Encrypted key with new OpenSSH header for private keys seems to be broken

[Soulou]

-----BEGIN OPENSSH PRIVATE KEY-----

User wasn't able to type their passphrase, it was directly displaying an error:

Fail to connect to SSH server: Invalid SSH key or password: ssh: cannot decode encrypted private keys

[EtienneM]

https://app.intercom.io/a/apps/w4oogu7s/inbox/inbox/search/conversations/23446486723

[EtienneM]

Same issue with scalingo login --ssh --ssh-identity ./test

[EtienneM]

This is kind of related to #389. Except that now the issue only arise when the key is encrypted with a passphrase. Actually the dependency we use to read private key files is golang.org/x/crypto/ssh. And it seems it is not yet able to read such files: https://github.com/golang/crypto/blob/master/ssh/keys.go#L878-L880

[EtienneM]

Oh no... It's just that our code calls ssh.ParsePrivateKey instead of ParsePrivateKeyWithPassphrase if needed

[EtienneM]

The issue is that we fail to detect the key is encrypted. We check this like that: strings.Contains(p.Block.Headers["Proc-Type"], "ENCRYPTED"). The golang.org/x/crypto/ssh does the same thing so it's probably how we should handle that. But the header in my case is empty:

TYPE: "OPENSSH PRIVATE KEY"
HEADERS: map[string]string{}

[Soulou]

Actually it's because this Proc-Type header is only present in the old format.

With the new format, there is no PEM header to re at all.

[EtienneM]

up : https://app.intercom.io/a/apps/w4oogu7s/inbox/inbox/all/conversations/24870997728