Implement federated login; #123

rc_core/src/persist/user/federation.rs

@@ -1,5 +1,12 @@
+use openidconnect::{OAuth2TokenResponse, TokenResponse};
 use serde::{Serialize, Deserialize};
 
+const SOCIETY_URLS_API_ENDPOINT: &'static str = "api/v1/services.json";
+const ACCESS_CODE_AAD: &'static [u8] = b"oj-access-code";
+
+pub type DiscoveryMetadata = openidconnect::core::CoreProviderMetadata;
+pub type TokenResponsePayload = openidconnect::core::CoreTokenResponse;
+
 #[derive(Serialize, Deserialize, Clone, Debug)]
 pub struct Federation {
     pub enabled: bool,
@@ -14,3 +21,557 @@ impl std::default::Default for Federation {
         }
     }
 }
+
+#[derive(Serialize, Deserialize, Clone)]
+pub struct FederatedAuthenticationPayload {
+    pub display_name: String,
+    pub password: String,
+    pub domain_source: String,
+    pub domain_target: String,
+}
+
+#[derive(Deserialize, Serialize)]
+struct AccessCode {
+    aud: String,
+    exp: i64,
+    iat: i64,
+    iss: String,
+    sub: String,
+    secured: String,
+}
+
+#[derive(Deserialize, Serialize)]
+struct SecuredCodes {
+    access_token: String,
+    refresh_token: String,
+    code_challenge: String,
+}
+
+struct NonceProvider {
+    issuer: std::sync::Arc<String>,
+    secret: std::sync::Arc<Vec<u8>>,
+    generated_time: i64,
+    fuse: bool,
+}
+
+impl NonceProvider {
+    fn reset(&mut self, iat: i64) {
+        self.generated_time = iat;
+        self.fuse = false;
+    }
+}
+
+impl ring::aead::NonceSequence for NonceProvider {
+    // realistically this shouldn't ever be called again
+    fn advance(&mut self) -> Result<ring::aead::Nonce, ring::error::Unspecified> {
+        if self.fuse {
+            Err(ring::error::Unspecified)
+        } else {
+            use sha2::Digest;
+            self.fuse = true;
+            let hash = sha2::Sha512::new()
+                .chain_update(self.issuer.as_bytes())
+                .chain_update(self.secret.as_slice())
+                .chain_update(&self.generated_time.to_ne_bytes())
+                .finalize();
+            let mut nonce = Vec::from(hash.as_slice());
+            nonce.truncate(12);
+            Ok(ring::aead::Nonce::try_assume_unique_for_key(&nonce).unwrap())
+        }
+    }
+}
+
+impl super::AccountProvider {
+    fn nonce_provider(&self) -> NonceProvider {
+        NonceProvider {
+            issuer: self.auth.clone(),
+            secret: self.secret.clone(),
+            generated_time: 0,
+            fuse: true,
+        }
+    }
+
+    fn is_defederated_from(&self, domain: &str, fedi_conf: &crate::persist::config::Federation) -> bool {
+        for defederated in fedi_conf.defederated.iter() {
+            if domain.ends_with(defederated) {
+                return true;
+            }
+        }
+        false
+    }
+
+    async fn local_login_impl(&self, auth_info: super::FederatedAuthInfo, federation: &Option<crate::persist::config::Federation>) -> Result<super::UserLoginInfo, super::AuthError> {
+        if auth_info.display_name.is_empty() {
+            return Err(super::AuthError {
+                message: format!("Refusing federation login with empty username"),
+                code: crate::data::error_codes::AuthErrorCode::InvalidDisplayName,
+            });
+        }
+        if let Some(fedi_conf) = federation {
+            if auth_info.domain.is_empty() {
+                return Err(super::AuthError {
+                    message: format!("Refusing federation login with empty domain for logging in {}", auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::PasswordInvalidated,
+                });
+            }
+            let sanitised_domain = auth_info.domain.trim().to_lowercase();
+            let target_domain = if let Some(alias) = fedi_conf.aliases.get(&sanitised_domain) {
+                alias.to_owned()
+            } else {
+                sanitised_domain
+            };
+            if self.is_defederated_from(&target_domain, fedi_conf) {
+                return Err(super::AuthError {
+                    message: format!("Refusing federation with {} for logging in {}", auth_info.domain, auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::PasswordInvalidated,
+                });
+            }
+            let is_localhost = target_domain == "localhost"
+                || target_domain == "::1"
+                || target_domain == "0:0:0:0:0:0:0:1"
+                || target_domain.starts_with("127.0.0.")
