使用antisamy防止xss注入

時間  2019-11-13
標籤 使用 antisamy 防止 xss 注入 欄目 JavaScript 简体版
原文   原文鏈接

  1. 添加maven依賴html

    <dependency>
		<groupId>org.owasp.antisamy</groupId>
		<artifactId>antisamy</artifactId>
		<version>1.5.8</version>
	</dependency>

  2. 根據antisamy api編寫相關工具類java

    import java.io.IOException;

	import org.owasp.esapi.ESAPI;
	import org.owasp.validator.html.AntiSamy;
	import org.owasp.validator.html.CleanResults;
	import org.owasp.validator.html.Policy;
	import org.owasp.validator.html.PolicyException;
	import org.owasp.validator.html.ScanException;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;
	import org.springframework.core.io.DefaultResourceLoader;
	import org.springframework.core.io.Resource;
	import org.springframework.core.io.ResourceLoader;

	public class XssUtils {

		private final static Logger logger = LoggerFactory.getLogger(XssUtils.class);

		private static Policy policy = null; 

		static{ 
			ResourceLoader resourceLoader = new DefaultResourceLoader();
			Resource resource = resourceLoader.getResource("classpath:/antisamy.xml"); 
			 try { 
				policy = Policy.getInstance(resource.getURL().getPath()); 
			} catch (PolicyException e) { 
				e.printStackTrace(); 
			} catch (IOException e) {
				e.printStackTrace();
			} 
		} 

		public static String encode(String value){
			if(value == null || value.length() == 0) {
				return value;
			}
			value = ESAPI.encoder().canonicalize(value);
			return ESAPI.encoder().encodeForHTML(value);
		}

		public static String[] encode(String[] values){
			if(values == null || values.length == 0){
				return values;
			}
			int len = values.length;
			String[] _values = new String[len];
			for(int i = 0; i < len; i++){
				_values[i] = encode(values[i]);
			}
			return _values;
		}

		public static String clean(String value){
			AntiSamy antiSamy = new AntiSamy(); 
			try { 
				final CleanResults cr = antiSamy.scan(value, policy); 
				return cr.getCleanHTML(); 
			} catch (ScanException | PolicyException e) { 
				logger.error("invoke xss clean error", e);
			} 
			return value;
		}

		public static String[] clean(String[] values){
			if(values == null || values.length == 0){
				return values;
			}
			int len = values.length;
			String[] _values = new String[len];
			for(int i = 0; i < len; i++){
				_values[i] = clean(values[i]);
			}
			return _values;
		}

	}

  3. 使用filter處理HttpServletRequest，依次編寫如下代碼spring

    1. 自定義HttpServletRequestWrapperjson

      import java.util.HashMap;
	import java.util.Map;

	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletRequestWrapper;

	import com.sw.busi.utils.XssUtils;

	public class XssCleanHttpServletRequestWrapper extends HttpServletRequestWrapper {

		public XssCleanHttpServletRequestWrapper(HttpServletRequest request) {
			super(request);
		}

		public String getQueryString() {
			String value = super.getQueryString();
			if (value != null) {
				value = XssUtils.clean(value);
			}
			return value;
		}

		/**
		 * 覆蓋getParameter方法，將參數名和參數值都作xss過濾。<br/>
		 * 若是須要得到原始的值，則經過super.getParameterValues(name)來獲取<br/>
		 * getParameterNames,getParameterValues和getParameterMap也可能須要覆蓋
		 */
		public String getParameter(String name) {
			String value = super.getParameter(XssUtils.clean(name));
			if (value != null) {
				value = XssUtils.clean(value);
			}
			return value;
		}

		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] = XssUtils.clean(parameters[i]);
			}
			return parameters;
		}

		public Map<String, String[]> getParameterMap() {
			Map<String, String[]> params = super.getParameterMap();
			if (params==null || params.size() == 0) {
				return params;
			}
			int capacity = (int) ((float) params.size() / 0.75F + 1.0F);
			Map<String, String[]> _params = new HashMap<String, String[]>(capacity);
			for (Map.Entry<String, String[]> e : params.entrySet()) {
				String key = e.getKey();
				String[] values = e.getValue();
				for (int i = 0; i < values.length; i++) {
					values[i] = XssUtils.clean(values[i]);
				}
				_params.put(key, values);
			}
			return _params;
		}

		/**
		 * 覆蓋getHeader方法，將參數名和參數值都作xss過濾。<br/>
		 * 若是須要得到原始的值，則經過super.getHeaders(name)來獲取<br/> getHeaderNames 也可能須要覆蓋
		 */
		public String getHeader(String name) {

			String value = super.getHeader(XssUtils.clean(name));
			if (value != null) {
				value = XssUtils.clean(value);
			}
			return value;
		}

	}

    2. 自定義filterapi

      import java.io.IOException;

	import javax.servlet.Filter;
	import javax.servlet.FilterChain;
	import javax.servlet.FilterConfig;
	import javax.servlet.ServletException;
	import javax.servlet.ServletRequest;
	import javax.servlet.ServletResponse;
	import javax.servlet.http.HttpServletRequest;

	public class XssFilter implements Filter {

		protected FilterConfig filterConfig = null;

		public void init(FilterConfig filterConfig) throws ServletException {
			this.filterConfig = filterConfig;
		}

		public void destroy() {
			this.filterConfig = null;
		}

		public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {
			chain.doFilter(new XssCleanHttpServletRequestWrapper((HttpServletRequest) request), response);
		}
	}

  4. 若使用spring mvc，且使用了@RequestBody的方式綁定參數（spring內部封裝了httpservletrequest的裝配器，使用了getInputStream的方式獲取請求體，並轉換爲對應的實體），經過filter的方式就沒法知足了，筆者對spring mvc的序列化與反序列化進行了修改，這裏以jackson爲示例，編寫代碼。mvc

