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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 token-endpoint)
#:use-module (webid-oidc errors)
#:use-module (webid-oidc authorization-code)
#:use-module (webid-oidc dpop-proof)
#:use-module (webid-oidc jws)
#:use-module (webid-oidc jwk)
#:use-module (webid-oidc oidc-id-token)
#:use-module (webid-oidc access-token)
#:use-module (webid-oidc web-i18n)
#:use-module ((webid-oidc parameters) #:prefix p:)
#:use-module ((webid-oidc stubs) #:prefix stubs:)
#:use-module ((webid-oidc refresh-token) #:prefix refresh:)
#:use-module (web request)
#:use-module (web response)
#:use-module (web uri)
#:use-module (ice-9 optargs)
#:use-module (ice-9 receive)
#:use-module (ice-9 control)
#:use-module (ice-9 exceptions)
#:use-module (srfi srfi-19)
#:use-module (rnrs bytevectors)
#:use-module (sxml simple)
#:use-module (sxml match)
#:use-module (oop goops)
#:duplicates (merge-generics)
#:declarative? #t
#:export
(
&unsupported-grant-type
make-unsupported-grant-type
unsupported-grant-type?
unsupported-grant-type-grant-type
&no-authorization-code
make-no-authorization-code
no-authorization-code?
&no-refresh-token
make-no-refresh-token
no-refresh-token?
make-token-endpoint
))
(define-exception-type
&unsupported-grant-type
&external-error
make-unsupported-grant-type
unsupported-grant-type?
(grant-type unsupported-grant-type-grant-type))
(define-exception-type
&no-authorization-code
&external-error
make-no-authorization-code
no-authorization-code?)
(define-exception-type
&no-refresh-token
&external-error
make-no-refresh-token
no-refresh-token?)
(define (try-handle-web-failure thunk)
(call/ec
(lambda (return)
(with-exception-handler
(lambda (error)
(unless (or (unsupported-grant-type? error)
(no-authorization-code? error)
(no-refresh-token? error)
(refresh:invalid-refresh-token? error)
(invalid-authorization-code? error))
(let ((final-message
(if (exception-with-message? error)
(format #f (G_ "while handling web failure for the token endpoint: ~a")
(exception-message error))
(format #f (G_ "an error happened during the token endpoint failure handling")))))
(raise-exception
(make-exception
(make-exception-with-message final-message)
error))))
(cond
((refresh:invalid-refresh-token? error)
(return
(build-response
#:code 403
#:reason-phrase (G_ "reason-phrase|Forbidden")
#:headers '((content-type application/xhtml-xml)))
(call-with-output-string
(lambda (port)
(sxml->xml
`(*TOP*
(*PI* xml "version=\"1.0\" encoding=\"utf-8\"")
(html (@ (xmlns "http://www.w3.org/1999/xhtml")
(xml:lang ,(W_ "xml-lang|en")))
(body
,(sxml-match
(xml->sxml
(W_ (format #f "<h1>Invalid refresh token</h1>")))
((*TOP* ,title) title))
,(sxml-match
(xml->sxml
(W_ (format #f "<p>The refresh token you sent is invalid, or it is already bound to another key.</p>")))
((*TOP* ,p) p))
,@(if (message-for-the-user? error)
(user-message error)
'()))))
port)))))
((invalid-authorization-code? error)
(return
(build-response
#:code 400
#:reason-phrase (G_ "reason-phrase|Bad Request")
#:headers '((content-type application/xhtml-xml)))
(call-with-output-string
(lambda (port)
(sxml->xml
`(*TOP*
(*PI* xml "version=\"1.0\" encoding=\"utf-8\"")
(html (@ (xmlns "http://www.w3.org/1999/xhtml")
(xml:lang ,(W_ "xml-lang|en")))
(body
,(sxml-match
(xml->sxml
(W_ (format #f "<h1>Invalid authorization code</h1>")))
((*TOP* ,title) title))
,(sxml-match
(xml->sxml
(W_ (format #f "<p>The authorization code is forged, or expired.</p>")))
((*TOP* ,p) p))
,@(if (message-for-the-user? error)
(user-message error)
'()))))
port)))))
;; Other bad request
(else
(return
(build-response
#:code 400
#:reason-phrase (G_ "reason-phrase|Bad Request")
#:headers '((content-type application/xhtml+xml)))
(call-with-output-string
(lambda (port)
(sxml->xml
`(*TOP*
(*PI* xml "version=\"1.0\" encoding=\"utf-8\"")
(html (@ (xmlns "http://www.w3.org/1999/xhtml")
(xml:lang ,(W_ "xml-lang|en")))
(body
,(sxml-match
(xml->sxml
(W_ (format #f "<h1>Bad token request</h1>")))
((*TOP* ,title) title))
,(sxml-match
(xml->sxml
(W_ (format #f "<p>The token request failed.</p>")))
((*TOP* ,p) p))
,@(if (message-for-the-user? error)
(user-message error)
'()))))
port)))))))
thunk))))
(define (make-token-endpoint token-endpoint-uri iss issuer-key)
(lambda (request request-body)
(when (bytevector? request-body)
(set! request-body (utf8->string request-body)))
(try-handle-web-failure
(lambda ()
(parameterize ((p:current-date ((p:current-date)))
(web-locale request))
(let ((current-time ((p:current-date))) ;; thunk parameter
(form-args
(if (and (request-content-type request)
(eq? (car (request-content-type request))
'application/x-www-form-urlencoded))
(filter
(lambda (x) x)
(map (lambda (kv)
(let ((parsed
(list->vector
(map (lambda (x)
(uri-decode x #:decode-plus-to-space? #t))
(string-split kv #\=)))))
(if (eq? (vector-length parsed) 2)
`(,(vector-ref parsed 0) . ,(vector-ref parsed 1))
#f)))
(string-split request-body #\&)))
'()))
(method (request-method request))
;; Maybe we’re behind a reverse proxy, so the authority of
;; (request-uri request) is meaningless.
