XSS过滤JAVA过滤器filter 防止常见SQL注入分析

哈哈 阅读:242 2020-04-22 14:13:35 评论:0

Java项目中XSS过滤器的使用方法。

简单介绍:

XSS : 跨站脚本攻击(Cross Site Scripting),为不和层叠样式表(Cascading Style Sheets, CSS)的缩写混淆,故将跨站脚本攻击缩写为XSS。恶意攻击者往Web页面里插入恶意html代码,当用户浏览该页之时,嵌入其中Web里面的html代码会被执行,从而达到恶意攻击用户的特殊目的。

sql注入
所谓SQL注入,就是通过把SQL命令插入到Web表单提交或输入域名或页面请求的查询字符串,最终达到欺骗服务器执行恶意的SQL命令。具体来说,它是利用现有应用程序,将(恶意)的SQL命令注入到后台数据库引擎执行的能力,它可以通过在Web表单中输入(恶意)SQL语句得到一个存在安全漏洞的网站上的数据库,而不是按照设计者意图去执行SQL语句。

实现方式,共三步:

第一步:配置web.xml

<filter> 
    <filter-name>xssFilter</filter-name> 
    <filter-class>com.wfcm.xss.XssFilter</filter-class> 
  </filter> 
  <filter-mapping> 
    <filter-name>xssFilter</filter-name> 
    <url-pattern>/*</url-pattern> 
  </filter-mapping>

 

第二步:过滤工具类

1.XSSFilter.java

package com.wfcm.xss; 
 
import javax.servlet.*; 
import javax.servlet.http.HttpServletRequest; 
import java.io.IOException; 
 
 
/** 
 * xss过滤 
 * @author xlf 
 * @email [email protected] 
 * @date 2017年4月19日 上午10:41:42 
 */ 
public class XssFilter implements Filter { 
 
    @Override 
    public void init(FilterConfig config) throws ServletException { 
    } 
 
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 
            throws IOException, ServletException { 
         
         
        XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper( 
                (HttpServletRequest) request); 
        chain.doFilter(xssRequest, response); 
    } 
 
    @Override 
    public void destroy() { 
    } 
 
}
View Code

 

2.XssHttpServletRequestWrapper

package com.wfcm.xss; 
 
import org.apache.commons.lang.StringEscapeUtils; 
import org.apache.commons.lang.StringUtils; 
 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletRequestWrapper; 
import java.util.LinkedHashMap; 
import java.util.Map; 
 
public class XssHttpServletRequestWrapper  extends HttpServletRequestWrapper { 
 
    // 没被包装过的HttpServletRequest(特殊场景,需求自己过滤) 
        HttpServletRequest orgRequest; 
        // html过滤 
        private final static HTMLFilter htmlFilter = new HTMLFilter(); 
 
        public XssHttpServletRequestWrapper(HttpServletRequest request) { 
            super(request); 
            orgRequest = request; 
        } 
 
        @Override 
        public String getParameter(String name) { 
            String value = super.getParameter(xssEncode(name)); 
            if (StringUtils.isNotBlank(value)) { 
                value =xssEncode(value); 
            } 
 
            //SQL注入检查 
//            value = SQLFilter.sqlInject(value); 
            value = SQLFilter.sqlInject(value); 
 
            return StringEscapeUtils.unescapeHtml(value); 
        } 
 
        @Override 
        public String[] getParameterValues(String name) { 
            String[] parameters = super.getParameterValues(name); 
            if (parameters == null || parameters.length == 0) { 
                return null; 
            } 
 
            for (int i = 0; i < parameters.length; i++) { 
                parameters[i] = xssEncode(parameters[i]); 
                //SQL注入检查 
//                parameters[i] = SQLFilter.sqlInject(parameters[i]); 
                parameters[i] = SQLFilter.sqlInject(parameters[i]); 
                parameters[i] = StringEscapeUtils.unescapeHtml(parameters[i]); 
            } 
            return parameters; 
        } 
 
        @Override 
        public Map<String, String[]> getParameterMap() { 
            Map<String, String[]> map = new LinkedHashMap<>(); 
            Map<String, String[]> parameters = super.getParameterMap(); 
            for (String key : parameters.keySet()) { 
                String[] values = parameters.get(key); 
                for (int i = 0; i < values.length; i++) { 
                    values[i] = xssEncode(values[i]); 
                    //SQL注入检查 
//                    values[i] = SQLFilter.sqlInject(values[i]); 
                    values[i] = SQLFilter.sqlInject(values[i]); 
                    values[i] = StringEscapeUtils.unescapeHtml(values[i]); 
                } 
                map.put(key, values); 
            } 
            return map; 
        } 
 
