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 $ENV{'PATH'} = join(':',@PATH);
  52
  53         print "$#ARGV ".scalar(@ARGV)."\n";
  54 if (scalar(@ARGV) < 2) {
  55     print STDERR "usage: $PROG printer file [user] [system]\n";
  56     exit;
  57 }
  58
  59 $printer = $ARGV[0];
  60 $file    = $ARGV[1];
  61 $user    = $ARGV[2];
  62 $system  = $ARGV[3];
  63
  64 $user = "nobody" unless($user);
  65 $system = `hostname` unless($system);
  66
  67 open(LPSTAT,"/usr/bin/lpstat -t|") || die("Can't get printer list.\n");
  68 @printers = ();
  69 while (<LPSTAT>) {
  70     next unless /^printer (\w+)/;
  71     push(@printers,$1);
  72 }
  73 close LPSTAT;
  74 # Create a hash list
  75 @printers{@printers} = @printers;
  76
  77 # Untaint the printer name
  78 if (defined($prtname = $printers{$printer})) {
  79     $printer = $prtname;
  80 } else {
  81     die("Unknown printer: \"$printer\"\n");
  82 }
  83
  84 if ($> == 0) {          # are we root?
  85     # yes -- then perform a taint checks and possibly do a suid check
  86
  87     # Untaint the file and system names (pretend to filter them)
  88     $file   =   $file =~ /^(.*)/ ? $1 : die("Bad file: $file\n");
  89     $system = $system =~ /^(.*)/ ? $1 : die("Bad system: $system\n");
  90
  91     # Get the valid users
  92     setpwent;
  93     %users = ();
  94     while (@pwe = getpwent()) {
  95         $uids{$pwe[0]} = $pwe[2];
  96         $users{$pwe[2]} = $pwe[0];
  97     }
  98     endpwent();
  99
 100     # Check out the user -- if the user is a real user on this system,
 101     # then become that user so that the  printer header page looks right
 102     # otherwise, remain as the default user (probably "nobody").
 103
 104     if (defined($uid = $uids{$user})) {
 105
 106         # before we change UID, we must ensure that the file is still
 107         # readable after the UID change.
 108         chown($uid, 9, $file);  # make the file owned by the user
 109
 110         # Now, go ahead and become the user
 111         $name = $users{$uid};
 112         $> = $uid;              # become the user
 113         $< = $uid;
 114     } else {                    # do untaint filtering
 115         $name = $user =~ /^(\w+)/ ? $1 : die("Bad user: $user\n");
 116     }
 117 } else {                        # otherwise, just be me
 118     $name = $user;              # whomever that is
 119 }
 120
 121 $lpcommand = "/usr/bin/lp -c -d$printer -t'$name on $system'";
 122
 123 # This code is from the original "psfix" but it has been completely
 124 # rewritten for speed.
 125
 126 if ($PSFIX) {                   # are we running a "psfix"?
 127     open(FILE, $file)           || die("Can't read $file: $!\n");
 128     open(LP, "|$lpcommand -")   || die("Can't open pipe to \"lp\": $!\n");
 129     select(LP);
 130     while (<FILE>) {            #
 131         $_ =~ s/^\004//;                # strip any ctrl-d's
 132         if (/^\e%/) {           # get rid of any non-postscript commands
 133             while (<FILE>) {    # remove text until next %!PS
 134                 s/^\001M//;     # lenmark driver prefixes Ctrl-A M to %!PS
 135                 last if /^%!PS/;
 136             }
 137             last if eof(FILE);
 138         } elsif (/^%%Title:/) { # fix bug in long titles from MS Word
 139             s/.\r$/\r/;         # remove trailing character on the title
 140         } elsif (/^\/VM\?/) {   # remove VM test
 141             print "/VM? { pop } bind def\r\n";
 142             while (<FILE>) { last if /def\r/; }
 143             next;               # don't print
 144         }
 145         print;
 146     }
 147     close FILE;
 148     close LP;
 149 } else {                        # we're not running psfix?
 150     system("$lpcommand $file");
 151 }
 152
 153 if ($file =~ m(^/)) {
 154         # $file is a fully specified path
 155         # Remove the file only if it lives in a directory ending in /tmp.
 156         unlink($file) if ($file =~ m(/tmp/[^/]+$));
 157 } else {
 158         # $file is NOT a fully specified path
 159         # Remove the file only if current directory ends in /tmp.
 160         unlink($file) if (`pwd` =~ m(/tmp$));
 161 }