Script incorrectly reports key type for OpenSSH 7.6

[Mudrekh]

Using a key specifically generated with ssh-keygen -t rsa-sha2-512 on a Ubuntu 18.04 server running OpenSSH 7.6 (possibly others) erroneously reports

You're using an RSA key with SHA-1.
This key will continue to work if it's already set up, but you should strongly
consider generating a new key with the following command and using it instead:
ssh-keygen -t ed25519
If the key hasn't been set up by the deadline, you'll either need to generate a
new one as listed above, or upgrade to OpenSSH 7.2 or newer.

The debug statement for this version of OpenSSH for the sign_and_send_pubkey looks like debug3: sign_and_send_pubkey: RSA SHA256:<KEY_IDENTIFIER>. It is missing the 'signing' portion that the script is expecting. However, adding this key to a repository and cloning still works since the key is valid.

[bk2204]

Thanks for the report. We'll try to take a look at getting things fixed.

I'll mention that there is no rsa-sha2-512 keytype; there's only ssh-rsa as far as key types. The choice of which RSA signature type to use is dependent on client and server and can't be controlled at key generation time.

[Mudrekh]

Hmmm from the docs I was referencing...

     -t dsa | ecdsa | ecdsa-sk | ed25519 | ed25519-sk | rsa
             Specifies the type of key to create.  The possible values
             are “dsa”, “ecdsa”, “ecdsa-sk”, “ed25519”, “ed25519-sk”, or
             “rsa”.

             This flag may also be used to specify the desired signature
             type when signing certificates using an RSA CA key.  The
             available RSA signature variants are “ssh-rsa” (SHA1
             signatures, not recommended), “rsa-sha2-256”, and
             “rsa-sha2-512” (the default).

So the -t flag I mentioned might be superfluous, I just wanted to be explicit on an older version of OpenSSH.