diff options
Diffstat (limited to 'crypto/openssh/PROTOCOL')
| -rw-r--r-- | crypto/openssh/PROTOCOL | 53 |
1 files changed, 50 insertions, 3 deletions
diff --git a/crypto/openssh/PROTOCOL b/crypto/openssh/PROTOCOL index aa59f58..91bfe27 100644 --- a/crypto/openssh/PROTOCOL +++ b/crypto/openssh/PROTOCOL @@ -40,8 +40,8 @@ http://www.openssh.com/txt/draft-miller-secsh-compression-delayed-00.txt "ecdsa-sha2-nistp521-cert-v01@openssh.com" OpenSSH introduces new public key algorithms to support certificate -authentication for users and hostkeys. These methods are documented in -the file PROTOCOL.certkeys +authentication for users and host keys. These methods are documented +in the file PROTOCOL.certkeys 1.4. transport: Elliptic Curve cryptography @@ -282,6 +282,53 @@ by the client cancel the forwarding of a Unix domain socket. boolean FALSE string socket path +2.5. connection: hostkey update and rotation "hostkeys-00@openssh.com" +and "hostkeys-prove-00@openssh.com" + +OpenSSH supports a protocol extension allowing a server to inform +a client of all its protocol v.2 host keys after user-authentication +has completed. + + byte SSH_MSG_GLOBAL_REQUEST + string "hostkeys-00@openssh.com" + string[] hostkeys + +Upon receiving this message, a client should check which of the +supplied host keys are present in known_hosts. For keys that are +not present, it should send a "hostkeys-prove@openssh.com" message +to request the server prove ownership of the private half of the +key. + + byte SSH_MSG_GLOBAL_REQUEST + string "hostkeys-prove-00@openssh.com" + char 1 /* want-reply */ + string[] hostkeys + +When a server receives this message, it should generate a signature +using each requested key over the following: + + string "hostkeys-prove-00@openssh.com" + string session identifier + string hostkey + +These signatures should be included in the reply, in the order matching +the hostkeys in the request: + + byte SSH_MSG_REQUEST_SUCCESS + string[] signatures + +When the client receives this reply (and not a failure), it should +validate the signatures and may update its known_hosts file, adding keys +that it has not seen before and deleting keys for the server host that +are no longer offered. + +These extensions let a client learn key types that it had not previously +encountered, thereby allowing it to potentially upgrade from weaker +key algorithms to better ones. It also supports graceful key rotation: +a server may offer multiple keys of the same type for a period (to +give clients an opportunity to learn them using this extension) before +removing the deprecated key from those offered. + 3. SFTP protocol changes 3.1. sftp: Reversal of arguments to SSH_FXP_SYMLINK @@ -406,4 +453,4 @@ respond with a SSH_FXP_STATUS message. This extension is advertised in the SSH_FXP_VERSION hello with version "1". -$OpenBSD: PROTOCOL,v 1.24 2014/07/15 15:54:14 millert Exp $ +$OpenBSD: PROTOCOL,v 1.27 2015/02/20 22:17:21 djm Exp $ |
