This adds a "policy" hook into the logging framework's streams and
filters to replace the existing log filter predicates. The hook
signature is as follows:
hook(rec: any, id: Log::ID, filter: Log::Filter);
The logging manager invokes hooks on each log record. Hooks can veto
log records via a break, and modify them if necessary. Log filters
inherit the stream-level hook, but can override or remove the hook as
needed.
The distribution's existing log streams now come with pre-defined
hooks that users can add handlers to. Their name is standardized as
"log_policy" by convention, with additional suffixes when a module
provides multiple streams. The following adds a handler to the Conn
module's default log policy hook:
hook Conn::log_policy(rec: Conn::Info, id: Log::ID, filter: Log::Filter)
{
if ( some_veto_reason(rec) )
break;
}
By default, this handler will get invoked for any log filter
associated with the Conn::LOG stream.
The existing predicates are deprecated for removal in 4.1 but continue
to work.
This adds two new functions: `Conn::register_removal_hook()` and
`Conn::unregister_removal_hook()` for registering a hook function to be
called back during `connection_state_remove`. The benefit of using hook
callback approach is better scalability: the overhead of unrelated
protocols having to dispatch no-op `connection_state_remove` handlers is
avoided.
And switch Zeek's base scripts over to using it in place of
"connection_state_remove". The difference between the two is
that "connection_state_remove" is raised for all events while
"successful_connection_remove" excludes TCP connections that were never
established (just SYN packets). There can be performance benefits
to this change for some use-cases.
There's also a new event called ``connection_successful`` and a new
``connection`` record field named "successful" to help indicate this new
property of connections.
This also required updating a test that required a root-certificate that
was removed from the Mozilla store - the test now directly includes that
specific root-cert.
* origin/topic/johanna/tls-more-data:
Update NEWS for ssl changes.
SSL: test updates for record_layer version
Final touches to SSL events with record layer version.
Introduce ssl_plaintext_data event.
Add record layer version to event ssl_encrypted_data.
Add compression methods to ssl_client_hello event.
* origin/topic/jsiwek/empty-lines:
Add 'smtp_excessive_pending_cmds' weird
Fix SMTP command string comparisons
Improve handling of empty lines in several text protocol analyzers
Add rate-limiting sampling mechanism for weird events
Teach timestamp canonifier about timestamps before ~2001
The generation of weird events, by default, are now rate-limited
according to these tunable options:
- Weird::sampling_whitelist
- Weird::sampling_threshold
- Weird::sampling_rate
- Weird::sampling_duration
The new get_reporter_stats() BIF also allows one to query the
total number of weirds generated (pre-sampling) which the new
policy/misc/weird-stats.bro script uses periodically to populate
a weird_stats.log.
There's also new reporter BIFs to allow generating weirds from the
script-layer such that they go through the same, internal
rate-limiting/sampling mechanisms:
- Reporter::conn_weird
- Reporter::flow_weird
- Reporter::net_weird
Some of the code was adapted from previous work by Johanna Amann.
The way in which TLS 1.3 is negotiated was changed slightly in later
revisions of the standard. The final version is only sent in an
extension - while the version field in the server hello still shows TLS
1.2.
This patch makes ssl.log show the correct version again.
This commit fixes a few small issues.
* server key exchange parameters are only parsed when a named curve is
given.
* I removed the ssl-verbose.bro and moved the functionality into the
testcase.
The information that we get with these events is likely irrelevant to
the majority of Bro users; I do not think that we have to ship a
script that uses them by default. A script like this would be
something to publish via the Bro package manager instead; this is the
approach that we have taken with a number of the recent SSL addition.
* I marked the ssl_server_curve event as deprecated. More information is
contained in the new ssl_ecdh_server_params event.
This is an events that is probably seldomly (or never) directly used
by anyone; I plan to completely remove it right after the 2.6 release.
Closes#1830.
* origin/topic/johanna/ocsp-sct-validate: (82 commits)
Tiny script changes for SSL.
Update CT Log list
SSL: Update OCSP/SCT scripts and documentation.
Revert "add parameter 'status_type' to event ssl_stapled_ocsp"
Revert "parse multiple OCSP stapling responses"
SCT: Fix script error when mime type of file unknown.
SCT: another memory leak in SCT parsing.
SCT validation: fix small memory leak (public keys were not freed)
Change end-of-connection handling for validation
OCSP/TLS/SCT: Fix a number of test failures.
SCT Validate: make caching a bit less aggressive.
SSL: Fix type of ssl validation result
TLS-SCT: compile on old versions of OpenSSL (1.0.1...)
SCT: Add caching support for validation
SCT: Add signed certificate timestamp validation script.
SCT: Allow verification of SCTs in Certs.
SCT: only compare correct OID/NID for Cert/OCSP.
SCT: add validation of proofs for extensions and OCSP.
SCT: pass timestamp as uint64 instead of time
Add CT log information to Bro
...
Move from using CCS (before: established) to just doing certificate
validation at the end of the connection.
This is (again) more robust in the case of aborted connection. I am
moving this into a hook because of the complexity of the
end-of-connection handling for SSL.
This should probably be extended to not just handle SSL validation, but
all other logging constructs that are currently called in _established.
The dpd signature missed a few cases that are used for TLS 1.3,
especially when draft versions (which are all that we are seeing at the
moment) are being negotiated.
This fix mostly allows draft versions in the server hello (identified by
7F[version]; since we do not know how many drafts there will be, we are
currently allowing a rather safe upper limit.
This commit add the table SSL::ct_logs to Bro. This table is populated
with information about the currently active certificate transparency
logs (data from Google). The data can, e.g., be used to identify which
Logs are being used in SCTs.
Re-enable logging, now in policy because it probably is interesting to
no-one. We also only log ocsp replies.
Fix all tests.
Fix an issue where ocsp replies were added to the x.509 certificate
list.
This makes it much easier for protocols where the mime type is known in
advance like, for example, TLS. We now do no longer have to perform deep
script-level magic.
This event is the replacement for ssl_application_data, which is removed
in the same commit. It is more generic, containing more information than
ssl_application_dataand is raised for all SSL/TLS messages that are
exchanged before encryption starts.
It is used by Bro internally to determine when a TLS1.3 session has been
completely established. Apart from that, it can be used to, e.g.,
determine the record layer TLS version.
This change adds compression methods to the ssl_client_hello event. It
not being included was an oversight from a long time ago.
This change means that the signature of ssl_client_hello changes
slightly and scripts will have to be adjusted; since this is a commonly
used event, the impact of it might be higher than usually for event
changes.
