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Merge pull request #231 from kaczmarczyck/implicit-hmac-secret

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implicitly generate HMAC-secret
This commit is contained in:
kaczmarczyck
2020-12-09 21:19:46 +01:00
committed by GitHub
parent 74a184372e d942f0173f
commit 829fcb1238
5 changed files with 112 additions and 182 deletions
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53
src/ctap/ctap1.rs
View File

@@ -291,7 +291,7 @@ impl Ctap1Command {
let sk = crypto::ecdsa::SecKey::gensk(ctap_state.rng);
let pk = sk.genpk();
let key_handle = ctap_state
.encrypt_key_handle(sk, &application, None)
.encrypt_key_handle(sk, &application)
.map_err(|_| Ctap1StatusCode::SW_COMMAND_ABORTED)?;
if key_handle.len() > 0xFF {
// This is just being defensive with unreachable code.
@@ -386,7 +386,7 @@ impl Ctap1Command {
#[cfg(test)]
mod test {
use super::super::{key_material, CREDENTIAL_ID_BASE_SIZE, USE_SIGNATURE_COUNTER};
use super::super::{key_material, CREDENTIAL_ID_SIZE, USE_SIGNATURE_COUNTER};
use super::*;
use crypto::rng256::ThreadRng256;
use crypto::Hash256;
@@ -426,12 +426,12 @@ mod test {
0x00,
0x00,
0x00,
65 + CREDENTIAL_ID_BASE_SIZE as u8,
65 + CREDENTIAL_ID_SIZE as u8,
];
let challenge = [0x0C; 32];
message.extend(&challenge);
message.extend(application);
message.push(CREDENTIAL_ID_BASE_SIZE as u8);
message.push(CREDENTIAL_ID_SIZE as u8);
message.extend(key_handle);
message
}
@@ -471,15 +471,12 @@ mod test {
let response =
Ctap1Command::process_command(&message, &mut ctap_state, START_CLOCK_VALUE).unwrap();
assert_eq!(response[0], Ctap1Command::LEGACY_BYTE);
assert_eq!(response[66], CREDENTIAL_ID_BASE_SIZE as u8);
assert_eq!(response[66], CREDENTIAL_ID_SIZE as u8);
assert!(ctap_state
.decrypt_credential_source(
response[67..67 + CREDENTIAL_ID_BASE_SIZE].to_vec(),
&application
)
.decrypt_credential_source(response[67..67 + CREDENTIAL_ID_SIZE].to_vec(), &application)
.unwrap()
.is_some());
const CERT_START: usize = 67 + CREDENTIAL_ID_BASE_SIZE;
const CERT_START: usize = 67 + CREDENTIAL_ID_SIZE;
assert_eq!(
&response[CERT_START..CERT_START + fake_cert.len()],
&fake_cert[..]
@@ -528,9 +525,7 @@ mod test {
let rp_id = "example.com";
let application = crypto::sha256::Sha256::hash(rp_id.as_bytes());
let key_handle = ctap_state
.encrypt_key_handle(sk, &application, None)
.unwrap();
let key_handle = ctap_state.encrypt_key_handle(sk, &application).unwrap();
let message = create_authenticate_message(&application, Ctap1Flags::CheckOnly, &key_handle);
let response = Ctap1Command::process_command(&message, &mut ctap_state, START_CLOCK_VALUE);
@@ -546,9 +541,7 @@ mod test {
let rp_id = "example.com";
let application = crypto::sha256::Sha256::hash(rp_id.as_bytes());
let key_handle = ctap_state
.encrypt_key_handle(sk, &application, None)
.unwrap();
let key_handle = ctap_state.encrypt_key_handle(sk, &application).unwrap();
let application = [0x55; 32];
let message = create_authenticate_message(&application, Ctap1Flags::CheckOnly, &key_handle);
@@ -565,9 +558,7 @@ mod test {
let rp_id = "example.com";
let application = crypto::sha256::Sha256::hash(rp_id.as_bytes());
let key_handle = ctap_state
.encrypt_key_handle(sk, &application, None)
.unwrap();
let key_handle = ctap_state.encrypt_key_handle(sk, &application).unwrap();
let mut message =
