Another niceness of OpenSSL is that if the high-order bit of a 521-bit
big num is not set then BN_bn2bin() will just return 65 bytes instead of
66 bytes with the 1st (big endian, after all) being all zero. When this
happens the wrong number of octets are mixed into function H(). So
there's a whole bunch of "offset" computations and BN_bn2bin() dumps the
big number into a buffer + offset. That should be obvious in the patch
too.
The changes are:
1. the word "and" in the hunting-and-pecking string passed to the KDF
should be capitalized.
2. the primebitlen used in the KDF should be a short not an int.
3. the computation of MK in hostap is based on an older version of the
draft and is not the way it's specified in the RFC.
4. the group being passed into computation of the Commit was not in
network order.