Annotation of loncom/lcuserdel, revision 1.10

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: 
1.10    ! harris41   28: # Valid user names must consist of ascii
        !            29: # characters that are alphabetical characters
        !            30: # (A-Z,a-z), numeric (0-9), or the underscore
        !            31: # mark (_). (Essentially, the perl regex \w).
        !            32: 
1.1       harris41   33: # Command-line arguments [USERNAME]
                     34: # Yes, but be very careful here (don't pass shell commands)
                     35: # and this is only supported to allow perl-system calls.
                     36: 
1.2       harris41   37: # Usage within code
                     38: #
1.3       harris41   39: # $exitcode=system("/home/httpd/perl/lcuserdel","NAME")/256;
1.2       harris41   40: # print "uh-oh" if $exitcode;
                     41: 
                     42: # These are the exit codes.
1.9       harris41   43: # ( (0,"ok"),
                     44: #   (1,"User ID mismatch.  This program must be run as user 'www'"),
                     45: #   (2,"Error. Too many other simultaneous password change requests being made."),
                     46: #   (3,"Error. Only one line should be entered into standard input."),
                     47: #   (4,"Error. This program needs just 1 command-line argument (username).") )
1.2       harris41   48: 
1.1       harris41   49: # Security
                     50: $ENV{'PATH'}=""; # Nullify path information.
                     51: $ENV{'BASH_ENV'}=""; # Nullify shell environment information.
1.2       harris41   52: 
                     53: # Do not print error messages if there are command-line arguments
                     54: my $noprint=0;
                     55: if (@ARGV) {
                     56:     $noprint=1;
                     57: }
                     58: 
1.3       harris41   59: # Read in /etc/passwd, and make sure this process is running from user=www
1.2       harris41   60: open (IN, "</etc/passwd");
                     61: my @lines=<IN>;
                     62: close IN;
                     63: my $wwwid;
                     64: for my $l (@lines) {
                     65:     chop $l;
                     66:     my @F=split(/\:/,$l);
                     67:     if ($F[0] eq 'www') {$wwwid=$F[2];}
                     68: }
                     69: if ($wwwid!=$<) {
                     70:     print("User ID mismatch.  This program must be run as user 'www'\n") unless $noprint;
                     71:     exit 1;
                     72: }
                     73: &disable_root_capability;
                     74: 
1.3       harris41   75: # Handle case of another lcpasswd process
                     76: unless (&try_to_lock("/tmp/lock_lcpasswd")) {
                     77:     print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint;
                     78:     exit 4;
                     79: }
                     80: 
                     81: # Gather input.  Should only be 1 value (user name).
1.2       harris41   82: my @input;
1.3       harris41   83: if (@ARGV==1) {
1.2       harris41   84:     @input=@ARGV;
                     85: }
                     86: elsif (@ARGV) {
1.3       harris41   87:     print("Error. This program needs just 1 command-line argument (username).\n") unless $noprint;
1.9       harris41   88:     unlink('/tmp/lock_lcpasswd');
1.2       harris41   89:     exit 2;
                     90: }
                     91: else {
                     92:     @input=<>;
1.3       harris41   93:     if (@input!=1) {
                     94: 	print("Error. Only one line should be entered into standard input.\n") unless $noprint;
1.9       harris41   95: 	unlink('/tmp/lock_lcpasswd');
1.2       harris41   96: 	exit 3;
                     97:     }
                     98:     map {chop} @input;
                     99: }
1.4       harris41  100: 
                    101: my ($username)=@input;
                    102: $username=~/^(\w+)$/;
                    103: my $safeusername=$1;
1.10    ! harris41  104: if ($username ne $safeusername) {
        !           105:     print "Error. The user name specified has invalid characters.\n";
        !           106:     unlink('/tmp/lock_lcpasswd');
        !           107:     exit 9;
        !           108: }
1.4       harris41  109: 
1.5       harris41  110: &enable_root_capability;
                    111: 
1.4       harris41  112: # By using the system userdel command:
                    113: # Remove entry from /etc/passwd if it exists
                    114: # Remove entry from /etc/groups if it exists
1.8       harris41  115: # I surround with groupdel command to make absolutely sure the group definition disappears.
