stone(1)

NAME
stone - Simple Repeater

SYNOPSIS
stone [-C file] [-P command] [-Q options] [-N] [-d] [-p] [-n]
[-u max] [-f n] [-l] [-L file] [-a file] [-i file]
[-X n] [-T n] [-A <n>] [-r]
[-x port[,port][-port]... xhost... --]
[-s send expect... --]
[-b [var=val]... n master:port backup:port]
[-B host:port host1:port1... --]
[-I host]
[-o n] [-g n] [-t dir] [-D] [-c dir]
[-q SSL] [-z SSL]
[-M install name] [-M remove name]
st [-- st]...

DESCRIPTION
Stone is a TCP & UDP repeater in the application layer. It repeats TCP and UDP from inside to outside of a firewall, or from outside to inside.

Stone has following features:

1. Stone supports Win32.
    Formerly, UNIX machines are used as firewalls, but recently WindowsNT machines are used, too. You can easily run stone on WindowsNT and Windows95. Of course, available on Linux, FreeBSD, BSD/OS, SunOS, Solaris, HP-UX and so on.

2. Simple.
    Stone's source code is only 10000 lines long (written in C language), so you can minimize the risk of security holes.

3. Stone supports SSL.
    Using OpenSSL (http://www.openssl.org/), stone can encrypt/decrypt. Client verifications, and server verifications are also supported. Stone can send a substring of the subject of the certificate to the destination.

4. Stone is a http proxy.
    Stone can also be a tiny http proxy.

5. POP -> APOP conversion.
    With stone and a mailer that does not support APOP, you can access to an APOP server.

6. Stone supports IPv6.
    Stone can convert IP and IPv6 each other. With stone, you can use IP-only software on IPv6 network.

OPTIONS
If the -C file flag is used, the program read these options and sts from the configuration file file. If the -P command flag is used, the program executes specified pre-processor to read the configuration file. -Q options can be used to pass options to the pre-processor. If the -N flag is used, stone will terminate after parsing options and configuration file without opening the ports.

If the -d flag is used, then increase the debug level. If the -p flag is used, data repeated by stone are dumped. If the -n is used, IP addresses and service port numbers are shown instead of host names and service names.

If the -u max flag (max is integer) is used, the program memorize max UDP sources simultaneously. The default value is 100. If the -f n flag (n is integer) is used, the program spawn n child processes. The default behavior is not to spawn any child processes.

If the -l flag is used, the program sends error messages to the syslog instead of stderr. If the -L file (file is a file name) flag is used, the program writes error messages to the file. If the -a file flag is used, the program writes accounting to the file. If the -i file flag is used, the program writes its process ID to the file.

The -X n flag alters the buffer size of the repeater. The default value is 1000 bytes. If the -T n is used, the timeout of TCP sessions can be specified to n sec. Default: 600 (10 min). The -A flag specifies the maximum length the queue of pending connections may grow to. Default: 50. The -r flag is used, SO_REUSEADDR is set on the socket of st.

Using the -x port[,port][-port]... xhost... -- flag, the http proxy (described later) can only connect to xhost:port. If more than one -x ... -- flags are designated, the posterior one whose port list matches the connecting port. If the -x -- is used, prior -x flags are ignored.

The -b n master:port backup:port flag designates the backup destination for master:port. The program checks every n seconds whether master:port is connectable, using the health check script defined by -s flag described below. If not, the backup is used instead. Alternative host can be checked, using host=host and alternative port, using port=port.

The -s send expect... -- flag defines the health check script. Sending send, then checks whether the response match the regular expression expect.

The -B host:port host1:port1... -- is for the destination group. If the destination of st is host:port, the program chooses a destination randomly from the group. The destination host:port that is designated by -b flag and turned out unhealthy, is excluded from the group.

The -I host designates the interface used as the source address of the connection to the desctination.

If the -o n or -g n flag is used, the program set its uid or gid to n respectively. If the -t dir flag (dir is a directory) is used, the program change its root to the directory. If the -D flag is used, stone runs as a daemon. The -c dir flag designates the directory for core dump.

