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alibi_plugins/email_otp/
storage.rs

1use crate::token_crypto::{decrypt_with_config, encrypt_with_config, hash_token};
2use alibi_core::{AuthError, AuthResult};
3use async_trait::async_trait;
4use std::sync::Arc;
5
6/// Application-owned codec for custom hash/encryption storage.
7/// `retrieve` returns `None` when the representation is intentionally irreversible.
8#[async_trait]
9pub trait EmailOtpCodec: Send + Sync {
10    async fn store(&self, otp: &str) -> AuthResult<String>;
11    async fn verify(&self, stored: &str, otp: &str) -> AuthResult<bool>;
12    async fn retrieve(&self, stored: &str) -> AuthResult<Option<String>>;
13}
14
15#[derive(Clone)]
16pub enum EmailOtpStorage {
17    Plain,
18    Hashed,
19    Encrypted,
20    Custom(Arc<dyn EmailOtpCodec>),
21}
22
23impl std::fmt::Debug for EmailOtpStorage {
24    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
25        match self {
26            Self::Plain => f.write_str("EmailOtpStorage::Plain"),
27            Self::Hashed => f.write_str("EmailOtpStorage::Hashed"),
28            Self::Encrypted => f.write_str("EmailOtpStorage::Encrypted"),
29            Self::Custom(..) => f.write_str("EmailOtpStorage::Custom"),
30        }
31    }
32}
33
34impl EmailOtpStorage {
35    pub(super) async fn store(
36        &self,
37        otp: &str,
38        secret: &alibi_core::AuthConfig,
39    ) -> AuthResult<String> {
40        match self {
41            Self::Plain => Ok(otp.to_owned()),
42            Self::Hashed => Ok(hash_token(otp)),
43            Self::Encrypted => encrypt_with_config(otp, secret),
44            Self::Custom(codec) => codec.store(otp).await,
45        }
46    }
47
48    pub(super) async fn verify(
49        &self,
50        stored: &str,
51        otp: &str,
52        secret: &alibi_core::AuthConfig,
53    ) -> AuthResult<bool> {
54        match self {
55            Self::Plain => Ok(constant_time_equal(stored, otp)),
56            Self::Hashed => Ok(constant_time_equal(stored, &hash_token(otp))),
57            Self::Encrypted => Ok(constant_time_equal(
58                &decrypt_with_config(stored, secret)?,
59                otp,
60            )),
61            Self::Custom(codec) => codec.verify(stored, otp).await,
62        }
63    }
64
65    pub(super) async fn retrieve(
66        &self,
67        stored: &str,
68        secret: &alibi_core::AuthConfig,
69    ) -> AuthResult<Option<String>> {
70        let plain = match self {
71            Self::Plain => Some(stored.to_owned()),
72            Self::Hashed => None,
73            Self::Encrypted => Some(decrypt_with_config(stored, secret)?),
74            Self::Custom(codec) => codec.retrieve(stored).await?,
75        };
76        plain.map(Some).ok_or_else(|| {
77            AuthError::bad_request("OTP is hashed, cannot return the plain text OTP")
78        })
79    }
80
81    pub(super) async fn reusable(
82        &self,
83        stored: &str,
84        secret: &alibi_core::AuthConfig,
85    ) -> AuthResult<Option<String>> {
86        match self {
87            Self::Hashed => Ok(None),
88            Self::Custom(codec) => codec.retrieve(stored).await,
89            Self::Plain | Self::Encrypted => self.retrieve(stored, secret).await,
90        }
91    }
92}
93
94fn constant_time_equal(left: &str, right: &str) -> bool {
95    if left.len() != right.len() {
96        return false;
97    }
98    left.bytes()
99        .zip(right.bytes())
100        .fold(0u8, |difference, (a, b)| difference | (a ^ b))
101        == 0
102}