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17 Commits

12 changed files with 908 additions and 140 deletions

44
Cargo.lock generated
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@ -5,7 +5,7 @@ version = 3
[[package]]
name = "arduino-hal"
version = "0.1.0"
source = "git+https://github.com/rahix/avr-hal#fb609ab0d14c5a0a44e2dff3e5e514cb612a529a"
source = "git+https://github.com/rahix/avr-hal#e29a7be5b1fa9d490ded11e539d345af041ccef6"
dependencies = [
"atmega-hal",
"avr-device",
@ -19,7 +19,7 @@ dependencies = [
[[package]]
name = "atmega-hal"
version = "0.1.0"
source = "git+https://github.com/rahix/avr-hal#fb609ab0d14c5a0a44e2dff3e5e514cb612a529a"
source = "git+https://github.com/rahix/avr-hal#e29a7be5b1fa9d490ded11e539d345af041ccef6"
dependencies = [
"avr-device",
"avr-hal-generic",
@ -33,9 +33,9 @@ checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
[[package]]
name = "avr-device"
version = "0.5.0"
version = "0.5.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "deb45711b7227cb3f799c40c4e0e8beea1765acff8d06a14bb3479c1a549d8b0"
checksum = "644690f9699830f0efce38ca9d41c7ad51a6ec1829364dd272638938c953673a"
dependencies = [
"avr-device-macros",
"bare-metal",
@ -45,9 +45,9 @@ dependencies = [
[[package]]
name = "avr-device-macros"
version = "0.5.0"
version = "0.5.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "87c428a2384981d8460668c48c766ff18e7e91d2d467f7b103151984ee952d38"
checksum = "ba8b49941a5148cec432d5180d205871f0132f9f15b7225a9f3ad9e2bae026cb"
dependencies = [
"proc-macro2",
"quote",
@ -57,7 +57,7 @@ dependencies = [
[[package]]
name = "avr-hal-generic"
version = "0.1.0"
source = "git+https://github.com/rahix/avr-hal#fb609ab0d14c5a0a44e2dff3e5e514cb612a529a"
source = "git+https://github.com/rahix/avr-hal#e29a7be5b1fa9d490ded11e539d345af041ccef6"
dependencies = [
"avr-device",
"cfg-if 0.1.10",
@ -76,12 +76,6 @@ version = "1.0.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "f8fe8f5a8a398345e52358e18ff07cc17a568fbca5c6f73873d3a62056309603"
[[package]]
name = "binascii"
version = "0.1.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "383d29d513d8764dcdc42ea295d979eb99c3c9f00607b3692cf68a431f7dca72"
[[package]]
name = "cfg-if"
version = "0.1.10"
@ -107,8 +101,7 @@ dependencies = [
[[package]]
name = "ds323x"
version = "0.5.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "057e63d03a3beb83d3c9b7a19b799c60e203b0c53f1bbec6a715804907f73a2b"
source = "git+https://github.com/kirbylife/ds323x-rs?branch=fix-set-day-format#e204b77494f921cfc276c9a66e6e9ba95dc4e142"
dependencies = [
"embedded-hal",
"rtcc",
@ -130,6 +123,11 @@ version = "0.2.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "723dce4e9f25b6e6c5f35628e144794e5b459216ed7da97b7c4b66cdb3fa82ca"
[[package]]
name = "hmac-sha1-compact"
version = "1.1.3"
source = "git+https://github.com/kirbylife/rust-hmac-sha1#a3c4116837efb8a850fb0d03985831ce4dc2bc12"
[[package]]
name = "nb"
version = "0.1.3"
@ -184,9 +182,9 @@ checksum = "dc375e1527247fe1a97d8b7156678dfe7c1af2fc075c9a4db3690ecd2a148068"
[[package]]
name = "proc-macro2"
version = "1.0.54"
version = "1.0.56"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e472a104799c74b514a57226160104aa483546de37e839ec50e3c2e41dd87534"
checksum = "2b63bdb0cd06f1f4dedf69b254734f9b45af66e4a031e42a7480257d9898b435"
dependencies = [
"unicode-ident",
]
@ -220,20 +218,14 @@ name = "rustytoken"
version = "0.1.0"
dependencies = [
"arduino-hal",
"binascii",
"chrono",
"ds323x",
"embedded-hal",
"hmac-sha1-compact",
"nb 1.1.0",
"panic-halt",
"sha1_smol",
"ufmt 0.2.0",
]
[[package]]
name = "sha1_smol"
version = "1.0.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "ae1a47186c03a32177042e55dbc5fd5aee900b8e0069a8d70fba96a9375cd012"
[[package]]
name = "syn"
version = "1.0.109"

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@ -4,17 +4,17 @@ version = "0.1.0"
edition = "2021"
[dependencies]
arduino-hal = { git = "https://github.com/rahix/avr-hal", features = ["arduino-uno"] }
arduino-hal = { git = "https://github.com/rahix/avr-hal", features = ["arduino-nano"] }
ds323x = { git = "https://github.com/kirbylife/ds323x-rs", branch = "fix-set-day-format" }
hmac-sha1-compact = { git = "https://github.com/kirbylife/rust-hmac-sha1" }
panic-halt = "0.2.0"
sha1_smol = "1.0.0"
binascii = { version = "0.1", default-features = false, features = ["decode"] }
chrono = { version = "0.4.24", default-features = false }
ds323x = "0.5.0"
embedded-hal = "0.2.7"
nb = "1.1.0"
ufmt = "0.2.0"
[profile.release]
lto = true
panic = "abort"
strip = true
opt-level = "z"
opt-level = "s"
codegen-units = 1

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@ -1,5 +1,38 @@
# RustyToken
# RustyToken (I'm open to new names)
## Converts any Arduino into a TOTP keys
IT's a **TOY** utility to make a TOTP keychain.
