Ensure that an attacker cannot force a replay attack by intercepting an
SPA packet and the replaying it with the base64 version of "Salted__"
(for Rindael) or the "hQ" prefix (for GnuPG). This is an important fix.
The following comment was added into the fwknopd code:
/* Ignore any SPA packets that contain the Rijndael or GnuPG prefixes
* since an attacker might have tacked them on to a previously seen
* SPA packet in an attempt to get past the replay check. And, we're
* no worse off since a legitimate SPA packet that happens to include
* a prefix after the outer one is stripped off won't decrypt properly
* anyway because libfko would not add a new one.
*/
Conflicts:
lib/cipher_funcs.h
016098a254