[Error] Load key [...] invalid format

[antonionardella]

Hello here!

Today I have an issue using the Ledger Nano to log in using the ledger-agent. It worked without issues until 3-4 days ago.

2022-02-28 10:13:01,816 WARNING      error: 27                                                                                            [server.py:100]
Traceback (most recent call last):
  File "/home/[REDACTED]/.local/lib/python3.10/site-packages/libagent/server.py", line 95, in handle_connection
    reply = handler.handle(msg=msg)
  File "/home/[REDACTED]/.local/lib/python3.10/site-packages/libagent/ssh/protocol.py", line 98, in handle
    log.warning('Unsupported command: %s (%d)', msg_name(code), code)
  File "/home/[REDACTED]/.local/lib/python3.10/site-packages/libagent/ssh/protocol.py", line 54, in msg_name
    return ids[code]
KeyError: 27
Load key "/tmp/trezor-ssh-pubkey-5pcf4wio": invalid format
[REDACTED]@[REDACTED]'s password

Any ideas what I could look at?

Thanks

[mavaa]

Having the same problem. I'm not 100% sure, but I think this is related to this feature in openssh 8.9(?)
https://www.openssh.com/agent-restrict.html

Temporary workaround for me was to downgrade to openssh 8.8

[mavaa]

The code "27" from openssh is called "SSH_AGENTC_EXTENSION" which seem to be documented here: https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.agent

I assume this has te be hadled somehow in libagent/ssh/protocol.py->handle, but I have no idea how that should be done.

[antonionardella]

I can confirm that downgrading openssh to 8.8 also worked on my Manjaro system.

[onlykey]

@romanz It looks like this issue was introduced with 'OpenSSH_8.9p1, OpenSSL 1.1.1m 14 Dec 2021'

Currently, this affects Arch and Manjaro Linux distributions as they have the latest OpenSSH version. Debian based Linux is not affected yet as it is still on 'OpenSSH_8.4p1 Ubuntu-6ubuntu2.1, OpenSSL 1.1.1l 24 Aug 2021' but this will be a future problem.

[romanz]

Many thanks for reporting this issue!

[yanchenko-igor]

@antonionardella Please try PR #384

[onlykey]

@yanchenko-igor I tested the PR on Arch Linux and it fixes the issue thanks!