Files
crowdsec-bouncer-traefik-pl…/bouncer.go
T
2022-09-28 13:39:34 +02:00

305 lines
8.0 KiB
Go

// Package plugindemo a demo plugin.
package crowdsec_bouncer_traefik_plugin
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io/ioutil"
"log"
"net"
"net/http"
"net/url"
"text/template"
"time"
ttl_map "github.com/leprosus/golang-ttl-map"
)
const (
realIpHeader = "X-Real-Ip"
forwardHeader = "X-Forwarded-For"
crowdsecAuthHeader = "X-Api-Key"
crowdsecRoute = "v1/decisions"
crowdsecStreamRoute = "v1/decisions/stream"
cacheBannedValue = "t"
cacheNoBannedValue = "f"
)
// var ipRegex = regexp.MustCompile(`\b\d+\.\d+\.\d+\.\d+\b`)
var cache = ttl_map.New()
type Config struct {
Enabled bool `json:"enabled,omitempty"`
CrowdsecMode string `json:"crowdsecMode,omitempty"`
CrowdsecLapiScheme string `json:"crowdsecLapiScheme,omitempty"`
CrowdsecLapiHost string `json:"crowdsecLapiHost,omitempty"`
CrowdsecLapiKey string `json:"crowdsecLapiKey,omitempty"`
UpdateIntervalSeconds int64 `json:"updateIntervalSeconds,omitempty"`
DefaultDecisionSeconds int64 `json:"defaultDecisionSeconds,omitempty"`
}
func CreateConfig() *Config {
return &Config{
Enabled: false,
CrowdsecMode: "stream",
CrowdsecLapiScheme: "http",
CrowdsecLapiHost: "crowdsec:8080",
CrowdsecLapiKey: "",
UpdateIntervalSeconds: 10,
DefaultDecisionSeconds: 10,
}
}
type Bouncer struct {
next http.Handler
name string
template *template.Template
enabled bool
crowdsecStreamHealthy bool
crowdsecScheme string
crowdsecHost string
crowdsecKey string
crowdsecMode string
updateInterval int64
defaultDecisionTimeout int64
client *http.Client
}
// New created a new Demo plugin.
func New(ctx context.Context, next http.Handler, config *Config, name string) (http.Handler, error) {
required := map[string]string{
"CrowdsecLapiScheme": config.CrowdsecLapiScheme,
"CrowdsecLapiHost": config.CrowdsecLapiHost,
"CrowdsecLapiKey": config.CrowdsecLapiKey,
"CrowdsecMode": config.CrowdsecMode,
}
for val, key := range required {
if len(val) == 0 {
return nil, fmt.Errorf("%v cannot be empty", key)
}
}
if !contains([]string{"none", "live", "stream"}, config.CrowdsecMode) {
return nil, fmt.Errorf("CrowdsecMode must be one of: none, live or stream")
}
if !contains([]string{"http", "https"}, config.CrowdsecLapiScheme) {
return nil, fmt.Errorf("CrowdsecLapiScheme must be one of: http, https")
}
testUrl := url.URL{
Scheme: config.CrowdsecLapiScheme,
Host: config.CrowdsecLapiHost,
Path: crowdsecRoute,
}
_, err := http.NewRequest(http.MethodGet, testUrl.String(), nil)
if err != nil {
return nil, fmt.Errorf("CrowdsecLapiScheme://CrowdsecLapiHost: '%v://%v' must be an URL", config.CrowdsecLapiScheme, config.CrowdsecLapiHost)
}
bouncer := &Bouncer{
next: next,
name: name,
template: template.New("CrowdsecBouncer").Delims("[[", "]]"),
enabled: config.Enabled,
crowdsecStreamHealthy: false,
crowdsecMode: config.CrowdsecMode,
crowdsecScheme: config.CrowdsecLapiScheme,
crowdsecHost: config.CrowdsecLapiHost,
crowdsecKey: config.CrowdsecLapiKey,
updateInterval: config.UpdateIntervalSeconds,
defaultDecisionTimeout: config.DefaultDecisionSeconds,
client: &http.Client{
Transport: &http.Transport{
MaxIdleConns: 10,
IdleConnTimeout: 30 * time.Second,
},
Timeout: 5 * time.Second,
},
}
go handleStreamCache(bouncer, "true")
return bouncer, nil
}
func (a *Bouncer) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
if !a.enabled {
log.Printf("not enabled")
a.next.ServeHTTP(rw, req)
return
}
remoteHost, _, err := net.SplitHostPort(req.RemoteAddr)
if err != nil {
log.Printf("failed to extract ip from remote address: %v", err)
a.next.ServeHTTP(rw, req)
return
}
if a.crowdsecMode == "stream" || a.crowdsecMode == "live" {
isBanned, err := getDecision(remoteHost)
if err == nil {
if isBanned {
