inndstart(8)						    InterNetNews Documentation						      inndstart(8)

NAME

       inndstart - Start innd

SYNOPSIS

       inndstart [-P port] [-I address] [innd-options]

DESCRIPTION

       The purpose of inndstart is to raise system file descriptor limits, open the privileged news transfer port, and then start innd(8), passing
       it the open file descriptor for the news port.  inndstart is used since only privileged programs can perform those two operations and since
       innd should not run privileged.	It is installed setuid root and drops privileges to the news user (set at configure time) before running
       innd.

       Normally there is no need to run inndstart directly.  Instead, run rc.news(8) as the news user, and it will handle running inndstart appro-
       priately for you.

       Since inndstart is setuid root, it is extremely restrictive about who can run it and what it is willing to do.  See the section on "SECU-
       RITY" for the full details.

       inndstart can only be run by the news user; if run by any other user, it will abort.  It will also only bind to ports 119, 433, or a port
       number given at configure time with --with-innd-port among those ports below 1024, although it can bind to any port above 1024.	This is to
       prevent various security exploits possible by binding to arbitrary privileged ports.

       Before running innd, inndstart cleans out the environment and sets only those environment variables listed in the section on "ENVIRONMENT".

OPTIONS

       -P port
	   Bind to port instead of whatever is specified by port in inn.conf(5).  Note that this is subject to the constraints mentioned above.

       -I address
	   Bind as address instead of whatever is specified by bindaddress in inn.conf(5).  The default behavior is to bind to INADDR_ANY, and
	   that's what's desired almost all the time.  This option, and the inn.conf(5) parameter, may be useful if the machine has multiple
	   interface cards and innd should only be listening on a particular one.

       All other options given on the command line are passed verbatim to innd.  In addition, inndstart will give the -p option to innd, specify-
       ing the file descriptor of the open network socket.

SECURITY

       inndstart is setuid root, and therefore an expected point of attack.  It has therefore been carefully written with security in mind.  In a
       normal INN installation, it is installed setuid root and executable only by users in the news group.

       Ideally, everything about inndstart's operations would be hard-coded so that it could not be modified.  Fighting against this desire, how-
       ever, is the ideal that as much of INN's operation as possible should be configurable at run-time using inn.conf(5), and the news system
       should be able to an alternate inn.conf by setting INNCONF to the path to that file before starting any programs.  The configuration data
       therefore can't be trusted.

       The security model used is:

       o inndstart can only be executed by the news user and news group, as determined at configure time and compiled into inndstart as constants.
	 Similarly, inndstart will always setuid() and setgid() to those users before running innd.  This is to prevent a user other than news but
	 in the news group from using inndstart to leverage that access into access to the news account.

       o As mentioned above, inndstart will only bind to a very limited set of ports below 1024.  There are various attacks that can be performed
	 using random low-numbered ports, including exploits of the rsh family of commands on some systems.

       o inndstart does as little as possible as root, dropping privileges before performing any operations that do not require elevated privi-
	 leges.

       This program therefore gives the news user the ability to revoke system file descriptor limits and bind to the news port, and nothing else.

DIAGNOSTICS

       inndstart may log the following messages to syslog (like the rest of INN, syslog is the best place to find detailed debugging information):

       can't bind: %s
	   (Fatal) Unable to bind to the designated port.  This usually means that something else is already running on the news port.	Check with
	   netstat(8) and make sure that inetd(8) doesn't think it's running a service on the same port you're trying to run innd on.

       can't exec %s: %s
	   (Fatal) inndstart was unable to execute innd.  Make sure that pathbin is set correctly in inn.conf and that innd is located in that
	   directory and is executable by the news user.

       can't getrlimit(NOFILE)
	   (Warning) Unable to obtain the current system resource limit on file descriptors.  Chances are something is wrong with the *rlimit()
	   functions.  The file descriptor limit was left unchanged from the system default.

       can't open socket: %s
	   (Fatal) Something went wrong in creating the network socket.  Chances are your system is out of resources of some kind.

       can't setgid(%d): %s
	   (Fatal) Dropping privileges to the news group failed for some reason.

       can't setgroups: %s
	   (Warning) Dropping all supplemental groups except the news group failed for some reason, and the process group membership was left
	   unchanged.  This message may indicate a minor security hole if the news user is in extra groups.

       can't setrlimit(NOFILE, %d)
	   (Warning) Unable to set the system file descriptor limit to the specified value.  Either that value is too high for your system or
	   something else went wrong.  The file descriptor limit was left unchanged.  Try changing rlimitnofile in inn.conf to a smaller value.

       can't setsockopt: %s
	   (Warning) inndstart attempts to set SO_REUSEADDR so that if innd exits, it can be restarted again immediately without waiting for the
	   port to time out.  For some reason, this failed, and that option was not set on the port.

