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