mirror of
https://github.com/maxlerebourg/crowdsec-bouncer-traefik-plugin.git
synced 2026-07-21 11:38:59 +02:00
347 lines
10 KiB
Go
347 lines
10 KiB
Go
package crowdsec_bouncer_traefik_plugin
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import (
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"bytes"
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"context"
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"encoding/json"
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"net"
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"net/http"
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"net/url"
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"text/template"
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"time"
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ttl_map "github.com/leprosus/golang-ttl-map"
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)
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const (
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crowdsecAuthHeader = "X-Api-Key"
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crowdsecRoute = "v1/decisions"
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crowdsecStreamRoute = "v1/decisions/stream"
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cacheBannedValue = "t"
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cacheNoBannedValue = "f"
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)
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var cache = ttl_map.New()
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// Config the plugin configuration.
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type Config struct {
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Enabled bool `json:"enabled,omitempty"`
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CrowdsecMode string `json:"crowdsecMode,omitempty"`
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CrowdsecLapiScheme string `json:"crowdsecLapiScheme,omitempty"`
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CrowdsecLapiHost string `json:"crowdsecLapiHost,omitempty"`
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CrowdsecLapiKey string `json:"crowdsecLapiKey,omitempty"`
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UpdateIntervalSeconds int64 `json:"updateIntervalSeconds,omitempty"`
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DefaultDecisionSeconds int64 `json:"defaultDecisionSeconds,omitempty"`
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}
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// CreateConfig creates the default plugin configuration.
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func CreateConfig() *Config {
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return &Config{
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Enabled: false,
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CrowdsecMode: "stream",
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CrowdsecLapiScheme: "http",
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CrowdsecLapiHost: "crowdsec:8080",
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CrowdsecLapiKey: "",
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UpdateIntervalSeconds: 60,
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DefaultDecisionSeconds: 60,
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}
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}
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// Bouncer a Bouncer plugin.
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type Bouncer struct {
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next http.Handler
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name string
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template *template.Template
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enabled bool
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crowdsecStreamHealthy bool
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crowdsecScheme string
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crowdsecHost string
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crowdsecKey string
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crowdsecMode string
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updateInterval int64
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defaultDecisionTimeout int64
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client *http.Client
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}
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// New creates the crowdsec bouncer plugin.
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func New(ctx context.Context, next http.Handler, config *Config, name string) (http.Handler, error) {
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requiredStrings := map[string]string{
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"CrowdsecLapiScheme": config.CrowdsecLapiScheme,
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"CrowdsecLapiHost": config.CrowdsecLapiHost,
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"CrowdsecLapiKey": config.CrowdsecLapiKey,
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"CrowdsecMode": config.CrowdsecMode,
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}
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for key, val := range requiredStrings {
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if len(val) == 0 {
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return nil, fmt.Errorf("%v cannot be empty", key)
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}
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}
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requiredInt := map[string]int64{
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"UpdateIntervalSeconds": config.UpdateIntervalSeconds,
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"DefaultDecisionSeconds": config.DefaultDecisionSeconds,
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}
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for key, val := range requiredInt {
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if val < 1 {
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return nil, fmt.Errorf("%v cannot be less than 1", key)
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}
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}
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// none -> If the client IP is on ban list, it will get a http code 403 response.
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// Otherwise, request will continue as usual. All request call the Crowdsec LAPI
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// live -> If the client IP is on ban list, it will get a http code 403 response.
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// Otherwise, request will continue as usual.
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// The bouncer can leverage use of a local cache in order to reduce the number
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// of requests made to the Crowdsec LAPI. It will keep in cache the status for
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// each IP that makes queries.
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// stream -> Stream Streaming mode allows you to keep in the local cache only the Banned IPs,
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// every requests that does not hit the cache is authorized.
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// Every minute, the cache is updated with news from the Crowdsec LAPI.
