261 lines
7.0 KiB
Go
261 lines
7.0 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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"errors"
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"fmt"
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go_away "git.gammaspectra.live/git/go-away"
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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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"maps"
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"net/http"
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"path/filepath"
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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 := go_away.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 := go_away.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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tpl := template.New(e.Name())
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_, err = tpl.Parse(string(data))
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if err != nil {
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panic(err)
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}
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templates[e.Name()] = tpl
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}
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}
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func (state *State) challengePage(w http.ResponseWriter, status int, challenge string, params map[string]any) error {
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input := make(map[string]any)
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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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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, 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, 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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"Random": cacheBust,
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"Error": err.Error(),
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"Path": state.UrlPath,
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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) handleRequest(w http.ResponseWriter, r *http.Request) {
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//TODO better matcher! combo ast?
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env := map[string]any{
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"method": r.Method,
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"remoteAddress": state.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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for _, rule := range state.Rules {
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if out, _, err := rule.Program.Eval(env); err != nil {
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//TODO error
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panic(err)
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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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state.Backend.ServeHTTP(w, r)
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return
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case policy.RuleActionCHALLENGE, policy.RuleActionCHECK:
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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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//TODO log?
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state.Backend.ServeHTTP(w, r)
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return
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}
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}
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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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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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// we pass the challenge early!
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state.Backend.ServeHTTP(w, r)
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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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//TODO: config error code
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_ = state.errorPage(w, http.StatusForbidden, fmt.Errorf("access denied: denied by administrative rule %s", rule.Hash))
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return
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case policy.RuleActionBLOCK:
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//TODO: config error code
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//TODO: configure block
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_ = state.errorPage(w, http.StatusForbidden, fmt.Errorf("access denied: blocked by administrative rule %s", rule.Hash))
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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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state.Backend.ServeHTTP(w, r)
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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(go_away.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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if ok, err := c.Verify(key, result); err != nil {
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return err
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} else if !ok {
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ClearCookie(CookiePrefix+challengeName, w)
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_ = state.errorPage(w, http.StatusForbidden, fmt.Errorf("access denied: failed challenge %s", challengeName))
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return nil
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}
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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, 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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