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
|
;; webid-oidc, implementation of the Solid specification
;; Copyright (C) 2020, 2021 Vivien Kraus
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU Affero General Public License as
;; published by the Free Software Foundation, either version 3 of the
;; License, or (at your option) any later version.
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU Affero General Public License for more details.
;; You should have received a copy of the GNU Affero General Public License
;; along with this program. If not, see <https://www.gnu.org/licenses/>.
(define-module (webid-oidc dpop-proof)
#:use-module (webid-oidc jws)
#:use-module (webid-oidc errors)
#:use-module (webid-oidc jwk)
#:use-module (webid-oidc jti)
#:use-module ((webid-oidc stubs) #:prefix stubs:)
#:use-module ((webid-oidc parameters) #:prefix p:)
#:use-module (web uri)
#:use-module (ice-9 optargs)
#:use-module (srfi srfi-19))
(define-public (the-dpop-proof-header x)
(with-exception-handler
(lambda (error)
(raise-not-a-dpop-proof-header x error))
(lambda ()
(let ((x (the-jws-header x)))
(let ((alg (assq-ref x 'alg))
(typ (assq-ref x 'typ))
(jwk (assq-ref x 'jwk)))
(unless (and alg (string? alg))
(raise-unsupported-alg alg))
(case (string->symbol alg)
((RS256 RS384 RS512 ES256 ES384 ES512 PS256 PS384 PS512)
#t)
(else
(raise-unsupported-alg alg)))
(unless (equal? typ "dpop+jwt")
(raise-incorrect-typ-field typ))
(with-exception-handler
(lambda (error)
(raise-incorrect-jwk-field jwk error))
(lambda ()
(the-public-jwk jwk)))
x)))))
(define-public (dpop-proof-header? x)
(false-if-exception
(and (the-dpop-proof-header x) #t)))
(define-public (the-dpop-proof-payload x)
(with-exception-handler
(lambda (error)
(raise-not-a-dpop-proof-payload x error))
(lambda ()
(let ((x (the-jws-payload x)))
(let ((jti (assq-ref x 'jti))
(htm (assq-ref x 'htm))
(htu (assq-ref x 'htu))
(iat (assq-ref x 'iat))
(ath (assq-ref x 'ath)))
(unless (and jti (string? jti))
(raise-incorrect-jti-field jti))
(unless (and htm (string? htm))
(raise-incorrect-htm-field htm))
(unless (and htu (string? htu) (string->uri htu))
(raise-incorrect-htu-field htu))
(unless (and iat (integer? iat))
(raise-incorrect-iat-field iat))
(unless (or (not ath) (string? ath))
(raise-incorrect-ath-field ath))
x)))))
(define-public (dpop-proof-payload? x)
(false-if-exception
(and (the-dpop-proof-payload x) #t)))
(define-public (the-dpop-proof x)
(with-exception-handler
(lambda (error)
(raise-not-a-dpop-proof x error))
(lambda ()
(cons (the-dpop-proof-header (car x))
(the-dpop-proof-payload (cdr x))))))
(define-public (dpop-proof? x)
(false-if-exception
(and (the-dpop-proof x) #t)))
(define-public (make-dpop-proof header payload)
(the-dpop-proof (cons header payload)))
(define-public (make-dpop-proof-header alg jwk)
(when (symbol? alg)
(set! alg (symbol->string alg)))
(the-dpop-proof-header
`((alg . ,alg)
(typ . "dpop+jwt")
(jwk . ,(stubs:strip-key jwk)))))
(define-public (make-dpop-proof-payload jti htm htu iat ath)
(when (symbol? htm)
(set! htm (symbol->string htm)))
(when (uri? htu)
(set! htu (uri->string htu)))
(when (date? iat)
(set! iat (date->time-utc iat)))
(when (time? iat)
(set! iat (time-second iat)))
(the-dpop-proof-payload
`((jti . ,jti)
(htm . ,htm)
(htu . ,htu)
(iat . ,iat)
,@(if ath
`((ath . ,ath))
'()))))
(define-public (dpop-proof-header dpop)
(car (the-dpop-proof dpop)))
(define-public (dpop-proof-payload dpop)
(cdr (the-dpop-proof dpop)))
(define-public (dpop-proof-alg code)
(when (dpop-proof? code)
