sulogin(8)						      System Manager's Manual							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 sys-
       tem configuration 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 system 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  vari-
       able  is  checked in a case-independent fashion, and only a minimal match is necessary.	Thus, the value is really checked against the fol-
       lowing 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 determines 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 vali-
       date 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 contains 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  security
       policy) is used.  If both passwords are valid, the BASE security policy 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 exiting 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 delim off

																	sulogin(8)