AccessCheck function (securitybaseapi.h)

Article
07/27/2022

The AccessCheck function determines whether a security descriptor grants a specified set of access rights to the client identified by an access token. Typically, server applications use this function to check access to a private object.

Syntax

BOOL AccessCheck(
  [in]            PSECURITY_DESCRIPTOR pSecurityDescriptor,
  [in]            HANDLE               ClientToken,
  [in]            DWORD                DesiredAccess,
  [in]            PGENERIC_MAPPING     GenericMapping,
  [out, optional] PPRIVILEGE_SET       PrivilegeSet,
  [in, out]       LPDWORD              PrivilegeSetLength,
  [out]           LPDWORD              GrantedAccess,
  [out]           LPBOOL               AccessStatus
);

Parameters

[in] pSecurityDescriptor

A pointer to a SECURITY_DESCRIPTOR structure against which access is checked.

[in] ClientToken

A handle to an impersonation token that represents the client that is attempting to gain access. The handle must have TOKEN_QUERY access to the token; otherwise, the function fails with ERROR_ACCESS_DENIED.

[in] DesiredAccess

Access mask that specifies the access rights to check. This mask must have been mapped by the MapGenericMask function to contain no generic access rights.

If this parameter is MAXIMUM_ALLOWED, the function sets the GrantedAccess access mask to indicate the maximum access rights the security descriptor allows the client.

[in] GenericMapping

A pointer to the GENERIC_MAPPING structure associated with the object for which access is being checked.

[out, optional] PrivilegeSet

A pointer to a PRIVILEGE_SET structure that receives the privileges used to perform the access validation. If no privileges were used, the function sets the PrivilegeCount member to zero.

[in, out] PrivilegeSetLength

Specifies the size, in bytes, of the buffer pointed to by the PrivilegeSet parameter.

[out] GrantedAccess

A pointer to an access mask that receives the granted access rights. If AccessStatus is set to FALSE, the function sets the access mask to zero. If the function fails, it does not set the access mask.

[out] AccessStatus

A pointer to a variable that receives the results of the access check. If the security descriptor allows the requested access rights to the client identified by the access token, AccessStatus is set to TRUE. Otherwise, AccessStatus is set to FALSE, and you can call GetLastError to get extended error information.

Return value

If the function succeeds, the return value is nonzero.

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

Remarks

For more information, see the How AccessCheck Works overview.

The AccessCheck function compares the specified security descriptor with the specified access token and indicates, in the AccessStatus parameter, whether access is granted or denied. If access is granted, the requested access mask becomes the object's granted access mask.

If the security descriptor's DACL is NULL, the AccessStatus parameter returns TRUE, which indicates that the client has the requested access.

The AccessCheck function fails with ERROR_INVALID_SECURITY_DESCR if the security descriptor does not contain owner and group SIDs.

The AccessCheck function does not generate an audit. If your application requires audits for access checks, use functions such as AccessCheckAndAuditAlarm, AccessCheckByTypeAndAuditAlarm, AccessCheckByTypeResultListAndAuditAlarm, or AccessCheckByTypeResultListAndAuditAlarmByHandle, instead of AccessCheck.

Examples

For an example that uses this function, see Verifying Client Access with ACLs.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	securitybaseapi.h (include Windows.h)
Library	Advapi32.lib
DLL	Advapi32.dll

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