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use super::commands::get_assertion::HmacSecretExtension;
use crate::crypto::{COSEAlgorithm, CryptoError, PinUvAuthToken, SharedSecret};
use crate::{errors::AuthenticatorError, AuthenticatorTransports, KeyHandle};
use base64::Engine;
use serde::de::MapAccess;
use serde::{
de::{Error as SerdeError, Unexpected, Visitor},
Deserialize, Deserializer, Serialize, Serializer,
};
use serde_bytes::{ByteBuf, Bytes};
use sha2::{Digest, Sha256};
use std::collections::HashMap;
use std::convert::{Into, TryFrom};
use std::fmt;
#[derive(Serialize, Deserialize, PartialEq, Eq, Clone)]
pub struct RpIdHash(pub [u8; 32]);
impl fmt::Debug for RpIdHash {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let value = base64::engine::general_purpose::URL_SAFE_NO_PAD.encode(self.0);
write!(f, "RpIdHash({value})")
}
}
impl AsRef<[u8]> for RpIdHash {
fn as_ref(&self) -> &[u8] {
self.0.as_ref()
}
}
impl RpIdHash {
pub fn from(src: &[u8]) -> Result<RpIdHash, AuthenticatorError> {
let mut payload = [0u8; 32];
if src.len() != payload.len() {
Err(AuthenticatorError::InvalidRelyingPartyInput)
} else {
payload.copy_from_slice(src);
Ok(RpIdHash(payload))
}
}
}
// NOTE: WebAuthn requires all fields and CTAP2 does not.
#[derive(Debug, Serialize, Clone, Default, Deserialize, PartialEq, Eq)]
pub struct RelyingParty {
pub id: String,
#[serde(skip_serializing_if = "Option::is_none")]
pub name: Option<String>,
}
impl RelyingParty {
pub fn from<S>(id: S) -> Self
where
S: Into<String>,
{
Self {
id: id.into(),
name: None,
}
}
pub fn hash(&self) -> RpIdHash {
RpIdHash(Sha256::digest(&self.id).into())
}
}
// NOTE: WebAuthn requires all fields and CTAP2 does not.
#[derive(Debug, Serialize, Clone, Eq, PartialEq, Deserialize, Default)]
pub struct PublicKeyCredentialUserEntity {
#[serde(with = "serde_bytes")]
pub id: Vec<u8>,
pub name: Option<String>,
#[serde(skip_serializing_if = "Option::is_none", rename = "displayName")]
pub display_name: Option<String>,
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PublicKeyCredentialParameters {
pub alg: COSEAlgorithm,
}
impl TryFrom<i32> for PublicKeyCredentialParameters {
type Error = AuthenticatorError;
fn try_from(arg: i32) -> Result<Self, Self::Error> {
let alg = COSEAlgorithm::try_from(arg as i64)?;
Ok(PublicKeyCredentialParameters { alg })
}
}
impl Serialize for PublicKeyCredentialParameters {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
serialize_map!(
serializer,
"alg" => &self.alg,
"type" => "public-key",
)
}
}
impl<'de> Deserialize<'de> for PublicKeyCredentialParameters {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: Deserializer<'de>,
{
struct PublicKeyCredentialParametersVisitor;
impl<'de> Visitor<'de> for PublicKeyCredentialParametersVisitor {
type Value = PublicKeyCredentialParameters;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("a map")
}
fn visit_map<M>(self, mut map: M) -> Result<Self::Value, M::Error>
where
M: MapAccess<'de>,
{
let mut found_type = false;
let mut alg = None;
while let Some(key) = map.next_key()? {
match key {
"alg" => {
if alg.is_some() {
return Err(SerdeError::duplicate_field("alg"));
}
alg = Some(map.next_value()?);
}
"type" => {
if found_type {
return Err(SerdeError::duplicate_field("type"));
}
let v: &str = map.next_value()?;
if v != "public-key" {
return Err(SerdeError::custom(format!("invalid value: {v}")));
}
found_type = true;
}
v => {
return Err(SerdeError::unknown_field(v, &[]));
}
}
}
if !found_type {
return Err(SerdeError::missing_field("type"));
}
let alg = alg.ok_or_else(|| SerdeError::missing_field("alg"))?;
Ok(PublicKeyCredentialParameters { alg })
}
}
deserializer.deserialize_bytes(PublicKeyCredentialParametersVisitor)
}
}
#[derive(Debug, PartialEq, Serialize, Deserialize, Eq, Clone)]
#[serde(rename_all = "lowercase")]
pub enum Transport {
USB,
NFC,
BLE,
Internal,
}
impl From<AuthenticatorTransports> for Vec<Transport> {
fn from(t: AuthenticatorTransports) -> Self {
let mut transports = Vec::new();
if t.contains(AuthenticatorTransports::USB) {
transports.push(Transport::USB);
}
if t.contains(AuthenticatorTransports::NFC) {
transports.push(Transport::NFC);
}
if t.contains(AuthenticatorTransports::BLE) {
transports.push(Transport::BLE);
}
