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lewis.moe
1use reqwest::Client;
2use serde::{Deserialize, Serialize};
3use std::collections::HashMap;
4use std::sync::Arc;
5use tokio::sync::RwLock;
6
7use super::OAuthError;
8
9#[derive(Debug, Clone, Serialize, Deserialize)]
10pub struct ClientMetadata {
11 pub client_id: String,
12 #[serde(skip_serializing_if = "Option::is_none")]
13 pub client_name: Option<String>,
14 #[serde(skip_serializing_if = "Option::is_none")]
15 pub client_uri: Option<String>,
16 #[serde(skip_serializing_if = "Option::is_none")]
17 pub logo_uri: Option<String>,
18 pub redirect_uris: Vec<String>,
19 #[serde(default)]
20 pub grant_types: Vec<String>,
21 #[serde(default)]
22 pub response_types: Vec<String>,
23 #[serde(skip_serializing_if = "Option::is_none")]
24 pub scope: Option<String>,
25 #[serde(skip_serializing_if = "Option::is_none")]
26 pub token_endpoint_auth_method: Option<String>,
27 #[serde(skip_serializing_if = "Option::is_none")]
28 pub dpop_bound_access_tokens: Option<bool>,
29 #[serde(skip_serializing_if = "Option::is_none")]
30 pub jwks: Option<serde_json::Value>,
31 #[serde(skip_serializing_if = "Option::is_none")]
32 pub jwks_uri: Option<String>,
33 #[serde(skip_serializing_if = "Option::is_none")]
34 pub application_type: Option<String>,
35}
36
37impl Default for ClientMetadata {
38 fn default() -> Self {
39 Self {
40 client_id: String::new(),
41 client_name: None,
42 client_uri: None,
43 logo_uri: None,
44 redirect_uris: Vec::new(),
45 grant_types: vec!["authorization_code".to_string()],
46 response_types: vec!["code".to_string()],
47 scope: None,
48 token_endpoint_auth_method: Some("none".to_string()),
49 dpop_bound_access_tokens: None,
50 jwks: None,
51 jwks_uri: None,
52 application_type: None,
53 }
54 }
55}
56
57#[derive(Clone)]
58pub struct ClientMetadataCache {
59 cache: Arc<RwLock<HashMap<String, CachedMetadata>>>,
60 jwks_cache: Arc<RwLock<HashMap<String, CachedJwks>>>,
61 http_client: Client,
62 cache_ttl_secs: u64,
63}
64
65struct CachedMetadata {
66 metadata: ClientMetadata,
67 cached_at: std::time::Instant,
68}
69
70struct CachedJwks {
71 jwks: serde_json::Value,
72 cached_at: std::time::Instant,
73}
74
75impl ClientMetadataCache {
76 pub fn new(cache_ttl_secs: u64) -> Self {
77 Self {
78 cache: Arc::new(RwLock::new(HashMap::new())),
79 jwks_cache: Arc::new(RwLock::new(HashMap::new())),
80 http_client: Client::builder()
81 .timeout(std::time::Duration::from_secs(30))
82 .connect_timeout(std::time::Duration::from_secs(10))
83 .pool_max_idle_per_host(10)
84 .pool_idle_timeout(std::time::Duration::from_secs(90))
85 .user_agent("Tranquil-PDS/1.0 (ATProto; +https://tangled.org/lewis.moe/bspds-sandbox)")
86 .build()
87 .unwrap_or_else(|_| Client::new()),
88 cache_ttl_secs,
89 }
90 }
91
92 fn is_loopback_client(client_id: &str) -> bool {
93 if let Ok(url) = reqwest::Url::parse(client_id) {
94 url.scheme() == "http"
95 && url.host_str() == Some("localhost")
96 && url.port().is_none()
97 // empty path
98 && url.path() == "/"
99 } else {
100 false
101 }
102 }
103
104 fn build_loopback_metadata(client_id: &str) -> Result<ClientMetadata, OAuthError> {
105 let url = reqwest::Url::parse(client_id)
