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

// Copyright 2024 New Vector Ltd.
// Copyright 2021-2024 The Matrix.org Foundation C.I.C.
//
// SPDX-License-Identifier: AGPL-3.0-only
// Please see LICENSE in the repository root for full details.

use axum::{
    extract::State,
    response::{IntoResponse, Response},
    Json,
};
use hyper::StatusCode;
use mas_axum_utils::{
    jwt::JwtResponse,
    sentry::SentryEventID,
    user_authorization::{AuthorizationVerificationError, UserAuthorization},
};
use mas_jose::{
    constraints::Constrainable,
    jwt::{JsonWebSignatureHeader, Jwt},
};
use mas_keystore::Keystore;
use mas_router::UrlBuilder;
use mas_storage::{
    oauth2::OAuth2ClientRepository, user::UserEmailRepository, BoxClock, BoxRepository, BoxRng,
};
use oauth2_types::scope;
use serde::Serialize;
use serde_with::skip_serializing_none;
use thiserror::Error;

use crate::{impl_from_error_for_route, BoundActivityTracker};

#[skip_serializing_none]
#[derive(Serialize)]
struct UserInfo {
    sub: String,
    username: String,
    email: Option<String>,
    email_verified: Option<bool>,
}

#[derive(Serialize)]
struct SignedUserInfo {
    iss: String,
    aud: String,
    #[serde(flatten)]
    user_info: UserInfo,
}

#[derive(Debug, Error)]
pub enum RouteError {
    #[error(transparent)]
    Internal(Box<dyn std::error::Error + Send + Sync + 'static>),

    #[error("failed to authenticate")]
    AuthorizationVerificationError(
        #[from] AuthorizationVerificationError<mas_storage::RepositoryError>,
    ),

    #[error("session is not allowed to access the userinfo endpoint")]
    Unauthorized,

    #[error("no suitable key found for signing")]
    InvalidSigningKey,

    #[error("failed to load client")]
    NoSuchClient,

    #[error("failed to load user")]
    NoSuchUser,
}

impl_from_error_for_route!(mas_storage::RepositoryError);
impl_from_error_for_route!(mas_keystore::WrongAlgorithmError);
impl_from_error_for_route!(mas_jose::jwt::JwtSignatureError);

impl IntoResponse for RouteError {
    fn into_response(self) -> axum::response::Response {
        let event_id = sentry::capture_error(&self);
        let response = match self {
            Self::Internal(_) | Self::InvalidSigningKey | Self::NoSuchClient | Self::NoSuchUser => {
                (StatusCode::INTERNAL_SERVER_ERROR, self.to_string()).into_response()
            }
            Self::AuthorizationVerificationError(_) | Self::Unauthorized => {
                StatusCode::UNAUTHORIZED.into_response()
            }
        };

        (SentryEventID::from(event_id), response).into_response()
    }
}

#[tracing::instrument(name = "handlers.oauth2.userinfo.get", skip_all, err)]
pub async fn get(
    mut rng: BoxRng,
    clock: BoxClock,
    State(url_builder): State<UrlBuilder>,
    activity_tracker: BoundActivityTracker,
    mut repo: BoxRepository,
    State(key_store): State<Keystore>,
    user_authorization: UserAuthorization,
) -> Result<Response, RouteError> {
    let session = user_authorization.protected(&mut repo, &clock).await?;

    // This endpoint requires the `openid` scope.
    if !session.scope.contains("openid") {
        return Err(RouteError::Unauthorized);
    }

    // Fail if the session is not associated with a user.
    let Some(user_id) = session.user_id else {
        return Err(RouteError::Unauthorized);
    };

    activity_tracker
        .record_oauth2_session(&clock, &session)
        .await;

    let user = repo
        .user()
        .lookup(user_id)
        .await?
        .ok_or(RouteError::NoSuchUser)?;

    let user_email = if session.scope.contains(&scope::EMAIL) {
        repo.user_email().get_primary(&user).await?
    } else {
        None
    };

    let user_info = UserInfo {
        sub: user.sub.clone(),
        username: user.username.clone(),
        email_verified: user_email.as_ref().map(|u| u.confirmed_at.is_some()),
        email: user_email.map(|u| u.email),
    };

    let client = repo
        .oauth2_client()
        .lookup(session.client_id)
        .await?
        .ok_or(RouteError::NoSuchClient)?;

    if let Some(alg) = client.userinfo_signed_response_alg {
        let key = key_store
            .signing_key_for_algorithm(&alg)
            .ok_or(RouteError::InvalidSigningKey)?;

        let signer = key.params().signing_key_for_alg(&alg)?;
        let header = JsonWebSignatureHeader::new(alg)
            .with_kid(key.kid().ok_or(RouteError::InvalidSigningKey)?);

        let user_info = SignedUserInfo {
            iss: url_builder.oidc_issuer().to_string(),
            aud: client.client_id,
            user_info,
        };

        let token = Jwt::sign_with_rng(&mut rng, header, user_info, &signer)?;
        Ok(JwtResponse(token).into_response())
    } else {
        Ok(Json(user_info).into_response())
    }
}