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

use std::{
    sync::Arc,
    time::{Duration, Instant},
};

use bson::rawdoc;
use serde::Deserialize;
use typed_builder::TypedBuilder;

use crate::{
    client::{
        auth::{
            sasl::{SaslResponse, SaslStart},
            AuthMechanism,
        },
        options::ServerApi,
    },
    cmap::Connection,
    error::{Error, Result},
};

use super::{sasl::SaslContinue, Credential, MONGODB_OIDC_STR};

/// The user-supplied callbacks for OIDC authentication.
#[derive(Clone)]
pub struct Callbacks {
    inner: Arc<CallbacksInner>,
}

pub type BoxFuture<'a, T> = std::pin::Pin<Box<dyn std::future::Future<Output = T> + Send + 'a>>;

impl Callbacks {
    /// Create a new instance with a token request callback.
    pub fn new<F>(on_request: F) -> Self
    where
        F: Fn(IdpServerInfo, RequestParameters) -> BoxFuture<'static, Result<IdpServerResponse>>
            + Send
            + Sync
            + 'static,
    {
        Self {
            inner: Arc::new(CallbacksInner {
                on_request: Box::new(on_request),
            }),
        }
    }
}

impl std::fmt::Debug for Callbacks {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("Callbacks").finish()
    }
}

struct CallbacksInner {
    on_request: Box<
        dyn Fn(IdpServerInfo, RequestParameters) -> BoxFuture<'static, Result<IdpServerResponse>>
            + Send
            + Sync,
    >,
    // on_refresh: Option<Box<dyn Fn(&IdpServerInfo) -> IdpServerResponse + Send + Sync>>,
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
#[non_exhaustive]
pub struct IdpServerInfo {
    pub issuer: String,
    pub client_id: String,
    pub request_scopes: Option<Vec<String>>,
}

#[derive(TypedBuilder)]
#[builder(field_defaults(setter(into)))]
#[non_exhaustive]
pub struct IdpServerResponse {
    pub access_token: String,
    pub expires: Option<Instant>,
    pub refresh_token: Option<String>,
}

#[derive(Debug)]
#[non_exhaustive]
pub struct RequestParameters {
    pub deadline: Instant,
}

pub(crate) async fn authenticate_stream(
    conn: &mut Connection,
    credential: &Credential,
    server_api: Option<&ServerApi>,
) -> Result<()> {
    let source = credential.source.as_deref().unwrap_or("$external");
    let callbacks = credential
        .oidc_callbacks
        .as_ref()
        .ok_or_else(|| auth_error("no callbacks supplied"))?
        .clone();

    let mut start_doc = rawdoc! {};
    if let Some(username) = credential.username.as_deref() {
        start_doc.append("n", username);
    }
    let sasl_start = SaslStart::new(
        source.to_string(),
        AuthMechanism::MongoDbOidc,
        start_doc.into_bytes(),
        server_api.cloned(),
    )
    .into_command();
    let response = send_sasl_command(conn, sasl_start).await?;
    if response.done {
        return Err(invalid_auth_response());
    }
    let idp_response = {
        let server_info: IdpServerInfo =
            bson::from_slice(&response.payload).map_err(|_| invalid_auth_response())?;
        const CALLBACK_TIMEOUT: Duration = Duration::from_secs(5 * 60);
        let cb_params = RequestParameters {
            deadline: Instant::now() + CALLBACK_TIMEOUT,
        };
        (callbacks.inner.on_request)(server_info, cb_params).await?
    };

    let sasl_continue = SaslContinue::new(
        source.to_string(),
        response.conversation_id,
        rawdoc! { "jwt": idp_response.access_token }.into_bytes(),
        server_api.cloned(),
    )
    .into_command();
    let response = send_sasl_command(conn, sasl_continue).await?;
    if !response.done {
        return Err(invalid_auth_response());
    }

    Ok(())
}

fn auth_error(s: impl AsRef<str>) -> Error {
    Error::authentication_error(MONGODB_OIDC_STR, s.as_ref())
}

fn invalid_auth_response() -> Error {
    Error::invalid_authentication_response(MONGODB_OIDC_STR)
}

async fn send_sasl_command(
    conn: &mut Connection,
    command: crate::cmap::Command,
) -> Result<SaslResponse> {
    let response = conn.send_command(command, None).await?;
    SaslResponse::parse(
        MONGODB_OIDC_STR,
        response.auth_response_body(MONGODB_OIDC_STR)?,
    )
}