Net::SFTP permission denied but sftp works

[Anonymous Monk]

I am trying to implement a secure FTP transfer to a remote machine. The remote machine does NOT permit an SSH telnet session, but will allow SFTP sessions. I am able to connect using the command line 'sftp'. However when connecting to the same machine using Net::SFTP I get the following error messages:

local: Connecting to ***********, port 22.
local: Remote protocol version 2.0, remote software version OpenSSH_3.0.2p1
local: Net::SSH::Perl Version 1.23, protocol version 2.0.
local: No compat match: OpenSSH_3.0.2p1.
local: Connection established.
local: Sent key-exchange init (KEXINIT), wait response.
local: Algorithms, c->s: 3des-cbc hmac-sha1 none
local: Algorithms, s->c: 3des-cbc hmac-sha1 none
local: Entering Diffie-Hellman Group 1 key exchange.
local: Sent DH public key, waiting for reply.
local: Received host key, type 'ssh-dss'.
local: Host '****************' is known and matches the host key.
local: Computing shared secret key.
local: Verifying server signature.
local: Waiting for NEWKEYS message.
local: Enabling incoming encryption/MAC/compression.
local: Send NEWKEYS, enable outgoing encryption/MAC/compression.
local: Sending request for user-authentication service.
local: Service accepted: ssh-userauth.
local: Trying empty user-authentication request.
local: Authentication methods that can continue: publickey.
local: Next method to try is publickey.
Permission denied at /opt/perl/lib/site_perl/5.6.1/Net/SFTP.pm line 37

Line 37 of SFTP.pm is:

$ssh->login($param{user}, $param{password});

The remote SFTP host uses public/private keys and only needs a username (ie. user@host) to login - all of which is in my code:

use Net::SFTP;
my %args = (ssh_args => []);
$args{user} = $user;
push @{ $args{ssh_args} }, port => 22;
my $sftp = Net::SFTP->new($host,%args);

Any ideas what the problem might be?

[CombatSquirrel]

First of all, you are not supplying the password for the user, which will give you the local: Trying empty user-authentication request. error message. Secondly, IMHO, ssh_args is a list of named arguments, and therefore a hash. You might want to change

my %args = (ssh_args => [] );
...
push @{ $args{ssh_args} }, port => 22;


to

my %args = (ssh_args => {} );
...
$args{ssh_args}->{port} = 22;


The revised code shold look somewhat like this:

use Net::SFTP;
my %args = (ssh_args => {});
$args{user} = $user;
$args{password} = $pass;
$args{ssh_args}->{port} = 22;
my $sftp = Net::SFTP->new($host,%args);


Everything above is untested, but I think that it'll work for you. Let me know if it does not.

[zengargoyle]

try this, pass in an empty password.

$args{password} = '';

and cross your fingers. you might also want to explicitly specify the path to your identity file. doing these made Net::SSH work for me with keys, never tried SFTP.

[wirrwarr]

Are you sure SFTP means "secure ftp" for the machine you're connecting to? SFTP is also the acronym for "simple ftp" (rfc 913), which is not secure at all.

[ant9000]

Take a deeper look at what happens inside the login() method. Since the module should try to authenticate with a public key, my guess is that the key file is unreadable to the script.

[wadjet]

Thanks everyone. I discovered that perl wasn't reading the keys at all, due to the fact that the SSH config file is located under /opt/ssh/etc on unix (my machine) as opposed to the expected /etc... directory that Net::SFTP looks for. I simply copied the /opt/ssh/etc/ssh_config file to ~/.ssh and uncommented the IdentityFile line with ~/.ssh/id_rsa and all works!

[Anonymous Monk]

Could you please paste your modified code which is working here? even I am facing the same issue

[marto]

No code was changed. This thread is ~20 years old. Perhaps if you have an issue How do I post a question effectively?.