408 lines
12 KiB
Go
408 lines
12 KiB
Go
package lib
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import (
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"bytes"
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"codeberg.org/meta/gzipped/v2"
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"crypto/rand"
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"encoding/base64"
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"encoding/hex"
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"errors"
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"fmt"
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"git.gammaspectra.live/git/go-away/embed"
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"git.gammaspectra.live/git/go-away/lib/policy"
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"github.com/google/cel-go/common/types"
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"html/template"
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"io"
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"log/slog"
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"maps"
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"net/http"
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"path"
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"path/filepath"
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"strconv"
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"strings"
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"time"
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)
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var templates map[string]*template.Template
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var cacheBust string
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// DefaultValidity TODO: adjust
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const DefaultValidity = time.Hour * 24 * 7
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func init() {
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buf := make([]byte, 16)
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_, _ = rand.Read(buf)
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cacheBust = base64.RawURLEncoding.EncodeToString(buf)
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templates = make(map[string]*template.Template)
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dir, err := embed.TemplatesFs.ReadDir("templates")
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if err != nil {
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panic(err)
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}
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for _, e := range dir {
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if e.IsDir() {
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continue
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}
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data, err := embed.TemplatesFs.ReadFile(filepath.Join("templates", e.Name()))
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if err != nil {
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panic(err)
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}
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err = initTemplate(e.Name(), string(data))
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if err != nil {
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panic(err)
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}
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}
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}
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func initTemplate(name, data string) error {
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tpl := template.New(name)
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_, err := tpl.Parse(data)
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if err != nil {
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return err
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}
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templates[name] = tpl
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return nil
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}
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func (state *State) challengePage(w http.ResponseWriter, id string, status int, challenge string, params map[string]any) error {
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input := make(map[string]any)
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input["Id"] = id
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input["Random"] = cacheBust
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input["Challenge"] = challenge
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input["Path"] = state.UrlPath
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input["Theme"] = state.Settings.ChallengeTemplateTheme
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maps.Copy(input, params)
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if _, ok := input["Title"]; !ok {
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input["Title"] = "Checking you are not a bot"
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}
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w.Header().Set("Content-Type", "text/html; charset=utf-8")
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buf := bytes.NewBuffer(make([]byte, 0, 8192))
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err := templates["challenge-"+state.Settings.ChallengeTemplate+".gohtml"].Execute(buf, input)
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if err != nil {
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_ = state.errorPage(w, id, http.StatusInternalServerError, err)
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} else {
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w.WriteHeader(status)
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_, _ = w.Write(buf.Bytes())
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}
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return nil
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}
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func (state *State) errorPage(w http.ResponseWriter, id string, status int, err error) error {
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w.Header().Set("Content-Type", "text/html; charset=utf-8")
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buf := bytes.NewBuffer(make([]byte, 0, 8192))
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err2 := templates["challenge-"+state.Settings.ChallengeTemplate+".gohtml"].Execute(buf, map[string]any{
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"Id": id,
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"Random": cacheBust,
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"Error": err.Error(),
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"Path": state.UrlPath,
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"Theme": state.Settings.ChallengeTemplateTheme,
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"Title": "Oh no! " + http.StatusText(status),
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"HideSpinner": true,
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"Challenge": "",
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})
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if err2 != nil {
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panic(err2)
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} else {
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w.WriteHeader(status)
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_, _ = w.Write(buf.Bytes())
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}
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return nil
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}
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func (state *State) addTiming(w http.ResponseWriter, name, desc string, duration time.Duration) {
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if state.Settings.Debug {
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w.Header().Add("Server-Timing", fmt.Sprintf("%s;desc=%s;dur=%d", name, strconv.Quote(desc), duration.Milliseconds()))
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}
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}
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func GetLoggerForRequest(r *http.Request) *slog.Logger {
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return slog.With(
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"request_id", r.Header.Get("X-Away-Id"),
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"remote_address", getRequestAddress(r),
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"user_agent", r.UserAgent(),
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"host", r.Host,
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"path", r.URL.Path,
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"query", r.URL.RawQuery,
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)
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}
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func (state *State) handleRequest(w http.ResponseWriter, r *http.Request) {
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host := r.Host
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backend, ok := state.Settings.Backends[host]
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if !ok {
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http.Error(w, http.StatusText(http.StatusServiceUnavailable), http.StatusServiceUnavailable)
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return
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}
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lg := GetLoggerForRequest(r)
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start := time.Now()
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//TODO better matcher! combo ast?
