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This queue is for tickets about the Net-FTPServer CPAN distribution.

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The Basics
Id: 29530
Status: open
Priority: 0/
Queue: Net-FTPServer

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Owner: Nobody in particular
Requestors: BRONG [...] cpan.org
Cc:
AdminCc:

Bug Information
Severity: Wishlist
Broken in: 1.122
Fixed in: (no value)



Subject: [PATCH] Support RFC 4217 "AUTH TLS" encryption if IO::Socket::SSL is present
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This patch makes Net::FTPServer support "AUTH TLS" and switch to an encrypted session. In theory it also supports CCC (switching back from TLS) with IO::Socket::SSL version 1.09 (needs the stop_SSL function) but I haven't tested that. This patch is running in production on the FastMail.FM FTP server and once I removed explicit SSL version requirements it seems to be working fine for all our customers.
Subject: ssl.diff
Download ssl.diff
text/x-diff 8.3k
Index: Net/FTPServer.pm =================================================================== --- Net.orig/FTPServer.pm 2007-09-12 22:43:28.000000000 -0400 +++ Net/FTPServer.pm 2007-09-21 00:07:57.000000000 -0400 @@ -54,6 +54,7 @@ * Directory aliases and CDPATH support. * Extensible command set. * Generate archives on the fly. + * SSL/TLS security =head1 INSTALLING AND RUNNING THE SERVER @@ -862,6 +863,30 @@ Example: C<enable syslog: 0> +=item enable ssl + +Enable ssl/tls encryption. Requires IO::Socket::SSL to be +installed. Turning this on will cause AUTH TLS to be +advertised via FEAT. + +This SSL mode is compatible with RFC4217 clients, where it +is often called "Explicit FTPS". You will need to give an +SSL certificate and key pair. + +Default: 0 + +Example: C<enable ssl: 1> + +=item ssl cert file +=item ssl key file + +Paths to the key and certificate files for SSL. + +There is no default. + +Example: C<ssl cert file: /etc/ssl/server.crt> +Example: C<ssl key file: /etc/ssl/server.key> + =item ident timeout Timeout for ident authentication lookups. @@ -2178,6 +2203,7 @@ eval "use BSD::Resource;"; eval "use Digest::MD5;"; eval "use File::Sync;"; +eval "use IO::Socket::SSL"; # Global variables and constants. use vars qw(@_default_commands @@ -2209,6 +2235,8 @@ "CLNT", # Experimental IP-less virtual hosting. "HOST", + # RFC4217 TLS AUTH (subset of RFC 2228) + "AUTH", "PBSZ", "PROT", "CCC", ); @_default_site_commands @@ -2315,6 +2343,15 @@ $self->post_configuration_hook; + # include TLS features if SSL support available + if ($self->config("enable ssl")) + { + $self->{features}{AUTH} = 'TLS'; + $self->{features}{PBSZ} = undef; + $self->{features}{PROT} = undef; + $self->{features}{CCC} = undef; + } + # Initialize Max Clients Settings $self->{_max_clients} = $self->config ("max clients") || 255; @@ -2853,7 +2890,9 @@ { %no_authentication_commands = ("USER" => 1, "PASS" => 1, "LANG" => 1, "FEAT" => 1, - "HELP" => 1, "QUIT" => 1, "HOST" => 1); + "HELP" => 1, "QUIT" => 1, "HOST" => 1, + "AUTH" => 1, "PBSZ" => 1, "PROT" => 1, "CCC" => 1, + ); } # Start reading commands from the client. @@ -2870,7 +2909,7 @@ # XXX This does not comply properly with RFC 2640 section 3.1 - # We should translate <CR><NUL> to <CR> and treat ONLY <CR><LF> # as a line ending character. - last unless defined ($_ = <STDIN>); + last unless defined ($_ = $self->{_sock}->getline()); $self->_check_signals; @@ -3592,6 +3631,7 @@ # Duplicate the socket so it looks like we were called # from inetd. + $self->{_sock} = $sock; dup2 ($sock->fileno, 0); dup2 ($sock->fileno, 1); @@ -3958,15 +3998,15 @@ if (@_ == 1) # Single-line response. { - print $code, " ", $_[0], "\r\n"; + $self->{_sock}->print($code, " ", $_[0], "\r\n"); } else # Multi-line response. { for (my $i = 0; $i < @_-1; ++$i) { - print $code, "-", $_[$i], "\r\n"; + $self->{_sock}->print($code, "-", $_[$i], "\r\n"); } - print $code, " ", $_[@_-1], "\r\n"; + $self->{_sock}->print($code, " ", $_[@_-1], "\r\n"); } $self->log ("info", "reply: $code") if $self->{debug}; @@ -4387,6 +4427,140 @@ $self->reply (200, "HOST set to $self->{sitename}."); } +sub _AUTH_command + { + my $self = shift; + my $cmd = shift; + my $rest = shift; + + my $ucr = uc($rest); + + # If the user issues this command when logged in, generate an error. + # We have to do this basically because of chroot and setuid stuff we + # can't ``relogin'' as a different user. + if ($self->{authenticated}) + { + $self->reply (503, "You are already logged in."); + return; + } + + if ($self->{user}) + { + $self->reply (503, "You have already sent a USER command, too late