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lewis.moe
1use crate::config::AuthConfig;
2use crate::oauth::OAuthError;
3use base64::Engine;
4use base64::engine::general_purpose::URL_SAFE_NO_PAD;
5use chrono::Utc;
6use hmac::Mac;
7use sha2::{Digest, Sha256};
8use subtle::ConstantTimeEq;
9
10const ACCESS_TOKEN_EXPIRY_SECONDS: i64 = 300;
11
12pub struct TokenClaims {
13 pub jti: String,
14 pub exp: i64,
15 pub iat: i64,
16}
17
18pub fn verify_pkce(code_challenge: &str, code_verifier: &str) -> Result<(), OAuthError> {
19 let mut hasher = Sha256::new();
20 hasher.update(code_verifier.as_bytes());
21 let hash = hasher.finalize();
22 let computed_challenge = URL_SAFE_NO_PAD.encode(hash);
23 if !bool::from(
24 computed_challenge
25 .as_bytes()
26 .ct_eq(code_challenge.as_bytes()),
27 ) {
28 return Err(OAuthError::InvalidGrant(
29 "PKCE verification failed".to_string(),
30 ));
31 }
32 Ok(())
33}
34
35pub fn create_access_token(
36 token_id: &str,
37 sub: &str,
38 dpop_jkt: Option<&str>,
39 scope: Option<&str>,
40) -> Result<String, OAuthError> {
41 create_access_token_with_delegation(token_id, sub, dpop_jkt, scope, None)
42}
43
44pub fn create_access_token_with_delegation(
45 token_id: &str,
46 sub: &str,
47 dpop_jkt: Option<&str>,
48 scope: Option<&str>,
49 controller_did: Option<&str>,
50) -> Result<String, OAuthError> {
51 use serde_json::json;
52 let pds_hostname = std::env::var("PDS_HOSTNAME").unwrap_or_else(|_| "localhost".to_string());
53 let issuer = format!("https://{}", pds_hostname);
54 let now = Utc::now().timestamp();
55 let exp = now + ACCESS_TOKEN_EXPIRY_SECONDS;
56 let actual_scope = scope.unwrap_or("atproto");
57 let mut payload = json!({
58 "iss": issuer,
59 "sub": sub,
60 "aud": issuer,
61 "iat": now,
62 "exp": exp,
63 "jti": token_id,
64 "scope": actual_scope
65 });
66 if let Some(jkt) = dpop_jkt {
67 payload["cnf"] = json!({ "jkt": jkt });
68 }
69 if let Some(controller) = controller_did {
70 payload["act"] = json!({ "sub": controller });
71 }
72 let header = json!({
73 "alg": "HS256",
74 "typ": "at+jwt"
75 });
76 let header_b64 = URL_SAFE_NO_PAD.encode(serde_json::to_string(&header).unwrap());
77 let payload_b64 = URL_SAFE_NO_PAD.encode(serde_json::to_string(&payload).unwrap());
78 let signing_input = format!("{}.{}", header_b64, payload_b64);
79 let config = AuthConfig::get();
80 type HmacSha256 = hmac::Hmac<Sha256>;
81 let mut mac = HmacSha256::new_from_slice(config.jwt_secret().as_bytes())
82 .map_err(|_| OAuthError::ServerError("HMAC key error".to_string()))?;
83 mac.update(signing_input.as_bytes());
84 let signature = mac.finalize().into_bytes();
85 let signature_b64 = URL_SAFE_NO_PAD.encode(signature);
86 Ok(format!("{}.{}", signing_input, signature_b64))
87}
88
89pub fn extract_token_claims(token: &str) -> Result<TokenClaims, OAuthError> {
90 let parts: Vec<&str> = token.split('.').collect();
91 if parts.len() != 3 {
92 return Err(OAuthError::InvalidToken("Invalid token format".to_string()));
93 }
94 let header_bytes = URL_SAFE_NO_PAD
95 .decode(parts[0])
96 .map_err(|_| OAuthError::InvalidToken("Invalid token encoding".to_string()))?;
97 let header: serde_json::Value = serde_json::from_slice(&header_bytes)
98 .map_err(|_| OAuthError::InvalidToken("Invalid token header".to_string()))?;
99 if header.get("typ").and_then(|t| t.as_str()) != Some("at+jwt") {
100 return Err(OAuthError::InvalidToken(
101 "Not an OAuth access token".to_string(),
102 ));
103 }
104 if header.get("alg").and_then(|a| a.as_str()) != Some("HS256") {
105 return Err(OAuthError::InvalidToken(
106 "Unsupported algorithm".to_string(),
107 ));
108 }
109 let config = AuthConfig::get();
110 let secret = config.jwt_secret();
111 let signing_input = format!("{}.{}", parts[0], parts[1]);
112 let provided_sig = URL_SAFE_NO_PAD
113 .decode(parts[2])
114 .map_err(|_| OAuthError::InvalidToken("Invalid signature encoding".to_string()))?;
115 type HmacSha256 = hmac::Hmac<Sha256>;
116 let mut mac = HmacSha256::new_from_slice(secret.as_bytes())
117 .map_err(|_| OAuthError::ServerError("HMAC initialization failed".to_string()))?;
118 mac.update(signing_input.as_bytes());
119 let expected_sig = mac.finalize().into_bytes();
120 if !bool::from(expected_sig.ct_eq(&provided_sig)) {
121 return Err(OAuthError::InvalidToken(
122 "Invalid token signature".to_string(),
123 ));
124 }
125 let payload_bytes = URL_SAFE_NO_PAD
126 .decode(parts[1])
127 .map_err(|_| OAuthError::InvalidToken("Invalid payload encoding".to_string()))?;
128 let payload: serde_json::Value = serde_json::from_slice(&payload_bytes)
129 .map_err(|_| OAuthError::InvalidToken("Invalid token payload".to_string()))?;
130 let jti = payload
131 .get("jti")
132 .and_then(|j| j.as_str())
133 .ok_or_else(|| OAuthError::InvalidToken("Missing jti claim".to_string()))?
134 .to_string();
135 let exp = payload
136 .get("exp")
137 .and_then(|e| e.as_i64())
138 .ok_or_else(|| OAuthError::InvalidToken("Missing exp claim".to_string()))?;
139 let iat = payload
140 .get("iat")
141 .and_then(|i| i.as_i64())
142 .ok_or_else(|| OAuthError::InvalidToken("Missing iat claim".to_string()))?;
143 Ok(TokenClaims { jti, exp, iat })
144}