sspi/NTLM/ntlm.c

 
#include <winpr/config.h>
 
#include <winpr/crt.h>
#include <winpr/assert.h>
#include <winpr/sspi.h>
#include <winpr/print.h>
#include <winpr/string.h>
#include <winpr/tchar.h>
#include <winpr/sysinfo.h>
#include <winpr/registry.h>
#include <winpr/endian.h>
#include <winpr/build-config.h>
 
#include "ntlm.h"
#include "ntlm_export.h"
#include "../sspi.h"
 
#include "ntlm_message.h"
 
#include "../../log.h"
#define TAG WINPR_TAG("sspi.NTLM")
 
#define WINPR_KEY "Software\\" WINPR_VENDOR_STRING "\\" WINPR_PRODUCT_STRING "\\WinPR\\NTLM"
 
static char* NTLM_PACKAGE_NAME = "NTLM";
 
#define check_context(ctx) check_context_((ctx), __FILE__, __func__, __LINE__)
static BOOL check_context_(NTLM_CONTEXT* context, const char* file, const char* fkt, size_t line)
{
  BOOL rc = TRUE;
  wLog* log = WLog_Get(TAG);
  const DWORD log_level = WLOG_ERROR;
 
  if (!context)
  {
    if (WLog_IsLevelActive(log, log_level))
      WLog_PrintMessage(log, WLOG_MESSAGE_TEXT, log_level, line, file, fkt,
                        "invalid context");
 
    return FALSE;
  }
 
  if (!context->RecvRc4Seal)
  {
    if (WLog_IsLevelActive(log, log_level))
      WLog_PrintMessage(log, WLOG_MESSAGE_TEXT, log_level, line, file, fkt,
                        "invalid context->RecvRc4Seal");
    rc = FALSE;
  }
  if (!context->SendRc4Seal)
  {
    if (WLog_IsLevelActive(log, log_level))
      WLog_PrintMessage(log, WLOG_MESSAGE_TEXT, log_level, line, file, fkt,
                        "invalid context->SendRc4Seal");
    rc = FALSE;
  }
 
  if (!context->SendSigningKey)
  {
    if (WLog_IsLevelActive(log, log_level))
      WLog_PrintMessage(log, WLOG_MESSAGE_TEXT, log_level, line, file, fkt,
                        "invalid context->SendSigningKey");
    rc = FALSE;
  }
  if (!context->RecvSigningKey)
  {
    if (WLog_IsLevelActive(log, log_level))
      WLog_PrintMessage(log, WLOG_MESSAGE_TEXT, log_level, line, file, fkt,
                        "invalid context->RecvSigningKey");
    rc = FALSE;
  }
  if (!context->SendSealingKey)
  {
    if (WLog_IsLevelActive(log, log_level))
      WLog_PrintMessage(log, WLOG_MESSAGE_TEXT, log_level, line, file, fkt,
                        "invalid context->SendSealingKey");
    rc = FALSE;
  }
  if (!context->RecvSealingKey)
  {
    if (WLog_IsLevelActive(log, log_level))
      WLog_PrintMessage(log, WLOG_MESSAGE_TEXT, log_level, line, file, fkt,
                        "invalid context->RecvSealingKey");
    rc = FALSE;
  }
  return rc;
}
 
static int ntlm_SetContextWorkstation(NTLM_CONTEXT* context, char* Workstation)
{
  char* ws = Workstation;
  DWORD nSize = 0;
  CHAR* computerName = NULL;
 
  WINPR_ASSERT(context);
 
  if (!Workstation)
  {
    if (GetComputerNameExA(ComputerNameNetBIOS, NULL, &nSize) ||
        GetLastError() != ERROR_MORE_DATA)
      return -1;
 
    computerName = calloc(nSize, sizeof(CHAR));
 
    if (!computerName)
      return -1;
 
    if (!GetComputerNameExA(ComputerNameNetBIOS, computerName, &nSize))
    {
      free(computerName);
      return -1;
    }
 
    if (nSize > MAX_COMPUTERNAME_LENGTH)
      computerName[MAX_COMPUTERNAME_LENGTH] = '\0';
 
    ws = computerName;
 
    if (!ws)
      return -1;
  }
 
  size_t len = 0;
  context->Workstation.Buffer = ConvertUtf8ToWCharAlloc(ws, &len);
 
  if (!Workstation)
    free(ws);
 
  if (!context->Workstation.Buffer || (len > UINT16_MAX / sizeof(WCHAR)))
    return -1;
 
  context->Workstation.Length = (USHORT)(len * sizeof(WCHAR));
  return 1;
}
 
static int ntlm_SetContextServicePrincipalNameW(NTLM_CONTEXT* context, LPWSTR ServicePrincipalName)
{
  WINPR_ASSERT(context);
 
  if (!ServicePrincipalName)
  {
    context->ServicePrincipalName.Buffer = NULL;
    context->ServicePrincipalName.Length = 0;
    return 1;
  }
 
  context->ServicePrincipalName.Length = (USHORT)(_wcslen(ServicePrincipalName) * 2);
  context->ServicePrincipalName.Buffer = (PWSTR)malloc(context->ServicePrincipalName.Length + 2);
 
  if (!context->ServicePrincipalName.Buffer)
    return -1;
 
  memcpy(context->ServicePrincipalName.Buffer, ServicePrincipalName,
         context->ServicePrincipalName.Length + 2);
  return 1;
}
 
static int ntlm_SetContextTargetName(NTLM_CONTEXT* context, char* TargetName)
{
  char* name = TargetName;
  DWORD nSize = 0;
  CHAR* computerName = NULL;
 
  WINPR_ASSERT(context);
 
  if (!name)
  {
    if (GetComputerNameExA(ComputerNameNetBIOS, NULL, &nSize) ||
        GetLastError() != ERROR_MORE_DATA)
      return -1;
 
    computerName = calloc(nSize, sizeof(CHAR));
 
    if (!computerName)
      return -1;
 
    if (!GetComputerNameExA(ComputerNameNetBIOS, computerName, &nSize))
    {
      free(computerName);
      return -1;
    }
 
    if (nSize > MAX_COMPUTERNAME_LENGTH)
      computerName[MAX_COMPUTERNAME_LENGTH] = '\0';
 
    name = computerName;
 
    if (!name)
      return -1;
 
    CharUpperA(name);
  }
 
  size_t len = 0;
  context->TargetName.pvBuffer = ConvertUtf8ToWCharAlloc(name, &len);
 
  if (!context->TargetName.pvBuffer || (len > UINT16_MAX / sizeof(WCHAR)))
  {
    free(context->TargetName.pvBuffer);
    context->TargetName.pvBuffer = NULL;
 
    if (!TargetName)
      free(name);
 
    return -1;
  }
 
  context->TargetName.cbBuffer = (USHORT)(len * sizeof(WCHAR));
 
  if (!TargetName)
    free(name);
 
  return 1;
}
 
static NTLM_CONTEXT* ntlm_ContextNew(void)
{
  HKEY hKey = 0;
  LONG status = 0;
  DWORD dwType = 0;
  DWORD dwSize = 0;
  DWORD dwValue = 0;
  NTLM_CONTEXT* context = (NTLM_CONTEXT*)calloc(1, sizeof(NTLM_CONTEXT));
 
  if (!context)
    return NULL;
 
  context->NTLMv2 = TRUE;
  context->UseMIC = FALSE;
  context->SendVersionInfo = TRUE;
  context->SendSingleHostData = FALSE;
  context->SendWorkstationName = TRUE;
  context->NegotiateKeyExchange = TRUE;
  context->UseSamFileDatabase = TRUE;
  status = RegOpenKeyExA(HKEY_LOCAL_MACHINE, WINPR_KEY, 0, KEY_READ | KEY_WOW64_64KEY, &hKey);
 
