wintun: stop sending TAP-Windows6 ioctls to NDIS device

Wintun doesn't have its own I/O device. Rather, it taps on existing
Windows-provided NDIS device. Sending TAP-Windows6 IOCTL requests to it
is risky, as TAP-Windows6 is using one of the well-known device types
(FILE_DEVICE_UNKNOWN) with function IDs as 1, 2, 3 etc. raising a chance
of collision as NDIS might react to one of these IOCTLs.

Signed-off-by: Simon Rozman <simon@rozman.si>
Acked-by: Lev Stipakov <lstipakov@gmail.com>
Message-Id: <20200108115224.38-1-simon@rozman.si>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg19309.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/src/openvpn/error.c b/src/openvpn/error.c
index b2492f2be5fafbe04c4295aea50c900f10ab22da..ad4f0ef44f7256609b671eb55fa50a28ca2ffae9 100644 (file)
--- a/src/openvpn/error.c
+++ b/src/openvpn/error.c
@@ -688,7 +688,10 @@ x_check_status(int status,
         }
 #elif defined(_WIN32)
         /* get possible driver error from TAP-Windows driver */
-        extended_msg = tap_win_getinfo(tt, &gc);
+        if (tuntap_defined(tt))
+        {
+            extended_msg = tap_win_getinfo(tt, &gc);
+        }
 #endif
         if (!ignore_sys_error(my_errno))
         {

diff --git a/src/openvpn/sig.c b/src/openvpn/sig.c
index d7f2abb81cc1a922e79d3e51951484412d68363a..6e3379fe01fd40eea77bfde2484f4375c619c5dc 100644 (file)
--- a/src/openvpn/sig.c
+++ b/src/openvpn/sig.c
@@ -317,8 +317,11 @@ print_status(const struct context *c, struct status_output *so)
 #ifdef _WIN32
     if (tuntap_defined(c->c1.tuntap))
     {
-        status_printf(so, "TAP-WIN32 driver status,\"%s\"",
-                      tap_win_getinfo(c->c1.tuntap, &gc));
+        const char *extended_msg = tap_win_getinfo(c->c1.tuntap, &gc);
+        if (extended_msg)
+        {
+            status_printf(so, "TAP-WIN32 driver status,\"%s\"", extended_msg);
+        }
     }
 #endif
 

diff --git a/src/openvpn/tun.c b/src/openvpn/tun.c
index 8e0d3df8c2bacfeed918d6ab0987894f1c0caa87..32a3f756a7788577cb592b2c97d37d8d3f938632 100644 (file)
--- a/src/openvpn/tun.c
+++ b/src/openvpn/tun.c
@@ -6411,7 +6411,7 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun
 const char *
 tap_win_getinfo(const struct tuntap *tt, struct gc_arena *gc)
 {
-    if (tt && tt->hand != NULL)
+    if (!tt->wintun)
     {
         struct buffer out = alloc_buf_gc(256, gc);
         DWORD len;
@@ -6429,7 +6429,7 @@ tap_win_getinfo(const struct tuntap *tt, struct gc_arena *gc)
 void
 tun_show_debug(struct tuntap *tt)
 {
-    if (tt && tt->hand != NULL)
+    if (!tt->wintun)
     {
         struct buffer out = alloc_buf(1024);
         DWORD len;