create_authenticate_message(&application, Ctap1Flags::CheckOnly, &key_handle);
@@ -591,9 +582,7 @@ mod test {
let rp_id = "example.com";
let application = crypto::sha256::Sha256::hash(rp_id.as_bytes());
let key_handle = ctap_state
.encrypt_key_handle(sk, &application, None)
.unwrap();
let key_handle = ctap_state.encrypt_key_handle(sk, &application).unwrap();
let mut message =
create_authenticate_message(&application, Ctap1Flags::CheckOnly, &key_handle);
message[0] = 0xEE;
@@ -611,9 +600,7 @@ mod test {
let rp_id = "example.com";
let application = crypto::sha256::Sha256::hash(rp_id.as_bytes());
let key_handle = ctap_state
.encrypt_key_handle(sk, &application, None)
.unwrap();
let key_handle = ctap_state.encrypt_key_handle(sk, &application).unwrap();
let mut message =
create_authenticate_message(&application, Ctap1Flags::CheckOnly, &key_handle);
message[1] = 0xEE;
@@ -631,9 +618,7 @@ mod test {
let rp_id = "example.com";
let application = crypto::sha256::Sha256::hash(rp_id.as_bytes());
let key_handle = ctap_state
.encrypt_key_handle(sk, &application, None)
.unwrap();
let key_handle = ctap_state.encrypt_key_handle(sk, &application).unwrap();
let mut message =
create_authenticate_message(&application, Ctap1Flags::CheckOnly, &key_handle);
message[2] = 0xEE;
@@ -659,9 +644,7 @@ mod test {
let rp_id = "example.com";
let application = crypto::sha256::Sha256::hash(rp_id.as_bytes());
let key_handle = ctap_state
.encrypt_key_handle(sk, &application, None)
.unwrap();
let key_handle = ctap_state.encrypt_key_handle(sk, &application).unwrap();
let message =
create_authenticate_message(&application, Ctap1Flags::EnforceUpAndSign, &key_handle);
@@ -688,9 +671,7 @@ mod test {
let rp_id = "example.com";
let application = crypto::sha256::Sha256::hash(rp_id.as_bytes());
let key_handle = ctap_state
.encrypt_key_handle(sk, &application, None)
.unwrap();
let key_handle = ctap_state.encrypt_key_handle(sk, &application).unwrap();
let message = create_authenticate_message(
&application,
Ctap1Flags::DontEnforceUpAndSign,
@@ -712,7 +693,7 @@ mod test {
#[test]
fn test_process_authenticate_bad_key_handle() {
let application = [0x0A; 32];
let key_handle = vec![0x00; CREDENTIAL_ID_BASE_SIZE];
let key_handle = vec![0x00; CREDENTIAL_ID_SIZE];
let message =
create_authenticate_message(&application, Ctap1Flags::EnforceUpAndSign, &key_handle);
@@ -729,7 +710,7 @@ mod test {
#[test]
fn test_process_authenticate_without_up() {
let application = [0x0A; 32];
let key_handle = vec![0x00; CREDENTIAL_ID_BASE_SIZE];
let key_handle = vec![0x00; CREDENTIAL_ID_SIZE];
let message =
create_authenticate_message(&application, Ctap1Flags::EnforceUpAndSign, &key_handle);

20
src/ctap/data_formats.rs
View File

@@ -498,7 +498,6 @@ pub struct PublicKeyCredentialSource {
pub rp_id: String,
pub user_handle: Vec<u8>, // not optional, but nullable
pub user_display_name: Option<String>,
pub cred_random: Option<Vec<u8>>,
pub cred_protect_policy: Option<CredentialProtectionPolicy>,
pub creation_order: u64,
pub user_name: Option<String>,
@@ -513,14 +512,14 @@ enum PublicKeyCredentialSourceField {
RpId = 2,
UserHandle = 3,
UserDisplayName = 4,
CredRandom = 5,
CredProtectPolicy = 6,
CreationOrder = 7,
UserName = 8,
UserIcon = 9,
// When a field is removed, its tag should be reserved and not used for new fields. We document
// those reserved tags below.
// Reserved tags: none.
