Imported Upstream version 2.3.10upstream/2.3.10

1 files changed, 334 insertions, 1 deletions

diff --git a/src/openvpn/win32.c b/src/openvpn/win32.c
index f35c96b..6c6ac4c 100644
--- a/src/openvpn/win32.c
+++ b/src/openvpn/win32.c
@@ -46,6 +46,34 @@
 
 #include "memdbg.h"
 
+#include "win32_wfp.h"
+
+#ifdef HAVE_VERSIONHELPERS_H
+#include <versionhelpers.h>
+#else
+#include "compat-versionhelpers.h"
+#endif
+
+/* WFP function pointers. Initialized in win_wfp_init_funcs() */
+func_ConvertInterfaceIndexToLuid ConvertInterfaceIndexToLuid = NULL;
+func_FwpmEngineOpen0 FwpmEngineOpen0 = NULL;
+func_FwpmEngineClose0 FwpmEngineClose0 = NULL;
+func_FwpmFilterAdd0 FwpmFilterAdd0 = NULL;
+func_FwpmSubLayerAdd0 FwpmSubLayerAdd0 = NULL;
+func_FwpmSubLayerDeleteByKey0 FwpmSubLayerDeleteByKey0 = NULL;
+func_FwpmFreeMemory0 FwpmFreeMemory0 = NULL;
+func_FwpmGetAppIdFromFileName0 FwpmGetAppIdFromFileName0 = NULL;
+
+/*
+ * WFP firewall name.
+ */
+WCHAR * FIREWALL_NAME = L"OpenVPN"; /* GLOBAL */
+
+/*
+ * WFP handle and GUID.
+ */
+static HANDLE m_hEngineHandle = NULL; /* GLOBAL */
+
 /*
  * Windows internal socket API state (opaque).
  */
@@ -324,6 +352,53 @@ net_event_win32_close (struct net_event_win32 *ne)
  * (2) Service mode -- map Windows event object to SIGTERM
  */
 
+static void
+win_trigger_event(struct win32_signal *ws)
+{
+  if (ws->mode == WSO_MODE_SERVICE && HANDLE_DEFINED(ws->in.read))
+    SetEvent (ws->in.read);
+  else /* generate a key-press event */
+    {
+      DWORD tmp;
+      INPUT_RECORD ir;
+      HANDLE stdin_handle = GetStdHandle(STD_INPUT_HANDLE);
+
+      CLEAR(ir);
+      ir.EventType = KEY_EVENT;
+      ir.Event.KeyEvent.bKeyDown = true;
+      if (!stdin_handle || !WriteConsoleInput(stdin_handle, &ir, 1, &tmp))
+        msg(M_WARN|M_ERRNO, "WARN: win_trigger_event: WriteConsoleInput");
+    }
+}
+
+/*
+ * Callback to handle console ctrl events
+ */
+static bool WINAPI
+win_ctrl_handler (DWORD signum)
+{
+  msg(D_LOW, "win_ctrl_handler: signal received (code=%lu)", (unsigned long) signum);
+
+  if (siginfo_static.signal_received == SIGTERM)
+     return true;
+
+  switch (signum)
+    {
+    case CTRL_C_EVENT:
+    case CTRL_BREAK_EVENT:
+      throw_signal(SIGTERM);
+      /* trigget the win32_signal to interrupt the event loop */
+      win_trigger_event(&win32_signal);
+      return true;
+      break;
+    default:
+      msg(D_LOW, "win_ctrl_handler: signal (code=%lu) not handled", (unsigned long) signum);
+      break;
+    }
+  /* pass all other signals to the next handler */
+  return false;
+}
+
 void
 win32_signal_clear (struct win32_signal *ws)
 {
@@ -403,6 +478,9 @@ win32_signal_open (struct win32_signal *ws,
 	    ws->mode = WSO_MODE_SERVICE;
 	}
     }
+    /* set the ctrl handler in both console and service modes */
+    if (!SetConsoleCtrlHandler ((PHANDLER_ROUTINE) win_ctrl_handler, true))
+       msg (M_WARN|M_ERRNO, "WARN: SetConsoleCtrlHandler failed");
 }
 
