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;; disfluid, 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 oidc-id-token)
#:use-module (webid-oidc oidc-configuration)
#:use-module (webid-oidc errors)
#:use-module (webid-oidc jws)
#:use-module (webid-oidc jwk)
#:use-module (webid-oidc jti)
#:use-module (webid-oidc web-i18n)
#:use-module ((webid-oidc stubs) #:prefix stubs:)
#:use-module ((webid-oidc parameters) #:prefix p:)
#:use-module (web uri)
#:use-module (web client)
#:use-module (ice-9 optargs)
#:use-module (ice-9 exceptions)
#:use-module (ice-9 match)
#:use-module (srfi srfi-19)
#:declarative? #t
#:export
(
&invalid-id-token
make-invalid-id-token
invalid-id-token?
the-id-token
id-token?
id-token-alg
id-token-webid
id-token-iss
id-token-sub
id-token-aud
id-token-nonce
id-token-iat
id-token-exp
id-token-decode
issue-id-token
))
(define-exception-type
&invalid-id-token
&external-error
make-invalid-id-token
invalid-id-token?)
(define (the-id-token x)
(with-exception-handler
(lambda (error)
(let ((final-message
(cond
((and (invalid-jws? error)
(exception-with-message? error))
(format #f (G_ "this is not an ID token, because it is not even a JWS: ~a")
(exception-message error)))
((invalid-jws? error)
(format #f (G_ "this is not an ID token, because it is not even a JWS")))
((exception-with-message? error)
(format #f (G_ "this is not an ID token: ~a")
(exception-message error)))
(else
(format #f (G_ "this is not an ID token"))))))
(raise-exception
(make-exception
(make-invalid-id-token)
(make-exception-with-message final-message)
error))))
(lambda ()
(match (the-jws x)
((header . payload)
(let examine-payload ((payload payload)
(webid #f)
(iss #f)
(sub #f)
(aud #f)
(nonce #f)
(iat #f)
(exp #f)
(other-fields '()))
(match payload
(()
(unless (and webid iss sub aud nonce iat exp)
(fail (format #f (G_ "the payload is missing ~s")
`(,@(if webid '() '("webid"))
,@(if iss '() '("iss"))
,@(if sub '() '("sub"))
,@(if aud '() '("aud"))
,@(if nonce '() '("nonce"))
,@(if iat '() '("iat"))
,@(if exp '() '("exp"))))))
`(,header
. ((webid . ,(uri->string webid))
(iss . ,(uri->string iss))
(sub . ,sub)
(aud . ,(uri->string aud))
(nonce . ,nonce)
(iat . ,(time-second (date->time-utc iat)))
(exp . ,(time-second (date->time-utc exp))))))
((('webid . (? string? (= string->uri (? uri? webid-given)))) payload ...)
(examine-payload payload
(or webid webid-given)
iss sub aud nonce iat exp other-fields))
((('webid . invalid) payload ...)
(fail (format #f (G_ "the \"webid\" field should be an URI, ~s is given")
invalid)))
((('iss . (? string? (= string->uri (? uri? iss-given)))) payload ...)
(examine-payload payload webid
(or iss iss-given)
sub aud nonce iat exp other-fields))
((('iss . invalid) payload ...)
(fail (format #f (G_ "the \"iss\" field should be an URI, ~s is given")
invalid)))
((('sub . (? string? sub-given)) payload ...)
(examine-payload payload webid iss
(or sub sub-given)
aud nonce iat exp other-fields))
((('sub . invalid) payload ...)
(fail (format #f (G_ "the \"sub\" field should be a string, ~s is given")
invalid)))
((('aud . (? string? (= string->uri (? uri? aud-given)))) payload ...)
(examine-payload payload webid iss sub
(or aud aud-given)
nonce iat exp other-fields))
((('aud . invalid) payload ...)
(fail (format #f (G_ "the \"aud\" field should be an URI, ~s is given")
invalid)))
((('nonce . (? string? nonce-given)) payload ...)
(examine-payload payload webid iss sub aud
(or nonce nonce-given)
iat exp other-fields))
((('nonce . invalid) payload ...)
(fail (format #f (G_ "the \"nonce\" field should be a string, ~s is given")
invalid)))
((('iat . (? (lambda (x) (>= x 0)) (? integer? iat-given))) payload ...)
(examine-payload payload webid iss sub aud nonce
(or iat (time-utc->date (make-time time-utc 0 iat-given)))
exp other-fields))
((('iat . invalid) payload ...)
(fail (format #f (G_ "the \"iat\" field should be a timestamp, ~s is given")
invalid)))
((('exp . (? (lambda (x) (>= x 0)) (? integer? exp-given))) payload ...)
(examine-payload payload webid iss sub aud nonce iat
(or exp (time-utc->date (make-time time-utc 0 exp-given)))
other-fields))
((('exp . invalid) payload ...)
