Log Message:
update dropbear to 2016.74.  changes:

2016.74 - 21 July 2016

- Security: Message printout was vulnerable to format string injection.

  If specific usernames including "%" symbols can be created on a system
  (validated by getpwnam()) then an attacker could run arbitrary code as root
  when connecting to Dropbear server.

  A dbclient user who can control username or host arguments could potentially
  run arbitrary code as the dbclient user. This could be a problem if scripts
  or webpages pass untrusted input to the dbclient program.
  CVE-2016-7406
  https://secure.ucc.asn.au/hg/dropbear/rev/b66a483f3dcb

- Security: dropbearconvert import of OpenSSH keys could run arbitrary code as
  the local dropbearconvert user when parsing malicious key files
  CVE-2016-7407
  https://secure.ucc.asn.au/hg/dropbear/rev/34e6127ef02e

- Security: dbclient could run arbitrary code as the local dbclient user if
  particular -m or -c arguments are provided. This could be an issue where
  dbclient is used in scripts.
  CVE-2016-7408
  https://secure.ucc.asn.au/hg/dropbear/rev/eed9376a4ad6

- Security: dbclient or dropbear server could expose process memory to the
  running user if compiled with DEBUG_TRACE and running with -v
  CVE-2016-7409
  https://secure.ucc.asn.au/hg/dropbear/rev/6a14b1f6dc04

  The security issues were reported by an anonymous researcher working with
  Beyond Security's SecuriTeam Secure Disclosure www.beyondsecurity.com/ssd.html

- Fix port forwarding failure when connecting to domains that have both
  IPv4 and IPv6 addresses. The bug was introduced in 2015.68

- Fix 100% CPU use while waiting for rekey to complete. Thanks to Zhang Hui P
  for the patch

2016.73 - 18 March 2016

- Support syslog in dbclient, option -o usesyslog=yes. Patch from Konstantin Tokarev

- Kill a proxycommand when dbclient exits, patch from Konstantin Tokarev

- Option to exit when a TCP forward fails, patch from Konstantin Tokarev

- New "-o" option parsing from Konstantin Tokarev. This allows \ 
handling some extra options
  in the style of OpenSSH, though implementing all OpenSSH options is not planned.

- Fix crash when fallback initshells() is used, reported by Michael Nowak and \ 
Mike Tzou

- Allow specifying commands eg "dropbearmulti dbclient ..." instead of \ 
symlinks

- Various cleanups for issues found by a lint tool, patch from Francois Perrad

- Fix tab indent consistency, patch from Francois Perrad

- Fix issues found by cppcheck, reported by Mike Tzou

- Use system memset_s() or explicit_bzero() if available to clear memory. Also make
  libtomcrypt/libtommath routines use that (or Dropbear's own m_burn()).

- Prevent scp failing when the local user doesn't exist. Based on patch from \ 
Michael Witten.

- Improved Travis CI test running, thanks to Mike Tzou

- Improve some code that was flagged by Coverity and Fortify Static Code Analyzer

2016.72 - 9 March 2016

- Validate X11 forwarding input. Could allow bypass of authorized_keys command= \ 
restrictions,
  found by github.com/tintinweb. Thanks for Damien Miller for a patch. CVE-2016-3116
  https://secure.ucc.asn.au/hg/dropbear/rev/a3e8389e01ff

2015.71 - 3 December 2015

- Fix "bad buf_incrpos" when data is transferred, broke in 2015.69

- Fix crash on exit when -p address:port is used, broke in 2015.68, thanks to
  Frank Stollenwerk for reporting and investigation

- Fix building with only ENABLE_CLI_REMOTETCPFWD given, patch from Konstantin Tokarev

- Fix bad configure script test which didn't work with dash shell, patch from \ 
Juergen Daubert,
  broke in 2015.70

- Fix server race condition that could cause sessions to hang on exit,
  https://github.com/robotframework/SSHLibrary/issues/128

2015.70 - 26 November 2015

- Fix server password authentication on Linux, broke in 2015.69

2015.69 - 25 November 2015

- Fix crash when forwarded TCP connections fail to connect (bug introduced in \ 
2015.68)

- Avoid hang on session close when multiple sessions are started, affects Qt Creator
  Patch from Andrzej Szombierski

- Reduce per-channel memory consumption in common case, increase default
  channel limit from 100 to 1000 which should improve SOCKS forwarding for modern
  webpages

- Handle multiple command line arguments in a single flag, thanks to Guilhem Moulin

- Manpage improvements from Guilhem Moulin

- Build fixes for Android from Mike Frysinger

- Don't display the MOTD when an explicit command is run from Guilhem Moulin

- Check curve25519 shared secret isn't zero

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

2015.67 - Wednesday 28 January 2015

- Call fsync() after generating private keys to ensure they aren't lost if a
  reboot occurs. Thanks to Peter Korsgaard

- Disable non-delayed zlib compression by default on the server. Can be
  enabled if required for old clients with DROPBEAR_SERVER_DELAY_ZLIB

- Default client key path ~/.ssh/id_dropbear

- Prefer stronger algorithms by default, from Fedor Brunner.
  AES256 over 3DES
  Diffie-hellman group14 over group1

- Add option to disable CBC ciphers.

