oauth2_proxy/oauthproxy.go

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package main
import (
"crypto/aes"
"crypto/cipher"
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"encoding/base64"
"errors"
"fmt"
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"html/template"
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"log"
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"net"
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"net/http"
"net/http/httputil"
"net/url"
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"regexp"
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"strings"
"time"
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"github.com/bitly/oauth2_proxy/providers"
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)
type OauthProxy struct {
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CookieSeed string
CookieName string
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CookieDomain string
CookieSecure bool
CookieHttpOnly bool
CookieExpire time.Duration
CookieRefresh time.Duration
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Validator func(string) bool
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RobotsPath string
PingPath string
SignInPath string
OauthStartPath string
OauthCallbackPath string
redirectUrl *url.URL // the url to receive requests at
provider providers.Provider
ProxyPrefix string
SignInMessage string
HtpasswdFile *HtpasswdFile
DisplayHtpasswdForm bool
serveMux http.Handler
PassBasicAuth bool
PassAccessToken bool
AesCipher cipher.Block
skipAuthRegex []string
compiledRegex []*regexp.Regexp
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templates *template.Template
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}
type UpstreamProxy struct {
upstream string
handler http.Handler
}
func (u *UpstreamProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
w.Header().Set("GAP-Upstream-Address", u.upstream)
u.handler.ServeHTTP(w, r)
}
func NewReverseProxy(target *url.URL) (proxy *httputil.ReverseProxy) {
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return httputil.NewSingleHostReverseProxy(target)
}
func setProxyUpstreamHostHeader(proxy *httputil.ReverseProxy, target *url.URL) {
director := proxy.Director
proxy.Director = func(req *http.Request) {
director(req)
// use RequestURI so that we aren't unescaping encoded slashes in the request path
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req.Host = target.Host
req.URL.Opaque = req.RequestURI
req.URL.RawQuery = ""
}
}
func setProxyDirector(proxy *httputil.ReverseProxy) {
director := proxy.Director
proxy.Director = func(req *http.Request) {
director(req)
// use RequestURI so that we aren't unescaping encoded slashes in the request path
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req.URL.Opaque = req.RequestURI
req.URL.RawQuery = ""
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}
}
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func NewOauthProxy(opts *Options, validator func(string) bool) *OauthProxy {
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serveMux := http.NewServeMux()
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for _, u := range opts.proxyUrls {
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path := u.Path
u.Path = ""
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log.Printf("mapping path %q => upstream %q", path, u)
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proxy := NewReverseProxy(u)
if !opts.PassHostHeader {
setProxyUpstreamHostHeader(proxy, u)
} else {
setProxyDirector(proxy)
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}
serveMux.Handle(path, &UpstreamProxy{u.Host, proxy})
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}
for _, u := range opts.CompiledRegex {
log.Printf("compiled skip-auth-regex => %q", u)
}
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redirectUrl := opts.redirectUrl
redirectUrl.Path = fmt.Sprintf("%s/callback", opts.ProxyPrefix)
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log.Printf("OauthProxy configured for %s Client ID: %s", opts.provider.Data().ProviderName, opts.ClientID)
domain := opts.CookieDomain
if domain == "" {
domain = "<default>"
}
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log.Printf("Cookie settings: name:%s secure(https):%v httponly:%v expiry:%s domain:%s", opts.CookieName, opts.CookieSecure, opts.CookieHttpOnly, opts.CookieExpire, domain)
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var aes_cipher cipher.Block
if opts.PassAccessToken || (opts.CookieRefresh != time.Duration(0)) {
var err error
aes_cipher, err = aes.NewCipher([]byte(opts.CookieSecret))
if err != nil {
log.Fatal("error creating AES cipher with "+
"cookie-secret ", opts.CookieSecret, ": ", err)
}
}
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return &OauthProxy{
CookieName: opts.CookieName,
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CookieSeed: opts.CookieSecret,
CookieDomain: opts.CookieDomain,
CookieSecure: opts.CookieSecure,
CookieHttpOnly: opts.CookieHttpOnly,
CookieExpire: opts.CookieExpire,
CookieRefresh: opts.CookieRefresh,
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Validator: validator,
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RobotsPath: "/robots.txt",
PingPath: "/ping",
SignInPath: fmt.Sprintf("%s/sign_in", opts.ProxyPrefix),
OauthStartPath: fmt.Sprintf("%s/start", opts.ProxyPrefix),
OauthCallbackPath: fmt.Sprintf("%s/callback", opts.ProxyPrefix),
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ProxyPrefix: opts.ProxyPrefix,
provider: opts.provider,
serveMux: serveMux,
redirectUrl: redirectUrl,
skipAuthRegex: opts.SkipAuthRegex,
compiledRegex: opts.CompiledRegex,
PassBasicAuth: opts.PassBasicAuth,
PassAccessToken: opts.PassAccessToken,
AesCipher: aes_cipher,
templates: loadTemplates(opts.CustomTemplatesDir),
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}
}
