james/yubikey.rs
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Adds support for metadata command (#371)

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On firmware 5.4.3, yubikey introduced a metadata command. This returns
the policy attached to as slot as well as the public key of the pair in
the slot.

https://docs.yubico.com/yesdk/users-manual/application-piv/apdu/metadata.html
This commit is contained in:
Arthur Gautier
2022-11-12 19:12:10 +00:00
committed by GitHub
parent 7866d8d53e
commit 87ed7b2338
4 changed files with 483 additions and 104 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/apdu.rs
+5
View File
@@ -195,6 +195,9 @@ pub enum Ins {
/// Get device serial
GetSerial,
/// Get slot metadata
GetMetadata,
/// Other/unrecognized instruction codes
Other(u8),
}
@@ -219,6 +222,7 @@ impl Ins {
Ins::SetPinRetries => 0xfa,
Ins::Attest => 0xf9,
Ins::GetSerial => 0xf8,
Ins::GetMetadata => 0xf7,
Ins::Other(code) => code,
}
}
@@ -243,6 +247,7 @@ impl From<u8> for Ins {
0xfa => Ins::SetPinRetries,
0xf9 => Ins::Attest,
0xf8 => Ins::GetSerial,
0xf7 => Ins::GetMetadata,
code => Ins::Other(code),
}
}
src/piv.rs
+398 -99
View File
@@ -45,6 +45,7 @@
use crate::{
apdu::{Ins, StatusWords},
certificate::{self, Certificate, PublicKeyInfo},
consts::CB_OBJ_MAX,
error::{Error, Result},
policy::{PinPolicy, TouchPolicy},
serialization::*,
@@ -64,7 +65,6 @@ use std::{
#[cfg(feature = "untested")]
use {
crate::consts::CB_OBJ_MAX,
num_bigint_dig::traits::ModInverse,
num_integer::Integer,
num_traits::{FromPrimitive, One},
@@ -126,6 +126,9 @@ pub enum SlotId {
/// attestation of other keys generated on device with instruction `f9`. This slot is
/// not cleared on reset, but can be overwritten.
Attestation,
/// Thse slots are used for management. PIN PUK and Management Key.
Management(ManagementSlotId),
}
impl TryFrom<u8> for SlotId {
@@ -138,7 +141,9 @@ impl TryFrom<u8> for SlotId {
0x9d => Ok(SlotId::KeyManagement),
0x9e => Ok(SlotId::CardAuthentication),
0xf9 => Ok(SlotId::Attestation),
_ => RetiredSlotId::try_from(value).map(SlotId::Retired),
_ => RetiredSlotId::try_from(value)
.map(SlotId::Retired)
.or(ManagementSlotId::try_from(value).map(SlotId::Management)),
}
}
}
@@ -152,6 +157,7 @@ impl From<SlotId> for u8 {
SlotId::CardAuthentication => 0x9e,
SlotId::Retired(retired) => retired.into(),
SlotId::Attestation => 0xf9,
SlotId::Management(mgmt) => mgmt.into(),
}
}
}
@@ -159,6 +165,7 @@ impl From<SlotId> for u8 {
impl Display for SlotId {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
match self {
SlotId::Management(r) => write!(f, "{:?}", r),
SlotId::Retired(r) => write!(f, "{:?}", r),
_ => write!(f, "{:?}", self),
}
@@ -175,7 +182,10 @@ impl FromStr for SlotId {
"9d" => Ok(SlotId::KeyManagement),
"9e" => Ok(SlotId::CardAuthentication),
"f9" => Ok(SlotId::Attestation),
_ => s.parse().map(SlotId::Retired),
_ => s
.parse()
.map(SlotId::Management)
.or(s.parse().map(SlotId::Retired)),
}
}
}
@@ -189,6 +199,7 @@ impl SlotId {
SlotId::KeyManagement => 0x005f_c10b,
SlotId::CardAuthentication => 0x005f_c101,
SlotId::Retired(retired) => retired.object_id(),
SlotId::Management(mgmt) => mgmt.object_id(),
SlotId::Attestation => 0x005f_ff01,
}
}
@@ -341,8 +352,70 @@ impl RetiredSlotId {
}
}
/// Management slot IDs.
