curl/lib/system_win32.c

/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) Steve Holme, <steve_holme@hotmail.com>.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * SPDX-License-Identifier: curl
 *
 ***************************************************************************/

#include "curl_setup.h"

#if defined(_WIN32)

#include <curl/curl.h>
#include "system_win32.h"
#include "version_win32.h"
#include "curl_sspi.h"
#include "warnless.h"

/* The last #include files should be: */
#include "curl_memory.h"
#include "memdebug.h"

LARGE_INTEGER Curl_freq;
bool Curl_isVistaOrGreater;
bool Curl_isWindows8OrGreater;

/* Handle of iphlpapp.dll */
static HMODULE s_hIpHlpApiDll = NULL;

/* Function pointers */
IF_NAMETOINDEX_FN Curl_if_nametoindex = NULL;
FREEADDRINFOEXW_FN Curl_FreeAddrInfoExW = NULL;
GETADDRINFOEXCANCEL_FN Curl_GetAddrInfoExCancel = NULL;
GETADDRINFOEXW_FN Curl_GetAddrInfoExW = NULL;

/* Curl_win32_init() performs win32 global initialization */
CURLcode Curl_win32_init(long flags)
{
#ifdef USE_WINSOCK
  HMODULE ws2_32Dll;
#endif
  /* CURL_GLOBAL_WIN32 controls the *optional* part of the initialization which
     is just for Winsock at the moment. Any required win32 initialization
     should take place after this block. */
  if(flags & CURL_GLOBAL_WIN32) {
#ifdef USE_WINSOCK
    WORD wVersionRequested;
    WSADATA wsaData;
    int res;

    wVersionRequested = MAKEWORD(2, 2);
    res = WSAStartup(wVersionRequested, &wsaData);

    if(res)
      /* Tell the user that we couldn't find a usable */
      /* winsock.dll.     */
      return CURLE_FAILED_INIT;

    /* Confirm that the Windows Sockets DLL supports what we need.*/
    /* Note that if the DLL supports versions greater */
    /* than wVersionRequested, it will still return */
    /* wVersionRequested in wVersion. wHighVersion contains the */
    /* highest supported version. */

    if(LOBYTE(wsaData.wVersion) != LOBYTE(wVersionRequested) ||
       HIBYTE(wsaData.wVersion) != HIBYTE(wVersionRequested) ) {
      /* Tell the user that we couldn't find a usable */

      /* winsock.dll. */
      WSACleanup();
      return CURLE_FAILED_INIT;
    }
    /* The Windows Sockets DLL is acceptable. Proceed. */
#elif defined(USE_LWIPSOCK)
    lwip_init();
#endif
  } /* CURL_GLOBAL_WIN32 */

#ifdef USE_WINDOWS_SSPI
  {
    CURLcode result = Curl_sspi_global_init();
    if(result)
      return result;
  }
#endif

  s_hIpHlpApiDll = Curl_load_library(TEXT("iphlpapi.dll"));
  if(s_hIpHlpApiDll) {
    /* Get the address of the if_nametoindex function */
    IF_NAMETOINDEX_FN pIfNameToIndex =
      CURLX_FUNCTION_CAST(IF_NAMETOINDEX_FN,
                          (GetProcAddress(s_hIpHlpApiDll, "if_nametoindex")));

    if(pIfNameToIndex)
      Curl_if_nametoindex = pIfNameToIndex;
  }

#ifdef USE_WINSOCK
#ifdef CURL_WINDOWS_APP
  ws2_32Dll = Curl_load_library(TEXT("ws2_32.dll"));
#else
  ws2_32Dll = GetModuleHandleA("ws2_32");
#endif
  if(ws2_32Dll) {
    Curl_FreeAddrInfoExW = CURLX_FUNCTION_CAST(FREEADDRINFOEXW_FN,
      GetProcAddress(ws2_32Dll, "FreeAddrInfoExW"));
    Curl_GetAddrInfoExCancel = CURLX_FUNCTION_CAST(GETADDRINFOEXCANCEL_FN,
      GetProcAddress(ws2_32Dll, "GetAddrInfoExCancel"));
    Curl_GetAddrInfoExW = CURLX_FUNCTION_CAST(GETADDRINFOEXW_FN,
      GetProcAddress(ws2_32Dll, "GetAddrInfoExW"));
  }
#endif

  /* curlx_verify_windows_version must be called during init at least once
     because it has its own initialization routine. */
  if(curlx_verify_windows_version(6, 0, 0, PLATFORM_WINNT,
                                  VERSION_GREATER_THAN_EQUAL)) {
    Curl_isVistaOrGreater = TRUE;
  }
  else
    Curl_isVistaOrGreater = FALSE;

  if(curlx_verify_windows_version(6, 2, 0, PLATFORM_WINNT,
                                  VERSION_GREATER_THAN_EQUAL)) {
    Curl_isWindows8OrGreater = TRUE;
  }
  else
    Curl_isWindows8OrGreater = FALSE;