+                || target_domain.starts_with("localhost:");
+            // TODO contact other domain
+            let social_urls_api = if is_localhost {
+                format!("http://{}/{}", target_domain, SOCIETY_URLS_API_ENDPOINT)
+            } else {
+                format!("https://{}/{}", target_domain, SOCIETY_URLS_API_ENDPOINT)
+            };
+            let urls: oj_serdes::society::ServiceDomains = self.intercom_http_client.get(&social_urls_api).send().await
+                .map_err(|e| {
+                    log::error!("Failed to get {}: {}", social_urls_api, e);
+                    super::AuthError {
+                        message: format!("Failed to get {} for logging in {}", social_urls_api, auth_info.display_name),
+                        code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                    }
+                })?
+                .json().await
+                .map_err(|e| {
+                    log::error!("Failed to deserialize {}: {}", social_urls_api, e);
+                    super::AuthError {
+                        message: format!("Failed to deserialize {} for logging in {}", social_urls_api, auth_info.display_name),
+                        code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                    }
+                })?;
+            if self.is_defederated_from(&urls.root, fedi_conf) {
+                return Err(super::AuthError {
+                    message: format!("Refusing federation with root {} for logging in {}", urls.root, auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::PasswordInvalidated,
+                });
+            }
+            let sani_soc = urls.society.trim_start_matches("http://").trim_start_matches("https://").trim_matches('/').to_lowercase();
+            if sani_soc != target_domain {
+                return Err(super::AuthError {
+                    message: format!("Bad society federation with {} for logging in {}", target_domain, auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                });
+            }
+            let issuer_url = openidconnect::IssuerUrl::new(urls.auth.clone())
+                .map_err(|e| super::AuthError {
+                    message: format!("Failed to parse issuer url {} for logging in {}: {}", urls.auth, auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?;
+            // openidconnect relies on an old dependency
+            let oauth_http_client = openidconnect::reqwest::ClientBuilder::new()
+                // Following redirects opens the client up to SSRF vulnerabilities.
+                .redirect(openidconnect::reqwest::redirect::Policy::none())
+                .build()
+                .expect("Client should build");
+            // access openid discovery endpoint to self-configure
+            let provider_metadata = DiscoveryMetadata::discover_async(issuer_url, &oauth_http_client).await
+                .map_err(|e| super::AuthError {
+                    message: format!("Failed to discover OAuth on {} for logging in {}: {}", urls.auth, auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?;
+            let redirect_url_s = format!("http://{}/federation/redirect", self.domain);
+            let redirect_url = openidconnect::RedirectUrl::new(redirect_url_s.clone())
+                .map_err(|e| super::AuthError {
+                    message: format!("Failed to parse redirect url {} for logging in {}: {}", redirect_url_s, auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?;
+            // do oauth exchange
+            let oauth_client = openidconnect::core::CoreClient::from_provider_metadata(
+                provider_metadata,
+                openidconnect::ClientId::new(self.domain.to_string()),
+                None, // no client secret
+            ).set_redirect_uri(redirect_url);
+            let (pkce_challenge, pkce_verifier) = openidconnect::PkceCodeChallenge::new_random_sha256();
+            let (auth_url, csrf_token, _nonce) = oauth_client
+                .authorize_url(
+                    openidconnect::core::CoreAuthenticationFlow::AuthorizationCode,
+                    openidconnect::CsrfToken::new_random,
+                    openidconnect::Nonce::new_random,
+                )
+                .add_scope(openidconnect::Scope::new("read".to_string()))
+                .add_scope(openidconnect::Scope::new("federate".to_string()))
+                .set_pkce_challenge(pkce_challenge)
+                .url();
+            // bypass browser because we don't need to ask permission and there's no mechanism to open a browser
+            let remote_login = FederatedAuthenticationPayload {
+                display_name: auth_info.display_name.clone(),
+                password: auth_info.password.clone(),
+                domain_source: self.domain.to_string(),
+                domain_target: auth_info.domain.clone(),
+            };
+            let auth_resp = oauth_http_client.post(auth_url)
+                .form(&remote_login)
+                .send()
+                .await
+                .map_err(|e| super::AuthError {
+                    message: format!("Failed to authenticate federated login in for {}: {}", auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?;
+            let auth_redirected_url = if let Some(loc_header) = auth_resp.headers().get("location") {
+                let url = loc_header.to_str().map_err(|e| super::AuthError {
+                    message: format!("Failed to stringify location header for {}: {}", auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::InvalidDisplayName,
+                })?;
+                reqwest::Url::parse(url).map_err(|e| super::AuthError {
+                    message: format!("Failed to parse location URL for {}: {}", auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::InvalidDisplayName,
+                })?
