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rules_manager.go
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rules_manager.go
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/*
* This file is part of caronte (https://github.com/eciavatta/caronte).
* Copyright (c) 2020 Emiliano Ciavatta.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 3.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package main
import (
"context"
"errors"
"fmt"
"sort"
"strings"
"sync"
"time"
"github.com/flier/gohs/hyperscan"
"github.com/go-playground/validator/v10"
log "github.com/sirupsen/logrus"
)
const DirectionBoth = 0
const DirectionToServer = 1
const DirectionToClient = 2
type RegexFlags struct {
Caseless bool `json:"caseless" bson:"caseless,omitempty"` // Set case-insensitive matching.
DotAll bool `json:"dot_all" bson:"dot_all,omitempty"` // Matching a `.` will not exclude newlines.
MultiLine bool `json:"multi_line" bson:"multi_line,omitempty"` // Set multi-line anchoring.
Utf8Mode bool `json:"utf_8_mode" bson:"utf_8_mode,omitempty"` // Enable UTF-8 mode for this expression.
UnicodeProperty bool `json:"unicode_property" bson:"unicode_property,omitempty"` // Enable Unicode property support for this expression
}
type Pattern struct {
Regex string `json:"regex" binding:"required,min=1" bson:"regex"`
Flags RegexFlags `json:"flags" bson:"flags,omitempty"`
MinOccurrences uint `json:"min_occurrences" bson:"min_occurrences,omitempty"`
MaxOccurrences uint `json:"max_occurrences" binding:"omitempty,gtefield=MinOccurrences" bson:"max_occurrences,omitempty"`
Direction uint8 `json:"direction" binding:"omitempty,max=2" bson:"direction,omitempty"`
internalID uint
}
type Filter struct {
ServicePort uint16 `json:"service_port" bson:"service_port,omitempty"`
ClientAddress string `json:"client_address" binding:"omitempty,ip" bson:"client_address,omitempty"`
ClientPort uint16 `json:"client_port" bson:"client_port,omitempty"`
MinDuration uint `json:"min_duration" bson:"min_duration,omitempty"`
MaxDuration uint `json:"max_duration" binding:"omitempty,gtefield=MinDuration" bson:"max_duration,omitempty"`
MinBytes uint `json:"min_bytes" bson:"min_bytes,omitempty"`
MaxBytes uint `json:"max_bytes" binding:"omitempty,gtefield=MinBytes" bson:"max_bytes,omitempty"`
}
type Rule struct {
ID RowID `json:"id" bson:"_id,omitempty"`
Name string `json:"name" binding:"min=3" bson:"name"`
Color string `json:"color" binding:"hexcolor" bson:"color"`
Notes string `json:"notes" bson:"notes,omitempty"`
Enabled bool `json:"enabled" bson:"enabled"`
Patterns []Pattern `json:"patterns" bson:"patterns"`
Filter Filter `json:"filter" bson:"filter,omitempty"`
Version int64 `json:"version" bson:"version"`
}
type RulesDatabase struct {
database hyperscan.StreamDatabase
databaseSize int
version RowID
}
type RulesManager interface {
AddRule(context context.Context, rule Rule) (RowID, error)
GetRule(id RowID) (Rule, bool)
UpdateRule(context context.Context, id RowID, rule Rule) (bool, error)
GetRules() []Rule
FillWithMatchedRules(connection *Connection, clientMatches map[uint][]PatternSlice, serverMatches map[uint][]PatternSlice)
DatabaseUpdateChannel() chan RulesDatabase
}
type rulesManagerImpl struct {
storage Storage
rules map[RowID]Rule
rulesByName map[string]Rule
patterns []*hyperscan.Pattern
patternsIds map[string]uint
mutex sync.Mutex
databaseUpdated chan RulesDatabase
validate *validator.Validate
}
func LoadRulesManager(storage Storage, flagRegex string) (RulesManager, error) {
var rules []Rule
if err := storage.Find(Rules).Sort("_id", true).All(&rules); err != nil {
return nil, err
}
rulesManager := rulesManagerImpl{
storage: storage,
rules: make(map[RowID]Rule),
rulesByName: make(map[string]Rule),