106 .map_err(|_| OAuthError::InvalidClient("Invalid loopback client_id URL".into()))?;
107 let mut redirect_uris = Vec::<String>::new();
108 let mut scope: Option<String> = None;
109 for (key, value) in url.query_pairs() {
110 if key == "redirect_uri" {
111 redirect_uris.push(value.to_string());
112 break;
113 }
114 if key == "scope" {
115 scope = Some(value.into());
116 break;
117 }
118 }
119 if redirect_uris.is_empty() {
120 redirect_uris.push("http://127.0.0.1/".into());
121 redirect_uris.push("http://[::1]/".into());
122 }
123 if scope.is_none() {
124 scope = Some("atproto".into());
125 }
126 Ok(ClientMetadata {
127 client_id: client_id.into(),
128 client_name: Some("Loopback Client".into()),
129 client_uri: None,
130 logo_uri: None,
131 redirect_uris,
132 grant_types: vec!["authorization_code".into(), "refresh_token".into()],
133 response_types: vec!["code".into()],
134 scope,
135 token_endpoint_auth_method: Some("none".into()),
136 dpop_bound_access_tokens: Some(false),
137 jwks: None,
138 jwks_uri: None,
139 application_type: Some("native".into()),
140 })
141 }
142
143 pub async fn get(&self, client_id: &str) -> Result<ClientMetadata, OAuthError> {
144 if Self::is_loopback_client(client_id) {
145 return Self::build_loopback_metadata(client_id);
146 }
147 {
148 let cache = self.cache.read().await;
149 if let Some(cached) = cache.get(client_id)
150 && cached.cached_at.elapsed().as_secs() < self.cache_ttl_secs
151 {
152 return Ok(cached.metadata.clone());
153 }
154 }
155 let metadata = self.fetch_metadata(client_id).await?;
156 {
157 let mut cache = self.cache.write().await;
158 cache.insert(
159 client_id.to_string(),
160 CachedMetadata {
161 metadata: metadata.clone(),
162 cached_at: std::time::Instant::now(),
163 },
164 );
165 }
166 Ok(metadata)
167 }
168
169 pub async fn get_jwks(
170 &self,
171 metadata: &ClientMetadata,
172 ) -> Result<serde_json::Value, OAuthError> {
173 if let Some(jwks) = &metadata.jwks {
174 return Ok(jwks.clone());
175 }
176 let jwks_uri = metadata.jwks_uri.as_ref().ok_or_else(|| {
177 OAuthError::InvalidClient(
178 "Client using private_key_jwt must have jwks or jwks_uri".to_string(),
179 )
180 })?;
181 {
182 let cache = self.jwks_cache.read().await;
183 if let Some(cached) = cache.get(jwks_uri)
184 && cached.cached_at.elapsed().as_secs() < self.cache_ttl_secs
185 {
186 return Ok(cached.jwks.clone());
187 }
188 }
189 let jwks = self.fetch_jwks(jwks_uri).await?;
190 {
191 let mut cache = self.jwks_cache.write().await;
192 cache.insert(
193 jwks_uri.clone(),
194 CachedJwks {
195 jwks: jwks.clone(),
196 cached_at: std::time::Instant::now(),
197 },
198 );
199 }
200 Ok(jwks)
201 }
202
203 async fn fetch_jwks(&self, jwks_uri: &str) -> Result<serde_json::Value, OAuthError> {
204 if !jwks_uri.starts_with("https://")
205 && (!jwks_uri.starts_with("http://")
206 || (!jwks_uri.contains("localhost") && !jwks_uri.contains("127.0.0.1")))
207 {
208 return Err(OAuthError::InvalidClient(
209 "jwks_uri must use https (except for localhost)".to_string(),
210 ));
211 }
212 let response = self
213 .http_client
214 .get(jwks_uri)
215 .header("Accept", "application/json")
216 .send()
217 .await
218 .map_err(|e| {
219 OAuthError::InvalidClient(format!("Failed to fetch JWKS from {}: {}", jwks_uri, e))