+            } else {
+                return Err(super::AuthError {
+                    message: format!("Bad OAuth2 auth response from {} for logging in {} (missing location header)", target_domain, auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                });
+            };
+            //let auth_redirected_url = auth_resp.url();
+            log::debug!("OAuth auth response URL: {}", auth_redirected_url);
+            let mut query_map: std::collections::HashMap<_, _>  = auth_redirected_url.query_pairs().collect();
+            let auth_code = if let Some(auth_code) = query_map.remove("code") {
+                openidconnect::AuthorizationCode::new(auth_code.to_string())
+            } else {
+                return Err(super::AuthError {
+                    message: format!("Bad OAuth2 auth response from {} for logging in {} (missing code)", target_domain, auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                });
+            };
+            if let Some(state) = query_map.remove("state") {
+                if state != csrf_token.into_secret() {
+                    return Err(super::AuthError {
+                        message: format!("Bad OAuth2 auth response from {} for logging in {} (invalid state)", target_domain, auth_info.display_name),
+                        code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                    });
+                }
+            } else {
+                return Err(super::AuthError {
+                    message: format!("Bad OAuth2 auth response from {} for logging in {} (missing state)", target_domain, auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                });
+            };
+            let token_resp: TokenResponsePayload = oauth_client.exchange_code(auth_code)
+                .map_err(|e| super::AuthError {
+                    message: format!("Failed to exchange code for {}: {}", auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?
+                .set_pkce_verifier(pkce_verifier)
+                .request_async(&oauth_http_client).await
+                .map_err(|e| super::AuthError {
+                    message: format!("Failed to exchange code for {}: {}", auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?;
+            let _id_token = token_resp.id_token()
+                .ok_or_else(|| super::AuthError {
+                    message: format!("OAuth2 Token response missing ID token for {}", auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?;
+            // Don't verify since it's not using the openidconnect::core's signing algorithm
+            /*let id_token_verifier = oauth_client.id_token_verifier();
+            let claims = id_token.claims(&id_token_verifier, &nonce)
+                .map_err(|e| super::AuthError {
+                    message: format!("Failed to verify OAuth2 claims for {}: {}", auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?;
+            if let Some(expected_access_token_hash) = claims.access_token_hash() {
+                let actual_access_token_hash = openidconnect::AccessTokenHash::from_token(
+                    token_resp.access_token(),
+                    id_token.signing_alg().map_err(|e| super::AuthError {
+                        message: format!("Failed to verify OAuth2 signing algorithm for {}: {}", auth_info.display_name, e),
+                        code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                    })?,
+                    id_token.signing_key(&id_token_verifier).map_err(|e| super::AuthError {
+                        message: format!("Failed to verify OAuth2 signing key for {}: {}", auth_info.display_name, e),
+                        code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                    })?,
+                ).map_err(|e| super::AuthError {
+                    message: format!("Failed to verify OAuth2 access token for {}: {}", auth_info.display_name, e),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?;
+                if actual_access_token_hash != *expected_access_token_hash {
+                    return Err(super::AuthError {
+                        message: format!("Failed to verify OAuth2 access token for {} (no match)", auth_info.display_name),
+                        code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                    });
+                }
+            }*/
+            let refresh_token = token_resp.refresh_token()
+                .ok_or_else(|| super::AuthError {
+                    message: format!("OAuth2 Token response missing refresh token for {}", auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+                })?