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env := map[string]any{
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"host": host,
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"method": r.Method,
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"remoteAddress": getRequestAddress(r),
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"userAgent": r.UserAgent(),
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"path": r.URL.Path,
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"query": func() map[string]string {
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result := make(map[string]string)
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for k, v := range r.URL.Query() {
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result[k] = strings.Join(v, ",")
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}
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return result
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}(),
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"headers": func() map[string]string {
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result := make(map[string]string)
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for k, v := range r.Header {
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result[k] = strings.Join(v, ",")
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}
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return result
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}(),
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}
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state.addTiming(w, "rule-env", "Setup the rule environment", time.Since(start))
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var (
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ruleEvalDuration time.Duration
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)
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serve := func() {
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state.addTiming(w, "rule-eval", "Evaluate access rules", ruleEvalDuration)
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backend.ServeHTTP(w, r)
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}
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fail := func(code int, err error) {
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state.addTiming(w, "rule-eval", "Evaluate access rules", ruleEvalDuration)
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_ = state.errorPage(w, r.Header.Get("X-Away-Id"), code, err)
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}
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setAwayState := func(rule RuleState) {
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r.Header.Set("X-Away-Rule", rule.Name)
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r.Header.Set("X-Away-Hash", rule.Hash)
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r.Header.Set("X-Away-Action", string(rule.Action))
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}
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for _, rule := range state.Rules {
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// skip rules that have host match
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if rule.Host != nil && *rule.Host != host {
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continue
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}
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start = time.Now()
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out, _, err := rule.Program.Eval(env)
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ruleEvalDuration += time.Since(start)
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if err != nil {
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fail(http.StatusInternalServerError, err)
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lg.Error(err.Error(), "rule", rule.Name, "rule_hash", rule.Hash)
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panic(err)
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return
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} else if out != nil && out.Type() == types.BoolType {
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if out.Equal(types.True) == types.True {
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switch rule.Action {
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default:
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panic(fmt.Errorf("unknown action %s", rule.Action))
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case policy.RuleActionPASS:
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lg.Debug("request passed", "rule", rule.Name, "rule_hash", rule.Hash)
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setAwayState(rule)
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serve()
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return
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case policy.RuleActionCHALLENGE, policy.RuleActionCHECK:
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start = time.Now()
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expiry := time.Now().UTC().Add(DefaultValidity).Round(DefaultValidity)
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for _, challengeName := range rule.Challenges {
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key := state.GetChallengeKeyForRequest(challengeName, expiry, r)
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ok, err := state.VerifyChallengeToken(challengeName, key, w, r)
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if !ok || err != nil {
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if !errors.Is(err, http.ErrNoCookie) {
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ClearCookie(CookiePrefix+challengeName, w)
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}
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} else {
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if rule.Action == policy.RuleActionCHECK {
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goto nextRule
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}
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// we passed the challenge!
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lg.Debug("request passed", "rule", rule.Name, "rule_hash", rule.Hash, "challenge", challengeName)
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setAwayState(rule)
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serve()
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return
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}
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}
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state.addTiming(w, "challenge-token-check", "Verify client challenge tokens", time.Since(start))
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// none matched, issue first challenge in priority
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for _, challengeName := range rule.Challenges {
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c := state.Challenges[challengeName]
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if c.Challenge != nil {
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result := c.Challenge(w, r, state.GetChallengeKeyForRequest(challengeName, expiry, r), expiry)
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switch result {
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case ChallengeResultStop:
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lg.Info("request challenged", "rule", rule.Name, "rule_hash", rule.Hash, "challenge", challengeName)
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return
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case ChallengeResultContinue:
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continue
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case ChallengeResultPass:
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if rule.Action == policy.RuleActionCHECK {
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goto nextRule
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}
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GetLoggerForRequest(r).Warn("challenge passed", "rule", rule.Name, "rule_hash", rule.Hash, "challenge", challengeName)
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// we pass the challenge early!
