Ankur Mhatre
38c0a5f358
Three modules on Spring Boot 4.1.1 with Spring Authorization Server 7.1.1: the provider
itself, a relying party, and an API that trusts its tokens. Client registration, PKCE,
a custom consent page and token customisation, with profiles that make each failure
reproducible.
Every claim is backed by captured output in docs/output/as-*.txt, regenerated by
authorization-server/scripts/run-all.sh. Notable findings, verified against the jars:
- OAuth2AuthorizationServerConfiguration.applyDefaultSecurity(HttpSecurity) was deleted
in 7.0, and both configuration classes moved into spring-security-config
- ClientSettings.requireProofKey flipped from false to true, on the authorization server
(1.5.8 -> 7.1.1) and on the OAuth2 client (6.5.1 -> 7.1.1)
- requireProofKey(false) does not make PKCE optional for a public client; the code
verifier is that client's only authentication at the token endpoint
- MediaTypeRequestMatcher(TEXT_HTML) matches Accept: */*, so the token endpoint answers
API callers with 302 -> /login unless setIgnoredMediaTypes(ALL) is called
Also renames the repository to spring-auth-demo and cross-links the new chapter set from
the existing documentation.
124 lines
7.0 KiB
Plaintext
124 lines
7.0 KiB
Plaintext
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------------------------------------------------------------------
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== PKCE parameters (RFC 7636)
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------------------------------------------------------------------
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code_verifier 1cYLvhzx4gH7jAoNyYB34Nv0jcuHMVqDPC8fFzZBuyiaYeArg2yU_LJIC2BBR8x1 (64 chars)
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code_challenge vocXBOiUBp_mSdSMvkfZUMxcKHxo021R2rZ46NndJ7c
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code_challenge_method S256
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The verifier never leaves the client until the token request. The challenge is
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all the authorization request carries, and it is a one-way hash of the verifier.
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------------------------------------------------------------------
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== 1. Log in to the authorization server (browser session)
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------------------------------------------------------------------
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$ curl -c jar -d username=alice -d password=password -d _csrf=<token> http://localhost:9000/login
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HTTP/1.1 302
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Location: http://localhost:9000/
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------------------------------------------------------------------
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== 2. GET /oauth2/authorize (client=demo-spa)
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------------------------------------------------------------------
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$ curl -b jar 'http://localhost:9000/oauth2/authorize?response_type=code&client_id=demo-spa&redirect_uri=http%3A%2F%2F127.0.0.1%3A8080%2Fauthorized&scope=openid%20orders.read&state=xyz123&code_challenge=vocXBOiUBp_mSdSMvkfZUMxcKHxo021R2rZ46NndJ7c&code_challenge_method=S256'
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-> 302 http://127.0.0.1:8080/authorized?code=SEUTqNBFCouk0Ip0zD1IGctT21q8_hboy-3B5ofrsKPWUhZe43_dQ-mIhmSwgtHeHka6lyeow-SMgcVb4kLGCl0czBIt1tnbiMsJbNu3HLdW7M06FVrYILKrmJqGFsoE&state=xyz123
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------------------------------------------------------------------
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== 3. No consent page
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------------------------------------------------------------------
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The authorization endpoint went straight back to the client. Either consent is
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off for this client, or every requested scope was already approved.
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------------------------------------------------------------------
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== 5. The authorization code
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------------------------------------------------------------------
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code = SEUTqNBFCouk0Ip0zD1IGctT21q8_hboy-3B5ofrsKPWUhZe43_dQ-mIhmSwgtHeHka6lyeow-SMgcVb4kLGCl0czBIt1tnbiMsJbNu3HLdW7M06FVrYILKrmJqGFsoE
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state = xyz123 (the client's own value, returned untouched - compare it)
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------------------------------------------------------------------
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== 6a. Exchange the code WITHOUT the verifier
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------------------------------------------------------------------
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This is the request an attacker who stole the code can make.
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HTTP 401
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(empty response body)
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>>> Rejected. invalid_grant is deliberately vague: the server will not tell
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>>> a caller whether the code was wrong, expired, already used, or missing a
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>>> verifier, because each of those is information an attacker can use.
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Note: this consumed the code. Authorization codes are single-use, so the
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successful exchange below needs a fresh one.
