packaging/SGI/sambalp

   1 #!/bin/perl
   2 #
   3 # Hacked by Alan Stebbens <aks@sgi.com> to setuid to the username if
   4 # valid on this system.  Written as a secure Perl script.  To enable,
   5 #
   6 #       chown root /usr/samba/bin/sambalp
   7 #       chmod u+s,+x /usr/samba/bin/sambalp
   8 #
   9 # If setuidshells is not enabled on your system, you must also do this:
  10 #
  11 #       systune -i
  12 #       nosuidshells = 0
  13 #       y
  14 #       quit
  15 #
  16 #       reboot
  17 #
  18 # This script will still work as a normal user; it will not try
  19 # to setuid in this case.
  20 #
  21 # If the "$PSFIX" variable is set below...
  22 #
  23 # Workaround Win95 printer driver/Impressario bug by removing
  24 # the PS check for available virtual memory.  Note that this
  25 # bug appears to be in all Win95 print drivers that generate
  26 # PostScript; but is for certain there with a QMS-PS 810 (the
  27 # printer type I configure on the Win95-side for printing with
  28 # Samba).
  29 #
  30 # the perl script fixes 3 different bugs.
  31 # 1. remove the JCL statements added by some HP printer drivers to the
  32 # beginning of the postscript output.
  33 # 2. Fix a bug in output from word files with long filenames. A non-printing
  34 # character added to the end of the title comment by word is
  35 # removed.
  36 # 3. The VM fix described above.
  37 #
  38 #
  39 # Modified for Perl4 compatibility.
  40 #
  41
  42 $PROG = "sambalp";
  43
  44 $PSFIX = 1;                     # set to 0 if you don't want to run
  45                                 # the "psfix" portion
  46
  47 # Untaint the PATH variable
  48 @PATH = split(' ',<<EOF);
  49         /usr/sbin /usr/bsd /sbin /usr/bin /bin /usr/lib /usr/local/bin
  50 EOF
  51 $ENV{'PATH'} = join(':',@PATH);
  52
  53 if ($#ARGV < 3) {
  54     print STDERR "usage: $PROG printer file user system\n";
  55     exit;
  56 }
  57
  58 $printer = $ARGV[0];
  59 $file    = $ARGV[1];
  60 $user    = $ARGV[2];
  61 $system  = $ARGV[3];
  62
  63 open(LPSTAT,"/usr/bin/lpstat -t|") || die("Can't get printer list.\n");
  64 @printers = ();
  65 while (<LPSTAT>) {
  66     next unless /^printer (\w+)/;
  67     push(@printers,$1);
  68 }
  69 close LPSTAT;
  70 # Create a hash list
  71 @printers{@printers} = @printers;
  72
  73 # Untaint the printer name
  74 if (defined($prtname = $printers{$printer})) {
  75     $printer = $prtname;
  76 } else {
  77     die("Unknown printer: \"$printer\"\n");
  78 }
  79
  80 if ($> == 0) {          # are we root?
  81     # yes -- then perform a taint checks and possibly do a suid check
  82
  83     # Untaint the file and system names (pretend to filter them)
  84     $file   =   $file =~ /^(.*)/ ? $1 : die("Bad file: $file\n");
  85     $system = $system =~ /^(.*)/ ? $1 : die("Bad system: $system\n");
  86
  87     # Get the valid users
  88     setpwent;
  89     %users = ();
  90     while (@pwe = getpwent()) {
  91         $uids{$pwe[0]} = $pwe[2];
  92         $users{$pwe[2]} = $pwe[0];
  93     }
  94     endpwent();
  95
  96     # Check out the user -- if the user is a real user on this system,
  97     # then become that user so that the  printer header page looks right
  98     # otherwise, remain as the default user (probably "nobody").
  99
 100     if (defined($uid = $uids{$user})) {
 101
 102         # before we change UID, we must ensure that the file is still
 103         # readable after the UID change.
 104         chown($uid, 9, $file);  # make the file owned by the user
 105
 106         # Now, go ahead and become the user
 107         $name = $users{$uid};
 108         $> = $uid;              # become the user
 109         $< = $uid;
 110     } else {                    # do untaint filtering
 111         $name = $user =~ /^(\w+)/ ? $1 : die("Bad user: $user\n");
 112     }
 113 } else {                        # otherwise, just be me
 114     $name = $user;              # whomever that is
 115 }
 116
 117 $lpcommand = "/usr/bin/lp -c -d$printer -t'$name on $system'";
 118
 119 # This code is from the original "psfix" but it has been completely
 120 # rewritten for speed.
 121
 122 if ($PSFIX) {                   # are we running a "psfix"?
 123     open(FILE, $file)           || die("Can't read $file: $!\n");
 124     open(LP, "|$lpcommand -")   || die("Can't open pipe to \"lp\": $!\n");
 125     select(LP);
 126     while (<FILE>) {            #
 127         $_ =~ s/^\004//;                # strip any ctrl-d's
 128         if (/^\e%/) {           # get rid of any non-postscript commands
 129             while (<FILE>) {    # remove text until next %!PS
 130                 s/^\001M//;     # lenmark driver prefixes Ctrl-A M to %!PS
 131                 last if /^%!PS/;
 132             }
 133             last if eof(FILE);
 134         } elsif (/^%%Title:/) { # fix bug in long titles from MS Word
 135             s/.\r$/\r/;         # remove trailing character on the title
 136         } elsif (/^\/VM\?/) {   # remove VM test
 137             print "/VM? { pop } bind def\r\n";
 138             while (<FILE>) { last if /def\r/; }
 139             next;               # don't print
 140         }
 141         print;
 142     }
 143     close FILE;
 144     close LP;
 145 } else {                        # we're not running psfix?
 146     system("$lpcommand $file");
 147 }
 148
 149 if ($file =~ m(^/)) {
 150         # $file is a fully specified path
 151         # Remove the file only if it lives in a directory ending in /tmp.
 152         unlink($file) if ($file =~ m(/tmp/[^/]+$));
 153 } else {
 154         # $file is NOT a fully specified path
 155         # Remove the file only if current directory ends in /tmp.
 156         unlink($file) if (`pwd` =~ m(/tmp$));
 157 }