patterns: make([]*hyperscan.Pattern, 0),
patternsIds: make(map[string]uint),
mutex: sync.Mutex{},
databaseUpdated: make(chan RulesDatabase, 1),
validate: validator.New(),
}
for _, rule := range rules {
if err := rulesManager.validateAndAddRuleLocal(&rule); err != nil {
return nil, err
}
}
// if there are no rules in database (e.g. first run), set flagRegex as first rule
if len(rulesManager.rules) == 0 {
_, _ = rulesManager.AddRule(context.Background(), Rule{
Name: "flag_out",
Color: "#e53935",
Notes: "Mark connections where the flags are stolen",
Patterns: []Pattern{
{Regex: flagRegex, Direction: DirectionToClient, Flags: RegexFlags{Utf8Mode: true}},
},
})
_, _ = rulesManager.AddRule(context.Background(), Rule{
Name: "flag_in",
Color: "#43A047",
Notes: "Mark connections where the flags are placed",
Patterns: []Pattern{
{Regex: flagRegex, Direction: DirectionToServer, Flags: RegexFlags{Utf8Mode: true}},
},
})
} else {
if err := rulesManager.generateDatabase(rules[len(rules)-1].ID); err != nil {
return nil, err
}
}
return &rulesManager, nil
}
func (rm *rulesManagerImpl) AddRule(context context.Context, rule Rule) (RowID, error) {
rm.mutex.Lock()
rule.ID = CustomRowID(uint64(len(rm.rules)), time.Now())
rule.Enabled = true
if err := rm.validateAndAddRuleLocal(&rule); err != nil {
rm.mutex.Unlock()
return EmptyRowID(), err
}
if err := rm.generateDatabase(rule.ID); err != nil {
rm.mutex.Unlock()
log.WithError(err).WithField("rule", rule).Panic("failed to generate database")
}
rm.mutex.Unlock()
if _, err := rm.storage.Insert(Rules).Context(context).One(rule); err != nil {
log.WithError(err).WithField("rule", rule).Panic("failed to insert rule on database")
}
return rule.ID, nil
}
func (rm *rulesManagerImpl) GetRule(id RowID) (Rule, bool) {
rule, isPresent := rm.rules[id]
return rule, isPresent
}
func (rm *rulesManagerImpl) UpdateRule(context context.Context, id RowID, rule Rule) (bool, error) {
newRule, isPresent := rm.rules[id]
if !isPresent {
return false, nil
}
sameName, isPresent := rm.rulesByName[rule.Name]
if isPresent && sameName.ID != id {
return false, errors.New("already exists another rule with the same name")
}
updated, err := rm.storage.Update(Rules).Context(context).Filter(OrderedDocument{{"_id", id}}).
One(UnorderedDocument{"name": rule.Name, "color": rule.Color})
if err != nil {
log.WithError(err).WithField("rule", rule).Panic("failed to update rule on database")
}
if updated {
rm.mutex.Lock()
newRule.Name = rule.Name
newRule.Color = rule.Color
delete(rm.rulesByName, newRule.Name)
rm.rulesByName[newRule.Name] = newRule
rm.rules[id] = newRule
rm.mutex.Unlock()
}
return updated, nil
}
func (rm *rulesManagerImpl) GetRules() []Rule {
rules := make([]Rule, 0, len(rm.rules))
for _, rule := range rm.rules {
rules = append(rules, rule)
}
sort.Slice(rules, func(i, j int) bool {
return rules[i].ID.Timestamp().Before(rules[j].ID.Timestamp())
})
return rules
}
func (rm *rulesManagerImpl) FillWithMatchedRules(connection *Connection, clientMatches map[uint][]PatternSlice,
serverMatches map[uint][]PatternSlice) {
rm.mutex.Lock()
filterFunctions := []func(rule Rule) bool{
func(rule Rule) bool {
return rule.Filter.ClientAddress == "" || connection.SourceIP == rule.Filter.ClientAddress
},
func(rule Rule) bool {
return rule.Filter.ClientPort == 0 || connection.SourcePort == rule.Filter.ClientPort
},
func(rule Rule) bool {
return rule.Filter.ServicePort == 0 || connection.DestinationPort == rule.Filter.ServicePort
},
func(rule Rule) bool {
return rule.Filter.MinDuration == 0 || uint(connection.ClosedAt.Sub(connection.StartedAt).Milliseconds()) >=
rule.Filter.MinDuration
},
func(rule Rule) bool {
return rule.Filter.MaxDuration == 0 || uint(connection.ClosedAt.Sub(connection.StartedAt).Milliseconds()) <=