This it's a **TOY**, Please don't keep your top priority keys here.
I disclaim any responsability for anything that may happen to your TOTP keys.
You can build a TOTP Key with an Arduino
## Hardware
To make your own RustyToken you'll need:
- 1 Arduino (UNO/Nano)
- 1 RTC DS3231
- 1 Screen STN LCD 16x2 without i2c interface
- 2 push buttons
- 1 220 ohms
- A lot of wire
## Software
To build the firmware for your Arduino you'll need:
- A linux machine (I don't know if this compile on another OS)
- All the rust env tools (rustc, cargo, rustup)
- The Rust's nightly version
- all the AVR env build tools (avr-gcc, avr-binutils, avr-libc, avrdude)
- Python3 to use the tool
## How to build and load the firmware
To build the firmware you execute:
```Bash
$ ./build.sh
```
And to upload it to the Arduino, connect it to the computer and execute:
```Bash
$ ./upload.sh
```
IF this step fails, edit the `upload.sh` script and change the `/dev/ttyUSB0` to the Serial port assiged to your Arduino (You can check this path with the Arduino IDE)
## Diagram
![Diagrama de RustyToken](imgs/diagram.png)

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63
src/button.rs 100644
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@ -0,0 +1,63 @@
use embedded_hal::digital::v2::InputPin;
pub struct Button<'a, P> {
pin: &'a P,
state: bool,
is_pullup: bool,
}
#[derive(PartialEq)]
pub enum Event {
PressDown,
PressUp,
Pressed,
None,
}
impl<'a, P: InputPin> Button<'a, P> {
pub fn new(pin: &'a P, is_pullup: bool) -> Self {
let mut state = pin.is_high().map_err(|_| ()).unwrap();
if is_pullup {
state = !state;
}
Button {
pin,
state,
is_pullup,
}
}
fn read_pin(&self) -> bool {
let mut inc = 0;
for _ in 0..100 {
let mut state = self.pin.is_high().map_err(|_| ()).unwrap();
if self.is_pullup {
state = !state;
}
if state {
inc += 1;
}
}
inc > 70
}
pub fn update(&mut self) -> Event {
let actual_state = self.read_pin();
match (self.state, actual_state) {
(false, false) => Event::None,
(true, false) => {
self.state = !self.state;
Event::PressUp
}
(false, true) => {
self.state = !self.state;
Event::PressDown
}
(true, true) => Event::Pressed,
}
}
}

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@ -1,40 +1,16 @@
use sha1_smol::Sha1;
use hmac_sha1_compact::HMAC;
const BLOCK_SIZE: usize = 64;
pub const INTERVAL: u64 = 30;
pub fn hmac_sha1(key: &[u8], message: &[u8], output: &mut [u8]) {
// Preprocess the key.
let mut key_padded = [0u8; BLOCK_SIZE];
if key.len() > BLOCK_SIZE {
let mut hash = Sha1::new();
hash.update(key);
let key_digest = hash.digest().bytes();
key_padded[..20].copy_from_slice(&key_digest);
} else {
key_padded[..key.len()].copy_from_slice(key);
}
for byte in &mut key_padded {
*byte ^= 0x36;
}
pub fn generate_otp_token(private_key: &[u8], actual_time: u64) -> u32 {
let interval = actual_time / INTERVAL;
let msg = interval.to_be_bytes();
// Hash the inner padded key and the message.