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------------------------------------------------------------------
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== 6b. A fresh code, exchanged properly
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------------------------------------------------------------------
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fresh code = _TiGoBrAj3MPpOg3uoh76reyCg-YfoYTvHSraf-ljGyPjrPF6C0ccK_C4IG4oXjavEbTym0HttIURO7Mrt2U-YgBQ8Q_TSrgLgwpU357VYRtDm5rFdu4WVtET2Lt0YjB
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$ curl -d grant_type=authorization_code -d code=... -d code_verifier=... http://localhost:9000/oauth2/token
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HTTP 200
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{
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"access_token": "eyJraWQiOiJmMjgxYTNkYy0zZjlmLTRkMGItOTk1YS1iZmUwYzcwYTEwODEiLCJhbGciOiJSUzI1NiJ9.eyJzdWIiOiJhbGljZSIsImF1ZCI6Im9yZGVycy1hcGkiLCJuYmYiOjE3ODc1Mzg3NTksInNjb3BlIjpbIm9wZW5pZCIsIm9yZGVycy5yZWFkIl0sInJvbGVzIjpbIkFETUlOIiwiVVNFUiJdLCJpc3MiOiJodHRwOi8vbG9jYWxob3N0OjkwMDAiLCJleHAiOjE3ODc1MzkwNTksImlhdCI6MTc4NzUzODc1OSwianRpIjoiZGYxNzJlNTgtOGMxZi00NWVlLTlkZWEtMGE3OWQ2Y2NlMDU1IiwidGVuYW50IjoiYWNtZSJ9.TGm_0gOhoVk1mSX4YVVLA6iQp_bDFTvFAjE_1DFltFyg33FLdl7tV0Z97587SB40SgL53Vx5AUan0egPVzxZscsYwUHVxQgnXHsm0FFfIGywqccXNn2IDleUAoKtMF4Lz6oMwNc9lC6XU32UgeKGOweM_IamKcHox9GnY7q9M57nG6boOp89FZzGcYsgQ9zkbG0XvzfX3WY-FS7O5cFm8oF0b3duJ3Hb3nP8WN8VrUJdOTzuGRJC9dwxZV0Ss6sI5Z-tGr0uz_Kf0tYmJ-zlx21zh6pVKHwCEnaN6T9crl4qa784DFJlW9MA4NI_E6vXOfpHbAMyRHONSrdUAcTCtA",
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"scope": "openid orders.read",
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"id_token": "eyJraWQiOiJmMjgxYTNkYy0zZjlmLTRkMGItOTk1YS1iZmUwYzcwYTEwODEiLCJhbGciOiJSUzI1NiJ9.eyJzdWIiOiJhbGljZSIsImF1ZCI6ImRlbW8tc3BhIiwiYXpwIjoiZGVtby1zcGEiLCJhdXRoX3RpbWUiOjE3ODc1Mzg3NTgsImlzcyI6Imh0dHA6Ly9sb2NhbGhvc3Q6OTAwMCIsInByZWZlcnJlZF91c2VybmFtZSI6ImFsaWNlIiwiZXhwIjoxNzg3NTQwNTU5LCJpYXQiOjE3ODc1Mzg3NTksImp0aSI6ImE5NjFkNGJkLWIwNGUtNDc1Ni04N2JkLWE5ZjI4ZjkxMWM3NCIsInNpZCI6IkNlZlExc2ZTblJkRzBMZnY0SGdhX25iZ1pPckJiWTV6dzRwN2F4U1V1ZU0ifQ.o3-P70sm-3n2GST9kQdc0TMTazGy5vjbtO6RLdkrkbqpdz5bFmEwirdZ7ajymyutPHaGF1vGpq76fnSoBCADpNtfqNJsir8aUyKoqPxGw9HLRN_Ocky3rP-XuKAVSuaplrlEiIC6CKvwoX1oH7CnJqrI1362oLaza7ThriIyzJhArrmCIZsn7AR5h0gqFp-ivMnVgPSiRI9Gg_IpD8Jr1ZREPHo6z304vpwfTU9CJeHQb2k8wWueuJJVcjnd2hfVvqqkXX9nyIqiwy3TGG_3bbEtQ4yA4uhLACcH0E1KCtFIOFPcLujcwsNa0EnsO4OLB3w1teppZyK4vpIfGUSXcA",
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"token_type": "Bearer",
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"expires_in": 299
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}
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------------------------------------------------------------------
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== 7. The access token
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------------------------------------------------------------------
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{
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"alg": "RS256",
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"kid": "f281a3dc-3f9f-4d0b-995a-bfe0c70a1081"
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}
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{
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"aud": "orders-api",
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"exp": 1787539059,
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"iat": 1787538759,
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"iss": "http://localhost:9000",
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"jti": "df172e58-8c1f-45ee-9dea-0a79d6cce055",
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"nbf": 1787538759,
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"roles": [
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"ADMIN",
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"USER"
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],
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"scope": [
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"openid",
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"orders.read"
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],
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"sub": "alice",
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"tenant": "acme"
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}
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------------------------------------------------------------------
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== 8. The id_token - a different token, for a different audience
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------------------------------------------------------------------
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{
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"aud": "demo-spa",
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"auth_time": 1787538758,
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"azp": "demo-spa",
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"exp": 1787540559,
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"iat": 1787538759,
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"iss": "http://localhost:9000",
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"jti": "a961d4bd-b04e-4756-87bd-a9f28f911c74",
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"preferred_username": "alice",
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"sid": "CefQ1sfSnRdG0Lfv4Hga_nbgZOrBbY5zw4p7axSUueM",
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"sub": "alice"
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}
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aud is the CLIENT here, not the API. Sending this to a resource server is the
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classic mix-up: it verifies (same issuer, same key) and then fails the audience
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check, or worse, passes it if nobody checks audience.
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------------------------------------------------------------------
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== 9. Calling the resource server
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------------------------------------------------------------------
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GET /api/orders -> 200
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{"orders":[{"total":"42.00","id":1}],"subject":"alice","clientId":null,"scopes":["openid","orders.read"],"roles":["ADMIN","USER"],"tenant":"acme","audience":["orders-api"]}
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GET /api/admin -> 200
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{"authorities":["FactorGrantedAuthority [authority=FACTOR_BEARER, issuedAt=2026-08-24T02:32:39.220990600Z]","SCOPE_openid","ROLE_USER","SCOPE_orders.read","ROLE_ADMIN"],"message":"admin only"}
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------------------------------------------------------------------
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== 10. Sending the id_token instead
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------------------------------------------------------------------
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HTTP/1.1 401
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WWW-Authenticate: Bearer error="invalid_token", error_description="An error occurred while attempting to decode the Jwt: the required audience orders-api is missing", error_uri="https://tools.ietf.org/html/rfc6750#section-3.1", resource_metadata="http://localhost:8090/.well-known/oauth-protected-resource"
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