transports
}
}
pub type PublicKeyCredentialId = Vec<u8>;
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PublicKeyCredentialDescriptor {
pub id: PublicKeyCredentialId,
pub transports: Vec<Transport>,
}
impl Serialize for PublicKeyCredentialDescriptor {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
serialize_map!(
serializer,
"id" => Bytes::new(&self.id),
"type" => "public-key",
// TODO(MS): Transports is OPTIONAL, but some older tokens don't understand it
// and return a CBOR-Parsing error. It is only a hint for the token,
// so we'll leave it out for the moment
// "transports" => &self.transports,
)
}
}
impl<'de> Deserialize<'de> for PublicKeyCredentialDescriptor {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: Deserializer<'de>,
{
struct PublicKeyCredentialDescriptorVisitor;
impl<'de> Visitor<'de> for PublicKeyCredentialDescriptorVisitor {
type Value = PublicKeyCredentialDescriptor;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("a map")
}
fn visit_map<M>(self, mut map: M) -> Result<Self::Value, M::Error>
where
M: MapAccess<'de>,
{
let mut found_type = false;
let mut id = None;
let mut transports = None;
while let Some(key) = map.next_key()? {
match key {
"id" => {
if id.is_some() {
return Err(SerdeError::duplicate_field("id"));
}
let id_bytes: ByteBuf = map.next_value()?;
id = Some(id_bytes.into_vec());
}
"transports" => {
if transports.is_some() {
return Err(SerdeError::duplicate_field("transports"));
}
transports = Some(map.next_value()?);
}
"type" => {
if found_type {
return Err(SerdeError::duplicate_field("type"));
}
let v: &str = map.next_value()?;
if v != "public-key" {
return Err(SerdeError::custom(format!("invalid value: {v}")));
}
found_type = true;
}
v => {
return Err(SerdeError::unknown_field(v, &[]));
}
}
}
if !found_type {
return Err(SerdeError::missing_field("type"));
}
let id = id.ok_or_else(|| SerdeError::missing_field("id"))?;
let transports = transports.unwrap_or_default();
Ok(PublicKeyCredentialDescriptor { id, transports })
}
}
deserializer.deserialize_any(PublicKeyCredentialDescriptorVisitor)
}
}
impl From<&KeyHandle> for PublicKeyCredentialDescriptor {
fn from(kh: &KeyHandle) -> Self {
Self {
id: kh.credential.clone(),
transports: kh.transports.into(),
}
}
}
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum ResidentKeyRequirement {
Discouraged,
Preferred,
Required,
}
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum UserVerificationRequirement {
Discouraged,
Preferred,
Required,
}
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum CredentialProtectionPolicy {
UserVerificationOptional = 1,
UserVerificationOptionalWithCredentialIDList = 2,
UserVerificationRequired = 3,
}
impl Serialize for CredentialProtectionPolicy {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
serializer.serialize_u64(*self as u64)
}
}
impl<'de> Deserialize<'de> for CredentialProtectionPolicy {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: Deserializer<'de>,
{
struct CredentialProtectionPolicyVisitor;
impl<'de> Visitor<'de> for CredentialProtectionPolicyVisitor {
type Value = CredentialProtectionPolicy;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("an integer")
}
fn visit_u64<E>(self, v: u64) -> Result<Self::Value, E>
where
E: SerdeError,
{
match v {
1 => Ok(CredentialProtectionPolicy::UserVerificationOptional),
2 => Ok(
CredentialProtectionPolicy::UserVerificationOptionalWithCredentialIDList,
),
3 => Ok(CredentialProtectionPolicy::UserVerificationRequired),
_ => Err(SerdeError::invalid_value(
Unexpected::Unsigned(v),
&"valid CredentialProtectionPolicy",
)),
}
}
}
deserializer.deserialize_any(CredentialProtectionPolicyVisitor)
}
}
#[derive(Clone, Debug, Default)]
pub struct AuthenticationExtensionsClientInputs {
pub app_id: Option<String>,
pub cred_props: Option<bool>,
pub credential_protection_policy: Option<CredentialProtectionPolicy>,
pub enforce_credential_protection_policy: Option<bool>,
pub hmac_create_secret: Option<bool>,
pub hmac_get_secret: Option<HMACGetSecretInput>,
pub min_pin_length: Option<bool>,
pub prf: Option<AuthenticationExtensionsPRFInputs>,
}
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct CredentialProperties {
pub rk: bool,
}
/// Salt inputs for the `hmac-secret` extension.
