kellnr_db/
password.rs

1use argon2::{Algorithm, Argon2, Params, Version};
2use password_hash::rand_core::OsRng;
3use password_hash::{PasswordHash, PasswordHasher, PasswordVerifier, SaltString};
4use subtle::ConstantTimeEq;
5
6/// Outcome of checking a password against its stored hash.
7#[derive(Debug, Clone, Copy, PartialEq, Eq)]
8pub enum PwdVerification {
9    Valid,
10    /// The password matches a legacy SHA-256 hash and should be rehashed.
11    ValidLegacy,
12    Invalid,
13}
14
15fn argon2() -> Argon2<'static> {
16    // argon2id with the OWASP recommended minimum (19 MiB, 2 iterations).
17    Argon2::new(Algorithm::Argon2id, Version::V0x13, Params::default())
18}
19
20/// Hashes a password with argon2id and returns it in PHC string format. The
21/// random salt is part of the returned string.
22///
23/// Hashing is CPU heavy by design, so it runs on the blocking thread pool to
24/// keep the async workers responsive.
25pub async fn hash_pwd(pwd: &str) -> String {
26    let pwd = pwd.to_owned();
27    run_blocking(move || hash_pwd_sync(&pwd)).await
28}
29
30/// Verifies `pwd` against `stored_hash`. Hashes in PHC format are checked with
31/// argon2. Anything else is treated as a legacy `sha256(pwd + salt)` hash
32/// created by older Kellnr versions, which uses the separately stored salt.
33pub async fn verify_pwd(pwd: &str, stored_hash: &str, legacy_salt: &str) -> PwdVerification {
34    let (pwd, stored_hash, legacy_salt) = (
35        pwd.to_owned(),
36        stored_hash.to_owned(),
37        legacy_salt.to_owned(),
38    );
39    run_blocking(move || verify_pwd_sync(&pwd, &stored_hash, &legacy_salt)).await
40}
41
42async fn run_blocking<T: Send + 'static>(f: impl FnOnce() -> T + Send + 'static) -> T {
43    tokio::task::spawn_blocking(f)
44        .await
45        .expect("password hashing task panicked")
46}
47
48fn hash_pwd_sync(pwd: &str) -> String {
49    let salt = SaltString::generate(&mut OsRng);
50    argon2()
51        .hash_password(pwd.as_bytes(), &salt)
52        .expect("argon2 hashing with default parameters cannot fail")
53        .to_string()
54}
55
56fn verify_pwd_sync(pwd: &str, stored_hash: &str, legacy_salt: &str) -> PwdVerification {
57    if stored_hash.starts_with('$') {
58        return match PasswordHash::new(stored_hash) {
59            Ok(parsed) if argon2().verify_password(pwd.as_bytes(), &parsed).is_ok() => {
60                PwdVerification::Valid
61            }
62            _ => PwdVerification::Invalid,
63        };
64    }
65
66    let legacy = legacy_hash(pwd, legacy_salt);
67    if bool::from(legacy.as_bytes().ct_eq(stored_hash.as_bytes())) {
68        PwdVerification::ValidLegacy
69    } else {
70        PwdVerification::Invalid
71    }
72}
73
74pub(crate) fn legacy_hash(pwd: &str, salt: &str) -> String {
75    sha256::digest(format!("{pwd}{salt}"))
76}
77
78pub fn hash_token(token: &str) -> String {
79    sha256::digest(token)
80}
81
82#[cfg(test)]
83mod tests {
84    use super::*;
85
86    #[test]
87    fn hash_pwd_produces_argon2id_phc_string() {
88        let hash = hash_pwd_sync("admin");
89
90        assert!(
91            hash.starts_with("$argon2id$v=19$"),
92            "unexpected hash {hash}"
93        );
94    }
95
96    #[test]
97    fn hash_pwd_uses_random_salt() {
98        assert_ne!(hash_pwd_sync("admin"), hash_pwd_sync("admin"));
99    }
100
101    #[test]
102    fn verify_pwd_accepts_argon2_hash() {
103        let hash = hash_pwd_sync("admin");
104
105        assert_eq!(verify_pwd_sync("admin", &hash, ""), PwdVerification::Valid);
106        assert_eq!(
107            verify_pwd_sync("wrong", &hash, ""),
108            PwdVerification::Invalid
109        );
110    }
111
112    #[test]
113    fn verify_pwd_accepts_legacy_hash() {
114        let salt = "C6udtgbngX";
115        let legacy = "5dcec54caf0f55652766f71c32a0eac6538e7faeeab9301f956a58b7dbad02fb";
116
117        assert_eq!(
118            verify_pwd_sync("admin", legacy, salt),
119            PwdVerification::ValidLegacy
120        );
121        assert_eq!(
122            verify_pwd_sync("wrong", legacy, salt),
123            PwdVerification::Invalid
124        );
125        assert_eq!(
126            verify_pwd_sync("admin", legacy, "other_salt"),
127            PwdVerification::Invalid
128        );
129    }
130
131    #[test]
132    fn verify_pwd_rejects_malformed_phc_string() {
133        assert_eq!(
134            verify_pwd_sync("admin", "$argon2id$garbage", ""),
135            PwdVerification::Invalid
136        );
137    }
138
139    #[test]
140    fn verify_pwd_rejects_empty_hash() {
141        assert_eq!(verify_pwd_sync("", "", ""), PwdVerification::Invalid);
142    }
143
144    #[test]
145    fn legacy_hash_computes_sha256_of_pwd_and_salt() {
146        assert_eq!(
147            legacy_hash("admin", "C6udtgbngX"),
148            "5dcec54caf0f55652766f71c32a0eac6538e7faeeab9301f956a58b7dbad02fb"
149        );
150    }
151}
kellnr_db/password.rs

kellnr_db/
password.rs
