ctap/src/cbor.rs
2020-04-13 16:42:45 +02:00

758 lines
25 KiB
Rust

// This file is part of ctap, a Rust implementation of the FIDO2 protocol.
// Copyright (c) Ariën Holthuizen <contact@ardaxi.com>
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.
use cbor_codec::value;
use cbor_codec::value::Value;
use cbor_codec::{Config, Decoder, Encoder, GenericDecoder, GenericEncoder};
use byteorder::{BigEndian, ByteOrder, ReadBytesExt, WriteBytesExt};
use failure::ResultExt;
use std::collections::HashMap;
use std::io::Cursor;
use super::error::*;
pub enum Request<'a> {
MakeCredential(MakeCredentialRequest<'a>),
GetAssertion(GetAssertionRequest<'a>),
GetInfo,
ClientPin(ClientPinRequest<'a>),
}
impl<'a> Request<'a> {
pub fn encode<W: WriteBytesExt>(&self, writer: &mut W) -> FidoResult<()> {
let mut encoder = Encoder::new(writer);
match self {
Request::MakeCredential(req) => req.encode(&mut encoder),
Request::GetAssertion(req) => req.encode(&mut encoder),
Request::GetInfo => encoder
.writer()
.write_u8(0x04)
.context(FidoErrorKind::CborEncode)
.map_err(From::from),
Request::ClientPin(req) => req.encode(&mut encoder),
}
}
pub fn decode<R: ReadBytesExt>(&self, reader: R) -> FidoResult<Response> {
Ok(match self {
Request::MakeCredential(_) => {
Response::MakeCredential(MakeCredentialResponse::decode(reader)?)
}
Request::GetAssertion(_) => {
Response::GetAssertion(GetAssertionResponse::decode(reader)?)
}
Request::GetInfo => Response::GetInfo(GetInfoResponse::decode(reader)?),
Request::ClientPin(_) => Response::ClientPin(ClientPinResponse::decode(reader)?),
})
}
}
#[derive(Debug)]
pub enum Response {
MakeCredential(MakeCredentialResponse),
GetAssertion(GetAssertionResponse),
GetInfo(GetInfoResponse),
ClientPin(ClientPinResponse),
}
#[derive(Default, Debug)]
pub struct MakeCredentialRequest<'a> {
pub client_data_hash: &'a [u8],
pub rp: PublicKeyCredentialRpEntity<'a>,
pub user: PublicKeyCredentialUserEntity<'a>,
pub pub_key_cred_params: &'a [(&'a str, i32)],
pub exclude_list: &'a [PublicKeyCredentialDescriptor],
pub extensions: &'a [(&'a str, &'a Value)],
pub options: Option<AuthenticatorOptions>,
pub pin_auth: Option<[u8; 16]>,
pub pin_protocol: Option<u8>,
}
impl<'a> MakeCredentialRequest<'a> {
pub fn encode<W: WriteBytesExt>(&self, mut encoder: &mut Encoder<W>) -> FidoResult<()> {
encoder
.writer()
.write_u8(0x01)
.context(FidoErrorKind::CborEncode)?; // authenticatorMakeCredential
let mut length = 4;
length += !self.exclude_list.is_empty() as usize;
length += !self.extensions.is_empty() as usize;
length += self
.options
.as_ref()
.map(|opt| opt.encoded())
.unwrap_or(false) as usize;
length += self.pin_auth.is_some() as usize;
length += self.pin_protocol.is_some() as usize;
encoder.object(length)?;
encoder.u8(0x01)?; // clientDataHash
encoder.bytes(&self.client_data_hash)?;
encoder.u8(0x02)?; // rp
self.rp.encode(&mut encoder)?;
encoder.u8(0x03)?; // user
self.user.encode(&mut encoder)?;
encoder.u8(0x04)?; // pubKeyCredParams
encoder.array(self.pub_key_cred_params.len())?;
for (cred_type, alg) in self.pub_key_cred_params {
encoder.object(2)?;
encoder.text("alg")?;
encoder.i32(*alg)?;
encoder.text("type")?;
encoder.text(&cred_type)?;
}
if self.exclude_list.len() > 0 {
encoder.u8(0x05)?; // excludeList
encoder.array(self.exclude_list.len())?;
for item in self.exclude_list {
item.encode(&mut encoder)?;
}
}
if self.extensions.len() > 0 {
encoder.u8(0x06)?; // extensions
encoder.object(self.extensions.len())?;