let mut hash = Sha1::new();
hash.update(&key_padded[..]);
hash.update(message);
let mut inner_hash = [0u8; 20];
inner_hash.copy_from_slice(&hash.digest().bytes());
let hmac_digest = HMAC::mac(&msg, private_key);
// Preprocess the key again.
for byte in &mut key_padded {
*byte ^= 0x36 ^ 0x5c;
}
let start = (hmac_digest[19] & 0xF) as usize;
let bytes: [u8; 4] = hmac_digest[start..start + 4].try_into().unwrap();
// Hash the outer padded key and the inner hash.
let mut hash = Sha1::new();
hash.update(&key_padded[..]);
hash.update(&inner_hash[..]);
let hmac_digest = hash.digest().bytes();
// Copy the result into the output buffer.
output.copy_from_slice(&hmac_digest);
let raw_token = u32::from_be_bytes(bytes);
((raw_token & 0x7F_FF_FF_FF) % 1_000_000) as u32
}

124
src/datetime.rs 100644
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@ -0,0 +1,124 @@
// This code was extracted from http://git.musl-libc.org/cgit/musl/tree/src/time?h=v0.9.15
pub struct Datetime {
pub year: u16,
pub month: u8,
pub day: u8,
pub hours: u8,
pub minutes: u8,
pub seconds: u8,
}
impl Datetime {
pub fn unix_epoch(&self) -> u64 {
let year: i64 = self.year as i64 - 1900;
let month: i64 = self.month as i64 - 1;
let (mut t, is_leap) = year_to_secs(year);
t += month_to_secs(month, is_leap);
t += 86400 * (self.day as i64 - 1);
t += 3600 * self.hours as i64;
t += 60 * self.minutes as i64;
t += self.seconds as i64;
t as u64
}
pub fn from_ds3231<T: ds323x::Rtcc>(rtc: &mut T) -> Self {
let year = rtc.year().map_err(|_| ()).unwrap();
let month = rtc.month().map_err(|_| ()).unwrap();
let day = rtc.day().map_err(|_| ()).unwrap();
let hours = match rtc.hours().map_err(|_| ()).unwrap() {
ds323x::Hours::AM(val) => val,
ds323x::Hours::PM(val) => val + 12,
ds323x::Hours::H24(val) => val,
};
let minutes = rtc.minutes().map_err(|_| ()).unwrap();
let seconds = rtc.seconds().map_err(|_| ()).unwrap();
Datetime {
year,
month,
day,
hours,
minutes,
seconds,
}
}
}
fn year_to_secs(year: i64) -> (i64, bool) {
let is_leap: bool;
let res: i64;
let mut cycles: i64;
let centuries: i64;
let mut leaps: i64;
let mut rem: i64;
cycles = (year - 100) / 400;
rem = (year - 100) % 400;
if rem < 0 {
cycles -= 1;
rem += 400;
}
if rem == 0 {
is_leap = true;
centuries = 0;
leaps = 0;
} else {
if rem >= 200 {
if rem >= 300 {
centuries = 3;
rem -= 300;
} else {
centuries = 2;
rem -= 200;
}
} else {
if rem >= 100 {
centuries = 1;
rem -= 100;
} else {
centuries = 0;
}
}
if rem == 0 {
is_leap = false;
leaps = 0;
} else {
leaps = rem / 4;
rem %= 4;
is_leap = rem == 0;
}
}
leaps += 97 * cycles + 24 * centuries - (is_leap as i64);
res = (year - 100) * 31536000 + leaps * 86400 + 946684800 + 86400;
(res, is_leap)
}
fn month_to_secs(month: i64, is_leap: bool) -> i64 {
const SECS_THROUGH_MONTH: [i64; 12] = [
0, // Jan
31 * 86400, // Feb
59 * 86400, // Mar
90 * 86400, // Apr
120 * 86400, // May
151 * 86400, // Jun
181 * 86400, // Jul
212 * 86400, // Aug
243 * 86400, // Sep
273 * 86400, // Oct
304 * 86400, // Nov
334 * 86400, // Dec
];
let mut t = SECS_THROUGH_MONTH[month as usize];
if is_leap && month >= 2 {
t += 86400;
}
t
}

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@ -1,70 +1,35 @@
#![no_std]
#![no_main]
mod button;
mod crypto;
mod datetime;
mod screen;
mod storage;
use arduino_hal::default_serial;
use arduino_hal::delay_ms;
use crypto::hmac_sha1;
use ds323x::DateTimeAccess;
// use arduino_hal::delay_ms;
use arduino_hal::prelude::*;
use crypto::generate_otp_token;
use crypto::INTERVAL;
use ds323x::Rtcc;
use nb::block;
use panic_halt as _;
use storage::SECRET_KEY_MAX_LEN;
use storage::SECRET_KEY_NAME_LEN;
const INTERVAL: i64 = 30;
const SECRET_KEY_MAX_LEN: usize = 32;