(set! code (dpop-proof-header code)))
(jws-alg (the-dpop-proof-header code)))
(define-public (dpop-proof-jwk dpop)
(when (dpop-proof? dpop)
(set! dpop (dpop-proof-header dpop)))
(assq-ref (the-dpop-proof-header dpop) 'jwk))
(define-public (dpop-proof-jti dpop)
(when (dpop-proof? dpop)
(set! dpop (dpop-proof-payload dpop)))
(assq-ref (the-dpop-proof-payload dpop) 'jti))
(define-public (dpop-proof-htm dpop)
(when (dpop-proof? dpop)
(set! dpop (dpop-proof-payload dpop)))
(string->symbol
(assq-ref (the-dpop-proof-payload dpop)
'htm)))
(define-public (dpop-proof-htu dpop)
(when (dpop-proof? dpop)
(set! dpop (dpop-proof-payload dpop)))
(string->uri
(assq-ref (the-dpop-proof-payload dpop)
'htu)))
(define-public (dpop-proof-iat dpop)
(when (dpop-proof? dpop)
(set! dpop (dpop-proof-payload dpop)))
(time-utc->date
(make-time time-utc
0
(assq-ref (the-dpop-proof-payload dpop)
'iat))))
(define-public (dpop-proof-ath dpop)
(when (dpop-proof? dpop)
(set! dpop (dpop-proof-payload dpop)))
(assq-ref (the-dpop-proof-payload dpop)
'ath))
(define (uris-compatible a b)
;; a is what is signed, b is the request
(unless
(and (eq? (uri-scheme a)
(uri-scheme b))
(equal? (uri-userinfo a)
(uri-userinfo b))
(equal? (uri-port a)
(uri-port b))
(equal? (split-and-decode-uri-path
(uri-path a))
(split-and-decode-uri-path
(uri-path b))))
(raise-dpop-uri-mismatch a b)))
(define*-public (dpop-proof-decode method uri str cnf/check
#:key
(access-token #f))
(let ((current-time
(time-second (date->time-utc ((p:current-date))))))
(with-exception-handler
(lambda (error)
(raise-cannot-decode-dpop-proof str error))
(lambda ()
(let ((decoded (the-dpop-proof (jws-decode str dpop-proof-jwk))))
(unless (eq? method (dpop-proof-htm decoded))
(raise-dpop-method-mismatch (dpop-proof-htm decoded) method))
(uris-compatible (dpop-proof-htu decoded)
(if (string? uri)
(string->uri uri)
uri))
(let ((iat (time-second (date->time-utc (dpop-proof-iat decoded)))))
(unless (>= current-time (- iat 5))
(raise-dpop-signed-in-future iat current-time))
(unless (<= current-time (+ iat 120)) ;; Valid for 2 min
(raise-dpop-too-old iat current-time)))
(when access-token
(let ((h (stubs:hash 'SHA-256 access-token)))
(unless (equal? (dpop-proof-ath decoded) h)
(raise-exception
(make-dpop-invalid-access-token-hash (dpop-proof-ath decoded) access-token)))))
(if (string? cnf/check)
(unless (equal? cnf/check (stubs:jkt (dpop-proof-jwk decoded)))
(raise-dpop-unconfirmed-key (dpop-proof-jwk decoded) cnf/check #f))
(with-exception-handler
(lambda (error)
(raise-dpop-unconfirmed-key (dpop-proof-jwk decoded) #f error))
(lambda ()
(unless (cnf/check (stubs:jkt (dpop-proof-jwk decoded)))
;; deprecated; throw an error instead!
(error "the cnf/check function returned #f")))))
(parameterize ((p:current-date current-time))
;; jti-check should use the same date.
(unless (jti-check (dpop-proof-jti decoded) 120)
(with-exception-handler
(lambda (error)
(raise-jti-found (dpop-proof-jti decoded) error))
(lambda ()
(error "the jti-check function returned #f"))))
decoded))))))
(define-public (dpop-proof-encode dpop-proof key)
(with-exception-handler
(lambda (error)
(raise-cannot-encode-dpop-proof dpop-proof key error))
(lambda ()
(jws-encode dpop-proof key))))
(define*-public (issue-dpop-proof
client-key
#:key
(alg #f)
(htm #f)
(htu #f)
(access-token #f))
(dpop-proof-encode
(make-dpop-proof (make-dpop-proof-header alg client-key)
(make-dpop-proof-payload (stubs:random 12) htm htu ((p:current-date))
(and access-token
(stubs:hash 'SHA-256 access-token))))
client-key))
|