// Reserved tags:
// - CredRandom = 5,
}
impl From<PublicKeyCredentialSourceField> for cbor::KeyType {
@@ -539,7 +538,6 @@ impl From<PublicKeyCredentialSource> for cbor::Value {
PublicKeyCredentialSourceField::RpId => Some(credential.rp_id),
PublicKeyCredentialSourceField::UserHandle => Some(credential.user_handle),
PublicKeyCredentialSourceField::UserDisplayName => credential.user_display_name,
PublicKeyCredentialSourceField::CredRandom => credential.cred_random,
PublicKeyCredentialSourceField::CredProtectPolicy => credential.cred_protect_policy,
PublicKeyCredentialSourceField::CreationOrder => credential.creation_order,
PublicKeyCredentialSourceField::UserName => credential.user_name,
@@ -559,7 +557,6 @@ impl TryFrom<cbor::Value> for PublicKeyCredentialSource {
PublicKeyCredentialSourceField::RpId => rp_id,
PublicKeyCredentialSourceField::UserHandle => user_handle,
PublicKeyCredentialSourceField::UserDisplayName => user_display_name,
PublicKeyCredentialSourceField::CredRandom => cred_random,
PublicKeyCredentialSourceField::CredProtectPolicy => cred_protect_policy,
PublicKeyCredentialSourceField::CreationOrder => creation_order,
PublicKeyCredentialSourceField::UserName => user_name,
@@ -577,7 +574,6 @@ impl TryFrom<cbor::Value> for PublicKeyCredentialSource {
let rp_id = extract_text_string(ok_or_missing(rp_id)?)?;
let user_handle = extract_byte_string(ok_or_missing(user_handle)?)?;
let user_display_name = user_display_name.map(extract_text_string).transpose()?;
let cred_random = cred_random.map(extract_byte_string).transpose()?;
let cred_protect_policy = cred_protect_policy
.map(CredentialProtectionPolicy::try_from)
.transpose()?;
@@ -601,7 +597,6 @@ impl TryFrom<cbor::Value> for PublicKeyCredentialSource {
rp_id,
user_handle,
user_display_name,
cred_random,
cred_protect_policy,
creation_order,
user_name,
@@ -1373,7 +1368,6 @@ mod test {
rp_id: "example.com".to_string(),
user_handle: b"foo".to_vec(),
user_display_name: None,
cred_random: None,
cred_protect_policy: None,
creation_order: 0,
user_name: None,
@@ -1395,16 +1389,6 @@ mod test {
Ok(credential.clone())
);
let credential = PublicKeyCredentialSource {
cred_random: Some(vec![0x00; 32]),
..credential
};
assert_eq!(
PublicKeyCredentialSource::try_from(cbor::Value::from(credential.clone())),
Ok(credential.clone())
);
let credential = PublicKeyCredentialSource {
cred_protect_policy: Some(CredentialProtectionPolicy::UserVerificationOptional),
..credential

132
src/ctap/mod.rs
View File

@@ -86,10 +86,8 @@ pub const INITIAL_SIGNATURE_COUNTER: u32 = 1;
// - 16 byte initialization vector for AES-256,
// - 32 byte ECDSA private key for the credential,
// - 32 byte relying party ID hashed with SHA256,
// - (optional) 32 byte for HMAC-secret,
// - 32 byte HMAC-SHA256 over everything else.
pub const CREDENTIAL_ID_BASE_SIZE: usize = 112;
pub const CREDENTIAL_ID_MAX_SIZE: usize = CREDENTIAL_ID_BASE_SIZE + 32;
pub const CREDENTIAL_ID_SIZE: usize = 112;
// Set this bit when checking user presence.
const UP_FLAG: u8 = 0x01;
// Set this bit when checking user verification.
@@ -142,6 +140,7 @@ struct AssertionInput {
client_data_hash: Vec<u8>,
auth_data: Vec<u8>,
hmac_secret_input: Option<GetAssertionHmacSecretInput>,
has_uv: bool,
}
struct AssertionState {
@@ -231,7 +230,6 @@ where
&mut self,
private_key: crypto::ecdsa::SecKey,
application: &[u8; 32],
cred_random: Option<&[u8; 32]>,
) -> Result<Vec<u8>, Ctap2StatusCode> {
let master_keys = self.persistent_store.master_keys()?;
let aes_enc_key = crypto::aes256::EncryptionKey::new(&master_keys.encryption);
@@ -240,19 +238,14 @@ where
let mut iv = [0; 16];
iv.copy_from_slice(&self.rng.gen_uniform_u8x32()[..16]);
let block_len = if cred_random.is_some() { 6 } else { 4 };
let mut blocks = vec![[0u8; 16]; block_len];
let mut blocks = [[0u8; 16]; 4];
blocks[0].copy_from_slice(&sk_bytes[..16]);
blocks[1].copy_from_slice(&sk_bytes[16..]);
