SCP Failure - Error 255

[KarlAustin]

Hi,

Having trouble with SCP. SSH via the bastion works fine.

BASTION_SCP_EXTRA_ARGS="-v" scp -P 2222 -S ~/.bastion/scp_helper1 -i ~/.ssh/id_ed25519 a-local-file [email protected]:/home/username

Results in:

OpenSSH_8.2p1 Ubuntu-4ubuntu0.5, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: Connecting to bastion1.example.org [192.168.99.1] port 22.
debug1: Connection established.
debug1: identity file /home/localuser/.ssh/id_ed25519 type 3
debug1: identity file /home/localuser/.ssh/id_ed25519-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.5
debug1: Remote protocol version 2.0, remote software version OpenSSH_8.9p1
debug1: match: OpenSSH_8.9p1 pat OpenSSH* compat 0x04000000
debug1: Authenticating to bastion1.example.org:22 as 'KarlAustin'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ssh-ed25519
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ssh-ed25519 SHA256:nGDbyi2hY4u2nDQcfvA1JZhLX0a1d8umjx1LhUd0SqA
debug1: Host 'bastion1.example.org' is known and matches the ED25519 host key.
debug1: Found key in /home/localuser/.ssh/known_hosts:85
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey in after 134217728 blocks
debug1: Will attempt key: /home/localuser/.ssh/id_ed25519 ED25519 SHA256:jXXd48b6FgW33arWYxN3ds7PbrY1flRJX+Aaph+7iQL explicit
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,[email protected],ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected]>
debug1: kex_input_ext_info: [email protected] (unrecognised)
debug1: SSH2_MSG_SERVICE_ACCEPT received
*------------------------------------------------------------------------------*
|THIS IS A PRIVATE COMPUTER SYSTEM, UNAUTHORIZED ACCESS IS STRICTLY PROHIBITED.|
|ALL CONNECTIONS ARE LOGGED. IF YOU ARE NOT AUTHORIZED, DISCONNECT NOW.        |
*------------------------------------------------------------------------------*
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/localuser/.ssh/id_ed25519 ED25519 SHA256:jXXd48b6FgW33arWYxN3ds7PbrY1flRJX+Aaph+7iQL explicit
debug1: Server accepts key: /home/localuser/.ssh/id_ed25519 ED25519 SHA256:jXXd48b6FgW33arWYxN3ds7PbrY1flRJX+Aaph+7iQL explicit
Enter passphrase for key '/home/localuser/.ssh/id_ed25519':
debug1: Authentication succeeded (publickey).
Authenticated to bastion1.example.org ([192.168.99.1]:22).
debug1: channel 0: new [client-session]
debug1: Requesting [email protected]
debug1: Entering interactive session.
debug1: pledge: network
debug1: client_input_global_request: rtype [email protected] want_reply 0
debug1: Remote: /home/bastionUser/.ssh/authorized_keys2:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
debug1: Remote: /home/bastionUser/.ssh/authorized_keys2:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
debug1: Sending environment.
debug1: Sending env LANG = C.UTF-8
debug1: Sending command: --user username --port 2222 --host 172.168.99.1 --osh scp --scp-cmd scp#-t#/home/username
>>> Hello bastionUser, transferring your file through the bastion to [email protected]:2222...
[email protected]: Permission denied (publickey).

Error launching transfer: Command exited with status 255
lost connection
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug1: client_input_channel_req: channel 0 rtype [email protected] reply 0
debug1: channel 0: free: client-session, nchannels 1
debug1: fd 0 clearing O_NONBLOCK
Transferred: sent 2348, received 3308 bytes, in 0.8 seconds
Bytes per second: sent 2940.8, received 4143.2
debug1: Exit status 100

I can see by enabling debug logging in sshd on the server I am scp'ing to that the key is accepted:

Accepted key ED25519 SHA256:<hash> found at /home/username/.ssh/authorized_keys:1

I then see:

Postponed publickey for username from <bastion-ip> port 54364 ssh2 [preauth]
Connection closed by authenticating user username <bastion-ip> port 54364 [preauth]

What I never see is a prompt to decrypt the group ssh key for the group this server is in. So I'm guessing that's where the issue lies?

Is there a way to fix this?