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
133
134
135
136
137
138

// SPDX-FileCopyrightText: 2021 Heiko Schaefer <heiko@schaefer.name>
// SPDX-License-Identifier: MIT OR Apache-2.0

//! Fingerprint for a single key slot

use std::convert::TryFrom;
use std::convert::TryInto;
use std::fmt;

use nom::{bytes::complete as bytes, combinator, sequence};

use crate::card_do::{Fingerprint, KeySet};
use crate::Error;

impl From<[u8; 20]> for Fingerprint {
    fn from(data: [u8; 20]) -> Self {
        Self(data)
    }
}

impl TryFrom<&[u8]> for Fingerprint {
    type Error = Error;

    fn try_from(input: &[u8]) -> Result<Self, Self::Error> {
        log::trace!("Fingerprint from input: {:x?}, len {}", input, input.len());

        if input.len() == 20 {
            let array: [u8; 20] = input.try_into().unwrap();
            Ok(array.into())
        } else {
            Err(Error::ParseError(format!(
                "Unexpected fingerprint length {}",
                input.len()
            )))
        }
    }
}

impl Fingerprint {
    pub fn as_bytes(&self) -> &[u8] {
        &self.0
    }
}

impl fmt::Display for Fingerprint {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{self:X}")
    }
}

impl fmt::UpperHex for Fingerprint {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        for b in &self.0 {
            write!(f, "{b:02X}")?;
        }
        Ok(())
    }
}

impl fmt::Debug for Fingerprint {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.debug_tuple("Fingerprint")
            .field(&self.to_string())
            .finish()
    }
}

fn fingerprint(input: &[u8]) -> nom::IResult<&[u8], Option<Fingerprint>> {
    combinator::map(bytes::take(20u8), |i: &[u8]| {
        if i.iter().any(|&c| c > 0) {
            // We requested 20 bytes, so we can unwrap here
            let i: [u8; 20] = i.try_into().unwrap();
            Some(i.into())
        } else {
            None
        }
    })(input)
}

fn fingerprints(input: &[u8]) -> nom::IResult<&[u8], KeySet<Fingerprint>> {
    combinator::into(sequence::tuple((fingerprint, fingerprint, fingerprint)))(input)
}

impl TryFrom<&[u8]> for KeySet<Fingerprint> {
    type Error = Error;

    fn try_from(input: &[u8]) -> Result<Self, Self::Error> {
        log::trace!("Fingerprint from input: {:x?}, len {}", input, input.len());

        // The input may be longer than 3 fingerprint, don't fail if it hasn't
        // been completely consumed.
        self::fingerprints(input)
            .map(|res| res.1)
            .map_err(|_err| Error::ParseError("Parsing failed".into()))
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test() {
        let data3 = [
            0xb7, 0xcd, 0x9f, 0x76, 0x37, 0x1e, 0x7, 0x7f, 0x76, 0x1c, 0x82, 0x65, 0x55, 0x54,
            0x3e, 0x6d, 0x65, 0x6d, 0x1d, 0x80, 0x62, 0xd7, 0x34, 0x22, 0x65, 0xd2, 0xef, 0x33,
            0x64, 0xe3, 0x79, 0x52, 0xd9, 0x5e, 0x94, 0x20, 0x5f, 0x4c, 0xce, 0x8b, 0x3f, 0x9,
            0x7a, 0xf2, 0xfd, 0x76, 0xa5, 0xa7, 0x57, 0x9b, 0x51, 0x1f, 0xf, 0x44, 0x9a, 0x25,
            0x80, 0x2d, 0xb2, 0xb8,
        ];

        let fp_set: KeySet<Fingerprint> = (&data3[..])
            .try_into()
            .expect("failed to parse fingerprint set");

        assert_eq!(
            format!("{}", fp_set.signature().unwrap()),
            "B7CD9F76371E077F761C826555543E6D656D1D80"
        );
        assert_eq!(
            format!("{}", fp_set.decryption().unwrap()),
            "62D7342265D2EF3364E37952D95E94205F4CCE8B"
        );
        assert_eq!(
            format!("{}", fp_set.authentication().unwrap()),
            "3F097AF2FD76A5A7579B511F0F449A25802DB2B8"
        );

        let data1 = [
            0xb7, 0xcd, 0x9f, 0x76, 0x37, 0x1e, 0x7, 0x7f, 0x76, 0x1c, 0x82, 0x65, 0x55, 0x54,
            0x3e, 0x6d, 0x65, 0x6d, 0x1d, 0x80,
        ];

        let fp = Fingerprint::try_from(&data1[..]).expect("failed to parse fingerprint");

        assert_eq!(format!("{fp}"), "B7CD9F76371E077F761C826555543E6D656D1D80");
    }
}