for (key, value) in self.extensions {
encoder.text(key)?;
let mut generic = GenericEncoder::new(encoder.writer());
generic.value(value)?;
}
}
if let Some(options) = &self.options {
if options.encoded() {
encoder.u8(0x07)?; // options
options.encode(&mut encoder)?;
}
}
if let Some(pin_auth) = &self.pin_auth {
encoder.u8(0x08)?; // pinAuth
encoder.bytes(pin_auth)?;
}
if let Some(pin_protocol) = &self.pin_protocol {
encoder.u8(0x09)?; // pinProtocol
encoder.u8(*pin_protocol)?;
}
Ok(())
}
}
#[derive(Debug, Default)]
pub struct MakeCredentialResponse {
pub format: String,
pub auth_data: AuthenticatorData,
}
impl MakeCredentialResponse {
pub fn decode<R: ReadBytesExt>(mut reader: R) -> FidoResult<Self> {
let status = reader.read_u8().context(FidoErrorKind::CborDecode)?;
if status != 0 {
Err(FidoErrorKind::CborError(CborErrorCode::from(status)))?
}
let mut decoder = Decoder::new(Config::default(), reader);
let mut response = MakeCredentialResponse::default();
for _ in 0..decoder.object()? {
let key = decoder.u8()?;
match key {
0x01 => response.format = decoder.text()?,
0x02 => response.auth_data = AuthenticatorData::from_bytes(&decoder.bytes()?)?,
0x03 => break, // TODO: parse attestation
_ => continue,
}
}
Ok(response)
}
}
#[derive(Debug, Default)]
pub struct GetAssertionRequest<'a> {
pub rp_id: &'a str,
pub client_data_hash: &'a [u8],
pub allow_list: &'a [PublicKeyCredentialDescriptor],
pub extensions: &'a [(&'a str, &'a Value)],
pub options: Option<AuthenticatorOptions>,
pub pin_auth: Option<[u8; 16]>,
pub pin_protocol: Option<u8>,
}
impl<'a> GetAssertionRequest<'a> {
pub fn encode<W: WriteBytesExt>(&self, mut encoder: &mut Encoder<W>) -> FidoResult<()> {
encoder
.writer()
.write_u8(0x02)
.context(FidoErrorKind::CborEncode)?; // authenticatorGetAssertion
let mut length = 2;
length += !self.allow_list.is_empty() as usize;
length += !self.extensions.is_empty() as usize;
length += self
.options
.as_ref()
.map(|opt| opt.encoded())
.unwrap_or(false) as usize;
length += self.pin_auth.is_some() as usize;
length += self.pin_protocol.is_some() as usize;
encoder.object(length)?;
encoder.u8(0x01)?; // rpId
encoder.text(&self.rp_id)?;
encoder.u8(0x02)?; // clientDataHash
encoder.bytes(self.client_data_hash)?;
if !self.allow_list.is_empty() {
encoder.u8(0x03)?; // allowList
encoder.array(self.allow_list.len())?;
for item in self.allow_list {
item.encode(&mut encoder)?;
}
}
if self.extensions.len() > 0 {
encoder.u8(0x04)?; // extensions
encoder.object(self.extensions.len())?;
for (key, value) in self.extensions {
encoder.text(key)?;
let mut generic = GenericEncoder::new(encoder.writer());
generic.value(value)?;
}
}
if let Some(options) = &self.options {
if options.encoded() {
encoder.u8(0x05)?; // options
options.encode(&mut encoder)?;
}
}
if let Some(pin_auth) = &self.pin_auth {
encoder.u8(0x06)?; // pinAuth
encoder.bytes(pin_auth)?;
}
if let Some(pin_protocol) = &self.pin_protocol {
encoder.u8(0x07)?; // pinProtocol
encoder.u8(*pin_protocol)?;
}
Ok(())
}
}
#[derive(Debug, Default)]
pub struct GetAssertionResponse {
pub credential: Option<PublicKeyCredentialDescriptor>,
pub auth_data_bytes: Vec<u8>,
pub auth_data: AuthenticatorData,
pub signature: Vec<u8>,
}
impl GetAssertionResponse {
pub fn decode<R: ReadBytesExt>(mut reader: R) -> FidoResult<Self> {
let status = reader.read_u8().context(FidoErrorKind::CborDecode)?;
if status != 0 {
Err(FidoErrorKind::CborError(CborErrorCode::from(status)))?
