Make the length of responses containing manual samples constant to
simplify the protocol. It was the only type of response that had a
variable length.
This reverts commit 2343e7a89c.
Before reading the n_samples field of the MANUAL_LIST reply, check if it
is actually contained in the received message. This does not change the
outcome of the client's length check as the returned length was always
larger than the length of the truncated reply and it was dropped anyway,
but it prevents the client from reading uninitialized memory.
To prevent an attacker using chronyd in an amplification attack, change
the protocol to include padding in request packets so that the largest
possible reply is not larger than the request. Request packets that
don't include this padding are ignored as invalid.
This is an incompatible change in the protocol. Clients from chrony
1.27, 1.28 and 1.29 will receive NULL reply with STT_BADPKTVERSION and
print "Protocol version mismatch". Clients from 1.26 and older will not
receive a reply as it would be larger than the request if it was padded
to be compatible with their protocol.
This is a verbatim copy of the files at that stage of the repository that was
built from the CVS import. It allows future development to see a bit of recent
history, but without carrying around the baggage going back to 1997. If that
is really required, git grafts can be used.
