While we support initializing records via coercion from an expression
list, e.g.,
local x: X = [$x1=1, $x2=2];
this can sometimes obscure the code to readers, e.g., when assigning to
value declared and typed elsewhere. The language runtime has a similar
overhead since instead of just constructing a known type it needs to
check at runtime that the coercion from the expression list is valid;
this can be slower than just writing the readible code in the first
place, see #4559.
With this patch we use explicit construction, e.g.,
local x = X($x1=1, $x2=2);
This field is used internally to trace which analyzers already had a
violation. This is mostly used to prevent duplicate logging.
In the past, c$service_violation was used for a similar purpose -
however it has slightly different semantics. Where c$failed_analyzers
tracks analyzers that were removed due to a violation,
c$service_violation tracks violations - and doesn't care if an analyzer
was actually removed due to it.
To address review feedback in GH-4362: rename analyzer-failed-log.zeek
to loggig.zeek, analyzer-debug-log.zeek to debug-logging.zeek and
dpd-log.zeek to deprecated-dpd-log.zeek.
Includes respective test, NEWS, etc updates.
The current analyzer.log is more useful for debugging than for
operational purposes. Hence this is disabled by default, moved to a
policy script, and the log is renamed to analyzer-debug.log.
Furthermore, logging of analyzer confirmations and disabling analyzers
are now enabled by default.
This commit revamps the handling of analyzer violations that happen
before an analyzer confirms the protocol.
The current state is that an analyzer is disabled after 5 violations, if
it has not been confirmed. If it has been confirmed, it is disabled
after a single violation.
The reason for this is a historic mistake. In Zeek up to versions 1.5,
analyzers were unconditianally removed when they raised the first
protocol violation.
When this script was ported to the new layout for Zeek 2.0 in
b4b990cfb5, a logic error was introduced
that caused analyzers to no longer be disabled if they were not
confirmed.
This was the state for ~8 years, till the DPD::max_violations options
was added, which instates the current approach of disabling unconfirmed
analyzers after 5 violations. Sadly, there is not much discussion about
this change - from my hazy memory, I think this was discovered during
performance tests and the new behavior was added without checking into
the history of previous changes.
This commit reinstates the originally intended behavior of DPD. When an
analyzer that has not been confirmed raises a protocol violation, it is
immediately removed from the connection. This also makes a lot of sense
- this allows the analyzer to be in a "tasting" phase at the beginning
of the connection, and to error out quickly once it realizes that it was
attached to a connection not containing the desired protocol.
This change also removes the DPD::max_violations option, as it no longer
serves any purpose after this change. (In practice, the option remains
with an &deprecated warning, but it is no longer used for anything).
There are relatively minimal test-baseline changes due to this; they are
mostly triggered by the removal of the data structure and by less
analyzer errors being thrown, as unconfirmed analyzers are disabled
after the first error.
By default this only logs all the violations, regardless of the
confirmation state (for which there's still dpd.log). It includes
packet, protocol and file analyzers.
This uses options, change handlers and event groups for toggling
the functionality at runtime.
Closes#2031
