Blame - ssh-rand-helper.8 - platform/external/openssh

blob: af5a72fcbb9bb373276e6f583ae39316a975dc74 [file] [log] [blame]

Damien Miller	9f74105	2007-01-22 12:44:53 +1100	[diff] [blame]	1	.\" $Id: ssh-rand-helper.8,v 1.3 2007/01/22 01:44:53 djm Exp $
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	2	.\"
				3	.\" Copyright (c) 2002 Damien Miller. All rights reserved.
				4	.\"
				5	.\" Redistribution and use in source and binary forms, with or without
				6	.\" modification, are permitted provided that the following conditions
				7	.\" are met:
				8	.\" 1. Redistributions of source code must retain the above copyright
				9	.\" notice, this list of conditions and the following disclaimer.
				10	.\" 2. Redistributions in binary form must reproduce the above copyright
				11	.\" notice, this list of conditions and the following disclaimer in the
				12	.\" documentation and/or other materials provided with the distribution.
				13	.\"
				14	.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
				15	.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
				16	.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
				17	.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
				18	.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
				19	.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
				20	.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
				21	.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
				22	.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
				23	.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
				24	.\"
				25	.Dd April 14, 2002
				26	.Dt SSH-RAND-HELPER 8
				27	.Os
				28	.Sh NAME
				29	.Nm ssh-rand-helper
Damien Miller	9f74105	2007-01-22 12:44:53 +1100	[diff] [blame]	30	.Nd random number gatherer for OpenSSH
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	31	.Sh SYNOPSIS
				32	.Nm ssh-rand-hlper
				33	.Op Fl vxXh
				34	.Op Fl b Ar bytes
				35	.Sh DESCRIPTION
				36	.Nm
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	37	is a small helper program used by
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	38	.Xr ssh 1 ,
				39	.Xr ssh-add 1 ,
				40	.Xr ssh-agent 1 ,
				41	.Xr ssh-keygen 1 ,
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	42	.Xr ssh-keyscan 1
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	43	and
				44	.Xr sshd 8
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	45	to gather random numbers of cryptographic quality if the
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	46	.Xr openssl 4
				47	library has not been configured to provide them itself.
				48	.Pp
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	49	Normally
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	50	.Nm
				51	will generate a strong random seed and provide it to the calling
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	52	program via standard output. If standard output is a tty,
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	53	.Nm
				54	will instead print the seed in hexidecimal format unless told otherwise.
				55	.Pp
				56	.Nm
				57	will by default gather random numbers from the system commands listed
				58	in
				59	.Pa /etc/ssh/ssh_prng_cmds .
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	60	The output of each of the commands listed will be hashed and used to
				61	generate a random seed for the calling program.
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	62	.Nm
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	63	will also store seed files in
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	64	.Pa ~/.ssh/prng_seed
				65	between executions.
				66	.Pp
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	67	Alternately,
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	68	.Nm
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	69	may be configured at build time to collect random numbers from a
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	70	EGD/PRNGd server via a unix domain or localhost tcp socket.
				71	.Pp
Damien Miller	a8e06ce	2003-11-21 23:48:55 +1100	[diff] [blame]	72	This program is not intended to be run by the end-user, so the few
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	73	commandline options are for debugging purposes only.
				74	.Bl -tag -width Ds
				75	.It Fl b Ar bytes
				76	Specify the number of random bytes to include in the output.
				77	.It Fl x
				78	Output a hexidecimal instead of a binary seed.
				79	.It Fl X
				80	Force output of a binary seed, even if standard output is a tty
				81	.It Fl v
				82	Turn on debugging message. Multiple
				83	.Fl v
				84	options will increase the debugging level.
Damien Miller	9f74105	2007-01-22 12:44:53 +1100	[diff] [blame]	85	.It Fl h
Damien Miller	32e4818	2002-04-14 19:27:12 +1000	[diff] [blame]	86	Display a summary of options.
				87	.El
				88	.Sh AUTHORS
				89	Damien Miller <djm@mindrot.org>
				90	.Sh SEE ALSO
				91	.Xr ssh 1 ,
				92	.Xr ssh-add 1 ,
				93	.Xr ssh-keygen 1 ,
				94	.Xr sshd 8