}
let mut decoder = Decoder::new(Config::default(), reader);
let mut response = GetAssertionResponse::default();
for _ in 0..decoder.object()? {
let key = decoder.u8()?;
match key {
0x01 => {
response.credential = Some(PublicKeyCredentialDescriptor::decode(&mut decoder)?)
}
0x02 => {
response.auth_data_bytes = decoder.bytes()?;
response.auth_data = AuthenticatorData::from_bytes(&response.auth_data_bytes)?;
}
0x03 => response.signature = decoder.bytes()?,
_ => continue,
}
}
Ok(response)
}
}
#[derive(Debug, Default)]
pub struct GetInfoResponse {
pub versions: Vec<String>,
pub extensions: Vec<String>,
pub aaguid: [u8; 16],
pub options: OptionsInfo,
pub max_msg_size: u16,
pub pin_protocols: Vec<u8>,
pub max_credential_count_in_list: Option<u32>,
pub max_credential_id_len: Option<u32>,
pub transports: Vec<String>,
pub algorithms: Vec<CoseKey>,
pub max_authenticator_config_len: Option<u32>,
pub default_cred_protect: Option<u8>,
}
impl GetInfoResponse {
pub fn decode<R: ReadBytesExt>(mut reader: R) -> FidoResult<Self> {
let status = reader.read_u8().context(FidoErrorKind::CborDecode)?;
if status != 0 {
Err(FidoErrorKind::CborError(CborErrorCode::from(status)))?
}
let mut generic = GenericDecoder::new(Config::default(), reader);
let mut response = GetInfoResponse::default();
for _ in 0..generic.borrow_mut().object()? {
match generic.borrow_mut().u8()? {
0x01 => {
let decoder = generic.borrow_mut();
for _ in 0..decoder.array()? {
response.versions.push(decoder.text()?);
}
}
0x02 => {
let decoder = generic.borrow_mut();
for _ in 0..decoder.array()? {
response.extensions.push(decoder.text()?);
}
}
0x03 => response
.aaguid
.copy_from_slice(&generic.borrow_mut().bytes()?[..]),
0x04 => response.options = OptionsInfo::decode(&mut generic.borrow_mut())?,
0x05 => response.max_msg_size = generic.borrow_mut().u16()?,
0x06 => {
let decoder = generic.borrow_mut();
for _ in 0..decoder.array()? {
response.pin_protocols.push(decoder.u8()?);
}
}
0x07 => response.max_credential_count_in_list = Some(generic.borrow_mut().u32()?),
0x08 => response.max_credential_id_len = Some(generic.borrow_mut().u32()?),
0x09 => {
let decoder = generic.borrow_mut();
for _ in 0..decoder.array()? {
response.transports.push(decoder.text()?);
}
}
0x0A => {
for _ in 0..generic.borrow_mut().array()? {
response.algorithms.push(CoseKey::decode(&mut generic)?);
}
}
0x0B => response.max_authenticator_config_len = Some(generic.borrow_mut().u32()?),
0x0C => response.default_cred_protect = Some(generic.borrow_mut().u8()?),
_ => continue,
}
}
Ok(response)
}
}
#[derive(Debug, Default)]
pub struct ClientPinRequest<'a> {
pub pin_protocol: u8,
pub sub_command: u8,
pub key_agreement: Option<&'a CoseKey>,
pub pin_auth: Option<[u8; 16]>,
pub new_pin_enc: Option<Vec<u8>>,
pub pin_hash_enc: Option<[u8; 16]>,
}
impl<'a> ClientPinRequest<'a> {
pub fn encode<W: WriteBytesExt>(&self, encoder: &mut Encoder<W>) -> FidoResult<()> {
encoder
.writer()
.write_u8(0x06)
.context(FidoErrorKind::CborEncode)?; // authenticatorClientPIN
let mut length = 2;
length += self.key_agreement.is_some() as usize;
length += self.pin_auth.is_some() as usize;
