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
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157

use std;
use hmacmode::{ HmacKey };
use otpmode::{ Aes128Key };
use sec::{ crc16 };
use manager::Frame;
use config::Command;

const FIXED_SIZE: usize = 16;
const UID_SIZE: usize = 6;
const KEY_SIZE: usize = 16;
const ACC_CODE_SIZE: usize = 6;

/// The configuration of a YubiKey.
#[repr(C)]
#[repr(packed)]
pub struct DeviceModeConfig {
    pub fixed: [u8; FIXED_SIZE],
    pub uid: [u8; UID_SIZE],
    pub key: [u8; KEY_SIZE],
    pub acc_code: [u8; ACC_CODE_SIZE],
    pub fixed_size: u8,
    pub ext_flags: ExtendedFlags,
    pub tkt_flags: TicketFlags,
    pub cfg_flags: ConfigFlags,
    pub rfu: [u8; 2],
    pub crc: u16,
}

impl std::default::Default for DeviceModeConfig {
    fn default() -> Self {
        DeviceModeConfig {
            fixed: [0; FIXED_SIZE],
            uid: [0; UID_SIZE],
            key: [0; KEY_SIZE],
            acc_code: [0; ACC_CODE_SIZE],
            fixed_size: 0,
            ext_flags: ExtendedFlags::empty(),
            tkt_flags: TicketFlags::empty(),
            cfg_flags: ConfigFlags::empty(),
            rfu: [0; 2],
            crc: 0,
        }
    }
}

const SIZEOF_CONFIG: usize = 52;

impl DeviceModeConfig {

    #[doc(hidden)]
    pub fn to_frame(&mut self, command: Command) -> Frame {
        let mut payload = [0; 64];
        // First set CRC.
        self.crc = {
            let first_fields = unsafe {
                std::slice::from_raw_parts(self as *const DeviceModeConfig as *const u8, SIZEOF_CONFIG - 2)
            };
            (0xffff - crc16(&first_fields)).to_le()
        };

        // Then write to the payload.
        let s = unsafe {
            std::slice::from_raw_parts(self as *const DeviceModeConfig as *const u8, SIZEOF_CONFIG)
        };
        (&mut payload[..SIZEOF_CONFIG]).clone_from_slice(s);

        Frame::new(payload, command)
    }

    /// Sets the configuration in challenge-response, HMAC-SHA1
    /// mode. This mode has two sub-modes: if `variable` is `true`,
    /// the challenges can be of variable length up to 63 bytes. Else,
    /// all challenges must be exactly 64 bytes long.
    pub fn challenge_response_hmac(&mut self, secret: &HmacKey, variable: bool, button:bool) {
        self.tkt_flags = TicketFlags::empty();
        self.cfg_flags = ConfigFlags::empty();
        self.ext_flags = ExtendedFlags::empty();

        self.tkt_flags.insert(TicketFlags::CHAL_RESP);
        self.cfg_flags.insert(if button { ConfigFlags::CHAL_HMAC | ConfigFlags::CHAL_BTN_TRIG } else { ConfigFlags::CHAL_HMAC });
        if variable {
            self.cfg_flags.insert(ConfigFlags::HMAC_LT64)
        } else {
            self.cfg_flags.remove(ConfigFlags::HMAC_LT64)
        }
        let (a, b) = secret.0.split_at(16);
        self.key.copy_from_slice(a);
        (&mut self.uid[..4]).copy_from_slice(b);
    }

    /// Sets the configuration in challenge-response, OTP mode.
    pub fn challenge_response_otp(&mut self, secret: &Aes128Key, priv_id: &[u8;6], button: bool) {
        self.tkt_flags = TicketFlags::empty();
        self.cfg_flags = ConfigFlags::empty();
        self.ext_flags = ExtendedFlags::empty();

        self.tkt_flags.insert(TicketFlags::CHAL_RESP);
        self.cfg_flags.insert(if button { ConfigFlags::CHAL_YUBICO | ConfigFlags::CHAL_BTN_TRIG } else { ConfigFlags::CHAL_YUBICO });

        self.uid.copy_from_slice(priv_id);
        self.key.copy_from_slice(&secret.0);
    }
}

bitflags! {
    pub struct TicketFlags: u8 {
        const TAB_FIRST = 0x1;
        const APPEND_TAB1 = 0x2;
        const APPEND_TAB2 = 0x4;
        const APPEND_DELAY1 = 0x8;
        const APPEND_DELAY2 = 0x10;
        const APPEND_CR = 0x20;
        const OATH_HOTP = 0x40;
        const CHAL_RESP = 0x40;
        const PROTECT_CFG2 = 0x80;
    }
}

bitflags! {
    pub struct ConfigFlags: u8 {
        // Yubikey 1.0
        const SEND_REF = 0x1;
        const TICKET_FIRST = 0x2;
        const PACING_10MS = 0x4;
        const PACING_20MS = 0x8;
        const STATIC_TICKET = 0x20;
        // YubiKey >= 2.0
        const SHORT_TICKET = 0x2;
        const STRONG_PW1 = 0x10;
        const STRONG_PW2 = 0x40;
        const MAN_UPDATE = 0x80;
        // YubiKey >= 2.1
        const OATH_HOTP8 = 0x2;
        const OATH_FIXED_MODHEX1 = 0x10;
        const OATH_FIXED_MODHEX2 = 0x40;
        const OATH_FIXED_MODHEX = 0x50;
        const OATH_FIXED_MASK = 0x50;
        // YubiKey >= 2.2
        const CHAL_YUBICO = 0x20;
        const CHAL_HMAC = 0x22;
        const HMAC_LT64 = 0x04;
        const CHAL_BTN_TRIG = 0x08;
    }
}

bitflags! {
    pub struct ExtendedFlags: u8 {
        const SERIAL_BTN_VISIBLE = 0x01;
        const SERIAL_USB_VISIBLE = 0x02;
        const SERIAL_API_VISIBLE = 0x04;
        // YubiKey >= 2.3
        const USE_NUMERIC_KEYPAD = 0x08;
        const FAST_TRIG = 0x10;
        const ALLOW_UPDATE = 0x20;
        const DORMANT = 0x40;
    }
}