 static bool
@@ -512,6 +590,9 @@ win32_signal_get (struct win32_signal *ws)
 	    case 0x3E: /* F4 -> TERM */
 	      ret = SIGTERM;
 	      break;
+           case 0x03: /* CTRL-C -> TERM */
+             ret = SIGTERM;
+             break;
 	    }
 	}
       if (ret)
@@ -763,7 +844,12 @@ win_safe_filename (const char *fn)
 static char *
 env_block (const struct env_set *es)
 {
-  char * force_path = "PATH=C:\\Windows\\System32;C:\\WINDOWS;C:\\WINDOWS\\System32\\Wbem";
+  char force_path[256];
+  char *sysroot = get_win_sys_path();
+
+  if (!openvpn_snprintf(force_path, sizeof(force_path), "PATH=%s\\System32;%s;%s\\System32\\Wbem",
+                        sysroot, sysroot, sysroot))
+    msg(M_WARN, "env_block: default path truncated to %s", force_path);
 
   if (es)
     {
@@ -1019,4 +1105,251 @@ win_get_tempdir()
   WideCharToMultiByte (CP_UTF8, 0, wtmpdir, -1, tmpdir, sizeof (tmpdir), NULL, NULL);
   return tmpdir;
 }
+
+bool
+win_wfp_init_funcs ()
+{
+  /* Initialize all WFP-related function pointers */
+  HMODULE iphlpapiHandle;
+  HMODULE fwpuclntHandle;
+
+  iphlpapiHandle = LoadLibrary("iphlpapi.dll");
+  if (iphlpapiHandle == NULL)
+  {
+    msg (M_NONFATAL, "Can't load iphlpapi.dll");
+    return false;
+  }
+
+  fwpuclntHandle = LoadLibrary("fwpuclnt.dll");
+  if (fwpuclntHandle == NULL)
+  {
+    msg (M_NONFATAL, "Can't load fwpuclnt.dll");
+    return false;
+  }
+
+  ConvertInterfaceIndexToLuid = (func_ConvertInterfaceIndexToLuid)GetProcAddress(iphlpapiHandle, "ConvertInterfaceIndexToLuid");
+  FwpmFilterAdd0 = (func_FwpmFilterAdd0)GetProcAddress(fwpuclntHandle, "FwpmFilterAdd0");
+  FwpmEngineOpen0 = (func_FwpmEngineOpen0)GetProcAddress(fwpuclntHandle, "FwpmEngineOpen0");
+  FwpmEngineClose0 = (func_FwpmEngineClose0)GetProcAddress(fwpuclntHandle, "FwpmEngineClose0");
+  FwpmSubLayerAdd0 = (func_FwpmSubLayerAdd0)GetProcAddress(fwpuclntHandle, "FwpmSubLayerAdd0");
+  FwpmSubLayerDeleteByKey0 = (func_FwpmSubLayerDeleteByKey0)GetProcAddress(fwpuclntHandle, "FwpmSubLayerDeleteByKey0");
+  FwpmFreeMemory0 = (func_FwpmFreeMemory0)GetProcAddress(fwpuclntHandle, "FwpmFreeMemory0");
+  FwpmGetAppIdFromFileName0 = (func_FwpmGetAppIdFromFileName0)GetProcAddress(fwpuclntHandle, "FwpmGetAppIdFromFileName0");
+
+  if (!ConvertInterfaceIndexToLuid ||
+      !FwpmFilterAdd0 ||
+      !FwpmEngineOpen0 ||
+      !FwpmEngineClose0 ||
+      !FwpmSubLayerAdd0 ||
+      !FwpmSubLayerDeleteByKey0 ||
+      !FwpmFreeMemory0 ||
+      !FwpmGetAppIdFromFileName0)
+  {
+    msg (M_NONFATAL, "Can't get address for all WFP-related procedures.");
+    return false;
+  }
+
+  return true;
+}
+
+bool
+win_wfp_add_filter (HANDLE engineHandle,
+                    const FWPM_FILTER0 *filter,
+                    PSECURITY_DESCRIPTOR sd,
+                    UINT64 *id)
+{
+    if (FwpmFilterAdd0(engineHandle, filter, sd, id) != ERROR_SUCCESS)
+    {
+        msg (M_NONFATAL, "Can't add WFP filter");