220 })?;
221 if !response.status().is_success() {
222 return Err(OAuthError::InvalidClient(format!(
223 "Failed to fetch JWKS: HTTP {}",
224 response.status()
225 )));
226 }
227 let jwks: serde_json::Value = response
228 .json()
229 .await
230 .map_err(|e| OAuthError::InvalidClient(format!("Invalid JWKS JSON: {}", e)))?;
231 if jwks.get("keys").and_then(|k| k.as_array()).is_none() {
232 return Err(OAuthError::InvalidClient(
233 "JWKS must contain a 'keys' array".to_string(),
234 ));
235 }
236 Ok(jwks)
237 }
238
239 async fn fetch_metadata(&self, client_id: &str) -> Result<ClientMetadata, OAuthError> {
240 if !client_id.starts_with("http://") && !client_id.starts_with("https://") {
241 return Err(OAuthError::InvalidClient(
242 "client_id must be a URL".to_string(),
243 ));
244 }
245 if client_id.starts_with("http://")
246 && !client_id.contains("localhost")
247 && !client_id.contains("127.0.0.1")
248 {
249 return Err(OAuthError::InvalidClient(
250 "Non-localhost client_id must use https".to_string(),
251 ));
252 }
253 let response = self
254 .http_client
255 .get(client_id)
256 .header("Accept", "application/json")
257 .send()
258 .await
259 .map_err(|e| {
260 tracing::warn!(client_id = %client_id, error = %e, "Failed to fetch client metadata");
261 OAuthError::InvalidClient(format!("Failed to fetch client metadata: {}", e))
262 })?;
263 if !response.status().is_success() {
264 tracing::warn!(client_id = %client_id, status = %response.status(), "Failed to fetch client metadata");
265 return Err(OAuthError::InvalidClient(format!(
266 "Failed to fetch client metadata: HTTP {}",
267 response.status()
268 )));
269 }
270 let mut metadata: ClientMetadata = response.json().await.map_err(|e| {
271 OAuthError::InvalidClient(format!("Invalid client metadata JSON: {}", e))
272 })?;
273 if metadata.client_id.is_empty() {
274 metadata.client_id = client_id.to_string();
275 } else if metadata.client_id != client_id {
276 return Err(OAuthError::InvalidClient(
277 "client_id in metadata does not match request".to_string(),
278 ));
279 }
280 self.validate_metadata(&metadata)?;
281 Ok(metadata)
282 }
283
284 fn validate_metadata(&self, metadata: &ClientMetadata) -> Result<(), OAuthError> {
285 if metadata.redirect_uris.is_empty() {
286 return Err(OAuthError::InvalidClient(
287 "redirect_uris is required".to_string(),
288 ));
289 }
290 for uri in &metadata.redirect_uris {
291 self.validate_redirect_uri_format(uri)?;
292 }
293 if !metadata.grant_types.is_empty()
294 && !metadata
295 .grant_types
296 .contains(&"authorization_code".to_string())
297 {
298 return Err(OAuthError::InvalidClient(
299 "authorization_code grant type is required".to_string(),
300 ));
301 }
302 if !metadata.response_types.is_empty()
303 && !metadata.response_types.contains(&"code".to_string())
304 {
305 return Err(OAuthError::InvalidClient(
306 "code response type is required".to_string(),
307 ));
308 }
309 Ok(())
310 }
311
312 pub fn validate_redirect_uri(
313 &self,
314 metadata: &ClientMetadata,
315 redirect_uri: &str,
316 ) -> Result<(), OAuthError> {
317 if metadata.redirect_uris.contains(&redirect_uri.to_string()) {
318 return Ok(());
319 }
320 if Self::is_loopback_client(&metadata.client_id)
