From: Simon Rozman <simon@rozman.si>
Date: Fri, 20 Dec 2019 19:38:05 +0000 (+0100)
Subject: wintun: register ring buffers when iterating adapters
X-Git-Tag: v2.5_beta1~223
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c1a555585c90aa26390ef2f50cadd479b47541f2;p=thirdparty%2Fopenvpn.git

wintun: register ring buffers when iterating adapters

Wintun adapters may be considered available if ring buffer registration
succeeded. Therefore, we must attempt to register ring buffers when
iterating adapters and continue on failure.

Signed-off-by: Simon Rozman <simon@rozman.si>
Acked-by: Lev Stipakov <lstipakov@gmail.com>
Message-Id: <20191220193805.34-1-simon@rozman.si>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg19288.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
---

diff --git a/src/openvpn/tun.c b/src/openvpn/tun.c
index c6bbbd417..aef2c7f81 100644
--- a/src/openvpn/tun.c
+++ b/src/openvpn/tun.c
@@ -6129,11 +6129,72 @@ tuntap_dhcp_mask(const struct tuntap *tt, const char *device_guid)
     gc_free(&gc);
 }
 
+static bool
+tun_try_open_device(struct tuntap *tt, const char *device_guid, const struct device_instance_id_interface *device_instance_id_interface)
+{
+    const char *path = NULL;
+    char tuntap_device_path[256];
+
+    if (tt->wintun)
+    {
+        const struct device_instance_id_interface *dev_if;
+
+        /* Open Wintun adapter */
+        for (dev_if = device_instance_id_interface; dev_if != NULL; dev_if = dev_if->next)
+        {
+            if (strcmp(dev_if->net_cfg_instance_id, device_guid) == 0)
+            {
+                path = dev_if->device_interface_list;
+                break;
+            }
+        }
+        if (path == NULL)
+        {
+            return false;
+        }
+    }
+    else
+    {
+        /* Open TAP-Windows adapter */
+        openvpn_snprintf(tuntap_device_path, sizeof(tuntap_device_path), "%s%s%s",
+                            USERMODEDEVICEDIR,
+                            device_guid,
+                            TAP_WIN_SUFFIX);
+        path = tuntap_device_path;
+    }
+
+    tt->hand = CreateFile(path,
+                   GENERIC_READ | GENERIC_WRITE,
+                   0,                /* was: FILE_SHARE_READ */
+                   0,
+                   OPEN_EXISTING,
+                   FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED,
+                   0);
+    if (tt->hand == INVALID_HANDLE_VALUE)
+    {
+        msg(D_TUNTAP_INFO, "CreateFile failed on %s device: %s", tt->wintun ? "Wintun" : "TAP-Windows", path);
+        return false;
+    }
+
+    if (tt->wintun)
+    {
+        /* Wintun adapter may be considered "open" after ring buffers are successfuly registered. */
+        if (!wintun_register_ring_buffer(tt))
+        {
+            msg(D_TUNTAP_INFO, "Failed to register %s adapter ring buffers", device_guid);
+            CloseHandle(tt->hand);
+            tt->hand = NULL;
+            return false;
+        }
+    }
+
+    return true;
+}
+
 static void
 tun_open_device(struct tuntap *tt, const char *dev_node, const char **device_guid)
 {
     struct gc_arena gc = gc_new();
-    char *path = NULL;
     char tuntap_device_path[256];
     const struct tap_reg* tap_reg = get_tap_reg(&gc);
     const struct panel_reg* panel_reg = get_panel_reg(&gc);
@@ -6197,27 +6258,11 @@ tun_open_device(struct tuntap *tt, const char *dev_node, const char **device_gui
 
             if (tt->wintun)
             {
-                const struct device_instance_id_interface* dev_if;
-
                 if (!is_picked_device_wintun)
                 {
                     /* wintun driver specified but picked adapter is not wintun, proceed to next one */
                     goto next;
                 }
-
-                path = NULL;
-                for (dev_if = device_instance_id_interface; dev_if != NULL; dev_if = dev_if->next)
-                {
-                    if (strcmp(dev_if->net_cfg_instance_id, *device_guid) == 0)
-                    {
-                        path = (char*)dev_if->device_interface_list;
-                        break;
-                    }
-                }
-                if (path == NULL)
-                {
-                    goto next;
-                }
             }
             else
             {
@@ -6226,28 +6271,9 @@ tun_open_device(struct tuntap *tt, const char *dev_node, const char **device_gui
                     /* tap-windows6 driver specified but picked adapter is wintun, proceed to next one */
                     goto next;
                 }
-
-                /* Open Windows TAP-Windows adapter */
-                openvpn_snprintf(tuntap_device_path, sizeof(tuntap_device_path), "%s%s%s",
-                                 USERMODEDEVICEDIR,
-                                 *device_guid,
-                                 TAP_WIN_SUFFIX);
-                path = tuntap_device_path;
             }
 
-            tt->hand = CreateFile(path,
-                                  GENERIC_READ | GENERIC_WRITE,
-                                  0,                /* was: FILE_SHARE_READ */
-                                  0,
-                                  OPEN_EXISTING,
-                                  FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED,
-                                  0);
-
-            if (tt->hand == INVALID_HANDLE_VALUE)
-            {
-                msg(D_TUNTAP_INFO, "CreateFile failed on %s device: %s", tt->wintun ? "wintun" : "TAP", tuntap_device_path);
-            }
-            else
+            if (tun_try_open_device(tt, *device_guid, device_instance_id_interface))
             {
                 break;
             }
@@ -6261,7 +6287,7 @@ tun_open_device(struct tuntap *tt, const char *dev_node, const char **device_gui
      * GUID using the registry */
     tt->actual_name = string_alloc(actual_buffer, NULL);
 
-    msg(M_INFO, "%s device [%s] opened: %s", tt->wintun ? "Wintun" : "TAP-WIN32", tt->actual_name, path);
+    msg(M_INFO, "%s device [%s] opened", tt->wintun ? "Wintun" : "TAP-WIN32", tt->actual_name);
     tt->adapter_index = get_adapter_index(*device_guid);
 
     gc_free(&gc);
@@ -6372,14 +6398,7 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun
 
     tun_open_device(tt, dev_node, &device_guid);
 
-    if (tt->wintun)
-    {
-        if (!wintun_register_ring_buffer(tt))
-        {
-            msg(M_FATAL, "Failed to register ring buffers");
-        }
-    }
-    else
+    if (!tt->wintun)
     {
         tuntap_post_open(tt, device_guid);
     }