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r.Header.Set(fmt.Sprintf("X-Away-Challenge-%s-Verify", challengeName), "PASS")
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lg.Debug("request passed", "rule", rule.Name, "rule_hash", rule.Hash, "challenge", challengeName)
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setAwayState(rule)
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serve()
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return
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}
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} else {
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panic("challenge not found")
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}
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}
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case policy.RuleActionDENY:
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lg.Info("request denied", "rule", rule.Name, "rule_hash", rule.Hash)
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//TODO: config error code
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fail(http.StatusForbidden, fmt.Errorf("access denied: denied by administrative rule %s/%s", r.Header.Get("X-Away-Id"), rule.Hash))
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return
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case policy.RuleActionBLOCK:
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lg.Info("request blocked", "rule", rule.Name, "rule_hash", rule.Hash)
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//TODO: config error code
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//TODO: configure block
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fail(http.StatusForbidden, fmt.Errorf("access denied: blocked by administrative rule %s/%s", r.Header.Get("X-Away-Id"), rule.Hash))
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return
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case policy.RuleActionPOISON:
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lg.Info("request poisoned", "rule", rule.Name, "rule_hash", rule.Hash)
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mime := "text/html"
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switch path.Ext(r.URL.Path) {
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case ".css":
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case ".json", ".js", ".mjs":
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}
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encodings := strings.Split(r.Header.Get("Accept-Encoding"), ",")
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for i, encoding := range encodings {
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encodings[i] = strings.TrimSpace(strings.ToLower(encoding))
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}
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reader, encoding := state.getPoison(mime, encodings)
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if reader == nil {
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mime = "application/octet-stream"
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reader, encoding = state.getPoison(mime, encodings)
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}
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if reader != nil {
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defer reader.Close()
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}
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w.Header().Set("Cache-Control", "max-age=0, private, must-revalidate, no-transform")
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w.Header().Set("Vary", "Accept-Encoding")
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w.Header().Set("Content-Type", mime)
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w.Header().Set("X-Content-Type-Options", "nosniff")
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if encoding != "" {
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w.Header().Set("Content-Encoding", encoding)
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}
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w.WriteHeader(http.StatusOK)
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if flusher, ok := w.(http.Flusher); ok {
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// trigger chunked encoding
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flusher.Flush()
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}
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if r != nil {
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_, _ = io.Copy(w, reader)
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}
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return
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}
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}
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}
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nextRule:
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}
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serve()
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return
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}
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func (state *State) setupRoutes() error {
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state.Mux.HandleFunc("/", state.handleRequest)
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state.Mux.Handle("GET "+state.UrlPath+"/assets/", http.StripPrefix(state.UrlPath, gzipped.FileServer(gzipped.FS(embed.AssetsFs))))
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for challengeName, c := range state.Challenges {
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if c.Static != nil {
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state.Mux.Handle("GET "+c.Path+"/static/", c.Static)
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}
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if c.ChallengeScript != nil {
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state.Mux.Handle("GET "+c.ChallengeScriptPath, c.ChallengeScript)
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}
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if c.MakeChallenge != nil {
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state.Mux.Handle(fmt.Sprintf("POST %s/make-challenge", c.Path), c.MakeChallenge)
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}
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if c.VerifyChallenge != nil {
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state.Mux.Handle(fmt.Sprintf("GET %s/verify-challenge", c.Path), c.VerifyChallenge)
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} else if c.Verify != nil {
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state.Mux.HandleFunc(fmt.Sprintf("GET %s/verify-challenge", c.Path), func(w http.ResponseWriter, r *http.Request) {
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err := func() (err error) {
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expiry := time.Now().UTC().Add(DefaultValidity).Round(DefaultValidity)
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key := state.GetChallengeKeyForRequest(challengeName, expiry, r)
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result := r.FormValue("result")
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requestId, err := hex.DecodeString(r.FormValue("requestId"))
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if err == nil {
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r.Header.Set("X-Away-Id", hex.EncodeToString(requestId))
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}
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start := time.Now()
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ok, err := c.Verify(key, result)
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state.addTiming(w, "challenge-verify", "Verify client challenge", time.Since(start))
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if err != nil {
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GetLoggerForRequest(r).Error(fmt.Errorf("challenge error: %w", err).Error(), "challenge", challengeName, "redirect", r.FormValue("redirect"))
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return err
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} else if !ok {
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GetLoggerForRequest(r).Warn("challenge failed", "challenge", challengeName, "redirect", r.FormValue("redirect"))
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ClearCookie(CookiePrefix+challengeName, w)
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_ = state.errorPage(w, r.Header.Get("X-Away-Id"), http.StatusForbidden, fmt.Errorf("access denied: failed challenge %s", challengeName))
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return nil
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}
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GetLoggerForRequest(r).Info("challenge passed", "challenge", challengeName, "redirect", r.FormValue("redirect"))
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token, err := state.IssueChallengeToken(challengeName, key, []byte(result), expiry)
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if err != nil {
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ClearCookie(CookiePrefix+challengeName, w)
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} else {
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SetCookie(CookiePrefix+challengeName, token, expiry, w)
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}
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http.Redirect(w, r, r.FormValue("redirect"), http.StatusTemporaryRedirect)
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return nil
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}()
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if err != nil {
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ClearCookie(CookiePrefix+challengeName, w)
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_ = state.errorPage(w, r.Header.Get("X-Away-Id"), http.StatusInternalServerError, err)
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return
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}
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})
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}
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}
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return nil
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}
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