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func (p *OauthProxy) GetRedirectURI(host string) string {
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// default to the request Host if not set
if p.redirectUrl.Host != "" {
return p.redirectUrl.String()
}
var u url.URL
u = *p.redirectUrl
if u.Scheme == "" {
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if p.CookieSecure {
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u.Scheme = "https"
} else {
u.Scheme = "http"
}
}
u.Host = host
return u.String()
}
func (p *OauthProxy) displayCustomLoginForm() bool {
return p.HtpasswdFile != nil && p.DisplayHtpasswdForm
}
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func (p *OauthProxy) redeemCode(host, code string) (string, string, error) {
if code == "" {
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return "", "", errors.New("missing code")
}
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redirectUri := p.GetRedirectURI(host)
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body, access_token, err := p.provider.Redeem(redirectUri, code)
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if err != nil {
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return "", "", err
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}
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email, err := p.provider.GetEmailAddress(body, access_token)
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if err != nil {
return "", "", err
}
return access_token, email, nil
}
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func (p *OauthProxy) MakeCookie(req *http.Request, value string, expiration time.Duration) *http.Cookie {
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domain := req.Host
if h, _, err := net.SplitHostPort(domain); err == nil {
domain = h
}
if p.CookieDomain != "" {
if !strings.HasSuffix(domain, p.CookieDomain) {
log.Printf("Warning: request host is %q but using configured cookie domain of %q", domain, p.CookieDomain)
}
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domain = p.CookieDomain
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}
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if value != "" {
value = signedCookieValue(p.CookieSeed, p.CookieName, value)
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}
return &http.Cookie{
Name: p.CookieName,
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Value: value,
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Path: "/",
Domain: domain,
HttpOnly: p.CookieHttpOnly,
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Secure: p.CookieSecure,
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Expires: time.Now().Add(expiration),
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}
}
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func (p *OauthProxy) ClearCookie(rw http.ResponseWriter, req *http.Request) {
http.SetCookie(rw, p.MakeCookie(req, "", time.Duration(1)*time.Hour*-1))
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}
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func (p *OauthProxy) SetCookie(rw http.ResponseWriter, req *http.Request, val string) {
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http.SetCookie(rw, p.MakeCookie(req, val, p.CookieExpire))
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}
func (p *OauthProxy) ProcessCookie(rw http.ResponseWriter, req *http.Request) (email, user, access_token string, ok bool) {
var value string
var timestamp time.Time
cookie, err := req.Cookie(p.CookieName)
if err == nil {
value, timestamp, ok = validateCookie(cookie, p.CookieSeed)
if ok {
email, user, access_token, err = parseCookieValue(
value, p.AesCipher)
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}
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}
if err != nil {
log.Printf(err.Error())
ok = false
} else if p.CookieRefresh != time.Duration(0) {
expires := timestamp.Add(p.CookieExpire)
refresh_threshold := time.Now().Add(p.CookieRefresh)
if refresh_threshold.Unix() > expires.Unix() {
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ok = p.Validator(email) && p.provider.ValidateToken(access_token)
if ok {
p.SetCookie(rw, req, value)
}
}
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}
return
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}
func (p *OauthProxy) RobotsTxt(rw http.ResponseWriter) {
rw.WriteHeader(http.StatusOK)
fmt.Fprintf(rw, "User-agent: *\nDisallow: /")
}
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func (p *OauthProxy) PingPage(rw http.ResponseWriter) {
rw.WriteHeader(http.StatusOK)
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fmt.Fprintf(rw, "OK")
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}
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func (p *OauthProxy) ErrorPage(rw http.ResponseWriter, code int, title string, message string) {
log.Printf("ErrorPage %d %s %s", code, title, message)
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rw.WriteHeader(code)
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t := struct {
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Title string
Message string
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}{
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Title: fmt.Sprintf("%d %s", code, title),
Message: message,
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}
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p.templates.ExecuteTemplate(rw, "error.html", t)
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}
func (p *OauthProxy) SignInPage(rw http.ResponseWriter, req *http.Request, code int) {
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p.ClearCookie(rw, req)
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rw.WriteHeader(code)
redirect_url := req.URL.RequestURI()
if redirect_url == p.SignInPath {
redirect_url = "/"
}
t := struct {
ProviderName string
SignInMessage string
