/// <summary>
/// Retrieves credentials for the specified target from the operating system's credential store for the current user.
/// </summary>
/// <param name="target">The target name for the credentials.</param>
/// <returns>The credentials if they were found; otherwise, <see langword="null" />.</returns>
/// <remarks>
/// <para>
/// If the requested credential was not originally stored using the <see cref="CredentialDialog"/> class (but e.g. by
/// another application), the password may not be decoded correctly.
/// </para>
/// <para>
/// This function does not check the application instance credential cache for the credentials; for that you can use
/// the <see cref="RetrieveCredentialFromApplicationInstanceCache"/> function.
/// </para>
/// </remarks>
/// <exception cref="ArgumentNullException"><paramref name="target"/> is <see langword="null" />.</exception>
/// <exception cref="ArgumentException"><paramref name="target"/> is an empty string ("").</exception>
/// <exception cref="CredentialException">An error occurred retrieving the credentials.</exception>
public static NetworkCredential RetrieveCredential(string target)
{
if (target == null)
{
throw new ArgumentNullException("target");
}
if (target.Length == 0)
{
throw new ArgumentException(Properties.Resources.CredentialEmptyTargetError, "target");
}
NetworkCredential cred = RetrieveCredentialFromApplicationInstanceCache(target);
if (cred != null)
{
return(cred);
}
IntPtr credential;
bool result = NativeMethods.CredRead(target, NativeMethods.CredTypes.CRED_TYPE_GENERIC, 0, out credential);
int error = System.Runtime.InteropServices.Marshal.GetLastWin32Error();
if (result)
{
try
{
NativeMethods.CREDENTIAL c = (NativeMethods.CREDENTIAL)System.Runtime.InteropServices.Marshal.PtrToStructure(credential, typeof(NativeMethods.CREDENTIAL));
byte[] encryptedPassword = new byte[c.CredentialBlobSize];
System.Runtime.InteropServices.Marshal.Copy(c.CredentialBlob, encryptedPassword, 0, encryptedPassword.Length);
cred = new NetworkCredential(c.UserName, DecryptPassword(encryptedPassword));
}
finally
{
NativeMethods.CredFree(credential);
}
return(cred);
}
else
{
if (error == (int)NativeMethods.CredUIReturnCodes.ERROR_NOT_FOUND)
{
return(null);
}
else
{
throw new CredentialException(error);
}
}
}
/// <summary>
/// Stores the specified credentials in the operating system's credential store for the currently logged on user.
/// </summary>
/// <param name="target">The target name for the credentials.</param>
/// <param name="credential">The credentials to store.</param>
/// <exception cref="ArgumentNullException">
/// <para>
/// <paramref name="target"/> is <see langword="null" />.
/// </para>
/// <para>
/// -or-
/// </para>
/// <para>
/// <paramref name="credential"/> is <see langword="null" />.
/// </para>
/// </exception>
/// <exception cref="ArgumentException"><paramref name="target"/> is an empty string ("").</exception>
/// <exception cref="CredentialException">An error occurred storing the credentials.</exception>
/// <remarks>
/// <note>
/// The <see cref="NetworkCredential.Domain"/> property is ignored and will not be stored, even if it is
/// not <see langword="null" />.
/// </note>
/// <para>
/// If the credential manager already contains credentials for the specified <paramref name="target"/>, they
/// will be overwritten; this can even overwrite credentials that were stored by another application. Therefore
/// it is strongly recommended that you prefix the target name to ensure uniqueness, e.g. using the
/// form "Company_ApplicationName_www.example.com".
/// </para>
/// </remarks>
public static void StoreCredential(string target, NetworkCredential credential)
{
if (target == null)
{
throw new ArgumentNullException("target");
}
if (target.Length == 0)
{
throw new ArgumentException(Properties.Resources.CredentialEmptyTargetError, "target");
}
if (credential == null)
{
throw new ArgumentNullException("credential");
}
NativeMethods.CREDENTIAL c = new NativeMethods.CREDENTIAL();
c.UserName = credential.UserName;
c.TargetName = target;
c.Persist = NativeMethods.CredPersist.Enterprise;
byte[] encryptedPassword = EncryptPassword(credential.Password);
c.CredentialBlob = System.Runtime.InteropServices.Marshal.AllocHGlobal(encryptedPassword.Length);
try
{
System.Runtime.InteropServices.Marshal.Copy(encryptedPassword, 0, c.CredentialBlob, encryptedPassword.Length);
c.CredentialBlobSize = (uint)encryptedPassword.Length;
c.Type = NativeMethods.CredTypes.CRED_TYPE_GENERIC;
if (!NativeMethods.CredWrite(ref c, 0))
{
throw new CredentialException(System.Runtime.InteropServices.Marshal.GetLastWin32Error());
}
}
finally
{
System.Runtime.InteropServices.Marshal.FreeCoTaskMem(c.CredentialBlob);
}
}