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use std::fmt; use url::{form_urlencoded, Url}; mod error; mod hotp; mod totp; #[cfg(test)] mod tests; pub use self::error::*; use crate::otp::hotp::HOTPGenerator; use crate::otp::totp::TOTPGenerator; use std::str::FromStr; use zeroize::Zeroize; const OTP_URL_SCHEME: &str = "otpauth"; pub enum OTPType { Totp { period: u32 }, Hotp { counter: u64 }, } impl fmt::Display for OTPType { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match self { OTPType::Totp { .. } => write!(f, "totp")?, OTPType::Hotp { .. } => write!(f, "hotp")?, } Ok(()) } } #[derive(Clone, Copy, Debug, PartialEq, Eq)] pub enum OTPAlgorithm { SHA1, SHA256, SHA512, } impl fmt::Display for OTPAlgorithm { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match self { OTPAlgorithm::SHA1 => write!(f, "SHA1")?, OTPAlgorithm::SHA256 => write!(f, "SHA256")?, OTPAlgorithm::SHA512 => write!(f, "SHA512")?, } Ok(()) } } #[derive(Zeroize)] #[zeroize(drop)] pub struct OTPSecret(Vec<u8>); impl ToString for OTPSecret { fn to_string(&self) -> String { data_encoding::BASE32_NOPAD.encode(&self.0) } } impl FromStr for OTPSecret { type Err = OTPError; fn from_str(s: &str) -> OTPResult<Self> { match data_encoding::BASE32_NOPAD.decode(s.as_bytes()) { Ok(bytes) => Ok(OTPSecret(bytes)), Err(_) => Err(OTPError::InvalidSecret), } } } pub struct OTPAuthUrl { pub otp_type: OTPType, pub algorithm: OTPAlgorithm, pub digits: u8, pub account_name: String, pub issuer: Option<String>, pub secret: OTPSecret, } impl OTPAuthUrl { pub fn parse<S: AsRef<str>>(url_str: S) -> OTPResult<OTPAuthUrl> { let url = Url::parse(url_str.as_ref())?; if url.scheme() != OTP_URL_SCHEME { return Err(OTPError::InvalidScheme); } let otp_type = match url.host_str() { Some("totp") => { let period = Self::find_parameter(&url, "period")?.unwrap_or(30); OTPType::Totp { period } } Some("hotp") => { let counter = Self::find_required_parameter(&url, "counter")?; OTPType::Hotp { counter } } _ => return Err(OTPError::InvalidType), }; let mut issuer = Self::find_parameter::<String>(&url, "issuer")?; let mut account_name = String::new(); if url.path().is_empty() { return Err(OTPError::MissingParameter("accountname".to_string())); } else { let mut parts = url.path()[1..].split(':'); if let Some(issuer_or_account) = parts.next() { account_name = issuer_or_account.to_string(); } if let Some(account) = parts.next() { issuer = Some(account_name); account_name = account.to_string(); } } let algorithm = match Self::find_parameter::<String>(&url, "algorithm")?.as_deref() { Some("SHA1") | None => OTPAlgorithm::SHA1, Some("SHA256") => OTPAlgorithm::SHA256, Some("SHA512") => OTPAlgorithm::SHA512, Some(_) => return Err(OTPError::InvalidAlgorithm), }; let digits = Self::find_parameter(&url, "digits")?.unwrap_or(6); let secret = Self::find_required_parameter(&url, "secret")?; Ok(OTPAuthUrl { otp_type, algorithm, digits, account_name, issuer, secret, }) } pub fn to_url(&self) -> String { let mut result = format!("{}://{}/", OTP_URL_SCHEME, self.otp_type.to_string()); if let Some(issuer) = &self.issuer { result.extend(form_urlencoded::byte_serialize(issuer.as_bytes())); result += ":" } result.extend(form_urlencoded::byte_serialize(self.account_name.as_bytes())); result += "?secret="; result += &self.secret.to_string(); match self.otp_type { OTPType::Totp { period } if period != 30 => result += &format!("&period={}", period), OTPType::Totp { .. } => (), OTPType::Hotp { counter } => result += &format!("&counter={}", counter), } if self.digits != 6 { result += &format!("&digits={}", self.digits); } if let Some(issuer) = &self.issuer { result += "&issuer="; result.extend(form_urlencoded::byte_serialize(issuer.as_bytes())); } if self.algorithm != OTPAlgorithm::SHA1 { result += &format!("&algorithm={}", self.algorithm); } result } pub fn generate(&self, timestamp_or_counter: u64) -> (String, u64) { match self.otp_type { OTPType::Totp { period } => TOTPGenerator { algorithm: self.algorithm, digits: self.digits, period, secret: &self.secret.0, } .generate(timestamp_or_counter), OTPType::Hotp { .. } => HOTPGenerator { algorithm: self.algorithm, digits: self.digits, counter: timestamp_or_counter, secret: &self.secret.0, } .generate(), } } fn find_parameter<T: FromStr>(url: &Url, name: &str) -> OTPResult<Option<T>> { match url.query_pairs().find(|(key, _)| key == name) { Some((_, value)) => { let t = value .parse::<T>() .map_err(|_| OTPError::MissingParameter(name.to_string()))?; Ok(Some(t)) } None => Ok(None), } } fn find_required_parameter<T: FromStr>(url: &Url, name: &str) -> OTPResult<T> { Self::find_parameter(url, name)?.ok_or_else(|| OTPError::MissingParameter(name.to_string())) } }