+        return false;
+    }
+    return true;
+}
+
+bool
+win_wfp_block_dns (const NET_IFINDEX index)
+{
+    FWPM_SESSION0 session = {0};
+    FWPM_SUBLAYER0 SubLayer = {0};
+    NET_LUID tapluid;
+    UINT64 filterid;
+    WCHAR openvpnpath[MAX_PATH];
+    FWP_BYTE_BLOB *openvpnblob = NULL;
+    FWPM_FILTER0 Filter = {0};
+    FWPM_FILTER_CONDITION0 Condition[2] = {0};
+
+    /* Add temporary filters which don't survive reboots or crashes. */
+    session.flags = FWPM_SESSION_FLAG_DYNAMIC;
+
+    dmsg (D_LOW, "Opening WFP engine");
+
+    if (FwpmEngineOpen0(NULL, RPC_C_AUTHN_WINNT, NULL, &session, &m_hEngineHandle) != ERROR_SUCCESS)
+    {
+        msg (M_NONFATAL, "Can't open WFP engine");
+        return false;
+    }
+
+    if (UuidCreate(&SubLayer.subLayerKey) != NO_ERROR)
+        return false;
+
+    /* Populate packet filter layer information. */
+    SubLayer.displayData.name = FIREWALL_NAME;
+    SubLayer.displayData.description = FIREWALL_NAME;
+    SubLayer.flags = 0;
+    SubLayer.weight = 0x100;
+
+    /* Add packet filter to our interface. */
+    dmsg (D_LOW, "Adding WFP sublayer");
+    if (FwpmSubLayerAdd0(m_hEngineHandle, &SubLayer, NULL) != ERROR_SUCCESS)
+    {
+        msg (M_NONFATAL, "Can't add WFP sublayer");
+        return false;
+    }
+
+    dmsg (D_LOW, "Blocking DNS using WFP");
+    if (ConvertInterfaceIndexToLuid(index, &tapluid) != NO_ERROR)
+    {
+        msg (M_NONFATAL, "Can't convert interface index to LUID");
+        return false;
+    }
+    dmsg (D_LOW, "Tap Luid: %I64d", tapluid.Value);
+
+    /* Get OpenVPN path. */
+    GetModuleFileNameW(NULL, openvpnpath, MAX_PATH);
+
+    if (FwpmGetAppIdFromFileName0(openvpnpath, &openvpnblob) != ERROR_SUCCESS)
+        return false;
+
+    /* Prepare filter. */
+    Filter.subLayerKey = SubLayer.subLayerKey;
+    Filter.displayData.name = FIREWALL_NAME;
+    Filter.weight.type = FWP_EMPTY;
+    Filter.filterCondition = Condition;
+    Filter.numFilterConditions = 2;
+
+    /* First filter. Block IPv4 DNS queries except from OpenVPN itself. */
+    Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V4;
+    Filter.action.type = FWP_ACTION_BLOCK;
+
+    Condition[0].fieldKey = FWPM_CONDITION_IP_REMOTE_PORT;
+    Condition[0].matchType = FWP_MATCH_EQUAL;
+    Condition[0].conditionValue.type = FWP_UINT16;
+    Condition[0].conditionValue.uint16 = 53;
+
+    Condition[1].fieldKey = FWPM_CONDITION_ALE_APP_ID;
+    Condition[1].matchType = FWP_MATCH_NOT_EQUAL;
+    Condition[1].conditionValue.type = FWP_BYTE_BLOB_TYPE;
+    Condition[1].conditionValue.byteBlob = openvpnblob;
+
+    /* Add filter condition to our interface. */
+    if (!win_wfp_add_filter(m_hEngineHandle, &Filter, NULL, &filterid))
+        goto err;
+    dmsg (D_LOW, "Filter (Block IPv4 DNS) added with ID=%I64d", filterid);
+
+    /* Second filter. Block IPv6 DNS queries except from OpenVPN itself. */
+    Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V6;