The -M install name and the -M remove name flags are for NT service. name is the service name. Start the service using the command: net start name. To install stone service as the name repeater, for example:

    C:\>stone -M install repeater -C C:\stone.cfg
    C:\>net start repeater

The -q SSL and the -z SSL flags are for SSL encryption. The -q SSL is for the client mode, that is, when stone connects to the other SSL server as a SSL client. The -z SSL if for the server mode, that is, when other SSL clients connect to the stone.

SSL is one of the following.

default
    reset SSL options to the default. Using multiple st, different SSL options can be designated for each st.
verbose
    verbose mode.
verify
    require SSL certificate to the peer.
verify,once
    request a client certificate on the initial TLS/SSL handshake. (-z only)
verify,ifany
    The certificate returned (if any) is checked. (-z only)
verify,none
    never request SSL certificate to the peer.
crl_check
    lookup CRLs.
crl_check_all
    lookup CRLs for whole chain.
uniq
    if the serial number of peer's SSL certificate is different from the previous session, deny it.
ren=regex
    The certificate of the peer must satisfy the regex. n is the depth. re0 means the subject of the certificate, and re1 means the issure. The maximum of n is 9. if n is negative, re-1 means the root CA and re-2 means its child CA.
depth=n
    The maximum of the certificate chain. If the peer's certificate exceeds n, the verification fails. The maximum of n is 9.
tls1
    Just use TLSv1 protocol.
ssl3
    Just use SSLv3 protocol.
ssl2
    Just use SSLv2 protocol.
no_tls1
    Turn off TLSv1 protocol.
no_ssl3
    Turn off SSLv3 protocol.
no_ssl2
    Turn off SSLv2 protocol.
sni Server Name Indication (SNI).
servername=str
    The name of the server indicated by SNI.
bugs
    Switch on all SSL implementation bug workarounds.
serverpref
    Use server's cipher preferences (only SSLv2).
sid_ctx=str
    Set session ID context.
passfile=file
    The filename of the file containing password of the key.
passfilepat=file
    The pattern of the filename.
key=file
    The filename of the secret key of the certificate.
keypat=file
    The pattern of the filename.
cert=file
    The filename of the certificate.
certpat=file
    The pattern of the filename.
certkey=file
    The filename of the certificate with the secret key.
certkeypat=file
    The pattern of the filename.
CAfile=file
    The filename of the certificate of the CA.
CApath=dir
    The directory of the certificate files.
pfx=file
    The filename of the PKCS#12 bag.
pfxpat=file
    The pattern of the filename.
store=prop
    [Windows] Use the secret key in the Cert Store. designate by "SUBJ:<substr>" or "THUMB:<hex>".
storeCA
    [Windows] Use CA certificates in the Cert Store.
cipher=list
    The list of ciphers.
lbn=m
    change the destination according to the certificate of the peer. The number calculated from the matched string to the nth ( ... ) in the ``regex'' of SSL options (mod m) is used to select the destination from the destination group defined by -B flag.

st is one of the following. Multiple st can be designated, separated by --.

(1) host:port sport [xhost...]
(2) host:port shost:sport [xhost...]
(3) proxy sport [xhost...]
(4) host:port/http sport request [xhost...]
(5) host:port/proxy sport header [xhost...]
(6) health sport [xhost...]

The program repeats the connection on port sport to the other machine host port port. If the machine, on which the program runs, has two or more interfaces, type (2) can be used to repeat the connection on the specified interface shost. You can also specify path name that begins with ``/'' or ``./'', instead of host:port so that the program handles a unix domain socket.

Type (3) is a http proxy. Specify the machine, on which the program runs, and port sport in the http proxy settings of your WWW browser. Extentions can be added to the ``proxy'' like xhost/ext. ext is:

v4only
    limit the destination within IP addresses.

v6only
    limit the destination within IPv6 addresses.

Type (4) relays stream over http request. request is the request specified in HTTP 1.0. In the request, is the escape character, and the following substitution occurs.

    \\n newline (0x0A)
    \\r return (0x0D)
    \\t tab (0x09)
    \\\\
        itself (0x5C)
    \\a the IP address of the client connecting to the stone.
    \\A IP address of the client:port number
    \\d the destination IP address
    \\D dst IP address:port number (for transparent proxy)
    \\u uid (number) of the client
    \\U user name of the client
    \\g gid (number) of the client
    \\G group name of the client
        \u \U \g \G are valid in the case of unix domain socket
    \\0 the serial number of peer's SSL certificate.
    \\1 - \\9
        the matched string in the ``regex'' of SSL options.
    \\?1then\\:else\\/
        if 1 (2 - 9 in a similar way) is not null, then, otherwise else.