321 && let Ok(req_url) = reqwest::Url::parse(redirect_uri)
322 {
323 let req_host = req_url.host_str().unwrap_or("");
324 let is_loopback_redirect = req_url.scheme() == "http"
325 && (req_host == "localhost" || req_host == "127.0.0.1" || req_host == "[::1]");
326 if is_loopback_redirect {
327 return Ok(());
328 }
329 }
330 Err(OAuthError::InvalidRequest(
331 "redirect_uri not registered for client".to_string(),
332 ))
333 }
334
335 fn validate_redirect_uri_format(&self, uri: &str) -> Result<(), OAuthError> {
336 if uri.contains('#') {
337 return Err(OAuthError::InvalidClient(
338 "redirect_uri must not contain a fragment".to_string(),
339 ));
340 }
341 let parsed = reqwest::Url::parse(uri)
342 .map_err(|_| OAuthError::InvalidClient(format!("Invalid redirect_uri: {}", uri)))?;
343 let scheme = parsed.scheme();
344 if scheme == "http" {
345 let host = parsed.host_str().unwrap_or("");
346 if host != "localhost" && host != "127.0.0.1" && host != "[::1]" {
347 return Err(OAuthError::InvalidClient(
348 "http redirect_uri only allowed for localhost".to_string(),
349 ));
350 }
351 } else if scheme == "https" {
352 } else if scheme.chars().all(|c| {
353 c.is_ascii_lowercase() || c.is_ascii_digit() || c == '+' || c == '.' || c == '-'
354 }) {
355 if !scheme
356 .chars()
357 .next()
358 .map(|c| c.is_ascii_lowercase())
359 .unwrap_or(false)
360 {
361 return Err(OAuthError::InvalidClient(format!(
362 "Invalid redirect_uri scheme: {}",
363 scheme
364 )));
365 }
366 } else {
367 return Err(OAuthError::InvalidClient(format!(
368 "Invalid redirect_uri scheme: {}",
369 scheme
370 )));
371 }
372 Ok(())
373 }
374}
375
376impl ClientMetadata {
377 pub fn requires_dpop(&self) -> bool {
378 self.dpop_bound_access_tokens.unwrap_or(false)
379 }
380
381 pub fn auth_method(&self) -> &str {
382 self.token_endpoint_auth_method.as_deref().unwrap_or("none")
383 }
384}
385
386pub async fn verify_client_auth(
387 cache: &ClientMetadataCache,
388 metadata: &ClientMetadata,
389 client_auth: &super::ClientAuth,
390) -> Result<(), OAuthError> {
391 let expected_method = metadata.auth_method();
392 match (expected_method, client_auth) {
393 ("none", super::ClientAuth::None) => Ok(()),
394 ("none", _) => Err(OAuthError::InvalidClient(
395 "Client is configured for no authentication, but credentials were provided".to_string(),
396 )),
397 ("private_key_jwt", super::ClientAuth::PrivateKeyJwt { client_assertion }) => {
398 verify_private_key_jwt_async(cache, metadata, client_assertion).await
399 }
400 ("private_key_jwt", _) => Err(OAuthError::InvalidClient(
401 "Client requires private_key_jwt authentication".to_string(),
402 )),
403 ("client_secret_post", super::ClientAuth::SecretPost { .. }) => {
404 Err(OAuthError::InvalidClient(
405 "client_secret_post is not supported for ATProto OAuth".to_string(),
406 ))
407 }
408 ("client_secret_basic", super::ClientAuth::SecretBasic { .. }) => {
409 Err(OAuthError::InvalidClient(
410 "client_secret_basic is not supported for ATProto OAuth".to_string(),
411 ))
412 }
413 (method, _) => Err(OAuthError::InvalidClient(format!(
414 "Unsupported or mismatched authentication method: {}",
415 method
416 ))),
417 }
418}
419
420async fn verify_private_key_jwt_async(
421 cache: &ClientMetadataCache,
