読み取りユーザーがパスワードを変更できない (LDAPプロバイダー)
ユーザーがパスワードを変更できるかどうかは、許可または拒否できるアクセス許可です。
パスワードの変更アクセス許可が付与または拒否されているかどうかを確認するには
ユーザーオブジェクトにバインドします。
ユーザーオブジェクトのntSecurityDescriptorプロパティからIADsSecurityDescriptorオブジェクトを取得します。
IADsSecurityDescriptor.DiscretionaryAclからセキュリティ記述子のIADsAccessControlListインターフェイスを取得します。
オブジェクトのアクセス制御エントリ（ACE）を列挙し、IADsAccessControlEntry.ObjectType プロパティに変更パスワードGUID（{AB721A53-1E2F-11D0-9819-00AA0040529B}）を持ち、IADsAccessControlEntry.Trusteeプロパティに「Everyone」または「NT AUTHORITYSELF」という既知のセキュリティプリンシパルを持つACEを検索します。
Note
"Everyone"と"NT AUTHORITY\SELF"の文字列は、ドメイン内の最初のドメインコントローラーの言語に基づいてローカライズされます。 したがって、文字列を直接使用しないでください。 アカウント名は、実行時に"Everyone"("S-1-1-0")と"NT AUTHORITY\SELF"("S-1-5-10")の既知のセキュリティプリンシパルのSIDを指定してLookupAccountSid関数を呼び出すことによって取得する必要があります。 次C++のGetSidAccountName、GetSidAccountName_Everyone、およびGetSidAccountName_Selfのコード例は、これを行う方法を示しています。"。
Everyone "および "NT AUTHORITY_SELF "ACEの両方が、IADsAccessControlEntry.AceTypeプロパティのADS_ACETYPE_ACCESS_DENIED_OBJECT>値を持つ場合、パーミッションは拒否されます。
コード例
次のコード例は、ユーザーがLDAPプロバイダーを使用してパスワードのアクセス許可を変更できないかどうかを確認する方法を示しています。
/***************************************************************************
GetSidAccountName()
Retrieves the account name for the specified SID.
pSid - Pointer to the SID that the account name should be retrieved for.
pbstrAccountName - Pointer to a BSTR that receives the account name. The
caller must free this with SysFreeString when it is no longer required.
***************************************************************************/
HRESULT GetSidAccountName(PSID pSid, BSTR *pbstrAccountName)
{
if(!pbstrAccountName)
{
return E_INVALIDARG;
}
HRESULT hr = E_FAIL;
BOOL fReturn;
WCHAR wszAccountName[MAX_PATH];
DWORD dwAccountName;
WCHAR wszDomainName[MAX_PATH];
DWORD dwDomainName;
SID_NAME_USE SidNameUse;
DWORD dwSidSize;
dwAccountName = MAX_PATH;
dwDomainName = MAX_PATH;
dwSidSize = SECURITY_MAX_SID_SIZE;
/*
Get the account name for the specified SID.
*/
fReturn = LookupAccountSidW(
NULL,
pSid,
wszAccountName,
&dwAccountName,
wszDomainName,
&dwDomainName,
&SidNameUse);
if(fReturn)
{
CComBSTR sbstrReturn;
if(lstrlenW(wszDomainName) > 0)
{
sbstrReturn = wszDomainName;
sbstrReturn += "\\";
sbstrReturn += wszAccountName;
}
else
{
sbstrReturn = wszAccountName;
}
*pbstrAccountName = sbstrReturn.Detach();
hr = S_OK;
}
return hr;
}
/***************************************************************************
GetSidAccountName_Everyone()
Retrieves the local account name for the "World", also known as
"Everyone", account.
pbstrAccountName - Pointer to a BSTR that receives the account name. The
caller must free this with SysFreeString when it is no longer required.
***************************************************************************/
HRESULT GetSidAccountName_Everyone(BSTR *pbstrAccountName)
{
if(!pbstrAccountName)
{
return E_INVALIDARG;
}
HRESULT hr = E_FAIL;
BOOL fReturn;
PSID psidAlloc;
// Create the SID for "Everyone".
SID_IDENTIFIER_AUTHORITY SidAuth = SECURITY_WORLD_SID_AUTHORITY;
fReturn = AllocateAndInitializeSid(
&SidAuth,
1,
SECURITY_WORLD_RID,
0, 0, 0, 0, 0, 0, 0,
&psidAlloc);
if(fReturn)
{
hr = GetSidAccountName(psidAlloc, pbstrAccountName);
LocalFree(psidAlloc);
}
return hr;
}
/***************************************************************************
GetSidAccountName_Self()
Retrieves the local account name for the "NT AUTHORITY\SELF" account.
pbstrAccountName - Pointer to a BSTR that receives the account name. The
caller must free this with SysFreeString when it is no longer required.
