在Global.asax文件里实现通用防SQL注入漏洞程序(适应于post/get请求)

首先，创建一个SQLInjectionHelper类完成恶意代码的检查
代码如下：

 
using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using System.Text.RegularExpressions; 
/// <summary> 
///SQLInjectionHelper 的摘要说明 
/// </summary> 
public class SQLInjectionHelper 
{ 
/// <summary> 
/// 获取Post的数据 
/// </summary> 
/// <param name="request"></param> 
/// <returns></returns> 
public static bool ValidUrlData(string request) 
{ 
bool result = false; 
if (request == "POST") 
{ 
for (int i = 0; i < HttpContext.Current.Request.Form.Count; i++) 
{ 
result = ValidData(HttpContext.Current.Request.Form[i].ToString()); 
if (result) 
{ 
break; 
} 
} 
} 
else 
{ 
for (int i = 0; i < HttpContext.Current.Request.QueryString.Count; i++) 
{ 
result = ValidData(HttpContext.Current.Request.QueryString[i].ToString()); 
if (result) 
{ 
break; 
} 
} 
} 
return result; 
} 
/// <summary> 
/// 验证是否存在注入代码 
/// </summary> 
/// <param name="inputData"></param> 
/// <returns></returns> 
private static bool ValidData(string inputData) 
{ 
//验证inputData是否包含恶意集合 
if (Regex.IsMatch(inputData, GetRegexString())) 
{ 
return true; 
} 
else 
{ 
return false; 
} 
} 
/// <summary> 
/// 获取正则表达式 
/// </summary> 
/// <returns></returns> 
private static string GetRegexString() 
{ 
//构造SQL的注入关键字符 
string[] strChar = { "and", "exec", "insert", "select", "update", "delete", "count", "from", "drop", "asc", "or", "char", "%", ";", ":", "\'", "\"", "-", "chr", "master", "mid", "truncate", "declare", "char", "SiteName", "/add", "xp_cmdshell", "net user", "net localgroup administrators", "exec master.dbo.xp_cmdshell" }; 
string str_Regex = ".*("; 
for (int i = 0; i < strChar.Length - 1; i++) 
{ 
str_Regex += strChar[i] + "|"; 
} 
str_Regex += strChar[strChar.Length - 1] + ").*"; 
return str_Regex; 
} 
} 

有此类后即可使用Global.asax中的Application_BeginRequest(object sender, EventArgs e)事件来实现表单或者URL提交数据的获取，获取后传给SQLInjectionHelper类ValidUrlData方法来完成检查
代码如下

复制代码代码如下:

 
protected void Application_BeginRequest(object sender, EventArgs e) 
{ 
bool result = false; 
result = SQLInjectionHelper.ValidUrlData(Request.RequestType.ToUpper()); 
if (result) 
{ 
Response.Write("您提交的数据有恶意字符"); 
Response.End(); 
} 
} 

下面以一个小程序测试：
创建一个页面，如下

复制代码代码如下:

 
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head runat="server"> 
<title></title> 
</head> 
<body> 
<form id="form1" runat="server"> 
<div> 
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> 
<br /> 
<asp:Button ID="btnPost" runat="server" Text="获取Post数据" 
onclick="btnPost_Click" /> 
</div> 
<asp:Button ID="btnGet" runat="server" Text="获取Get数据" onclick="btnGet_Click" /> 
</form> 
</body> 
</html> 

分别添加单击事件，如下

复制代码代码如下:

 
protected void btnPost_Click(object sender, EventArgs e) 
{ 
} 
protected void btnGet_Click(object sender, EventArgs e) 
{ 
Response.Redirect("Default.aspx?a=1&b=2&c=3"); 
} 

在文本框中输入非法字符串，无论post请求还是get请求，都会被防SQL注入程序所截获

图1 测试防SQL注入程序的页面

图2 错误信息

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