422 metadata: &ClientMetadata,
423 client_assertion: &str,
424) -> Result<(), OAuthError> {
425 use base64::{
426 Engine as _,
427 engine::general_purpose::{STANDARD, URL_SAFE_NO_PAD},
428 };
429 let parts: Vec<&str> = client_assertion.split('.').collect();
430 if parts.len() != 3 {
431 return Err(OAuthError::InvalidClient(
432 "Invalid client_assertion format".to_string(),
433 ));
434 }
435 let header_bytes = URL_SAFE_NO_PAD
436 .decode(parts[0])
437 .or_else(|_| STANDARD.decode(parts[0]))
438 .map_err(|_| OAuthError::InvalidClient("Invalid assertion header encoding".to_string()))?;
439 let header: serde_json::Value = serde_json::from_slice(&header_bytes)
440 .map_err(|_| OAuthError::InvalidClient("Invalid assertion header JSON".to_string()))?;
441 let alg = header
442 .get("alg")
443 .and_then(|a| a.as_str())
444 .ok_or_else(|| OAuthError::InvalidClient("Missing alg in client_assertion".to_string()))?;
445 if !matches!(
446 alg,
447 "ES256" | "ES384" | "RS256" | "RS384" | "RS512" | "EdDSA"
448 ) {
449 return Err(OAuthError::InvalidClient(format!(
450 "Unsupported client_assertion algorithm: {}",
451 alg
452 )));
453 }
454 let kid = header.get("kid").and_then(|k| k.as_str());
455 let payload_bytes = URL_SAFE_NO_PAD
456 .decode(parts[1])
457 .or_else(|_| STANDARD.decode(parts[1]))
458 .map_err(|e| {
459 tracing::warn!(error = %e, payload_part = parts[1], "Invalid assertion payload encoding");
460 OAuthError::InvalidClient("Invalid assertion payload encoding".to_string())
461 })?;
462 let payload: serde_json::Value = serde_json::from_slice(&payload_bytes)
463 .map_err(|_| OAuthError::InvalidClient("Invalid assertion payload JSON".to_string()))?;
464 let iss = payload
465 .get("iss")
466 .and_then(|i| i.as_str())
467 .ok_or_else(|| OAuthError::InvalidClient("Missing iss in client_assertion".to_string()))?;
468 if iss != metadata.client_id {
469 return Err(OAuthError::InvalidClient(
470 "client_assertion iss does not match client_id".to_string(),
471 ));
472 }
473 let sub = payload
474 .get("sub")
475 .and_then(|s| s.as_str())
476 .ok_or_else(|| OAuthError::InvalidClient("Missing sub in client_assertion".to_string()))?;
477 if sub != metadata.client_id {
478 return Err(OAuthError::InvalidClient(
479 "client_assertion sub does not match client_id".to_string(),
480 ));
481 }
482 let now = chrono::Utc::now().timestamp();
483 let exp = payload.get("exp").and_then(|e| e.as_i64());
484 let iat = payload.get("iat").and_then(|i| i.as_i64());
485 if let Some(exp) = exp {
486 if exp < now {
487 return Err(OAuthError::InvalidClient(
488 "client_assertion has expired".to_string(),
489 ));
490 }
491 } else if let Some(iat) = iat {
492 let max_age_secs = 300;
493 if now - iat > max_age_secs {
494 tracing::warn!(
495 iat = iat,
496 now = now,
497 "client_assertion too old (no exp, using iat)"
498 );
499 return Err(OAuthError::InvalidClient(
500 "client_assertion is too old".to_string(),
501 ));
502 }
503 } else {
504 return Err(OAuthError::InvalidClient(
505 "client_assertion must have exp or iat claim".to_string(),
506 ));
507 }
508 if let Some(iat) = iat
509 && iat > now + 60
510 {
511 return Err(OAuthError::InvalidClient(
512 "client_assertion iat is in the future".to_string(),
