247 lines
7.4 KiB
Bash
Executable File
247 lines
7.4 KiB
Bash
Executable File
#!/usr/bin/perl
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# Name: /usr/local/bin/rrsync (should also have a symlink in /usr/bin)
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# Purpose: Restricts rsync to subdirectory declared in .ssh/authorized_keys
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# Author: Joe Smith <js-cgi@inwap.com> 30-Sep-2004
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# Modified by: Wayne Davison <wayned@samba.org>
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# https://www.guyrutenberg.com/2014/01/14/restricting-ssh-access-to-rsync/
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# insert this before key in authorized keys, include -ro before access root to limit to read only
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# command="/path/to/rrsync /root/of/access" ,no-agent-forwarding,no-port-forwarding,no-pty,no-user-rc,no-X11-forwarding
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use strict;
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use Socket;
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use Cwd 'abs_path';
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use File::Glob ':glob';
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# You may configure these values to your liking. See also the section
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# of options if you want to disable any options that rsync accepts.
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use constant RSYNC => '/usr/bin/rsync';
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use constant LOGFILE => 'rrsync.log';
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my $Usage = <<EOM;
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Use 'command="$0 [-ro|-wo] SUBDIR"'
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in front of lines in $ENV{HOME}/.ssh/authorized_keys
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EOM
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# Handle the -ro and -wo options.
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our $only = '';
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while (@ARGV && $ARGV[0] =~ /^-([rw])o$/) {
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my $r_or_w = $1;
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if ($only && $only ne $r_or_w) {
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die "$0: the -ro and -wo options conflict.\n";
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}
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$only = $r_or_w;
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shift;
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}
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our $subdir = shift;
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die "$0: No subdirectory specified\n$Usage" unless defined $subdir;
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$subdir = abs_path($subdir);
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die "$0: Restricted directory does not exist!\n" if $subdir ne '/' && !-d $subdir;
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# The client uses "rsync -av -e ssh src/ server:dir/", and sshd on the server
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# executes this program when .ssh/authorized_keys has 'command="..."'.
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# For example:
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# command="rrsync logs/client" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAzGhEeNlPr...
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# command="rrsync -ro results" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAmkHG1WCjC...
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#
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# Format of the environment variables set by sshd:
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# SSH_ORIGINAL_COMMAND=rsync --server -vlogDtpr --partial . ARG # push
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# SSH_ORIGINAL_COMMAND=rsync --server --sender -vlogDtpr --partial . ARGS # pull
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# SSH_CONNECTION=client_addr client_port server_port
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my $command = $ENV{SSH_ORIGINAL_COMMAND};
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die "$0: Not invoked via sshd\n$Usage" unless defined $command;
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die "$0: SSH_ORIGINAL_COMMAND='$command' is not rsync\n" unless $command =~ s/^rsync\s+//;
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die "$0: --server option is not first\n" unless $command =~ /^--server\s/;
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our $am_sender = $command =~ /^--server\s+--sender\s/; # Restrictive on purpose!
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die "$0 sending to read-only server not allowed\n" if $only eq 'r' && !$am_sender;
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die "$0 reading from write-only server not allowed\n" if $only eq 'w' && $am_sender;
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### START of options data produced by the cull_options script. ###
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# These options are the only options that rsync might send to the server,
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# and only in the option format that the stock rsync produces.
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# To disable a short-named option, add its letter to this string:
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our $short_disabled = 's';
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our $short_no_arg = 'ACDEHIJKLORSWXbcdgklmnoprstuvxyz'; # DO NOT REMOVE ANY
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our $short_with_num = 'B'; # DO NOT REMOVE ANY
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# To disable a long-named option, change its value to a -1. The values mean:
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# 0 = the option has no arg; 1 = the arg doesn't need any checking; 2 = only
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# check the arg when receiving; and 3 = always check the arg.
