Dropbear 2015.68

[Matt Johnston]

Hi all,

Dropbear 2015.68 is released. It has a few performance
improvements as well as various small fixes and
enahncements.

https://matt.ucc.asn.au/dropbear/dropbear.html

Note that there is a new PGP key and tarballs have signatures in 
the releases/ directory.
Dropbear SSH Release Signing <matt at ucc.asn.au> F29C6773 2015-06-29
Key fingerprint F734 7EF2 EE2E 07A2 6762  8CA9 4493 1494 F29C 6773

Cheers,
Matt

2015.68 - Saturday 8 August 2015

- Reduce local data copying for improved efficiency. Measured 30%
  increase in throughput for connections to localhost

- Forwarded TCP ports connect asynchronously and try all available addresses
  (IPv4, IPv6, round robin DNS)

- Fix all compile warnings, many patches from Gaël Portay
  Note that configure with -Werror may not be successful on some platforms (OS X)
  and some configuration options may still result in unused variable
  warnings.

- Use TCP Fast Open on Linux if available. Saves a round trip at connection
  to hosts that have previously been connected. 
  Needs a recent Linux kernel and possibly "sysctl -w net.ipv4.tcp_fastopen=3"
  Client side is disabled by default pending further compatibility testing
  with networks and systems.

- Increase maximum command length to 9000 bytes

- Free memory before exiting, patch from Thorsten Horstmann. Useful for
  Dropbear ports to embedded systems and for checking memory leaks
  with valgrind. Only partially implemented for dbclient.
  This is disabled by default, enable with DROPBEAR_CLEANUP in sysoptions.h

- DROPBEAR_DEFAULT_CLI_AUTHKEY setting now always prepends home directory unless
  there is a leading slash (~ isn't treated specially)

- Fix small ECC memory leaks

- Tighten validation of Diffie-Hellman parameters, from Florent Daigniere of
  Matta Consulting. Odds of bad values are around 2**-512 -- improbable.

- Twofish-ctr cipher is supported though disabled by default

- Fix pre-authentication timeout when waiting for client SSH-2.0 banner, thanks
  to CL Ouyang

- Fix null pointer crash with restrictions in authorized_keys without a command, patch from
  Guilhem Moulin

- Ensure authentication timeout is handled while reading the initial banner,
  thanks to CL Ouyang for finding it.

- Fix null pointer crash when handling bad ECC keys. Found by afl-fuzz