1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132

use std::fmt::Write;

use md5::{Digest, Md5};

use crate::io::PgBufMutExt;
use crate::io::{BufMutExt, Encode};

#[derive(Debug)]
pub enum Password<'a> {
    Cleartext(&'a str),

    Md5 {
        password: &'a str,
        username: &'a str,
        salt: [u8; 4],
    },
}

impl Password<'_> {
    #[inline]
    fn len(&self) -> usize {
        match self {
            Password::Cleartext(s) => s.len() + 5,
            Password::Md5 { .. } => 35 + 5,
        }
    }
}

impl Encode<'_> for Password<'_> {
    fn encode_with(&self, buf: &mut Vec<u8>, _: ()) {
        buf.reserve(1 + 4 + self.len());
        buf.push(b'p');

        buf.put_length_prefixed(|buf| {
            match self {
                Password::Cleartext(password) => {
                    buf.put_str_nul(password);
                }

                Password::Md5 {
                    username,
                    password,
                    salt,
                } => {
                    // The actual `PasswordMessage` can be computed in SQL as
                    // `concat('md5', md5(concat(md5(concat(password, username)), random-salt)))`.

                    // Keep in mind the md5() function returns its result as a hex string.

                    let mut hasher = Md5::new();

                    hasher.update(password);
                    hasher.update(username);

                    let mut output = String::with_capacity(35);

                    let _ = write!(output, "{:x}", hasher.finalize_reset());

                    hasher.update(&output);
                    hasher.update(salt);

                    output.clear();

                    let _ = write!(output, "md5{:x}", hasher.finalize());

                    buf.put_str_nul(&output);
                }
            }
        });
    }
}

#[test]
fn test_encode_clear_password() {
    const EXPECTED: &[u8] = b"p\0\0\0\rpassword\0";

    let mut buf = Vec::new();
    let m = Password::Cleartext("password");

    m.encode(&mut buf);

    assert_eq!(buf, EXPECTED);
}

#[test]
fn test_encode_md5_password() {
    const EXPECTED: &[u8] = b"p\0\0\0(md53e2c9d99d49b201ef867a36f3f9ed62c\0";

    let mut buf = Vec::new();
    let m = Password::Md5 {
        password: "password",
        username: "root",
        salt: [147, 24, 57, 152],
    };

    m.encode(&mut buf);

    assert_eq!(buf, EXPECTED);
}

#[cfg(all(test, not(debug_assertions)))]
#[bench]
fn bench_encode_clear_password(b: &mut test::Bencher) {
    use test::black_box;

    let mut buf = Vec::with_capacity(128);

    b.iter(|| {
        buf.clear();

        black_box(Password::Cleartext("password")).encode(&mut buf);
    });
}

#[cfg(all(test, not(debug_assertions)))]
#[bench]
fn bench_encode_md5_password(b: &mut test::Bencher) {
    use test::black_box;

    let mut buf = Vec::with_capacity(128);

    b.iter(|| {
        buf.clear();

        black_box(Password::Md5 {
            password: "password",
            username: "root",
            salt: [147, 24, 57, 152],
        })
        .encode(&mut buf);
    });
}