513 ));
514 }
515 let jwks = cache.get_jwks(metadata).await?;
516 let keys = jwks
517 .get("keys")
518 .and_then(|k| k.as_array())
519 .ok_or_else(|| OAuthError::InvalidClient("Invalid JWKS: missing keys array".to_string()))?;
520 let matching_keys: Vec<&serde_json::Value> = if let Some(kid) = kid {
521 keys.iter()
522 .filter(|k| k.get("kid").and_then(|v| v.as_str()) == Some(kid))
523 .collect()
524 } else {
525 keys.iter().collect()
526 };
527 if matching_keys.is_empty() {
528 return Err(OAuthError::InvalidClient(
529 "No matching key found in client JWKS".to_string(),
530 ));
531 }
532 let signing_input = format!("{}.{}", parts[0], parts[1]);
533 let signature_bytes = URL_SAFE_NO_PAD
534 .decode(parts[2])
535 .map_err(|_| OAuthError::InvalidClient("Invalid signature encoding".to_string()))?;
536 for key in matching_keys {
537 let key_alg = key.get("alg").and_then(|a| a.as_str());
538 if key_alg.is_some() && key_alg != Some(alg) {
539 continue;
540 }
541 let kty = key.get("kty").and_then(|k| k.as_str()).unwrap_or("");
542 let verified = match (alg, kty) {
543 ("ES256", "EC") => verify_es256(key, &signing_input, &signature_bytes),
544 ("ES384", "EC") => verify_es384(key, &signing_input, &signature_bytes),
545 ("RS256" | "RS384" | "RS512", "RSA") => {
546 verify_rsa(alg, key, &signing_input, &signature_bytes)
547 }
548 ("EdDSA", "OKP") => verify_eddsa(key, &signing_input, &signature_bytes),
549 _ => continue,
550 };
551 if verified.is_ok() {
552 return Ok(());
553 }
554 }
555 Err(OAuthError::InvalidClient(
556 "client_assertion signature verification failed".to_string(),
557 ))
558}
559
560fn verify_es256(
561 key: &serde_json::Value,
562 signing_input: &str,
563 signature: &[u8],
564) -> Result<(), OAuthError> {
565 use base64::{Engine as _, engine::general_purpose::URL_SAFE_NO_PAD};
566 use p256::EncodedPoint;
567 use p256::ecdsa::{Signature, VerifyingKey, signature::Verifier};
568 let x = key
569 .get("x")
570 .and_then(|v| v.as_str())
571 .ok_or_else(|| OAuthError::InvalidClient("Missing x coordinate in EC key".to_string()))?;
572 let y = key
573 .get("y")
574 .and_then(|v| v.as_str())
575 .ok_or_else(|| OAuthError::InvalidClient("Missing y coordinate in EC key".to_string()))?;
576 let x_bytes = URL_SAFE_NO_PAD
577 .decode(x)
578 .map_err(|_| OAuthError::InvalidClient("Invalid x coordinate encoding".to_string()))?;
579 let y_bytes = URL_SAFE_NO_PAD
580 .decode(y)
581 .map_err(|_| OAuthError::InvalidClient("Invalid y coordinate encoding".to_string()))?;
582 let mut point_bytes = vec![0x04];
583 point_bytes.extend_from_slice(&x_bytes);
584 point_bytes.extend_from_slice(&y_bytes);
585 let point = EncodedPoint::from_bytes(&point_bytes)
586 .map_err(|_| OAuthError::InvalidClient("Invalid EC point".to_string()))?;
587 let verifying_key = VerifyingKey::from_encoded_point(&point)
588 .map_err(|_| OAuthError::InvalidClient("Invalid EC key".to_string()))?;
589 let sig = Signature::from_slice(signature)
590 .map_err(|_| OAuthError::InvalidClient("Invalid ES256 signature format".to_string()))?;
591 verifying_key
592 .verify(signing_input.as_bytes(), &sig)
593 .map_err(|_| OAuthError::InvalidClient("ES256 signature verification failed".to_string()))
594}
595
596fn verify_es384(