  if (status == ERROR_SUCCESS)
  {
    if (RegQueryValueEx(hKey, _T("NTLMv2"), NULL, &dwType, (BYTE*)&dwValue, &dwSize) ==
        ERROR_SUCCESS)
      context->NTLMv2 = dwValue ? 1 : 0;
 
    if (RegQueryValueEx(hKey, _T("UseMIC"), NULL, &dwType, (BYTE*)&dwValue, &dwSize) ==
        ERROR_SUCCESS)
      context->UseMIC = dwValue ? 1 : 0;
 
    if (RegQueryValueEx(hKey, _T("SendVersionInfo"), NULL, &dwType, (BYTE*)&dwValue, &dwSize) ==
        ERROR_SUCCESS)
      context->SendVersionInfo = dwValue ? 1 : 0;
 
    if (RegQueryValueEx(hKey, _T("SendSingleHostData"), NULL, &dwType, (BYTE*)&dwValue,
                        &dwSize) == ERROR_SUCCESS)
      context->SendSingleHostData = dwValue ? 1 : 0;
 
    if (RegQueryValueEx(hKey, _T("SendWorkstationName"), NULL, &dwType, (BYTE*)&dwValue,
                        &dwSize) == ERROR_SUCCESS)
      context->SendWorkstationName = dwValue ? 1 : 0;
 
    if (RegQueryValueEx(hKey, _T("WorkstationName"), NULL, &dwType, NULL, &dwSize) ==
        ERROR_SUCCESS)
    {
      char* workstation = (char*)malloc(dwSize + 1);
 
      if (!workstation)
      {
        free(context);
        return NULL;
      }
 
      status = RegQueryValueExA(hKey, "WorkstationName", NULL, &dwType, (BYTE*)workstation,
                                &dwSize);
      if (status != ERROR_SUCCESS)
        WLog_WARN(TAG, "Key ''WorkstationName' not found");
      workstation[dwSize] = '\0';
 
      if (ntlm_SetContextWorkstation(context, workstation) < 0)
      {
        free(workstation);
        free(context);
        return NULL;
      }
 
      free(workstation);
    }
 
    RegCloseKey(hKey);
  }
 
  /*
   * Extended Protection is enabled by default in Windows 7,
   * but enabling it in WinPR breaks TS Gateway at this point
   */
  context->SuppressExtendedProtection = FALSE;
  status = RegOpenKeyEx(HKEY_LOCAL_MACHINE, _T("System\\CurrentControlSet\\Control\\LSA"), 0,
                        KEY_READ | KEY_WOW64_64KEY, &hKey);
 
  if (status == ERROR_SUCCESS)
  {
    if (RegQueryValueEx(hKey, _T("SuppressExtendedProtection"), NULL, &dwType, (BYTE*)&dwValue,
                        &dwSize) == ERROR_SUCCESS)
      context->SuppressExtendedProtection = dwValue ? 1 : 0;
 
    RegCloseKey(hKey);
  }
 
  context->NegotiateFlags = 0;
  context->LmCompatibilityLevel = 3;
  ntlm_change_state(context, NTLM_STATE_INITIAL);
  FillMemory(context->MachineID, sizeof(context->MachineID), 0xAA);
 
  if (context->NTLMv2)
    context->UseMIC = TRUE;
 
  return context;
}
 
static void ntlm_ContextFree(NTLM_CONTEXT* context)
{
  if (!context)
    return;
 
  winpr_RC4_Free(context->SendRc4Seal);
  winpr_RC4_Free(context->RecvRc4Seal);
  sspi_SecBufferFree(&context->NegotiateMessage);
  sspi_SecBufferFree(&context->ChallengeMessage);
  sspi_SecBufferFree(&context->AuthenticateMessage);
  sspi_SecBufferFree(&context->ChallengeTargetInfo);
  sspi_SecBufferFree(&context->TargetName);
  sspi_SecBufferFree(&context->NtChallengeResponse);
  sspi_SecBufferFree(&context->LmChallengeResponse);
  free(context->ServicePrincipalName.Buffer);
  free(context->Workstation.Buffer);
  free(context);
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_AcquireCredentialsHandleW(
    SEC_WCHAR* pszPrincipal, SEC_WCHAR* pszPackage, ULONG fCredentialUse, void* pvLogonID,
    void* pAuthData, SEC_GET_KEY_FN pGetKeyFn, void* pvGetKeyArgument, PCredHandle phCredential,
    PTimeStamp ptsExpiry)
{
  SEC_WINPR_NTLM_SETTINGS* settings = NULL;
 
  if ((fCredentialUse != SECPKG_CRED_OUTBOUND) && (fCredentialUse != SECPKG_CRED_INBOUND) &&
      (fCredentialUse != SECPKG_CRED_BOTH))
  {
    return SEC_E_INVALID_PARAMETER;
  }
 
  SSPI_CREDENTIALS* credentials = sspi_CredentialsNew();
 
  if (!credentials)
    return SEC_E_INTERNAL_ERROR;
 
  credentials->fCredentialUse = fCredentialUse;
  credentials->pGetKeyFn = pGetKeyFn;
  credentials->pvGetKeyArgument = pvGetKeyArgument;
 
  if (pAuthData)
  {
    UINT32 identityFlags = sspi_GetAuthIdentityFlags(pAuthData);
 
    sspi_CopyAuthIdentity(&(credentials->identity),
                          (const SEC_WINNT_AUTH_IDENTITY_INFO*)pAuthData);
 
    if (identityFlags & SEC_WINNT_AUTH_IDENTITY_EXTENDED)
      settings = (((SEC_WINNT_AUTH_IDENTITY_WINPR*)pAuthData)->ntlmSettings);
  }
 
  if (settings)
  {
    if (settings->samFile)
    {
      credentials->ntlmSettings.samFile = _strdup(settings->samFile);
      if (!credentials->ntlmSettings.samFile)
      {
        sspi_CredentialsFree(credentials);
        return SEC_E_INSUFFICIENT_MEMORY;
      }
    }
    credentials->ntlmSettings.hashCallback = settings->hashCallback;
    credentials->ntlmSettings.hashCallbackArg = settings->hashCallbackArg;
  }
 
  sspi_SecureHandleSetLowerPointer(phCredential, (void*)credentials);
  sspi_SecureHandleSetUpperPointer(phCredential, (void*)NTLM_PACKAGE_NAME);
  return SEC_E_OK;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_AcquireCredentialsHandleA(
    SEC_CHAR* pszPrincipal, SEC_CHAR* pszPackage, ULONG fCredentialUse, void* pvLogonID,
    void* pAuthData, SEC_GET_KEY_FN pGetKeyFn, void* pvGetKeyArgument, PCredHandle phCredential,
    PTimeStamp ptsExpiry)
{
  SECURITY_STATUS status = SEC_E_INSUFFICIENT_MEMORY;
  SEC_WCHAR* principal = NULL;
  SEC_WCHAR* package = NULL;
 
  if (pszPrincipal)
  {
    principal = ConvertUtf8ToWCharAlloc(pszPrincipal, NULL);
    if (!principal)
      goto fail;
  }
  if (pszPackage)
  {
    package = ConvertUtf8ToWCharAlloc(pszPackage, NULL);
    if (!package)
      goto fail;
  }
 
  status =
      ntlm_AcquireCredentialsHandleW(principal, package, fCredentialUse, pvLogonID, pAuthData,
                                     pGetKeyFn, pvGetKeyArgument, phCredential, ptsExpiry);
 
fail:
  free(principal);
  free(package);
 
  return status;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_FreeCredentialsHandle(PCredHandle phCredential)
{
  if (!phCredential)
    return SEC_E_INVALID_HANDLE;
 