+                .secret()
+                .to_owned();
+            let remote_token = token_resp.access_token().secret();
+            #[cfg(debug_assertions)]
+            log::debug!("User {} authenticated to {} with access token {}", auth_info.display_name, target_domain, remote_token);
+            // create/update federated user entry in DB
+            self.update_local_database(&auth_info, &urls).await.map_err(|e| super::AuthError {
+                message: format!("Failed to update DB entries for {}: {}", auth_info.display_name, e),
+                code: crate::data::error_codes::AuthErrorCode::Unknown,
+            })?;
+            // return local success token
+            let local_token = self.localify_token(remote_token)?;
+            Ok(super::UserLoginInfo {
+                response: libfj::robocraft::AuthenticationResponseInfo {
+                    token: local_token,
+                    refresh_token: refresh_token,
+                    refresh_token_expiry: "0".to_string(), // TODO (seems like this isn't actually considered by the client)
+                },
+                is_new: false,
+            })
+        } else {
+            Err(super::AuthError {
+                message: format!("Refusing federation with {} for logging in {} (federation not configured)", auth_info.domain, auth_info.display_name),
+                code: crate::data::error_codes::AuthErrorCode::PasswordInvalidated,
+            })
+        }
+    }
+
+    fn localify_token(&self, remote_token: &str) -> Result<String, super::AuthError> {
+        let remote_token_data = jsonwebtoken::dangerous::insecure_decode::<crate::auth::Token>(remote_token)
+            .map_err(|e| super::AuthError {
+                message: e.to_string(),
+                code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+            })?;
+        let local_token_data = crate::auth::Token {
+            iss: self.auth.to_string(),
+            fedi_token: Some(remote_token.to_owned()),
+            ..remote_token_data.claims
+        };
+        let header = jsonwebtoken::Header {
+            typ: Some("JWT".to_string()),
+            alg: jsonwebtoken::Algorithm::HS256,
+            ..Default::default()
+        };
+        let secret = jsonwebtoken::EncodingKey::from_secret(&self.secret);
+        let token = jsonwebtoken::encode(&header, &local_token_data, &secret)
+            .unwrap_or_else(|e| {
+                log::error!("Failed to encode fedi JWT: {}", e);
+                libfj::robocraft::DEFAULT_TOKEN.to_owned()
+            });
+        Ok(token)
+    }
+
+    async fn update_local_database(&self, auth_info: &super::FederatedAuthInfo, services_info: &oj_serdes::society::ServiceDomains) -> Result<(), oj_rc_database::sea_orm::DbErr> {
+        use oj_rc_database::sea_orm::IntoActiveModel;
+        let now = chrono::Utc::now().timestamp();
+        let fedi_id = if let Some(existing_fedi) = self.db.federation_by_domain(&services_info.root).await? {
+            let mut active = existing_fedi.into_active_model();
+            active.last_used_time = oj_rc_database::sea_orm::ActiveValue::Set(now);
+            active.auth = oj_rc_database::sea_orm::ActiveValue::Set(services_info.auth.clone());
+            active.cdn = oj_rc_database::sea_orm::ActiveValue::Set(services_info.cdn.clone());
+            active.factory = oj_rc_database::sea_orm::ActiveValue::Set(services_info.factory.clone());
+            active.society = oj_rc_database::sea_orm::ActiveValue::Set(services_info.society.clone());
+            self.db.update_federation(active).await?.id
+        } else {
+            let new_entity = oj_rc_database::schema::federation::ActiveModel {
+                id: oj_rc_database::sea_orm::ActiveValue::NotSet,
+                creation_time: oj_rc_database::sea_orm::ActiveValue::Set(now),
+                last_used_time: oj_rc_database::sea_orm::ActiveValue::Set(now),
+                domain: oj_rc_database::sea_orm::ActiveValue::Set(services_info.root.clone()),
+                auth: oj_rc_database::sea_orm::ActiveValue::Set(services_info.auth.clone()),
+                cdn: oj_rc_database::sea_orm::ActiveValue::Set(services_info.cdn.clone()),
+                factory: oj_rc_database::sea_orm::ActiveValue::Set(services_info.factory.clone()),
+                society: oj_rc_database::sea_orm::ActiveValue::Set(services_info.society.clone()),
+            };
+            self.db.insert_federation(new_entity).await?.id
+        };
