bitwarden_crypto/
util.rs

1use std::pin::Pin;
2
3use ::aes::cipher::{ArrayLength, Unsigned};
4use generic_array::GenericArray;
5use hmac::digest::OutputSizeUser;
6use rand::{
7    distributions::{Alphanumeric, DistString, Distribution, Standard},
8    Rng,
9};
10use zeroize::{Zeroize, Zeroizing};
11
12use crate::{CryptoError, Result};
13
14pub(crate) type PbkdfSha256Hmac = hmac::Hmac<sha2::Sha256>;
15pub(crate) const PBKDF_SHA256_HMAC_OUT_SIZE: usize =
16    <<PbkdfSha256Hmac as OutputSizeUser>::OutputSize as Unsigned>::USIZE;
17
18/// [RFC5869](https://datatracker.ietf.org/doc/html/rfc5869) HKDF-Expand operation
19pub(crate) fn hkdf_expand<T: ArrayLength<u8>>(
20    prk: &[u8],
21    info: Option<&str>,
22) -> Result<Pin<Box<GenericArray<u8, T>>>> {
23    let hkdf = hkdf::Hkdf::<sha2::Sha256>::from_prk(prk).map_err(|_| CryptoError::InvalidKeyLen)?;
24    let mut key = Box::<GenericArray<u8, T>>::default();
25
26    let i = info.map(|i| i.as_bytes()).unwrap_or(&[]);
27    hkdf.expand(i, &mut key)
28        .map_err(|_| CryptoError::InvalidKeyLen)?;
29
30    Ok(Box::into_pin(key))
31}
32
33/// Generate random bytes that are cryptographically secure
34pub fn generate_random_bytes<T>() -> Zeroizing<T>
35where
36    Standard: Distribution<T>,
37    T: Zeroize,
38{
39    Zeroizing::new(rand::thread_rng().r#gen::<T>())
40}
41
42/// Generate a random alphanumeric string of a given length
43///
44/// Note: Do not use this generating user facing passwords. Use the `bitwarden-generator` crate for
45/// that.
46pub fn generate_random_alphanumeric(len: usize) -> String {
47    Alphanumeric.sample_string(&mut rand::thread_rng(), len)
48}
49
50/// Derive pbkdf2 of a given password and salt
51pub fn pbkdf2(password: &[u8], salt: &[u8], rounds: u32) -> [u8; PBKDF_SHA256_HMAC_OUT_SIZE] {
52    pbkdf2::pbkdf2_array::<PbkdfSha256Hmac, PBKDF_SHA256_HMAC_OUT_SIZE>(password, salt, rounds)
53        .expect("hash is a valid fixed size")
54}
55
56#[cfg(test)]
57mod tests {
58    use typenum::U64;
59
60    use super::*;
61
62    #[test]
63    fn test_hkdf_expand() {
64        let prk = &[
65            23, 152, 120, 41, 214, 16, 156, 133, 71, 226, 178, 135, 208, 255, 66, 101, 189, 70,
66            173, 30, 39, 215, 175, 236, 38, 180, 180, 62, 196, 4, 159, 70,
67        ];
68        let info = Some("info");
69
70        let result: Pin<Box<GenericArray<u8, U64>>> = hkdf_expand(prk, info).unwrap();
71
72        let expected_output: [u8; 64] = [
73            6, 114, 42, 38, 87, 231, 30, 109, 30, 255, 104, 129, 255, 94, 92, 108, 124, 145, 215,
74            208, 17, 60, 135, 22, 70, 158, 40, 53, 45, 182, 8, 63, 65, 87, 239, 234, 185, 227, 153,
75            122, 115, 205, 144, 56, 102, 149, 92, 139, 217, 102, 119, 57, 37, 57, 251, 178, 18, 52,
76            94, 77, 132, 215, 239, 100,
77        ];
78
79        assert_eq!(result.as_slice(), expected_output);
80    }
81}
bitwarden_crypto/util.rs

bitwarden_crypto/
util.rs
