问题
Hi all I've written a custom credentialprovider that works fine when using username/password as credential, the password is transferred via bluetooth. After all it was not that difficult as the documentation tells you what interfaces to implement.
Now I want to change the credentials to use certificates instead. I see that I should use the KERB_CERTIFICATE_LOGON structure for this. Diving deeper into the topic I found that I should implement a custom key storage provider as described in this article by microsoft. And that's the point where I am lost. Perhaps I am to silly to search for the right documentation but I just cannot find which interfaces I have to implement to have a KSP that I can refer to in the CspData-field of the KERB_CERTIFICATE_LOGON structure. I just find a bunch of methods and a quick search for NCRYPT_CERTIFICATE_PROPERTY (mentioned in the above linked article) revealed amazing two results in google.
I have found this SO-question that will help me connecting credentialprovider and KSP when I have one, but it does not explain how to write the KSP. :-(
Can anybody guide me where to find information or show a short sample of a KSP used in a similar scenario (just the method declarations, and how to use the resulting KSP in the call to KERB_CERTIFICATE_LOGON)?
回答1:
This Microsoft Cryptographic Provider Development Kit has a good sample of the KSP.
The only thing you need to do in addition to this sample is implement SmartCardKeyCertificate property. The code will be something like this:
SECURITY_STATUS
WINAPI
KSPGetKeyProperty(
__in NCRYPT_PROV_HANDLE hProvider,
__in NCRYPT_KEY_HANDLE hKey,
__in LPCWSTR pszProperty,
__out_bcount_part_opt(cbOutput, *pcbResult) PBYTE pbOutput,
__in DWORD cbOutput,
__out DWORD * pcbResult,
__in DWORD dwFlags)
{
...
if (wcscmp(pszProperty, NCRYPT_CERTIFICATE_PROPERTY) == 0)
{
dwProperty = SAMPLEKSP_CERTIFICATE_PROPERTY;
cbResult = GetCertificateSize(); //the size of the certificate that is associated with the key
}
*pcbResult = cbResult;
if(pbOutput == NULL)
{
Status = ERROR_SUCCESS;
goto cleanup;
}
if(cbOutput < *pcbResult)
{
Status = NTE_BUFFER_TOO_SMALL;
goto cleanup;
}
if (wcscmp(pszProperty, NCRYPT_CERTIFICATE_PROPERTY) == 0)
{
CopyMemory(pbOutput, crt, sizeof(crt));
}
switch(dwProperty)
{
case SAMPLEKSP_CERTIFICATE_PROPERTY:
CopyMemory(pbOutput, GetCertificate(), cbResult); //Copy to pbOutput the certificate in binary form
break;
...
}
...
}
After you implement KSP and register it, your CredentialProvider can interact with it:
HRESULT MyCredential::GetSerialization(
CREDENTIAL_PROVIDER_GET_SERIALIZATION_RESPONSE* pcpgsr,
CREDENTIAL_PROVIDER_CREDENTIAL_SERIALIZATION* pcpcs,
PWSTR* ppwszOptionalStatusText,
CREDENTIAL_PROVIDER_STATUS_ICON* pcpsiOptionalStatusIcon
)
{
...
ULONG ulAuthPackage;
HRESULT hr = RetrieveNegotiateAuthPackage(&ulAuthPackage);
ConstructAuthInfo(&pcpcs->rgbSerialization, &pcpcs->cbSerialization);
if (SUCCEEDED(hr))
{
pcpcs->ulAuthenticationPackage = ulAuthPackage;
pcpcs->clsidCredentialProvider = CLSID_MyCredentialProvider;
// At this point the credential has created the serialized credential used for logon
// By setting this to CPGSR_RETURN_CREDENTIAL_FINISHED we are letting logonUI know
// that we have all the information we need and it should attempt to submit the
// serialized credential.
*pcpgsr = CPGSR_RETURN_CREDENTIAL_FINISHED;
}
return hr;
}
HRESULT RetrieveNegotiateAuthPackage(ULONG * pulAuthPackage)
{
HRESULT hr = S_OK;
HANDLE hLsa = NULL;
NTSTATUS status = LsaConnectUntrusted(&hLsa);
if (SUCCEEDED(HRESULT_FROM_NT(status)))
{
ULONG ulAuthPackage;
LSA_STRING lsaszKerberosName;
LsaInitString(&lsaszKerberosName, MICROSOFT_KERBEROS_NAME_A);
status = LsaLookupAuthenticationPackage(hLsa, &lsaszKerberosName, &ulAuthPackage);
if (SUCCEEDED(HRESULT_FROM_NT(status)))
{
*pulAuthPackage = ulAuthPackage;
hr = S_OK;
}
else
{
hr = HRESULT_FROM_NT(status);
}
LsaDeregisterLogonProcess(hLsa);
}
else
{
hr = HRESULT_FROM_NT(status);
}
return hr;
}
void ConstructAuthInfo(LPBYTE* ppbAuthInfo, ULONG *pulAuthInfoLen)
{
WCHAR szCardName[] = L""; // no card name specified but you can put one if you want
