Annotation of loncom/lcuserdel, revision 1.8

1.1       harris41    1: #!/usr/bin/perl
                      2: #
                      3: # lcuserdel
                      4: #
                      5: # Scott Harrison
1.4       harris41    6: # SH: October 27, 2000
                      7: # SH: October 28, 2000
1.5       harris41    8: # SH: October 29, 2000
1.1       harris41    9: 
                     10: use strict;
                     11: 
1.2       harris41   12: # This script is a setuid script (chmod 6755) that should
1.1       harris41   13: # be run by user 'www'.  It DOES NOT delete directories.
                     14: # All it does is remove a user's entries from
                     15: # /etc/passwd, /etc/groups, and /etc/smbpasswd.
1.5       harris41   16: # It also disables user directory access by making the directory
                     17: # to be owned by user=www (as opposed to the former "username").
                     18: # This command only returns an error if it is
                     19: # invoked incorrectly (by passing bad command-line arguments, etc).
1.1       harris41   20: 
1.3       harris41   21: # This script works under the same process control mechanism
                     22: # as lcuseradd and lcpasswd, to make sure that only one of these
                     23: # processes is running at any one time on the system.
1.1       harris41   24: 
                     25: # Standard input usage
                     26: # First line is USERNAME
                     27: 
                     28: # Command-line arguments [USERNAME]
                     29: # Yes, but be very careful here (don't pass shell commands)
                     30: # and this is only supported to allow perl-system calls.
                     31: 
1.2       harris41   32: # Usage within code
                     33: #
1.3       harris41   34: # $exitcode=system("/home/httpd/perl/lcuserdel","NAME")/256;
1.2       harris41   35: # print "uh-oh" if $exitcode;
                     36: 
                     37: # These are the exit codes.
                     38: 
1.1       harris41   39: # Security
                     40: $ENV{'PATH'}=""; # Nullify path information.
                     41: $ENV{'BASH_ENV'}=""; # Nullify shell environment information.
1.2       harris41   42: 
                     43: # Do not print error messages if there are command-line arguments
                     44: my $noprint=0;
                     45: if (@ARGV) {
                     46:     $noprint=1;
                     47: }
                     48: 
1.3       harris41   49: # Read in /etc/passwd, and make sure this process is running from user=www
1.2       harris41   50: open (IN, "</etc/passwd");
                     51: my @lines=<IN>;
                     52: close IN;
                     53: my $wwwid;
                     54: for my $l (@lines) {
                     55:     chop $l;
                     56:     my @F=split(/\:/,$l);
                     57:     if ($F[0] eq 'www') {$wwwid=$F[2];}
                     58: }
                     59: if ($wwwid!=$<) {
                     60:     print("User ID mismatch.  This program must be run as user 'www'\n") unless $noprint;
                     61:     exit 1;
                     62: }
                     63: &disable_root_capability;
                     64: 
1.3       harris41   65: # Handle case of another lcpasswd process
                     66: unless (&try_to_lock("/tmp/lock_lcpasswd")) {
                     67:     print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint;
                     68:     exit 4;
                     69: }
                     70: 
                     71: # Gather input.  Should only be 1 value (user name).
1.2       harris41   72: my @input;
1.3       harris41   73: if (@ARGV==1) {
1.2       harris41   74:     @input=@ARGV;
                     75: }
                     76: elsif (@ARGV) {
1.3       harris41   77:     print("Error. This program needs just 1 command-line argument (username).\n") unless $noprint;
1.2       harris41   78:     exit 2;
                     79: }
                     80: else {
                     81:     @input=<>;
1.3       harris41   82:     if (@input!=1) {
                     83: 	print("Error. Only one line should be entered into standard input.\n") unless $noprint;
1.2       harris41   84: 	exit 3;
                     85:     }
                     86:     map {chop} @input;
                     87: }
1.4       harris41   88: 
                     89: my ($username)=@input;
                     90: $username=~/^(\w+)$/;
                     91: my $safeusername=$1;
                     92: 
1.5       harris41   93: &enable_root_capability;
                     94: 
1.4       harris41   95: # By using the system userdel command:
                     96: # Remove entry from /etc/passwd if it exists
                     97: # Remove entry from /etc/groups if it exists
1.8     ! harris41   98: # I surround with groupdel command to make absolutely sure the group definition disappears.