  SSPI_CREDENTIALS* credentials =
      (SSPI_CREDENTIALS*)sspi_SecureHandleGetLowerPointer(phCredential);
 
  if (!credentials)
    return SEC_E_INVALID_HANDLE;
 
  sspi_CredentialsFree(credentials);
  return SEC_E_OK;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_QueryCredentialsAttributesW(PCredHandle phCredential,
                                                                  ULONG ulAttribute, void* pBuffer)
{
  if (ulAttribute == SECPKG_CRED_ATTR_NAMES)
  {
    return SEC_E_OK;
  }
 
  WLog_ERR(TAG, "TODO: Implement");
  return SEC_E_UNSUPPORTED_FUNCTION;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_QueryCredentialsAttributesA(PCredHandle phCredential,
                                                                  ULONG ulAttribute, void* pBuffer)
{
  return ntlm_QueryCredentialsAttributesW(phCredential, ulAttribute, pBuffer);
}
 
static SECURITY_STATUS SEC_ENTRY
ntlm_AcceptSecurityContext(PCredHandle phCredential, PCtxtHandle phContext, PSecBufferDesc pInput,
                           ULONG fContextReq, ULONG TargetDataRep, PCtxtHandle phNewContext,
                           PSecBufferDesc pOutput, PULONG pfContextAttr, PTimeStamp ptsTimeStamp)
{
  SECURITY_STATUS status = 0;
  SSPI_CREDENTIALS* credentials = NULL;
  PSecBuffer input_buffer = NULL;
  PSecBuffer output_buffer = NULL;
 
  /* behave like windows SSPIs that don't want empty context */
  if (phContext && !phContext->dwLower && !phContext->dwUpper)
    return SEC_E_INVALID_HANDLE;
 
  NTLM_CONTEXT* context = (NTLM_CONTEXT*)sspi_SecureHandleGetLowerPointer(phContext);
 
  if (!context)
  {
    context = ntlm_ContextNew();
 
    if (!context)
      return SEC_E_INSUFFICIENT_MEMORY;
 
    context->server = TRUE;
 
    if (fContextReq & ASC_REQ_CONFIDENTIALITY)
      context->confidentiality = TRUE;
 
    credentials = (SSPI_CREDENTIALS*)sspi_SecureHandleGetLowerPointer(phCredential);
    context->credentials = credentials;
    context->SamFile = credentials->ntlmSettings.samFile;
    context->HashCallback = credentials->ntlmSettings.hashCallback;
    context->HashCallbackArg = credentials->ntlmSettings.hashCallbackArg;
 
    ntlm_SetContextTargetName(context, NULL);
    sspi_SecureHandleSetLowerPointer(phNewContext, context);
    sspi_SecureHandleSetUpperPointer(phNewContext, (void*)NTLM_PACKAGE_NAME);
  }
 
  switch (ntlm_get_state(context))
  {
    case NTLM_STATE_INITIAL:
    {
      ntlm_change_state(context, NTLM_STATE_NEGOTIATE);
 
      if (!pInput)
        return SEC_E_INVALID_TOKEN;
 
      if (pInput->cBuffers < 1)
        return SEC_E_INVALID_TOKEN;
 
      input_buffer = sspi_FindSecBuffer(pInput, SECBUFFER_TOKEN);
 
      if (!input_buffer)
        return SEC_E_INVALID_TOKEN;
 
      if (input_buffer->cbBuffer < 1)
        return SEC_E_INVALID_TOKEN;
 
      status = ntlm_read_NegotiateMessage(context, input_buffer);
      if (status != SEC_I_CONTINUE_NEEDED)
        return status;
 
      if (ntlm_get_state(context) == NTLM_STATE_CHALLENGE)
      {
        if (!pOutput)
          return SEC_E_INVALID_TOKEN;
 
        if (pOutput->cBuffers < 1)
          return SEC_E_INVALID_TOKEN;
 
        output_buffer = sspi_FindSecBuffer(pOutput, SECBUFFER_TOKEN);
 
        if (!output_buffer->BufferType)
          return SEC_E_INVALID_TOKEN;
 
        if (output_buffer->cbBuffer < 1)
          return SEC_E_INSUFFICIENT_MEMORY;
 
        return ntlm_write_ChallengeMessage(context, output_buffer);
      }
 
      return SEC_E_OUT_OF_SEQUENCE;
    }
 
    case NTLM_STATE_AUTHENTICATE:
    {
      if (!pInput)
        return SEC_E_INVALID_TOKEN;
 
      if (pInput->cBuffers < 1)
        return SEC_E_INVALID_TOKEN;
 
      input_buffer = sspi_FindSecBuffer(pInput, SECBUFFER_TOKEN);
 
      if (!input_buffer)
        return SEC_E_INVALID_TOKEN;
 
      if (input_buffer->cbBuffer < 1)
        return SEC_E_INVALID_TOKEN;
 
      status = ntlm_read_AuthenticateMessage(context, input_buffer);
 
      if (pOutput)
      {
        for (ULONG i = 0; i < pOutput->cBuffers; i++)
        {
          pOutput->pBuffers[i].cbBuffer = 0;
          pOutput->pBuffers[i].BufferType = SECBUFFER_TOKEN;
        }
      }
 
      return status;
    }
 
    default:
      return SEC_E_OUT_OF_SEQUENCE;
  }
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_ImpersonateSecurityContext(PCtxtHandle phContext)
{
  return SEC_E_OK;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_InitializeSecurityContextW(
    PCredHandle phCredential, PCtxtHandle phContext, SEC_WCHAR* pszTargetName, ULONG fContextReq,
    ULONG Reserved1, ULONG TargetDataRep, PSecBufferDesc pInput, ULONG Reserved2,
    PCtxtHandle phNewContext, PSecBufferDesc pOutput, PULONG pfContextAttr, PTimeStamp ptsExpiry)
{
  SECURITY_STATUS status = 0;
  SSPI_CREDENTIALS* credentials = NULL;
  PSecBuffer input_buffer = NULL;
  PSecBuffer output_buffer = NULL;
 
  /* behave like windows SSPIs that don't want empty context */
  if (phContext && !phContext->dwLower && !phContext->dwUpper)
    return SEC_E_INVALID_HANDLE;
 
  NTLM_CONTEXT* context = (NTLM_CONTEXT*)sspi_SecureHandleGetLowerPointer(phContext);
 
  if (pInput)
  {
    input_buffer = sspi_FindSecBuffer(pInput, SECBUFFER_TOKEN);
  }
 
  if (!context)
  {
    context = ntlm_ContextNew();
 
    if (!context)
      return SEC_E_INSUFFICIENT_MEMORY;
 
    if (fContextReq & ISC_REQ_CONFIDENTIALITY)
      context->confidentiality = TRUE;
 
    credentials = (SSPI_CREDENTIALS*)sspi_SecureHandleGetLowerPointer(phCredential);
    context->credentials = credentials;
 
    if (context->Workstation.Length < 1)
    {
      if (ntlm_SetContextWorkstation(context, NULL) < 0)
      {
        ntlm_ContextFree(context);
        return SEC_E_INTERNAL_ERROR;
      }
    }
 
    if (ntlm_SetContextServicePrincipalNameW(context, pszTargetName) < 0)
    {
      ntlm_ContextFree(context);
      return SEC_E_INTERNAL_ERROR;
    }
 
    sspi_SecureHandleSetLowerPointer(phNewContext, context);
    sspi_SecureHandleSetUpperPointer(phNewContext, NTLM_SSP_NAME);
  }
 
  if ((!input_buffer) || (ntlm_get_state(context) == NTLM_STATE_AUTHENTICATE))
  {
    if (!pOutput)
      return SEC_E_INVALID_TOKEN;
 
    if (pOutput->cBuffers < 1)
      return SEC_E_INVALID_TOKEN;
 
    output_buffer = sspi_FindSecBuffer(pOutput, SECBUFFER_TOKEN);
 
    if (!output_buffer)
      return SEC_E_INVALID_TOKEN;
 
    if (output_buffer->cbBuffer < 1)
      return SEC_E_INVALID_TOKEN;
 
    if (ntlm_get_state(context) == NTLM_STATE_INITIAL)
      ntlm_change_state(context, NTLM_STATE_NEGOTIATE);
 
    if (ntlm_get_state(context) == NTLM_STATE_NEGOTIATE)
      return ntlm_write_NegotiateMessage(context, output_buffer);
 
    return SEC_E_OUT_OF_SEQUENCE;
  }
  else
  {
    if (!input_buffer)
      return SEC_E_INVALID_TOKEN;
 
    if (input_buffer->cbBuffer < 1)
      return SEC_E_INVALID_TOKEN;
 
