mirror of
https://github.com/zeek/zeek.git
synced 2025-10-03 23:28:20 +00:00
af1809aaa3
This is a larger internal change that moves the analyzer
infrastructure to a more flexible model where the available analyzers
don't need to be hardcoded at compile time anymore. While currently
they actually still are, this will in the future enable external
analyzer plugins. For now, it does already add the capability to
dynamically enable/disable analyzers from script-land, replacing the
old Analyzer::Available() methods.
There are three major parts going into this:
- A new plugin infrastructure in src/plugin. This is independent
of analyzers and will eventually support plugins for other parts
of Bro as well (think: readers and writers). The goal is that
plugins can be alternatively compiled in statically or loadead
dynamically at runtime from a shared library. While the latter
isn't there yet, there'll be almost no code change for a plugin
to make it dynamic later (hopefully :)
- New analyzer infrastructure in src/analyzer. I've moved a number
of analyzer-related classes here, including Analyzer and DPM;
the latter now renamed to Analyzer::Manager. More will move here
later. Currently, there's only one plugin here, which provides
*all* existing analyzers. We can modularize this further in the
future (or not).
- A new script interface in base/framework/analyzer. I think that
this will eventually replace the dpm framework, but for now
that's still there as well, though some parts have moved over.
I've also remove the dpd_config table; ports are now configured via
the analyzer framework. For exmaple, for SSH:
const ports = { 22/tcp } &redef;
event bro_init() &priority=5
{
...
Analyzer::register_for_ports(Analyzer::ANALYZER_SSH, ports);
}
As you can see, the old ANALYZER_SSH constants have more into an enum
in the Analyzer namespace.
This is all hardly tested right now, and not everything works yet.
There's also a lot more cleanup to do (moving more classes around;
removing no longer used functionality; documenting script and C++
interfaces; regression tests). But it seems to generally work with a
small trace at least.
The debug stream "dpm" shows more about the loaded/enabled analyzers.
A new option -N lists loaded plugins and what they provide (including
those compiled in statically; i.e., right now it outputs all the
analyzers).
This is all not cast-in-stone yet, for some things we need to see if
they make sense this way. Feedback welcome.
105 lines
2.8 KiB
Text
105 lines
2.8 KiB
Text
##! Activates port-independent protocol detection and selectively disables
|
|
##! analyzers if protocol violations occur.
|
|
|
|
module DPD;
|
|
|
|
@load-sigs ./dpd.sig
|
|
|
|
export {
|
|
## Add the DPD logging stream identifier.
|
|
redef enum Log::ID += { LOG };
|
|
|
|
## The record type defining the columns to log in the DPD logging stream.
|
|
type Info: record {
|
|
## Timestamp for when protocol analysis failed.
|
|
ts: time &log;
|
|
## Connection unique ID.
|
|
uid: string &log;
|
|
## Connection ID containing the 4-tuple which identifies endpoints.
|
|
id: conn_id &log;
|
|
## Transport protocol for the violation.
|
|
proto: transport_proto &log;
|
|
## The analyzer that generated the violation.
|
|
analyzer: string &log;
|
|
## The textual reason for the analysis failure.
|
|
failure_reason: string &log;
|
|
|
|
## Disabled analyzer IDs. This is only for internal tracking
|
|
## so as to not attempt to disable analyzers multiple times.
|
|
disabled_aids: set[count];
|
|
};
|
|
|
|
## Ignore violations which go this many bytes into the connection.
|
|
## Set to 0 to never ignore protocol violations.
|
|
const ignore_violations_after = 10 * 1024 &redef;
|
|
}
|
|
|
|
redef record connection += {
|
|
dpd: Info &optional;
|
|
};
|
|
|
|
event bro_init() &priority=5
|
|
{
|
|
Log::create_stream(DPD::LOG, [$columns=Info]);
|
|
}
|
|
|
|
function foo() : string
|
|
{
|
|
return "HTTP";
|
|
}
|
|
|
|
event protocol_confirmation(c: connection, atype: Analyzer::Tag, aid: count) &priority=10
|
|
{
|
|
local analyzer = Analyzer::name(atype);
|
|
|
|
if ( fmt("-%s",analyzer) in c$service )
|
|
delete c$service[fmt("-%s", analyzer)];
|
|
|
|
add c$service[analyzer];
|
|
}
|
|
|
|
event protocol_violation(c: connection, atype: Analyzer::Tag, aid: count,
|
|
reason: string) &priority=10
|
|
{
|
|
local analyzer = Analyzer::name(atype);
|
|
# If the service hasn't been confirmed yet, don't generate a log message
|
|
# for the protocol violation.
|
|
if ( analyzer !in c$service )
|
|
return;
|
|
|
|
delete c$service[analyzer];
|
|
add c$service[fmt("-%s", analyzer)];
|
|
|
|
local info: Info;
|
|
info$ts=network_time();
|
|
info$uid=c$uid;
|
|
info$id=c$id;
|
|
info$proto=get_conn_transport_proto(c$id);
|
|
info$analyzer=analyzer;
|
|
info$failure_reason=reason;
|
|
c$dpd = info;
|
|
}
|
|
|
|
event protocol_violation(c: connection, atype: Analyzer::Tag, aid: count, reason: string) &priority=5
|
|
{
|
|
if ( !c?$dpd || aid in c$dpd$disabled_aids )
|
|
return;
|
|
|
|
local size = c$orig$size + c$resp$size;
|
|
if ( ignore_violations_after > 0 && size > ignore_violations_after )
|
|
return;
|
|
|
|
# Disable the analyzer that raised the last core-generated event.
|
|
disable_analyzer(c$id, aid);
|
|
add c$dpd$disabled_aids[aid];
|
|
}
|
|
|
|
event protocol_violation(c: connection, atype: Analyzer::Tag, aid: count,
|
|
reason: string) &priority=-5
|
|
{
|
|
if ( c?$dpd )
|
|
{
|
|
Log::write(DPD::LOG, c$dpd);
|
|
delete c$dpd;
|
|
}
|
|
}
|