IServerSecurity::RevertToSelf method

Restores the authentication information of a thread to what it was before impersonation began.

Syntax

HRESULT RevertToSelf(

);

Parameters

This method has no parameters.

Return Value

If the method succeeds, the return value is S_OK. Otherwise, it is E_FAIL.

Remarks

RevertToSelf restores the authentication information on a thread to the authentication information on the thread before impersonation began. If the server does not call RevertToSelf before the end of the current call, it will be called automatically by COM.

When ImpersonateClient is called on a thread that is not currently impersonating, COM saves the token currently on the thread. A subsequent call to RevertToSelf restores the saved token, and IsImpersonating will then return FALSE. This means that if a series of impersonation calls are made using different IServerSecurity objects, RevertToSelf will restore the token that was on the thread when the first call to ImpersonateClient was made. Also, only one RevertToSelf call is needed to undo any number of ImpersonateClient calls.

This method will only revert impersonation changes made by ImpersonateClient. If the thread token is modified by other means (through the SetThreadToken or RpcImpersonateClient functions) the result of this function is undefined.

RevertToSelf affects only the current method invocation. If there are nested method invocations, each invocation can have its own impersonation token and DCOM will correctly restore the impersonation token before returning to them (regardless of whether CoRevertToSelf or RevertToSelf was called).

It is important to understand that an instance of IServerSecurity is valid on any thread in the apartment until the call represented by IServerSecurity completes. However, impersonation is local to a particular thread for the duration of the current call on that thread. Therefore, if two threads in the same apartment use the same IServerSecurity instance to call ImpersonateClient, one thread can call RevertToSelf without affecting the other.

Requirements

   
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header objidl.h (include ObjIdl.h)

See Also

CoRevertToSelf

IServerSecurity