fn process_secret<'a>(secret: &str, output: &mut [u8]) -> usize {
// RFC 6238 Doesn't specify a max length for the secret keys, So I chose 32
// You can change the max length by modifying the const
let mut result = [0u8; SECRET_KEY_MAX_LEN];
let mut inc = 0;
let offset = match 8 - (secret.len() % 8) {
8 => 0,
n => n,
};
for c in secret.chars() {
result[inc] = c.to_ascii_uppercase() as u8;
inc += 1;
}
for _ in 0..offset {
result[inc] = '=' as u8;
inc += 1;
}
let decoded = match binascii::b32decode(&result[..inc], output).ok() {
Some(bytes) => bytes,
None => "".as_bytes(), // TODO: Implement a way to display errors
};
decoded.len()
}
fn generate_otp_token(private_key: &str, actual_time: i64) -> u32 {
let mut output = [0u8; 50];
let private_key_len = process_secret(private_key, &mut output);
let interval = actual_time / INTERVAL;
let msg = interval.to_be_bytes();
let mut hmac_digest = [0u8; 20];
hmac_sha1(&output[..private_key_len], &msg, &mut hmac_digest);
let start = (hmac_digest[19] & 0xF) as usize;
let bytes: [u8; 4] = hmac_digest[start..start + 4].try_into().unwrap();
let raw_token = u32::from_be_bytes(bytes);
((raw_token & 0x7F_FF_FF_FF) % 1_000_000) as u32
}
fn token_to_bytes(mut token: u32, output: &mut [u8]) {
let mut inc = 0;
while token > 0 {
output[inc] = (token % 10) as u8 + b'0';
token /= 10;
inc += 1;
}
output.reverse()
}
const ENDL: u8 = 0;
const OK: u8 = 1;
const ERROR: u8 = 2;
const HANDSHAKE: u8 = 3;
const SET_TIMESTAMP: u8 = 10;
const ADD_TOKEN: u8 = 20;
const DELETE_TOKEN: u8 = 30;
const GET_TOKENS: u8 = 40;
const SOFT_WIPE_TOKENS: u8 = 50;
const HARD_WIPE_TOKENS: u8 = 60;
const EXIT: u8 = 255;
#[arduino_hal::entry]
fn main() -> ! {
@ -73,26 +38,163 @@ fn main() -> ! {
let mut led = pins.d13.into_output();
let mut serial = default_serial!(dp, pins, 9600);
let i2c = arduino_hal::I2c::new(
let mut rs = pins.d9.into_output();
let mut en = pins.d8.into_output();
let mut d4 = pins.d5.into_output();
let mut d5 = pins.d4.into_output();
let mut d6 = pins.d3.into_output();
let mut d7 = pins.d2.into_output();
let mut display = screen::StnScreen::new(&mut rs, &mut en, &mut d4, &mut d5, &mut d6, &mut d7);
display.clear();
let i2c_clock = arduino_hal::I2c::new(
dp.TWI,
pins.a4.into_pull_up_input(),
pins.a5.into_pull_up_input(),
pins.a4.into_pull_up_input(), // SDA
pins.a5.into_pull_up_input(), // SCL
50000,
);
let mut rtc = ds323x::Ds323x::new_ds3231(i2c);
let mut rtc = ds323x::Ds323x::new_ds3231(i2c_clock);
let timestamp = rtc.datetime().unwrap().timestamp();
let timestamp = 0;
let mut eeprom = arduino_hal::Eeprom::new(dp.EEPROM);
let mut tokens = storage::Tokens::new(&mut eeprom);
ufmt::uwriteln!(&mut serial, "timestamp: {}", timestamp).unwrap();
let up = pins.a2.into_pull_up_input();
let mut up_button = button::Button::new(&up, true);
let down = pins.a1.into_pull_up_input();
let mut down_button = button::Button::new(&down, true);
// let token = generate_otp_token("holaaaaamundo", timestamp.try_into().unwrap());
let token = generate_otp_token("aaaaaaaa", timestamp);
up_button.update();
if up_button.update() == button::Event::Pressed || tokens.current.is_none() {
display.write_str("Connected to");
display.set_cursor(0, 1);
display.write_str("USB...");
loop {
// Waiting from a command from the tool
let cmd = block!(serial.read()).unwrap_or(u8::MAX);
ufmt::uwriteln!(&mut serial, "token: {}", token).unwrap();
match cmd {
HANDSHAKE => serial.write(OK).unwrap(),
SET_TIMESTAMP => {
serial.write(OK).unwrap();
let year = block!(serial.read()).unwrap();
let month = block!(serial.read()).unwrap();
let day = block!(serial.read()).unwrap();
let hours = block!(serial.read()).unwrap();
let minutes = block!(serial.read()).unwrap();
