~ubuntu-archive/ubuntu-archive-scripts/trunk

#!/usr/bin/perl

# Name: /usr/local/bin/rrsync (should also have a symlink in /usr/bin)

# Purpose: Restricts rsync to subdirectory declared in .ssh/authorized_keys

# Author: Joe Smith <js-cgi@inwap.com> 30-Sep-2004

# Modified by: Wayne Davison <wayned@samba.org>

use strict;

use Socket;

use Cwd 'abs_path';

use File::Glob ':glob';

# You may configure these values to your liking.  See also the section

# of options if you want to disable any options that rsync accepts.

use constant RSYNC => '/usr/bin/rsync';

use constant LOGFILE => 'rrsync.log';

my $Usage = <<EOM;

Use 'command="$0 [-ro] SUBDIR"'

	in front of lines in $ENV{HOME}/.ssh/authorized_keys

EOM

our $ro = (@ARGV && $ARGV[0] eq '-ro') ? shift : '';	# -ro = Read-Only

our $subdir = shift;

die "$0: No subdirectory specified\n$Usage" unless defined $subdir;

$subdir = abs_path($subdir);

die "$0: Restricted directory does not exist!\n" if $subdir ne '/' && !-d $subdir;

# The client uses "rsync -av -e ssh src/ server:dir/", and sshd on the server

# executes this program when .ssh/authorized_keys has 'command="..."'.

# For example:

# command="rrsync logs/client" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAzGhEeNlPr...

# command="rrsync -ro results" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAmkHG1WCjC...

#

# Format of the envrionment variables set by sshd:

# SSH_ORIGINAL_COMMAND=rsync --server          -vlogDtpr --partial . ARG # push

# SSH_ORIGINAL_COMMAND=rsync --server --sender -vlogDtpr --partial . ARGS # pull

# SSH_CONNECTION=client_addr client_port server_port

my $command = $ENV{SSH_ORIGINAL_COMMAND};

die "$0: Not invoked via sshd\n$Usage"	unless defined $command;

die "$0: SSH_ORIGINAL_COMMAND='$command' is not rsync\n" unless $command =~ s/^rsync\s+//;

die "$0: --server option is not first\n" unless $command =~ /^--server\s/;

our $am_sender = $command =~ /^--server\s+--sender\s/; # Restrictive on purpose!

die "$0 -ro: sending to read-only server not allowed\n" if $ro && !$am_sender;

### START of options data produced by the cull_options script. ###

# These options are the only options that rsync might send to the server,

# and only in the option format that the stock rsync produces.

# To disable a short-named option, add its letter to this string:

our $short_disabled = 's';

our $short_no_arg = 'ACDEHIKLORSWXbcdgklmnoprstuvxz'; # DO NOT REMOVE ANY

our $short_with_num = 'B'; # DO NOT REMOVE ANY

# To disable a long-named option, change its value to a -1.  The values mean:

# 0 = the option has no arg; 1 = the arg doesn't need any checking; 2 = only

# check the arg when receiving; and 3 = always check the arg.

our %long_opt = (

  'append' => 0,

  'backup-dir' => 2,

  'bwlimit' => 1,

  'checksum-seed' => 1,

  'compare-dest' => 2,

  'compress-level' => 1,

  'copy-dest' => 2,

  'copy-unsafe-links' => 0,

  'daemon' => -1,

  'delay-updates' => 0,

  'delete' => 0,

  'delete-after' => 0,

  'delete-before' => 0,

  'delete-delay' => 0,

  'delete-during' => 0,

  'delete-excluded' => 0,

  'existing' => 0,

  'fake-super' => 0,

  'files-from' => 3,

  'force' => 0,

  'from0' => 0,

  'fuzzy' => 0,

  'iconv' => 1,

  'ignore-errors' => 0,

  'ignore-existing' => 0,

  'inplace' => 0,

  'link-dest' => 2,

  'list-only' => 0,

  'log-file' => 3,

  'log-format' => 1,

  'max-delete' => 1,

  'max-size' => 1,

  'min-size' => 1,

  'modify-window' => 1,

  'no-i-r' => 0,

  'no-implied-dirs' => 0,

  'no-r' => 0,

  'no-relative' => 0,

  'no-specials' => 0,

  'numeric-ids' => 0,

  'only-write-batch' => 1,

  'partial' => 0,

  'partial-dir' => 2,

  'remove-sent-files' => $ro ? -1 : 0,

  'remove-source-files' => $ro ? -1 : 0,

  'safe-links' => 0,

  'sender' => 0,

  'server' => 0,

  'size-only' => 0,

  'skip-compress' => 1,

  'specials' => 0,

  'suffix' => 1,

  'super' => 0,

  'temp-dir' => 2,

  'timeout' => 1,

  'use-qsort' => 0,

);

