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lewis.moe
1use base64::Engine;
2use base64::engine::general_purpose::URL_SAFE_NO_PAD;
3use chrono::Utc;
4use hmac::Mac;
5use sha2::{Digest, Sha256};
6use subtle::ConstantTimeEq;
7use crate::config::AuthConfig;
8use crate::oauth::OAuthError;
9const ACCESS_TOKEN_EXPIRY_SECONDS: i64 = 3600;
10pub struct TokenClaims {
11 pub jti: String,
12 pub exp: i64,
13 pub iat: i64,
14}
15pub fn verify_pkce(code_challenge: &str, code_verifier: &str) -> Result<(), OAuthError> {
16 let mut hasher = Sha256::new();
17 hasher.update(code_verifier.as_bytes());
18 let hash = hasher.finalize();
19 let computed_challenge = URL_SAFE_NO_PAD.encode(&hash);
20 if !bool::from(computed_challenge.as_bytes().ct_eq(code_challenge.as_bytes())) {
21 return Err(OAuthError::InvalidGrant("PKCE verification failed".to_string()));
22 }
23 Ok(())
24}
25pub fn create_access_token(
26 token_id: &str,
27 sub: &str,
28 dpop_jkt: Option<&str>,
29) -> Result<String, OAuthError> {
30 use serde_json::json;
31 let pds_hostname = std::env::var("PDS_HOSTNAME").unwrap_or_else(|_| "localhost".to_string());
32 let issuer = format!("https://{}", pds_hostname);
33 let now = Utc::now().timestamp();
34 let exp = now + ACCESS_TOKEN_EXPIRY_SECONDS;
35 let mut payload = json!({
36 "iss": issuer,
37 "sub": sub,
38 "aud": issuer,
39 "iat": now,
40 "exp": exp,
41 "jti": token_id,
42 "scope": "atproto"
43 });
44 if let Some(jkt) = dpop_jkt {
45 payload["cnf"] = json!({ "jkt": jkt });
46 }
47 let header = json!({
48 "alg": "HS256",
49 "typ": "at+jwt"
50 });
51 let header_b64 = URL_SAFE_NO_PAD.encode(serde_json::to_string(&header).unwrap());
52 let payload_b64 = URL_SAFE_NO_PAD.encode(serde_json::to_string(&payload).unwrap());
53 let signing_input = format!("{}.{}", header_b64, payload_b64);
54 let config = AuthConfig::get();
55 type HmacSha256 = hmac::Hmac<Sha256>;
56 let mut mac = HmacSha256::new_from_slice(config.jwt_secret().as_bytes())
57 .map_err(|_| OAuthError::ServerError("HMAC key error".to_string()))?;
58 mac.update(signing_input.as_bytes());
59 let signature = mac.finalize().into_bytes();
60 let signature_b64 = URL_SAFE_NO_PAD.encode(&signature);
61 Ok(format!("{}.{}", signing_input, signature_b64))
62}
63pub fn extract_token_claims(token: &str) -> Result<TokenClaims, OAuthError> {
64 let parts: Vec<&str> = token.split('.').collect();
65 if parts.len() != 3 {
66 return Err(OAuthError::InvalidToken("Invalid token format".to_string()));
67 }
68 let header_bytes = URL_SAFE_NO_PAD
69 .decode(parts[0])
70 .map_err(|_| OAuthError::InvalidToken("Invalid token encoding".to_string()))?;
71 let header: serde_json::Value = serde_json::from_slice(&header_bytes)
72 .map_err(|_| OAuthError::InvalidToken("Invalid token header".to_string()))?;
73 if header.get("typ").and_then(|t| t.as_str()) != Some("at+jwt") {
74 return Err(OAuthError::InvalidToken("Not an OAuth access token".to_string()));
75 }
76 if header.get("alg").and_then(|a| a.as_str()) != Some("HS256") {
77 return Err(OAuthError::InvalidToken("Unsupported algorithm".to_string()));
78 }
79 let config = AuthConfig::get();
80 let secret = config.jwt_secret();
81 let signing_input = format!("{}.{}", parts[0], parts[1]);
82 let provided_sig = URL_SAFE_NO_PAD
83 .decode(parts[2])
84 .map_err(|_| OAuthError::InvalidToken("Invalid signature encoding".to_string()))?;
85 type HmacSha256 = hmac::Hmac<Sha256>;
86 let mut mac = HmacSha256::new_from_slice(secret.as_bytes())
87 .map_err(|_| OAuthError::ServerError("HMAC initialization failed".to_string()))?;
88 mac.update(signing_input.as_bytes());
89 let expected_sig = mac.finalize().into_bytes();
90 if !bool::from(expected_sig.ct_eq(&provided_sig)) {
91 return Err(OAuthError::InvalidToken("Invalid token signature".to_string()));
92 }
93 let payload_bytes = URL_SAFE_NO_PAD
94 .decode(parts[1])
95 .map_err(|_| OAuthError::InvalidToken("Invalid payload encoding".to_string()))?;
96 let payload: serde_json::Value = serde_json::from_slice(&payload_bytes)
97 .map_err(|_| OAuthError::InvalidToken("Invalid token payload".to_string()))?;
98 let jti = payload
99 .get("jti")
100 .and_then(|j| j.as_str())
101 .ok_or_else(|| OAuthError::InvalidToken("Missing jti claim".to_string()))?
102 .to_string();
103 let exp = payload
104 .get("exp")
105 .and_then(|e| e.as_i64())
106 .ok_or_else(|| OAuthError::InvalidToken("Missing exp claim".to_string()))?;
107 let iat = payload
108 .get("iat")
109 .and_then(|i| i.as_i64())
110 .ok_or_else(|| OAuthError::InvalidToken("Missing iat claim".to_string()))?;
111 Ok(TokenClaims { jti, exp, iat })
112}