    PSecBuffer channel_bindings = sspi_FindSecBuffer(pInput, SECBUFFER_CHANNEL_BINDINGS);
 
    if (channel_bindings)
    {
      context->Bindings.BindingsLength = channel_bindings->cbBuffer;
      context->Bindings.Bindings = (SEC_CHANNEL_BINDINGS*)channel_bindings->pvBuffer;
    }
 
    if (ntlm_get_state(context) == NTLM_STATE_CHALLENGE)
    {
      status = ntlm_read_ChallengeMessage(context, input_buffer);
 
      if (status != SEC_I_CONTINUE_NEEDED)
        return status;
 
      if (!pOutput)
        return SEC_E_INVALID_TOKEN;
 
      if (pOutput->cBuffers < 1)
        return SEC_E_INVALID_TOKEN;
 
      output_buffer = sspi_FindSecBuffer(pOutput, SECBUFFER_TOKEN);
 
      if (!output_buffer)
        return SEC_E_INVALID_TOKEN;
 
      if (output_buffer->cbBuffer < 1)
        return SEC_E_INSUFFICIENT_MEMORY;
 
      if (ntlm_get_state(context) == NTLM_STATE_AUTHENTICATE)
        return ntlm_write_AuthenticateMessage(context, output_buffer);
    }
 
    return SEC_E_OUT_OF_SEQUENCE;
  }
 
  return SEC_E_OUT_OF_SEQUENCE;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_InitializeSecurityContextA(
    PCredHandle phCredential, PCtxtHandle phContext, SEC_CHAR* pszTargetName, ULONG fContextReq,
    ULONG Reserved1, ULONG TargetDataRep, PSecBufferDesc pInput, ULONG Reserved2,
    PCtxtHandle phNewContext, PSecBufferDesc pOutput, PULONG pfContextAttr, PTimeStamp ptsExpiry)
{
  SECURITY_STATUS status = 0;
  SEC_WCHAR* pszTargetNameW = NULL;
 
  if (pszTargetName)
  {
    pszTargetNameW = ConvertUtf8ToWCharAlloc(pszTargetName, NULL);
    if (!pszTargetNameW)
      return SEC_E_INTERNAL_ERROR;
  }
 
  status = ntlm_InitializeSecurityContextW(phCredential, phContext, pszTargetNameW, fContextReq,
                                           Reserved1, TargetDataRep, pInput, Reserved2,
                                           phNewContext, pOutput, pfContextAttr, ptsExpiry);
  free(pszTargetNameW);
  return status;
}
 
/* http://msdn.microsoft.com/en-us/library/windows/desktop/aa375354 */
 
static SECURITY_STATUS SEC_ENTRY ntlm_DeleteSecurityContext(PCtxtHandle phContext)
{
  NTLM_CONTEXT* context = (NTLM_CONTEXT*)sspi_SecureHandleGetLowerPointer(phContext);
  ntlm_ContextFree(context);
  return SEC_E_OK;
}
 
SECURITY_STATUS ntlm_computeProofValue(NTLM_CONTEXT* ntlm, SecBuffer* ntproof)
{
  BYTE* blob = NULL;
  SecBuffer* target = NULL;
 
  WINPR_ASSERT(ntlm);
  WINPR_ASSERT(ntproof);
 
  target = &ntlm->ChallengeTargetInfo;
 
  if (!sspi_SecBufferAlloc(ntproof, 36 + target->cbBuffer))
    return SEC_E_INSUFFICIENT_MEMORY;
 
  blob = (BYTE*)ntproof->pvBuffer;
  CopyMemory(blob, ntlm->ServerChallenge, 8); /* Server challenge. */
  blob[8] = 1;                                /* Response version. */
  blob[9] = 1; /* Highest response version understood by the client. */
  /* Reserved 6B. */
  CopyMemory(&blob[16], ntlm->Timestamp, 8);       /* Time. */
  CopyMemory(&blob[24], ntlm->ClientChallenge, 8); /* Client challenge. */
  /* Reserved 4B. */
  /* Server name. */
  CopyMemory(&blob[36], target->pvBuffer, target->cbBuffer);
  return SEC_E_OK;
}
 
SECURITY_STATUS ntlm_computeMicValue(NTLM_CONTEXT* ntlm, SecBuffer* micvalue)
{
  BYTE* blob = NULL;
  ULONG msgSize = 0;
 
  WINPR_ASSERT(ntlm);
  WINPR_ASSERT(micvalue);
 
  msgSize = ntlm->NegotiateMessage.cbBuffer + ntlm->ChallengeMessage.cbBuffer +
            ntlm->AuthenticateMessage.cbBuffer;
 
  if (!sspi_SecBufferAlloc(micvalue, msgSize))
    return SEC_E_INSUFFICIENT_MEMORY;
 
  blob = (BYTE*)micvalue->pvBuffer;
  CopyMemory(blob, ntlm->NegotiateMessage.pvBuffer, ntlm->NegotiateMessage.cbBuffer);
  blob += ntlm->NegotiateMessage.cbBuffer;
  CopyMemory(blob, ntlm->ChallengeMessage.pvBuffer, ntlm->ChallengeMessage.cbBuffer);
  blob += ntlm->ChallengeMessage.cbBuffer;
  CopyMemory(blob, ntlm->AuthenticateMessage.pvBuffer, ntlm->AuthenticateMessage.cbBuffer);
  blob += ntlm->MessageIntegrityCheckOffset;
  ZeroMemory(blob, 16);
  return SEC_E_OK;
}
 
/* http://msdn.microsoft.com/en-us/library/windows/desktop/aa379337/ */
 
static SECURITY_STATUS SEC_ENTRY ntlm_QueryContextAttributesW(PCtxtHandle phContext,
                                                              ULONG ulAttribute, void* pBuffer)
{
  if (!phContext)
    return SEC_E_INVALID_HANDLE;
 
  if (!pBuffer)
    return SEC_E_INSUFFICIENT_MEMORY;
 
  NTLM_CONTEXT* context = (NTLM_CONTEXT*)sspi_SecureHandleGetLowerPointer(phContext);
  if (!check_context(context))
    return SEC_E_INVALID_HANDLE;
 
  if (ulAttribute == SECPKG_ATTR_SIZES)
  {
    SecPkgContext_Sizes* ContextSizes = (SecPkgContext_Sizes*)pBuffer;
    ContextSizes->cbMaxToken = 2010;
    ContextSizes->cbMaxSignature = 16;    /* the size of expected signature is 16 bytes */
    ContextSizes->cbBlockSize = 0;        /* no padding */
    ContextSizes->cbSecurityTrailer = 16; /* no security trailer appended in NTLM
                                contrary to Kerberos */
    return SEC_E_OK;
  }
  else if (ulAttribute == SECPKG_ATTR_AUTH_IDENTITY)
  {
    SSPI_CREDENTIALS* credentials = NULL;
    const SecPkgContext_AuthIdentity empty = { 0 };
    SecPkgContext_AuthIdentity* AuthIdentity = (SecPkgContext_AuthIdentity*)pBuffer;
 
