/
auth_handler.go
440 lines (393 loc) · 15.9 KB
/
auth_handler.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
// Package auth provides a handler for the OIDC authorization endpoint.
package auth
import (
"fmt"
"net/http"
"time"
coreosoidc "github.com/coreos/go-oidc/v3/oidc"
"github.com/ory/fosite"
"github.com/ory/fosite/handler/openid"
"github.com/ory/fosite/token/jwt"
"github.com/pkg/errors"
"golang.org/x/oauth2"
"k8s.io/apiserver/pkg/authentication/authenticator"
supervisoroidc "go.pinniped.dev/generated/latest/apis/supervisor/oidc"
"go.pinniped.dev/internal/httputil/httperr"
"go.pinniped.dev/internal/httputil/securityheader"
"go.pinniped.dev/internal/oidc"
"go.pinniped.dev/internal/oidc/csrftoken"
"go.pinniped.dev/internal/oidc/downstreamsession"
"go.pinniped.dev/internal/oidc/provider"
"go.pinniped.dev/internal/plog"
"go.pinniped.dev/pkg/oidcclient/nonce"
"go.pinniped.dev/pkg/oidcclient/pkce"
)
func NewHandler(
downstreamIssuer string,
idpLister oidc.UpstreamIdentityProvidersLister,
oauthHelperWithoutStorage fosite.OAuth2Provider,
oauthHelperWithStorage fosite.OAuth2Provider,
generateCSRF func() (csrftoken.CSRFToken, error),
generatePKCE func() (pkce.Code, error),
generateNonce func() (nonce.Nonce, error),
upstreamStateEncoder oidc.Encoder,
cookieCodec oidc.Codec,
) http.Handler {
return securityheader.Wrap(httperr.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
if r.Method != http.MethodPost && r.Method != http.MethodGet {
// https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest
// Authorization Servers MUST support the use of the HTTP GET and POST methods defined in
// RFC 2616 [RFC2616] at the Authorization Endpoint.
return httperr.Newf(http.StatusMethodNotAllowed, "%s (try GET or POST)", r.Method)
}
oidcUpstream, ldapUpstream, err := chooseUpstreamIDP(idpLister)
if err != nil {
plog.WarningErr("authorize upstream config", err)
return err
}
if oidcUpstream != nil {
if len(r.Header.Values(supervisoroidc.AuthorizeUsernameHeaderName)) > 0 {
// The client set a username header, so they are trying to log in with a username/password.
return handleAuthRequestForOIDCUpstreamPasswordGrant(r, w, oauthHelperWithStorage, oidcUpstream)
}
return handleAuthRequestForOIDCUpstreamAuthcodeGrant(r, w,
oauthHelperWithoutStorage,
generateCSRF, generateNonce, generatePKCE,
oidcUpstream,
downstreamIssuer,
upstreamStateEncoder,
cookieCodec,
)
}
return handleAuthRequestForLDAPUpstream(r, w,
oauthHelperWithStorage,
ldapUpstream,
)
}))
}
func handleAuthRequestForLDAPUpstream(
r *http.Request,
w http.ResponseWriter,
oauthHelper fosite.OAuth2Provider,
ldapUpstream provider.UpstreamLDAPIdentityProviderI,
) error {
authorizeRequester, created := newAuthorizeRequest(r, w, oauthHelper)
if !created {
return nil
}
username, password, hadUsernamePasswordValues := requireNonEmptyUsernameAndPasswordHeaders(r, w, oauthHelper, authorizeRequester)
if !hadUsernamePasswordValues {
return nil
}
authenticateResponse, authenticated, err := ldapUpstream.AuthenticateUser(r.Context(), username, password)
if err != nil {
plog.WarningErr("unexpected error during upstream LDAP authentication", err, "upstreamName", ldapUpstream.GetName())
return httperr.New(http.StatusBadGateway, "unexpected error during upstream authentication")
}
if !authenticated {
return writeAuthorizeError(w, oauthHelper, authorizeRequester,
fosite.ErrAccessDenied.WithHintf("Username/password not accepted by LDAP provider."))
