Platform SDK: Access Control

SetEntriesInAcl

The SetEntriesInAcl function creates a new access-control list (ACL) by merging new access-control or audit-control information into an existing ACL.

DWORD SetEntriesInAcl(
  ULONG cCountOfExplicitEntries,           // number of entries
  PEXPLICIT_ACCESS pListOfExplicitEntries, // buffer
  PACL OldAcl,                             // original ACL
  PACL *NewAcl                             // new ACL
);

Parameters

cCountOfExplicitEntries: [in] Specifies the number of EXPLICIT_ACCESS structures in the pListOfExplicitEntries array.
pListOfExplicitEntries: [in] Pointer to an array of EXPLICIT_ACCESS structures that describe the access control information to merge into the existing ACL.
OldAcl: [in] Pointer to the existing ACL. This parameter can be NULL, in which case, the function creates a new ACL based on the EXPLICIT_ACCESS entries.
NewAcl: [out] Pointer to a variable that receives a pointer to the new ACL. If the function succeeds, you must call the LocalFree function to free the returned buffer.

Return Values

If the function succeeds, the return value is ERROR_SUCCESS.

If the function fails, the return value is a nonzero error code defined in Winerror.h.

Remarks

Each entry in the array of EXPLICIT_ACCESS structures specifies access-control or audit-control information for a specified trustee. A trustee can be a user, group, or other SID value, such as a logon identifier or logon type (for instance, a Win32 service or batch job). You can use a name or a security identifier (SID) to identify a trustee.

You can use the SetEntriesInAcl function to modify the list of ACEs in a DACL or a SACL. A DACL controls access to an object, and a SACL controls the system's auditing of attempts to access to an object. Note that SetEntriesInAcl does not prevent you from mixing access-control and audit-control information in the same ACL; however, the resulting ACL will contain meaningless entries.

For a DACL, the grfAccessMode member of the EXPLICIT_ACCESS structure specifies whether to allow, deny, or revoke access rights for the trustee. This member can specify one of the following values from the ACCESS_MODE enumeration.

Value	Meaning
GRANT_ACCESS	Creates a new access-allowed ACE that combines the specified rights with any existing rights of the trustee. The new ACE replaces any existing access-allowed ACE for the trustee. The function also modifies or deletes any existing access-denied ACE for the trustee that denies the specified rights.
SET_ACCESS	Similar to GRANT_ACCESS except that the new access-allowed ACE allows only the specified rights, discarding any existing rights. This flag also removes any existing access-denied ACE for the trustee.
DENY_ACCESS	Creates a new access-denied ACE that replaces any existing access-denied ACE for the trustee. The new ACE denies the specified rights in addition to any currently denied rights of the trustee. The function also modifies or deletes any existing access-allowed ACE for the trustee that allows the specified rights.
REVOKE_ACCESS	Removes any existing ACEs for the specified trustee. The function ignores the rights specified in the grfAccessPermissions member of the EXPLICIT_ACCESS structure.

The SetEntriesInAcl function places any new access-denied ACEs at the beginning of the list of ACEs for the new ACL. It places any new access-allowed ACEs just before any existing access-allowed ACEs.

For a SACL, the grfAccessMode member of the EXPLICIT_ACCESS structure can specify the following values.

Value	Meaning
REVOKE_ACCESS	Removes any existing ACEs for the specified trustee. The function ignores the rights specified in the grfAccessPermissions member of the EXPLICIT_ACCESS structure.
SET_AUDIT_SUCCESS	Creates a new system-audit ACE that replaces any existing system-audit ACE for the trustee. The new ACE generates audit messages when the specified trustee successfully uses the specified access rights. The new ACE combines the specified rights with any existing audited access rights for the trustee. You can combine this value with SET_AUDIT_FAILURE.
SET_AUDIT_FAILURE	Creates a new system-audit ACE that replaces any existing system-audit ACE for the trustee. The new ACE generates audit messages for failed attempts to use the specified access rights. The new ACE combines the specified rights with any existing audited access rights for the trustee. You can combine this value with SET_AUDIT_SUCCESS.

The SetEntriesInAcl function places any new system-audit ACEs at the beginning of the list of ACEs for the new ACL.

Requirements

  Windows NT/2000: Requires Windows NT 4.0 or later.
  Header: Declared in Aclapi.h.
  Library: Use Advapi32.lib.
  Unicode: Implemented as Unicode and ANSI versions on Windows NT/2000.

SetEntriesInAcl

Parameters

Return Values

Remarks

Requirements

See Also