to switch now."); + return; + } + + if ($ucr ne 'TLS' and $ucr ne 'SSL') + { + $self->reply (504, "Mechanism not known here."); + } + + if (not $self->config("enable ssl")) + { + $self->reply (534, "SSL is not enabled on this server."); + } + + if (not exists $INC{"IO/Socket/SSL.pm"}) + { + $self->reply (431, "IO::Socket::SSL is not installed, unable to encrypt."); + } + + # Accept the TLS session. + $self->reply (234, "AUTH=$ucr"); + my $cert = $self->config("ssl cert file") || $self->config("ssl certificate file"); + my $key = $self->config("ssl key file"); + if (IO::Socket::SSL->start_SSL($self->{_sock}, + SSL_server => 1, + SSL_cert_file => $cert, + SSL_key_file => $key, + )) + { + $self->{tls_control} = 1; + $self->{tls_type} = $ucr; + } + else + { + # failed, what can we do? + die "Failed to start TLS " . IO::Socket::SSL::errstr(); + } + } + +sub _PBSZ_command + { + my $self = shift; + my $cmd = shift; + my $rest = shift; + + if (!$self->{tls_control}) + { + $self->reply (503, "Control connection is not protected"); + return; + } + + if ($rest != 0) + { + $self->reply (501, "Size must be 0 for TLS"); + return; + } + + $self->{pbsz_provided} = 1; + $self->reply (200, "PBSZ=0"); + } + +sub _PROT_command + { + my $self = shift; + my $cmd = shift; + my $rest = shift; + + my $ucr = uc($rest); + + if (!$self->{tls_control}) + { + $self->reply (503, "Control connection is not protected"); + return; + } + + if (!$self->{pbsz_provided}) + { + $self->reply (503, "Pointless block size command has not been issued"); + return; + } + + if ($ucr ne 'C' and $ucr ne 'P') + { + $self->reply (536, "TLS only supports P and C"); + return; + } + + $self->{tls_data} = ($ucr eq 'P'); + $self->reply (200, "PROT=$ucr"); + } + +sub _CCC_command + { + my $self = shift; + my $cmd = shift; + my $rest = shift; + + if (!$self->{tls_control}) + { + $self->reply (503, "Control connection is not protected"); + return; + } + + if ($self->{_sock}->can('stop_SSL')) + { + $self->reply (200, "CCC"); + $self->{_sock}->stop_SSL(); + $self->{tls_control} = 0; + } + else + { + $self->reply(534, "Unable to shut down TLS on this connection"); + } + } + sub _USER_command { my $self = shift; @@ -6554,21 +6728,21 @@ # wu-ftpd by putting the server code in each line). # # See RFC 2389 section 3.2. - print "211-Extensions supported:\r\n"; + $self->{_sock}->print("211-Extensions supported:\r\n"); foreach (sort keys %{$self->{features}}) { unless ($self->{features}{$_}) { - print " $_\r\n"; + $self->{_sock}->print(" $_\r\n"); } else { - print " $_ ", $self->{features}{$_}, "\r\n"; + $self->{_sock}->print(" $_ ", $self->{features}{$_}, "\r\n"); } } - print "211 END\r\n"; + $self->{_sock}->print("211 END\r\n"); } sub _OPTS_command @@ -6772,9 +6946,9 @@ my $info = $self->_mlst_format ($filename, $fileh, $dirh); # Can't use $self->reply since it produces the wrong format. - print "250-Listing of $filename:\r\n"; - print " ", $info, "\r\n"; - print "250 End of listing.\r\n"; + $self->{_sock}->print("250-Listing of $filename:\r\n"); + $self->{_sock}->print(" ", $info, "\r\n"); + $self->{_sock}->print("250 End of listing.\r\n"); } sub _MLSD_command @@ -7463,6 +7637,26 @@ or warn "setsockopt: SO_RCVBUF: $!"; } + # Data connections are PROTected, enable SSL + if ($self->{tls_data}) + { + my $cert = $self->config("ssl cert file") || $self->config("ssl certificate file"); + my $key = $self->config("ssl key file"); + if (IO::Socket::SSL->start_SSL($sock, + SSL_server => 1, + SSL_cert_file => $cert, + SSL_key_file => $key, + )) + { + # yay, all good + } + else + { + # failed, what can we do? + die "Failed to start TLS connection"; # woot + } + } + return $sock; } @@ -8286,10 +8480,12 @@ RFC 765, RFC 959, RFC 1579, +RFC 2228, RFC 2389, RFC 2428, RFC 2577, RFC 2640, +RFC 4217, Extensions to FTP Internet Draft draft-ietf-ftpext-mlst-NN.txt. =cut
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On 2007-09-21 00:14:29, BRONG wrote : Show quoted text
> This patch makes Net::FTPServer support "AUTH TLS" and switch > to an encrypted session. > > In theory it also supports CCC (switching back from TLS) with > IO::Socket::SSL version 1.09 (needs the stop_SSL function) but > I haven't tested that. > > This patch is running in production on the FastMail.FM FTP server > and once I removed explicit SSL version requirements it seems to > be working fine for all our customers.
FWIW, I am now using this patch as well. I added a fix to make the tests pass, as well as RT #29529, and published the code here: » https://github.com/maddingue/p5-net-ftpserver -- Close the world, txEn eht nepO.


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