Type (5) repeats http request with header in the top of request headers. The above escapes can be also used. If /mproxy is designated instead of /proxy, header is added to each request headers.

Type (6) designates the port that other programs can check whether the stone runs `healthy' or not. Following commands are available to check the stone.

    HELO any string
        returns the status of the stone
    STAT
        # of threads, mutex conflicts
    FREE
        length of free lists
    CLOCK
        seconds passed
    CVS_ID
        CVS ID
    CONFIG
        content of the configuration file
    STONE
        configuration of each stones
    LIMIT var n
        check the value of var is less than n

var is one of the following:

    PAIR
        the number of ``pair''
    CONN
        the number of ``conn''
    ESTABLISHED
        seconds passed since the last conn established
    READWRITE
        seconds passed since the last read/write
    ASYNC
        the number of threads

The response of the stone is 2xx when normal, or 5xx when abnormal on the top of line.

If the xhost are used, only machines or its IP addresses listed in xhost separated by space character can connect to the program and to be repeated.

Extentions can be added to the xhost like xhost/ex,ex.... ex is:

m   You can designate the length of prefix bits of the netmask, so that only machines on specified. In the case of class C network 192.168.1.0, for example, use ``192.168.1.0/24''.

v4  xhost is resolved as the IP address.

v6  xhost is resolved as the IPv6 address.

pm  the data repeated by the program are dumped, only if it was connected by the machines specified by xhost. m is the dump mode, equivalent to the number of -p options.

Use ``!'' instead of ``xhost'', to deny machines by following xhost.

Extentions can be added to the port like port/ext,ext.... ext is:

udp repeats UDP instead of TCP.

ssl forwards with encryption.

v6  connects to the destination using IPv6.

base
    forwards with MIME base64 encoding.

Extentions can be added to the sport like sport/ext,ext.... ext is:

udp repeats UDP instead of TCP.

apop
    converts POP to APOP. The conversion is derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm.

ssl forwards with decryption.

v6  accepts connection using IPv6. If shost is omitted like (1), IP is also acceptable.

v6only
    accepts connection using IPv6 only. Even if shost is omitted like (1), IP is not acceptable.

base
    forwards with MIME base64 decoding.

http
    relays stream over http.

ident
    identifies the owner of the incoming connection on the peer using ident protocol (RFC1413).

EXAMPLES
outer:
    a machine in the outside of the firewall
inner:
    a machine in the inside of the firewall
fwall:
    the firewall on which the stone is executed

stone outer:telnet 10023
    Repeats the telnet protocol to outer.
    Run telnet fwall 10023 on inner.

stone outer:domain/udp domain/udp
    Repeats the DNS query to outer.
    Run nslookup - fwall on inner.

stone outer:ntp/udp ntp/udp
    Repeats the NTP to outer.
    Run ntpdate fwall on inner.

stone localhost:http 443/ssl
    Make WWW server that supports https.
    Access https://fwall/ using a WWW browser.

stone localhost:telnet 10023/ssl
    Make telnet server that supports SSL.
    Run SSLtelnet -z ssl fwall 10023 on inner.

stone proxy 8080
    http proxy

stone outer:110/apop 110
    connect to inner:pop using a mailer that does not support APOP.

Where fwall is a http proxy (port 8080):

stone fwall:8080/http 10023 'POST http://outer:8023 HTTP/1.0'

stone localhost:telnet 8023/http
    Run stones on inner and outer respectively.
    Relays stream over http.

stone fwall:8080/proxy 9080 'Proxy-Authorization: Basic c2VuZ29rdTpoaXJvYWtp'
    for browser that does not support proxy authorization.

HOMEPAGE
The official homepage of stone is:
http://www.gcd.org/sengoku/stone/

COPYRIGHT
All rights about this program stone are reserved by the original author, Hiroaki Sengoku. The program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License (GPL). Furthermore you can link it with openssl.

NO WARRANTY
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY.

AUTHOR
Hiroaki Sengoku
sengoku@gcd.org
http://www.gcd.org/sengoku/