#[allow(missing_docs)]
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum ManagementSlotId {
PIN,
PUK,
Management,
}
impl TryFrom<u8> for ManagementSlotId {
type Error = Error;
fn try_from(value: u8) -> Result<Self> {
match value {
0x80 => Ok(ManagementSlotId::PIN),
0x81 => Ok(ManagementSlotId::PUK),
0x9b => Ok(ManagementSlotId::Management),
_ => Err(Error::InvalidObject),
}
}
}
impl FromStr for ManagementSlotId {
type Err = Error;
fn from_str(value: &str) -> Result<Self> {
match value {
"80" => Ok(ManagementSlotId::PIN),
"81" => Ok(ManagementSlotId::PUK),
"9b" => Ok(ManagementSlotId::Management),
_ => Err(Error::InvalidObject),
}
}
}
impl From<ManagementSlotId> for u8 {
fn from(slot: ManagementSlotId) -> u8 {
match slot {
ManagementSlotId::PIN => 0x80,
ManagementSlotId::PUK => 0x81,
ManagementSlotId::Management => 0x9b,
}
}
}
impl Display for ManagementSlotId {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(f, "{:?}", self)
}
}
impl ManagementSlotId {
/// Returns the [`ObjectId`] that corresponds to a given [`ManagementSlotId`].
pub(crate) fn object_id(self) -> ObjectId {
match self {
ManagementSlotId::PIN => 0x005f_c10b, // TODO: no idea where to get those object_ids
ManagementSlotId::PUK => 0x005f_c10c, // TODO
ManagementSlotId::Management => 0x005f_c10f, // TODO
}
}
}
/// Personal Identity Verification (PIV) key slots
pub const SLOTS: [SlotId; 24] = [
pub const SLOTS: [SlotId; 27] = [
SlotId::Authentication,
SlotId::Signature,
SlotId::KeyManagement,
@@ -367,6 +440,9 @@ pub const SLOTS: [SlotId; 24] = [
SlotId::Retired(RetiredSlotId::R19),
SlotId::Retired(RetiredSlotId::R20),
SlotId::CardAuthentication,
SlotId::Management(ManagementSlotId::PIN),
SlotId::Management(ManagementSlotId::PUK),
SlotId::Management(ManagementSlotId::Management),
];
/// Algorithm identifiers
@@ -594,101 +670,8 @@ pub fn generate(
}
}
// TODO(str4d): Response is wrapped in an ASN.1 TLV:
//
// 0x7f 0x49 -> Application | Constructed | 0x49
match algorithm {
AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => {
// It appears that the inner application-specific value returned by the
// YubiKey is constructed such that RSA pubkeys can be parsed in two ways:
//
// - Use a full ASN.1 parser on the entire datastructure:
//
// RSA 1024:
// [127, 73, 129, 136, 129, 129, 128, [ 128 octets ], 130, 3, 1, 0, 1]
// | tag | len:136 |0x81| len:128 | modulus |0x82|len3| exp |
//
// RSA 2048:
// [127, 73, 130, 1, 9, 129, 130, 1, 0, [ 256 octets ], 130, 3, 1, 0, 1]
// | tag | len:265 |0x81| len:256 | modulus |0x82|len3| exp |
//
// - Skip the first 5 bytes and use crate::serialize::get_length during TLV
// parsing (which treats 128 as a single-byte definite length instead of an
// indefinite length):
//
// RSA 1024:
// [127, 73, 129, 136, 129, 129, 128, [ 128 octets ], 130, 3, 1, 0, 1]
// | |0x81|len128| modulus |0x82|len3| exp |
//
// RSA 2048:
// [127, 73, 130, 1, 9, 129, 130, 1, 0, [ 256 octets ], 130, 3, 1, 0, 1]
// | |0x81| len:256 | modulus |0x82|len3| exp |
//
// Because of the above, treat this for now as a 2-byte ASN.1 tag with a
// 3-byte length.