    WINPR_ASSERT(AuthIdentity);
    *AuthIdentity = empty;
 
    context->UseSamFileDatabase = FALSE;
    credentials = context->credentials;
 
    if (credentials->identity.UserLength > 0)
    {
      if (ConvertWCharNToUtf8(credentials->identity.User, credentials->identity.UserLength,
                              AuthIdentity->User, ARRAYSIZE(AuthIdentity->User)) <= 0)
        return SEC_E_INTERNAL_ERROR;
    }
 
    if (credentials->identity.DomainLength > 0)
    {
      if (ConvertWCharNToUtf8(credentials->identity.Domain,
                              credentials->identity.DomainLength, AuthIdentity->Domain,
                              ARRAYSIZE(AuthIdentity->Domain)) <= 0)
        return SEC_E_INTERNAL_ERROR;
    }
 
    return SEC_E_OK;
  }
  else if (ulAttribute == SECPKG_ATTR_AUTH_NTLM_NTPROOF_VALUE)
  {
    return ntlm_computeProofValue(context, (SecBuffer*)pBuffer);
  }
  else if (ulAttribute == SECPKG_ATTR_AUTH_NTLM_RANDKEY)
  {
    SecBuffer* randkey = NULL;
    randkey = (SecBuffer*)pBuffer;
 
    if (!sspi_SecBufferAlloc(randkey, 16))
      return (SEC_E_INSUFFICIENT_MEMORY);
 
    CopyMemory(randkey->pvBuffer, context->EncryptedRandomSessionKey, 16);
    return (SEC_E_OK);
  }
  else if (ulAttribute == SECPKG_ATTR_AUTH_NTLM_MIC)
  {
    SecBuffer* mic = (SecBuffer*)pBuffer;
    NTLM_AUTHENTICATE_MESSAGE* message = &context->AUTHENTICATE_MESSAGE;
 
    if (!sspi_SecBufferAlloc(mic, 16))
      return (SEC_E_INSUFFICIENT_MEMORY);
 
    CopyMemory(mic->pvBuffer, message->MessageIntegrityCheck, 16);
    return (SEC_E_OK);
  }
  else if (ulAttribute == SECPKG_ATTR_AUTH_NTLM_MIC_VALUE)
  {
    return ntlm_computeMicValue(context, (SecBuffer*)pBuffer);
  }
 
  WLog_ERR(TAG, "TODO: Implement ulAttribute=0x%08" PRIx32, ulAttribute);
  return SEC_E_UNSUPPORTED_FUNCTION;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_QueryContextAttributesA(PCtxtHandle phContext,
                                                              ULONG ulAttribute, void* pBuffer)
{
  return ntlm_QueryContextAttributesW(phContext, ulAttribute, pBuffer);
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_SetContextAttributesW(PCtxtHandle phContext,
                                                            ULONG ulAttribute, void* pBuffer,
                                                            ULONG cbBuffer)
{
  if (!phContext)
    return SEC_E_INVALID_HANDLE;
 
  if (!pBuffer)
    return SEC_E_INVALID_PARAMETER;
 
  NTLM_CONTEXT* context = (NTLM_CONTEXT*)sspi_SecureHandleGetLowerPointer(phContext);
  if (!context)
    return SEC_E_INVALID_HANDLE;
 
  if (ulAttribute == SECPKG_ATTR_AUTH_NTLM_HASH)
  {
    SecPkgContext_AuthNtlmHash* AuthNtlmHash = (SecPkgContext_AuthNtlmHash*)pBuffer;
 
    if (cbBuffer < sizeof(SecPkgContext_AuthNtlmHash))
      return SEC_E_INVALID_PARAMETER;
 
    if (AuthNtlmHash->Version == 1)
      CopyMemory(context->NtlmHash, AuthNtlmHash->NtlmHash, 16);
    else if (AuthNtlmHash->Version == 2)
      CopyMemory(context->NtlmV2Hash, AuthNtlmHash->NtlmHash, 16);
 
    return SEC_E_OK;
  }
  else if (ulAttribute == SECPKG_ATTR_AUTH_NTLM_MESSAGE)
  {
    SecPkgContext_AuthNtlmMessage* AuthNtlmMessage = (SecPkgContext_AuthNtlmMessage*)pBuffer;
 
    if (cbBuffer < sizeof(SecPkgContext_AuthNtlmMessage))
      return SEC_E_INVALID_PARAMETER;
 
    if (AuthNtlmMessage->type == 1)
    {
      sspi_SecBufferFree(&context->NegotiateMessage);
 
      if (!sspi_SecBufferAlloc(&context->NegotiateMessage, AuthNtlmMessage->length))
        return SEC_E_INSUFFICIENT_MEMORY;
 
      CopyMemory(context->NegotiateMessage.pvBuffer, AuthNtlmMessage->buffer,
                 AuthNtlmMessage->length);
    }
    else if (AuthNtlmMessage->type == 2)
    {
      sspi_SecBufferFree(&context->ChallengeMessage);
 
      if (!sspi_SecBufferAlloc(&context->ChallengeMessage, AuthNtlmMessage->length))
        return SEC_E_INSUFFICIENT_MEMORY;
 
      CopyMemory(context->ChallengeMessage.pvBuffer, AuthNtlmMessage->buffer,
                 AuthNtlmMessage->length);
    }
    else if (AuthNtlmMessage->type == 3)
    {
      sspi_SecBufferFree(&context->AuthenticateMessage);
 
      if (!sspi_SecBufferAlloc(&context->AuthenticateMessage, AuthNtlmMessage->length))
        return SEC_E_INSUFFICIENT_MEMORY;
 
      CopyMemory(context->AuthenticateMessage.pvBuffer, AuthNtlmMessage->buffer,
                 AuthNtlmMessage->length);
    }
 
    return SEC_E_OK;
  }
  else if (ulAttribute == SECPKG_ATTR_AUTH_NTLM_TIMESTAMP)
  {
    SecPkgContext_AuthNtlmTimestamp* AuthNtlmTimestamp =
        (SecPkgContext_AuthNtlmTimestamp*)pBuffer;
 
    if (cbBuffer < sizeof(SecPkgContext_AuthNtlmTimestamp))
      return SEC_E_INVALID_PARAMETER;
 
    if (AuthNtlmTimestamp->ChallengeOrResponse)
      CopyMemory(context->ChallengeTimestamp, AuthNtlmTimestamp->Timestamp, 8);
    else
      CopyMemory(context->Timestamp, AuthNtlmTimestamp->Timestamp, 8);
 
    return SEC_E_OK;
  }
  else if (ulAttribute == SECPKG_ATTR_AUTH_NTLM_CLIENT_CHALLENGE)
  {
    SecPkgContext_AuthNtlmClientChallenge* AuthNtlmClientChallenge =
        (SecPkgContext_AuthNtlmClientChallenge*)pBuffer;
 
    if (cbBuffer < sizeof(SecPkgContext_AuthNtlmClientChallenge))
      return SEC_E_INVALID_PARAMETER;
 
    CopyMemory(context->ClientChallenge, AuthNtlmClientChallenge->ClientChallenge, 8);
    return SEC_E_OK;
  }
  else if (ulAttribute == SECPKG_ATTR_AUTH_NTLM_SERVER_CHALLENGE)
  {
    SecPkgContext_AuthNtlmServerChallenge* AuthNtlmServerChallenge =
        (SecPkgContext_AuthNtlmServerChallenge*)pBuffer;
 
    if (cbBuffer < sizeof(SecPkgContext_AuthNtlmServerChallenge))
      return SEC_E_INVALID_PARAMETER;
 
