auth.rs

  1use crate::{
  2    db::{self, dev_server, AccessTokenId, Database, DevServerId, UserId},
  3    rpc::Principal,
  4    AppState, Error, Result,
  5};
  6use anyhow::{anyhow, Context};
  7use axum::{
  8    http::{self, Request, StatusCode},
  9    middleware::Next,
 10    response::IntoResponse,
 11};
 12use prometheus::{exponential_buckets, register_histogram, Histogram};
 13pub use rpc::auth::random_token;
 14use scrypt::{
 15    password_hash::{PasswordHash, PasswordVerifier},
 16    Scrypt,
 17};
 18use serde::{Deserialize, Serialize};
 19use sha2::Digest;
 20use std::sync::OnceLock;
 21use std::{sync::Arc, time::Instant};
 22use subtle::ConstantTimeEq;
 23
 24/// Validates the authorization header and adds an Extension<Principal> to the request.
 25/// Authorization: <user-id> <token>
 26///   <token> can be an access_token attached to that user, or an access token of an admin
 27///   or (in development) the string ADMIN:<config.api_token>.
 28/// Authorization: "dev-server-token" <token>
 29pub async fn validate_header<B>(mut req: Request<B>, next: Next<B>) -> impl IntoResponse {
 30    let mut auth_header = req
 31        .headers()
 32        .get(http::header::AUTHORIZATION)
 33        .and_then(|header| header.to_str().ok())
 34        .ok_or_else(|| {
 35            Error::Http(
 36                StatusCode::UNAUTHORIZED,
 37                "missing authorization header".to_string(),
 38            )
 39        })?
 40        .split_whitespace();
 41
 42    let state = req.extensions().get::<Arc<AppState>>().unwrap();
 43
 44    let first = auth_header.next().unwrap_or("");
 45    if first == "dev-server-token" {
 46        let dev_server_token = auth_header.next().ok_or_else(|| {
 47            Error::Http(
 48                StatusCode::BAD_REQUEST,
 49                "missing dev-server-token token in authorization header".to_string(),
 50            )
 51        })?;
 52        let dev_server = verify_dev_server_token(dev_server_token, &state.db)
 53            .await
 54            .map_err(|e| Error::Http(StatusCode::UNAUTHORIZED, format!("{}", e)))?;
 55
 56        req.extensions_mut()
 57            .insert(Principal::DevServer(dev_server));
 58        return Ok::<_, Error>(next.run(req).await);
 59    }
 60
 61    let user_id = UserId(first.parse().map_err(|_| {
 62        Error::Http(
 63            StatusCode::BAD_REQUEST,
 64            "missing user id in authorization header".to_string(),
 65        )
 66    })?);
 67
 68    let access_token = auth_header.next().ok_or_else(|| {
 69        Error::Http(
 70            StatusCode::BAD_REQUEST,
 71            "missing access token in authorization header".to_string(),
 72        )
 73    })?;
 74
 75    // In development, allow impersonation using the admin API token.
 76    // Don't allow this in production because we can't tell who is doing
 77    // the impersonating.
 78    let validate_result = if let (Some(admin_token), true) = (
 79        access_token.strip_prefix("ADMIN_TOKEN:"),
 80        state.config.is_development(),
 81    ) {
 82        Ok(VerifyAccessTokenResult {
 83            is_valid: state.config.api_token == admin_token,
 84            impersonator_id: None,
 85        })
 86    } else {
 87        verify_access_token(&access_token, user_id, &state.db).await
 88    };
 89
 90    if let Ok(validate_result) = validate_result {
 91        if validate_result.is_valid {
 92            let user = state
 93                .db
 94                .get_user_by_id(user_id)
 95                .await?
 96                .ok_or_else(|| anyhow!("user {} not found", user_id))?;
 97
 98            if let Some(impersonator_id) = validate_result.impersonator_id {
 99                let admin = state
100                    .db
101                    .get_user_by_id(impersonator_id)
102                    .await?
103                    .ok_or_else(|| anyhow!("user {} not found", impersonator_id))?;
104                req.extensions_mut()
105                    .insert(Principal::Impersonated { user, admin });
106            } else {
107                req.extensions_mut().insert(Principal::User(user));
108            };
109            return Ok::<_, Error>(next.run(req).await);
110        }
111    }
112
113    Err(Error::Http(
114        StatusCode::UNAUTHORIZED,
115        "invalid credentials".to_string(),
116    ))
117}
118
119const MAX_ACCESS_TOKENS_TO_STORE: usize = 8;
120
121#[derive(Serialize, Deserialize)]
122struct AccessTokenJson {
123    version: usize,
124    id: AccessTokenId,
125    token: String,
126}
127
128/// Creates a new access token to identify the given user. before returning it, you should
129/// encrypt it with the user's public key.
