TITUS -- Totally Isolated TLS Unwrapping Server
===============================================

titus is a highly secure network proxy that terminates TLS (SSL)
connections and forwards the unencrypted traffic to some backend.
It is similar in purpose to stud and stunnel.

titus provides heightened security by running in extreme isolation.
The private key is stored in a dedicated process that doesn't talk to
the network, and all private key operations take place in this process.
Furthermore, every connection is handled by a new process that runs
as an unprivileged user in an unwritable and empty root directory.
These security features ensure that if there is a vulnerability in the
TLS processing code, it is very, very unlikely that an attacker could
steal your private key, access the memory of your application, sniff
data from other TLS connections, or otherwise attack your system.

titus aims to be as transparent as possible to the backend application.
Changes to the connection state between the client and titus are reflected
in the connection between titus and the backend, and vice-versa.  This
allows the backend to dictate throttling behavior, maximum connection
behavior, and so on.

On Linux, titus can operate in transparent proxy mode so that the client
IP address is preserved when contacting the backend.  This requires
special configuration with iptables and advanced routing (see TRANSPARENT
PROXY MODE in the titus(8) man page).

titus supports the Elliptic Curve Diffie-Hellman handshake, and also
provides advanced control over TLS settings, such as the Diffie-Hellman
modulus, and the curve used for Elliptic Curve Diffie-Hellman.  This is
handy if your backend's built-in TLS support is lacking.


CURRENT STATUS

The current version of titus is 0.3, released on 2015-11-28.  titus
aims to be bug-free and secure, though it is lacking in features and
needs additional performance optimization.  Additionally, we may make
backwards-incompatible changes to the behavior before titus reaches
version 1.0


NON-LINUX WARNING

On non-Linux systems, due to the lack of the prctl() syscall, titus cannot
prevent tracing/debugging of one titus process by another titus process.
This substantially reduces the isolation between TLS connections, although
private key operations remain isolated since they run as a separate user.

On FreeBSD 10.2-RELEASE and higher, titus uses procctl with PROC_TRACE_CTL
to disable tracing, which should provide isolation.  However, this has
not undergone security analysis yet and should be considered experimental.

A future version of titus will provide full isolation even on non-Linux
systems.


INSTALLING TITUS

If you use Debian or Ubuntu, see https://www.opsmate.com/titus/#getting
for information about installing the titus .deb package.  Using the .deb
package is highly recommended since it comes with a handy init script.

To build from source, see the BUILDING file.


CONFIGURING TITUS

Start with titus.conf.example and modify it to fit your needs.  Also see
the titus(8) man page.

If you're using the Debian package, start with the example config
in /usr/share/doc/titus/examples and place it in /etc/titus.
See /etc/titus/README for details.


RUNNING TITUS

Run `titus --config /path/to/titus.conf`.

If you're using the Debian package, use the init script to start/stop
titus like any other service.


PROJECT RESOURCES

Home page:	https://www.opsmate.com/titus
Git repository:	https://agwa.name/git/titus.git
		https://github.com/AGWA/titus.git (mirror)
GitHub project:	https://github.com/AGWA/titus
Issue tracker:	https://github.com/AGWA/titus/issues
Announce list:	https://lists.cloudmutt.com/mailman/listinfo/titus-announce
Discuss list:	https://lists.cloudmutt.com/mailman/listinfo/titus-discuss

For help or questions, send mail to the discuss list
<titus-discuss@lists.cloudmutt.com>.  To report a bug or make a
feature request, please open an issue at GitHub or send mail to the
discuss list.  To contribute code, please send a properly-formatted
patch to the discuss list, or open a pull request at GitHub.


AUTHOR

titus was written by Andrew Ayer <agwa@andrewayer.name>.


FURTHER DOCUMENTATION

 * For copyright/license, see COPYING.
 * For build instructions, see BUILDING.
 * For general documentation, see the titus(8) man page.