rule.Filter.MaxDuration
},
func(rule Rule) bool {
return rule.Filter.MinBytes == 0 || uint(connection.ClientBytes+connection.ServerBytes) >=
rule.Filter.MinBytes
},
func(rule Rule) bool {
return rule.Filter.MaxBytes == 0 || uint(connection.ClientBytes+connection.ServerBytes) <=
rule.Filter.MinBytes
},
}
connection.MatchedRules = make([]RowID, 0)
for _, rule := range rm.rules {
matching := true
for _, f := range filterFunctions {
if !f(rule) {
matching = false
break
}
}
for _, p := range rule.Patterns {
checkOccurrences := func(occurrences []PatternSlice) bool {
return (p.MinOccurrences == 0 || uint(len(occurrences)) >= p.MinOccurrences) &&
(p.MaxOccurrences == 0 || uint(len(occurrences)) <= p.MaxOccurrences)
}
clientOccurrences, clientPresent := clientMatches[p.internalID]
serverOccurrences, serverPresent := serverMatches[p.internalID]
if p.Direction == DirectionToServer {
if !clientPresent || !checkOccurrences(clientOccurrences) {
matching = false
break
}
} else if p.Direction == DirectionToClient {
if !serverPresent || !checkOccurrences(serverOccurrences) {
matching = false
break
}
} else {
if !(clientPresent || serverPresent) || !checkOccurrences(append(clientOccurrences, serverOccurrences...)) {
matching = false
break
}
}
}
if matching {
connection.MatchedRules = append(connection.MatchedRules, rule.ID)
}
}
rm.mutex.Unlock()
}
func (rm *rulesManagerImpl) DatabaseUpdateChannel() chan RulesDatabase {
return rm.databaseUpdated
}
func (rm *rulesManagerImpl) validateAndAddRuleLocal(rule *Rule) error {
if _, alreadyPresent := rm.rulesByName[rule.Name]; alreadyPresent {
return errors.New("rule name must be unique")
}
newPatterns := make([]*hyperscan.Pattern, 0, len(rule.Patterns))
duplicatePatterns := make(map[string]bool)
for i, pattern := range rule.Patterns {
if err := rm.validate.Struct(pattern); err != nil {
return err
}
regex := pattern.Regex
if !strings.HasPrefix(regex, "/") {
regex = fmt.Sprintf("/%s", regex)
}
if !strings.HasSuffix(regex, "/") {
regex = fmt.Sprintf("%s/", regex)
}
rule.Patterns[i].Regex = regex
compiledPattern, err := pattern.BuildPattern()
if err != nil {
return err
}
regex = compiledPattern.String()
if _, isPresent := duplicatePatterns[regex]; isPresent {
return errors.New("duplicate pattern")
}
if existingPattern, isPresent := rm.patternsIds[regex]; isPresent {
rule.Patterns[i].internalID = existingPattern
continue
}
id := len(rm.patternsIds) + len(newPatterns)
rule.Patterns[i].internalID = uint(id)
compiledPattern.Id = id
newPatterns = append(newPatterns, compiledPattern)
duplicatePatterns[regex] = true
}
startID := len(rm.patterns)
for id, pattern := range newPatterns {
rm.patterns = append(rm.patterns, pattern)
regex := pattern.String()
rm.patternsIds[regex[strings.IndexByte(regex, ':')+1:]] = uint(startID + id)
}
rm.rules[rule.ID] = *rule
rm.rulesByName[rule.Name] = *rule
return nil
}
func (rm *rulesManagerImpl) generateDatabase(version RowID) error {
database, err := hyperscan.NewStreamDatabase(rm.patterns...)
if err != nil {
return err
}
go func() {
rm.databaseUpdated <- RulesDatabase{
database: database,
databaseSize: len(rm.patterns),
version: version,
}
}()
return nil
}
func (p *Pattern) BuildPattern() (*hyperscan.Pattern, error) {
hp, err := hyperscan.ParsePattern(p.Regex)
if err != nil {
return nil, err
}
hp.Flags |= hyperscan.SomLeftMost
if p.Flags.Caseless {
hp.Flags |= hyperscan.Caseless
}
if p.Flags.DotAll {
hp.Flags |= hyperscan.DotAll
}
if p.Flags.MultiLine {
hp.Flags |= hyperscan.MultiLine
}
if p.Flags.Utf8Mode {
hp.Flags |= hyperscan.Utf8Mode
}
if p.Flags.UnicodeProperty {
hp.Flags |= hyperscan.UnicodeProperty
}
if !hp.IsValid() {
return nil, errors.New("can't validate the pattern")
}
return hp, nil
}