WCHAR szContainerName[] = L"my_key_name";
WCHAR szReaderName[] = L"";
WCHAR szCspName[] = L"My Key Storage Provider";
WCHAR szPin[] = L"11111111";
ULONG ulPinByteLen = wcslen(szPin) * sizeof(WCHAR);
WCHAR szUserName[] = L"user";
ULONG ulUserByteLen = wcslen(szUserName) * sizeof(WCHAR);
WCHAR szDomainName[] = L"testdomain.com";
ULONG ulDomainByteLen = wcslen(szDomainName) * sizeof(WCHAR);
LPBYTE pbAuthInfo = NULL;
ULONG ulAuthInfoLen = 0;
KERB_CERTIFICATE_LOGON *pKerbCertLogon;
KERB_SMARTCARD_CSP_INFO *pKerbCspInfo;
LPBYTE pbDomainBuffer, pbUserBuffer, pbPinBuffer;
LPBYTE pbCspData;
LPBYTE pbCspDataContent;
ULONG ulCspDataLen = sizeof(KERB_SMARTCARD_CSP_INFO)-sizeof(TCHAR)+
(wcslen(szCardName) + 1) * sizeof(WCHAR)+
(wcslen(szCspName) + 1) * sizeof(WCHAR)+
(wcslen(szContainerName) + 1) * sizeof(WCHAR)+
(wcslen(szReaderName) + 1) * sizeof(WCHAR);
ulAuthInfoLen = sizeof(KERB_CERTIFICATE_LOGON)+
ulDomainByteLen + sizeof(WCHAR)+
ulUserByteLen + sizeof(WCHAR)+
ulPinByteLen + sizeof(WCHAR)+
ulCspDataLen;
pbAuthInfo = (LPBYTE)CoTaskMemAlloc(ulAuthInfoLen);
ZeroMemory(pbAuthInfo, ulAuthInfoLen);
pbDomainBuffer = pbAuthInfo + sizeof(KERB_CERTIFICATE_LOGON);
pbUserBuffer = pbDomainBuffer + ulDomainByteLen + sizeof(WCHAR);
pbPinBuffer = pbUserBuffer + ulUserByteLen + sizeof(WCHAR);
pbCspData = pbPinBuffer + ulPinByteLen + sizeof(WCHAR);
memcpy(pbDomainBuffer, szDomainName, ulDomainByteLen);
memcpy(pbUserBuffer, szUserName, ulUserByteLen);
memcpy(pbPinBuffer, szPin, ulPinByteLen);
pKerbCertLogon = (KERB_CERTIFICATE_LOGON*)pbAuthInfo;
pKerbCertLogon->MessageType = KerbCertificateLogon;
pKerbCertLogon->DomainName.Length = (USHORT)ulDomainByteLen;
pKerbCertLogon->DomainName.MaximumLength = (USHORT)(ulDomainByteLen + sizeof(WCHAR));
pKerbCertLogon->DomainName.Buffer = (PWSTR)(pbDomainBuffer-pbAuthInfo);
pKerbCertLogon->UserName.Length = (USHORT)ulUserByteLen;
pKerbCertLogon->UserName.MaximumLength = (USHORT)(ulUserByteLen + sizeof(WCHAR));
pKerbCertLogon->UserName.Buffer = (PWSTR)(pbUserBuffer-pbAuthInfo);
pKerbCertLogon->Pin.Length = (USHORT)ulPinByteLen;
pKerbCertLogon->Pin.MaximumLength = (USHORT)(ulPinByteLen + sizeof(WCHAR));
pKerbCertLogon->Pin.Buffer = (PWSTR)(pbPinBuffer-pbAuthInfo);
pKerbCertLogon->CspDataLength = ulCspDataLen;
pKerbCertLogon->CspData = (PUCHAR)(pbCspData-pbAuthInfo);
pKerbCspInfo = (KERB_SMARTCARD_CSP_INFO*)pbCspData;
pKerbCspInfo->dwCspInfoLen = ulCspDataLen;
pKerbCspInfo->MessageType = 1;
pKerbCspInfo->KeySpec = CERT_NCRYPT_KEY_SPEC;
pKerbCspInfo->nCardNameOffset = 0;
pKerbCspInfo->nReaderNameOffset = pKerbCspInfo->nCardNameOffset + wcslen(szCardName) + 1;
pKerbCspInfo->nContainerNameOffset = pKerbCspInfo->nReaderNameOffset + wcslen(szReaderName) + 1;
pKerbCspInfo->nCSPNameOffset = pKerbCspInfo->nContainerNameOffset + wcslen(szContainerName) + 1;
pbCspDataContent = pbCspData + sizeof(KERB_SMARTCARD_CSP_INFO)-sizeof(TCHAR);
memcpy(pbCspDataContent + (pKerbCspInfo->nCardNameOffset * sizeof(WCHAR)), szCardName, wcslen(szCardName) * sizeof(WCHAR));
memcpy(pbCspDataContent + (pKerbCspInfo->nReaderNameOffset * sizeof(WCHAR)), szReaderName, wcslen(szReaderName) * sizeof(WCHAR));
memcpy(pbCspDataContent + (pKerbCspInfo->nContainerNameOffset * sizeof(WCHAR)), szContainerName, wcslen(szContainerName) * sizeof(WCHAR));
memcpy(pbCspDataContent + (pKerbCspInfo->nCSPNameOffset * sizeof(WCHAR)), szCspName, wcslen(szCspName) * sizeof(WCHAR));
*ppbAuthInfo = pbAuthInfo;
*pulAuthInfoLen = ulAuthInfoLen;
}
There are two main things in this code:
- For interacting with the KSP, pKerbCspInfo->KeySpec must be CERT_NCRYPT_KEY_SPEC.
For proper structure serialization, according to this answer:
pKerbCertLogon->DomainName.Buffer = (PWSTR)(pbDomainBuffer-pbAuthInfo); pKerbCertLogon->UserName.Buffer = (PWSTR)(pbUserBuffer-pbAuthInfo); pKerbCertLogon->Pin.Buffer = (PWSTR)(pbPinBuffer-pbAuthInfo); pKerbCertLogon->CspData = (PUCHAR)(pbCspData-pbAuthInfo);
Also the domain controller should issue the certificate with "Kerberos Authentication" template.
来源：https://stackoverflow.com/questions/41869313/how-to-write-a-ksp-to-hook-up-into-kerb-certificate-logon