CustomLogin bool
Redirect string
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Version string
ProxyPrefix string
}{
ProviderName: p.provider.Data().ProviderName,
SignInMessage: p.SignInMessage,
CustomLogin: p.displayCustomLoginForm(),
Redirect: redirect_url,
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Version: VERSION,
ProxyPrefix: p.ProxyPrefix,
}
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p.templates.ExecuteTemplate(rw, "sign_in.html", t)
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}
func (p *OauthProxy) ManualSignIn(rw http.ResponseWriter, req *http.Request) (string, bool) {
if req.Method != "POST" || p.HtpasswdFile == nil {
return "", false
}
user := req.FormValue("username")
passwd := req.FormValue("password")
if user == "" {
return "", false
}
// check auth
if p.HtpasswdFile.Validate(user, passwd) {
log.Printf("authenticated %q via HtpasswdFile", user)
return user, true
}
return "", false
}
func (p *OauthProxy) GetRedirect(req *http.Request) (string, error) {
err := req.ParseForm()
if err != nil {
return "", err
}
redirect := req.FormValue("rd")
if redirect == "" {
redirect = "/"
}
return redirect, err
}
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func (p *OauthProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
// check if this is a redirect back at the end of oauth
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remoteAddr := req.RemoteAddr
if req.Header.Get("X-Real-IP") != "" {
remoteAddr += fmt.Sprintf(" (%q)", req.Header.Get("X-Real-IP"))
}
var ok bool
var user string
var email string
var access_token string
if req.URL.Path == p.RobotsPath {
p.RobotsTxt(rw)
return
}
if req.URL.Path == p.PingPath {
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p.PingPage(rw)
return
}
for _, u := range p.compiledRegex {
match := u.MatchString(req.URL.Path)
if match {
p.serveMux.ServeHTTP(rw, req)
return
}
}
if req.URL.Path == p.SignInPath {
redirect, err := p.GetRedirect(req)
if err != nil {
p.ErrorPage(rw, 500, "Internal Error", err.Error())
return
}
user, ok = p.ManualSignIn(rw, req)
if ok {
p.SetCookie(rw, req, user)
http.Redirect(rw, req, redirect, 302)
} else {
p.SignInPage(rw, req, 200)
}
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return
}
if req.URL.Path == p.OauthStartPath {
redirect, err := p.GetRedirect(req)
if err != nil {
p.ErrorPage(rw, 500, "Internal Error", err.Error())
return
}
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redirectURI := p.GetRedirectURI(req.Host)
http.Redirect(rw, req, p.provider.GetLoginURL(redirectURI, redirect), 302)
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return
}
if req.URL.Path == p.OauthCallbackPath {
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// finish the oauth cycle
err := req.ParseForm()
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if err != nil {
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p.ErrorPage(rw, 500, "Internal Error", err.Error())
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return
}
errorString := req.Form.Get("error")
if errorString != "" {
p.ErrorPage(rw, 403, "Permission Denied", errorString)
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return
}
access_token, email, err = p.redeemCode(req.Host, req.Form.Get("code"))
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if err != nil {
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log.Printf("%s error redeeming code %s", remoteAddr, err)
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p.ErrorPage(rw, 500, "Internal Error", err.Error())
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return
}
redirect := req.Form.Get("state")
if redirect == "" {
redirect = "/"
}
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// set cookie, or deny
if p.Validator(email) {
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log.Printf("%s authenticating %s completed", remoteAddr, email)
value, err := buildCookieValue(
email, p.AesCipher, access_token)
if err != nil {
log.Printf("%s", err)
}
p.SetCookie(rw, req, value)
http.Redirect(rw, req, redirect, 302)
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return
} else {
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p.ErrorPage(rw, 403, "Permission Denied", "Invalid Account")
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return
}
}
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if !ok {
email, user, access_token, ok = p.ProcessCookie(rw, req)
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}
if !ok {
user, ok = p.CheckBasicAuth(req)
}
if !ok {
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p.SignInPage(rw, req, 403)
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return
}
// At this point, the user is authenticated. proxy normally
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if p.PassBasicAuth {
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req.SetBasicAuth(user, "")
req.Header["X-Forwarded-User"] = []string{user}
req.Header["X-Forwarded-Email"] = []string{email}
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}
if p.PassAccessToken {
req.Header["X-Forwarded-Access-Token"] = []string{access_token}
}
if email == "" {
rw.Header().Set("GAP-Auth", user)
} else {
rw.Header().Set("GAP-Auth", email)
}
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p.serveMux.ServeHTTP(rw, req)
}
func (p *OauthProxy) CheckBasicAuth(req *http.Request) (string, bool) {
if p.HtpasswdFile == nil {
return "", false
}
s := strings.SplitN(req.Header.Get("Authorization"), " ", 2)
if len(s) != 2 || s[0] != "Basic" {
return "", false
}
b, err := base64.StdEncoding.DecodeString(s[1])
if err != nil {
return "", false
}
pair := strings.SplitN(string(b), ":", 2)
if len(pair) != 2 {
return "", false
}
if p.HtpasswdFile.Validate(pair[0], pair[1]) {
log.Printf("authenticated %q via basic auth", pair[0])
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return pair[0], true
}
return "", false
}