    1. 爲MappingJackson2HttpMessageConverter的objectMapper注入自定義的實例對象
    2. 編寫自定義ObjectMapper的實現 
      import com.fasterxml.jackson.databind.ObjectMapper;
	import com.fasterxml.jackson.databind.module.SimpleModule;
	import com.sw.busi.json.jackson.databind.deser.StringDeserializer;
	import com.sw.busi.json.jackson.databind.ser.StringSerializer;

	public class CustomObjectMapper extends ObjectMapper {
		private static final long serialVersionUID = -8543006375974774016L;

		public CustomObjectMapper(){
			SimpleModule simpleModule = new SimpleModule();
			//序列化與反序列化字符串，使用了xss clean
			simpleModule.addSerializer(String.class, StringSerializer.instance);
			simpleModule.addDeserializer(String.class, StringDeserializer.instance);

			this.registerModule(simpleModule);
		}
	}
    3. 編寫自定義StringSerializer 
      import java.io.IOException;
	import java.lang.reflect.Type;

	import com.fasterxml.jackson.core.*;

	import com.fasterxml.jackson.databind.JavaType;
	import com.fasterxml.jackson.databind.JsonMappingException;
	import com.fasterxml.jackson.databind.JsonNode;
	import com.fasterxml.jackson.databind.SerializerProvider;
	import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
	import com.fasterxml.jackson.databind.ser.std.NonTypedScalarSerializerBase;
	import com.sw.busi.utils.XssUtils;

	/**
	 * This is the special serializer for regular {@link java.lang.String}s.
	 *<p>
	 * Since this is one of "native" types, no type information is ever
	 * included on serialization (unlike for most scalar types as of 1.5)
	 */
	public final class StringSerializer extends NonTypedScalarSerializerBase<String> {
		private static final long serialVersionUID = 1L;

		public static final StringSerializer instance = new StringSerializer();

		public StringSerializer() {
			super(String.class);
		}

		/**
		 * For Strings, both null and Empty String qualify for emptiness.
		 */
		@Override
		@Deprecated
		public boolean isEmpty(String value) {
			return (value == null) || (value.length() == 0);
		}

		@Override
		public boolean isEmpty(SerializerProvider prov, String value) {
			return (value == null) || (value.length() == 0);
		}

		@Override
		public void serialize(String value, JsonGenerator jgen, SerializerProvider provider) throws IOException {
			jgen.writeString(XssUtils.clean(value));
		}

		@Override
		public JsonNode getSchema(SerializerProvider provider, Type typeHint) {
			return createSchemaNode("string", true);
		}

		@Override
		public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint)
				throws JsonMappingException {
			if (visitor != null)
				visitor.expectStringFormat(typeHint);
		}
	}
    4. 編寫StringDeserializer 
      import java.io.IOException;

	import com.fasterxml.jackson.core.Base64Variants;
	import com.fasterxml.jackson.core.JsonParser;
	import com.fasterxml.jackson.core.JsonToken;
	import com.fasterxml.jackson.databind.DeserializationContext;
	import com.fasterxml.jackson.databind.DeserializationFeature;
	import com.fasterxml.jackson.databind.deser.std.StdScalarDeserializer;
	import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;

	import com.sw.busi.utils.XssUtils;

	//去掉註解，防止自定義反序列化器被認爲是標準實現，從而反序列化String[] collection<String> Map<*, String> 無效
	// com.fasterxml.jackson.databind.util.ClassUtil.isJacksonStdImpl(Object)
	//@JacksonStdImpl
	public class StringDeserializer extends StdScalarDeserializer<String> {
		private static final long serialVersionUID = 1L;

		public final static StringDeserializer instance = new StringDeserializer();

		public StringDeserializer() {
			super(String.class);
		}

		// since 2.6, slightly faster lookups for this very common type
		@Override
		public boolean isCachable() {
			return true;
		}

		public String deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {
			JsonToken curr = jp.getCurrentToken();
			if (curr == JsonToken.VALUE_STRING) {
				return XssUtils.clean(jp.getText());
			}

			// Issue#381
			if (curr == JsonToken.START_ARRAY && ctxt.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)) {
				jp.nextToken();
				final String parsed = _parseString(jp, ctxt);
				if (jp.nextToken() != JsonToken.END_ARRAY) {
					throw ctxt.wrongTokenException(jp, JsonToken.END_ARRAY,
							"Attempted to unwrap single value array for single 'String' value but there was more than a single value in the array");
				}
				return XssUtils.clean(parsed);
			}
			// [JACKSON-330]: need to gracefully handle byte[] data, as base64
			if (curr == JsonToken.VALUE_EMBEDDED_OBJECT) {
				Object ob = jp.getEmbeddedObject();
				if (ob == null) {
					return null;
				}
				if (ob instanceof byte[]) {
					return XssUtils.clean(Base64Variants.getDefaultVariant().encode((byte[]) ob, false));
				}
				// otherwise, try conversion using toString()...
				return XssUtils.clean(ob.toString());
			}
			// allow coercions for other scalar types
			String text = jp.getValueAsString();
			if (text != null) {
				return XssUtils.clean(text);
			}
			throw ctxt.mappingException(_valueClass, curr);
		}

		// Since we can never have type info ("natural type"; String, Boolean,
		// Integer, Double):
		// (is it an error to even call this version?)
		@Override
		public String deserializeWithType(JsonParser p, DeserializationContext ctxt, TypeDeserializer typeDeserializer)
				throws IOException {
			return deserialize(p, ctxt);
		}
	}
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