let seconds = block!(serial.read()).unwrap();
rtc.set_year(year as u16 + 2000).unwrap();
rtc.set_month(month).unwrap();
rtc.set_day(day).unwrap();
rtc.set_hours(ds323x::Hours::H24(hours)).unwrap();
rtc.set_minutes(minutes).unwrap();
rtc.set_seconds(seconds).unwrap();
serial.write(OK).unwrap();
}
ADD_TOKEN => match tokens.search_free() {
Some(index) => {
serial.write(OK).unwrap();
let mut name_buff = [0u8; SECRET_KEY_NAME_LEN as usize];
for i in 0..name_buff.len() {
let ch = block!(serial.read()).unwrap();
if ch == ENDL {
break;
} else {
name_buff[i] = ch;
}
}
let mut key_buff = [0u8; SECRET_KEY_MAX_LEN as usize];
for i in 0..key_buff.len() {
let ch = block!(serial.read()).unwrap();
if ch == ENDL {
break;
} else {
key_buff[i] = ch;
}
}
match tokens.write(index, &name_buff, &key_buff) {
Ok(_) => serial.write(OK).unwrap(),
Err(_) => serial.write(ERROR).unwrap(),
}
}
None => serial.write(ERROR).unwrap(),
},
SOFT_WIPE_TOKENS => {
serial.write(OK).unwrap();
let deleted_tokens = tokens.soft_wipe_all_tokens();
serial.write(deleted_tokens).unwrap();
serial.write(OK).unwrap();
}
HARD_WIPE_TOKENS => {
serial.write(OK).unwrap();
tokens.hard_wipe_all_tokens();
serial.write(OK).unwrap();
}
EXIT => break,
_ => {}
}
}
}
let mut last_time = 0;
let mut changed = false;
loop {
led.toggle();
delay_ms(1000);
let timestamp = datetime::Datetime::from_ds3231(&mut rtc).unix_epoch();
if up_button.update() == button::Event::PressUp {
changed = true;
tokens.next();
}
if down_button.update() == button::Event::PressUp {
changed = true;
tokens.prev();
}
let curr_time = INTERVAL - (timestamp % INTERVAL);
if curr_time == last_time {
delay_ms(10);
continue;
}
last_time = curr_time;
display.set_cursor(12, 1);
display.write_str(" ");
display.set_cursor(12, 1);
display.write_u8(curr_time as u8);
if changed {
display.set_cursor(0, 0);
display.write_str(" ");
changed = false;
}
match tokens.current {
Some(index) => {
let mut buff_name = [0u8; SECRET_KEY_NAME_LEN as usize];
let mut buff_key = [0u8; SECRET_KEY_MAX_LEN as usize];
match tokens.read(index, &mut buff_name, &mut buff_key) {
Ok((len_name, len_key)) => {
let name = core::str::from_utf8(&buff_name[..len_name]).unwrap();
let key = &buff_key[..len_key];
let token = generate_otp_token(key, timestamp);
display.set_cursor(0, 0);
display.write_str(name);
display.set_cursor(0, 1);
display.write_token(token);
}
_ => {
display.clear();
display.set_cursor(0, 0);
display.write_str("ERROR");
}
}
}
_ => {}
}
changed = false;
}
}

179
src/screen.rs 100644
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@ -0,0 +1,179 @@
use arduino_hal::delay_ms;
use arduino_hal::delay_us;
use embedded_hal::digital::v2::OutputPin;
// The CMDs codes are documented here:
// https://www.openhacks.com/uploadsproductos/eone-1602a1.pdf
const INIT_CMD: u8 = 0x03; // 0b00000011
const MODE_4_BITS_CMD: u8 = 0x02; // 0b00000010
const DISPLAY_MODE_16X2_CMD: u8 = 0x28; // 0b00101000
const ENABLE_SCREEN_CMD: u8 = 0x0C; // 0b00001100
const CLEAN_SCREEN_CMD: u8 = 0x01; // 0b00000001
const SHIFT_LEFT_CMD: u8 = 0x10; // 0b10000
const SHIFT_RIGHT_CMD: u8 = 0x14; // 0b10100
const MOVE_CURSOR_CMD: u8 = 0x80; // 0b10000000
const ROW_OFFSETS: [u8; 2] = [0x00, 0x40];
pub enum Direction {
Left = SHIFT_LEFT_CMD as isize,
Right = SHIFT_RIGHT_CMD as isize,
}
pub struct StnScreen<'a, RS, EN, D4, D5, D6, D7> {
rs: &'a mut RS,
en: &'a mut EN,
d4: &'a mut D4,
d5: &'a mut D5,
d6: &'a mut D6,
d7: &'a mut D7,
}
impl<
'a,
RS: OutputPin,
EN: OutputPin,
D4: OutputPin,
D5: OutputPin,
D6: OutputPin,
D7: OutputPin,
> StnScreen<'a, RS, EN, D4, D5, D6, D7>
{
pub fn new(
rs: &'a mut RS,
en: &'a mut EN,
d4: &'a mut D4,
d5: &'a mut D5,
d6: &'a mut D6,
