mz_auth/
hash.rs

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1// Copyright Materialize, Inc. and contributors. All rights reserved.
2//
3// Use of this software is governed by the Business Source License
4// included in the LICENSE file.
5//
6// As of the Change Date specified in that file, in accordance with
7// the Business Source License, use of this software will be governed
8// by the Apache License, Version 2.0.
9
10// Clippy misreads some doc comments as HTML tags, so we disable the lint
11#![allow(rustdoc::invalid_html_tags)]
12
13use std::fmt::Display;
14use std::num::NonZeroU32;
15
16use base64::prelude::*;
17
18use crate::password::Password;
19
20/// The default iteration count as suggested by
21/// <https://cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html>
22const DEFAULT_ITERATIONS: NonZeroU32 = NonZeroU32::new(600_000).unwrap();
23
24/// The default salt size, which isn't currently configurable.
25const DEFAULT_SALT_SIZE: usize = 32;
26
27const SHA256_OUTPUT_LEN: usize = 32;
28
29/// The options for hashing a password
30pub struct HashOpts {
31    /// The number of iterations to use for PBKDF2
32    pub iterations: NonZeroU32,
33    /// The salt to use for PBKDF2. It is up to the caller to
34    /// ensure that however the salt is generated, it is cryptographically
35    /// secure.
36    pub salt: [u8; DEFAULT_SALT_SIZE],
37}
38
39pub struct PasswordHash {
40    /// The salt used for hashing
41    pub salt: [u8; DEFAULT_SALT_SIZE],
42    /// The number of iterations used for hashing
43    pub iterations: NonZeroU32,
44    /// The hash of the password.
45    /// This is the result of PBKDF2 with SHA256
46    pub hash: [u8; SHA256_OUTPUT_LEN],
47}
48
49#[derive(Debug)]
50pub enum VerifyError {
51    MalformedHash,
52    InvalidPassword,
53    Hash(HashError),
54}
55
56#[derive(Debug)]
57pub enum HashError {
58    Openssl(openssl::error::ErrorStack),
59}
60
61/// Hashes a password using PBKDF2 with SHA256
62/// and a random salt.
63pub fn hash_password(password: &Password) -> Result<PasswordHash, HashError> {
64    let mut salt = [0u8; DEFAULT_SALT_SIZE];
65    openssl::rand::rand_bytes(&mut salt).map_err(HashError::Openssl)?;
66
67    let hash = hash_password_inner(
68        &HashOpts {
69            iterations: DEFAULT_ITERATIONS,
70            salt,
71        },
72        password.to_string().as_bytes(),
73    )?;
74
75    Ok(PasswordHash {
76        salt,
77        iterations: DEFAULT_ITERATIONS,
78        hash,
79    })
80}
81
82/// Hashes a password using PBKDF2 with SHA256
83/// and the given options.
84pub fn hash_password_with_opts(
85    opts: &HashOpts,
86    password: &Password,
87) -> Result<PasswordHash, HashError> {
88    let hash = hash_password_inner(opts, password.to_string().as_bytes())?;
89
90    Ok(PasswordHash {
91        salt: opts.salt,
92        iterations: opts.iterations,
93        hash,
94    })
95}
96
97/// Hashes a password using PBKDF2 with SHA256,
98/// and returns it in the SCRAM-SHA-256 format.
99/// The format is SCRAM-SHA-256$<iterations>:<salt>$<client_key>:<server_key>
100pub fn scram256_hash(password: &Password) -> Result<String, HashError> {
101    let hashed_password = hash_password(password)?;
102    Ok(scram256_hash_inner(hashed_password).to_string())
103}
104
105/// Verifies a password against a SCRAM-SHA-256 hash.
106pub fn scram256_verify(password: &Password, hashed_password: &str) -> Result<(), VerifyError> {
107    let opts = scram256_parse_opts(hashed_password)?;
108    let hashed = hash_password_with_opts(&opts, password).map_err(VerifyError::Hash)?;
109    let scram = scram256_hash_inner(hashed);
110    if *hashed_password == scram.to_string() {
111        Ok(())
112    } else {
113        Err(VerifyError::InvalidPassword)
114    }
115}
116
117/// Parses a SCRAM-SHA-256 hash and returns the options used to create it.