let data = &response.data()[5..];
let (data, modulus_tlv) = Tlv::parse(data)?;
if modulus_tlv.tag != TAG_RSA_MODULUS {
error!("Failed to parse public key structure (modulus)");
return Err(Error::ParseError);
}
let modulus = modulus_tlv.value.to_vec();
let (_, exp_tlv) = Tlv::parse(data)?;
if exp_tlv.tag != TAG_RSA_EXP {
error!("failed to parse public key structure (public exponent)");
return Err(Error::ParseError);
}
let exp = exp_tlv.value.to_vec();
Ok(PublicKeyInfo::Rsa {
algorithm,
pubkey: RsaPublicKey::new(
BigUint::from_bytes_be(&modulus),
BigUint::from_bytes_be(&exp),
)
.map_err(|_| Error::InvalidObject)?,
})
}
AlgorithmId::EccP256 | AlgorithmId::EccP384 => {
// 2-byte ASN.1 tag, 1-byte length (because all supported EC pubkey lengths
// are shorter than 128 bytes, fitting into a definite short ASN.1 length).
let data = &response.data()[3..];
let len = if let AlgorithmId::EccP256 = algorithm {
CB_ECC_POINTP256
} else {
CB_ECC_POINTP384
};
let (_, tlv) = Tlv::parse(data)?;
if tlv.tag != TAG_ECC_POINT {
error!("failed to parse public key structure");
return Err(Error::ParseError);
}
// the curve point should always be determined by the curve
if tlv.value.len() != len {
error!("unexpected length");
return Err(Error::AlgorithmError);
}
let point = tlv.value.to_vec();
match algorithm {
AlgorithmId::EccP256 => {
EcPublicKey::<NistP256>::from_bytes(point).map(PublicKeyInfo::EcP256)
}
AlgorithmId::EccP384 => {
EcPublicKey::<NistP384>::from_bytes(point).map(PublicKeyInfo::EcP384)
}
_ => return Err(Error::AlgorithmError),
}
.map_err(|_| Error::InvalidObject)
}
}
let value = &response.data()[..];
read_public_key(algorithm, value, true)
}
#[cfg(feature = "untested")]
@@ -915,3 +898,319 @@ pub fn decrypt_data(
// don't attempt to reselect in crypt operations to avoid problems with PIN_ALWAYS
txn.authenticated_command(input, algorithm, key, true)
}
/// Read metadata
pub fn metadata(yubikey: &mut YubiKey, slot: SlotId) -> Result<SlotMetadata> {
let txn = yubikey.begin_transaction()?;
let templ = [0, Ins::GetMetadata.code(), 0, slot.into()];
let response = txn.transfer_data(&templ, &[], CB_OBJ_MAX)?;
if !response.is_success() {
if response.status_words() == StatusWords::NotSupportedError {
return Err(Error::NotSupported); // Requires firmware 5.2.3
} else {
return Err(Error::GenericError);
}
}
let buf = Buffer::new(response.data().into());
SlotMetadata::try_from(buf)
}
/// Metadata from a slot
#[derive(Debug)]
pub struct SlotMetadata {
/// Algorithm / Type of key
pub algorithm: ManagementAlgorithmId,
/// PIN and touch policy
pub policy: Option<(PinPolicy, TouchPolicy)>,
/// Imported or generated key
pub origin: Option<Origin>,
/// Pub key of the key
pub public: Option<PublicKeyInfo>,
/// Whether PIN PUK and management key are default
pub default: Option<bool>,
/// Number of retries left
pub retries: Option<Retries>,
}
impl TryFrom<Buffer> for SlotMetadata {
type Error = Error;
fn try_from(buf: Buffer) -> Result<Self> {
use nom::{
combinator::{eof, map_res},
multi::fold_many1,
number::complete::u8,
};
let out = fold_many1(
|input| Tlv::parse(input).map_err(|_| nom::Err::Error(())),
|| {
Ok(SlotMetadata {
algorithm: ManagementAlgorithmId::PINPUK,
policy: None,
origin: None,
public: None,
default: None,
retries: None,
})
},
|acc: Result<SlotMetadata>, tlv| match acc {
Ok(mut metadata) => match tlv.tag {
1 => {
metadata.algorithm = ManagementAlgorithmId::try_from(tlv.value[0])?;
Ok(metadata)
}
2 => {
fn policy_parser(
