NAME

       tlsdate - secure parasitic rdate replacement

SYNOPSIS

       tlsdate  [-hnvVstl]  [-H  [hostname]]  [-p  [port]]  [-P  [sslv23|sslv3|tlsv1]] [--certdir
       [dirname]] [-x [--proxy] proxy-type://proxyhost:proxyport]

DESCRIPTION

       tlsdate is a tool for setting the system clock  by  hand  or  by  communication  with  the
       network.  It  does not set the Real Time Clock. It is designed to be as secure as TLS (RFC
       2246) but of course the security of TLS is  often  reduced  to  whichever  CA  racket  you
       believe  is  trustworthy.  By default, tlsdate trusts your local CA root store - so any of
       these companies could assist in a MITM attack against you and you'd be screwed.

       This tool is designed to be run by hand or as a system daemon. It must be run as  root  or
       otherwise have the proper caps; it will not be able to set the system time without running
       as root or another privileged user.

OPTIONS

       -h | --help
              Print the help message

       -s | --skip-verification
              Skip certificate verification

       -H | --host [hostname|ip]
              Set remote hostname (default: 'www.ptb.de')

       -n | --dont-set-clock
              Do not set the system clock to the time of the remote server

       -p | --port [port]
              Set remote port (default: '443')

       -P | --protocol [sslv23|sslv3|tlsv1]
              Set protocol to use when communicating with server (default: 'tlsv1')

       -C | --certdir [dirname]
              Set the local directory where certificates are located (default:  '/etc/ssl/certs')
              This  allows  for certificate or certificate authority (CA) pinning. To ensure that
              signatures are only valid if they are signed by a specific CA or  certificate,  set
              the path to a directory containing only the desired certificates.

       -x | --proxy [proxy-type://proxyhost:proxyport]
              The proxy argument expects HTTP, SOCKS4A or SOCKS5 formatted as followed:

               http://127.0.0.1:8118
               socks4a://127.0.0.1:9050
               socks5://127.0.0.1:9050

              The proxy support should not leak DNS requests and is suitable for use with Tor.

       -v | --verbose
              Provide verbose output

       -V | --showtime
              Show the time retrieved from the remote server

       -t | --timewarp
              If  the  local  clock  is  before  RECENT_COMPILE_DATE;  we  set  the  clock to the
              RECENT_COMPILE_DATE. If the local clock is after RECENT_COMPILE_DATE, we leave  the
              clock  alone.  Clock  setting  is  performed as the first operation and will impact
              certificate verification. Specifically, this option is helpful if  on  first  boot,
              the  local  system  clock  is  set back to the era of Disco and Terrible Hair. This
              should ensure that X509_V_ERR_CERT_NOT_YET_VALID or X509_V_ERR_CERT_HAS_EXPIRED are
              not  encountered because of a broken RTC or the lack of a local RTC; we assume that
              tlsdate is recompiled yearly and that all  certificates  are  otherwise  considered
              valid.

       -l | --leap
              Normally, the passing of time or time yet to come ensures that SSL verify functions
              will fail to validate  certificates.  Commonly,  X509_V_ERR_CERT_NOT_YET_VALID  and
              X509_V_ERR_CERT_HAS_EXPIRED  are  painfully annoying but still very important error
              states. When the only issue  with  the  certificates  in  question  is  the  timing
              information,  this  option allows you to trust the remote system's time, as long as
              it is after RECENT_COMPILE_DATE and before MAX_REASONABLE_TIME. The connection will
              only       be       trusted       if      X509_V_ERR_CERT_NOT_YET_VALID      and/or
              X509_V_OKX509_V_ERR_CERT_HAS_EXPIRED are  the  only  errors  encountered.  The  SSL
              verify  function  will  not return X509_V_OK if there are any other issues, such as
              self-signed certificates or if the user pins to a CA that is not used by the remote
              server.  This  is  useful  if  your RTC is broken on boot and you are unable to use
              DNSEC until you've at least had some kind  of  leap  of  cryptographically  assured
              data.

BUGS

       It's likely! Let us know by contacting jacob@appelbaum.net

       Note that tlsdate(1) is still in Alpha, and may not work as expected.

AUTHOR

       Jacob Appelbaum <jacob at appelbaum dot net>

SEE ALSO

       tlsdated(1), tlsdate-helper(1) tlsdate-routeup(1) tlsdate-dbus-announce(1)