[ssh_x509] openssh X509 map CN with SSH_MSG_USERAUTH_REQUEST

[ssh_x509 at roumenpetrov.info]

Public key authentification need another mehanism for maping user.
openssh protocol expect SSH_MSG_USERAUTH_REQUEST message, so like i
demonstrate in first post we can isely impoersonate someone during ssh
logon if we copy authkeyz to impersonate user home directory.   With
only user/passwors authenification this same impersonation require to
know user password...

So can we somehow patch openssh source code to read from X509v3
certificate only CN or principal name or something we want and pair
with username we provide when we try to ssh. And if this not mach, we
abort logon.

Regards,
Goran.