### END of options data produced by the cull_options script. ###

if ($short_disabled ne '') {

    $short_no_arg =~ s/[$short_disabled]//go;

    $short_with_num =~ s/[$short_disabled]//go;

}

$short_no_arg = "[$short_no_arg]" if length($short_no_arg) > 1;

$short_with_num = "[$short_with_num]" if length($short_with_num) > 1;

my $write_log = -f LOGFILE && open(LOG, '>>', LOGFILE);

chdir($subdir) or die "$0: Unable to chdir to restricted dir: $!\n";

my(@opts, @args);

my $in_options = 1;

my $last_opt = '';

my $check_type;

while ($command =~ /((?:[^\s\\]+|\\.[^\s\\]*)+)/g) {

  $_ = $1;

  if ($check_type) {

    push(@opts, check_arg($last_opt, $_, $check_type));

    $check_type = 0;

  } elsif ($in_options) {

    push(@opts, $_);

    if ($_ eq '.') {

      $in_options = 0;

    } else {

      die "$0: invalid option: '-'\n" if $_ eq '-';

      next if /^-$short_no_arg*(e\d*\.\w*)?$/o || /^-$short_with_num\d+$/o;

      my($opt,$arg) = /^--([^=]+)(?:=(.*))?$/;

      my $disabled;

      if (defined $opt) {

	my $ct = $long_opt{$opt};

	last unless defined $ct;

	next if $ct == 0;

	if ($ct > 0) {

	  if (!defined $arg) {

	    $check_type = $ct;

	    $last_opt = $opt;

	    next;

	  }

	  $arg = check_arg($opt, $arg, $ct);

	  $opts[-1] =~ s/=.*/=$arg/;

	  next;

	}

	$disabled = 1;

	$opt = "--$opt";

      } elsif ($short_disabled ne '') {

	$disabled = /^-$short_no_arg*([$short_disabled])/o;

	$opt = "-$1";

      }

      last unless $disabled; # Generate generic failure

      die "$0: option $opt has been disabled on this server.\n";

    }

  } else {

    if ($subdir ne '/') {

      # Validate args to ensure they don't try to leave our restricted dir.

      s#//+#/#g;

      s#^/##;

      s#^$#.#;

      die "Do not use .. in any path!\n" if m#(^|/)\\?\.\\?\.(\\?/|$)#;

    }

    push(@args, bsd_glob($_, GLOB_LIMIT|GLOB_NOCHECK|GLOB_BRACE|GLOB_QUOTE));

  }

}

die "$0: invalid rsync-command syntax or options\n" if $in_options;

@args = ( '.' ) if !@args;

if ($write_log) {

  my ($mm,$hh) = (localtime)[1,2];

  my $host = $ENV{SSH_CONNECTION} || 'unknown';

  $host =~ s/ .*//; # Keep only the client's IP addr

  $host =~ s/^::ffff://;

  $host = gethostbyaddr(inet_aton($host),AF_INET) || $host;

  printf LOG "%02d:%02d %-13s [%s]\n", $hh, $mm, $host, "@opts @args";

  close LOG;

}

# Note: This assumes that the rsync protocol will not be maliciously hijacked.

exec(RSYNC, @opts, @args) or die "exec(rsync @opts @args) failed: $? $!";

sub check_arg

{

  my($opt, $arg, $type) = @_;

  $arg =~ s/\\(.)/$1/g;

  if ($subdir ne '/' && ($type == 3 || ($type == 2 && !$am_sender))) {

    $arg =~ s#//#/#g;

    die "Do not use .. in --$opt; anchor the path at the root of your restricted dir.\n"

      if $arg =~ m#(^|/)\.\.(/|$)#;

    $arg =~ s#^/#$subdir/#;

  }

  $arg;

}