}
subject := downstreamSubjectFromUpstreamLDAP(ldapUpstream, authenticateResponse)
username = authenticateResponse.User.GetName()
groups := authenticateResponse.User.GetGroups()
return makeDownstreamSessionAndReturnAuthcodeRedirect(r, w, oauthHelper, authorizeRequester, subject, username, groups)
}
func handleAuthRequestForOIDCUpstreamPasswordGrant(
r *http.Request,
w http.ResponseWriter,
oauthHelper fosite.OAuth2Provider,
oidcUpstream provider.UpstreamOIDCIdentityProviderI,
) error {
authorizeRequester, created := newAuthorizeRequest(r, w, oauthHelper)
if !created {
return nil
}
username, password, hadUsernamePasswordValues := requireNonEmptyUsernameAndPasswordHeaders(r, w, oauthHelper, authorizeRequester)
if !hadUsernamePasswordValues {
return nil
}
if !oidcUpstream.AllowsPasswordGrant() {
// Return a user-friendly error for this case which is entirely within our control.
return writeAuthorizeError(w, oauthHelper, authorizeRequester,
fosite.ErrAccessDenied.WithHint(
"Resource owner password credentials grant is not allowed for this upstream provider according to its configuration."))
}
token, err := oidcUpstream.PasswordCredentialsGrantAndValidateTokens(r.Context(), username, password)
if err != nil {
// Upstream password grant errors can be generic errors (e.g. a network failure) or can be oauth2.RetrieveError errors
// which represent the http response from the upstream server. These could be a 5XX or some other unexpected error,
// or could be a 400 with a JSON body as described by https://datatracker.ietf.org/doc/html/rfc6749#section-5.2
// which notes that wrong resource owner credentials should result in an "invalid_grant" error.
// However, the exact response is undefined in the sense that there is no such thing as a password grant in
// the OIDC spec, so we don't try too hard to read the upstream errors in this case. (E.g. Dex departs from the
// spec and returns something other than an "invalid_grant" error for bad resource owner credentials.)
return writeAuthorizeError(w, oauthHelper, authorizeRequester,
fosite.ErrAccessDenied.WithDebug(err.Error())) // WithDebug hides the error from the client
}
subject, username, groups, err := downstreamsession.GetDownstreamIdentityFromUpstreamIDToken(oidcUpstream, token.IDToken.Claims)
if err != nil {
// Return a user-friendly error for this case which is entirely within our control.
return writeAuthorizeError(w, oauthHelper, authorizeRequester,
fosite.ErrAccessDenied.WithHintf("Reason: %s.", err.Error()),
)
}
return makeDownstreamSessionAndReturnAuthcodeRedirect(r, w, oauthHelper, authorizeRequester, subject, username, groups)
}
func handleAuthRequestForOIDCUpstreamAuthcodeGrant(
r *http.Request,
w http.ResponseWriter,
oauthHelper fosite.OAuth2Provider,
generateCSRF func() (csrftoken.CSRFToken, error),
generateNonce func() (nonce.Nonce, error),
generatePKCE func() (pkce.Code, error),
oidcUpstream provider.UpstreamOIDCIdentityProviderI,
downstreamIssuer string,
upstreamStateEncoder oidc.Encoder,
cookieCodec oidc.Codec,
) error {
authorizeRequester, created := newAuthorizeRequest(r, w, oauthHelper)
if !created {
return nil
}
now := time.Now()
_, err := oauthHelper.NewAuthorizeResponse(r.Context(), authorizeRequester, &openid.DefaultSession{
Claims: &jwt.IDTokenClaims{
// Temporary claim values to allow `NewAuthorizeResponse` to perform other OIDC validations.
Subject: "none",
AuthTime: now,
RequestedAt: now,
},
})
if err != nil {
return writeAuthorizeError(w, oauthHelper, authorizeRequester, err)
}
csrfValue, nonceValue, pkceValue, err := generateValues(generateCSRF, generateNonce, generatePKCE)
if err != nil {
plog.Error("authorize generate error", err)
return err
}
csrfFromCookie := readCSRFCookie(r, cookieCodec)
if csrfFromCookie != "" {
csrfValue = csrfFromCookie
}
upstreamOAuthConfig := oauth2.Config{
ClientID: oidcUpstream.GetClientID(),
Endpoint: oauth2.Endpoint{
AuthURL: oidcUpstream.GetAuthorizationURL().String(),
},
RedirectURL: fmt.Sprintf("%s/callback", downstreamIssuer),
Scopes: oidcUpstream.GetScopes(),
}
encodedStateParamValue, err := upstreamStateParam(
authorizeRequester,
oidcUpstream.GetName(),
nonceValue,
csrfValue,
pkceValue,
upstreamStateEncoder,
)
if err != nil {
plog.Error("authorize upstream state param error", err)
return err
}
if csrfFromCookie == "" {
// We did not receive an incoming CSRF cookie, so write a new one.