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our %long_opt = (
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'append' => 0,
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'backup-dir' => 2,
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'block-size' => 1,
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'bwlimit' => 1,
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'checksum-seed' => 1,
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'compare-dest' => 2,
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'compress-level' => 1,
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'copy-dest' => 2,
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'copy-unsafe-links' => 0,
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'daemon' => -1,
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'debug' => 1,
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'delay-updates' => 0,
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'delete' => 0,
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'delete-after' => 0,
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'delete-before' => 0,
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'delete-delay' => 0,
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'delete-during' => 0,
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'delete-excluded' => 0,
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'delete-missing-args' => 0,
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'existing' => 0,
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'fake-super' => 0,
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'files-from' => 3,
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'force' => 0,
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'from0' => 0,
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'fuzzy' => 0,
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'group' => 0,
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'groupmap' => 1,
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'hard-links' => 0,
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'iconv' => 1,
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'ignore-errors' => 0,
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'ignore-existing' => 0,
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'ignore-missing-args' => 0,
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'ignore-times' => 0,
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'info' => 1,
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'inplace' => 0,
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'link-dest' => 2,
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'links' => 0,
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'list-only' => 0,
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'log-file' => 3,
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'log-format' => 1,
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'max-delete' => 1,
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'max-size' => 1,
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'min-size' => 1,
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'modify-window' => 1,
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'new-compress' => 0,
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'no-implied-dirs' => 0,
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'no-r' => 0,
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'no-relative' => 0,
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'no-specials' => 0,
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'numeric-ids' => 0,
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'one-file-system' => 0,
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'only-write-batch' => 1,
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'owner' => 0,
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'partial' => 0,
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'partial-dir' => 2,
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'perms' => 0,
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'preallocate' => 0,
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'recursive' => 0,
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'remove-sent-files' => $only eq 'r' ? -1 : 0,
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'remove-source-files' => $only eq 'r' ? -1 : 0,
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'safe-links' => 0,
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'sender' => 0,
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'server' => 0,
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'size-only' => 0,
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'skip-compress' => 1,
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'specials' => 0,
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'stats' => 0,
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'suffix' => 1,
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'super' => 0,
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'temp-dir' => 2,
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'timeout' => 1,
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'times' => 0,
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'use-qsort' => 0,
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'usermap' => 1,
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);
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### END of options data produced by the cull_options script. ###
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if ($short_disabled ne '') {
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$short_no_arg =~ s/[$short_disabled]//go;
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$short_with_num =~ s/[$short_disabled]//go;
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}
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$short_no_arg = "[$short_no_arg]" if length($short_no_arg) > 1;
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$short_with_num = "[$short_with_num]" if length($short_with_num) > 1;
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my $write_log = -f LOGFILE && open(LOG, '>>', LOGFILE);
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chdir($subdir) or die "$0: Unable to chdir to restricted dir: $!\n";
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my(@opts, @args);
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my $in_options = 1;
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my $last_opt = '';
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my $check_type;
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while ($command =~ /((?:[^\s\\]+|\\.[^\s\\]*)+)/g) {
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$_ = $1;
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if ($check_type) {
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push(@opts, check_arg($last_opt, $_, $check_type));
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$check_type = 0;
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} elsif ($in_options) {
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push(@opts, $_);
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if ($_ eq '.') {
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$in_options = 0;
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} else {
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die "$0: invalid option: '-'\n" if $_ eq '-';
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next if /^-$short_no_arg*(e\d*\.\w*)?$/o || /^-$short_with_num\d+$/o;
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my($opt,$arg) = /^--([^=]+)(?:=(.*))?$/;
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my $disabled;
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if (defined $opt) {
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my $ct = $long_opt{$opt};
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last unless defined $ct;
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next if $ct == 0;
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if ($ct > 0) {
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if (!defined $arg) {
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$check_type = $ct;
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$last_opt = $opt;
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next;
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}
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$arg = check_arg($opt, $arg, $ct);
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$opts[-1] =~ s/=.*/=$arg/;
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next;
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}
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$disabled = 1;
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$opt = "--$opt";
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} elsif ($short_disabled ne '') {
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$disabled = /^-$short_no_arg*([$short_disabled])/o;
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$opt = "-$1";
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}
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last unless $disabled; # Generate generic failure
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die "$0: option $opt has been disabled on this server.\n";
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}
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} else {
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if ($subdir ne '/') {
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# Validate args to ensure they don't try to leave our restricted dir.
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s{//+}{/}g;
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s{^/}{};
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s{^$}{.};
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die "$0: do not use .. in any path!\n" if m{(^|/)\\?\.\\?\.(\\?/|$)};
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}
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push(@args, bsd_glob($_, GLOB_LIMIT|GLOB_NOCHECK|GLOB_BRACE|GLOB_QUOTE));
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}
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}
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die "$0: invalid rsync-command syntax or options\n" if $in_options;
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@args = ( '.' ) if !@args;
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if ($write_log) {
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my ($mm,$hh) = (localtime)[1,2];
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my $host = $ENV{SSH_CONNECTION} || 'unknown';
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$host =~ s/ .*//; # Keep only the client's IP addr
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$host =~ s/^::ffff://;
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$host = gethostbyaddr(inet_aton($host),AF_INET) || $host;
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printf LOG "%02d:%02d %-13s [%s]\n", $hh, $mm, $host, "@opts @args";
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close LOG;
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}
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# Note: This assumes that the rsync protocol will not be maliciously hijacked.
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exec(RSYNC, @opts, @args) or die "exec(rsync @opts @args) failed: $? $!";
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sub check_arg
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{
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my($opt, $arg, $type) = @_;
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$arg =~ s/\\(.)/$1/g;
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if ($subdir ne '/' && ($type == 3 || ($type == 2 && !$am_sender))) {
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$arg =~ s{//}{/}g;
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die "Do not use .. in --$opt; anchor the path at the root of your restricted dir.\n"
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if $arg =~ m{(^|/)\.\.(/|$)};
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$arg =~ s{^/}{$subdir/};
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}
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$arg;
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}
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