130pub async fn create_access_token(
131    db: &db::Database,
132    user_id: UserId,
133    impersonated_user_id: Option<UserId>,
134) -> Result<String> {
135    const VERSION: usize = 1;
136    let access_token = rpc::auth::random_token();
137    let access_token_hash = hash_access_token(&access_token);
138    let id = db
139        .create_access_token(
140            user_id,
141            impersonated_user_id,
142            &access_token_hash,
143            MAX_ACCESS_TOKENS_TO_STORE,
144        )
145        .await?;
146    Ok(serde_json::to_string(&AccessTokenJson {
147        version: VERSION,
148        id,
149        token: access_token,
150    })?)
151}
152
153/// Hashing prevents anyone with access to the database being able to login.
154/// As the token is randomly generated, we don't need to worry about scrypt-style
155/// protection.
156pub fn hash_access_token(token: &str) -> String {
157    let digest = sha2::Sha256::digest(token);
158    format!(
159        "$sha256${}",
160        base64::encode_config(digest, base64::URL_SAFE)
161    )
162}
163
164/// Encrypts the given access token with the given public key to avoid leaking it on the way
165/// to the client.
166pub fn encrypt_access_token(access_token: &str, public_key: String) -> Result<String> {
167    let native_app_public_key =
168        rpc::auth::PublicKey::try_from(public_key).context("failed to parse app public key")?;
169    let encrypted_access_token = native_app_public_key
170        .encrypt_string(access_token)
171        .context("failed to encrypt access token with public key")?;
172    Ok(encrypted_access_token)
173}
174
175pub struct VerifyAccessTokenResult {
176    pub is_valid: bool,
177    pub impersonator_id: Option<UserId>,
178}
179
180/// Checks that the given access token is valid for the given user.
181pub async fn verify_access_token(
182    token: &str,
183    user_id: UserId,
184    db: &Arc<Database>,
185) -> Result<VerifyAccessTokenResult> {
186    static METRIC_ACCESS_TOKEN_HASHING_TIME: OnceLock<Histogram> = OnceLock::new();
187    let metric_access_token_hashing_time = METRIC_ACCESS_TOKEN_HASHING_TIME.get_or_init(|| {
188        register_histogram!(
189            "access_token_hashing_time",
190            "time spent hashing access tokens",
191            exponential_buckets(10.0, 2.0, 10).unwrap(),
192        )
193        .unwrap()
194    });
195
196    let token: AccessTokenJson = serde_json::from_str(&token)?;
197
198    let db_token = db.get_access_token(token.id).await?;
199    let token_user_id = db_token.impersonated_user_id.unwrap_or(db_token.user_id);
200    if token_user_id != user_id {
201        return Err(anyhow!("no such access token"))?;
202    }
203    let t0 = Instant::now();
204
205    let is_valid = if db_token.hash.starts_with("$scrypt$") {
206        let db_hash = PasswordHash::new(&db_token.hash).map_err(anyhow::Error::new)?;
207        Scrypt
208            .verify_password(token.token.as_bytes(), &db_hash)
209            .is_ok()
210    } else {
211        let token_hash = hash_access_token(&token.token);
212        db_token.hash.as_bytes().ct_eq(token_hash.as_ref()).into()
213    };
214
215    let duration = t0.elapsed();
216    log::info!("hashed access token in {:?}", duration);
217    metric_access_token_hashing_time.observe(duration.as_millis() as f64);
218
219    if is_valid && db_token.hash.starts_with("$scrypt$") {
220        let new_hash = hash_access_token(&token.token);
221        db.update_access_token_hash(db_token.id, &new_hash).await?;
222    }
223
224    Ok(VerifyAccessTokenResult {
225        is_valid,
226        impersonator_id: if db_token.impersonated_user_id.is_some() {
227            Some(db_token.user_id)
228        } else {
229            None
230        },
231    })
232}
233
234pub fn generate_dev_server_token(id: usize, access_token: String) -> String {
235    format!("{}.{}", id, access_token)
236}
237
238pub async fn verify_dev_server_token(
239    dev_server_token: &str,
240    db: &Arc<Database>,
241) -> anyhow::Result<dev_server::Model> {
242    let (id, token) = split_dev_server_token(dev_server_token)?;
243    let token_hash = hash_access_token(&token);
244    let server = db.get_dev_server(id).await?;
245
246    if server
247        .hashed_token
248        .as_bytes()
249        .ct_eq(token_hash.as_ref())
250        .into()
251    {
252        Ok(server)
253    } else {
254        Err(anyhow!("wrong token for dev server"))
255    }
256}
257
258// a dev_server_token has the format <id>.<base64>. This is to make them
259// relatively easy to copy/paste around.
