Return to lcpasswd CVS log

Up to [LON-CAPA] / loncom

I'm trying to make the setuid synchronizing password for loncapa here. -Scott

    1: #!/usr/bin/perl
    2: 
    3: use strict;
    4: 
    5: # Scott Harrison
    6: # October 27, 2000
    7: 
    8: # This script is a setuid script that should
    9: # be run by user 'www'.
   10: 
   11: # Standard input usage
   12: # First line is USERNAME
   13: # Second line is CURRENT PASSWORD
   14: # Third line is NEW PASSWORD
   15: 
   16: # Security
   17: $ENV{'PATH'}=""; # Nullify path information.
   18: $ENV{'BASH_ENV'}=""; # Nullify shell environment information.
   19: 
   20: open (IN, "</etc/passwd");
   21: my @lines=<IN>;
   22: close IN;
   23: my $wwwid;
   24: for my $l (@lines) {
   25:     chop $l;
   26:     my @F=split(/\:/,$l);
   27:     if ($F[0] eq 'www') {$wwwid=$F[2];}
   28: }
   29: if ($wwwid!=$<) {
   30:     print("User ID mismatch.  This program must be run as user 'www'\n");
   31:     exit 0;
   32: }
   33: if (@ARGV) {
   34:     print("Error. This program does not accept command-line arguments.\n");
   35:     exit 0;
   36: }
   37: 
   38: # Gather input from standard input.  Should only be 3 lines.
   39: my @input=<>;
   40: if (@input!=3) {
   41:     print("Error. Three lines need to be entered into standard input.\n");
   42:     exit 0;
   43: }
   44: 
   45: # Handle case of another lcpasswd process
   46: unless (&try_to_lock("/tmp/lock_lcpasswd")) {
   47:     print "Error. Too many other simultaneous password change requests being made.\n";
   48:     exit 0;
   49: }
   50: 
   51: my ($username,$oldpwd,$newpwd)=map {chop; $_} @input;
   52: 
   53: # Grab the line corresponding to username
   54: my ($userid,$useroldcryptpwd);
   55: my @F; my @U;
   56: for my $l (@lines) {
   57:     @F=split(/\:/,$l);
   58:     if ($F[0] eq $username) {($userid,$useroldcryptpwd)=($F[2],$F[1]); @U=@F;}
   59: }
   60: 
   61: # Verify existence of user
   62: if (!defined($userid)) {
   63:     print "Error. User $username does not exist.\n";
   64:     exit 0;
   65: }
   66: 
   67: # Verify password entry
   68: if (crypt($oldpwd,$useroldcryptpwd) ne $useroldcryptpwd) {
   69:     print "Error. Invalid entry of current password.\n";
   70:     exit 0;
   71: }
   72: 
   73: # Construct new password entry
   74: my $newcryptpwd=crypt($newpwd,$newpwd);
   75: $U[1]=$newcryptpwd;
   76: my $userline=join(":",@U);
   77: print $newcryptpwd;
   78: print $userline;
   79: #my $rootid=&enable_root_capability;
   80: #if ($rootid!=0) {
   81: #    print "Error.  Root was not successfully enabled.\n";
   82: #    exit 0;
   83: #}
   84: # open SAMBAPASSWORDFILE, ">/etc/smbpasswd";
   85: 	($<,$>)=($>,$<);
   86: 	($(,$))=($),$();
   87: open PASSWORDFILE, "/tmp/passwd2" or die("Cannot open /etc/passwd!");
   88: for my $l (@lines) {
   89:     @F=split(/\:/,$l);
   90:     if ($F[0] eq $username) {print PASSWORDFILE "$userline\n";}
   91:     else {print PASSWORDFILE "$l\n";}
   92: }
   93: close PASSWORDFILE;
   94: # close SAMBAPASSWORDFILE;
   95: &disable_root_capability;
   96: unlink("/tmp/lock_lcpasswd");
   97: 
   98: sub enable_root_capability {
   99:     if ($wwwid==$<) {
  100: 	($<,$>)=($>,$<);
  101: 	($(,$))=($),$();
  102:     }
  103:     else {
  104: 	# root capability is already enabled
  105:     }
  106:     return $<;
  107: }
  108: 
  109: sub disable_root_capability {
  110:     if ($wwwid==$>) {
  111: 	($<,$>)=($>,$<);
  112: 	($(,$))=($),$();
  113:     }
  114:     else {
  115: 	# root capability is already disabled
  116:     }
  117: }
  118: 
  119: sub try_to_lock {
  120:     my ($lockfile)=@_;
  121:     my $currentpid;
  122:     my $lastpid;
  123:     for (0..10) {
  124: 	if (-e $lockfile) {
  125: 	    open(LOCK,"<$lockfile");
  126: 	    $currentpid=<LOCK>;
  127: 	    close LOCK;
  128: 	    if ($currentpid==$lastpid) {
  129: 		last;
  130: 	    }
  131: 	    sleep 3;
  132: 	    $lastpid=$currentpid;
  133: 	}
  134: 	else {
  135: 	    last;
  136: 	}
  137: 	if ($_==10) {
  138: 	    return 0;
  139: 	}
  140:     }
  141:     open(LOCK,">$lockfile");
  142:     print LOCK $$;
  143:     close LOCK;
  144:     return 1;
  145: }