#!/bin/perl # # Hacked by Alan Stebbens <aks@sgi.com> to setuid to the username if # valid on this system. Written as a secure Perl script. To enable, # # chown root /usr/samba/bin/sambalp # chmod u+s,+x /usr/samba/bin/sambalp # # If setuidshells is not enabled on your system, you must also do this: # # systune -i # nosuidshells = 0 # y # quit # # reboot # # This script will still work as a normal user; it will not try # to setuid in this case. # # If the "$PSFIX" variable is set below... # # Workaround Win95 printer driver/Impressario bug by removing # the PS check for available virtual memory. Note that this # bug appears to be in all Win95 print drivers that generate # PostScript; but is for certain there with a QMS-PS 810 (the # printer type I configure on the Win95-side for printing with # Samba). # # the perl script fixes 3 different bugs. # 1. remove the JCL statements added by some HP printer drivers to the # beginning of the postscript output. # 2. Fix a bug in output from word files with long filenames. A non-printing # character added to the end of the title comment by word is # removed. # 3. The VM fix described above. # # # Modified for Perl4 compatibility. # $PROG = "sambalp"; $PSFIX = 1; # set to 0 if you don't want to run # the "psfix" portion # Untaint the PATH variable @PATH = split(' ',<<EOF); /usr/sbin /usr/bsd /sbin /usr/bin /bin /usr/lib /usr/local/bin EOF $ENV{'PATH'} = join(':',@PATH); if ($#ARGV < 3) { print STDERR "usage: $PROG printer file user system\n"; exit; } $printer = $ARGV[0]; $file = $ARGV[1]; $user = $ARGV[2]; $system = $ARGV[3]; open(LPSTAT,"/usr/bin/lpstat -t|") || die("Can't get printer list.\n"); @printers = (); while (<LPSTAT>) { next unless /^printer (\w+)/; push(@printers,$1); } close LPSTAT; # Create a hash list @printers{@printers} = @printers; # Untaint the printer name if (defined($prtname = $printers{$printer})) { $printer = $prtname; } else { die("Unknown printer: \"$printer\"\n"); } if ($> == 0) { # are we root? # yes -- then perform a taint checks and possibly do a suid check # Untaint the file and system names (pretend to filter them) $file = $file =~ /^(.*)/ ? $1 : die("Bad file: $file\n"); $system = $system =~ /^(.*)/ ? $1 : die("Bad system: $system\n"); # Get the valid users setpwent; %users = (); while (@pwe = getpwent()) { $uids{$pwe[0]} = $pwe[2]; $users{$pwe[2]} = $pwe[0]; } endpwent(); # Check out the user -- if the user is a real user on this system, # then become that user so that the printer header page looks right # otherwise, remain as the default user (probably "nobody"). if (defined($uid = $uids{$user})) { # before we change UID, we must ensure that the file is still # readable after the UID change. chown($uid, 9, $file); # make the file owned by the user # Now, go ahead and become the user $name = $users{$uid}; $> = $uid; # become the user $< = $uid; } else { # do untaint filtering $name = $user =~ /^(\w+)/ ? $1 : die("Bad user: $user\n"); } } else { # otherwise, just be me $name = $user; # whomever that is } $lpcommand = "/usr/bin/lp -c -d$printer -t'$name on $system'"; # This code is from the original "psfix" but it has been completely # rewritten for speed. if ($PSFIX) { # are we running a "psfix"? open(FILE, $file) || die("Can't read $file: $!\n"); open(LP, "|$lpcommand -") || die("Can't open pipe to \"lp\": $!\n"); select(LP); while (<FILE>) { # $_ =~ s/^\004//; # strip any ctrl-d's if (/^\e%/) { # get rid of any non-postscript commands while (<FILE>) { # remove text until next %!PS s/^\001M//; # lenmark driver prefixes Ctrl-A M to %!PS last if /^%!PS/; } last if eof(FILE); } elsif (/^%%Title:/) { # fix bug in long titles from MS Word s/.\r$/\r/; # remove trailing character on the title } elsif (/^\/VM\?/) { # remove VM test print "/VM? { pop } bind def\r\n"; while (<FILE>) { last if /def\r/; } next; # don't print } print; } close FILE; close LP; } else { # we're not running psfix? system("$lpcommand $file"); } if ($file =~ m(^/)) { # $file is a fully specified path # Remove the file only if it lives in a directory ending in /tmp. unlink($file) if ($file =~ m(/tmp/[^/]+$)); } else { # $file is NOT a fully specified path # Remove the file only if current directory ends in /tmp. unlink($file) if (`pwd` =~ m(/tmp$)); }