rw.WriteHeader(http.StatusForbidden)
} else {
a.next.ServeHTTP(rw, req)
}
return
}
}
if a.crowdsecMode == "stream" {
a.next.ServeHTTP(rw, req)
return
}
if a.crowdsecMode == "none" || a.crowdsecMode == "live" {
noneUrl := url.URL{
Scheme: a.crowdsecScheme,
Host: a.crowdsecHost,
Path: crowdsecRoute,
RawQuery: fmt.Sprintf("ip=%v&banned=true", remoteHost),
}
req, _ := http.NewRequest(http.MethodGet, noneUrl.String(), nil)
req.Header.Add(crowdsecAuthHeader, a.crowdsecKey)
res, err := a.client.Do(req)
if err != nil {
log.Printf("failed to get decision: %s", err)
rw.WriteHeader(http.StatusForbidden)
return
}
defer res.Body.Close()
if res.StatusCode != 200 {
log.Printf("failed to get decision, status code: %d", res.StatusCode)
rw.WriteHeader(http.StatusForbidden)
return
}
body, err := ioutil.ReadAll(res.Body)
if err != nil {
log.Printf("failed to read body: %s", err)
rw.WriteHeader(http.StatusForbidden)
return
}
if !bytes.Equal(body, []byte("null")) {
var decisions []Decision
err = json.Unmarshal(body, &decisions)
if err != nil {
log.Printf("failed to parse body: %s", err)
rw.WriteHeader(http.StatusForbidden)
return
}
if len(decisions) == 0 {
if a.crowdsecMode == "live" {
setDecision(remoteHost, false, a.defaultDecisionTimeout)
}
a.next.ServeHTTP(rw, req)
return
}
duration, err := time.ParseDuration(decisions[0].Duration)
if err != nil {
log.Printf("failed to parse duration: %s", err)
rw.WriteHeader(http.StatusForbidden)
return
}
log.Printf("ip banned: %v", remoteHost)
rw.WriteHeader(http.StatusForbidden)
setDecision(remoteHost, true, int64(duration.Seconds()))
return
}
if a.crowdsecMode == "live" {
setDecision(remoteHost, false, a.defaultDecisionTimeout)
}
a.next.ServeHTTP(rw, req)
return
}
a.next.ServeHTTP(rw, req)
}
// CUSTOM CODE
type Decision struct {
Id int `json:"id"`
Origin string `json:"origin"`
Type string `json:"type"`
Scope string `json:"scope"`
Value string `json:"value"`
Duration string `json:"duration"`
Scenario string `json:"scenario"`
Simulated bool `json:"simulated"`
}
type Stream struct {
Deleted []Decision `json:"deleted"`
New []Decision `json:"new"`
}
func contains(source []string, target string) bool {
for _, a := range source {
if a == target {
return true
}
}
return false
}
func getDecision(clientIP string) (bool, error) {
isBanned, ok := cache.Get(clientIP)
if ok && len(isBanned.(string)) > 0 {
if isBanned == cacheNoBannedValue {
return false, nil
} else {
return true, nil
}
}
return false, fmt.Errorf("no data")
}
func setDecision(clientIP string, isBanned bool, duration int64) {
if isBanned {
cache.Set(clientIP, cacheBannedValue, duration)
} else {
cache.Set(clientIP, cacheNoBannedValue, duration)
}
}
func handleStreamCache(a *Bouncer, initialized string) {
time.AfterFunc(time.Duration(a.updateInterval) * time.Second, func () {
handleStreamCache(a, "false")
})
streamUrl := url.URL{
Scheme: a.crowdsecScheme,
Host: a.crowdsecHost,
Path: crowdsecStreamRoute,
RawQuery: fmt.Sprintf("startup=%s", initialized),
}
req, _ := http.NewRequest(http.MethodGet, streamUrl.String(), nil)
req.Header.Add(crowdsecAuthHeader, a.crowdsecKey)
res, err := a.client.Do(req)
if err != nil || res.StatusCode == http.StatusForbidden {
a.crowdsecStreamHealthy = false
return
}
defer res.Body.Close()
body, err := ioutil.ReadAll(res.Body)
if err != nil {
a.crowdsecStreamHealthy = false
return
}
var stream Stream
err = json.Unmarshal(body, &stream)
if err != nil {
a.crowdsecStreamHealthy = false
return
}
for _, decision := range stream.New {
duration, err := time.ParseDuration(decision.Duration)
if err == nil {
setDecision(decision.Value, true, int64(duration.Seconds()))
}
}
for _, decision := range stream.Deleted {
cache.Del(decision.Value)
}
a.crowdsecStreamHealthy = true
}