(fail (format #f (G_ "the \"exp\" field should be a timestamp, ~s is given")
invalid)))
((field payload ...)
(examine-payload payload webid iss sub aud nonce iat exp
`(,field ,@other-fields)))
(else
(fail (format #f (G_ "the payload should be a JSON object")))))))))))
(define (id-token? x)
(false-if-exception
(the-id-token x)))
(define (id-token-alg code)
(match (the-id-token code)
((header . _)
(string->symbol (assq-ref header 'alg)))))
(define (id-token-webid code)
(match (the-id-token code)
((_ . payload)
(string->uri (assq-ref payload 'webid)))))
(define (id-token-iss code)
(match (the-id-token code)
((_ . payload)
(string->uri (assq-ref payload 'iss)))))
(define (id-token-sub code)
(match (the-id-token code)
((_ . payload)
(assq-ref payload 'sub))))
(define (id-token-aud code)
(match (the-id-token code)
((_ . payload)
(string->uri (assq-ref payload 'aud)))))
(define (id-token-nonce code)
(match (the-id-token code)
((_ . payload)
(assq-ref payload 'nonce))))
(define (id-token-iat code)
(match (the-id-token code)
((_ . payload)
(time-utc->date
(make-time time-utc 0 (assq-ref payload 'iat))))))
(define (id-token-exp code)
(match (the-id-token code)
((_ . payload)
(time-utc->date
(make-time time-utc 0 (assq-ref payload 'exp))))))
(define* (id-token-decode str #:key (http-get http-get))
(with-exception-handler
(lambda (error)
(let ((final-message
(if (exception-with-message? error)
(format #f (G_ "the ID token is invalid: ~a")
(exception-message error))
(format #f (G_ "the ID token is invalid")))))
(raise-exception
(make-exception
(make-invalid-id-token)
(make-exception-with-message final-message)
error))))
(lambda ()
(jws-decode
str
(lambda (token)
(let ((iss (id-token-iss token)))
(let* ((cfg
(with-exception-handler
(lambda (error)
(let ((final-message
(if (exception-with-message? error)
(format #f (G_ "I cannot query the identity provider configuration: ~a")
(exception-message error))
(format #f (G_ "I cannot query the identity provider configuratioon")))))
(raise-exception
(make-exception
(make-cannot-query-identity-provider iss)
(make-exception-with-message final-message)
error))))
(lambda ()
(get-oidc-configuration
(uri-host iss)
#:userinfo (uri-userinfo iss)
#:port (uri-port iss)
#:http-get http-get))))
(jwks
(with-exception-handler
(lambda (error)
(raise-exception
(make-exception
(make-cannot-query-identity-provider iss)
(make-exception-with-message
(if (exception-with-message? error)
(format #f (G_ "I cannot query the JWKS URI of the identity provider: ~a")
(exception-message error))
(format #f (G_ "I cannot query the JWKS URI of the identity provider")))))))
(lambda ()
(oidc-configuration-jwks cfg #:http-get http-get)))))
(let ((iat (id-token-iat token))
(exp (id-token-exp token))
(current-date ((p:current-date))))
(let ((iat-s (time-second (date->time-utc iat)))
(exp-s (time-second (date->time-utc exp)))
(current-s (time-second (date->time-utc current-date))))
(when (>= iat-s (+ current-s 5))
(let ((final-message
(format #f (G_ "the ID token is signed in the future, ~a, relative to current ~a")
(date->string iat)
(date->string current-date))))
(raise-exception
(make-exception
(make-signed-in-future iat current-date)
(make-exception-with-message final-message)))))
(when (>= current-s exp-s)
(let ((final-message
(format #f (G_ "the ID token expired ~a, which is in the past (from ~a)")
(date->string exp)
(date->string current-date))))
(raise-exception
(make-exception
(make-expired exp current-date)
(make-exception-with-message final-message)))))))
jwks)))))))
(define (id-token-encode id-token key)
(with-exception-handler
(lambda (error)
(let ((final-message
(if (exception-with-message? error)
(format #f (G_ "cannot encode the ID token: ~a")
(exception-message error))
(format #f (G_ "cannot encode the ID token")))))
(raise-exception
(make-exception-with-message final-message))))
(lambda ()
(jws-encode id-token key))))
(define* (issue-id-token
issuer-key
#:key
(webid #f)
(iss #f)
(sub #f)
(aud #f)
(validity 3600))
(unless sub
(set! sub (uri->string webid)))
(let* ((iat (time-second (date->time-utc ((p:current-date)))))
(exp (+ iat validity)))
(jws-encode
(the-id-token
`(((alg . ,(symbol->string (alg issuer-key))))
. ((webid . ,(uri->string webid))
(iss . ,(uri->string iss))
(sub . ,sub)
(aud . ,(uri->string aud))
(nonce . ,(stubs:random 12))
(iat . ,iat)
(exp . ,exp))))
issuer-key)))
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