length += self.new_pin_enc.is_some() as usize;
length += self.pin_hash_enc.is_some() as usize;
encoder.object(length)?;
encoder.u8(0x01)?; // pinProtocol
encoder.u8(self.pin_protocol)?;
encoder.u8(0x02)?; // subCommand
encoder.u8(self.sub_command)?;
if let Some(key_agreement) = self.key_agreement {
encoder.u8(0x03)?; // keyAgreement
key_agreement.encode(encoder)?;
}
if let Some(pin_auth) = &self.pin_auth {
encoder.u8(0x04)?; // pinAuth
encoder.bytes(pin_auth)?;
}
if let Some(new_pin_enc) = &self.new_pin_enc {
encoder.u8(0x05)?; // newPinEnc
encoder.bytes(&new_pin_enc)?;
}
if let Some(pin_hash_enc) = &self.pin_hash_enc {
encoder.u8(0x06)?; // pinHashEnc
encoder.bytes(pin_hash_enc)?;
}
Ok(())
}
}
#[derive(Debug, Default)]
pub struct ClientPinResponse {
pub key_agreement: Option<CoseKey>,
pub pin_token: Option<[u8; 16]>,
pub retries: Option<u8>,
}
impl ClientPinResponse {
pub fn decode<R: ReadBytesExt>(mut reader: R) -> FidoResult<Self> {
let status = reader.read_u8().context(FidoErrorKind::CborDecode)?;
if status != 0 {
Err(FidoErrorKind::CborError(CborErrorCode::from(status)))?
}
let mut decoder = Decoder::new(Config::default(), reader);
let mut response = ClientPinResponse::default();
for _ in 0..decoder.object()? {
match decoder.u8()? {
0x01 => {
let mut generic = GenericDecoder::from_decoder(decoder);
response.key_agreement = Some(CoseKey::decode(&mut generic)?);
decoder = generic.into_inner();
}
0x02 => {
let mut pin_token = [0; 16];
pin_token.copy_from_slice(&decoder.bytes()?[..]);
response.pin_token = Some(pin_token)
}
0x03 => response.retries = Some(decoder.u8()?),
_ => continue,
}
}
Ok(response)
}
}
#[derive(Debug)]
pub struct OptionsInfo {
pub plat: bool,
pub rk: bool,
pub client_pin: Option<bool>,
pub up: bool,
pub uv: Option<bool>,
}
impl Default for OptionsInfo {
fn default() -> Self {
OptionsInfo {
plat: false,
rk: false,
client_pin: None,
up: true,
uv: None,
}
}
}
impl OptionsInfo {
pub fn decode<R: ReadBytesExt>(decoder: &mut Decoder<R>) -> FidoResult<Self> {
let mut options = OptionsInfo::default();
for _ in 0..decoder.object()? {
match decoder.text()?.as_ref() {
"plat" => options.plat = decoder.bool()?,
"rk" => options.rk = decoder.bool()?,
"clientPin" => options.client_pin = Some(decoder.bool()?),
"up" => options.up = decoder.bool()?,
"uv" => options.uv = Some(decoder.bool()?),
_ => {
decoder.bool()?;
}
}
}
Ok(options)
}
}
#[derive(Debug, Default)]
pub struct AuthenticatorData {
pub rp_id_hash: [u8; 32],
pub up: bool,
pub uv: bool,
pub sign_count: u32,
pub attested_credential_data: AttestedCredentialData,
pub extensions: HashMap<String, Value>,
}
impl AuthenticatorData {
pub fn from_bytes(bytes: &[u8]) -> FidoResult<Self> {
let mut data = AuthenticatorData::default();
data.rp_id_hash.copy_from_slice(&bytes[0..32]);
let flags = bytes[32];
data.up = (flags & 0x01) == 0x01;
data.uv = (flags & 0x02) == 0x02;
let is_attested = (flags & 0x40) == 0x40;
let has_extension_data = (flags & 0x80) == 0x80;
data.sign_count = BigEndian::read_u32(&bytes[33..37]);
if bytes.len() < 38 {
return Ok(data);
}
let mut cur = Cursor::new(&bytes[37..]);