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct HMACGetSecretInput {
pub salt1: [u8; 32],
pub salt2: Option<[u8; 32]>,
}
/// Decrypted HMAC outputs from the `hmac-secret` extension.
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct HMACGetSecretOutput {
pub output1: [u8; 32],
pub output2: Option<[u8; 32]>,
}
#[derive(Clone, Debug, Default, PartialEq)]
pub struct AuthenticationExtensionsPRFInputs {
pub eval: Option<AuthenticationExtensionsPRFValues>,
pub eval_by_credential: Option<HashMap<Vec<u8>, AuthenticationExtensionsPRFValues>>,
}
impl AuthenticationExtensionsPRFInputs {
/// Select an `eval` or `evalByCredential` entry and calculate hmac-secret salt inputs from those inputs.
///
/// Returns [None] if the `eval` input was not given and no credential in `allow_credentials` matched any `evalByCredential` entry.
/// Otherwise returns the initialized [HmacSecretExtension] and, if an `evalByCredential` entry was used to compute the salt inputs,
/// the [PublicKeyCredentialDescriptor] matching that `evalByCredential` entry.
/// If present, `allowCredentials` SHOULD be set to contain only that [PublicKeyCredentialDescriptor] value.
pub fn calculate<'allow_cred>(
&self,
secret: &SharedSecret,
allow_credentials: &'allow_cred [PublicKeyCredentialDescriptor],
puat: Option<&PinUvAuthToken>,
) -> Result<
Option<(
HmacSecretExtension,
Option<&'allow_cred PublicKeyCredentialDescriptor>,
)>,
CryptoError,
> {
if let Some((selected_credential, ev)) = self.select_eval(allow_credentials) {
let mut hmac_secret = HmacSecretExtension::new(
Self::eval_to_salt(&ev.first).to_vec(),
ev.second
.as_ref()
.map(|second| Self::eval_to_salt(second).to_vec()),
);
hmac_secret.calculate(secret, puat)?;
Ok(Some((hmac_secret, selected_credential)))
} else {
Ok(None)
}
}
/// Select an `evalByCredential` entry matching any element of `allow_credentials`,
/// or otherwise fall back to `eval`, if present, if no match is found.
fn select_eval<'allow_cred>(
&self,
allow_credentials: &'allow_cred [PublicKeyCredentialDescriptor],
) -> Option<(
Option<&'allow_cred PublicKeyCredentialDescriptor>,
&AuthenticationExtensionsPRFValues,
)> {
self.select_credential(allow_credentials)
.map(|(cred, ev)| (Some(cred), ev))
.or(self.eval.as_ref().map(|eval| (None, eval)))
}
/// Select an `evalByCredential` entry matching any element of `allow_credentials`.
fn select_credential<'allow_cred>(
&self,
allow_credentials: &'allow_cred [PublicKeyCredentialDescriptor],
) -> Option<(
&'allow_cred PublicKeyCredentialDescriptor,
&AuthenticationExtensionsPRFValues,
)> {
self.eval_by_credential
.as_ref()
.and_then(|eval_by_credential| {
allow_credentials
.iter()
.find_map(|pkcd| eval_by_credential.get(&pkcd.id).map(|eval| (pkcd, eval)))
})
}
/// Convert a PRF eval input to an hmac-secret salt input.