i: &[u8],
) -> nom::IResult<&[u8], (PinPolicy, TouchPolicy)> {
let (i, pin) = map_res(u8, PinPolicy::try_from)(i)?;
let (i, touch) = map_res(u8, TouchPolicy::try_from)(i)?;
let (i, _) = eof(i)?;
Ok((i, (pin, touch)))
}
metadata.policy =
Some(policy_parser(tlv.value).map_err(|_| Error::ParseError)?.1);
Ok(metadata)
}
3 => {
fn origin_parser(i: &[u8]) -> nom::IResult<&[u8], Origin> {
let (i, origin) = map_res(u8, Origin::try_from)(i)?;
let (i, _) = eof(i)?;
Ok((i, origin))
}
metadata.origin =
Some(origin_parser(tlv.value).map_err(|_| Error::ParseError)?.1);
Ok(metadata)
}
4 => {
match metadata.algorithm {
ManagementAlgorithmId::Asymetric(alg) => {
metadata.public = Some(read_public_key(alg, tlv.value, false)?);
}
_ => Err(Error::ParseError)?,
}
Ok(metadata)
}
5 => {
fn default_parser(i: &[u8]) -> nom::IResult<&[u8], bool> {
let (i, default) = u8(i)?;
let (i, _) = eof(i)?;
Ok((i, default == 1))
}
metadata.default =
Some(default_parser(tlv.value).map_err(|_| Error::ParseError)?.1);
Ok(metadata)
}
6 => {
fn retries_parser(i: &[u8]) -> nom::IResult<&[u8], Retries> {
let (i, retry_count) = u8(i)?;
let (i, remaining_count) = u8(i)?;
let (i, _) = eof(i)?;
Ok((
i,
Retries {
retry_count,
remaining_count,
},
))
}
metadata.retries =
Some(retries_parser(tlv.value).map_err(|_| Error::ParseError)?.1);
Ok(metadata)
}
_unsupported => {
// New unsupported tags
// https://docs.yubico.com/yesdk/users-manual/application-piv/apdu/metadata.html
Ok(metadata)
}
},
err => err,
},
)(buf.as_ref());
match out {
Ok((_, res)) => res,
_ => Err(Error::ParseError),
}
}
}
/// The number of retries used and remaining.
#[derive(Debug, PartialEq, Eq)]
pub struct Retries {
/// TODO
pub retry_count: u8,
/// Remaining attempts
pub remaining_count: u8,
}
/// Origin of a slot
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum Origin {
/// The key has been imported
Imported,
/// The key has been generated on the YubiKey
Generated,
}
impl TryFrom<u8> for Origin {
type Error = Error;
fn try_from(value: u8) -> Result<Self> {
match value {
1 => Ok(Origin::Generated),
2 => Ok(Origin::Imported),
_ => Err(Error::GenericError),
}
}
}
fn read_public_key(
algorithm: AlgorithmId,
input: &[u8],
skip_asn1_tag: bool,
) -> Result<PublicKeyInfo> {
// TODO(str4d): Response is wrapped in an ASN.1 TLV:
//
// 0x7f 0x49 -> Application | Constructed | 0x49
match algorithm {
AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => {
// It appears that the inner application-specific value returned by the
// YubiKey is constructed such that RSA pubkeys can be parsed in two ways:
//
// - Use a full ASN.1 parser on the entire datastructure:
//
// RSA 1024:
// [127, 73, 129, 136, 129, 129, 128, [ 128 octets ], 130, 3, 1, 0, 1]
// | tag | len:136 |0x81| len:128 | modulus |0x82|len3| exp |
//
// RSA 2048:
// [127, 73, 130, 1, 9, 129, 130, 1, 0, [ 256 octets ], 130, 3, 1, 0, 1]
// | tag | len:265 |0x81| len:256 | modulus |0x82|len3| exp |
//
// - Skip the first 5 bytes and use crate::serialize::get_length during TLV
// parsing (which treats 128 as a single-byte definite length instead of an
// indefinite length):
//
// RSA 1024:
// [127, 73, 129, 136, 129, 129, 128, [ 128 octets ], 130, 3, 1, 0, 1]
// | |0x81|len128| modulus |0x82|len3| exp |
//
// RSA 2048:
// [127, 73, 130, 1, 9, 129, 130, 1, 0, [ 256 octets ], 130, 3, 1, 0, 1]
// | |0x81| len:256 | modulus |0x82|len3| exp |
//
// Because of the above, treat this for now as a 2-byte ASN.1 tag with a
// 3-byte length.
