ASP.NET应用程序中使用身份模拟(Impersonation)
2010-10-19 13:42:16 来源:WEB开发网核心提示:Visual C# .NET<%@ Page Language="C#"%><%@ Import Namespace = "System.Web" %><%@ Import Namespace = "System.Web.Security&
Visual C# .NET
<%@ Page Language="C#"%> <%@ Import Namespace = "System.Web" %> <%@ Import Namespace = "System.Web.Security" %> <%@ Import Namespace = "System.Security.Principal" %> <%@ Import Namespace = "System.Runtime.InteropServices" %> <script runat=server> public const int LOGON32_LOGON_INTERACTIVE = 2; public const int LOGON32_PROVIDER_DEFAULT = 0; WindowsImpersonationContext impersonationContext; [DllImport("advapi32.dll", CharSet=CharSet.Auto)] public static extern int LogonUser(String lpszUserName, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken); [DllImport("advapi32.dll", CharSet=System.Runtime.InteropServices.CharSet.Auto, SetLastError=true)] public extern static int DuplicateToken(IntPtr hToken, int impersonationLevel, ref IntPtr hNewToken); public void Page_Load(Object s, EventArgs e) { if(impersonateValidUser("username", "domain", "password")) { //Insert your code that runs under the security context of a specific user here. undoImpersonation(); } else { //Your impersonation failed. Therefore, include a fail-safe mechanism here. } } private bool impersonateValidUser(String userName, String domain, String password) { WindowsIdentity tempWindowsIdentity; IntPtr token = IntPtr.Zero; IntPtr tokenDuplicate = IntPtr.Zero; if(LogonUser(userName, domain, password, LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, ref token) != 0) { if(DuplicateToken(token, 2, ref tokenDuplicate) != 0) { tempWindowsIdentity = new WindowsIdentity(tokenDuplicate); impersonationContext = tempWindowsIdentity.Impersonate(); if (impersonationContext != null) return true; else return false; } else return false; } else return false; } private void undoImpersonation() { impersonationContext.Undo(); } </script>
下面介绍ASP.NET应用程序中使用身份模拟的一个简单应用。例如有一个ASP.NET应用程序要检查服务器端某个文件是否存在,相应的程序代码为:
bool a = File.Exists("D:\\Share\\test.txt");
缺省情况下该ASP.NET应用程序以ASPNET帐号运行。为了安全起见,ASPNET这个帐号并没有服务器端D:\Share\这个目录的访问权限。在不使用身份模拟的情况下,由于ASP.NET应用程序不具有访问该目录的权限,无论文件是否存在,File.Exists的返回值将永远是false。为了解决这个问题,可以另建一个用户帐号:FileExist,并赋予该帐号D:\Share\目录的访问权限。然后在该应用程序的Web.config文件的<identity>标记中指定具体的用户帐号:
<identity impersonate="true" userName="FileExist" password="password" />
来执行该程序。
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