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sulogin(8)							   sulogin(8)



NAME

  sulogin - single-user	login program (Enhanced	Security)

SYNOPSIS

  /sbin/sulogin

DESCRIPTION

  The sulogin program is run by	the init process on the	console	terminal when
  entering single-user mode.  The sulogin program checks the system confi-
  guration to determine	whether	entering single-user mode requires entering
  the root password.  If it does not, then sulogin execs /sbin/sh with its
  argv[0] set to "-".  That same exec is also done if the root password	is
  correctly entered.

  The decision to enter	the single-user	mode depends on	the state of the sys-
  tem configuration files.  If the files cannot	be read, then defaults are
  assumed (as described	below).	 Therefore, the	loss of	a configuration	file
  does not prevent access to the system	console	for repairing the problem.

  The sulogin program first checks the /etc/rc.config file for a the
  SECURE_CONSOLE variable.  If such a variable is present, and it is set to a
  true value (either "TRUE", "ON", "YES", or "1"), then	the program asks for
  the root password.  The value	of the SECURE_CONSOLE variable is checked in
  a case-independent fashion, and only a minimal match is necessary.  Thus,
  the value is really checked against the following regular expression:

	^([Tt]|1|[Yy]|[Oo][Nn]).*

  If the SECURE_CONSOLE	variable is present, but does not have one of the
  true values, then sulogin does not ask for the root password,	but simply
  execs	/sbin/sh as previously described.

  If the SECURE_CONSOLE	variable is not	found in the /etc/rc.config file, or
  if that file is missing or unreadable, then an attempt is made to obtain
  the value of the console firmware setting of the SECURE variable, using the
  GSI_PROM_ENV function	of the getsysinfo() system call.  If the check deter-
  mines	the console commands are password- protected, the sulogin program
  requests the root password.

  If sulogin has made the decision to request the root password, it also
  determines whether BASE or ENHANCED security should be used to validate
  that password.  This is done using the value of the SECURITY variable	from
  the /etc/rc.config file, unless that file was	not readable, in which case
  the /etc/sia/matrix.conf file	is read, looking for a line beginning with
  the string "siad_ses_init=", and containing either "(OSFC2," or "(BSD,".
  If the /etc/rc.config	file was readable, but the SECURITY variable was not
  set, then BASE security is assumed.  (This is	how the	/sbin/init.d/security
  script initializes the /etc/sia/matrix.conf file, as well).  If the
  /etc/rc.config file can not be read and the /etc/sia/matrix.conf file
  either can not be read or does not have an appropriate siad_ses_init line,
  then the sulogin program checks to see whether the /etc/passwd file con-
  tains	a valid	entry for root and whether the getespwnam("root") function
  returns a valid extended profile.  If	both profile entries exist, but	only
  one has a valid encrypted password field, that profile (and thus that	secu-
  rity policy) is used.	 If both passwords are valid, the BASE security	pol-
  icy is used.

  Once the sulogin program has determined which	security policy	to use,	it
  checks whether that policy has a valid account entry for user	root (if not
  already checked while	determining which policy to use), and whether that
  entry	has a password that can	be matched.  If	the password is	impossible to
  match, or if no valid	root profile exists, then sulogin prints a warning
  and execs /sbin/sh as	previously described.  For BASE	security, a null
  encrypted password field for root causes the program to exec /sbin/sh
  without complaining.

  If there is a	matchable root password, sulogin prints	out "Single-user root
  login" and prompts for the password.	If the entered password	does not
  match	(after the appropriate encryption if non-null),	the program waits for
  5 seconds (to	deter break-in attempts, displays "Sorry", and re-prompts.
  If the program is interrupted	or receives and	end-of-file condition while
  attempting to	read a password	from the console terminal, it simply exits.
  This normally	causes init to enter multi-user	mode (It depends on system
  configuration	information in /etc/inittab, specifically the entry marked
  with "initdefault", which ships at run-level "3").  This may also cause
  init to prompt for a run level, or to	restart	the sulogin program.

  Finally, if a	password was collected,	and it did match, the exec of
  /sbin/sh is done.  If	that exec fails, the reason for	the failure is
  displayed, and the program sleeps for	5 seconds before exiting.  Upon	exit-
  ing control of the console is	returned to the	init process, as previously
  described for	interrupt or end-of-file.

FILES

  /etc/rc.config
  /etc/sia/matrix.conf
  /etc/passwd
  /tcb/files/auth.db (/tcb/files/auth/r/root)

RELATED	INFORMATION

  login(1), getpwnam(3), getespwnam(3),	dispcrypt(3), matrix.conf(4), init(8)

  Security