1.7       harris41  116: system('/usr/sbin/groupdel 2>/dev/null',$safeusername); # ignore error message
1.6       harris41  117: system('/usr/sbin/userdel 2>/dev/null',$safeusername); # ignore error message
1.8       harris41  118: system('/usr/sbin/groupdel 2>/dev/null',$safeusername); # ignore error message
1.4       harris41  119: 
                    120: # Remove entry from /etc/smbpasswd if it exists
1.5       harris41  121: my $oldsmbpasswd=`/bin/cat /etc/smbpasswd`;
                    122: my $newsmbpasswd=`/bin/grep -v '^${safeusername}:' /etc/smbpasswd`;
1.4       harris41  123: 
1.5       harris41  124: if ($oldsmbpasswd ne $newsmbpasswd) {
1.6       harris41  125:     open OUT,">/etc/smbpasswd";
                    126:     print OUT $newsmbpasswd;
                    127:     close OUT;
                    128: }
1.4       harris41  129: 
                    130: # Change ownership on directory from username:username to www:www
                    131: # This prevents subsequently added users from having access.
                    132: 
1.5       harris41  133: system('/bin/chown','-R','www:www',"/home/$safeusername");
1.3       harris41  134: 
                    135: &disable_root_capability;
                    136: unlink("/tmp/lock_lcpasswd");
                    137: exit 0;
                    138: 
                    139: # ----------------------------------------------------------- have setuid script run as root
                    140: sub enable_root_capability {
                    141:     if ($wwwid==$>) {
                    142: 	($<,$>)=($>,$<);
                    143: 	($(,$))=($),$();
                    144:     }
                    145:     else {
                    146: 	# root capability is already enabled
                    147:     }
                    148:     return $>;
                    149: }
                    150: 
                    151: # ----------------------------------------------------------- have setuid script run as www
                    152: sub disable_root_capability {
                    153:     if ($wwwid==$<) {
                    154: 	($<,$>)=($>,$<);
                    155: 	($(,$))=($),$();
                    156:     }
                    157:     else {
                    158: 	# root capability is already disabled
                    159:     }
1.2       harris41  160: }
                    161: 
1.3       harris41  162: # ----------------------------------- make sure that another lcpasswd process isn't running
                    163: sub try_to_lock {
                    164:     my ($lockfile)=@_;
                    165:     my $currentpid;
                    166:     my $lastpid;
                    167:     # Do not manipulate lock file as root
                    168:     if ($>==0) {
                    169: 	return 0;
                    170:     }
                    171:     # Try to generate lock file.
                    172:     # Wait 3 seconds.  If same process id is in
                    173:     # lock file, then assume lock file is stale, and
                    174:     # go ahead.  If process id's fluctuate, try
                    175:     # for a maximum of 10 times.
                    176:     for (0..10) {
                    177: 	if (-e $lockfile) {
                    178: 	    open(LOCK,"<$lockfile");
                    179: 	    $currentpid=<LOCK>;
                    180: 	    close LOCK;
                    181: 	    if ($currentpid==$lastpid) {
                    182: 		last;
                    183: 	    }
                    184: 	    sleep 3;
                    185: 	    $lastpid=$currentpid;
                    186: 	}
                    187: 	else {
                    188: 	    last;
                    189: 	}
                    190: 	if ($_==10) {
                    191: 	    return 0;
                    192: 	}
                    193:     }
                    194:     open(LOCK,">$lockfile");
                    195:     print LOCK $$;
                    196:     close LOCK;
                    197:     return 1;
                    198: }
1.2       harris41  199: 
1.1       harris41  200: 

FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>