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if !contains([]string{"none", "live", "stream"}, config.CrowdsecMode) {
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return nil, fmt.Errorf("CrowdsecMode must be one of: none, live or stream")
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}
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if !contains([]string{"http", "https"}, config.CrowdsecLapiScheme) {
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return nil, fmt.Errorf("CrowdsecLapiScheme must be one of: http, https")
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}
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testURL := url.URL{
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Scheme: config.CrowdsecLapiScheme,
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Host: config.CrowdsecLapiHost,
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Path: crowdsecRoute,
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}
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_, err := http.NewRequest(http.MethodGet, testURL.String(), nil)
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if err != nil {
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return nil, fmt.Errorf("CrowdsecLapiScheme://CrowdsecLapiHost: '%v://%v' must be an URL", config.CrowdsecLapiScheme, config.CrowdsecLapiHost)
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}
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bouncer := &Bouncer{
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next: next,
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name: name,
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template: template.New("CrowdsecBouncer").Delims("[[", "]]"),
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enabled: config.Enabled,
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crowdsecStreamHealthy: false,
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crowdsecMode: config.CrowdsecMode,
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crowdsecScheme: config.CrowdsecLapiScheme,
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crowdsecHost: config.CrowdsecLapiHost,
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crowdsecKey: config.CrowdsecLapiKey,
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updateInterval: config.UpdateIntervalSeconds,
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defaultDecisionTimeout: config.DefaultDecisionSeconds,
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client: &http.Client{
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Transport: &http.Transport{
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MaxIdleConns: 10,
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IdleConnTimeout: 30 * time.Second,
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},
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Timeout: 5 * time.Second,
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},
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}
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// if we are on a stream mode, we fetch in a go routine every minute the new decisions.
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if config.CrowdsecMode == "stream" {
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go handleStreamCache(bouncer, true)
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}
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return bouncer, nil
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}
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// TODO the serve HTTP should be split as it's too long.
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// ServeHTTP principal function of plugin.
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func (a *Bouncer) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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if !a.enabled {
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log.Printf("Crowdsec Bouncer not enabled")
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a.next.ServeHTTP(rw, req)
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return
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}
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// TODO Make sur remote address does not include the port.
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remoteHost, _, err := net.SplitHostPort(req.RemoteAddr)
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if err != nil {
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log.Printf("failed to extract ip from remote address: %v", err)
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a.next.ServeHTTP(rw, req)
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return
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}
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if a.crowdsecMode == "stream" || a.crowdsecMode == "live" {
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isBanned, err := getDecision(remoteHost)
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if err == nil {
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if isBanned {
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rw.WriteHeader(http.StatusForbidden)
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} else {
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a.next.ServeHTTP(rw, req)
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}
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return
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}
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}
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// Right here if we cannot join the stream we forbid the request to go on.
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if a.crowdsecMode == "stream" {
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if a.crowdsecStreamHealthy {
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a.next.ServeHTTP(rw, req)
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} else {
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rw.WriteHeader(http.StatusForbidden)
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}
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return
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}
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// We are now in none or live mode.
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noneURL := url.URL{
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Scheme: a.crowdsecScheme,
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Host: a.crowdsecHost,
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Path: crowdsecRoute,
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RawQuery: fmt.Sprintf("ip=%v&banned=true", remoteHost),
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}
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request, _ := http.NewRequest(http.MethodGet, noneURL.String(), nil)
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request.Header.Add(crowdsecAuthHeader, a.crowdsecKey)
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res, err := a.client.Do(request)
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if err != nil {
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log.Printf("failed to get decision: %s", err)
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rw.WriteHeader(http.StatusForbidden)
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return
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}
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defer closeBody(res.Body)
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if res.StatusCode != 200 {
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log.Printf("failed to get decision, status code: %d", res.StatusCode)
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rw.WriteHeader(http.StatusForbidden)
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return
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}
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body, err := ioutil.ReadAll(res.Body)
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if err != nil {
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log.Printf("failed to read body: %s", err)
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rw.WriteHeader(http.StatusForbidden)
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return
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}
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if !bytes.Equal(body, []byte("null")) {
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var decisions []Decision
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err = json.Unmarshal(body, &decisions)
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if err != nil {
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log.Printf("failed to parse body: %s", err)
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rw.WriteHeader(http.StatusForbidden)
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return
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}
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if len(decisions) == 0 {
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if a.crowdsecMode == "live" {
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setDecision(remoteHost, false, a.defaultDecisionTimeout)
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}
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a.next.ServeHTTP(rw, req)
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return
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}
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duration, err := time.ParseDuration(decisions[0].Duration)
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if err != nil {
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log.Printf("failed to parse duration: %s", err)
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rw.WriteHeader(http.StatusForbidden)
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return
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}
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rw.WriteHeader(http.StatusForbidden)
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setDecision(remoteHost, true, int64(duration.Seconds()))
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return
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}
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if a.crowdsecMode == "live" {
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setDecision(remoteHost, false, a.defaultDecisionTimeout)
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}
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a.next.ServeHTTP(rw, req)
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}
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// CUSTOM CODE.