       can't setuid(%d): %s
	   (Fatal) Dropping privileges to the news user failed for some reason.

       can't stat pathrun (%s): %s
	   (Fatal) pathrun as specified in inn.conf doesn't exist.

       getgrnam(%s) failed
	   (Fatal) Unable to determine the GID for the compiled-in news group.	Is the news group listed in /etc/group?

       getpwnam(%s) failed
	   (Fatal) Unable to determine the UID for the compiled-in news user.  Is the news user listed in /etc/passwd?

       invalid address %s
	   (Fatal) -I was specified on the command line, but the argument wasn't a valid address.  Addresses must be given as numeric IP
	   addresses.

       invalid bindaddress in inn.conf (%s)
	   (Fatal) The bindaddress specified in inn.conf could not be converted to an IP address.  See inn.conf(5) for more information about
	   valid values.

       invalid port %s
	   (Fatal) -P was specified on the command line, but the argument wasn't a valid port.	Ports must be port numbers; service names are not
	   allowed.

       missing address after -I
	   (Fatal) -I was given on the command line, but no address was given after the option.

       missing port after -P
	   (Fatal) -P was given on the command line, but no port was given after the option.

       pathrun (%s) not a directory
	   (Fatal) pathrun as specified in inn.conf isn't a directory.	This is where innd will create its local control socket; it should always
	   be a directory.

       pathrun (%s) owned by group %d, not %s (%d)
	   (Fatal) pathrun specified in inn.conf must be owned by the news group.  This is checked for security reasons.

       pathrun (%s) owned by user %d, not %s (%d)
	   (Fatal) pathrun specified in inn.conf must be owned by the news user.  This is checked for security reasons.

       ran by GID %d, who isn't %s (%d)
	   (Fatal) Someone not in the news group attempted to run inndstart.  If you were running inndstart as the news user, make sure that the
	   news user's default group is the news group you picked at compile time (`news' by default).

       ran by UID %d, who isn't %s (%d)
	   (Fatal) Someone other than the news user attempted to run inndstart.  inndstart may only be run by the news user for security reasons.

       seteuid(%d) failed: %s
	   (Fatal) Unable to change the effective UID.	This usually means that inndstart was installed with the wrong permissions.  If it does
	   have the correct permissions (setuid root) and seteuid() to root (UID 0) is failing, this may mean that your system has seteuid() but
	   doesn't have support for POSIX saved UIDs.  If this is the case, please report this to the INN maintainers.

       setreuid(%d, %d) failed: %s
	   (Fatal) Unable to change the real and effective UIDs.  This message usually means that inndstart was installed with the wrong permis-
	   sions.

       tried to bind to port %d
	   (Fatal) inndstart was told to bind to a low numbered port (under 1024) other than 119, 433, or a port number given at configure time.
	   This is not allowed for security reasons.

EXAMPLES

       Normally, inndstart is never run directly.  However, a simple way to just restart innd without running any other auxilliary programs or
       performing any of the other checks done by rc.news(8) is to just run:

	   inndstart

       as the news user.

       To start innd on port 433, passing it the `-c21' option, use:

	   inndstart -P433 -c21

ENVIRONMENT

       One environment variable affects the operation of inndstart itself:

       INNCONF The full path to the inn.conf(5) file to read, rather than the default.	This can be used to run multiple copies of INN on the same
	       machine with different settings.

       When executing innd, inndstart cleans out the entire environmnent and sets only the following variables:

       BIND_INADDR
	       Passed verbatim from inndstart's environment.  This is apparently used on Linux.

       HOME    Set to pathnews from inn.conf.

       LOGNAME Set to the news master, as determined at configure time.

       PATH    Set to pathbin from inn.conf, pathetc from inn.conf, and then /bin, /usr/bin, and /usr/ucb in that order.

       SHELL   Set to the path to the system Bourne shell as determined by configure (probably /bin/sh).

       TMPDIR  Set to pathtmp from inn.conf.

       TZ      Passed verbatim from inndstart's environment.

       USER    Set to the news master, as determined at configure time.

FILES

       inn.conf
	   Read for pathnews, pathbin, pathrun, pathtmp, rlimitnofile, bindaddress, and port.

       pathbin/innd
	   The binary that is executed as innd and passed the open network socket.

       pathrun
	   Checked for existence and the right ownership.

HISTORY

       Written by Russ Allbery <rra@stanford.edu> for InterNetNews.

       $Id: inndstart.8,v 1.2 1999/10/23 16:25:47 rra Exp $

SEE ALSO

       inn.conf(5), innd(8)

3rd Berkeley Distribution					      INN 2.3							      inndstart(8)