+        let qualified_name = format!("{}#{}", auth_info.display_name, services_info.root);
+        if let Some(existing_user) = self.db.user_by_display_name_and_federation(qualified_name.clone(), fedi_id).await? {
+            log::info!("Using existing federated user with id {} for {} from {}", existing_user.id, auth_info.display_name, auth_info.domain);
+        } else {
+            let new_id = super::initial_data::register_new_federated_user(auth_info, fedi_id, &qualified_name, self.db.as_ref()).await?;
+            log::info!("Created federated user with id {} for {} from {}", new_id, auth_info.display_name, auth_info.domain);
+        }
+        Ok(())
+    }
+
+    async fn remote_auth_impl(&self, auth_info: &FederatedAuthenticationPayload, challenge: &str, federation: &Option<crate::persist::config::Federation>) -> Result<String, super::AuthError> {
+        if auth_info.display_name.is_empty() {
+            return Err(super::AuthError {
+                message: format!("Refusing federation login with empty username"),
+                code: crate::data::error_codes::AuthErrorCode::InvalidDisplayName,
+            });
+        }
+        if let Some(fedi_conf) = federation {
+            if auth_info.domain_source.is_empty() {
+                return Err(super::AuthError {
+                    message: format!("Refusing federation login with empty domain_source"),
+                    code: crate::data::error_codes::AuthErrorCode::InvalidDisplayName,
+                });
+            }
+            if auth_info.domain_target != *self.domain {
+                return Err(super::AuthError {
+                    message: format!("Refusing federation login with not my domain_target"),
+                    code: crate::data::error_codes::AuthErrorCode::InvalidDisplayName,
+                });
+            }
+            if self.is_defederated_from(&auth_info.domain_source, fedi_conf) {
+                return Err(super::AuthError {
+                    message: format!("Refusing federation with {} for logging in {}", auth_info.domain_source, auth_info.display_name),
+                    code: crate::data::error_codes::AuthErrorCode::PasswordInvalidated,
+                });
+            }
+            let user_info = super::UserAuthInfo::Username {
+                username: auth_info.display_name.clone(),
+                password: auth_info.password.clone(),
+            };
+            let login_info = self.login_internal(user_info, Some(auth_info.domain_source.clone())).await?;
+            Ok(Self::generate_access_code(
+                &*self.auth,
+                challenge,
+                &auth_info.display_name,
+                &login_info.response.token,
+                &login_info.response.refresh_token,
+                &*self.secret,
+                self.nonce_provider(),
+            ))
+        } else {
+            Err(super::AuthError {
+                message: format!("Refusing federation with {} for logging in {} (federation not configured)", auth_info.domain_source, auth_info.display_name),
+                code: crate::data::error_codes::AuthErrorCode::PasswordInvalidated,
+            })
+        }
+    }
+
+    async fn remote_token_impl(&self, access_code: &str, verifier: &str) -> Result<super::UserLoginInfo, super::AuthError> {
+        let (_code, tokens) = Self::read_access_code(access_code, &self.auth, &self.secret, self.nonce_provider())
+            .map_err(|_| super::AuthError {
+                message: "Failed to read access code".to_owned(),
+                code: crate::data::error_codes::AuthErrorCode::BadCredentials,
+            })?;
+        if !Self::validate_pkce(&tokens.code_challenge, verifier) {
+            return Err(super::AuthError {
+                message: "Failed to validate PKCE".to_owned(),
+                code: crate::data::error_codes::AuthErrorCode::AccountUnconfirmed,
+            });
+        }
+        Ok(super::UserLoginInfo {
+            response: libfj::robocraft::AuthenticationResponseInfo {
+                token: tokens.access_token,
+                refresh_token: tokens.refresh_token,
+                refresh_token_expiry: "0".to_owned(), // TODO
+            },
+            is_new: false,
+        })
+    }
+
+    fn build_key(secret: &[u8], issuer: &str) -> Vec<u8> {
+        if secret.len() < 32 {
+            let mut temp_key = Vec::from(secret);
+            for b in issuer.bytes() {
+                temp_key.push(b);
+                if temp_key.len() >= 32 {
+                    break;