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// TODO place in another file.
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// Decision Body returned from Crowdsec LAPI.
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type Decision struct {
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ID int `json:"id"`
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Origin string `json:"origin"`
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Type string `json:"type"`
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Scope string `json:"scope"`
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Value string `json:"value"`
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Duration string `json:"duration"`
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Scenario string `json:"scenario"`
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Simulated bool `json:"simulated"`
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}
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// Stream Body returned from Crowdsec Stream LAPI.
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type Stream struct {
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Deleted []Decision `json:"deleted"`
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New []Decision `json:"new"`
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}
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func contains(source []string, target string) bool {
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for _, a := range source {
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if a == target {
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return true
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}
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}
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return false
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}
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// Get Decision check in the cache if the IP has the banned / not banned value.
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// Otherwise return with an error to add the IP in cache if we are on.
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func getDecision(clientIP string) (bool, error) {
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isBanned, ok := cache.Get(clientIP)
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if ok && len(isBanned.(string)) > 0 {
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return isBanned == cacheNoBannedValue, nil
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}
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return false, fmt.Errorf("no data")
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}
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func setDecision(clientIP string, isBanned bool, duration int64) {
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if isBanned {
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cache.Set(clientIP, cacheBannedValue, duration)
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} else {
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cache.Set(clientIP, cacheNoBannedValue, duration)
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}
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}
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func handleStreamCache(a *Bouncer, initialized bool) {
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// TODO clean properly on exit.
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time.AfterFunc(time.Duration(a.updateInterval)*time.Second, func() {
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handleStreamCache(a, false)
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})
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streamURL := url.URL{
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Scheme: a.crowdsecScheme,
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Host: a.crowdsecHost,
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Path: crowdsecStreamRoute,
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RawQuery: fmt.Sprintf("startup=%t", initialized),
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}
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req, _ := http.NewRequest(http.MethodGet, streamURL.String(), nil)
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req.Header.Add(crowdsecAuthHeader, a.crowdsecKey)
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res, err := a.client.Do(req)
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if err != nil {
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log.Printf("error while fetching decisions: %s", err)
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a.crowdsecStreamHealthy = false
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return
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}
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if res.StatusCode == http.StatusForbidden {
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log.Printf("error while fetching decisions, status code: %d", res.StatusCode)
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a.crowdsecStreamHealthy = false
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return
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}
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defer closeBody(res.Body)
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body, err := ioutil.ReadAll(res.Body)
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if err != nil {
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log.Printf("error while reading body: %s", err)
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a.crowdsecStreamHealthy = false
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return
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}
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var stream Stream
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err = json.Unmarshal(body, &stream)
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if err != nil {
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log.Printf("error while parsing body: %s", err)
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a.crowdsecStreamHealthy = false
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return
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}
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for _, decision := range stream.New {
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duration, err := time.ParseDuration(decision.Duration)
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if err == nil {
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setDecision(decision.Value, true, int64(duration.Seconds()))
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}
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}
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for _, decision := range stream.Deleted {
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cache.Del(decision.Value)
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}
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a.crowdsecStreamHealthy = true
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}
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func closeBody(Body io.ReadCloser) {
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err := Body.Close()
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if err != nil {
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log.Printf("failed to close body reader: %s", err)
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}
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} |