+
+    /* Add filter condition to our interface. */
+    if (!win_wfp_add_filter(m_hEngineHandle, &Filter, NULL, &filterid))
+        goto err;
+    dmsg (D_LOW, "Filter (Block IPv6 DNS) added with ID=%I64d", filterid);
+
+    /* Third filter. Permit IPv4 DNS queries from TAP. */
+    Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V4;
+    Filter.action.type = FWP_ACTION_PERMIT;
+
+    Condition[1].fieldKey = FWPM_CONDITION_IP_LOCAL_INTERFACE;
+    Condition[1].matchType = FWP_MATCH_EQUAL;
+    Condition[1].conditionValue.type = FWP_UINT64;
+    Condition[1].conditionValue.uint64 = &tapluid.Value;
+
+    /* Add filter condition to our interface. */
+    if (!win_wfp_add_filter(m_hEngineHandle, &Filter, NULL, &filterid))
+        goto err;
+    dmsg (D_LOW, "Filter (Permit IPv4 DNS queries from TAP) added with ID=%I64d", filterid);
+
+    /* Forth filter. Permit IPv6 DNS queries from TAP. */
+    Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V6;
+
+    /* Add filter condition to our interface. */
+    if (!win_wfp_add_filter(m_hEngineHandle, &Filter, NULL, &filterid))
+        goto err;
+    dmsg (D_LOW, "Filter (Permit IPv6 DNS queries from TAP) added with ID=%I64d", filterid);
+
+    FwpmFreeMemory0((void **)&openvpnblob);
+    return true;
+
+    err:
+        FwpmFreeMemory0((void **)&openvpnblob);
+        return false;
+}
+
+bool
+win_wfp_uninit()
+{
+    dmsg (D_LOW, "Uninitializing WFP");
+    if (m_hEngineHandle) {
+        FwpmEngineClose0(m_hEngineHandle);
+        m_hEngineHandle = NULL;
+    }
+    return true;
+}
+
+int
+win32_version_info()
+{
+    if (!IsWindowsXPOrGreater())
+    {
+        msg (M_FATAL, "Error: Windows version must be XP or greater.");
+    }
+
+    if (!IsWindowsVistaOrGreater())
+    {
+        return WIN_XP;
+    }
+
+    if (!IsWindows7OrGreater())
+    {
+        return WIN_VISTA;
+    }
+
+    if (!IsWindows8OrGreater())
+    {
+        return WIN_7;
+    }
+    else
+    {
+        return WIN_8;
+    }
+}
+
+const char *
+win32_version_string(struct gc_arena *gc, bool add_name)
+{
+    int version = win32_version_info();
+    struct buffer out = alloc_buf_gc (256, gc);
+
+    switch (version)
+    {
+        case WIN_XP:
+            buf_printf (&out, "5.1%s", add_name ? " (Windows XP)" : "");
+            break;
+        case WIN_VISTA:
+            buf_printf (&out, "6.0%s", add_name ? " (Windows Vista)" : "");
+            break;
+        case WIN_7:
+            buf_printf (&out, "6.1%s", add_name ? " (Windows 7)" : "");
+            break;
+        case WIN_8:
+            buf_printf (&out, "6.2%s", add_name ? " (Windows 8 or greater)" : "");
+            break;
+        default:
+            msg (M_NONFATAL, "Unknown Windows version: %d", version);
+            buf_printf (&out, "0.0%s", add_name ? " (unknown)" : "");
+            break;
+    }
+
+    return (const char *)out.data;
+}
+
 #endif