+                }
+            }
+            if temp_key.len() < 32 {
+                for _ in temp_key.len()..32 {
+                    temp_key.push(0);
+                }
+            }
+            temp_key
+        } else if secret.len() > 32 {
+            let mut temp_key = Vec::from(secret);
+            temp_key.truncate(32);
+            temp_key
+        } else {
+            Vec::from(secret)
+        }
+    }
+
+    fn generate_access_code(issuer: &str, challenge: &str, display_name: &str, access_token: &str, refresh_token: &str, secret: &[u8], mut noncer: NonceProvider) -> String {
+        use ring::aead::BoundKey;
+        use base64::Engine;
+        let now = chrono::Utc::now().timestamp();
+        noncer.reset(now);
+        let secure_data = SecuredCodes {
+            access_token: access_token.to_owned(),
+            refresh_token: refresh_token.to_owned(),
+            code_challenge: challenge.to_owned(),
+        };
+        let secure_data_str = serde_json::to_string(&secure_data).unwrap();
+        let key = Self::build_key(secret, issuer);
+        let enc_key = ring::aead::UnboundKey::new(&ring::aead::AES_256_GCM, &key).unwrap();
+        let mut seal_key = ring::aead::SealingKey::new(enc_key, noncer);
+        let mut enc_data = Vec::from(secure_data_str.as_bytes());
+        seal_key.seal_in_place_append_tag(ring::aead::Aad::from(ACCESS_CODE_AAD), &mut enc_data).unwrap();
+        let secured_b64 = base64::engine::general_purpose::STANDARD.encode(enc_data);
+        let token_data = AccessCode {
+            aud: issuer.to_owned(),
+            exp: now + 60, // 60s
+            iat: now,
+            iss: issuer.to_owned(),
+            sub: display_name.to_owned(),
+            secured: secured_b64,
+        };
+        let data_str = serde_json::to_string(&token_data).unwrap();
+        base64::engine::general_purpose::URL_SAFE_NO_PAD.encode(data_str)
+    }
+
+    fn read_access_code(code: &str, issuer: &str, secret: &[u8], mut noncer: NonceProvider) -> Result<(AccessCode, SecuredCodes), ()> {
+        use ring::aead::BoundKey;
+        use base64::Engine;
+        let json_bytes = base64::engine::general_purpose::URL_SAFE_NO_PAD.decode(code)
+            .map_err(|e| {
+                log::error!("Failed to decode Base64 access code: {}", e);
+            })?;
+        let access_code: AccessCode = serde_json::from_slice(&json_bytes)
+            .map_err(|e| {
+                log::error!("Failed to decode JSON access code: {}", e);
+            })?;
+        let mut enc_data = base64::engine::general_purpose::STANDARD.decode(&access_code.secured)
+            .map_err(|e| {
+                log::error!("Failed to decode Base64 secure code: {}", e);
+            })?;
+        noncer.reset(access_code.iat);
+        let key = Self::build_key(secret, issuer);
+        let enc_key = ring::aead::UnboundKey::new(&ring::aead::AES_256_GCM, &key).unwrap();
+        let mut opening_key = ring::aead::OpeningKey::new(enc_key, noncer);
+        let plaintext = opening_key.open_in_place(ring::aead::Aad::from(ACCESS_CODE_AAD), &mut enc_data)
+            .map_err(|e| {
+                log::error!("Failed to decrypt secure code: {}", e);
+            })?;
+        let secure_data: SecuredCodes = serde_json::from_slice(&plaintext)
+            .map_err(|e| {
+                log::error!("Failed to decode JSON secure code: {}", e);
+            })?;
+        Ok((access_code, secure_data))
+    }
+
+    fn validate_pkce(challenge: &str, verifier: &str) -> bool {
+        use sha2::Digest;
+        use base64::Engine;
+        let hash = sha2::Sha256::new()
+            .chain_update(verifier.as_bytes())
+            .finalize();
+        let expected = base64::engine::general_purpose::URL_SAFE_NO_PAD.encode(hash);
+        expected == challenge
+    }
+}
+
+#[async_trait::async_trait]
+impl super::FederatedAuthenticator for super::AccountProvider {
+    async fn local_login(&self, info: super::FederatedAuthInfo) -> Result<super::UserLoginInfo, super::AuthError> {
+        self.local_login_impl(info, &self.federation).await
+    }
+
+    async fn remote_auth(&self, info: &FederatedAuthenticationPayload, challenge: &str) -> Result<String, super::AuthError> {
+        self.remote_auth_impl(info, challenge, &self.federation).await
+    }
+
+    async fn remote_token(&self, access_code: &str, verifier: &str) -> Result<super::UserLoginInfo, super::AuthError> {
+        self.remote_token_impl(access_code, verifier).await
+    }
+}