let data = if skip_asn1_tag { &input[5..] } else { input };
let (data, modulus_tlv) = Tlv::parse(data)?;
if modulus_tlv.tag != TAG_RSA_MODULUS {
error!("Failed to parse public key structure (modulus)");
return Err(Error::ParseError);
}
let modulus = modulus_tlv.value.to_vec();
let (_, exp_tlv) = Tlv::parse(data)?;
if exp_tlv.tag != TAG_RSA_EXP {
error!("failed to parse public key structure (public exponent)");
return Err(Error::ParseError);
}
let exp = exp_tlv.value.to_vec();
Ok(PublicKeyInfo::Rsa {
algorithm,
pubkey: RsaPublicKey::new(
BigUint::from_bytes_be(&modulus),
BigUint::from_bytes_be(&exp),
)
.map_err(|_| Error::InvalidObject)?,
})
}
AlgorithmId::EccP256 | AlgorithmId::EccP384 => {
// 2-byte ASN.1 tag, 1-byte length (because all supported EC pubkey lengths
// are shorter than 128 bytes, fitting into a definite short ASN.1 length).
let data = if skip_asn1_tag { &input[3..] } else { input };
let len = if let AlgorithmId::EccP256 = algorithm {
CB_ECC_POINTP256
} else {
CB_ECC_POINTP384
};
let (_, tlv) = Tlv::parse(data)?;
if tlv.tag != TAG_ECC_POINT {
error!("failed to parse public key structure");
return Err(Error::ParseError);
}
// the curve point should always be determined by the curve
if tlv.value.len() != len {
error!("unexpected length");
return Err(Error::AlgorithmError);
}
let point = tlv.value.to_vec();
match algorithm {
AlgorithmId::EccP256 => {
EcPublicKey::<NistP256>::from_bytes(point).map(PublicKeyInfo::EcP256)
}
AlgorithmId::EccP384 => {
EcPublicKey::<NistP384>::from_bytes(point).map(PublicKeyInfo::EcP384)
}
_ => return Err(Error::AlgorithmError),
}
.map_err(|_| Error::InvalidObject)
}
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
/// Algorithms as reported by the metadata command.
pub enum ManagementAlgorithmId {
/// Used on PIN and PUK slots.
PINPUK,
/// Used on the key management slot.
ThreeDES,
/// Used on all other slots.
Asymetric(AlgorithmId),
}
impl TryFrom<u8> for ManagementAlgorithmId {
type Error = Error;
fn try_from(value: u8) -> Result<Self> {
match value {
0xff => Ok(ManagementAlgorithmId::PINPUK),
0x03 => Ok(ManagementAlgorithmId::ThreeDES),
oth => AlgorithmId::try_from(oth).map(ManagementAlgorithmId::Asymetric),
}
}
}
impl From<ManagementAlgorithmId> for u8 {
fn from(id: ManagementAlgorithmId) -> u8 {
match id {
ManagementAlgorithmId::PINPUK => 0xff,
ManagementAlgorithmId::ThreeDES => 0x03,
ManagementAlgorithmId::Asymetric(oth) => oth.into(),
}
}
}
src/policy.rs
+29 -1
View File
@@ -1,6 +1,6 @@
//! Enums representing key policies.
use crate::{serialization::Tlv, Result};
use crate::{serialization::Tlv, Error, Result};
/// Specifies how often the PIN needs to be entered for access to the credential in a
/// given slot.
@@ -35,6 +35,20 @@ impl From<PinPolicy> for u8 {
}
}
impl TryFrom<u8> for PinPolicy {
type Error = Error;
fn try_from(value: u8) -> Result<Self> {
match value {
0 => Ok(PinPolicy::Default),
1 => Ok(PinPolicy::Never),
2 => Ok(PinPolicy::Once),
3 => Ok(PinPolicy::Always),
_ => Err(Error::GenericError),
}
}
}
impl PinPolicy {
/// Writes the `PinPolicy` in the format the YubiKey expects during key generation or
/// importation.
@@ -90,3 +104,17 @@ impl TouchPolicy {
}
}
}
impl TryFrom<u8> for TouchPolicy {
type Error = Error;
fn try_from(value: u8) -> Result<Self> {
match value {
0 => Ok(TouchPolicy::Default),
1 => Ok(TouchPolicy::Never),
2 => Ok(TouchPolicy::Always),
3 => Ok(TouchPolicy::Cached),
_ => Err(Error::GenericError),
}
}
}