  QueryPerformanceFrequency(&Curl_freq);
  return CURLE_OK;
}

/* Curl_win32_cleanup() is the opposite of Curl_win32_init() */
void Curl_win32_cleanup(long init_flags)
{
  Curl_FreeAddrInfoExW = NULL;
  Curl_GetAddrInfoExCancel = NULL;
  Curl_GetAddrInfoExW = NULL;
  if(s_hIpHlpApiDll) {
    FreeLibrary(s_hIpHlpApiDll);
    s_hIpHlpApiDll = NULL;
    Curl_if_nametoindex = NULL;
  }

#ifdef USE_WINDOWS_SSPI
  Curl_sspi_global_cleanup();
#endif

  if(init_flags & CURL_GLOBAL_WIN32) {
#ifdef USE_WINSOCK
    WSACleanup();
#endif
  }
}

#if !defined(LOAD_WITH_ALTERED_SEARCH_PATH)
#define LOAD_WITH_ALTERED_SEARCH_PATH  0x00000008
#endif

#if !defined(LOAD_LIBRARY_SEARCH_SYSTEM32)
#define LOAD_LIBRARY_SEARCH_SYSTEM32   0x00000800
#endif

/* We use our own typedef here since some headers might lack these */
typedef HMODULE (APIENTRY *LOADLIBRARYEX_FN)(LPCTSTR, HANDLE, DWORD);

/* See function definitions in winbase.h */
#ifdef UNICODE
#  ifdef _WIN32_WCE
#    define LOADLIBARYEX  L"LoadLibraryExW"
#  else
#    define LOADLIBARYEX  "LoadLibraryExW"
#  endif
#else
#  define LOADLIBARYEX    "LoadLibraryExA"
#endif

/*
 * Curl_load_library()
 *
 * This is used to dynamically load DLLs using the most secure method available
 * for the version of Windows that we are running on.
 *
 * Parameters:
 *
 * filename  [in] - The filename or full path of the DLL to load. If only the
 *                  filename is passed then the DLL will be loaded from the
 *                  Windows system directory.
 *
 * Returns the handle of the module on success; otherwise NULL.
 */
HMODULE Curl_load_library(LPCTSTR filename)
{
#ifndef CURL_WINDOWS_APP
  HMODULE hModule = NULL;
  LOADLIBRARYEX_FN pLoadLibraryEx = NULL;

  /* Get a handle to kernel32 so we can access it's functions at runtime */
  HMODULE hKernel32 = GetModuleHandle(TEXT("kernel32"));
  if(!hKernel32)
    return NULL;

  /* Attempt to find LoadLibraryEx() which is only available on Windows 2000
     and above */
  pLoadLibraryEx =
    CURLX_FUNCTION_CAST(LOADLIBRARYEX_FN,
                        (GetProcAddress(hKernel32, LOADLIBARYEX)));

  /* Detect if there's already a path in the filename and load the library if
     there is. Note: Both back slashes and forward slashes have been supported
     since the earlier days of DOS at an API level although they are not
     supported by command prompt */
  if(_tcspbrk(filename, TEXT("\\/"))) {
    /** !checksrc! disable BANNEDFUNC 1 **/
    hModule = pLoadLibraryEx ?
      pLoadLibraryEx(filename, NULL, LOAD_WITH_ALTERED_SEARCH_PATH) :
      LoadLibrary(filename);
  }
  /* Detect if KB2533623 is installed, as LOAD_LIBRARY_SEARCH_SYSTEM32 is only
     supported on Windows Vista, Windows Server 2008, Windows 7 and Windows
     Server 2008 R2 with this patch or natively on Windows 8 and above */
  else if(pLoadLibraryEx && GetProcAddress(hKernel32, "AddDllDirectory")) {
    /* Load the DLL from the Windows system directory */
    hModule = pLoadLibraryEx(filename, NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
  }
  else {
    /* Attempt to get the Windows system path */
    UINT systemdirlen = GetSystemDirectory(NULL, 0);
    if(systemdirlen) {
      /* Allocate space for the full DLL path (Room for the null terminator
         is included in systemdirlen) */
      size_t filenamelen = _tcslen(filename);
      TCHAR *path = malloc(sizeof(TCHAR) * (systemdirlen + 1 + filenamelen));
      if(path && GetSystemDirectory(path, systemdirlen)) {
        /* Calculate the full DLL path */
        _tcscpy(path + _tcslen(path), TEXT("\\"));
        _tcscpy(path + _tcslen(path), filename);

        /* Load the DLL from the Windows system directory */
        /** !checksrc! disable BANNEDFUNC 1 **/
        hModule = pLoadLibraryEx ?
          pLoadLibraryEx(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH) :
          LoadLibrary(path);

      }
      free(path);
    }
  }
  return hModule;
#else
  /* the Universal Windows Platform (UWP) can't do this */
  (void)filename;
  return NULL;
#endif
}

bool Curl_win32_impersonating(void)
{
#ifndef CURL_WINDOWS_APP
  HANDLE token = NULL;
  if(OpenThreadToken(GetCurrentThread(), TOKEN_QUERY, TRUE, &token)) {
    CloseHandle(token);
    return TRUE;
  }
#endif
  return FALSE;
}

#endif /* _WIN32 */