if is_attested {
let attested_credential_data = AttestedCredentialData::from_bytes(&mut cur)?;
data.attested_credential_data = attested_credential_data;
if cur.position() >= (bytes.len() - 37) as u64 {
return Ok(data);
}
}
if has_extension_data {
let mut decoder = GenericDecoder::new(Config::default(), cur);
for _ in 0..decoder.borrow_mut().object()? {
let key = decoder.borrow_mut().text()?;
let value = decoder.value()?;
data.extensions.insert(key.to_string(), value);
}
}
Ok(data)
}
}
#[derive(Debug, Default)]
pub struct AttestedCredentialData {
pub aaguid: [u8; 16],
pub credential_id: Vec<u8>,
pub credential_public_key: CoseKey,
}
impl AttestedCredentialData {
pub fn from_bytes(cur: &mut Cursor<&[u8]>) -> FidoResult<Self> {
let mut response = AttestedCredentialData::default();
let bytes = cur.get_ref();
if bytes.is_empty() {
return Ok(response);
}
response.aaguid.copy_from_slice(&bytes[0..16]);
let id_length = BigEndian::read_u16(&bytes[16..18]) as usize;
response.credential_id = Vec::from(&bytes[18..(18 + id_length)]);
cur.set_position(18 + id_length as u64);
let mut decoder = GenericDecoder::new(Config::default(), cur);
response.credential_public_key = CoseKey::decode(&mut decoder)?;
Ok(response)
}
}
#[derive(Debug, Default)]
pub struct P256Key {
x: [u8; 32],
y: [u8; 32],
}
impl P256Key {
pub fn from_cose(cose: &CoseKey) -> FidoResult<Self> {
if cose.key_type != 2 || cose.algorithm != -7 {
Err(FidoErrorKind::KeyType)?
}
if let (
Some(Value::U8(curve)),
Some(Value::Bytes(value::Bytes::Bytes(x))),
Some(Value::Bytes(value::Bytes::Bytes(y))),
) = (
cose.parameters.get(&-1),
cose.parameters.get(&-2),
cose.parameters.get(&-3),
) {
if *curve != 1 {
Err(FidoErrorKind::KeyType)?
}
let mut key = P256Key::default();
key.x.copy_from_slice(&x);
key.y.copy_from_slice(&y);
return Ok(key);
}
Err(FidoErrorKind::KeyType)?
}
pub fn from_bytes(bytes: &[u8]) -> FidoResult<Self> {
if bytes.len() != 65 || bytes[0] != 0x04 {
Err(FidoErrorKind::CborDecode)?
}
let mut res = P256Key::default();
res.x.copy_from_slice(&bytes[1..33]);
res.y.copy_from_slice(&bytes[33..65]);
Ok(res)
}
pub fn to_cose(&self) -> CoseKey {
CoseKey {
key_type: 2,
algorithm: -7,
parameters: [
(-1, Value::U8(1)),
(-2, Value::Bytes(value::Bytes::Bytes(self.x.to_vec()))),
(-3, Value::Bytes(value::Bytes::Bytes(self.y.to_vec()))),
]
.iter()
.cloned()
.collect(),
}
}
pub fn bytes(&self) -> [u8; 65] {
let mut bytes = [0; 65];
bytes[0] = 0x04;
bytes[1..33].copy_from_slice(&self.x);
bytes[33..65].copy_from_slice(&self.y);
bytes
}
}
#[derive(Debug, Default, Clone)]
pub struct CoseKey {
key_type: u16,
algorithm: i32,
parameters: HashMap<i16, Value>,
}
impl CoseKey {
pub fn encode<W: WriteBytesExt>(&self, encoder: &mut Encoder<W>) -> FidoResult<()> {
let size = 1 + self.parameters.len();
encoder.object(size)?;
encoder.i16(0x01)?; // keyType
encoder.u16(self.key_type)?;
//encoder.i16(0x02)?; // algorithm
//encoder.i32(self.algorithm)?;
for (key, value) in self.parameters.iter() {
encoder.i16(*key)?;
let mut generic = GenericEncoder::new(encoder.writer());
generic.value(value)?;
}
Ok(())
}