118fn scram256_parse_opts(hashed_password: &str) -> Result<HashOpts, VerifyError> {
119    let parts: Vec<&str> = hashed_password.split('$').collect();
120    if parts.len() != 3 {
121        return Err(VerifyError::MalformedHash);
122    }
123    let scheme = parts[0];
124    if scheme != "SCRAM-SHA-256" {
125        return Err(VerifyError::MalformedHash);
126    }
127    let auth_info = parts[1].split(':').collect::<Vec<&str>>();
128    if auth_info.len() != 2 {
129        return Err(VerifyError::MalformedHash);
130    }
131    let auth_value = parts[2].split(':').collect::<Vec<&str>>();
132    if auth_value.len() != 2 {
133        return Err(VerifyError::MalformedHash);
134    }
135
136    let iterations = auth_info[0]
137        .parse::<u32>()
138        .map_err(|_| VerifyError::MalformedHash)?;
139
140    let salt = BASE64_STANDARD
141        .decode(auth_info[1])
142        .map_err(|_| VerifyError::MalformedHash)?;
143
144    let salt = salt.try_into().map_err(|_| VerifyError::MalformedHash)?;
145
146    Ok(HashOpts {
147        iterations: NonZeroU32::new(iterations).ok_or(VerifyError::MalformedHash)?,
148        salt,
149    })
150}
151
152/// The SCRAM-SHA-256 hash
153struct ScramSha256Hash {
154    /// The number of iterations used for hashing
155    iterations: NonZeroU32,
156    /// The salt used for hashing
157    salt: [u8; 32],
158    /// The server key
159    server_key: [u8; SHA256_OUTPUT_LEN],
160    /// The client key
161    client_key: [u8; SHA256_OUTPUT_LEN],
162}
163
164impl Display for ScramSha256Hash {
165    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
166        write!(
167            f,
168            "SCRAM-SHA-256${}:{}${}:{}",
169            self.iterations,
170            BASE64_STANDARD.encode(&self.salt),
171            BASE64_STANDARD.encode(&self.client_key),
172            BASE64_STANDARD.encode(&self.server_key)
173        )
174    }
175}
176
177fn scram256_hash_inner(hashed_password: PasswordHash) -> ScramSha256Hash {
178    let signing_key = openssl::pkey::PKey::hmac(&hashed_password.hash).unwrap();
179    let mut signer =
180        openssl::sign::Signer::new(openssl::hash::MessageDigest::sha256(), &signing_key).unwrap();
181    signer.update(b"Client Key").unwrap();
182    let client_key = signer.sign_to_vec().unwrap();
183    let mut signer =
184        openssl::sign::Signer::new(openssl::hash::MessageDigest::sha256(), &signing_key).unwrap();
185    signer.update(b"Server Key").unwrap();
186    let server_key = signer.sign_to_vec().unwrap();
187
188    ScramSha256Hash {
189        iterations: hashed_password.iterations,
190        salt: hashed_password.salt,
191        server_key: server_key.try_into().unwrap(),
192        client_key: client_key.try_into().unwrap(),
193    }
194}
195
196fn hash_password_inner(
197    opts: &HashOpts,
198    password: &[u8],
199) -> Result<[u8; SHA256_OUTPUT_LEN], HashError> {
200    let mut salted_password = [0u8; SHA256_OUTPUT_LEN];
201    openssl::pkcs5::pbkdf2_hmac(
202        password,
203        &opts.salt,
204        opts.iterations.get().try_into().unwrap(),
205        openssl::hash::MessageDigest::sha256(),
206        &mut salted_password,
207    )
208    .map_err(HashError::Openssl)?;
209    Ok(salted_password)
210}
211
212#[cfg(test)]
213mod tests {
214    use super::*;
215
216    #[mz_ore::test]
217    #[cfg_attr(miri, ignore)] // unsupported operation: can't call foreign function `OPENSSL_init_ssl` on OS `linux`
218    fn test_hash_password() {
219        let password = "password".to_string();
220        let hashed_password = hash_password(&password.into()).expect("Failed to hash password");
221        assert_eq!(hashed_password.iterations, DEFAULT_ITERATIONS);
222        assert_eq!(hashed_password.salt.len(), DEFAULT_SALT_SIZE);
223        assert_eq!(hashed_password.hash.len(), SHA256_OUTPUT_LEN);
224    }
225
226    #[mz_ore::test]
227    #[cfg_attr(miri, ignore)] // unsupported operation: can't call foreign function `OPENSSL_init_ssl` on OS `linux`
228    fn test_scram256_hash() {
229        let password = "password".into();
230        let scram_hash = scram256_hash(&password).expect("Failed to hash password");
231
232        let res = scram256_verify(&password, &scram_hash);
233        assert!(res.is_ok());
234        let res = scram256_verify(&"wrong_password".into(), &scram_hash);
235        assert!(res.is_err());
236    }
237
238    #[mz_ore::test]
239    fn test_scram256_parse_opts() {
240        let salt = "9bkIQQjQ7f1OwPsXZGC/YfIkbZsOMDXK0cxxvPBaSfM=";
241        let hashed_password = format!("SCRAM-SHA-256$600000:{}$client-key:server-key", salt);
242        let opts = scram256_parse_opts(&hashed_password);
243
244        assert!(opts.is_ok());
245        let opts = opts.unwrap();
246        assert_eq!(opts.iterations, DEFAULT_ITERATIONS);
247        assert_eq!(opts.salt.len(), DEFAULT_SALT_SIZE);
248        let decoded_salt = BASE64_STANDARD.decode(salt).expect("Failed to decode salt");
249        assert_eq!(opts.salt, decoded_salt.as_ref());
250    }
251}
mz_auth/hash.rs

mz_auth/
hash.rs
