libssh2 removes unrecognized entries in known_hosts

[gnachman]

I use this code to add an entry to known_hosts:
https://github.com/NMSSH/NMSSH/blob/master/NMSSH/NMSSHSession.m#L710

I received a report that entries using unrecognized algorithms are getting removed:
https://gitlab.com/gnachman/iterm2/issues/4250

I confirmed this by creating a known_hosts file like this (personal data removed):

foo.bar.com ssh-rsa *redacted*
example.com ecdsa-sha2-nistp256 *redacted*

I then added a new host, and the ecdsa-sha2-nistp256 entry was removed. Entries whose algorithm field is ssh-rsa do not get clobbered.

[alamaison]

What version of libssh2 are you linking against? This was a known issue, but it was fixed 3 years ago. The fix first appeared in 1.5.0.

I've added some more test cases based on your specific example, but they all pass.

[gnachman]

Sorry about that! I will make sure to update to the most recent version.