    CopyMemory(context->ServerChallenge, AuthNtlmServerChallenge->ServerChallenge, 8);
    return SEC_E_OK;
  }
 
  WLog_ERR(TAG, "TODO: Implement ulAttribute=%08" PRIx32, ulAttribute);
  return SEC_E_UNSUPPORTED_FUNCTION;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_SetContextAttributesA(PCtxtHandle phContext,
                                                            ULONG ulAttribute, void* pBuffer,
                                                            ULONG cbBuffer)
{
  return ntlm_SetContextAttributesW(phContext, ulAttribute, pBuffer, cbBuffer);
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_SetCredentialsAttributesW(PCredHandle phCredential,
                                                                ULONG ulAttribute, void* pBuffer,
                                                                ULONG cbBuffer)
{
  return SEC_E_UNSUPPORTED_FUNCTION;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_SetCredentialsAttributesA(PCredHandle phCredential,
                                                                ULONG ulAttribute, void* pBuffer,
                                                                ULONG cbBuffer)
{
  return SEC_E_UNSUPPORTED_FUNCTION;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_RevertSecurityContext(PCtxtHandle phContext)
{
  return SEC_E_OK;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_EncryptMessage(PCtxtHandle phContext, ULONG fQOP,
                                                     PSecBufferDesc pMessage, ULONG MessageSeqNo)
{
  const UINT32 SeqNo = MessageSeqNo;
  UINT32 value = 0;
  BYTE digest[WINPR_MD5_DIGEST_LENGTH] = { 0 };
  BYTE checksum[8] = { 0 };
  ULONG version = 1;
  PSecBuffer data_buffer = NULL;
  PSecBuffer signature_buffer = NULL;
  NTLM_CONTEXT* context = (NTLM_CONTEXT*)sspi_SecureHandleGetLowerPointer(phContext);
  if (!check_context(context))
    return SEC_E_INVALID_HANDLE;
 
  for (ULONG index = 0; index < pMessage->cBuffers; index++)
  {
    SecBuffer* cur = &pMessage->pBuffers[index];
 
    if (cur->BufferType & SECBUFFER_DATA)
      data_buffer = cur;
    else if (cur->BufferType & SECBUFFER_TOKEN)
      signature_buffer = cur;
  }
 
  if (!data_buffer)
    return SEC_E_INVALID_TOKEN;
 
  if (!signature_buffer)
    return SEC_E_INVALID_TOKEN;
 
  /* Copy original data buffer */
  ULONG length = data_buffer->cbBuffer;
  void* data = malloc(length);
 
  if (!data)
    return SEC_E_INSUFFICIENT_MEMORY;
 
  CopyMemory(data, data_buffer->pvBuffer, length);
  /* Compute the HMAC-MD5 hash of ConcatenationOf(seq_num,data) using the client signing key */
  WINPR_HMAC_CTX* hmac = winpr_HMAC_New();
 
  if (hmac &&
      winpr_HMAC_Init(hmac, WINPR_MD_MD5, context->SendSigningKey, WINPR_MD5_DIGEST_LENGTH))
  {
    Data_Write_UINT32(&value, SeqNo);
    winpr_HMAC_Update(hmac, (void*)&value, 4);
    winpr_HMAC_Update(hmac, data, length);
    winpr_HMAC_Final(hmac, digest, WINPR_MD5_DIGEST_LENGTH);
    winpr_HMAC_Free(hmac);
  }
  else
  {
    winpr_HMAC_Free(hmac);
    free(data);
    return SEC_E_INSUFFICIENT_MEMORY;
  }
 
  /* Encrypt message using with RC4, result overwrites original buffer */
  if ((data_buffer->BufferType & SECBUFFER_READONLY) == 0)
  {
    if (context->confidentiality)
      winpr_RC4_Update(context->SendRc4Seal, length, (BYTE*)data,
                       (BYTE*)data_buffer->pvBuffer);
    else
      CopyMemory(data_buffer->pvBuffer, data, length);
  }
 
#ifdef WITH_DEBUG_NTLM
  WLog_DBG(TAG, "Data Buffer (length = %" PRIuz ")", length);
  winpr_HexDump(TAG, WLOG_DEBUG, data, length);
  WLog_DBG(TAG, "Encrypted Data Buffer (length = %" PRIu32 ")", data_buffer->cbBuffer);
  winpr_HexDump(TAG, WLOG_DEBUG, data_buffer->pvBuffer, data_buffer->cbBuffer);
#endif
  free(data);
  /* RC4-encrypt first 8 bytes of digest */
  winpr_RC4_Update(context->SendRc4Seal, 8, digest, checksum);
  if ((signature_buffer->BufferType & SECBUFFER_READONLY) == 0)
  {
    BYTE* signature = signature_buffer->pvBuffer;
    /* Concatenate version, ciphertext and sequence number to build signature */
    Data_Write_UINT32(signature, version);
    CopyMemory(&signature[4], (void*)checksum, 8);
    Data_Write_UINT32(&signature[12], SeqNo);
  }
  context->SendSeqNum++;
#ifdef WITH_DEBUG_NTLM
  WLog_DBG(TAG, "Signature (length = %" PRIu32 ")", signature_buffer->cbBuffer);
  winpr_HexDump(TAG, WLOG_DEBUG, signature_buffer->pvBuffer, signature_buffer->cbBuffer);
#endif
  return SEC_E_OK;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_DecryptMessage(PCtxtHandle phContext, PSecBufferDesc pMessage,
                                                     ULONG MessageSeqNo, PULONG pfQOP)
{
  const UINT32 SeqNo = (UINT32)MessageSeqNo;
  UINT32 value = 0;
  BYTE digest[WINPR_MD5_DIGEST_LENGTH] = { 0 };
  BYTE checksum[8] = { 0 };
  UINT32 version = 1;
  BYTE expected_signature[WINPR_MD5_DIGEST_LENGTH] = { 0 };
  PSecBuffer data_buffer = NULL;
  PSecBuffer signature_buffer = NULL;
  NTLM_CONTEXT* context = (NTLM_CONTEXT*)sspi_SecureHandleGetLowerPointer(phContext);
  if (!check_context(context))
    return SEC_E_INVALID_HANDLE;
 
  for (ULONG index = 0; index < pMessage->cBuffers; index++)
  {
    if (pMessage->pBuffers[index].BufferType == SECBUFFER_DATA)
      data_buffer = &pMessage->pBuffers[index];
    else if (pMessage->pBuffers[index].BufferType == SECBUFFER_TOKEN)
      signature_buffer = &pMessage->pBuffers[index];
  }
 
  if (!data_buffer)
    return SEC_E_INVALID_TOKEN;
 
  if (!signature_buffer)
    return SEC_E_INVALID_TOKEN;
 
  /* Copy original data buffer */
  const ULONG length = data_buffer->cbBuffer;
  void* data = malloc(length);
 
  if (!data)
    return SEC_E_INSUFFICIENT_MEMORY;
 
  CopyMemory(data, data_buffer->pvBuffer, length);
 
  /* Decrypt message using with RC4, result overwrites original buffer */
 
  if (context->confidentiality)
    winpr_RC4_Update(context->RecvRc4Seal, length, (BYTE*)data, (BYTE*)data_buffer->pvBuffer);
  else
    CopyMemory(data_buffer->pvBuffer, data, length);
 
