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Re^3: Help Required - Problem Automating SFTP

by salva (Canon)
on Jan 28, 2009 at 13:03 UTC ( #739537=note: print w/replies, xml ) Need Help??


in reply to Re^2: Help Required - Problem Automating SFTP
in thread Help Required - Problem Automating SFTP

does command line scp work?

Run a couple of tests using scp and sftp commands with the verbose flag (-v) and post here the output.

Replies are listed 'Best First'.
Re^4: Help Required - Problem Automating SFTP
by Kraythorne (Sexton) on Jan 28, 2009 at 16:18 UTC
    VERBOSE OUTPUT FROM SFTP

    Connecting to *Host_IP*...
    debug1: Reading configuration data /etc/ssh_config
    debug2: ssh_connect: needpriv 0
    debug1: Connecting to *Host_IP* *Host_IP* port *Port*.
    debug1: Connection established.
    debug3: Not a RSA1 key file C:\\id_cmf_mediatech.
    debug2: key_type_from_name: unknown key type '-----BEGIN'
    debug3: key_read: missing keytype
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug3: key_read: missing whitespace
    debug2: key_type_from_name: unknown key type '-----END'
    debug3: key_read: missing keytype
    debug1: identity file C:\\id_cmf_mediatech type -1
    debug1: Remote protocol version 2.0, remote software version OpenSSH_5.1
    debug1: match: OpenSSH_5.1 pat OpenSSH*
    debug1: Enabling compatibility mode for protocol 2.0
    debug1: Local version string SSH-2.0-OpenSSH_3.8.1p1
    debug1: SSH2_MSG_KEXINIT sent
    debug1: SSH2_MSG_KEXINIT received
    debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
    debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
    debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
    debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
    debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
    debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
    debug2: kex_parse_kexinit: none,zlib
    debug2: kex_parse_kexinit: none,zlib
    debug2: kex_parse_kexinit:
    debug2: kex_parse_kexinit:
    debug2: kex_parse_kexinit: first_kex_follows 0
    debug2: kex_parse_kexinit: reserved 0
    debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
    debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
    debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
    debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
    debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
    debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
    debug2: kex_parse_kexinit: none,zlib@openssh.com
    debug2: kex_parse_kexinit: none,zlib@openssh.com
    debug2: kex_parse_kexinit:
    debug2: kex_parse_kexinit:
    debug2: kex_parse_kexinit: first_kex_follows 0
    debug2: kex_parse_kexinit: reserved 0
    debug2: mac_init: found hmac-md5
    debug1: kex: server->client aes128-cbc hmac-md5 none
    debug2: mac_init: found hmac-md5
    debug1: kex: client->server aes128-cbc hmac-md5 none
    debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
    debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
    debug2: dh_gen_key: priv key bits set: 122/256
    debug2: bits set: 517/1024
    debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
    debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
    debug3: check_host_in_hostfile: filename /home/.ssh/known_hosts
    debug3: check_host_in_hostfile: match line 1
    debug1: Host '*Host_IP*' is known and matches the RSA host key.
    debug1: Found key in /home/.ssh/known_hosts:1
    debug2: bits set: 520/1024
    debug1: ssh_rsa_verify: signature correct
    debug2: kex_derive_keys
    debug2: set_newkeys: mode 1
    debug1: SSH2_MSG_NEWKEYS sent
    debug1: expecting SSH2_MSG_NEWKEYS
    debug2: set_newkeys: mode 0
    debug1: SSH2_MSG_NEWKEYS received
    debug1: SSH2_MSG_SERVICE_REQUEST sent
    debug2: service_accept: ssh-userauth
    debug1: SSH2_MSG_SERVICE_ACCEPT received
    debug2: key: C:\\id_cmf_mediatech (0x0)
    debug1: Authentications that can continue: publickey,gssapi-with-mic,password
    debug3: start over, passed a different list publickey,gssapi-with-mic,password
    debug3: preferred publickey,keyboard-interactive,password
    debug3: authmethod_lookup publickey
    debug3: remaining preferred: keyboard-interactive,password
    debug3: authmethod_is_enabled publickey
    debug1: Next authentication method: publickey
    debug1: Trying private key: C:\\id_cmf_mediatech
    debug1: read PEM private key done: type RSA
    debug3: sign_and_send_pubkey
    debug2: we sent a publickey packet, wait for reply
    debug1: Authentication succeeded (publickey).
    debug2: fd 4 setting O_NONBLOCK
    debug2: fd 5 setting O_NONBLOCK
    debug1: channel 0: new client-session
    debug3: ssh_session2_open: channel_new: 0
    debug2: channel 0: send open
    debug1: Entering interactive session.
    debug2: callback start
    debug2: ssh_session2_setup: id 0
    debug1: Sending subsystem: sftp-server
    debug2: channel 0: request subsystem
    debug2: callback done
    debug2: channel 0: open confirm rwindow 0 rmax 32768
    Request for subsystem 'sftp-server' failed on channel 0
    Connection closed