597 key: &serde_json::Value,
598 signing_input: &str,
599 signature: &[u8],
600) -> Result<(), OAuthError> {
601 use base64::{Engine as _, engine::general_purpose::URL_SAFE_NO_PAD};
602 use p384::EncodedPoint;
603 use p384::ecdsa::{Signature, VerifyingKey, signature::Verifier};
604 let x = key
605 .get("x")
606 .and_then(|v| v.as_str())
607 .ok_or_else(|| OAuthError::InvalidClient("Missing x coordinate in EC key".to_string()))?;
608 let y = key
609 .get("y")
610 .and_then(|v| v.as_str())
611 .ok_or_else(|| OAuthError::InvalidClient("Missing y coordinate in EC key".to_string()))?;
612 let x_bytes = URL_SAFE_NO_PAD
613 .decode(x)
614 .map_err(|_| OAuthError::InvalidClient("Invalid x coordinate encoding".to_string()))?;
615 let y_bytes = URL_SAFE_NO_PAD
616 .decode(y)
617 .map_err(|_| OAuthError::InvalidClient("Invalid y coordinate encoding".to_string()))?;
618 let mut point_bytes = vec![0x04];
619 point_bytes.extend_from_slice(&x_bytes);
620 point_bytes.extend_from_slice(&y_bytes);
621 let point = EncodedPoint::from_bytes(&point_bytes)
622 .map_err(|_| OAuthError::InvalidClient("Invalid EC point".to_string()))?;
623 let verifying_key = VerifyingKey::from_encoded_point(&point)
624 .map_err(|_| OAuthError::InvalidClient("Invalid EC key".to_string()))?;
625 let sig = Signature::from_slice(signature)
626 .map_err(|_| OAuthError::InvalidClient("Invalid ES384 signature format".to_string()))?;
627 verifying_key
628 .verify(signing_input.as_bytes(), &sig)
629 .map_err(|_| OAuthError::InvalidClient("ES384 signature verification failed".to_string()))
630}
631
632fn verify_rsa(
633 _alg: &str,
634 _key: &serde_json::Value,
635 _signing_input: &str,
636 _signature: &[u8],
637) -> Result<(), OAuthError> {
638 Err(OAuthError::InvalidClient(
639 "RSA signature verification not yet supported - use EC keys".to_string(),
640 ))
641}
642
643fn verify_eddsa(
644 key: &serde_json::Value,
645 signing_input: &str,
646 signature: &[u8],
647) -> Result<(), OAuthError> {
648 use base64::{Engine as _, engine::general_purpose::URL_SAFE_NO_PAD};
649 use ed25519_dalek::{Signature, Verifier, VerifyingKey};
650 let crv = key.get("crv").and_then(|c| c.as_str()).unwrap_or("");
651 if crv != "Ed25519" {
652 return Err(OAuthError::InvalidClient(format!(
653 "Unsupported EdDSA curve: {}",
654 crv
655 )));
656 }
657 let x = key
658 .get("x")
659 .and_then(|v| v.as_str())
660 .ok_or_else(|| OAuthError::InvalidClient("Missing x in OKP key".to_string()))?;
661 let x_bytes = URL_SAFE_NO_PAD
662 .decode(x)
663 .map_err(|_| OAuthError::InvalidClient("Invalid x encoding".to_string()))?;
664 let key_bytes: [u8; 32] = x_bytes
665 .try_into()
666 .map_err(|_| OAuthError::InvalidClient("Invalid Ed25519 key length".to_string()))?;
667 let verifying_key = VerifyingKey::from_bytes(&key_bytes)
668 .map_err(|_| OAuthError::InvalidClient("Invalid Ed25519 key".to_string()))?;
669 let sig_bytes: [u8; 64] = signature
670 .try_into()
671 .map_err(|_| OAuthError::InvalidClient("Invalid EdDSA signature length".to_string()))?;
672 let sig = Signature::from_bytes(&sig_bytes);
673 verifying_key
674 .verify(signing_input.as_bytes(), &sig)
675 .map_err(|_| OAuthError::InvalidClient("EdDSA signature verification failed".to_string()))
676}