        @Override 
        public String getHeader(String name) { 
            String value = super.getHeader(xssEncode(name)); 
            if (StringUtils.isNotBlank(value)) { 
                value = xssEncode(value); 
            } 
             
            //SQL注入检查 
//                    value = SQLFilter.sqlInject(value); 
            value = SQLFilter.sqlInject(value); 
            return StringEscapeUtils.unescapeHtml(value); 
        } 
 
        private String xssEncode(String input) { 
            return htmlFilter.filter(input); 
        } 
 
        /** 
         * 获取最原始的request 
         */ 
        public HttpServletRequest getOrgRequest() { 
            return orgRequest; 
        } 
 
        /** 
         * 获取最原始的request 
         */ 
        public static HttpServletRequest getOrgRequest(HttpServletRequest request) { 
            if (request instanceof XssHttpServletRequestWrapper) { 
                return ((XssHttpServletRequestWrapper) request).getOrgRequest(); 
            } 
 
            return request; 
        } 
 
}
View Code

 

3.HTMLFilter

package com.wfcm.xss; 
 
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.logging.Logger; 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
/** 
* 
* HTML filtering utility for protecting against XSS (Cross Site Scripting). 
* 
* This code is licensed LGPLv3 
* 
* This code is a Java port of the original work in PHP by Cal Hendersen. 
* http://code.iamcal.com/php/lib_filter/ 
* 
* The trickiest part of the translation was handling the differences in regex handling 
* between PHP and Java.  These resources were helpful in the process: 
* 
* http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/Pattern.html 
* http://us2.php.net/manual/en/reference.pcre.pattern.modifiers.php 
* http://www.regular-expressions.info/modifiers.html 
* 
* A note on naming conventions: instance variables are prefixed with a "v"; global 
* constants are in all caps. 
* 
* Sample use: 
* String input = ... 
* String clean = new HTMLFilter().filter( input ); 
* 
* The class is not thread safe. Create a new instance if in doubt. 
* 
* If you find bugs or have suggestions on improvement (especially regarding 
* performance), please contact us.  The latest version of this 
* source, and our contact details, can be found at http://xss-html-filter.sf.net 
* 
* @author Joseph O'Connell 
* @author Cal Hendersen 
* @author Michael Semb Wever 
*/ 
public 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("<>"); 
    private static final Pattern P_DOUBLE_QUOT = Pattern.compile("&quot;"); 
 
    // @xxx could grow large... maybe use sesat's ReferenceMap 
    private static final ConcurrentMap<String,Pattern> P_REMOVE_PAIR_BLANKS = new ConcurrentHashMap<String, Pattern>(); 
    private static final ConcurrentMap<String,Pattern> P_REMOVE_SELF_BLANKS = new ConcurrentHashMap<String, Pattern>(); 
 
    /** set of allowed html elements, along with allowed attributes for each element **/ 
    private final Map<String, List<String>> vAllowed; 
    /** counts of open tags for each (allowable) html element **/ 
    private final Map<String, Integer> vTagCounts = new HashMap<String, Integer>(); 
 
    /** html elements which must always be self-closing (e.g. "<img />") **/ 
    private final String[] vSelfClosingTags; 
    /** html elements which must always have separate opening and closing tags (e.g. "<b></b>") **/ 
    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. "<b></b>" or "<b />") **/ 
    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; 
    private boolean vDebug = false; 
    /** 
     * flag determining whether to try to make tags when presented with "unbalanced" 
     * angle brackets (e.g. "<b text </b>" becomes "<b> text </b>").  If set to false, 
     * unbalanced angle brackets will be html escaped. 
     */ 
    private final boolean alwaysMakeTags; 
 
    /** Default constructor. 
     * 
     */ 
    public HTMLFilter() { 
        vAllowed = new HashMap<>(); 
 
        final ArrayList<String> a_atts = new ArrayList<String>(); 
        a_atts.add("href"); 
        a_atts.add("target"); 
        vAllowed.put("a", a_atts); 
 
        final ArrayList<String> img_atts = new ArrayList<String>(); 
        img_atts.add("src"); 
        img_atts.add("width"); 
        img_atts.add("height"); 
        img_atts.add("alt"); 
        vAllowed.put("img", img_atts); 
 
        final ArrayList<String> no_atts = new ArrayList<String>(); 
        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; 
    } 
 