fn eval_to_salt(eval: &[u8]) -> [u8; 32] {
Sha256::new_with_prefix(b"WebAuthn PRF")
.chain_update([0x00].iter())
.chain_update(eval.iter())
.finalize()
.into()
}
}
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct AuthenticationExtensionsPRFValues {
pub first: Vec<u8>,
pub second: Option<Vec<u8>>,
}
impl From<HMACGetSecretOutput> for AuthenticationExtensionsPRFValues {
fn from(hmac_output: HMACGetSecretOutput) -> Self {
Self {
first: hmac_output.output1.to_vec(),
second: hmac_output.output2.map(|o2| o2.to_vec()),
}
}
}
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct AuthenticationExtensionsPRFOutputs {
pub enabled: Option<bool>,
pub results: Option<AuthenticationExtensionsPRFValues>,
}
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct AuthenticationExtensionsClientOutputs {
pub app_id: Option<bool>,
pub cred_props: Option<CredentialProperties>,
pub hmac_create_secret: Option<bool>,
pub hmac_get_secret: Option<HMACGetSecretOutput>,
pub prf: Option<AuthenticationExtensionsPRFOutputs>,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum AuthenticatorAttachment {
CrossPlatform,
Platform,
Unknown,
}
#[cfg(test)]
mod test {
use super::{
COSEAlgorithm, PublicKeyCredentialDescriptor, PublicKeyCredentialParameters,
PublicKeyCredentialUserEntity, RelyingParty, Transport,
};
use serde_cbor::from_slice;
fn create_user() -> PublicKeyCredentialUserEntity {
PublicKeyCredentialUserEntity {
id: vec![
0x30, 0x82, 0x01, 0x93, 0x30, 0x82, 0x01, 0x38, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x30,
0x82, 0x01, 0x93, 0x30, 0x82, 0x01, 0x38, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x30, 0x82,
0x01, 0x93, 0x30, 0x82,
],
name: Some(String::from("johnpsmith@example.com")),
display_name: Some(String::from("John P. Smith")),
}
}
#[test]
fn serialize_rp() {
let rp = RelyingParty {
id: String::from("Acme"),
name: None,
};
let payload = ser::to_vec(&rp).unwrap();
assert_eq!(
&payload,
&[
0xa1, // map(1)
0x62, // text(2)
0x69, 0x64, // "id"
0x64, // text(4)
0x41, 0x63, 0x6d, 0x65
]
);
}
#[test]
fn test_deserialize_user() {
// This includes an obsolete "icon" field to test that deserialization
// ignores it.
let input = vec
0x63, 0x73, 0x2e, 0x65, 0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65, // ...
0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x30, 0x30, 0x2f, 0x70, 0x2f, // ...
0x61, 0x42, 0x6a, 0x6a, 0x6a, 0x70, 0x71, 0x50, 0x62, 0x2e, // ...
0x70, 0x6e, 0x67, // ...
0x64, // text(4)
0x6e, 0x61, 0x6d, 0x65, // "name"
0x76, // text(22)
0x6a, 0x6f, 0x68, 0x6e, 0x70, 0x73, 0x6d, 0x69, 0x74,
0x68, // "johnpsmith@example.com"
0x40, 0x65, 0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, // ...
0x6f, 0x6d, // ...
0x6b, // text(11)
0x64, 0x69, 0x73, 0x70, 0x6c, 0x61, 0x79, 0x4e, 0x61, 0x6d, // "displayName"
0x65, // ...
0x6d, // text(13)
0x4a, 0x6f, 0x68, 0x6e, 0x20, 0x50, 0x2e, 0x20, 0x53, 0x6d, // "John P. Smith"
0x69, 0x74, 0x68, // ...
];
let expected = create_user();
let actual: PublicKeyCredentialUserEntity = from_slice(&input).unwrap();
assert_eq!(expected, actual);
}
#[test]
fn serialize_user() {
let user = create_user();
let payload = ser::to_vec(&user).unwrap();
println!("payload = {payload:?}");
assert_eq!(
payload,
vec![
0xa3, // map(3)
0x62, // text(2)
0x69, 0x64, // "id"
0x58, 0x20, // bytes(32)
0x30, 0x82, 0x01, 0x93, 0x30, 0x82, 0x01, 0x38, 0xa0, 0x03, // userid
0x02, 0x01, 0x02, 0x30, 0x82, 0x01, 0x93, 0x30, 0x82, 0x01, // ...
0x38, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x30, 0x82, 0x01, 0x93, // ...
0x30, 0x82, // ...
0x64, // text(4)
0x6e, 0x61, 0x6d, 0x65, // "name"
0x76, // text(22)
0x6a, 0x6f, 0x68, 0x6e, 0x70, 0x73, 0x6d, 0x69, 0x74,
0x68, // "johnpsmith@example.com"
0x40, 0x65, 0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, // ...
0x6f, 0x6d, // ...
0x6b, // text(11)
0x64, 0x69, 0x73, 0x70, 0x6c, 0x61, 0x79, 0x4e, 0x61, 0x6d, // "displayName"
0x65, // ...