1.7       harris41   99: system('/usr/sbin/groupdel 2>/dev/null',$safeusername); # ignore error message
1.6       harris41  100: system('/usr/sbin/userdel 2>/dev/null',$safeusername); # ignore error message
1.8     ! harris41  101: system('/usr/sbin/groupdel 2>/dev/null',$safeusername); # ignore error message
1.4       harris41  102: 
                    103: # Remove entry from /etc/smbpasswd if it exists
1.5       harris41  104: my $oldsmbpasswd=`/bin/cat /etc/smbpasswd`;
                    105: my $newsmbpasswd=`/bin/grep -v '^${safeusername}:' /etc/smbpasswd`;
1.4       harris41  106: 
1.5       harris41  107: if ($oldsmbpasswd ne $newsmbpasswd) {
1.6       harris41  108:     open OUT,">/etc/smbpasswd";
                    109:     print OUT $newsmbpasswd;
                    110:     close OUT;
                    111: }
1.4       harris41  112: 
                    113: # Change ownership on directory from username:username to www:www
                    114: # This prevents subsequently added users from having access.
                    115: 
1.5       harris41  116: system('/bin/chown','-R','www:www',"/home/$safeusername");
1.3       harris41  117: 
                    118: &disable_root_capability;
                    119: unlink("/tmp/lock_lcpasswd");
                    120: exit 0;
                    121: 
                    122: # ----------------------------------------------------------- have setuid script run as root
                    123: sub enable_root_capability {
                    124:     if ($wwwid==$>) {
                    125: 	($<,$>)=($>,$<);
                    126: 	($(,$))=($),$();
                    127:     }
                    128:     else {
                    129: 	# root capability is already enabled
                    130:     }
                    131:     return $>;
                    132: }
                    133: 
                    134: # ----------------------------------------------------------- have setuid script run as www
                    135: sub disable_root_capability {
                    136:     if ($wwwid==$<) {
                    137: 	($<,$>)=($>,$<);
                    138: 	($(,$))=($),$();
                    139:     }
                    140:     else {
                    141: 	# root capability is already disabled
                    142:     }
1.2       harris41  143: }
                    144: 
1.3       harris41  145: # ----------------------------------- make sure that another lcpasswd process isn't running
                    146: sub try_to_lock {
                    147:     my ($lockfile)=@_;
                    148:     my $currentpid;
                    149:     my $lastpid;
                    150:     # Do not manipulate lock file as root
                    151:     if ($>==0) {
                    152: 	return 0;
                    153:     }
                    154:     # Try to generate lock file.
                    155:     # Wait 3 seconds.  If same process id is in
                    156:     # lock file, then assume lock file is stale, and
                    157:     # go ahead.  If process id's fluctuate, try
                    158:     # for a maximum of 10 times.
                    159:     for (0..10) {
                    160: 	if (-e $lockfile) {
                    161: 	    open(LOCK,"<$lockfile");
                    162: 	    $currentpid=<LOCK>;
                    163: 	    close LOCK;
                    164: 	    if ($currentpid==$lastpid) {
                    165: 		last;
                    166: 	    }
                    167: 	    sleep 3;
                    168: 	    $lastpid=$currentpid;
                    169: 	}
                    170: 	else {
                    171: 	    last;
                    172: 	}
                    173: 	if ($_==10) {
                    174: 	    return 0;
                    175: 	}
                    176:     }
                    177:     open(LOCK,">$lockfile");
                    178:     print LOCK $$;
                    179:     close LOCK;
                    180:     return 1;
                    181: }
1.2       harris41  182: 
1.1       harris41  183: 

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