* Use C++11 range-based iterators.
* Use std::string rather than std::ostringstream
for string formatting.
* Added to_string() method.
* Added local_addr() method.
Signed-off-by: James Yonan <james@openvpn.net>
Created a lightweight abstraction layer so that another i/o
reactor can be dropped in place of asio.
The basic approach is to rename all references to asio::xxx
types to openvpn_io::xxx and then make openvpn_io a
preprocessor variable that points to the top-level namespace
of the i/o reactor implementation.
All of the source files that currently include <asio.hpp> now
include <openvpn/io/io.hpp> instead:
This gives us a lightweight abstraction layer that allows us
to define openvpn_io to be something other than asio.
Other changes:
* Inclusion of asio by scripts/build is now optional, and is
enabled by passing ASIO=1 or ASIO_DIR=<dir>.
* Refactored openvpn/common/socktypes.hpp to no longer
require asio.
* Refactored openvpn/log/logthread.hpp to no longer require
asio.
* Added openvpn::get_hostname() method as alternative to
calling asio directly.
* openvpn/openssl/util/init.hpp will now #error
if USE_ASIO is undefined.
Signed-off-by: James Yonan <james@openvpn.net>
to HTTP CONNECT but implemented over the OpenVPN protocol.
1. Client connects to relay server as if it were connecting
to an ordinary OpenVPN server.
2. Client authenticates to relay server using its client
certificate.
3. Client sends a PUSH_REQUEST method to relay server which
then replies with a RELAY message instead of PUSH_REPLY.
4. On receiving the RELAY message, the client attempts to
reconnect using the existing transport socket. The
server will proxy this new connection (at the transport
layer) to a second server (chosen by the relay server)
that is the target of proxy.
5. The client must establish and authenticate a new session
from scratch with the target server, only reusing the
transport layer socket from the original connection to
the relay server.
6. The relay acts as a man-in-the-middle only at the
transport layer (like most proxies), i.e. it forwards
the encrypted session between client and target server
without decrypting or having the capability to decrypt
the session.
7. The client is designed to protect against potentially
untrusted or malicious relays:
(a) The client never transmits the target server
username/password credentials to the relay server.
(b) The relay forwards the encrypted OpenVPN session
between client and target server without having
access to the session keys.
(c) The client configuration has a special directive
for relay server CA (<relay-extra-ca>) and relay
server tls-auth key (<relay-tls-auth>) to allow
for separation of TLS/crypto configuration between
relay and target servers.
(d) The client will reject any PUSH_REPLY messages
from the relay itself to prevent the relay from
trying to establish a tunnel directly with the
client.
Example configuring a client for relay:
# remote addresses point to the relay server
remote ... 1194 udp
remote ... 443 tcp
# include all other directives for connecting
# to the target server
# enable relay mode
relay-mode
# constrain the relay server's cert type
relay-ns-cert-type server
# include extra CAs that validate the relay
# server cert (optional).
<relay-extra-ca>
-----BEGIN CERTIFICATE-----
. . .
-----END CERTIFICATE-----
</relay-extra-ca>
# specify the TLS auth key for the relay server
relay-key-direction 1
<relay-tls-auth>
-----BEGIN OpenVPN Static key V1-----
. . .
-----END OpenVPN Static key V1-----
</relay-tls-auth>
Triple DES, and other 64-bit block-size ciphers vulnerable
to "Sweet32" birthday attack (CVE-2016-6329). Limit such
cipher keys to no more than 64 MB of data
encrypted/decrypted. While our overall goal is to limit
data-limited keys to 64 MB, we trigger a renegotiation
at 48 MB to compensate for possible delays in renegotiation
and rollover to the new key.
This client-side implementation extends data limit
protection to the entire session, even when the server
doesn't implement data limits.
This capability is advertised to servers via the a
peer info setting:
IV_BS64DL=1
meaning "Block-Size 64-bit Data Limit". The "1" indicates
the implementation version.
The implementation currently has some limitations:
* Keys are renegotiated at a maximum rate of once per
5 seconds to reduce the likelihood of loss of
synchronization between peers.
* The maximum renegotiation rate may be further extended
if the peer delays rollover from the old to new key
after renegotiation.
Added N_KEY_LIMIT_RENEG stats counter to count the number
of data-limit-triggered renegotiations.
Added new stats counter KEY_STATE_ERROR which roughly
corresponds to the OpenVPN 2.x error "TLS Error:
local/remote TLS keys are out of sync".
Prevously, the TLS ack/retransmit timeout was hardcoded to
2 seconds. Now we lower the default to 1 second and make
it variable using the (pushable) "tls-timeout" directive.
Additionally, the tls-timeout directive can be specified
in milliseconds instead of seconds by using the
"tls-timeout-ms" form of the directive.
Made the "become primary" time duration configurable via
the (pushable) "become-primary" directive which accepts
a number-of-seconds parameter. become-primary indicates
the time delay between renegotiation and rollover to the
new key for encryption/transmission. become-primary
defaults to the handshake-window which in turn defaults
to 60 seconds.