- Disable twofish in default options.h

- Enable sha2 HMAC algorithms by default, the code was already required
  for ECC key exchange. sha1 is the first preference still for performance.

- Fix installing dropbear.8 in a separate build directory, from Like Ma

- Allow configure to succeed if libtomcrypt/libtommath are missing, from Elan \ 
Ruusamäe

- Don't crash if ssh-agent provides an unknown type of key. From Catalin Patulea

- Minor bug fixes, a few issues found by Coverity scan

2014.66 - Thursday 23 October 2014

- Use the same keepalive handling behaviour as OpenSSH. This will work better
  with some SSH implementations that have different behaviour with unknown
  message types.

- Don't reply with SSH_MSG_UNIMPLEMENTED when we receive a reply to our own
  keepalive message

- Set $SSH_CLIENT to keep bash happy, patch from Ryan Cleere

- Fix wtmp which broke since 2013.62, patch from Whoopie

2014.65 - Friday 8 August 2014

- Fix 2014.64 regression, server session hang on exit with scp (and probably
  others), thanks to NiLuJe for tracking it down

- Fix 2014.64 regression, clock_gettime() error handling which broke on older
  Linux kernels, reported by NiLuJe

- Fix 2014.64 regression, writev() could occassionally fail with EAGAIN which
  wasn't caught

- Avoid error message when trying to set QoS on proxycommand or multihop pipes

- Use /usr/bin/xauth, thanks to Mike Frysinger

- Don't exit the client if the local user entry can't be found, thanks to iquaba

2014.64 - Sunday 27 July 2014

- Fix compiling with ECDSA and DSS disabled

- Don't exit abruptly if too many outgoing packets are queued for writev(). Patch
  thanks to Ronny Meeus

- The -K keepalive option now behaves more like OpenSSH's \ 
"ServerAliveInterval".
  If no response is received after 3 keepalives then the session is terminated. This
  will close connections faster than waiting for a TCP timeout.

- Rework TCP priority setting. New settings are
	if (connecting || ptys || x11) tos = LOWDELAY
	else if (tcp_forwards) tos = 0
	else tos = BULK
  Thanks to Catalin Patulea for the suggestion.

- Improve handling of many concurrent new TCP forwarded connections, should now
  be able to handle as many as MAX_CHANNELS. Thanks to Eduardo Silva for reporting
  and investigating it.

- Make sure that exit messages from the client are printed, regression in 2013.57

- Use monotonic clock where available, timeouts won't be affected by system time
  changes

- Add -V for version

2014.63 - Wednesday 19 February 2014

- Fix ~. to terminate a client interactive session after waking a laptop
  from sleep.

- Changed port separator syntax again, now using host^port. This is because
  IPv6 link-local addresses use %. Reported by Gui Iribarren

- Avoid constantly relinking dropbearmulti target, fix "make install"
  for multi target, thanks to Mike Frysinger

- Avoid getting stuck in a loop writing huge key files, reported by Bruno
  Thomsen

- Don't link dropbearkey or dropbearconvert to libz or libutil,
  thanks to Nicolas Boos

- Fix linking -lcrypt on systems without /usr/lib, thanks to Nicolas Boos

- Avoid crash on exit due to cleaned up keys before last packets are sent,
  debugged by Ronald Wahl

- Fix a race condition in rekeying where Dropbear would exit if it received a
  still-in-flight packet after initiating rekeying. Reported by Oliver Metz.
  This is a longstanding bug but is triggered more easily since 2013.57

- Fix README for ecdsa keys, from Catalin Patulea

- Ensure that generated RSA keys are always exactly the length
  requested. Previously Dropbear always generated N+16 or N+15 bit keys.
  Thanks to Unit 193

- Fix DROPBEAR_CLI_IMMEDIATE_AUTH mode which saves a network round trip if the
  first public key succeeds. Still not enabled by default, needs more
  compatibility testing with other implementations.

- Fix for port 0 forwarding in the client and port forwarding with Apache MINA SSHD.

- Fix for bad system linux/pkt-sched.h header file with older Linux
kernels, from Steve Dover

- Fix signal handlers so that errno is saved, thanks to Erik Ahlén for a patch
  and Mark Wickham for independently spotting the same problem.