c# - AppDomain Evidence没有Zone？

Question

是什么在控制当前应用域的证据？

var evidence = Thread.GetDomain().Evidence;

什么控制它是空还是非空，什么决定它的内容？

当我的应用程序从域证据中查询这些宿主证据对象时

var z = evidence.GetHostEvidence<Zone> 
var p = evidence.GetHostEvidence<Publisher>
var s = evidence.GetHostEvidence<Site>
var n = evidence.GetHostEvidence<StrongName>
var u = evidence.GetHostEvidence<Url>

在某些环境下执行时，看起来好像有时它们都是空的。我认为这是在 IsolatedStorage._GetAccountingInfo(...) 中抛出的异常的原因，通过查看反射器中的代码，很明显只有域证据包含 null 时才会抛出此异常对于上述所有宿主证据对象。这将导致隔离存储无法初始化。

不幸的是，我无法在自己的系统上重现它。例如，Zone 值始终是表示“我的电脑”的正确值，所以我正在努力解决这个问题。

在 Windows 窗体桌面应用程序的默认应用程序域中，什么控制这些值的内容？

Answer 1

当您的代码是 COM object accessed by a native Win32 application 时，会出现类似的情况。 (默认 AppDomain 的 Evidence 是空的)，或者当它被加载并且 run inside of the command line version of PowerShell.exe .我在使用 OpenXML(特别是 EPPlus)程序集时遇到了这个问题，该程序集在办公文档超过特定文件大小时使用 IsolatedStorage。

与其在默认的 AppDomain 中启动另一个 AppDomain 并处理额外级别的 Marshaling/Remoting，我更喜欢使用反射来处理当前的 AppDomain的证据。

这是 C# 中的概念证明:

using System;

namespace AppDomainEvidence
{
    class Program
    {
        static void Main(string[] args)
        {
            var initialAppDomainEvidence = System.Threading.Thread.GetDomain().Evidence; // Setting a breakpoint here will let you inspect the current AppDomain's evidence
            try
            {
                var usfdAttempt1 = System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForDomain(); // This will fail when the current AppDomain Evidence is instantiated via COM or in PowerShell
            }
            catch (Exception e)
            {
                // Set breakpoint here to inspect Exception "e"
            }

            // Create a new Evidence that include the MyComputer zone
            var replacementEvidence = new System.Security.Policy.Evidence();
            replacementEvidence.AddHostEvidence(new System.Security.Policy.Zone(System.Security.SecurityZone.MyComputer));

            // Replace the current AppDomain's evidence using reflection
            var currentAppDomain = System.Threading.Thread.GetDomain();
            var securityIdentityField = currentAppDomain.GetType().GetField("_SecurityIdentity", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);
            securityIdentityField.SetValue(currentAppDomain,replacementEvidence);

            var latestAppDomainEvidence = System.Threading.Thread.GetDomain().Evidence; // Setting a breakpoint here will let you inspect the current AppDomain's evidence

            var usfdAttempt2 = System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForDomain(); // This should work
        }
    }
}

这是我在 PowerShell 中实现的解决方法:

# This one will fail
$usfd = [System.IO.IsolatedStorage.IsolatedStorageFile]::GetUserStoreForDomain()

# Inspect the current AppDomain's Evidence
[threading.thread]::GetDomain().Evidence


# Modify the current AppDomain's Evidence
$evidence = new-object System.Security.Policy.Evidence
$zone = new-object System.Security.Policy.Zone('MyComputer')
$evidence.AddHost($zone)
$currentAppDomain = [threading.thread]::GetDomain()
$securityIdentityField=$currentAppDomain.GetType().GetField('_SecurityIdentity','Instance,NonPublic')
$securityIdentityField.SetValue($currentAppDomain, $evidence)

# Inspect the current AppDomain's Evidence
[threading.thread]::GetDomain().Evidence

# This one will succeed
$usfd = [System.IO.IsolatedStorage.IsolatedStorageFile]::GetUserStoreForDomain()