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Add ability to provide external rules reader/collector/compiler

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In some cases, a user of the falco engine may want to extend the falco
rules format to provide additional objects to the rules file.

To support that, add a new method set_rule_loader() that allows a user
to provide classes that derive from
rule_loader::{reader,collector,compiler} and read those additional
objects from the rules file.

Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
This commit is contained in:
Mark Stemm
2024-01-11 12:46:07 -08:00
committed by poiana
parent f66780eb81
commit 2d0159ae05
2 changed files with 66 additions and 22 deletions
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69
userspace/engine/falco_engine.cpp
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@@ -27,6 +27,7 @@ limitations under the License.
#include <string>
#include <fstream>
#include <functional>
#include <memory>
#include <utility>
#include <vector>
@@ -38,8 +39,6 @@ limitations under the License.
#include "falco_engine.h"
#include "falco_utils.h"
#include "falco_engine_version.h"
#include "rule_loader_reader.h"
#include "rule_loader_compiler.h"
#include "formats.h"
@@ -53,6 +52,9 @@ using namespace falco;
falco_engine::falco_engine(bool seed_rng)
: m_syscall_source(NULL),
m_syscall_source_idx(SIZE_MAX),
m_rule_reader(std::make_shared<rule_loader::reader>()),
m_rule_collector(std::make_shared<rule_loader::collector>()),
m_rule_compiler(std::make_shared<rule_loader::compiler>()),
m_next_ruleset_id(0),
m_min_priority(falco_common::PRIORITY_DEBUG),
m_sampling_ratio(1), m_sampling_multiplier(0),
@@ -69,7 +71,7 @@ falco_engine::falco_engine(bool seed_rng)
falco_engine::~falco_engine()
{
m_rules.clear();
m_rule_collector.clear();
m_rule_collector->clear();
m_rule_stats_manager.clear();
m_sources.clear();
}
@@ -79,6 +81,36 @@ sinsp_version falco_engine::engine_version()
return sinsp_version(FALCO_ENGINE_VERSION);
}
void falco_engine::set_rule_reader(std::shared_ptr<rule_loader::reader> reader)
{
m_rule_reader = reader;
}
std::shared_ptr<rule_loader::reader> falco_engine::get_rule_reader()
{
return m_rule_reader;
}
void falco_engine::set_rule_collector(std::shared_ptr<rule_loader::collector> collector)
{
m_rule_collector = collector;
}
std::shared_ptr<rule_loader::collector> falco_engine::get_rule_collector()
{
return m_rule_collector;
}
void falco_engine::set_rule_compiler(std::shared_ptr<rule_loader::compiler> compiler)
{
m_rule_compiler = compiler;
}
std::shared_ptr<rule_loader::compiler> falco_engine::get_rule_compiler()
{
return m_rule_compiler;
}
// Return a key that uniquely represents a field class.
// For now, we assume name + shortdesc is unique.
static std::string fieldclass_key(const gen_event_filter_factory::filter_fieldclass_info &fld_info)
@@ -164,12 +196,11 @@ std::unique_ptr<load_result> falco_engine::load_rules(const std::string &rules_c
cfg.replace_output_container_info = m_replace_container_info;
// read rules YAML file and collect its definitions
rule_loader::reader reader;
if (reader.read(cfg, m_rule_collector))
if(m_rule_reader->read(cfg, *(m_rule_collector.get())))
{
// compile the definitions (resolve macro/list refs, exceptions, ...)
m_last_compile_output = std::make_unique<rule_loader::compiler::compile_output>();
rule_loader::compiler().compile(cfg, m_rule_collector, *m_last_compile_output.get());
m_last_compile_output = m_rule_compiler->new_compile_output();
m_rule_compiler->compile(cfg, *(m_rule_collector.get()), *m_last_compile_output.get());
// clear the rules known by the engine and each ruleset
m_rules.clear();
@@ -187,7 +218,7 @@ std::unique_ptr<load_result> falco_engine::load_rules(const std::string &rules_c
continue;
}