    If I don't put in the '-s sftp-server' switch the debug ends:


    debug1: Entering interactive session.
    debug2: callback start
    debug2: ssh_session2_setup: id 0
    debug1: Sending subsystem: sftp
    debug2: channel 0: request subsystem
    debug2: callback done
    debug2: channel 0: open confirm rwindow 0 rmax 32768
    Request for subsystem 'sftp' failed on channel 0
    Connection closed

    Any Thoughts?
      scp generates:

      exec: cp: Not Found

      Is that cos I'm using windows - searching the web makes it look like these are unix commands that I don't have installed?
        both scp and sftp should be part of the OpenSSH package. PuTTY has pscp and psftp.
      Ok, the saga continues...

      This is the information I have back from the client:

      'We restrict external logins to sftp connections only and chroot the users into their home directories, i.e. you don’t see “/home/mediatech” when you log in, you just see “/”. Now the problem arises when you are chrooted, in this case the command line sftp won’t connect, when you are not chrooted command line sftp works fine. Unfortunately this server is shared with other external customers so it is considered good practice to have all accounts chrooted.

      I can’t find anything about why this is the case or how to fix it but I have found that psftp (command line sftp that comes with Putty) works. As far as I can see psftp is a generic command line sftp client that does everything Openssh sftp does. I assume that it would integrate into Perl scripts exactly the same as sftp would.'

      So my question is - Can I get Net::SFTP::Foreign to work with Putty psftp? If not is there another module I could use?

      Thanks
        I see, probably what is happening is that they are expecting you to use the old SSH version 1 approach for launching the SFTP server on the remote side.

        Just to test that this is the case, what happens if you run these commands...?

        plink *remoteHost* -p *remotePort* -v sftp-server plink *remoteHost* -p *remotePort* -v /usr/lib/sftp-server
        Does anyone of them hangs (that means that the sftp-server is listening) instead of exiting with an error?

        Once you find how to launch the remote sftp-server, tell Net::SFTP::Foreign to use the same command with the open2_cmd constructor option. For instance:

        my $sftp = Net::SFTP::Foreign->new(open2_cmd => "plink $host -p $port +/usr/lib/sftp-server"); $sftp->error and die "SFTP connection failed: " . $sftp->error;

        update: and BTW, I think the root of the problem is an incomplete chroot'ed configuration for sshd in the remote side. Probably, they have not configured sshd to use internal-sftp server for the SFTP subsystem. Ask them to check that the sshd_config file contains the following line:

        Subsystem sftp internal-sftp
        (a how-to: http://www.debian-administration.org/articles/590)
        I can get 'plink' to connect and hang up to this point:

        Offered public key
        Offer of public key accepted
        Authenticating with public key "rsa-key-20081029"
        Access granted
        Opened channel for session
        Allocated pty (ospeed 38400bps, ispeed 38400bps
        Started a shell/command

        ..and when I break out of it I get:

        Sent EOF message
        ^C

        So it looks like that works

        However, when I put the same syntax into Net::SFTP::Foreign, after the shell starts, I get:

        Server exited on signal "INT"
        Disconnected: All channels closed

        Are we getting closer?
        Command Line 'Plink':

        C:\Program Files\PuTTY>plink *mycompany@host* -P *port* -v -i c:/id_cmf_mediatech.ppk sftp-server
        Looking up host "*host_IP*"
        Connecting to *host_IP* port *port*
        Server version: SSH-2.0-OpenSSH_5.1
        We claim version: SSH-2.0-PuTTY_Release_0.60
        Using SSH protocol version 2
        Doing Diffie-Hellman group exchange
        Doing Diffie-Hellman key exchange with hash SHA-256
        Host key fingerprint is:
        ssh-rsa 2048 *FINGERPRINT*
        Initialised AES-256 SDCTR client->server encryption
        Initialised HMAC-SHA1 client->server MAC algorithm
        Initialised AES-256 SDCTR server->client encryption
        Initialised HMAC-SHA1 server->client MAC algorithm
        Reading private key file "c:/id_cmf_mediatech.ppk"
        Using username "mediatech".
        Offered public key
        Offer of public key accepted
        Authenticating with public key "rsa-key-20081029"
        Access granted
        Opened channel for session
        Started a shell/command