  /* Compute the HMAC-MD5 hash of ConcatenationOf(seq_num,data) using the client signing key */
  WINPR_HMAC_CTX* hmac = winpr_HMAC_New();
 
  if (hmac &&
      winpr_HMAC_Init(hmac, WINPR_MD_MD5, context->RecvSigningKey, WINPR_MD5_DIGEST_LENGTH))
  {
    Data_Write_UINT32(&value, SeqNo);
    winpr_HMAC_Update(hmac, (void*)&value, 4);
    winpr_HMAC_Update(hmac, data_buffer->pvBuffer, data_buffer->cbBuffer);
    winpr_HMAC_Final(hmac, digest, WINPR_MD5_DIGEST_LENGTH);
    winpr_HMAC_Free(hmac);
  }
  else
  {
    winpr_HMAC_Free(hmac);
    free(data);
    return SEC_E_INSUFFICIENT_MEMORY;
  }
 
#ifdef WITH_DEBUG_NTLM
  WLog_DBG(TAG, "Encrypted Data Buffer (length = %" PRIuz ")", length);
  winpr_HexDump(TAG, WLOG_DEBUG, data, length);
  WLog_DBG(TAG, "Data Buffer (length = %" PRIu32 ")", data_buffer->cbBuffer);
  winpr_HexDump(TAG, WLOG_DEBUG, data_buffer->pvBuffer, data_buffer->cbBuffer);
#endif
  free(data);
  /* RC4-encrypt first 8 bytes of digest */
  winpr_RC4_Update(context->RecvRc4Seal, 8, digest, checksum);
  /* Concatenate version, ciphertext and sequence number to build signature */
  Data_Write_UINT32(expected_signature, version);
  CopyMemory(&expected_signature[4], (void*)checksum, 8);
  Data_Write_UINT32(&expected_signature[12], SeqNo);
  context->RecvSeqNum++;
 
  if (memcmp(signature_buffer->pvBuffer, expected_signature, 16) != 0)
  {
    /* signature verification failed! */
    WLog_ERR(TAG, "signature verification failed, something nasty is going on!");
#ifdef WITH_DEBUG_NTLM
    WLog_ERR(TAG, "Expected Signature:");
    winpr_HexDump(TAG, WLOG_ERROR, expected_signature, 16);
    WLog_ERR(TAG, "Actual Signature:");
    winpr_HexDump(TAG, WLOG_ERROR, (BYTE*)signature_buffer->pvBuffer, 16);
#endif
    return SEC_E_MESSAGE_ALTERED;
  }
 
  return SEC_E_OK;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_MakeSignature(PCtxtHandle phContext, ULONG fQOP,
                                                    PSecBufferDesc pMessage, ULONG MessageSeqNo)
{
  PSecBuffer data_buffer = NULL;
  PSecBuffer sig_buffer = NULL;
  UINT32 seq_no = 0;
  BYTE digest[WINPR_MD5_DIGEST_LENGTH] = { 0 };
  BYTE checksum[8] = { 0 };
 
  NTLM_CONTEXT* context = sspi_SecureHandleGetLowerPointer(phContext);
  if (!check_context(context))
    return SEC_E_INVALID_HANDLE;
 
  for (ULONG i = 0; i < pMessage->cBuffers; i++)
  {
    if (pMessage->pBuffers[i].BufferType == SECBUFFER_DATA)
      data_buffer = &pMessage->pBuffers[i];
    else if (pMessage->pBuffers[i].BufferType == SECBUFFER_TOKEN)
      sig_buffer = &pMessage->pBuffers[i];
  }
 
  if (!data_buffer || !sig_buffer)
    return SEC_E_INVALID_TOKEN;
 
  WINPR_HMAC_CTX* hmac = winpr_HMAC_New();
 
  if (!winpr_HMAC_Init(hmac, WINPR_MD_MD5, context->SendSigningKey, WINPR_MD5_DIGEST_LENGTH))
  {
    winpr_HMAC_Free(hmac);
    return SEC_E_INTERNAL_ERROR;
  }
 
  Data_Write_UINT32(&seq_no, MessageSeqNo);
  winpr_HMAC_Update(hmac, (BYTE*)&seq_no, 4);
  winpr_HMAC_Update(hmac, data_buffer->pvBuffer, data_buffer->cbBuffer);
  winpr_HMAC_Final(hmac, digest, WINPR_MD5_DIGEST_LENGTH);
  winpr_HMAC_Free(hmac);
 
  winpr_RC4_Update(context->SendRc4Seal, 8, digest, checksum);
 
  BYTE* signature = sig_buffer->pvBuffer;
  Data_Write_UINT32(signature, 1L);
  CopyMemory(&signature[4], checksum, 8);
  Data_Write_UINT32(&signature[12], seq_no);
  sig_buffer->cbBuffer = 16;
 
  return SEC_E_OK;
}
 
static SECURITY_STATUS SEC_ENTRY ntlm_VerifySignature(PCtxtHandle phContext,
                                                      PSecBufferDesc pMessage, ULONG MessageSeqNo,
                                                      PULONG pfQOP)
{
  PSecBuffer data_buffer = NULL;
  PSecBuffer sig_buffer = NULL;
  UINT32 seq_no = 0;
  BYTE digest[WINPR_MD5_DIGEST_LENGTH] = { 0 };
  BYTE checksum[8] = { 0 };
  BYTE signature[16] = { 0 };
 
  NTLM_CONTEXT* context = sspi_SecureHandleGetLowerPointer(phContext);
  if (!check_context(context))
    return SEC_E_INVALID_HANDLE;
 
  for (ULONG i = 0; i < pMessage->cBuffers; i++)
  {
    if (pMessage->pBuffers[i].BufferType == SECBUFFER_DATA)
      data_buffer = &pMessage->pBuffers[i];
    else if (pMessage->pBuffers[i].BufferType == SECBUFFER_TOKEN)
      sig_buffer = &pMessage->pBuffers[i];
  }
 
  if (!data_buffer || !sig_buffer)
    return SEC_E_INVALID_TOKEN;
 
  WINPR_HMAC_CTX* hmac = winpr_HMAC_New();
 
  if (!winpr_HMAC_Init(hmac, WINPR_MD_MD5, context->RecvSigningKey, WINPR_MD5_DIGEST_LENGTH))
  {
    winpr_HMAC_Free(hmac);
    return SEC_E_INTERNAL_ERROR;
  }
 
  Data_Write_UINT32(&seq_no, MessageSeqNo);
  winpr_HMAC_Update(hmac, (BYTE*)&seq_no, 4);
  winpr_HMAC_Update(hmac, data_buffer->pvBuffer, data_buffer->cbBuffer);
  winpr_HMAC_Final(hmac, digest, WINPR_MD5_DIGEST_LENGTH);
  winpr_HMAC_Free(hmac);
 
  winpr_RC4_Update(context->RecvRc4Seal, 8, digest, checksum);
 
  Data_Write_UINT32(signature, 1L);
  CopyMemory(&signature[4], checksum, 8);
  Data_Write_UINT32(&signature[12], seq_no);
 
  if (memcmp(sig_buffer->pvBuffer, signature, 16) != 0)
    return SEC_E_MESSAGE_ALTERED;
 
  return SEC_E_OK;
}
 
const SecurityFunctionTableA NTLM_SecurityFunctionTableA = {
  3,                                /* dwVersion */
  NULL,                             /* EnumerateSecurityPackages */
  ntlm_QueryCredentialsAttributesA, /* QueryCredentialsAttributes */
  ntlm_AcquireCredentialsHandleA,   /* AcquireCredentialsHandle */
  ntlm_FreeCredentialsHandle,       /* FreeCredentialsHandle */
  NULL,                             /* Reserved2 */
  ntlm_InitializeSecurityContextA,  /* InitializeSecurityContext */
  ntlm_AcceptSecurityContext,       /* AcceptSecurityContext */
  NULL,                             /* CompleteAuthToken */
  ntlm_DeleteSecurityContext,       /* DeleteSecurityContext */
  NULL,                             /* ApplyControlToken */
  ntlm_QueryContextAttributesA,     /* QueryContextAttributes */
  ntlm_ImpersonateSecurityContext,  /* ImpersonateSecurityContext */
  ntlm_RevertSecurityContext,       /* RevertSecurityContext */
  ntlm_MakeSignature,               /* MakeSignature */
  ntlm_VerifySignature,             /* VerifySignature */
  NULL,                             /* FreeContextBuffer */
  NULL,                             /* QuerySecurityPackageInfo */
  NULL,                             /* Reserved3 */
  NULL,                             /* Reserved4 */
  NULL,                             /* ExportSecurityContext */
  NULL,                             /* ImportSecurityContext */
  NULL,                             /* AddCredentials */
  NULL,                             /* Reserved8 */
  NULL,                             /* QuerySecurityContextToken */
  ntlm_EncryptMessage,              /* EncryptMessage */
  ntlm_DecryptMessage,              /* DecryptMessage */
  ntlm_SetContextAttributesA,       /* SetContextAttributes */
  ntlm_SetCredentialsAttributesA,   /* SetCredentialsAttributes */
};
 
