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hydra_oidc_poc/cmd/app/main.go
2020-12-31 10:22:56 +01:00

372 lines
10 KiB
Go

package main
import (
"bytes"
"context"
"crypto/rand"
"encoding/base64"
"encoding/json"
"html/template"
"net/http"
"net/url"
"os"
"strings"
"github.com/go-openapi/runtime/client"
"github.com/gorilla/sessions"
"github.com/knadh/koanf"
jsonParser "github.com/knadh/koanf/parsers/json"
"github.com/knadh/koanf/providers/confmap"
"github.com/knadh/koanf/providers/env"
"github.com/knadh/koanf/providers/file"
"github.com/lestrrat-go/jwx/jwk"
"github.com/lestrrat-go/jwx/jwt"
log "github.com/sirupsen/logrus"
"golang.org/x/oauth2"
)
type OpenIDConfiguration struct {
AuthorizationEndpoint string `json:"authorization_endpoint"`
TokenEndpoint string `json:"token_endpoint"`
JwksUri string `json:"jwks_uri"`
EndSessionEndpoint string `json:"end_session_endpoint"`
}
var (
sessionStore *sessions.FilesystemStore
k = koanf.New(".")
)
const (
sessionKeyAccessToken = iota
sessionKeyRefreshToken
sessionKeyIdToken
sessionKeyUserId
sessionKeyRoles
sessionKeyEmail
sessionKeyUsername
sessionRedirectTarget
)
func main() {
if err := k.Load(file.Provider("resourceapp.json"), jsonParser.Parser()); err != nil && !os.IsNotExist(err) {
log.Fatalf("error loading config: %v", err)
}
const prefix = "RESOURCEAPP_"
if err := k.Load(env.Provider(prefix, ".", func(s string) string {
return strings.Replace(strings.ToLower(
strings.TrimPrefix(s, prefix)), "_", ".", -1)
}), nil); err != nil {
log.Fatalf("error loading config: %v", err)
}
oidcServer := k.MustString("oidc.server")
oidcClientId := k.MustString("oidc.client-id")
oidcClientSecret := k.MustString("oidc.client-secret")
sessionPath := k.MustString("session.path")
sessionAuthKey, err := base64.StdEncoding.DecodeString(k.String("session.auth-key"))
if err != nil {
log.Fatalf("could not decode session auth key: %s", err)
}
sessionEncKey, err := base64.StdEncoding.DecodeString(k.String("session.enc-key"))
if err != nil {
log.Fatalf("could not decode session encryption key: %s", err)
}
generated := false
if len(sessionAuthKey) != 64 {
sessionAuthKey = generateKey(64)
generated = true
}
if len(sessionEncKey) != 32 {
sessionEncKey = generateKey(32)
generated = true
}
if generated {
_ = k.Load(confmap.Provider(map[string]interface{}{
"session.auth-key": sessionAuthKey,
"session.enc-key": sessionEncKey,
}, "."), nil)
jsonData, err := k.Marshal(jsonParser.Parser())
if err != nil {
log.Fatalf("could not encode session config")
}
log.Infof("put the following in your resourceapp.json:\n%s", string(jsonData))
}
var discoveryResponse OpenIDConfiguration
var discoveryUrl *url.URL
if discoveryUrl, err = url.Parse(oidcServer); err != nil {
log.Fatalf("could not parse oidc.server parameter value %s: %s", oidcServer, err)
} else {
discoveryUrl.Path = "/.well-known/openid-configuration"
}
apiClient, err := client.TLSClient(client.TLSClientOptions{InsecureSkipVerify: true})
if err := discoverOidc(discoveryUrl, apiClient, &discoveryResponse); err != nil {
log.Fatalf("OpenID Connect discovery failed: %s", err)
}
oauth2Config := &oauth2.Config{
ClientID: oidcClientId,
ClientSecret: oidcClientSecret,
Endpoint: oauth2.Endpoint{
AuthURL: discoveryResponse.AuthorizationEndpoint,
TokenURL: discoveryResponse.TokenEndpoint,
},
Scopes: []string{"openid", "offline"},
}
keySet, err := jwk.FetchHTTP(discoveryResponse.JwksUri, jwk.WithHTTPClient(apiClient))
if err != nil {
log.Fatalf("could not fetch JWKs: %s", err)
}
if _, err = os.Stat(sessionPath); err != nil {
if os.IsNotExist(err) {
if err = os.MkdirAll(sessionPath, 0700); err != nil {
log.Fatalf("could not create session store directory: %s", err)
}
}
}
sessionStore = sessions.NewFilesystemStore(sessionPath, sessionAuthKey, sessionEncKey)
http.Handle("/", authenticate(oauth2Config)(NewIndexPage(discoveryResponse.EndSessionEndpoint)))
http.Handle("/callback", NewCallbackHandler(keySet, oauth2Config))
err = http.ListenAndServe(":4000", http.DefaultServeMux)
if err != nil {
log.Fatal(err)
}
}
func generateKey(length int) []byte {
key := make([]byte, length)
read, err := rand.Read(key)
if err != nil {
log.Fatalf("could not generate key: %s", err)
}
if read != length {
log.Fatalf("read %d bytes, expected %d bytes", read, length)
}
return key
}
func discoverOidc(discoveryUrl *url.URL, apiClient *http.Client, o *OpenIDConfiguration) error {
var body []byte
req, err := http.NewRequest(http.MethodGet, discoveryUrl.String(), bytes.NewBuffer(body))
if err != nil {
return err
}
req.Header = map[string][]string{
"Accept": {"application/json"},
}
resp, err := apiClient.Do(req)
if err != nil {
return err
}
dec := json.NewDecoder(resp.Body)
err = dec.Decode(o)
if err != nil {
return err
}
return nil
}
type callbackHandler struct {
keySet *jwk.Set
oauth2Config *oauth2.Config
}
func (c *callbackHandler) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