Incremented core version to 3.0.20.
INFO,<payload>
Payload can be any UTF-8 printable string under 64 KB
(multiple lines are okay).
INFO notifications can be sent from server to client
in real-time, on any active client connection.
The client will attach the payload to an INFO event and
forward it to the controlling app via the event callback:
virtual void event(const Event&) = 0;
receive path to reassemble messages fragmented by the
SSL layer up to a max message size of 64 KB.
Ramifications:
* Peer info data and pushed options can be significantly
larger (i.e. approaching 64 KB).
* Less need for the options continuation feature.
Limitations:
* While this patch doesn't change the underlying OpenVPN
protocol, it can result in messages being sent that are
fragmented by the receiving SSL implementation into
multiple buffers. Implementations that lack reassembly
capabilities (such as OpenVPN 2.x at this point in time)
would see each buffer fragment as a separate message.
* This patch running on the server will break negotiation
with pre-peer-info clients. Basically this means it will
interoperate with any OpenVPN 3 version or OpenVPN 2.x
version that includes the June 2010 commit "Implemented a
key/value auth channel from client to server.
Version 2.1.1i".
* eliminated the GENERAL_POOL enumeration and vector.
* added support for standalone "ifconfig-push" directive
as alternative to "server" for OMI agents that
manage their own IP address pools.
In ServerProto::Session (servproto.hpp),
push_halt_restart_msg() can now push AUTH_FAILED messages
as well.
In fact ServerProto::Session::auth_failed() is now defined
in terms of push_halt_restart_msg().
When parsing listen directives, "ssl" or "!ssl" may
be specified as the last parameter to set the ssl
switch. By default, the switch is set to unspecified.
to be multiplied by the number of processor cores on the machine
using this syntax:
listen 0.0.0.0 1194 udp 4*N
The 4*N syntax indicates that OpenVPN should spawn 4 * N threads
to listen on 0.0.0.0:1194 where N is the number of processor
cores on the machine.
new AuthCert object, and pass it through to
management decision object along with other creds
to consider for authentication.
In OpenSSL driver, split the verify_callback
function into client/server versions.
Modified InitProcess to do a special one-time call of
SSL_get_ex_new_index in OpenSSL library, so that we
can store a private object pointer in an OpenSSL
SSL struct.
TODO: Add AuthCert functionality to PolarSSL driver.
1. force_aes_cbc_ciphersuites flag will disable V2.
2. Added class CryptoDCSettings to Manage cipher/digest settings,
DC factory, and DC context. A CryptoDCSettings instance is
now declared as a member of ProtoContext::Config and is used
to define the cipher/digest pair of the config.
3. ProtoContext::Config::load now parses the "tun-mtu" directive.
Server-side changes:
1. Parse "keepalive" directive, using the same logic
as OpenVPN 2.x.
2. Added ProtoContext::init_data_channel() method for initializing
the data channel after IV_x peer info received from client.
* Use standard naming convention in openvpn/addr template classes,
where "ADDR" is the address class, the class template name
ends with "Type", and the IP::Addr specialization of the class
template has the "Type" suffix removed.
* Added class RangePartitionType and RangeType::pull_front to help
with subnet subdivision.
* Misc convenience methods added to RangeType and RouteType.
New file openvpn/server/vpnservnetblock.hpp :
* Added class VPNServerNetblock for deriving useful info about the
top-level VPN IP address block and helping to subdivide it
across server threads.
* Make class Route standalone, moving it out of namespace
CIDRMap.
CryptoAlgs:
* Added comments
* For type-safety, mode() now returns a Mode rather than an
int.
CryptoDC:
* Added CRYPTO_DEFINED flag to indicate when encrypt() and
decrypt() methods are implemented by a data channel
provider.
Manage:
* Implemented skeleton management API for server-side client
authentication and managing client-instance properties.
Proto:
* Added Config::update_dc_factory() method.
* Support new CryptoDCInstance::CRYPTO_DEFINED flag.
* Updated server_auth() method to support SafeString transit
of client-provided auth-user-pass password to management
layer.
* control_send now does a reset() on the provided
Ptr reference before returning to reflect the
transfer-of-ownership of the underlying buffer.
* Implemented disable_keepalive() and override_dc_factory
methods.
Transbase (server) new methods:
// disable keepalive for rest of session
virtual void disable_keepalive() = 0;
// override the data channel factory
virtual void override_dc_factory(const CryptoDCFactory::Ptr& dc_factory) = 0;
// override the tun provider
virtual TunClientInstanceRecv* override_tun(TunClientInstanceSend* tun) = 0;
ServProto:
* Added abstract base classes for Tun factories and client instance
sender/receivers.
* Added Tun and Management linkages.
* Added new receiver methods for overriding the data channel
factory, Tun factory, and keepalive config.
* Added AuthCreds support.
to use Link abstraction (openvpn/common/link.hpp) to link with
transport layer (and other layers such as routing and management
as development progresses).
