# 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> 12-Jan-2005
+# 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
-my $ro = (@ARGV and $ARGV[0] eq '-ro') ? shift : ''; # -ro = Read-Only
-my $subdir = shift;
-die "No subdirectory specified\n$Usage" unless defined $subdir;
+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="..."'.
# command="rrsync -ro results" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAmkHG1WCjC...
#
# Format of the envrionment variables set by sshd:
-# SSH_ORIGINAL_COMMAND=rsync --server -vlogDtpr --partial . dir # push
-# SSH_ORIGINAL_COMMAND=rsync --server --sender -vlogDtpr --partial . dir # pull
+# 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 = $ENV{SSH_ORIGINAL_COMMAND};
-die "Not invoked via sshd\n$Usage" unless defined $command;
-die "SSH_ORIGINAL_COMMAND='$command' is not rsync\n" unless $command =~ /^rsync\s/;
-die "$0 -ro: sending to read-only server not allowed\n"
- if $ro and $command !~ /^rsync --server --sender /;
-die "$0 -ro: use of --remove-sent-files with read-only server not allowed\n"
- if $ro and $command =~ /\s--remove-sent-files/;
-
-my ($cmd,$dir) = $command =~ /^(rsync\s+(?:-[-a-zA-Z]+\s+)+\.) ?("[^"]*"|[^\s"]*)$/;
-die "$0: invalid rsync-command syntax or options\n" if !defined $cmd;
-
-# Enforce default of $subdir instead of the normal $HOME default.
-my $orig = $dir;
-my @dirs;
-$dir =~ s/^"(.*?)"$/$1/;
-$dir =~ s/^\s+//;
-$dir =~ s/\s+$//;
-foreach (split(/(?<!\\)\s+/, $dir)) {
- s/\\(\s)/$1/g; # Unescape any escaped whitespace
- if ($subdir eq '/') { # Less checking for '/' access
- $dir = '/' if $dir eq '';
+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,
+ 'delete-missing-args' => 0,
+ 'existing' => 0,
+ 'fake-super' => 0,
+ 'files-from' => 3,
+ 'force' => 0,
+ 'from0' => 0,
+ 'fuzzy' => 0,
+ 'groupmap' => 1,
+ 'iconv' => 1,
+ 'ignore-errors' => 0,
+ 'ignore-existing' => 0,
+ 'ignore-missing-args' => 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-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' => $ro ? -1 : 0,
+ 'safe-links' => 0,
+ 'sender' => 0,
+ 'server' => 0,
+ 'size-only' => 0,
+ 'skip-compress' => 1,
+ 'specials' => 0,
+ 'stats' => 0,
+ 'suffix' => 1,
+ 'super' => 0,
+ 'temp-dir' => 2,
+ 'timeout' => 1,
+ 'use-qsort' => 0,
+ 'usermap' => 1,
+);
+
+### END of options data produced by the cull_options script. ###
+
+if ($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 {
- s#^/##; # Don't allow absolute paths
- $_ = "$subdir/$_" unless m#^\Q$subdir\E(/|$)#;
- 1 while s#/\.\.(/|$)#/__/#g; # Don't allow foo/../../etc
+ if ($subdir ne '/') {
+ # Validate args to ensure they don't try to leave our restricted dir.
+ s{//+}{/}g;
+ s{^/}{};
+ s{^$}{.};
+ die "$0: do not use .. in any path!\n" if m{(^|/)\\?\.\\?\.(\\?/|$)};
+ }
+ push(@args, bsd_glob($_, GLOB_LIMIT|GLOB_NOCHECK|GLOB_BRACE|GLOB_QUOTE));
}
- tr#-_/a-zA-Z0-9.,+@^%: #_#c; # Don't allow '"&;|!=()[]{}<>*?#\$
- s/(\s)/\\$1/g; # Re-escape whitespace
- push(@dirs, $_);
}
-push(@dirs, $subdir) unless @dirs;
-$dir = join(' ', @dirs);
+die "$0: invalid rsync-command syntax or options\n" if $in_options;
-if (-f LOGFILE and open LOG,'>>',LOGFILE) {
+@args = ( '.' ) if !@args;
+
+if ($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/ .*//; # Keep only the client's IP addr
$host =~ s/^::ffff://;
$host = gethostbyaddr(inet_aton($host),AF_INET) || $host;
- my $dir_result = $dir eq $orig ? " OK" : "> \"$dir\"";
- printf LOG "%02d:%02d %-13s [%s] =%s\n", $hh, $mm, $host, $command, $dir_result;
+ printf LOG "%02d:%02d %-13s [%s]\n", $hh, $mm, $host, "@opts @args";
close LOG;
}
-exec "$cmd \"$dir\"" or die "exec($cmd \"$dir\") failed: $? $!";
# 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;
+}
Matt McCutchen's Web Site / rsync / rsync.git / blobdiff