Michael Rash, Security Researcher

Software Release - fwknop-2.0.1

fwknop-2.0.1 released The fwknop-2.0.1 release is fwknop is available for download. This is mainly a bug fix release before the new HMAC-SHA256 work is ready for general consumption. A couple of the fixes are important for PF users on OpenBSD and for people who use the same encryption key within multiple access stanzas.

Here is the complete fwknop-2.0.1 ChangeLog:

  • [server] Bug fix where the same encryption key used for two stanzas in the access.conf file would result in access requests that matched the second stanza to always be treated as a replay attack. This has been fixed for the fwknop-2.0.1 release, and was reported by Andy Rowland. Now the fwknopd server computes the SHA256 digest of raw incoming payload data before decryption, and compares this against all previous hashes. Previous to this commit, fwknopd would add a new hash to the replay digest list right after the first access.conf stanza match, so when SPA packet data matched the second access.conf stanza a matching replay digest would already be there.
  • [server] Updated PCAP_LOOP_SLEEP default to 1/10th of a second (in microseconds). This was supposed to be the default anyway, but C Anthony Risinger reported a bug where fwknopd was consuming more resources than necessary, and the cause was PCAP_LOOP_SLEEP set by default to 1/100th of a second - this has been fixed.
  • [libfko] Added SPA message validation calls to fko decoding routines to help ensure that SPA messages conform to expected values.
  • Bug fix for PF firewalls: updated the PF anchor check to not rely on listing the PF policy - fwknopd now uses 'pfctl -s Anchor' instead.
  • [test suite] Added parsing of valgrind output to produce a listing of functions that have been flagged - this assists in the development process to ensure that fwknop is not leaking memory.
  • [test suite] Bug fix on Mac OS X systems to account for libfko.dylib path instead of This fixes the existence check for libfko.
  • [test suite] Added tests for --nat-local mode.
  • [client] Fixed several minor memory leaks caught by valgrind.
  • [libfko] Minor gcc warning fix: fko_decode.c:43:17: warning: variable ‘edata_size’ set but not used [-Wunused-but-set-variable].
  • Updated fwknopd init script for Debian systems (contributed by Franck Joncourt).
The complete fwknop-2.0.1 ChangeLog can be found here via the fwknop gitweb interface.