如何防止SQL注入问题

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本文转自juejin.cn/post/685992…

1. 代码层防止sql注入攻击的最佳方案就是sql预编译

public List<Course> orderList(String studentId){
    String sql = "select id,course_id,student_id,status from course where student_id = ?";
    return jdbcTemplate.query(sql,new Object[]{studentId},new BeanPropertyRowMapper(Course.class));
}
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2. 确认每种数据的类型,比如是数字,数据库则必须使用int类型来存储

3. 规定数据长度,能在一定程度上防止sql注入

4. 严格限制数据库权限,能最大程度减少sql注入的危害

5. 避免直接响应一些sql异常信息,sql发生异常后,自定义异常进行响应

6. 在过滤器中过滤参数中含有的一些数据库关键词

@Component public class SqlInjectionFilter implements Filter { @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain) throws IOException, ServletException { HttpServletRequest req=(HttpServletRequest)servletRequest; HttpServletRequest res=(HttpServletRequest)servletResponse; //获得所有请求参数名 Enumeration params = req.getParameterNames(); String sql = ""; while (params.hasMoreElements()) { // 得到参数名 String name = params.nextElement().toString(); // 得到参数对应值 String[] value = req.getParameterValues(name); for (int i = 0; i < value.length; i++) { sql = sql + value[i]; } } if (sqlValidate(sql)) { throw new IOException("您发送请求中的参数中含有非法字符"); } else { chain.doFilter(servletRequest,servletResponse); } } /** * 关键词校验 * @param str * @return / protected static boolean sqlValidate(String str) { // 统一转为小写 str = str.toLowerCase(); // 过滤掉的sql关键字,可以手动添加 String badStr = "'|and|exec|execute|insert|select|delete|update|count|drop||%|chr|mid|master|truncate|" + "char|declare|sitename|net user|xp_cmdshell|;|or|-|+|,|like'|and|exec|execute|insert|create|drop|" + "table|from|grant|use|group_concat|column_name|" + "information_schema.columns|table_schema|union|where|select|delete|update|order|by|count|*|" + "chr|mid|master|truncate|char|declare|or|;|-|--|+|,|like|//|/|%|#"; String[] badStrs = badStr.split("\|"); for (int i = 0; i < badStrs.length; i++) { if (str.indexOf(badStrs[i]) >= 0) { return true; } } return false; } }