err := addCSRFSetCookieHeader(w, csrfValue, cookieCodec)
if err != nil {
plog.Error("error setting CSRF cookie", err)
return err
}
}
authCodeOptions := []oauth2.AuthCodeOption{
oauth2.AccessTypeOffline,
nonceValue.Param(),
pkceValue.Challenge(),
pkceValue.Method(),
}
promptParam := r.Form.Get("prompt")
if promptParam != "" && oidc.ScopeWasRequested(authorizeRequester, coreosoidc.ScopeOpenID) {
authCodeOptions = append(authCodeOptions, oauth2.SetAuthURLParam("prompt", promptParam))
}
http.Redirect(w, r,
upstreamOAuthConfig.AuthCodeURL(
encodedStateParamValue,
authCodeOptions...,
),
302,
)
return nil
}
func writeAuthorizeError(w http.ResponseWriter, oauthHelper fosite.OAuth2Provider, authorizeRequester fosite.AuthorizeRequester, err error) error {
if plog.Enabled(plog.LevelTrace) {
// When trace level logging is enabled, include the stack trace in the log message.
keysAndValues := oidc.FositeErrorForLog(err)
errWithStack := errors.WithStack(err)
keysAndValues = append(keysAndValues, "errWithStack")
// klog always prints error values using %s, which does not include stack traces,
// so convert the error to a string which includes the stack trace here.
keysAndValues = append(keysAndValues, fmt.Sprintf("%+v", errWithStack))
plog.Trace("authorize response error", keysAndValues...)
} else {
plog.Info("authorize response error", oidc.FositeErrorForLog(err)...)
}
// Return an error according to OIDC spec 3.1.2.6 (second paragraph).
oauthHelper.WriteAuthorizeError(w, authorizeRequester, err)
return nil
}
func makeDownstreamSessionAndReturnAuthcodeRedirect(
r *http.Request,
w http.ResponseWriter,
oauthHelper fosite.OAuth2Provider,
authorizeRequester fosite.AuthorizeRequester,
subject string,
username string,
groups []string,
) error {
openIDSession := downstreamsession.MakeDownstreamSession(subject, username, groups)
authorizeResponder, err := oauthHelper.NewAuthorizeResponse(r.Context(), authorizeRequester, openIDSession)
if err != nil {
return writeAuthorizeError(w, oauthHelper, authorizeRequester, err)
}
oauthHelper.WriteAuthorizeResponse(w, authorizeRequester, authorizeResponder)
return nil
}
func requireNonEmptyUsernameAndPasswordHeaders(r *http.Request, w http.ResponseWriter, oauthHelper fosite.OAuth2Provider, authorizeRequester fosite.AuthorizeRequester) (string, string, bool) {
username := r.Header.Get(supervisoroidc.AuthorizeUsernameHeaderName)
password := r.Header.Get(supervisoroidc.AuthorizePasswordHeaderName)
if username == "" || password == "" {
_ = writeAuthorizeError(w, oauthHelper, authorizeRequester,
fosite.ErrAccessDenied.WithHintf("Missing or blank username or password."))
return "", "", false
}
return username, password, true
}
func newAuthorizeRequest(r *http.Request, w http.ResponseWriter, oauthHelper fosite.OAuth2Provider) (fosite.AuthorizeRequester, bool) {
authorizeRequester, err := oauthHelper.NewAuthorizeRequest(r.Context(), r)
if err != nil {
_ = writeAuthorizeError(w, oauthHelper, authorizeRequester, err)
return nil, false
}
// Automatically grant the openid, offline_access, and pinniped:request-audience scopes, but only if they were requested.
// Grant the openid scope (for now) if they asked for it so that `NewAuthorizeResponse` will perform its OIDC validations.
// There don't seem to be any validations inside `NewAuthorizeResponse` related to the offline_access scope
// at this time, however we will temporarily grant the scope just in case that changes in a future release of fosite.
downstreamsession.GrantScopesIfRequested(authorizeRequester)
return authorizeRequester, true
}
func readCSRFCookie(r *http.Request, codec oidc.Decoder) csrftoken.CSRFToken {
receivedCSRFCookie, err := r.Cookie(oidc.CSRFCookieName)
if err != nil {
// Error means that the cookie was not found
return ""
}
var csrfFromCookie csrftoken.CSRFToken
err = codec.Decode(oidc.CSRFCookieEncodingName, receivedCSRFCookie.Value, &csrfFromCookie)
if err != nil {
// We can ignore any errors and just make a new cookie. Hopefully this will
// make the user experience better if, for example, the server rotated
// cookie signing keys and then a user submitted a very old cookie.
