我的网站上有以下代码。它将 URL 查询作为名为 commandencrypted 的字符串。我有一个 try/catch/finally 块,它将加密的命令复制到内存流,然后将其解密回字符串。如果 try 块中出现任何错误,它们将在 catch 块中处理。但是,我想确保在 finally 块中关闭所有使用的资源。当提供无效的 URL 查询命令时,我在尝试关闭 csencryptedcommand CryptoStream 时收到异常。异常详细信息遵循代码。
// Resources used for storing and decrypting the encrypted client command
MemoryStream msencryptedcommand = null;
RijndaelManaged rmencryptedcommand = null;
CryptoStream csencryptedcommand = null;
StreamReader srdecryptedcommand = null;
MemoryStream msdecryptedcommand = null;
try
{
// Copy the encrypted client command (where two characters represent a byte) to a memorystream
msencryptedcommand = new MemoryStream();
for (int i = 0; i < encryptedcommand.Length; )
{
msencryptedcommand.WriteByte(Byte.Parse(encryptedcommand.Substring(i, 2), NumberStyles.HexNumber));
i = i + 2;
}
msencryptedcommand.Flush();
msencryptedcommand.Position = 0;
// Define parameters used for decryption
byte[] key = new byte[] { //bytes hidden// };
byte[] iv = new byte[] { //bytes hidden// };
rmencryptedcommand = new RijndaelManaged();
csencryptedcommand = new CryptoStream(msencryptedcommand, rmencryptedcommand.CreateDecryptor(key, iv), CryptoStreamMode.Read);
msdecryptedcommand = new MemoryStream();
// Decrypt the client command
int decrytptedbyte;
while ((decrytptedbyte = csencryptedcommand.ReadByte()) != -1)
{
msdecryptedcommand.WriteByte((byte)decrytptedbyte);
}
// Store the decrypted client command as a string
srdecryptedcommand = new StreamReader(msdecryptedcommand);
srdecryptedcommand.BaseStream.Position = 0;
string decryptedcommand = srdecryptedcommand.ReadToEnd();
}
catch (Exception ex)
{
ErrorResponse("Invalid URL Query", context, ex.ToString());
return;
}
finally
{
// If any resources were used, close or clear them
if (srdecryptedcommand != null)
{
srdecryptedcommand.Close();
}
if (msdecryptedcommand != null)
{
msdecryptedcommand.Close();
}
if (csencryptedcommand != null)
{
csencryptedcommand.Close();
}
if (rmencryptedcommand != null)
{
rmencryptedcommand.Clear();
}
if (msencryptedcommand != null)
{
msencryptedcommand.Close();
}
}
发生以下未处理的异常:System.Security.Cryptography.CryptographicException:要解密的数据长度无效。在 System.Security.Cryptography.RijndaelManagedTransform.TransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount) 在 System.Security.Cryptography.CryptoStream.FlushFinalBlock() 在 System.Security.Cryptography.CryptoStream.Dispose(Boolean disposing) 在 System update.ashx 中 dongleupdate.ProcessRequest(HttpContext context) 处的 .IO.Stream.Close():System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() 处 System.Web.HttpApplication 的第 92 行。 ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) URL Referrer: User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/30.0.1599.69 Safari/537。
编辑:
我将代码更改为使用 using 语句。这也是确保关闭所有资源的有效方法吗?
try
{
// Copy the encrypted client command (where two characters represent a byte) to a memorystream
using (MemoryStream msencryptedcommand = new MemoryStream())
{
for (int i = 0; i < encryptedcommand.Length; )
{
msencryptedcommand.WriteByte(Byte.Parse(encryptedcommand.Substring(i, 2), NumberStyles.HexNumber));
i = i + 2;
}
msencryptedcommand.Flush();
msencryptedcommand.Position = 0;
// Define parameters used for decryption
byte[] key = new byte[] { //bytes hidden// };
byte[] iv = new byte[] { //bytes hidden// };
using (RijndaelManaged rmencryptedcommand = new RijndaelManaged())
{
using (CryptoStream csencryptedcommand = new CryptoStream(msencryptedcommand, rmencryptedcommand.CreateDecryptor(key, iv), CryptoStreamMode.Read))
{
using (MemoryStream msdecryptedcommand = new MemoryStream())
{
// Decrypt the client command
int decrytptedbyte;
while ((decrytptedbyte = csencryptedcommand.ReadByte()) != -1)
{
msdecryptedcommand.WriteByte((byte)decrytptedbyte);
}
// Store the decrypted client command as a string
using (StreamReader srdecryptedcommand = new StreamReader(msdecryptedcommand))
{
srdecryptedcommand.BaseStream.Position = 0;
string decryptedcommand = srdecryptedcommand.ReadToEnd();
}
}
}
}
}
}
catch (Exception ex)
{
ErrorResponse("Invalid URL Query", context, ex.ToString());
return;
}