用于XSS保护的请求体处的Spring Boot转义字符

Question

我正在尝试使用XSSFilter保护我的spring boot应用程序，如下所示：

public class XSSFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException { }

    @Override
    public void destroy() { }

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

}

包装：

public class XSSRequestWrapper extends HttpServletRequestWrapper {

    public XSSRequestWrapper(HttpServletRequest servletRequest) {
        super(servletRequest);
    }

    @Override
    public String[] getParameterValues(String parameter) {
        String[] values = super.getParameterValues(parameter);

        if (values == null) {
            return null;
        }

        int count = values.length;
        String[] encodedValues = new String[count];
        for (int i = 0; i < count; i++) {
            encodedValues[i] = replaceXSSCharacters((values[i]));
        }

        return encodedValues;
    }

    private String replaceXSSCharacters(String value) {
        if (value == null) {
            return null;
        }

        return value
                .replace("&","&#38;")
                .replace("<", "&#60;")
                .replace(">","&#62;")
                .replace("\"","&#34;")
                .replace("'","&#39;");
    }

    @Override
    public String getParameter(String parameter) {
        return replaceXSSCharacters(super.getParameter(parameter));
    }

    @Override
    public String getHeader(String name) {
        return replaceXSSCharacters(super.getHeader(name));
    }

}

问题是，这只保护请求参数和标头，而不是请求主体，有时我的控制器使用@刚体接收数据。

因此，如果我向控制器提交一个json，如下所示：

{"name":"<script>alert('hello!')</script>"}

name属性的html字符没有像我需要的那样被转义。我怎样才能逃出尸体？

编辑：这与“重复”问题不同。我的问题很具体。如何在请求正文中转义字符。

Answer 1

要删除XSS字符，您只需覆盖AbstractJackson2HttpMessageConverter—此转换器负责读取请求。请求主体对象的inputStream

@Component
public class XSSRequestBodyConverter extends AbstractJackson2HttpMessageConverter {
    public XSSRequestBodyConverter(ObjectMapper objectMapper) {
        super(objectMapper, MediaType.APPLICATION_JSON, new MediaType("application", "*+json"));
    }

@Override
public Object read(Type type, Class<?> contextClass, HttpInputMessage inputMessage)
        throws IOException, HttpMessageNotReadableException {

    Object requestBody = super.read(type, contextClass, inputMessage);
    //Remove xss from requestBody here
    String requestInStr = objectMapper.writeValueAsString(requestBody);
    return objectMapper.readValue(replaceXSSCharacters(requestInStr), Object.class);
}


}

Answer 2

1. 在XSSRequestWrapper中有一个本地字符串字段，用于保存已清理的实体（可能不适用于大型实体）

当JSON被反序列化为Java对象时，您可能还对清理JSON感兴趣。

Answer 3

我使用自定义类解决了以下问题：

@Configuration
public class AntiXSSConfig  {

    @Autowired()
    public void configeJackson(ObjectMapper mapper) {
        mapper.getFactory().setCharacterEscapes(new HTMLCharacterEscapes());
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    }

    public static class HTMLCharacterEscapes extends JsonpCharacterEscapes {

        @Override
        public int[] getEscapeCodesForAscii() {
            int[] asciiEscapes = CharacterEscapes.standardAsciiEscapesForJSON();
            // and force escaping of a few others:
            asciiEscapes['<'] = CharacterEscapes.ESCAPE_CUSTOM;
            asciiEscapes['>'] = CharacterEscapes.ESCAPE_CUSTOM;
            asciiEscapes['&'] = CharacterEscapes.ESCAPE_CUSTOM;
            asciiEscapes['"'] = CharacterEscapes.ESCAPE_CUSTOM;
            asciiEscapes['\''] = CharacterEscapes.ESCAPE_CUSTOM;
            return asciiEscapes;
        }

        @Override
        public SerializableString getEscapeSequence(int ch) {
            switch (ch) {
                case '&' : return new SerializedString("&#38;");
                case '<' : return new SerializedString("&#60;");
                case '>' : return new SerializedString("&#62;");
                case '\"' : return new SerializedString("&#34;");
                case '\'' : return new SerializedString("&#39;");
                default : return super.getEscapeSequence(ch);
            }
        }
    }
}

它涵盖了所有的案例。