Springboot詳解如何實現(xiàn)SQL注入過濾器過程

更新時間：2022年06月17日 10:36:40 作者：zhangbeizhen18

這篇文章主要介紹了基于springboot實現(xiàn)SQL注入過濾器，具有很好的參考價值，希望對大家有所幫助。一起跟隨小編過來看看吧

場景：以過濾器(Filter)的方式，對所有http請求的入參攔截，使用正則表達式匹配入參中的字符串。存在SQL注入風險的參數，中斷請求，并立即返回提示信息。不存在SQL注入風險的參數，校驗通過后，放入過濾器鏈，繼續(xù)后續(xù)業(yè)務。

環(huán)境：本例是基于springboot的web工程，版本：springboot 2.6.3

1.過濾器SqlInjectFilter

SqlInjectFilter，實現(xiàn)javax.servlet.Filter接口。即在doFilter方法中實現(xiàn)具體邏輯。

@Slf4j
public class SqlInjectFilter implements Filter {
  private static final String SQL_REG_EXP = ".*(\\b(select|insert|into|update|delete|from|where|and|or|trancate" +
      "|drop|execute|like|grant|use|union|order|by)\\b).*";
  @Override
  public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) servletRequest;
    CustomRequestWrapper requestWrapper = new CustomRequestWrapper(request);
    Map<String, Object> parameterMap = new HashMap<>();
    parameterMap =getParameterMap(parameterMap, request, requestWrapper);
    // 正則校驗是否有SQL關鍵字
    for (Object obj : parameterMap.entrySet()) {
        Map.Entry entry = (Map.Entry) obj;
        Object value = entry.getValue();
        if (value != null) {
            boolean isValid = isSqlInject(value.toString(), servletResponse);
            if (!isValid) {
                return;
            }
        }
    }
    filterChain.doFilter(requestWrapper, servletResponse);
  }
  private Map<String, Object> getParameterMap(Map<String, Object> paramMap, HttpServletRequest request, CustomRequestWrapper requestWrapper) {
    // 1.POST請求獲取參數
    if ("POST".equals(request.getMethod().toUpperCase())) {
        String body = requestWrapper.getBody();
        paramMap = JSONObject.parseObject(body, HashMap.class);
    } else {
        Map<String, String[]> parameterMap = requestWrapper.getParameterMap();
        //普通的GET請求
        if (parameterMap != null && parameterMap.size() > 0) {
            Set<Map.Entry<String, String[]>> entries = parameterMap.entrySet();
            for (Map.Entry<String, String[]> next : entries) {
                paramMap.put(next.getKey(), next.getValue()[0]);
            }
        } else {
            //GET請求,參數在URL路徑型式,比如server/{var1}/{var2}
            String afterDecodeUrl = null;
            try {
                //編碼過URL需解碼解碼還原字符
                afterDecodeUrl = URLDecoder.decode(request.getRequestURI(), "UTF-8");
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            paramMap.put("pathVar", afterDecodeUrl);
        }
    }
    return paramMap;
  }
  private boolean isSqlInject(String value, ServletResponse servletResponse) throws IOException {
    if (null != value && value.toLowerCase().matches(SQL_REG_EXP)) {
      log.info("入參中有非法字符: " + value);
      HttpServletResponse response = (HttpServletResponse) servletResponse;
      Map<String, String> responseMap = new HashMap<>();
      // 匹配到非法字符,立即返回
      responseMap.put("code", "999");
      responseMap.put("message","入參中有非法字符");
      response.setContentType("application/json;charset=UTF-8");
      response.setStatus(HttpStatus.OK.value());
      response.getWriter().write(JSON.toJSONString(responseMap));
      response.getWriter().flush();
      response.getWriter().close();
      return false;
    }
    return true;
  }
}