d7: &'a mut D7,
) -> Self {
let mut display = StnScreen {
rs,
en,
d4,
d5,
d6,
d7,
};
// Initializing of LCM on page 16
// https://z3d9b7u8.stackpathcdn.com/pdf-down/L/C/D/LCD-1602A_CA.pdf
delay_ms(16);
display.write_nibble(INIT_CMD, false);
delay_ms(5);
display.write_nibble(INIT_CMD, false);
delay_us(100);
display.write_nibble(INIT_CMD, false);
delay_us(100);
display.write_nibble(MODE_4_BITS_CMD, false);
delay_us(100);
display.send_cmd(DISPLAY_MODE_16X2_CMD, false);
display.send_cmd(ENABLE_SCREEN_CMD, false);
display.clear();
display
}
fn pulse_enable(&mut self) {
self.en.set_low().ok();
delay_us(1);
self.en.set_high().ok();
delay_us(1);
self.en.set_low().ok();
delay_us(100);
}
fn send_cmd(&mut self, cmd: u8, is_data: bool) {
self.write_nibble((cmd >> 4) & 0x0F, is_data);
self.write_nibble(cmd & 0x0F, is_data);
delay_ms(10);
}
fn write_nibble(&mut self, nibble: u8, is_data: bool) {
self.rs.set_state(is_data.into()).ok();
self.d4.set_state(last_bit(nibble >> 0).into()).ok();
self.d5.set_state(last_bit(nibble >> 1).into()).ok();
self.d6.set_state(last_bit(nibble >> 2).into()).ok();
self.d7.set_state(last_bit(nibble >> 3).into()).ok();
self.pulse_enable();
}
pub fn clear(&mut self) {
self.send_cmd(CLEAN_SCREEN_CMD, false);
}
pub fn shift(&mut self, dir: Direction) {
let cmd = dir as u8;
self.send_cmd(cmd, false);
}
pub fn set_cursor(&mut self, col: u8, row: u8) {
let row_offset = ROW_OFFSETS[row as usize];
let address_position = row_offset | col;
self.send_cmd(MOVE_CURSOR_CMD | address_position, false);
}
pub fn write_char(&mut self, c: char) {
let c = c as u8;
self.write_nibble((c >> 4) & 0x0F, true);
self.write_nibble(c & 0x0F, true);
delay_us(100);
}
pub fn write_str<S: AsRef<str>>(&mut self, s: S) {
let s = s.as_ref();
for c in s.chars() {
self.write_char(c);
}
}
pub fn write_token(&mut self, mut token: u32) {
let mut buff = [0u8; 7];
for (n, chr) in buff.iter_mut().enumerate() {
*chr = if n == 3 {
'-' as u8
} else {
let ch = (token % 10) as u8 + '0' as u8;
token /= 10;
ch
}
}
buff.reverse();
let s = core::str::from_utf8(&buff).unwrap();
self.write_str(s);
}
pub fn write_u8(&mut self, mut num: u8) {
if num == 0 {
self.write_char('0');
return;
}
let mut buff = [0u8; 3];
let num_len = num.ilog10() as usize;
for i in (0..=num_len).rev() {
buff[i] = num % 10 + '0' as u8;
num /= 10;
}
self.write_str(core::str::from_utf8(&buff[..=num_len]).unwrap());
}
pub fn write_u32(&mut self, mut num: u32) {
if num == 0 {
self.write_char('0');
return;
}
let mut buff = [0u8; 10];
let num_len = num.ilog10() as usize;
for i in (0..=num_len).rev() {
buff[i] = (num % 10) as u8 + '0' as u8;
num /= 10;
}
self.write_str(core::str::from_utf8(&buff[..=num_len]).unwrap());
}
}
fn last_bit(n: u8) -> bool {
(n & 1) != 0
}

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src/storage.rs 100644
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use arduino_hal::eeprom::Eeprom;
pub const SECRET_KEY_MAX_LEN: u16 = 32;
pub const SECRET_KEY_NAME_LEN: u16 = 16;
pub const SECRET_KEY_FULL_LEN: u16 = SECRET_KEY_MAX_LEN + SECRET_KEY_NAME_LEN;
pub const ENDL: u8 = 0;
pub struct Tokens<'a> {
mem: &'a mut Eeprom,
pub current: Option<u16>,
capacity: u16,
}
impl<'a> Tokens<'a> {
pub fn new(mem: &'a mut Eeprom) -> Self {
let capacity = mem.capacity() / SECRET_KEY_FULL_LEN;
let mut tokens = Tokens {
mem,
capacity,
current: None,
};
tokens.current = tokens.first();
tokens
}
pub fn search_free(&self) -> Option<u16> {
for n in 0..self.capacity {
let index = SECRET_KEY_FULL_LEN * n;
if self.mem.read_byte(index) == ENDL {
return Some(n);
}
}
None
}
fn first(&self) -> Option<u16> {
for n in 0..self.capacity {
let index = SECRET_KEY_FULL_LEN * n;
