Add support for certificate key types for users and hosts.

OpenSSH certificate key types are not X.509 certificates, but a much
simpler format that encodes a public key, identity information and
some validity constraints and signs it with a CA key. CA keys are
regular SSH keys. This certificate style avoids the attack surface
of X.509 certificates and is very easy to deploy.

Certified host keys allow automatic acceptance of new host keys
when a CA certificate is marked as trusted in ~/.ssh/known_hosts.
see VERIFYING HOST KEYS in ssh(1) for details.

Certified user keys allow authentication of users when the signing
CA key is marked as trusted in authorized_keys. See "AUTHORIZED_KEYS
FILE FORMAT" in sshd(8) for details.

Certificates are minted using ssh-keygen(1), documentation is in
the "CERTIFICATES" section of that manpage.

Documentation on the format of certificates is in the file
PROTOCOL.certkeys

feedback and ok markus@

1 files changed, 3 insertions, 2 deletions

diff --git a/usr.bin/ssh/auth.h b/usr.bin/ssh/auth.h
index e4495e42a9c..bcadcba159f 100644
--- a/usr.bin/ssh/auth.h
+++ b/usr.bin/ssh/auth.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.h,v 1.63 2009/08/15 18:56:34 fgsch Exp $ */
+/* $OpenBSD: auth.h,v 1.64 2010/02/26 20:29:54 djm Exp $ */
 
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
@@ -155,7 +155,8 @@ check_key_in_hostfiles(struct passwd *, Key *, const char *,
 
 /* hostkey handling */
 Key	*get_hostkey_by_index(int);
-Key	*get_hostkey_by_type(int);
+Key	*get_hostkey_public_by_type(int);
+Key	*get_hostkey_private_by_type(int);
 int	 get_hostkey_index(Key *);
 int	 ssh1_session_key(BIGNUM *);