1#!/usr/bin/perl 2# Name: /usr/local/bin/rrsync (should also have a symlink in /usr/bin) 3# Purpose: Restricts rsync to subdirectory declared in .ssh/authorized_keys 4# Author: Joe Smith <js-cgi@inwap.com> 30-Sep-2004 5# Modified by: Wayne Davison <wayned@samba.org> 6use strict; 7 8use Socket; 9use Cwd 'abs_path'; 10use File::Glob ':glob'; 11 12# You may configure these values to your liking. See also the section 13# of options if you want to disable any options that rsync accepts. 14use constant RSYNC => '/usr/bin/rsync'; 15use constant LOGFILE => 'rrsync.log'; 16 17my $Usage = <<EOM; 18Use 'command="$0 [-ro] SUBDIR"' 19 in front of lines in $ENV{HOME}/.ssh/authorized_keys 20EOM 21 22our $ro = (@ARGV && $ARGV[0] eq '-ro') ? shift : ''; # -ro = Read-Only 23our $subdir = shift; 24die "$0: No subdirectory specified\n$Usage" unless defined $subdir; 25$subdir = abs_path($subdir); 26die "$0: Restricted directory does not exist!\n" if $subdir ne '/' && !-d $subdir; 27 28# The client uses "rsync -av -e ssh src/ server:dir/", and sshd on the server 29# executes this program when .ssh/authorized_keys has 'command="..."'. 30# For example: 31# command="rrsync logs/client" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAzGhEeNlPr... 32# command="rrsync -ro results" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAmkHG1WCjC... 33# 34# Format of the envrionment variables set by sshd: 35# SSH_ORIGINAL_COMMAND=rsync --server -vlogDtpr --partial . ARG # push 36# SSH_ORIGINAL_COMMAND=rsync --server --sender -vlogDtpr --partial . ARGS # pull 37# SSH_CONNECTION=client_addr client_port server_port 38 39my $command = $ENV{SSH_ORIGINAL_COMMAND}; 40die "$0: Not invoked via sshd\n$Usage" unless defined $command; 41die "$0: SSH_ORIGINAL_COMMAND='$command' is not rsync\n" unless $command =~ s/^rsync\s+//; 42our $am_sender = $command =~ /^--server\s+--sender\s/; # Restrictive on purpose! 43die "$0 -ro: sending to read-only server not allowed\n" if $ro && !$am_sender; 44 45### START of options data produced by the cull_options script. ### 46 47# These options are the only options that rsync might send to the server, 48# and only in the option format that the stock rsync produces. 49 50# To disable a short-named option, add its letter to this string: 51our $short_disabled = ''; 52 53our $short_no_arg = 'CDEHIKLORSWbcdgklmnoprtuvxz'; # DO NOT REMOVE ANY 54our $short_with_num = 'B'; # DO NOT REMOVE ANY 55 56# To disable a long-named option, change its value to a -1. The values mean: 57# 0 = the option has no arg; 1 = the arg doesn't need any checking; 2 = only 58# check the arg when receiving; and 3 = always check the arg. 59our %long_opt = ( 60 'append' => 0, 61 'backup-dir' => 2, 62 'bwlimit' => 1, 63 'checksum-seed' => 1, 64 'compare-dest' => 2, 65 'compress-level' => 1, 66 'copy-dest' => 2, 67 'copy-unsafe-links' => 0, 68 'daemon' => 0, 69 'delay-updates' => 0, 70 'delete' => 0, 71 'delete-after' => 0, 72 'delete-before' => 0, 73 'delete-during' => 0, 74 'delete-excluded' => 0, 75 'existing' => 0, 76 'files-from' => 3, 77 'force' => 0, 78 'from0' => 0, 79 'fuzzy' => 0, 80 'ignore-errors' => 0, 81 'ignore-existing' => 0, 82 'inplace' => 0, 83 'link-dest' => 2, 84 'list-only' => 0, 85 'log-format' => 1, 86 'max-delete' => 1, 87 'max-size' => 1, 88 'min-size' => 1, 89 