if self.mem.read_byte(index) != ENDL {
return Some(n);
}
}
return None;
}
pub fn next(&mut self) -> Option<u16> {
let mut index = self.current.unwrap();
for _ in 0..self.capacity {
index = (index + 1) % self.capacity;
if self.mem.read_byte(index * SECRET_KEY_FULL_LEN) != ENDL {
self.current = Some(index);
return Some(index);
}
}
None
}
pub fn prev(&mut self) -> Option<u16> {
let mut index = self.current.unwrap();
for _ in 0..self.capacity {
index = (index - 1) % self.capacity;
if self.mem.read_byte(index * SECRET_KEY_FULL_LEN) != ENDL {
self.current = Some(index);
return Some(index);
}
}
None
}
pub fn read(&self, index: u16, name: &mut [u8], key: &mut [u8]) -> Result<(usize, usize), ()> {
name.fill(0);
key.fill(0);
let index_name = index * SECRET_KEY_FULL_LEN;
let index_key = (index * SECRET_KEY_FULL_LEN) + SECRET_KEY_NAME_LEN;
self.mem.read(index_name, name).map_err(|_| ())?;
self.mem.read(index_key, key).map_err(|_| ())?;
let len_name = name
.iter()
.position(|&n| n == 0)
.unwrap_or(SECRET_KEY_NAME_LEN as usize);
let len_key = key
.iter()
.position(|&n| n == 0)
.unwrap_or(SECRET_KEY_MAX_LEN as usize);
Ok((len_name, len_key))
}
pub fn write(&mut self, index: u16, name: &[u8], key: &[u8]) -> Result<u16, ()> {
let index_name = index * SECRET_KEY_FULL_LEN;
let index_key = (index * SECRET_KEY_FULL_LEN) + SECRET_KEY_NAME_LEN;
self.mem.write(index_name, name).map_err(|_| ())?;
self.mem.write(index_key, key).map_err(|_| ())?;
Ok(index)
}
pub fn delete(&mut self, index: u16) -> Option<u16> {
// The Arduino's EEPROM memory has a maximum number of write cycles.
// To keep writes to a minimum, only the first byte of the token name is set to 0
// and wipe all the secret key
let index_token = index * SECRET_KEY_FULL_LEN;
let index_key_start = index_token + SECRET_KEY_NAME_LEN;
let index_key_end = index_key_start + SECRET_KEY_MAX_LEN - 1;
self.mem.write_byte(index_token, ENDL);
for index in index_key_start..index_key_end {
self.mem.write_byte(index, ENDL);
}
Some(index)
}
pub fn soft_wipe_all_tokens(&mut self) -> u8 {
let mut inc = 0;
for n in 0..self.capacity {
let index = SECRET_KEY_FULL_LEN * n;
if self.mem.read_byte(index) != ENDL {
self.delete(index);
inc += 1;
}
}
inc
}
pub fn hard_wipe_all_tokens(&mut self) {
for index in 0..self.mem.capacity() {
self.mem.write_byte(index, ENDL);
}
}
}

163
tools/menu.py 100644
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@ -0,0 +1,163 @@
from datetime import datetime
from time import sleep
from typing import Any
import base64
import serial
import sys
ENDL = bytes([0])
OK = bytes([1])
ERROR = bytes([2])
HANDSHAKE = bytes([3])
SET_TIMESTAMP = bytes([10])
ADD_TOKEN = bytes([20])
DELETE_TOKEN = bytes([30])
GET_TOKENS = bytes([40])
SOFT_WIPE_TOKENS = bytes([50])
HARD_WIPE_TOKENS = bytes([60])
EXIT = bytes([255])
def loop_input(msg: str, valid_values: Any) -> str:
valid_values = list(map(str, valid_values))
while True:
data = input(msg)
if data not in valid_values:
print(f"'{data}' isn't a valid value, please enter a value in {valid_values}")
else:
break
return data
def b(n: int) -> bytes:
return bytes([n])
def process_secret(secret: str) -> bytes:
offset = 8 - (len(secret) % 8)
if offset != 8:
secret += "=" * offset
return base64.b32decode(secret, casefold=True)
def get_datetime_items() -> dict[str, bytes]:
now = datetime.utcnow()
return {
"year": b(now.year - 2000),
"month": b(now.month),
"day": b(now.day),
"hours": b(now.hour),
"minutes": b(now.minute),
"seconds": b(now.second)
}
def main(argv: list[str]):
port = argv[-1]
conn = serial.Serial(port=port, baudrate=9600)
print("UP + Reset to enable the USB connection")
input("Press Enter if the device in the USB mode...")
