Hello list, I'm not sure whether this is bug worthy or just my own insanity. I'm using 6.4p1 packages from Debian jessie and wheezy-backports. I like VisualHostKey, although it may not add any protection (other than not trusting ones own known_hosts file?), I've become accustomed to it as it seems that extra neurons fire when I log into a host and get a visual cue of what looks like a strawberry or jester hat and suddenly a catalog of frequent commands relevant to the particular host surface in mind ;-) I have two configuration problems that make VisualHostKey less usable. * RekeyLimit I'm no crypto expert, pretty much cargo-culting here, but from bits and pieces I've read, it seems like re-keying is crucial for a cipher like AES-GCM. Maybe it's just a gut feeling inspired by strongSwan IPsec daemons which are constantly re-keying. Every time the cipher is re-keyed, VisualHostKey clobbers the terminal, usually with broken line feeds such that the ascii-art is unintelligible and wraps off the right side of the terminal. This is annoying, especially with a screen(1) full of ssh sessions that may be idle and re-keyed several times over a weekend, coming back and having to work through clearing the screens of each session (^L suffices for a shell or emacs, but sometimes the session is in a curses application, or lost information while tailing a log, etc.). This gets uglier when making use of the fantastic ControlPersist options - seemingly logged out ssh session still blast the initial terminal with re-keying fingerprints. * VerifyHostKeyDNS=yes It seems VerifyHostKeyDNS=yes short-circuits VisualHostKey - it's neither displayed on initial connection, or on re-keying (good). So I have a funny setup: For hosts which have SSHFP records, I have set VerifyHostKeyDNS=yes and ineffectively set VisualHostKey=yes (never prints), and can also set a timed RekeyLimit rate. For hosts which don't have SSHFP, I could leave RekeyLimit at the default (1G none) and rarely see the re-key fingerprints, however in an all-or-nothing sort of decision, simply set VisualHostKey=no and be done with it. Am I missing something? Is there a way to comfortably get VisualHostKey back? Perhaps a trivial/wishlist bug with re-keying should be filed? Perhaps this is already solved by bug 2154, "Avoid key lookup overhead when re-keying": https://bugzilla.mindrot.org/show_bug.cgi?id=2154 P.S. I think it's wonderful you folks are working on curve25519, ed25519, and chacha20+poly1305. I've moved a bunch of systems to ECDHE last year, great speedup, especially from crap Atom clients, but feel that I've shot myself in the foot after Schneier's denouncement of the NIST curves. -- Gerald Turner Email: gturner at unzane.com JID: gturner at unzane.com GPG: 0xFA8CD6D5 21D9 B2E8 7FE7 F19E 5F7D 4D0C 3FA0 810F FA8C D6D5 -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 197 bytes Desc: not available URL: <http://lists.mindrot.org/pipermail/openssh-unix-dev/attachments/20140102/0c48aa5d/attachment.bin>
