2010.08.09 -- Version 2.1.2
* Windows security issue:
Fixed potential local privilege escalation vulnerability in
Windows service. The Windows service did not properly quote the
executable filename passed to CreateService. A local attacker
with write access to the root directory C:\ could create an
executable that would be run with the same privilege level as
the OpenVPN Windows service. However, since non-Administrative
users normally lack write permission on C:\, this vulnerability
is generally not exploitable except on older versions of Windows
(such as Win2K) where the default permissions on C:\ would allow
any user to create files there.
Credit: Scott Laurie, MWR InfoSecurity
* Added Python-based based alternative build system for Windows using
Visual Studio 2008 (in win directory).
* When aborting in a non-graceful way, try to execute do_close_tun in
init.c prior to daemon exit to ensure that the tun/tap interface is
closed and any added routes are deleted.
* Fixed an issue where AUTH_FAILED was not being properly delivered
to the client when a bad password is given for mid-session reauth,
causing the connection to fail without an error indication.
* Don't advance to the next connection profile on AUTH_FAILED errors.
* Fixed an issue in the Management Interface that could cause
a process hang with 100% CPU utilization in --management-client
mode if the management interface client disconnected at the
point where credentials are queried.
* Fixed an issue where if reneg-sec was set to 0 on the client,
so that the server-side value would take precedence,
the auth_deferred_expire_window function would incorrectly
return a window period of 0 seconds. In this case, the
correct window period should be the handshake window
* Modified ">PASSWORD:Verification Failed" management interface
notification to include a client reason string:
>PASSWORD:Verification Failed: 'AUTH_TYPE' ['REASON_STRING']
* Enable exponential backoff in reliability layer
* Set socket buffers (SO_SNDBUF and SO_RCVBUF) immediately after
socket is created rather than waiting until after connect/listen.
* Management interface performance optimizations:
1. Added env-filter MI command to perform filtering on env vars
passed through as a part of --management-client-auth
2. man_write will now try to aggregate output into larger blocks
(up to 1024 bytes) for more efficient i/o
* Fixed minor issue in Windows TAP driver DEBUG builds
where non-null-terminated unicode strings were being
* Fixed issue on Windows with MSVC compiler, where TCP_NODELAY support
was not being compiled in.
* Proxy improvements:
Improved the ability of http-auth "auto" flag to dynamically detect
the auth method required by the proxy.
Added http-auth "auto-nct" flag to reject weak proxy auth methods.
Added HTTP proxy digest authentication method.
Removed extraneous openvpn_sleep calls from proxy.c.
* Implemented http-proxy-override and http-proxy-fallback directives to
easier for OpenVPN client UIs to start a pre-existing client config
proxy options, or to adaptively fall back to a proxy connection if a
* Implemented a key/value auth channel from client to server.
* Fixed issue where bad creds provided by the management interface
for HTTP Proxy Basic Authentication would go into an infinite
retry-fail loop instead of requerying the management interface for
* Added support for MSVC debugging of openvpn.exe in settings.in:
# Build debugging version of openvpn.exe
* Implemented multi-address DNS expansion on the network field of route
When only a single IP address is desired from a multi-address DNS
expansion, use the first address rather than a random selection.
* Added --register-dns option for Windows.
Fixed some issues on Windows with --log, subprocess creation
for command execution, and stdout/stderr redirection.
* Fixed an issue where application payload transmissions on the
TLS control channel (such as AUTH_FAILED) that occur during
or immediately after a TLS renegotiation might be dropped.
* Added warning about tls-remote option in man page.