SspiAcquireCredentialsHandleAsyncW function (sspi.h)
The SspiAcquireCredentialsHandleAsyncW function asynchronously acquires a handle to preexisting credentials of a security principal.
This handle is required by the SspiInitializeSecurityContextAsync and SspiAcceptSecurityContextAsync functions. These can be either preexisting credentials, which are established through a system logon that is not described here, or the caller can provide alternative credentials.
Note
This function serves as the asynchronous counterpart to AcquireCredentialsHandle.
Syntax
SECURITY_STATUS SspiAcquireCredentialsHandleAsyncW(
SspiAsyncContext *AsyncContext,
PSECURITY_STRING pszPrincipal,
PSECURITY_STRING pszPackage,
unsigned long fCredentialUse,
void *pvLogonId,
void *pAuthData,
SEC_GET_KEY_FN pGetKeyFn,
void *pvGetKeyArgument,
PCredHandle phCredential,
PTimeStamp ptsExpiry
);
Parameters
AsyncContext
The async call context.
pszPrincipal
A pointer to a null-terminated string that specifies the name of the principal whose credentials the handle will reference asynchronously.
Note
If the process that requests the handle does not have access to the credentials, the function returns an error. A null string indicates that the process requires a handle to the credentials of the user under whose security context it is executing.
pszPackage
A pointer to a null-terminated string that specifies the name of the security package with which these credentials will be used. This is a security package name returned in the Name member of a SecPkgInfo structure returned by the EnumerateSecurityPackages function. After a context is established, QueryContextAttributes (CredSSP) can be called with ulAttribute set to SECPKG_ATTR_PACKAGE_INFO to return information on the security package in use.
fCredentialUse
A flag that indicates how these credentials will be used. This parameter can be one of the following values:
Value |
Meaning |
|---|---|
| SECPKG_CRED_INBOUND | Validate an incoming server credential. Inbound credentials might be validated by using an authenticating authority when SspiInitializeSecurityContextAsync or SspiAcceptSecurityContextAsync is called. If such an authority is not available, the function will fail and return SEC_E_NO_AUTHENTICATING_AUTHORITY. Validation is package specific. |
| SECPKG_CRED_OUTBOUND | Allow a local client credential to prepare an outgoing token. |
pvLogonId
A pointer to a locally unique identifier (LUID) that identifies the user. This parameter is provided for file-system processes such as network redirectors. This parameter can be NULL.
pAuthData
A pointer to a CREDSSP_CRED structure that specifies authentication data for both Schannel and Negotiate packages.
pGetKeyFn
Pointer to the GetKey() function.
pvGetKeyArgument
Pass to GetKey().
phCredential
A pointer to the CredHandle structure that will receive the credential handle.
ptsExpiry
optional A pointer to a TimeStamp structure that receives the time at which the returned credentials expire. The structure value received depends on the security package, which must specify the value in local time.
Return value
Returns SEC_E_OK if the async request to acquire a credential handle was successfully queued for execution. Otherwise, it returns the error generated attempting to queue it. To retrieve the status of the operation, use SspiGetAsyncCallStatus.
If the handle was acquired, SspiGetAsyncCallStatus returns SEC_E_OK. Otherwise, it may return SEC_I_ASYNC_CALL_PENDING if the call is still in progress, or any of the following fatal error codes in the table below.
Return code |
Description |
|---|---|
| SEC_E_INSUFFICIENT_MEMORY | There is insufficient memory available to complete the requested action. |
| SEC_E_INTERNAL_ERROR | An error occurred that did not map to an SSPI error code. |
| SEC_E_NO_CREDENTIALS | No credentials are available in the security package |
| SEC_E_NOT_OWNER | The caller of the function does not have the necessary credentials. |
| SEC_E_SECPKG_NOT_FOUND | The requested security package does not exist. |
| SEC_E_UNKNOWN_CREDENTIALS | The credentials supplied to the package were not recognized. |
Remarks
The SspiAcquireCredentialsHandleAsyncW function returns a handle to the credentials of a principal, such as a user or client, as used by a specific security package. The function can return the handle to either preexisting credentials or newly created credentials and return it. This handle can be used in subsequent calls to the SspiAcceptSecurityContextAsync and SspiInitializeSecurityContextAsync functions.
In general, SspiAcquireCredentialsHandleAsyncW does not provide the credentials of other users logged on to the same computer. However, a caller with SE_TCB_NAME privilege can obtain the credentials of an existing logon session by specifying the logon identifier (LUID) of that session. Typically, this is used by kernel-mode modules that must act on behalf of a logged-on user.
A package might call the function in pGetKeyFn provided by the RPC run-time transport. If the transport does not support the notion of callback to retrieve credentials, this parameter must be NULL.
For kernel mode callers, the following differences must be noted:
- The two string parameters must be Unicode strings.
- The buffer values must be allocated in process virtual memory, not from the pool.
When you have finished using the returned credentials, free the memory used by the credentials by calling the SspiFreeCredentialsHandleAsync function.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 10, version 1607 [kernel-mode drivers only] |
| Minimum supported server | Windows Server 2016 [kernel-mode drivers only] |
| Header | sspi.h |
See also
SspiAcceptSecurityContextAsync
SspiFreeCredentialsHandleAsync