'modify-window' => 1, 90 'no-implied-dirs' => 0, 91 'no-r' => 0, 92 'no-relative' => 0, 93 'no-specials' => 0, 94 'numeric-ids' => 0, 95 'only-write-batch' => 1, 96 'partial' => 0, 97 'partial-dir' => 2, 98 'remove-sent-files' => $ro ? -1 : 0, 99 'remove-source-files' => $ro ? -1 : 0, 100 'safe-links' => 0, 101 'sender' => 0, 102 'server' => 0, 103 'size-only' => 0, 104 'specials' => 0, 105 'suffix' => 1, 106 'super' => 0, 107 'temp-dir' => 2, 108 'timeout' => 1, 109); 110 111### END of options data produced by the cull_options script. ### 112 113if ($short_disabled ne '') { 114 $short_no_arg =~ s/[$short_disabled]//go; 115 $short_with_num =~ s/[$short_disabled]//go; 116} 117$short_no_arg = "[$short_no_arg]" if length($short_no_arg) > 1; 118$short_with_num = "[$short_with_num]" if length($short_with_num) > 1; 119 120my $write_log = -f LOGFILE && open(LOG, '>>', LOGFILE); 121 122chdir($subdir) or die "$0: Unable to chdir to restricted dir: $!\n"; 123 124my(@opts, @args); 125my $in_options = 1; 126my $last_opt = ''; 127my $check_type; 128while ($command =~ /((?:[^\s\\]+|\\.[^\s\\]*)+)/g) { 129 $_ = $1; 130 if ($check_type) { 131 push(@opts, check_arg($last_opt, $_, $check_type)); 132 $check_type = 0; 133 } elsif ($in_options) { 134 push(@opts, $_); 135 if ($_ eq '.') { 136 $in_options = 0; 137 } else { 138 next if /^-$short_no_arg+$/o || /^-$short_with_num\d+$/o; 139 140 my($opt,$arg) = /^--([^=]+)(?:=(.*))?$/; 141 my $disabled; 142 if (defined $opt) { 143 my $ct = $long_opt{$opt}; 144 last unless defined $ct; 145 next if $ct == 0; 146 if ($ct > 0) { 147 if (!defined $arg) { 148 $check_type = $ct; 149 $last_opt = $opt; 150 next; 151 } 152 $arg = check_arg($opt, $arg, $ct); 153 $opts[-1] =~ s/=.*/=$arg/; 154 next; 155 } 156 $disabled = 1; 157 $opt = "--$opt"; 158 } elsif ($short_disabled ne '') { 159 $disabled = /^-$short_no_arg*([$short_disabled])/o; 160 $opt = "-$1"; 161 } 162 163 last unless $disabled; # Generate generic failure 164 die "$0: option $opt has been disabled on this server.\n"; 165 } 166 } else { 167 if ($subdir ne '/') { 168 # Validate args to ensure they don't try to leave our restricted dir. 169 s#//+#/#g; 170 s#^/##; 171 s#^$#.#; 172 die "Do not use .. in any path!\n" if m#(^|/)\\?\.\\?\.(\\?/|$)#; 173 } 174 push(@args, bsd_glob($_, GLOB_LIMIT|GLOB_NOCHECK|GLOB_BRACE|GLOB_QUOTE)); 175 } 176} 177die "$0: invalid rsync-command syntax or options\n" if $in_options; 178 179@args = ( '.' ) if !@args; 180 181if ($write_log) { 182 my ($mm,$hh) = (localtime)[1,2]; 183 my $host = $ENV{SSH_CONNECTION} || 'unknown'; 184 $host =~ s/ .*//; # Keep only the client's IP addr 185 $host =~ s/^::ffff://; 186 $host = gethostbyaddr(inet_aton($host),AF_INET) || $host; 187 printf LOG "%02d:%02d %-13s [%s]\n", $hh, $mm, $host, "@opts @args"; 188 close LOG; 189} 190 191# Note: This assumes that the rsync protocol will not be maliciously hijacked. 192exec(RSYNC, @opts, @args) or die "exec(rsync @opts @args) failed: $? $!"; 193 194sub check_arg 195{ 196 my($opt, $arg, $type) = @_; 197 $arg =~ s/\\(.)/$1/g; 198 if ($subdir ne '/' && ($type == 3 || ($type == 2 && !$am_sender))) { 199 $arg =~ s#//#/#g; 200 die "Do not use .. in --$opt; anchor the path at the root of your restricted dir.\n" 201 if $arg =~ m#(^|/)\.\.(/|$)#; 202 $arg =~ s#^/#$subdir/#; 203 } 204 $arg; 205} 206