if request.Method != http.MethodGet {
http.Error(writer, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
return
}
if request.URL.Path != "/callback" {
http.NotFound(writer, request)
return
}
code := request.URL.Query().Get("code")
ctx := context.Background()
httpClient, err := client.TLSClient(client.TLSClientOptions{InsecureSkipVerify: true})
ctx = context.WithValue(ctx, oauth2.HTTPClient, httpClient)
tok, err := c.oauth2Config.Exchange(ctx, code)
if err != nil {
log.Error(err)
http.Error(writer, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
return
}
session, err := sessionStore.Get(request, "resource_session")
if err != nil {
http.Error(writer, err.Error(), http.StatusInternalServerError)
return
}
session.Values[sessionKeyAccessToken] = tok.AccessToken
session.Values[sessionKeyRefreshToken] = tok.RefreshToken
session.Values[sessionKeyIdToken] = tok.Extra("id_token").(string)
idToken := tok.Extra("id_token")
if parsedIdToken, err := jwt.ParseString(idToken.(string), jwt.WithKeySet(c.keySet), jwt.WithOpenIDClaims()); err != nil {
log.Error(err)
http.Error(writer, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
return
} else {
log.Infof(`
ID Token
========
Subject: %s
Audience: %s
Issued at: %s
Issued by: %s
Not valid before: %s
Not valid after: %s
`,
parsedIdToken.Subject(),
parsedIdToken.Audience(),
parsedIdToken.IssuedAt(),
parsedIdToken.Issuer(),
parsedIdToken.NotBefore(),
parsedIdToken.Expiration(),
)
session.Values[sessionKeyUserId] = parsedIdToken.Subject()
if roles, ok := parsedIdToken.Get("Groups"); ok {
session.Values[sessionKeyRoles] = roles
}
if username, ok := parsedIdToken.Get("Username"); ok {
session.Values[sessionKeyUsername] = username
}
if email, ok := parsedIdToken.Get("Email"); ok {
session.Values[sessionKeyEmail] = email
}
}
if err = session.Save(request, writer); err != nil {
http.Error(writer, err.Error(), http.StatusInternalServerError)
}
if redirectTarget, ok := session.Values[sessionRedirectTarget]; ok {
writer.Header().Set("Location", redirectTarget.(string))
} else {
writer.Header().Set("Location", "/")
}
writer.WriteHeader(http.StatusFound)
}
func NewCallbackHandler(keySet *jwk.Set, oauth2Config *oauth2.Config) *callbackHandler {
return &callbackHandler{keySet: keySet, oauth2Config: oauth2Config}
}
func authenticate(oauth2Config *oauth2.Config) func(http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
session, err := sessionStore.Get(r, "resource_session")
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if _, ok := session.Values[sessionKeyUserId]; ok {
next.ServeHTTP(w, r)
return
}
session.Values[sessionRedirectTarget] = r.URL.String()
if err = session.Save(r, w); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
var authUrl *url.URL
if authUrl, err = url.Parse(oauth2Config.Endpoint.AuthURL); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
queryValues := authUrl.Query()
queryValues.Set("client_id", k.String("oidc.client-id"))
queryValues.Set("response_type", "code")
queryValues.Set("scope", "openid offline")
queryValues.Set("state", base64.URLEncoding.EncodeToString(generateKey(8)))
authUrl.RawQuery = queryValues.Encode()
w.Header().Set("Location", authUrl.String())
w.WriteHeader(http.StatusFound)
})
}
}
type indexHandler struct {
logoutUrl string
}
func (i indexHandler) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
if request.Method != http.MethodGet {
http.Error(writer, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
return
}
if request.URL.Path != "/" {
http.NotFound(writer, request)
return
}
writer.WriteHeader(http.StatusOK)
page, err := template.New("").Parse(`
<!DOCTYPE html>
<html lang="en">
<head><title>Auth test</title></head>
<body>
<h1>Hello {{ .User }}</h1>
<p>This is an authorization protected resource</p>
<a href="{{ .LogoutURL }}">Logout</a>
</body>
</html>
`)
if err != nil {
http.Error(writer, err.Error(), http.StatusInternalServerError)
return
}
session, err := sessionStore.Get(request, "resource_session")
if err != nil {
http.Error(writer, err.Error(), http.StatusInternalServerError)
return
}
logoutUrl, err := url.Parse(i.logoutUrl)
if err != nil {
http.Error(writer, err.Error(), http.StatusInternalServerError)
return
}
var user string
var ok bool
if user, ok = session.Values[sessionKeyUsername].(string); ok {
}
if idToken, ok := session.Values[sessionKeyIdToken].(string); ok {
logoutUrl.RawQuery = url.Values{
"id_token_hint": []string{idToken},
"post_logout_redirect_uri": []string{"/logged_out"},
}.Encode()
}
writer.Header().Add("Content-Type", "text/html")
err = page.Execute(writer, map[string]interface{}{
"User": user,
"LogoutURL": logoutUrl.String(),
})
if err != nil {
http.Error(writer, err.Error(), http.StatusInternalServerError)
return
}
}
func NewIndexPage(logoutUrl string) *indexHandler {
return &indexHandler{logoutUrl: logoutUrl}
}