In dns_rpz_update_from_db we call setup_update which creates the db
iterator and calls dns_dbiterator_first. This unpauses the iterator and
might cause db->tree_lock to be acquired. We then do isc_task_send(...)
on an event to do quantum_update, which (correctly) after each iteration
calls dns_dbiterator_pause, and re-isc_task_sends itself.
That's an obvious bug, as we're holding a lock over an async task send -
if a task requesting write (e.g. prune_tree) is scheduled on the same
workers queue as update_quantum but before it, it will wait for the
write lock indefinitely, resulting in a deadlock.
To fix it we have to pause dbiterator in setup_update.
Some system tests assume dig's default setings are in effect. While
these defaults may only be silently overridden (because of specific
options set in /etc/resolv.conf) for BIND releases using liblwres for
parsing /etc/resolv.conf (i.e. BIND 9.11 and older), it is arguably
prudent to make sure that tests relying on specific +timeout and +tries
settings specify these explicitly in their dig invocations, in order to
prevent test failures from being triggered by any potential changes to
current defaults.
When parsing message with DNS_MESSAGE_BESTEFFORT (used exclusively in
tools, never in named itself) if we hit an invalid SIG(0) in wrong
place we continue parsing the message, and put the sig0 in msg->sig0.
If we then hit another sig0 in a proper place we see that msg->sig0
is already 'taken' and we don't free name and rdataset, and we don't
set seen_problem. This causes an assertion failure.
This fixes that issue by setting seen_problem if we hit second sig0,
tsig or opt, which causes name and rdataset to be always freed.
Simply looking for the key ID surrounded by spaces in the tested
dnssec-signzone output file is not a precise enough method of checking
for signatures prepared using a given key ID: it can be tripped up by
cross-algorithm key ID collisions and certain low key IDs (e.g. 60, the
TTL specified in bin/tests/system/dnssec/signer/example.db.in), which
triggers false positives for the "dnssec" system test. Make key ID
extraction precise by using an awk script which operates on specific
fields.
The "mirror" system test expects all dig queries (including recursive
ones) to be responded to within 1 second, which turns out to be overly
optimistic in certain cases and leads to false positives being
triggered. Increase dig query timeout used throughout the "mirror"
system test to 2 seconds in order to alleviate the issue.
Currently, ns3 in the "mirror" system test sends trust anchor telemetry
queries every second as it is started with "-T tat=1". Given the number
of trust anchors configured on ns3 (9), TAT-related traffic clutters up
log files, hindering troubleshooting efforts. Increase TAT query
interval to 3 seconds in order to alleviate the issue.
Note that the interval chosen cannot be much higher if intermittent test
failures are to be avoided: TAT queries are only sent after the
configured number of seconds passes since resolver startup. Quick
experiments show that even on contemporary hardware, ns3 should be
running for at least 5 seconds before it is first shut down, so a
3-second TAT query interval seems to be a reasonable, future-proof
compromise. Ensure the relevant check is performed before ns3 is first
shut down to emphasize this trade-off and make it more clear by what
time TAT queries are expected to be sent.
"rndc dumpdb" works asynchronously, i.e. the requested dump may not yet
be fully written to disk by the time "rndc" returns. Prevent false
positives for the "serve-stale" system test by only checking dump
contents after the line indicating that it is complete is written.