pub fn decode<R: ReadBytesExt>(generic: &mut GenericDecoder<R>) -> FidoResult<Self> {
let items;
{
let decoder = generic.borrow_mut();
items = decoder.object()?;
}
let mut cose_key = CoseKey::default();
cose_key.algorithm = -7;
for _ in 0..items {
match generic.borrow_mut().i16()? {
0x01 => cose_key.key_type = generic.borrow_mut().u16()?,
0x02 => cose_key.algorithm = generic.borrow_mut().i32()?,
key if key < 0 => {
cose_key.parameters.insert(key, generic.value()?);
}
_ => {
generic.value()?; // skip unknown parameter
}
}
}
Ok(cose_key)
}
}
#[derive(Debug, Default)]
pub struct PublicKeyCredentialRpEntity<'a> {
pub id: &'a str,
pub name: Option<&'a str>,
pub icon: Option<&'a str>,
}
impl<'a> PublicKeyCredentialRpEntity<'a> {
pub fn encode<W: WriteBytesExt>(&self, encoder: &mut Encoder<W>) -> FidoResult<()> {
let mut length = 1;
length += self.name.is_some() as usize;
length += self.icon.is_some() as usize;
encoder.object(length)?;
encoder.text("id")?;
encoder.text(&self.id)?;
if let Some(icon) = &self.icon {
encoder.text("icon")?;
encoder.text(&icon)?;
}
if let Some(name) = &self.name {
encoder.text("name")?;
encoder.text(&name)?;
}
Ok(())
}
}
#[derive(Debug, Default)]
pub struct PublicKeyCredentialUserEntity<'a> {
pub id: &'a [u8],
pub name: &'a str,
pub icon: Option<&'a str>,
pub display_name: Option<&'a str>,
}
impl<'a> PublicKeyCredentialUserEntity<'a> {
pub fn encode<W: WriteBytesExt>(&self, encoder: &mut Encoder<W>) -> FidoResult<()> {
let mut length = 2;
length += self.icon.is_some() as usize;
length += self.display_name.is_some() as usize;
encoder.object(length)?;
encoder.text("id")?;
encoder.bytes(&self.id)?;
if let Some(icon) = &self.icon {
encoder.text("icon")?;
encoder.text(&icon)?;
}
encoder.text("name")?;
encoder.text(&self.name)?;
if let Some(display_name) = &self.display_name {
encoder.text("displayName")?;
encoder.text(&display_name)?;
}
Ok(())
}
}
#[derive(Debug, Default)]
pub struct PublicKeyCredentialDescriptor {
pub cred_type: String,
pub id: Vec<u8>,
}
impl PublicKeyCredentialDescriptor {
pub fn decode<R: ReadBytesExt>(decoder: &mut Decoder<R>) -> FidoResult<Self> {
let mut response = PublicKeyCredentialDescriptor::default();
for _ in 0..decoder.object()? {
match decoder.text()?.as_ref() {
"id" => response.id = decoder.bytes()?,
"type" => response.cred_type = decoder.text()?,
_ => continue,
}
}
Ok(response)
}
pub fn encode<W: WriteBytesExt>(&self, encoder: &mut Encoder<W>) -> FidoResult<()> {
encoder.object(2)?;
encoder.text("id")?;
encoder.bytes(&self.id)?;
encoder.text("type")?;
encoder.text(&self.cred_type)?;
Ok(())
}
}
#[derive(Debug)]
pub struct AuthenticatorOptions {
pub rk: bool,
pub uv: bool,
pub up: bool,
}
impl AuthenticatorOptions {
pub fn encoded(&self) -> bool {
self.rk || self.uv || self.up
}
pub fn encode<W: WriteBytesExt>(&self, encoder: &mut Encoder<W>) -> FidoResult<()> {
let length = (self.rk as usize) + (self.uv as usize) + (self.up as usize);
encoder.object(length)?;
if self.rk {
encoder.text("rk")?;
encoder.bool(true)?;
}
if self.uv {
encoder.text("uv")?;
encoder.bool(true)?;
}
if self.up {
encoder.text("up")?;
encoder.bool(true)?;
}
Ok(())
}
}