***************************************************************************/
HRESULT GetSidAccountName_Self(BSTR *pbstrAccountName)
{
HRESULT hr = E_FAIL;
BOOL fReturn;
PSID psidAlloc;
// Create the SID for "Everyone".
SID_IDENTIFIER_AUTHORITY SidAuth = SECURITY_NT_AUTHORITY;
fReturn = AllocateAndInitializeSid(
&SidAuth,
1,
SECURITY_PRINCIPAL_SELF_RID,
0, 0, 0, 0, 0, 0, 0,
&psidAlloc);
if(fReturn)
{
hr = GetSidAccountName(psidAlloc, pbstrAccountName);
LocalFree(psidAlloc);
}
return hr;
}
#define CHANGE_PASSWORD_GUID_W L"{AB721A53-1E2F-11D0-9819-00AA0040529B}"
/***************************************************************************
GetObjectACE()
Retrieves the IADsAccessControlEntry for the ACE that matches the
specified object type and trustee in the specified IADsAccessControlList.
Returns a value other than S_OK if the ACE is not found.
pACL - Pointer to an IADsAccessControlList object that will be searched.
pwszObject - Pointer to a null-terminated Unicode string that contains
the object type to find.
pwszTrustee - Pointer to a null-terminated Unicode string that contains
the trustee to find.
ppACE - Pointer to an IADsAccessControlEntry pointer that receives the
ACE if successful. This receives NULL if not successful.
***************************************************************************/
HRESULT GetObjectACE(IADsAccessControlList* pACL,
LPCWSTR pwszObject,
LPCWSTR pwszTrustee,
IADsAccessControlEntry** ppACE)
{
if(NULL == pACL || NULL == pwszObject)
{
return E_INVALIDARG;
}
*ppACE = NULL;
HRESULT hr;
IUnknown *pUnk;
hr = pACL->get__NewEnum(&pUnk);
if(FAILED(hr))
{
return hr;
}
IEnumVARIANT *pEnum;
hr = pUnk->QueryInterface(IID_IEnumVARIANT, (LPVOID*)&pEnum);
if(SUCCEEDED(hr))
{
ULONG ulFetched;
BOOL fEveryone = FALSE;
BOOL fSelf = FALSE;
CComVariant svarACE;
for(hr = pEnum->Next(1, &svarACE, &ulFetched);
S_OK == hr && 1 == ulFetched;
hr = pEnum->Next(1, &svarACE, &ulFetched))
{
if(VT_DISPATCH == svarACE.vt)
{
IADsAccessControlEntry *pACE;
hr = svarACE.pdispVal->QueryInterface(IID_IADsAccessControlEntry, (void**)&pACE);
if(SUCCEEDED(hr))
{
CComBSTR sbstrObjectType;
hr = pACE->get_ObjectType(&sbstrObjectType);
if(SUCCEEDED(hr))
{
if(0 == lstrcmpiW(pwszObject, sbstrObjectType))
{
CComBSTR sbstrTrustee;
hr = pACE->get_Trustee(&sbstrTrustee);
if(SUCCEEDED(hr) && (0 == lstrcmpiW(sbstrTrustee, pwszTrustee)))
{
*ppACE = pACE;
break;
}
}
}
pACE->Release();
}
}
}
pEnum->Release();
}
return hr;
}
/***************************************************************************
UserCannotChangePassword()
Retrieves the "User Cannot Change Password" privilege using the LDAP
provider. This is determined by the presence and value of the change
password GUID ACE for the Everyone and Self trustees. The default result
of this function is that the user can change their password unless the
two ACEs specifically deny the privilege.
pwszUserDN - A null-terminated Unicode string that contains the LDAP
ADsPath of the user object to verify.
pwszUsername - A null-terminated Unicode string that contains the user
name to use for authorization. If this is NULL, the credentials of the
current user are used.
pwszPassword - A null-terminated Unicode string that contains the
password to use for authorization. This is ignored if pwszUsername is
NULL.
pfCannotChangePassword - Receives the setting for the privilege.
Receives nonzero if the user cannot change their password or zero if
the can change their password.