const SecurityFunctionTableW NTLM_SecurityFunctionTableW = {
  3,                                /* dwVersion */
  NULL,                             /* EnumerateSecurityPackages */
  ntlm_QueryCredentialsAttributesW, /* QueryCredentialsAttributes */
  ntlm_AcquireCredentialsHandleW,   /* AcquireCredentialsHandle */
  ntlm_FreeCredentialsHandle,       /* FreeCredentialsHandle */
  NULL,                             /* Reserved2 */
  ntlm_InitializeSecurityContextW,  /* InitializeSecurityContext */
  ntlm_AcceptSecurityContext,       /* AcceptSecurityContext */
  NULL,                             /* CompleteAuthToken */
  ntlm_DeleteSecurityContext,       /* DeleteSecurityContext */
  NULL,                             /* ApplyControlToken */
  ntlm_QueryContextAttributesW,     /* QueryContextAttributes */
  ntlm_ImpersonateSecurityContext,  /* ImpersonateSecurityContext */
  ntlm_RevertSecurityContext,       /* RevertSecurityContext */
  ntlm_MakeSignature,               /* MakeSignature */
  ntlm_VerifySignature,             /* VerifySignature */
  NULL,                             /* FreeContextBuffer */
  NULL,                             /* QuerySecurityPackageInfo */
  NULL,                             /* Reserved3 */
  NULL,                             /* Reserved4 */
  NULL,                             /* ExportSecurityContext */
  NULL,                             /* ImportSecurityContext */
  NULL,                             /* AddCredentials */
  NULL,                             /* Reserved8 */
  NULL,                             /* QuerySecurityContextToken */
  ntlm_EncryptMessage,              /* EncryptMessage */
  ntlm_DecryptMessage,              /* DecryptMessage */
  ntlm_SetContextAttributesW,       /* SetContextAttributes */
  ntlm_SetCredentialsAttributesW,   /* SetCredentialsAttributes */
};
 
const SecPkgInfoA NTLM_SecPkgInfoA = {
  0x00082B37,             /* fCapabilities */
  1,                      /* wVersion */
  0x000A,                 /* wRPCID */
  0x00000B48,             /* cbMaxToken */
  "NTLM",                 /* Name */
  "NTLM Security Package" /* Comment */
};
 
static WCHAR NTLM_SecPkgInfoW_NameBuffer[32] = { 0 };
static WCHAR NTLM_SecPkgInfoW_CommentBuffer[32] = { 0 };
 
const SecPkgInfoW NTLM_SecPkgInfoW = {
  0x00082B37,                    /* fCapabilities */
  1,                             /* wVersion */
  0x000A,                        /* wRPCID */
  0x00000B48,                    /* cbMaxToken */
  NTLM_SecPkgInfoW_NameBuffer,   /* Name */
  NTLM_SecPkgInfoW_CommentBuffer /* Comment */
};
 
char* ntlm_negotiate_flags_string(char* buffer, size_t size, UINT32 flags)
{
  if (!buffer || (size == 0))
    return buffer;
 
  (void)_snprintf(buffer, size, "[0x%08" PRIx32 "] ", flags);
 
  for (int x = 0; x < 31; x++)
  {
    const UINT32 mask = 1 << x;
    size_t len = strnlen(buffer, size);
    if (flags & mask)
    {
      const char* str = ntlm_get_negotiate_string(mask);
      const size_t flen = strlen(str);
 
      if ((len > 0) && (buffer[len - 1] != ' '))
      {
        if (size - len < 1)
          break;
        winpr_str_append("|", buffer, size, NULL);
        len++;
      }
 
      if (size - len < flen)
        break;
      winpr_str_append(str, buffer, size, NULL);
    }
  }
 
  return buffer;
}
 
const char* ntlm_message_type_string(UINT32 messageType)
{
  switch (messageType)
  {
    case MESSAGE_TYPE_NEGOTIATE:
      return "MESSAGE_TYPE_NEGOTIATE";
    case MESSAGE_TYPE_CHALLENGE:
      return "MESSAGE_TYPE_CHALLENGE";
    case MESSAGE_TYPE_AUTHENTICATE:
      return "MESSAGE_TYPE_AUTHENTICATE";
    default:
      return "MESSAGE_TYPE_UNKNOWN";
  }
}
 
const char* ntlm_state_string(NTLM_STATE state)
{
  switch (state)
  {
    case NTLM_STATE_INITIAL:
      return "NTLM_STATE_INITIAL";
    case NTLM_STATE_NEGOTIATE:
      return "NTLM_STATE_NEGOTIATE";
    case NTLM_STATE_CHALLENGE:
      return "NTLM_STATE_CHALLENGE";
    case NTLM_STATE_AUTHENTICATE:
      return "NTLM_STATE_AUTHENTICATE";
    case NTLM_STATE_FINAL:
      return "NTLM_STATE_FINAL";
    default:
      return "NTLM_STATE_UNKNOWN";
  }
}
void ntlm_change_state(NTLM_CONTEXT* ntlm, NTLM_STATE state)
{
  WINPR_ASSERT(ntlm);
  WLog_DBG(TAG, "change state from %s to %s", ntlm_state_string(ntlm->state),
           ntlm_state_string(state));
  ntlm->state = state;
}
 
NTLM_STATE ntlm_get_state(NTLM_CONTEXT* ntlm)
{
  WINPR_ASSERT(ntlm);
  return ntlm->state;
}
 
BOOL ntlm_reset_cipher_state(PSecHandle phContext)
{
  NTLM_CONTEXT* context = sspi_SecureHandleGetLowerPointer(phContext);
 
  if (context)
  {
    check_context(context);
    winpr_RC4_Free(context->SendRc4Seal);
    winpr_RC4_Free(context->RecvRc4Seal);
    context->SendRc4Seal = winpr_RC4_New(context->RecvSealingKey, 16);
    context->RecvRc4Seal = winpr_RC4_New(context->SendSealingKey, 16);
 
    if (!context->SendRc4Seal)
    {
      WLog_ERR(TAG, "Failed to allocate context->SendRc4Seal");
      return FALSE;
    }
    if (!context->RecvRc4Seal)
    {
      WLog_ERR(TAG, "Failed to allocate context->RecvRc4Seal");
      return FALSE;
    }
  }
 
  return TRUE;
}
 
BOOL NTLM_init(void)
{
  InitializeConstWCharFromUtf8(NTLM_SecPkgInfoA.Name, NTLM_SecPkgInfoW_NameBuffer,
                               ARRAYSIZE(NTLM_SecPkgInfoW_NameBuffer));
  InitializeConstWCharFromUtf8(NTLM_SecPkgInfoA.Comment, NTLM_SecPkgInfoW_CommentBuffer,
                               ARRAYSIZE(NTLM_SecPkgInfoW_CommentBuffer));
 
  return TRUE;
}