DuplicateTokenEx

The DuplicateTokenEx function creates a new access token that duplicates an existing token. This function can create either a primary token or an impersonation token.

BOOL DuplicateTokenEx(
  HANDLE hExistingToken,                           // handle to token to duplicate
  DWORD dwDesiredAccess,                           // access rights of new token
  LPSECURITY_ATTRIBUTES lpTokenAttributes,         // attributes
  SECURITY_IMPERSONATION_LEVEL ImpersonationLevel, // level
  TOKEN_TYPE TokenType,                            // primary or impersonation token
  PHANDLE phNewToken                               // handle to duplicated token
);

Parameters

hExistingToken

[in] Handle to an access token opened with TOKEN_DUPLICATE access.

dwDesiredAccess

[in] Specifies the requested access rights for the new token. The DuplicateTokenEx function compares the requested access rights with the existing token's discretionary access-control list (ACL) to determine which rights are granted or denied. To request the same access rights as the existing token, specify zero. To request all access rights that are valid for the caller, specify MAXIMUM_ALLOWED.

For a list of access rights for access tokens, see Access Rights for Access-Token Objects.

lpTokenAttributes

[in] Pointer to a SECURITY_ATTRIBUTES structure that specifies a security descriptor for the new token and determines whether child processes can inherit the token. If lpTokenAttributes is NULL, the token gets a default security descriptor and the handle cannot be inherited.

ImpersonationLevel

[in] Specifies a value from the SECURITY_IMPERSONATION_LEVEL enumeration that indicates the impersonation level of the new token.

TokenType

[in] Specifies one of the following values from the TOKEN_TYPE enumeration.

Value	Meaning
TokenPrimary	The new token is a primary token that you can use in the CreateProcessAsUser function.
TokenImpersonation	The new token is an impersonation token.

phNewToken

[out] Pointer to a HANDLE variable that receives the new token.

Return Values

If the function succeeds, the return value is a nonzero value.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

The DuplicateTokenEx function allows you to create a primary token that you can use in the CreateProcessAsUser function. This allows a server application that is impersonating a client to create a process that has the security context of the client. Note that the DuplicateToken function can create only impersonation tokens, which are not valid for CreateProcessAsUser.

The following is a typical scenario for using DuplicateTokenEx to create a primary token. A server application creates a thread that calls one of the impersonation functions, such as ImpersonateNamedPipeClient, to impersonate a client. The impersonating thread then calls the OpenThreadToken function to get its own token, which is an impersonation token that has the security context of the client. The thread specifies this impersonation token in a call to DuplicateTokenEx, specifying the TokenPrimary flag. DuplicateTokenEx creates a primary token that has the security context of the client.

When you have finished using the new token, call the CloseHandle function to close the token handle.

Requirements

  Windows NT/2000: Requires Windows NT 4.0 or later.
  Header: Declared in Winbase.h; include Windows.h.
  Library: Use Advapi32.lib.

See Also

Access Control Overview, Access Control Functions, CloseHandle, CreateProcessAsUser, DdeImpersonateClient, DuplicateToken, ImpersonateNamedPipeClient, OpenThreadToken, RevertToSelf, RpcImpersonateClient, SECURITY_ATTRIBUTES, SECURITY_IMPERSONATION_LEVEL