conn.write(HANDSHAKE)
sleep(0.1)
res = conn.read()
if res != OK:
print("A handshake could not be performed")
print("Check the connection with your Arduino")
return 1
else:
print("Handshake successfully performed")
while True:
print("What do you want to do?")
print("1) Update timestamp")
print("2) Add a new token")
print("3) Remove a token")
print("4) SOFT wipe all tokens")
print("5) HARD WIPE ALL THE TOKENS")
print("6) EXIT")
opt = loop_input(">>> ", range(1, 7))
# Update Timestamp
if opt == "1":
conn.write(SET_TIMESTAMP)
sleep(0.1)
resp = conn.read()
sleep(0.1)
if resp == ERROR:
print(f"Error in the communication: Error {resp}")
continue
date_items = get_datetime_items();
conn.write(date_items["year"])
conn.write(date_items["month"])
conn.write(date_items["day"])
conn.write(date_items["hours"])
conn.write(date_items["minutes"])
conn.write(date_items["seconds"])
resp = conn.read()
if resp != OK:
print(f"Error in the communication: Error {resp}")
else:
print("Timestamp updated successfully!")
# Add token
elif opt == "2":
conn.write(ADD_TOKEN)
sleep(0.1)
resp = conn.read()
if resp == ERROR:
print("The memory of the device is full")
continue
name = input("Enter the name of the new token (16 chars max):\n>>> ")
name = name.strip()[:16].encode("ascii")
key = input("Enter the OTP secret key (32 chars max):\n>>> ")
key = process_secret(key.strip()[:32])
for ch in name:
conn.write(b(ch))
conn.write(ENDL)
for ch in key:
conn.write(b(ch))
conn.write(ENDL)
resp = conn.read()
if resp == ERROR:
print("Error trying to add the token, try again")
else:
print("Token added successfully!")
# Soft wipe tokens
elif opt == "4":
conn.write(SOFT_WIPE_TOKENS)
sleep(0.1)
_ = conn.read()
deleted_tokens = conn.read()
resp = conn.read()
if resp == OK:
print(f"{deleted_tokens} tokens wipped successfully!")
else:
print("Error!!")
# Hard wipe tokens
elif opt == "5":
resp = loop_input("This will erase all the EEPROM, do you want to continue? [Y/N]", ["y", "Y", "n", "N"]).upper()
if resp == "Y":
conn.write(HARD_WIPE_TOKENS)
sleep(0.1)
_ = conn.read()
resp = conn.read()
if resp == OK:
print("All the Eeprom erased successfully!")
else:
print("Error!!")
elif opt == "6":
conn.write(EXIT)
return 0
if __name__ == "__main__":
attrs = sys.argv
if len(attrs) == 1:
print("You need to specify the Arduino's serial port")
print("Example:")
print(f"python {attrs[0]} /dev/ttyUSB0")
sys.exit(1)
sys.exit(main(attrs[1:]))

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@ -1 +1,2 @@
avrdude -p atmega328p -c arduino -P /dev/ttyACM0 -U flash:w:target/avr-atmega328p/release/rustytoken.elf:e
# avrdude -p atmega328p -c arduino -P /dev/ttyACM0 -U flash:w:target/avr-atmega328p/release/rustytoken.elf:e
avrdude -p atmega328p -c arduino -P /dev/ttyUSB0 -U flash:w:target/avr-atmega328p/release/rustytoken.elf:e