***************************************************************************/
HRESULT UserCannotChangePassword(LPCWSTR pwszUserDN,
LPCWSTR pwszUsername,
LPCWSTR pwszPassword,
BOOL *pfCannotChangePassword)
{
HRESULT hr;
CComBSTR sbstrEveryone;
hr = GetSidAccountName_Everyone(&sbstrEveryone);
if(FAILED(hr))
{
return hr;
}
CComBSTR sbstrSelf;
hr = GetSidAccountName_Self(&sbstrSelf);
if(FAILED(hr))
{
return hr;
}
if(NULL == pwszUserDN)
{
return E_INVALIDARG;
}
IADs *pads;
*pfCannotChangePassword = FALSE;
hr = ADsOpenObject( pwszUserDN,
pwszUsername,
pwszPassword,
ADS_SECURE_AUTHENTICATION,
IID_IADs,
(LPVOID*)&pads);
if(SUCCEEDED(hr))
{
CComVariant svar;
hr = pads->Get(CComBSTR("ntSecurityDescriptor"), &svar);
if(SUCCEEDED(hr))
{
IADsSecurityDescriptor *psd;
hr = svar.pdispVal->QueryInterface(IID_IADsSecurityDescriptor, (LPVOID*)&psd);
if(SUCCEEDED(hr))
{
IDispatch *pDisp;
hr = psd->get_DiscretionaryAcl(&pDisp);
if(SUCCEEDED(hr))
{
IADsAccessControlList *pACL;
hr = pDisp->QueryInterface(IID_IADsAccessControlList, (void**)&pACL);
if(SUCCEEDED(hr))
{
BOOL fEveryone = FALSE;
BOOL fSelf = FALSE;
IADsAccessControlEntry *pACEEveryone = NULL;
IADsAccessControlEntry *pACESelf = NULL;
// Get the ACE for everyone.
hr = GetObjectACE(pACL, CHANGE_PASSWORD_GUID_W, sbstrEveryone, &pACEEveryone);
// Get the ACE for self.
hr = GetObjectACE(pACL, CHANGE_PASSWORD_GUID_W, sbstrSelf, &pACESelf);
if(pACEEveryone && pACESelf)
{
LONG lAceType;
hr = pACEEveryone->get_AceType(&lAceType);
if(SUCCEEDED(hr) && (ADS_ACETYPE_ACCESS_DENIED_OBJECT == lAceType))
{
fEveryone = TRUE;
}
hr = pACESelf->get_AceType(&lAceType);
if(SUCCEEDED(hr) && (ADS_ACETYPE_ACCESS_DENIED_OBJECT == lAceType))
{
fSelf = TRUE;
}
}
if(fEveryone && fSelf)
{
*pfCannotChangePassword = TRUE;
}
else
{
*pfCannotChangePassword = FALSE;
}
}
pDisp->Release();
}
psd->Release();
}
}
pads->Release();
}
return hr;
}
次のコード例は、ユーザーがLDAPプロバイダーを使用してパスワードのアクセス許可を変更できないかどうかを確認する方法を示しています。
Note
次のコード例は、"Everyone"と"NT AUTHORITY\SELF"の文字列がドメイン内の最初のドメインコントローラーの言語に基づいてローカライズされているため、プライマリ言語が英語であるドメインに対してのみ機能します。 Visual Basicでは、LookupAccountSid関数を呼び出さずに、既知のセキュリティプリンシパルのアカウント名を取得する方法はありません。 Visual Basicを使用している場合は、WinNTプロバイダーを使用して、 読み取りユーザーがパスワードを変更できない (WinNTプロバイダー) に示すように、ユーザーがパスワードのアクセス許可を変更できないかどうかを確認することをお勧めします。
Const CHANGE_PASSWORD_GUID = "{AB721A53-1E2F-11D0-9819-00AA0040529B}"
Const ADS_ACETYPE_ACCESS_DENIED_OBJECT = &H6
Function UserCannotChangePassword(strUserDN As String, strUsername As String, strPassword As String) As Boolean
UserCannotChangePassword = False
Dim oUser As IADs
Dim oSecDesc As IADsSecurityDescriptor
Dim oACL As IADsAccessControlList
Dim oACE As IADsAccessControlEntry
Dim fEveryone As Boolean
Dim fSelf As Boolean
fEveryone = False
fSelf = False
If "" <> strUsername Then
Dim dso As IADsOpenDSObject
' Bind to the group with the specified user name and password.
Set dso = GetObject("LDAP:")
Set oUser = dso.OpenDSObject(strUserDN, strUsername, strPassword, 1)
Else
' Bind to the group with the current credentials.
Set oUser = GetObject(strUserDN)
End If
Set oSecDesc = oUser.Get("ntSecurityDescriptor")
Set oACL = oSecDesc.DiscretionaryAcl
For Each oACE In oACL
If UCase(oACE.ObjectType) = UCase(CHANGE_PASSWORD_GUID) Then
If oACE.Trustee = "Everyone" And oACE.AceType = ADS_ACETYPE_ACCESS_DENIED_OBJECT Then
fEveryone = True
End If
If oACE.Trustee = "NT AUTHORITY\SELF" And oACE.AceType = ADS_ACETYPE_ACCESS_DENIED_OBJECT Then
fSelf = True
End If
End If
Next
If fSelf And fEveryone Then
UserCannotChangePassword = True
Else
UserCannotChangePassword = False
End If
End Function