(uri (build-uri (uri-scheme token-endpoint-uri)
#:userinfo (uri-userinfo token-endpoint-uri)
#:host (uri-host token-endpoint-uri)
#:port (uri-port token-endpoint-uri)
#:path (uri-path (request-uri request))
#:query (uri-query (request-uri request)))))
(let ((grant-type (assoc-ref form-args "grant_type"))
(dpop (decode <dpop-proof> (assq-ref (request-headers request) 'dpop)
#:method method
#:uri uri
#:cnf/check
(lambda (jkt) #t))))
(unless (and grant-type (string? grant-type))
(let ((final-message
(format #f (G_ "missing grant type")))
(final-user-message
(sxml-match
(xml->sxml
(format #f (W_ "<p>You did not specify a grant_type for this request.</p>")))
((*TOP* ,p) p))))
(raise-exception
(make-exception
(make-unsupported-grant-type #f)
(make-exception-with-message final-message)
(make-message-for-the-user final-user-message)))))
(receive (webid client-id)
(case (string->symbol grant-type)
((authorization_code)
(let ((code
(let ((str (assoc-ref form-args "code")))
(unless str
(let ((final-message
(format #f (G_ "missing authorization code")))
(final-user-message
(sxml-match
(xml->sxml
(format #f (W_ "<p>You want to grant an authorization code, but you did not set one.</p>")))
((*TOP* ,p) p))))
(raise-exception
(make-exception
(make-no-authorization-code)
(make-exception-with-message final-message)
(make-message-for-the-user final-user-message)))))
(with-exception-handler
(lambda (error)
(raise-exception
(make-exception
(make-invalid-authorization-code)
error)))
(lambda ()
(decode <authorization-code> str
#:issuer-key issuer-key))))))
(values (webid code) (client-id code))))
((refresh_token)
(let ((refresh-token (assoc-ref form-args "refresh_token")))
(unless refresh-token
(let ((final-message
(format #f (G_ "missing refresh token")))
(final-user-message
(sxml-match
(xml->sxml
(format #f (W_ "<p>You want to grant a refresh token, but you did not set one.</p>")))
((*TOP* ,p) p))))
(raise-exception
(make-exception
(make-no-refresh-token)
(make-exception-with-message final-message)
(make-message-for-the-user final-user-message)))))
(refresh:with-refresh-token
refresh-token
(jwk dpop)
values)))
(else
(let ((final-message
(format #f (G_ "unsupported grant type: ~s")
grant-type))
(final-user-message
(sxml-match
(xml->sxml
(format #f (W_ "<p>You want to use <pre>~s</pre> as a grant type, but this is not supported.</p>")
grant-type))
((*TOP* ,p) p))))
(raise-exception
(make-exception
(make-unsupported-grant-type grant-type)
(make-exception-with-message final-message)
(make-message-for-the-user final-user-message))))))
(let ((id-token
(issue <id-token>
issuer-key
#:webid webid
#:iss iss
#:aud client-id))
(access-token
(issue <access-token>
issuer-key
#:webid webid
#:iss iss
#:client-key (jwk dpop)
#:client-id client-id))
(refresh-token
(if (equal? grant-type "refresh_token")
(assoc-ref form-args "refresh_token")
(refresh:issue-refresh-token webid client-id
(jkt (jwk dpop))))))
(values
(build-response #:headers '((content-type application/json)
(cache-control (no-cache no-store)))
#:port #f)
(stubs:scm->json-string
`((id_token . ,id-token)
(access_token . ,access-token)
(token_type . "DPoP")
(expires_in . ,(p:oidc-token-default-validity))
(refresh_token . ,refresh-token)))
client-id
#f))))))))))
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