[perl #82720] RE: Bug in Net::FTP.pm

# New Ticket Created by  "NEWPORT Dennis" 
# Please include the string:  [perl #82720]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=82720 >


We have found another bug but this time in Net::FTP::dataconn.pm.
Namely:

The problems occurred when connecting to ProFTPD 1.3.3d.

When trying to get a list of files using a pattern that doesn't match
any files the following error occurred:

Can't use an undefined value as a symbol reference at
..../Net/FTP/dataconn.pm line 54.

The problem seems to be that when the NLST command is sent and the
client attempts to open the data connection, the ftp server refuses the
connection. This results in the $ftp variable not being set.

It is not clear if this behaviour is correct or a bug in the FTP server.

The changes that we think work are highlighted in red below. Also I
think you should change the "unique file name" check to also check for
FILE: as per my previous mail. We tried that as well and it works fine.

Thanks.


sub _close
{
my $data = shift;
my $ftp = ${*$data}{'net_ftp_cmd'};

$data->SUPER::close();

return if !defined $ftp;

delete ${*$ftp}{'net_ftp_dataconn'}
if exists ${*$ftp}{'net_ftp_dataconn'} &&
$data == ${*$ftp}{'net_ftp_dataconn'};
}

sub close
{
my $data = shift;
my $ftp = ${*$data}{'net_ftp_cmd'};

if(exists ${*$data}{'net_ftp_bytesread'} && !${*$data}{'net_ftp_eof'}) {
my $junk;
$data->read($junk,1,0);
return $data->abort unless ${*$data}{'net_ftp_eof'};
}

$data->_close;

return if !defined $ftp;

$ftp->response() == CMD_OK &&
$ftp->message =~ /unique file name:\s*(\S*)\s*\)/ &&
(${*$ftp}{'net_ftp_unique'} = $1);
$ftp->status == CMD_OK;
}



---------------------
Dennis Newport

Central Flow Management Unit
Eurocontrol
Raketstraat 96
B-1130 Brussels
Belgium

email:          dennis.newport@eurocontrol.int
<mailto:dennis.newport@eurocontrol.int>
tel:            +32 2 729 9621
fax:            +32 2 729 9703
GSM:    +32 499 943624



________________________________

From: NEWPORT Dennis
Sent: Tuesday 18 January 2011 08:07
To: 'bug-perl@rt.cpan.org'
Subject: Bug in Net::FTP.pm


Background:

OS: RedHat 5, 2.6.18-92.el5
Module: Net::FTP.pm, version 2.78

We used to use wu-ftpd on HP-UX and then migrated to vsftpd on our new
RedHat linux machines. But vsftpd was not good at for some of our
pattern matching and wildcarding requirements on filenames so we have
now upgraded to ProFTPD. This is where the problem has occurred.

We use a Perl script to do some of our ftp'ing. It uses Net::FTP.pm. In
this we call put_unique. The problem is that the wu-ftpd and vsftpd ftp
implementations returned a string that said something like:

<<< 226 Transfer complete (unique file name:TEST_FILE).

where TEST_FILE was the name of the file we were ftp'ing, whereas
ProFTPD returns a sting that says:

<<< 150 FILE: ftpZpQr2p

where ftpZpQr2p is the name given to the unique file. But in this latter
case, this string (ftpZpQr2p) is not returned from put_unique. That is
because in the _store_cmd subroutine there is this line:

if ('STOU' eq uc $cmd and $ftp->message =~ m/unique\ file\
name:(.*)\)|"(.*)"/)

If this is changed to:

if ('STOU' eq uc $cmd and ($ftp->message =~ m/unique\ file\
name:(.*)\)|"(.*)"/ or $ftp->message =~ m/FILE:\ (.*)/))

then put_unique behaves as documented.

I've tested this and it works with wu-ftpd, vsftpd and ProFTPD.

Thanks.


---------------------
Dennis Newport

Central Flow Management Unit
Eurocontrol
Raketstraat 96
B-1130 Brussels
Belgium

email:          dennis.newport@eurocontrol.int
<mailto:dennis.newport@eurocontrol.int>
tel:            +32 2 729 9621
fax:            +32 2 729 9703
GSM:    +32 499 943624



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• [perl #82720] RE: Bug in Net::FTP.pm by NEWPORT Dennis