2.請求裝飾類CustomRequestWrapper

在攔截請求時，會讀取HttpServletRequest的InputStream，而這種數據流一旦讀取后，就沒了。那么直接把請求放入過濾器鏈，后續(xù)的環(huán)節(jié)就讀取不到數據了。因此，需要一個裝飾類，讀取了InputStream數據后，還得回寫到請求中。然后把數據完整的裝飾類放入過濾器鏈。這樣攔截了請求，讀取了數據，并回寫了數據，數據完整性得到保證。

public class CustomRequestWrapper extends HttpServletRequestWrapper {
  private final String body;
  public CustomRequestWrapper(HttpServletRequest request) throws IOException {
    super(request);
    StringBuilder sb = new StringBuilder();
    BufferedReader bufferedReader = null;
    try {
      InputStream inputStream = request.getInputStream();
      if (inputStream != null) {
          bufferedReader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
          char[] charBuffer = new char[512];
          int bytesRead = -1;
          while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
              sb.append(charBuffer, 0, bytesRead);
          }
      } else {
          sb.append("");
      }
    } catch (IOException e) {
      e.printStackTrace();
      throw e;
    } finally {
      if (bufferedReader != null) {
      try {
          bufferedReader.close();
      } catch (IOException e) {
          e.printStackTrace();
          throw e;
      }
      }
    }
    body = sb.toString();
  }
  @Override
  public ServletInputStream getInputStream() throws IOException {
    final ByteArrayInputStream bais = new ByteArrayInputStream(body.getBytes("UTF-8"));
    return new ServletInputStream() {
      @Override
      public boolean isFinished() {
          return false;
      }
      @Override
      public boolean isReady() {
          return false;
      }
      @Override
      public void setReadListener(ReadListener readListener) {
      }
      @Override
      public int read() {
          return bais.read();
      }
    };
  }
  @Override
  public BufferedReader getReader() throws IOException {
    return new BufferedReader(new InputStreamReader(this.getInputStream(), StandardCharsets.UTF_8));
  }
  public String getBody() {
    return this.body;
  }
  @Override
  public String getParameter(String name) {
    return super.getParameter(name);
  }
  @Override
  public Map<String, String[]> getParameterMap() {
    return super.getParameterMap();
  }
  @Override
  public Enumeration<String> getParameterNames() {
    return super.getParameterNames();
  }
  @Override
  public String[] getParameterValues(String name) {
    return super.getParameterValues(name);
  }
}

3.過濾器注冊

過濾器生效，需注冊。

@Configuration
public class FilterConfiguration {
  @Bean("sqlFilter")
  public SqlInjectFilter sqlInjectFilter() {
    return new SqlInjectFilter();
  }
  @Bean
  public FilterRegistrationBean<SqlInjectFilter> sqlFilterRegistrationBean() {
    FilterRegistrationBean<SqlInjectFilter> filterReg = new FilterRegistrationBean<>();
    filterReg.setFilter(sqlInjectFilter());
    filterReg.addUrlPatterns("/*");
    filterReg.setOrder(1);
    return filterReg;
  }
}

4.測試輔助類

4.1 結果對象ResultObj

Restful請求返回格式統(tǒng)一。

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class ResultObj {
    private String code;
    private String message;
}

4.2 Restful的Controller類

SqlInjectionController，包括POST請求和GET請求測試。

@RestController
@Slf4j
@RequestMapping("/inject")
public class SqlInjectionController {
  @PostMapping("/f1")
  public Object f1(@RequestBody Object obj) {
    log.info("SqlInjectionController->f1,接收參數,obj = " + obj.toString());
    log.info("SqlInjectionController->f1,返回.");
    return ResultObj.builder().code("200").message("成功").build();
  }
  @GetMapping("/f2")
  public Object f2(@RequestParam(name = "var") String var) {
    log.info("SqlInjectionController->f2,接收參數,var = " + var);
    log.info("SqlInjectionController->f2,返回.");
    return ResultObj.builder().code("200").message("成功").build();
  }
  @GetMapping("/f3/{var}")
  public Object f3(@PathVariable("var") String var) {
    log.info("SqlInjectionController->f3,接收參數,var = " + var);
    log.info("SqlInjectionController->f3,返回.");
    return ResultObj.builder().code("200").message("成功").build();
  }
}