防注入组件的编写 (asp.net C#)

     经常要写一些.net的程序，对于数据库的防注入要求要比较高。这时我从网上搜了一些代码。查看了一下主要是通过HTTPModel来进行对客户端转过来的数据进行处理。
       在服务器安全栏目里我写过一篇《破解通用Sql防注入方法》的文章中说到，一些通用的防注入方法中没有对cookie数据进行过滤，会给黑客留下可乘之机。当然我的这段代码对提交过来的cookie数据也进行了过滤。

代码：

using System;
using System.Configuration;
using System.Web;
using System.Globalization;
namespace JNYW.StuM.SqlInject
{
    public class SqlstrAny : IHttpModule
    {       
        public void Init(HttpApplication application)
        {
            application.BeginRequest += (new
            EventHandler(this.Application_BeginRequest));
        }
        private void Application_BeginRequest(Object source, EventArgs e)
        {          
            ProcessRequest pr = new ProcessRequest();
            pr.StartProcessRequest();
        }
        public void Dispose()
        {
        }
     }

     public class ProcessRequest
     {
         private static string SqlStr = System.Configuration.ConfigurationManager.AppSettings["SqlInject"].ToString();
         private static string sqlErrorPage = System.Configuration.ConfigurationSettings.AppSettings["SQLInjectErrPage"].ToString();
         ///
         /// 用来识别是否是流的方式传输
         ///
         ///
         ///
         bool IsUploadRequest(HttpRequest request)
         {
             return StringStartsWithAnotherIgnoreCase(request.ContentType, "multipart/form-data");
         }
         ///
         /// 比较内容类型
         ///
         ///
         ///
         ///
         private static bool StringStartsWithAnotherIgnoreCase(string s1, string s2)
         {
             return (string.Compare(s1, 0, s2, 0, s2.Length, true, CultureInfo.InvariantCulture) == 0);
         }
        
        //SQL注入式攻击代码分析
         #region SQL注入式攻击代码分析
         ///
         /// 处理用户提交的请求
         ///
         public void StartProcessRequest()
         {
             HttpRequest Request = System.Web.HttpContext.Current.Request;
             HttpResponse Response = System.Web.HttpContext.Current.Response;
             try
             {
                 string getkeys = "";
                 if (IsUploadRequest(Request)) return; //如果是流传递就退出
                 //字符串参数
                 if (Request.QueryString != null)
                 {
                     for (int i = 0; i < Request.QueryString.Count; i++)
                     {
                         getkeys = Request.QueryString.Keys[i];
                         if (!ProcessSqlStr(Request.QueryString[getkeys]))
                         {
                             Response.Redirect(sqlErrorPage + "?errmsg=QueryString中含有非法字符串&sqlprocess=true");
                             Response.End();
                         }
                     }
                 }
                 //form参数
                 if (Request.Form != null)
                 {
                     for (int i = 0; i < Request.Form.Count; i++)
                     {
                         getkeys = Request.Form.Keys[i];
                         if (!ProcessSqlStr(Request.Form[getkeys]))
                         {
                             Response.Redirect(sqlErrorPage + "?errmsg=Form中含有非法字符串&sqlprocess=true");
                             Response.End();
                         }
                     }
                 }
                 //cookie参数
                 if (Request.Cookies != null)
                 {
                     for (int i = 0; i < Request.Cookies.Count; i++)
                     {
                         getkeys = Request.Cookies.Keys[i];
                         if (!ProcessSqlStr(Request.Cookies[getkeys].Value))
                         {
                             Response.Redirect(sqlErrorPage + "?errmsg=Cookie中含有非法字符串&sqlprocess=true");
                             Response.End();
                         }
                     }
                 }
             }
             catch
             {
                 // 错误处理: 处理用户提交信息!
                 Response.Clear();
                 Response.Write("CustomErrorPage配置错误");
                 Response.End();
             }
         }
          
         ///
         /// 分析用户请求是否正常
         ///
         /// 传入用户提交数据
         /// 返回是否含有SQL注入式攻击代码
         private bool ProcessSqlStr(string Str)
         {
             bool ReturnValue = true;
             try
             {
                 if (Str != "")
                 {
                     string[] anySqlStr = SqlStr.Split('|');
                     foreach (string ss in anySqlStr)
                     {
                         if (Str.IndexOf(ss) >= 0)
                         {
                             ReturnValue = false;
                             break;
                         }
                     }
                 }
             }
             catch
             {
                 ReturnValue = false;
             }
             return ReturnValue;
         }
         #endregion
     }
}

在实际使用时，我们要在Web.config文件中的配置节中加上下面的代码

以下是示例代码：

    <!--防注入设置-->
    <add value="and |exec |insert |select |delete |update |count | * |chr |mid |master |truncate |char |declare " key="SQLInject" />
    <add value="ShowErr.aspx" key="SQLInjectErrPage" />

并且在Web.Config文件的<SYSTEM.WEB>中再加上下面的代码。 以下是示例代码：

      <!--防注入设置-->
      <HTTPMODULES>
           <aDD name="SqlstrAny" type="JNYW.StuM.SqlInject.SqlstrAny,SqlstrAny" />
      </HTTPMODULES>