0x6d, // text(13)
0x4a, 0x6f, 0x68, 0x6e, 0x20, 0x50, 0x2e, 0x20, 0x53, 0x6d, // "John P. Smith"
0x69, 0x74, 0x68, // ...
]
);
}
#[test]
fn serialize_user_nodisplayname() {
let user = PublicKeyCredentialUserEntity {
id: vec![
0x30, 0x82, 0x01, 0x93, 0x30, 0x82, 0x01, 0x38, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x30,
0x82, 0x01, 0x93, 0x30, 0x82, 0x01, 0x38, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x30, 0x82,
0x01, 0x93, 0x30, 0x82,
],
name: Some(String::from("johnpsmith@example.com")),
display_name: None,
};
let payload = ser::to_vec(&user).unwrap();
println!("payload = {payload:?}");
assert_eq!(
payload,
vec![
0xa2, // map(2)
0x62, // text(2)
0x69, 0x64, // "id"
0x58, 0x20, // bytes(32)
0x30, 0x82, 0x01, 0x93, 0x30, 0x82, 0x01, 0x38, 0xa0, 0x03, // userid
0x02, 0x01, 0x02, 0x30, 0x82, 0x01, 0x93, 0x30, 0x82, 0x01, // ...
0x38, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x30, 0x82, 0x01, 0x93, // ...
0x30, 0x82, // ...
0x64, // text(4)
0x6e, 0x61, 0x6d, 0x65, // "name"
0x76, // text(22)
0x6a, 0x6f, 0x68, 0x6e, 0x70, 0x73, 0x6d, 0x69, 0x74,
0x68, // "johnpsmith@example.com"
0x40, 0x65, 0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, // ...
0x6f, 0x6d, // ...
]
);
}
use serde_cbor::ser;
#[test]
fn public_key() {
let keys = vec![
PublicKeyCredentialParameters {
alg: COSEAlgorithm::ES256,
},
PublicKeyCredentialParameters {
alg: COSEAlgorithm::RS256,
},
];
let payload = ser::to_vec(&keys);
println!("payload = {payload:?}");
let payload = payload.unwrap();
assert_eq!(
payload,
vec![
0x82, // array(2)
0xa2, // map(2)
0x63, // text(3)
0x61, 0x6c, 0x67, // "alg"
0x26, // -7 (ES256)
0x64, // text(4)
0x74, 0x79, 0x70, 0x65, // "type"
0x6a, // text(10)
0x70, 0x75, 0x62, 0x6C, 0x69, 0x63, // "public-key"
0x2D, 0x6B, 0x65, 0x79, // ...
0xa2, // map(2)
0x63, // text(3)
0x61, 0x6c, 0x67, // "alg"
0x39, 0x01, 0x00, // -257 (RS256)
0x64, // text(4)
0x74, 0x79, 0x70, 0x65, // "type"
0x6a, // text(10)
0x70, 0x75, 0x62, 0x6C, 0x69, 0x63, // "public-key"
0x2D, 0x6B, 0x65, 0x79 // ...
]
);
}
#[test]
fn public_key_desc() {
let key = PublicKeyCredentialDescriptor {
id: vec![
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d,
0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b,
0x1c, 0x1d, 0x1e, 0x1f,
],
transports: vec![Transport::BLE, Transport::USB],
};
let payload = ser::to_vec(&key);
println!("payload = {payload:?}");
let payload = payload.unwrap();
assert_eq!(
payload,
vec![
// 0xa3, // map(3)
0xa2, // map(2)
0x62, // text(2)
0x69, 0x64, // "id"
0x58, 0x20, // bytes(32)
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, // key id
0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, // ...
0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, // ...
0x12, 0x13, 0x14, 0x15, 0x16, 0x17, // ...
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, // ...
0x1e, 0x1f, // ...
0x64, // text(4)
0x74, 0x79, 0x70, 0x65, // "type"
0x6a, // text(10)
0x70, 0x75, 0x62, 0x6C, 0x69, 0x63, // "public-key"
0x2D, 0x6B, 0x65,
0x79, // ...
// Deactivated for now
//0x6a, // text(10)
//0x74, 0x72, 0x61, 0x6e, 0x73, 0x70, // "transports"
//0x6f, 0x72, 0x74, 0x73, // ...
//0x82, // array(2)
//0x63, // text(3)
//0x62, 0x6c, 0x65, // "ble"
//0x63, // text(3)
//0x75, 0x73, 0x62 // "usb"
]
);
}
}