        *HANGS HERE UNTIL I BREAK*

        Sent EOF message
        ^C


        Net::SFTP::Foreign code:

        #228 ssh cmd: "c:/program files/putty/plink" *mycompany*@*host* -P *port* -v -i c:\id_cmf_mediatech.ppk sftp-server
        #228 queueing msg len: 5, code:1, id:3 ... 1 00 00 00 05 01 00 00 00 03 | .........
        #228 waiting for message... 1
        Looking up host "*host_IP*"
        Connecting to *host_IP* port *port*
        Server version: SSH-2.0-OpenSSH_5.1
        We claim version: SSH-2.0-PuTTY_Release_0.60
        Using SSH protocol version 2
        Doing Diffie-Hellman group exchange
        Doing Diffie-Hellman key exchange with hash SHA-256
        Host key fingerprint is:
        ssh-rsa 2048 *fingerprint*
        Initialised AES-256 SDCTR client->server encryption
        Initialised HMAC-SHA1 client->server MAC algorithm
        Initialised AES-256 SDCTR server->client encryption
        Initialised HMAC-SHA1 server->client MAC algorithm
        Reading private key file "c:\id_cmf_mediatech.ppk"
        Using username "mediatech".
        Offered public key
        Offer of public key accepted
        Authenticating with public key "rsa-key-20081029"
        Access granted
        Opened channel for session
        Started a shell/command
        #228 got it!, len:95, code:2, id:3, status: - 02 00 00 00 03 00 00 00 18 70 6f 73 69 78 2d 72 65 6e 61 6d 65 40 6f 70 65 6e 73 73 68 2e 63 6f | .........posix-rename@openssh.co 6d 00 00 00 01 31 00 00 00 13 73 74 61 74 76 66 73 40 6f 70 65 6e 73 73 68 2e 63 6f 6d 00 00 00 | m....1....statvfs@openssh.com... 01 32 00 00 00 14 66 73 74 61 74 76 66 73 40 6f 70 65 6e 73 73 68 2e 63 6f 6d 00 00 00 01 32 | .2....fstatvfs@openssh.com....2
        #228 Net::SFTP::Foreign=HASH(0x226e20)->DESTROY called (current pid: 228, discon nect_by_pid: )
        #228 Net::SFTP::Foreign=HASH(0x226e20)->disconnect called (ssh pid: 3028)
        #228 _conn_lost
        #228 _set_status code: 7, str: Connection lost
        #228 _set_err code: 37, str: Connection to remote server is broken
        Version 1.46

        Yep, just calling the constructor at the mo, I need to get into how the module works a bit more now I know it's working!

        ...a nice bit of code. Thanks!!

        By the way, is there a 'move' method in Net::SFTP::Foreign module so that you can move files from one directory on the FTP site to another?
      That means that SFTP has been forbidden in the remote host configuration.

      But as you have said that FileZilla works, maybe they are allowing scp, so just try it!

      Using Putty pscp:

      *Host_IP*:c:/test.txt
      Looking up host "*host_IP*"
      Connecting to *host_IP port *port*
      Server version: SSH-2.0-OpenSSH_5.1
      We claim version: SSH-2.0-PuTTY_Release_0.60
      Using SSH protocol version 2
      Doing Diffie-Hellman group exchange
      Doing Diffie-Hellman key exchange with hash SHA-256
      Host key fingerprint is:
      ssh-rsa 2048 *fingerprint*
      Initialised AES-256 SDCTR client->server encryption
      Initialised HMAC-SHA1 client->server MAC algorithm
      Initialised AES-256 SDCTR server->client encryption
      Initialised HMAC-SHA1 server->client MAC algorithm
      Reading private key file "c:/id_cmf_mediatech.ppk"
      Using username "*mycompany*".
      Offered public key
      Offer of public key accepted
      Authenticating with public key "rsa-key-20081029"
      Access granted
      Opened channel for session
      Primary command failed; attempting fallback
      Started a shell/command
      Using SCP1
      Connected to *host_IP*

      Ok, this looks like it can get me a connection - how can I use this with Net::SFTP::Foreign to automate file downloads and moving files on the clients FTP site?
        Net::SFTP::Foreign requires SFTP to be working (or allowed) on the remote server.

        If all you are allowed to do is to scp there, then you can try Net::SSH2, Net::SSH::Perl or Net::SCP, though, as you are using keys for authentication, probably just calling the scp (or pscp) program from Perl would be the simplest solution.

        Also, take into account that scp is very limiting and will allow you to transfer files from one side to the other only. For instance, you will not be able to move files around on the server (update: oh, well, unless they allow you to run any remote command and not just scp in client mode).

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