEFT_ARROW, "<", result); + result = regexReplace(P_RIGHT_ARROW, ">", result); + return result; + } + + // --------------------------------------------------------------- + + /** + * 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 + * @return "clean" version of input, with only valid, whitelisted html elements allowed + */ + public String filter(final String input) + { + reset(); + String s = input; + + s = escapeComments(s); + + s = balanceHTML(s); + + s = checkTags(s); + + s = processRemoveBlanks(s); + + s = validateEntities(s); + + return s; + } + + public boolean isAlwaysMakeTags() + { + return alwaysMakeTags; + } + + public boolean isStripComments() + { + return stripComment; + } + + private String escapeComments(final String s) + { + final Matcher m = P_COMMENTS.matcher(s); + final StringBuffer buf = new StringBuffer(); + if (m.find()) + { + final String match = m.group(1); // (.*?) + m.appendReplacement(buf, Matcher.quoteReplacement("")); + } + m.appendTail(buf); + + return buf.toString(); + } + + private String balanceHTML(String s) + { + if (alwaysMakeTags) + { + // + // try and form html + // + s = regexReplace(P_END_ARROW, "", s); + s = regexReplace(P_BODY_TO_END, "<$1>", s); + s = regexReplace(P_XML_CONTENT, "$1<$2", s); + + } + else + { + // + // escape stray brackets + // + s = regexReplace(P_STRAY_LEFT_ARROW, "<$1", s); + s = regexReplace(P_STRAY_RIGHT_ARROW, "$1$2><", s); + + // + // the last regexp causes '<>' entities to appear + // (we need to do a lookahead assertion so that the last bracket can + // be used in the next pass of the regexp) + // + s = regexReplace(P_BOTH_ARROWS, "", s); + } + + return s; + } + + private String checkTags(String s) + { + Matcher m = P_TAGS.matcher(s); + + final StringBuffer buf = new StringBuffer(); + while (m.find()) + { + String replaceStr = m.group(1); + replaceStr = processTag(replaceStr); + m.appendReplacement(buf, Matcher.quoteReplacement(replaceStr)); + } + m.appendTail(buf); + + // 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++) + { + sBuilder.append(""); + } + } + s = sBuilder.toString(); + + return s; + } + + private String processRemoveBlanks(final String s) + { + String result = s; + for (String tag : vRemoveBlanks) + { + if (!P_REMOVE_PAIR_BLANKS.containsKey(tag)) + { + P_REMOVE_PAIR_BLANKS.putIfAbsent(tag, Pattern.compile("<" + tag + "(\\s[^>]*)?>")); + } + result = regexReplace(P_REMOVE_PAIR_BLANKS.get(tag), "", result); + 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) + { + // ending tags + Matcher m = P_END_TAG.matcher(s); + if (m.find()) + { + final String name = m.group(1).toLowerCase(); + if (allowed(name)) + { + if (false == inArray(name, vSelfClosingTags)) + { + if (vTagCounts.containsKey(name)) + { + vTagCounts.put(name, vTagCounts.get(name) - 1); + return ""; + } + } + } + } + + // starting tags + m = P_START_TAG.matcher(s); + 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)) + { + final StringBuilder params = new StringBuilder(); + + final Matcher m2 = P_QUOTED_ATTRIBUTES.matcher(body); + final Matcher m3 = P_UNQUOTED_ATTRIBUTES.matcher(body); + final List paramNames = new ArrayList<>(); + final List paramValues = new ArrayList<>(); + while (m2.find()) + { + paramNames.add(m2.group(1)); // ([a-z0-9]+) + paramValues.add(m2.group(3)); // (.*?) + } + 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++) + { + paramName = paramNames.get(ii).toLowerCase(); + paramValue = paramValues.get(ii); + + // debug( "paramName='" + paramName + "'" ); + // debug( "paramValue='" + paramValue + "'" ); + // debug( "allowed? " + vAllowed.get( name ).contains( paramName ) ); + + if (allowedAttribute(name, paramName)) + { + if (inArray(paramName, vProtocolAtts)) + { + paramValue = processParamProtocol(paramValue); + } + params.append(' ').append(paramName).append("=\"").append(paramValue).append("\""); + } + } + + if (inArray(name, vSelfClosingTags)) + { + ending = " /"; + } + + if (inArray(name, vNeedClosingTags)) + { + ending = ""; + } + + if (ending == null || ending.length() < 1) + { + if (vTagCounts.containsKey(name)) + { + vTagCounts.put(name, vTagCounts.get(name) + 1); + } + else + { + vTagCounts.put(name, 1); + } + } + else + { + ending = " /"; + } + return "<" + name + params + ending + ">"; + } + else + { + return ""; + } + } + + // comments + m = P_COMMENT.matcher(s); + if (!stripComment && m.find()) + { + return "<" + m.group() + ">"; + } + + return ""; + } + + private String processParamProtocol(String s) + { + s = decodeEntities(s); + final Matcher m = P_PROTOCOL.matcher(s); + if (m.find()) + { + final String protocol = m.group(1); + if (!inArray(protocol, vAllowedProtocols)) + { + // bad protocol, turn into local anchor link instead + s = "#" + s.substring(protocol.length() + 1); + if (s.startsWith("#//")) + { + s = "#" + s.substring(3); + } + } + } + + return s; + } + + private String decodeEntities(String s) + { + StringBuffer buf = new StringBuffer(); + + Matcher m = P_ENTITY.matcher(s); + while (m.find()) + { + final String match = m.group(1); + final int decimal = Integer.decode(match).intValue(); + m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal))); + } + m.appendTail(buf); + s = buf.toString(); + + buf = new StringBuffer(); + m = P_ENTITY_UNICODE.matcher(s); + while (m.find()) + { + final String match = m.group(1); + final int decimal = Integer.valueOf(match, 16).intValue(); + m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal))); + } + m.appendTail(buf); + s = buf.toString(); + + buf = new StringBuffer(); + m = P_ENCODE.matcher(s); + while (m.find()) + { + final String match = m.group(1); + final int decimal = Integer.valueOf(match, 16).intValue(); + m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal))); + } + m.appendTail(buf); + s = buf.toString(); + + s = validateEntities(s); + return 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()) + { + final String one = m.group(1); // ([^&;]*) + final String two = m.group(2); // (?=(;|&|$)) + m.appendReplacement(buf, Matcher.quoteReplacement(checkEntity(one, two))); + } + m.appendTail(buf); + + return encodeQuotes(buf.toString()); + } + + private String encodeQuotes(final String s) + { + if (encodeQuotes) + { + StringBuffer buf = new StringBuffer(); + Matcher m = P_VALID_QUOTES.matcher(s); + while (m.find()) + { + final String one = m.group(1); // (>|^) + final String two = m.group(2); // ([^<]+?) + final String three = m.group(3); // (<|$) + m.appendReplacement(buf, Matcher.quoteReplacement(one + regexReplace(P_QUOTE, """, two) + three)); + } + m.appendTail(buf); + return buf.toString(); + } + else + { + return s; + } + } + + private String checkEntity(final String preamble, final String term) + { + + return ";".equals(term) && isValidEntity(preamble) ? '&' + preamble : "&" + preamble; + } + + 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) + { + return (vAllowed.isEmpty() || vAllowed.containsKey(name)) && !inArray(name, vDisallowed); + } + + private boolean allowedAttribute(final String name, final String paramName) + { + return allowed(name) && (vAllowed.isEmpty() || vAllowed.get(name).contains(paramName)); + } +} \ No newline at end of file