return ""
}
return csrfFromCookie
}
// Select either an OIDC, an LDAP or an AD IDP, or return an error.
func chooseUpstreamIDP(idpLister oidc.UpstreamIdentityProvidersLister) (provider.UpstreamOIDCIdentityProviderI, provider.UpstreamLDAPIdentityProviderI, error) {
oidcUpstreams := idpLister.GetOIDCIdentityProviders()
ldapUpstreams := idpLister.GetLDAPIdentityProviders()
adUpstreams := idpLister.GetActiveDirectoryIdentityProviders()
switch {
case len(oidcUpstreams)+len(ldapUpstreams)+len(adUpstreams) == 0:
return nil, nil, httperr.New(
http.StatusUnprocessableEntity,
"No upstream providers are configured",
)
case len(oidcUpstreams)+len(ldapUpstreams)+len(adUpstreams) > 1:
var upstreamIDPNames []string
for _, idp := range oidcUpstreams {
upstreamIDPNames = append(upstreamIDPNames, idp.GetName())
}
for _, idp := range ldapUpstreams {
upstreamIDPNames = append(upstreamIDPNames, idp.GetName())
}
for _, idp := range adUpstreams {
upstreamIDPNames = append(upstreamIDPNames, idp.GetName())
}
plog.Warning("Too many upstream providers are configured (found: %s)", upstreamIDPNames)
return nil, nil, httperr.New(
http.StatusUnprocessableEntity,
"Too many upstream providers are configured (support for multiple upstreams is not yet implemented)",
)
case len(oidcUpstreams) == 1:
return oidcUpstreams[0], nil, nil
case len(adUpstreams) == 1:
return nil, adUpstreams[0], nil
default:
return nil, ldapUpstreams[0], nil
}
}
func generateValues(
generateCSRF func() (csrftoken.CSRFToken, error),
generateNonce func() (nonce.Nonce, error),
generatePKCE func() (pkce.Code, error),
) (csrftoken.CSRFToken, nonce.Nonce, pkce.Code, error) {
csrfValue, err := generateCSRF()
if err != nil {
return "", "", "", httperr.Wrap(http.StatusInternalServerError, "error generating CSRF token", err)
}
nonceValue, err := generateNonce()
if err != nil {
return "", "", "", httperr.Wrap(http.StatusInternalServerError, "error generating nonce param", err)
}
pkceValue, err := generatePKCE()
if err != nil {
return "", "", "", httperr.Wrap(http.StatusInternalServerError, "error generating PKCE param", err)
}
return csrfValue, nonceValue, pkceValue, nil
}
func upstreamStateParam(
authorizeRequester fosite.AuthorizeRequester,
upstreamName string,
nonceValue nonce.Nonce,
csrfValue csrftoken.CSRFToken,
pkceValue pkce.Code,
encoder oidc.Encoder,
) (string, error) {
stateParamData := oidc.UpstreamStateParamData{
AuthParams: authorizeRequester.GetRequestForm().Encode(),
UpstreamName: upstreamName,
Nonce: nonceValue,
CSRFToken: csrfValue,
PKCECode: pkceValue,
FormatVersion: oidc.UpstreamStateParamFormatVersion,
}
encodedStateParamValue, err := encoder.Encode(oidc.UpstreamStateParamEncodingName, stateParamData)
if err != nil {
return "", httperr.Wrap(http.StatusInternalServerError, "error encoding upstream state param", err)
}
return encodedStateParamValue, nil
}
func addCSRFSetCookieHeader(w http.ResponseWriter, csrfValue csrftoken.CSRFToken, codec oidc.Encoder) error {
encodedCSRFValue, err := codec.Encode(oidc.CSRFCookieEncodingName, csrfValue)
if err != nil {
return httperr.Wrap(http.StatusInternalServerError, "error encoding CSRF cookie", err)
}
http.SetCookie(w, &http.Cookie{
Name: oidc.CSRFCookieName,
Value: encodedCSRFValue,
HttpOnly: true,
SameSite: http.SameSiteLaxMode,
Secure: true,
Path: "/",
})
return nil
}
func downstreamSubjectFromUpstreamLDAP(ldapUpstream provider.UpstreamLDAPIdentityProviderI, authenticateResponse *authenticator.Response) string {
ldapURL := *ldapUpstream.GetURL()
q := ldapURL.Query()
q.Set(oidc.IDTokenSubjectClaim, authenticateResponse.User.GetUID())
ldapURL.RawQuery = q.Encode()
return ldapURL.String()
}