mkj/dropbear DROPBEAR_2020.79

Dropbear 2020.79

on GitHub

Support ed25519 hostkeys and authorized_keys, many thanks to Vladislav Grishenko.
This also replaces curve25519 with a TweetNaCl implementation that reduces code size.

Add chacha20-poly1305 authenticated cipher. This will perform faster than AES
on many platforms. Thanks to Vladislav Grishenko

Support using rsa-sha2 signatures. No changes are needed to hostkeys/authorized_keys
entries, existing RSA keys can be used with the new signature format (signatures
are ephemeral within a session). Old ssh-rsa signatures will no longer
be supported by OpenSSH in future so upgrading is recommended.

Use getrandom() call on Linux to ensure sufficient entropy has been gathered at startup.
Dropbear now avoids reading from the random source at startup, instead waiting until
the first connection. It is possible that some platforms were running without enough
entropy previously, those could potentially block at first boot generating host keys.
The dropbear "-R" option is one way to avoid that.

Upgrade libtomcrypt to 1.18.2 and libtommath to 1.2.0, many thanks to Steffen Jaeckel for
updating Dropbear to use the current API. Dropbear's configure script will check
for sufficient system library versions, otherwise using the bundled versions.

CBC ciphers, 3DES, hmac-sha1-96, and x11 forwarding are now disabled by default.
They can be set in localoptions.h if required.
Blowfish has been removed.

Support AES GCM, patch from Vladislav Grishenko. This is disabled by default,
Dropbear doesn't currently use hardware accelerated AES.

Added an API for specifying user public keys as an authorized_keys replacement.
See pubkeyapi.h for details, thanks to Fabrizio Bertocci

Fix idle detection clashing with keepalives, thanks to jcmathews

Include IP addresses in more early exit messages making it easier for fail2ban
processing. Patch from Kevin Darbyshire-Bryant

scp fix for CVE-2018-20685 where a server could modify name of output files

SSH_ORIGINAL_COMMAND is set for "dropbear -c" forced command too

Fix writing key files on systems without hard links, from Matt Robinson

Compatibility fixes for IRIX from Kazuo Kuroi

Re-enable printing MOTD by default, was lost moving from options.h. Thanks to zciendor

Call fsync() is called on parent directory when writing key files to ensure they are flushed

Fix "make install" for manpages in out-of-tree builds, from Gabor Z. Papp

Some notes are added in DEVELOPER.md