260pub fn split_dev_server_token(dev_server_token: &str) -> anyhow::Result<(DevServerId, &str)> {
261    let mut parts = dev_server_token.splitn(2, '.');
262    let id = DevServerId(parts.next().unwrap_or_default().parse()?);
263    let token = parts
264        .next()
265        .ok_or_else(|| anyhow!("invalid dev server token format"))?;
266    Ok((id, token))
267}
268
269#[cfg(test)]
270mod test {
271    use rand::thread_rng;
272    use scrypt::password_hash::{PasswordHasher, SaltString};
273    use sea_orm::EntityTrait;
274
275    use super::*;
276    use crate::db::{access_token, NewUserParams};
277
278    #[gpui::test]
279    async fn test_verify_access_token(cx: &mut gpui::TestAppContext) {
280        let test_db = crate::db::TestDb::sqlite(cx.executor().clone());
281        let db = test_db.db();
282
283        let user = db
284            .create_user(
285                "example@example.com",
286                false,
287                NewUserParams {
288                    github_login: "example".into(),
289                    github_user_id: 1,
290                },
291            )
292            .await
293            .unwrap();
294
295        let token = create_access_token(&db, user.user_id, None).await.unwrap();
296        assert!(matches!(
297            verify_access_token(&token, user.user_id, &db)
298                .await
299                .unwrap(),
300            VerifyAccessTokenResult {
301                is_valid: true,
302                impersonator_id: None,
303            }
304        ));
305
306        let old_token = create_previous_access_token(user.user_id, None, &db)
307            .await
308            .unwrap();
309
310        let old_token_id = serde_json::from_str::<AccessTokenJson>(&old_token)
311            .unwrap()
312            .id;
313
314        let hash = db
315            .transaction(|tx| async move {
316                Ok(access_token::Entity::find_by_id(old_token_id)
317                    .one(&*tx)
318                    .await?)
319            })
320            .await
321            .unwrap()
322            .unwrap()
323            .hash;
324        assert!(hash.starts_with("$scrypt$"));
325
326        assert!(matches!(
327            verify_access_token(&old_token, user.user_id, &db)
328                .await
329                .unwrap(),
330            VerifyAccessTokenResult {
331                is_valid: true,
332                impersonator_id: None,
333            }
334        ));
335
336        let hash = db
337            .transaction(|tx| async move {
338                Ok(access_token::Entity::find_by_id(old_token_id)
339                    .one(&*tx)
340                    .await?)
341            })
342            .await
343            .unwrap()
344            .unwrap()
345            .hash;
346        assert!(hash.starts_with("$sha256$"));
347
348        assert!(matches!(
349            verify_access_token(&old_token, user.user_id, &db)
350                .await
351                .unwrap(),
352            VerifyAccessTokenResult {
353                is_valid: true,
354                impersonator_id: None,
355            }
356        ));
357
358        assert!(matches!(
359            verify_access_token(&token, user.user_id, &db)
360                .await
361                .unwrap(),
362            VerifyAccessTokenResult {
363                is_valid: true,
364                impersonator_id: None,
365            }
366        ));
367    }
368
369    async fn create_previous_access_token(
370        user_id: UserId,
371        impersonated_user_id: Option<UserId>,
372        db: &Database,
373    ) -> Result<String> {
374        let access_token = rpc::auth::random_token();
375        let access_token_hash = previous_hash_access_token(&access_token)?;
376        let id = db
377            .create_access_token(
378                user_id,
379                impersonated_user_id,
380                &access_token_hash,
381                MAX_ACCESS_TOKENS_TO_STORE,
382            )
383            .await?;
384        Ok(serde_json::to_string(&AccessTokenJson {
385            version: 1,
386            id,
387            token: access_token,
388        })?)
389    }
390
391    fn previous_hash_access_token(token: &str) -> Result<String> {
392        // Avoid slow hashing in debug mode.
393        let params = if cfg!(debug_assertions) {
394            scrypt::Params::new(1, 1, 1).unwrap()
395        } else {
396            scrypt::Params::new(14, 8, 1).unwrap()
397        };
398
399        Ok(Scrypt
400            .hash_password(
401                token.as_bytes(),
402                None,
403                params,
404                &SaltString::generate(thread_rng()),
405            )
406            .map_err(anyhow::Error::new)?
407            .to_string())
408    }
409}