auto info = m_rule_collector.rules().at(rule.name);
auto info = m_rule_collector->rules().at(rule.name);
if (!info)
{
// this is just defensive, it should never happen
@@ -465,12 +496,12 @@ nlohmann::json falco_engine::describe_rule(std::string *rule, const std::vector<
if(!rule)
{
// Store required engine version
auto required_engine_version = m_rule_collector.required_engine_version();
auto required_engine_version = m_rule_collector->required_engine_version();
output["required_engine_version"] = required_engine_version.version.as_string();
// Store required plugin versions
nlohmann::json plugin_versions = nlohmann::json::array();
auto required_plugin_versions = m_rule_collector.required_plugin_versions();
auto required_plugin_versions = m_rule_collector->required_plugin_versions();
for(const auto& req : required_plugin_versions)
{
nlohmann::json r;
@@ -495,7 +526,7 @@ nlohmann::json falco_engine::describe_rule(std::string *rule, const std::vector<
nlohmann::json rules_array = nlohmann::json::array();
for(const auto& r : m_last_compile_output->rules)
{
auto info = m_rule_collector.rules().at(r.name);
auto info = m_rule_collector->rules().at(r.name);
nlohmann::json rule;
get_json_details(rule, r, *info, plugins);
rules_array.push_back(std::move(rule));
@@ -506,7 +537,7 @@ nlohmann::json falco_engine::describe_rule(std::string *rule, const std::vector<
nlohmann::json macros_array = nlohmann::json::array();
for(const auto &m : m_last_compile_output->macros)
{
auto info = m_rule_collector.macros().at(m.name);
auto info = m_rule_collector->macros().at(m.name);
nlohmann::json macro;
get_json_details(macro, m, *info, plugins);
macros_array.push_back(std::move(macro));
@@ -517,7 +548,7 @@ nlohmann::json falco_engine::describe_rule(std::string *rule, const std::vector<
nlohmann::json lists_array = nlohmann::json::array();
for(const auto &l : m_last_compile_output->lists)
{
auto info = m_rule_collector.lists().at(l.name);
auto info = m_rule_collector->lists().at(l.name);
nlohmann::json list;
get_json_details(list, l, *info, plugins);
lists_array.push_back(std::move(list));
@@ -527,7 +558,7 @@ nlohmann::json falco_engine::describe_rule(std::string *rule, const std::vector<
else
{
// build json information for just the specified rule
auto ri = m_rule_collector.rules().at(*rule);
auto ri = m_rule_collector->rules().at(*rule);
if(ri == nullptr || ri->unknown_source)
{
throw falco_exception("Rule \"" + *rule + "\" is not loaded");
@@ -571,12 +602,12 @@ void falco_engine::get_json_details(
filter_details details;
filter_details compiled_details;
nlohmann::json json_details;
for(const auto &m : m_rule_collector.macros())
for(const auto &m : m_rule_collector->macros())
{
details.known_macros.insert(m.name);
compiled_details.known_macros.insert(m.name);
}
for(const auto &l : m_rule_collector.lists())
for(const auto &l : m_rule_collector->lists())
{
details.known_lists.insert(l.name);
compiled_details.known_lists.insert(l.name);
@@ -672,12 +703,12 @@ void falco_engine::get_json_details(
filter_details details;
filter_details compiled_details;
nlohmann::json json_details;
for(const auto &m : m_rule_collector.macros())
for(const auto &m : m_rule_collector->macros())
{
details.known_macros.insert(m.name);
compiled_details.known_macros.insert(m.name);
}
for(const auto &l : m_rule_collector.lists())
for(const auto &l : m_rule_collector->lists())
{
details.known_lists.insert(l.name);
compiled_details.known_lists.insert(l.name);
@@ -958,7 +989,7 @@ bool falco_engine::check_plugin_requirements(
std::string& err) const
{
err = "";
for (const auto &alternatives : m_rule_collector.required_plugin_versions())
for(const auto &alternatives : m_rule_collector->required_plugin_versions())
{
if (!check_plugin_requirement_alternatives(plugins, alternatives, err))
{