    /** Set debug flag to true. Otherwise use default settings. See the default constructor. 
     * 
     * @param debug turn debug on with a true argument 
     */ 
    public HTMLFilter(final boolean debug) { 
        this(); 
        vDebug = debug; 
 
    } 
 
    /** Map-parameter configurable constructor. 
     * 
     * @param conf map containing configuration. keys match field names. 
     */ 
    public HTMLFilter(final Map<String,Object> 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<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(); 
    } 
 
    private void debug(final String msg) { 
        if (vDebug) { 
            Logger.getAnonymousLogger().info(msg); 
        } 
    } 
 
    //--------------------------------------------------------------- 
    // 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, "&amp;", result); 
        result = regexReplace(P_QUOTE, "&quot;", result); 
        result = regexReplace(P_LEFT_ARROW, "&lt;", result); 
        result = regexReplace(P_RIGHT_ARROW, "&gt;", 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; 
 
        debug("************************************************"); 
        debug("              INPUT: " + input); 
 
        s = escapeComments(s); 
        debug("     escapeComments: " + s); 
 
        s = balanceHTML(s); 
        debug("        balanceHTML: " + s); 
 
        s = checkTags(s); 
        debug("          checkTags: " + s); 
 
        s = processRemoveBlanks(s); 
        debug("processRemoveBlanks: " + s); 
 
        s = validateEntities(s); 
        debug("    validateEntites: " + s); 
 
        debug("************************************************\n\n"); 
        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("<!--" + htmlSpecialChars(match) + "-->")); 
        } 
        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, "&lt;$1", s); 
            s = regexReplace(P_STRAY_RIGHT_ARROW, "$1$2&gt;<", 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); 
 
        s = buf.toString(); 
 
        // these get tallied in processTag 
        // (remember to reset before subsequent calls to filter method) 
        for (String key : vTagCounts.keySet()) { 
            for (int ii = 0; ii < vTagCounts.get(key); ii++) { 
                s += "</" + key + ">"; 
            } 
        } 
 
        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[^>]*)?></" + tag + ">")); 
            } 
            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 (!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()) { 
            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)) { 
                String params = ""; 
 
                final Matcher m2 = P_QUOTED_ATTRIBUTES.matcher(body); 
                final Matcher m3 = P_UNQUOTED_ATTRIBUTES.matcher(body); 
                final List<String> paramNames = new ArrayList<String>(); 
                final List<String> paramValues = new ArrayList<String>(); 
                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 += " " + paramName + "=\"" + paramValue + "\""; 
                    } 
                } 
 
                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, s.length()); 
                if (s.startsWith("#//")) { 
                    s = "#" + s.substring(3, s.length()); 
                } 
            } 
        } 
 
        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, "&quot;", 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 
                : "&amp;" + 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)); 
    } 
}
View Code

 

4.SQLFilter

package com.wfcm.xss; 
 
import org.apache.commons.lang.StringUtils; 
 
import com.wfcm.utils.RRException; 
 
/** 
 * sql过滤 
 *  
 * @author xlf 
 * @email [email protected] 
 * @date 2017年4月19日 上午10:41:25 
 */ 
public class SQLFilter { 
 
    /** 
     * SQL注入过滤 
     *  
     * @param str 
     *            待验证的字符串 
     */ 
    public static String sqlInject(String str) { 
        if (StringUtils.isBlank(str)) { 
            return null; 
        } 
        // 去掉'|"|;|\字符 
        str = StringUtils.replace(str, "'", ""); 
        str = StringUtils.replace(str, "\"", ""); 
        str = StringUtils.replace(str, ";", ""); 
        str = StringUtils.replace(str, "\\", ""); 
 
        // 转换成小写 
        str = str.toLowerCase(); 
 
        // 非法字符 
        String[] keywords = { "master", "truncate", "insert", "select", "delete", "update", "declare", "alert", 
                "create", "drop" }; 
        // 判断是否包含非法字符 
        for (String keyword : keywords) { 
            if (str.equals(keyword)) { 
                throw new RRException("包含非法字符", 1); 
            } 
        } 
 
        return str; 
    } 
}
View Code

 

第三步:大功告成!!

 

标签:java
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