blocks[2].copy_from_slice(&application[..16]);
blocks[3].copy_from_slice(&application[16..]);
if let Some(cred_random) = cred_random {
blocks[4].copy_from_slice(&cred_random[..16]);
blocks[5].copy_from_slice(&cred_random[16..]);
}
cbc_encrypt(&aes_enc_key, iv, &mut blocks);
let mut encrypted_id = Vec::with_capacity(16 * (block_len + 3));
let mut encrypted_id = Vec::with_capacity(0x70);
encrypted_id.extend(&iv);
for b in &blocks {
encrypted_id.extend(b);
@@ -270,11 +263,9 @@ where
credential_id: Vec<u8>,
rp_id_hash: &[u8],
) -> Result<Option<PublicKeyCredentialSource>, Ctap2StatusCode> {
let has_cred_random = match credential_id.len() {
CREDENTIAL_ID_BASE_SIZE => false,
CREDENTIAL_ID_MAX_SIZE => true,
_ => return Ok(None),
};
if credential_id.len() != CREDENTIAL_ID_SIZE {
return Ok(None);
}
let master_keys = self.persistent_store.master_keys()?;
let payload_size = credential_id.len() - 32;
if !verify_hmac_256::<Sha256>(
@@ -288,9 +279,8 @@ where
let aes_dec_key = crypto::aes256::DecryptionKey::new(&aes_enc_key);
let mut iv = [0; 16];
iv.copy_from_slice(&credential_id[..16]);
let block_len = if has_cred_random { 6 } else { 4 };
let mut blocks = vec![[0u8; 16]; block_len];
for i in 0..block_len {
let mut blocks = [[0u8; 16]; 4];
for i in 0..4 {
blocks[i].copy_from_slice(&credential_id[16 * (i + 1)..16 * (i + 2)]);
}
@@ -301,15 +291,6 @@ where
decrypted_sk[16..].clone_from_slice(&blocks[1]);
decrypted_rp_id_hash[..16].clone_from_slice(&blocks[2]);
decrypted_rp_id_hash[16..].clone_from_slice(&blocks[3]);
let cred_random = if has_cred_random {
let mut decrypted_cred_random = [0; 32];
decrypted_cred_random[..16].clone_from_slice(&blocks[4]);
decrypted_cred_random[16..].clone_from_slice(&blocks[5]);
Some(decrypted_cred_random.to_vec())
} else {
None
};
if rp_id_hash != decrypted_rp_id_hash {
return Ok(None);
}
@@ -322,7 +303,6 @@ where
rp_id: String::from(""),
user_handle: vec![],
user_display_name: None,
cred_random,
cred_protect_policy: None,
creation_order: 0,
user_name: None,
@@ -464,11 +444,6 @@ where
(false, DEFAULT_CRED_PROTECT)
};
let cred_random = if use_hmac_extension {
Some(self.rng.gen_uniform_u8x32())
} else {
None
};
let has_extension_output = use_hmac_extension || cred_protect_policy.is_some();
let rp_id = rp.rp_id;
@@ -543,7 +518,6 @@ where
user_display_name: user
.user_display_name
.map(|s| truncate_to_char_boundary(&s, 64).to_string()),
cred_random: cred_random.map(|c| c.to_vec()),
cred_protect_policy,
creation_order: self.persistent_store.new_creation_order()?,
user_name: user
@@ -556,7 +530,7 @@ where
self.persistent_store.store_credential(credential_source)?;
random_id
} else {
self.encrypt_key_handle(sk.clone(), &rp_id_hash, cred_random.as_ref())?
self.encrypt_key_handle(sk.clone(), &rp_id_hash)?
};
let mut auth_data = self.generate_auth_data(&rp_id_hash, flags)?;
@@ -622,10 +596,23 @@ where
))
}
// Generates a different per-credential secret for each UV mode.
// The computation is deterministic, and private_key expected to be unique.
fn generate_cred_random(
&mut self,
private_key: &crypto::ecdsa::SecKey,
has_uv: bool,
) -> Result<[u8; 32], Ctap2StatusCode> {
let mut private_key_bytes = [0u8; 32];
private_key.to_bytes(&mut private_key_bytes);
let key = self.persistent_store.cred_random_secret(has_uv)?;
Ok(hmac_256::<Sha256>(&key, &private_key_bytes))
}
// Processes the input of a get_assertion operation for a given credential
// and returns the correct Get(Next)Assertion response.
fn assertion_response(
&self,
&mut self,
credential: PublicKeyCredentialSource,
assertion_input: AssertionInput,
number_of_credentials: Option<usize>,
@@ -634,13 +621,15 @@ where
client_data_hash,
mut auth_data,
hmac_secret_input,
has_uv,
} = assertion_input;
// Process extensions.
if let Some(hmac_secret_input) = hmac_secret_input {
let cred_random = self.generate_cred_random(&credential.private_key, has_uv)?;
let encrypted_output = self
.pin_protocol_v1
.process_hmac_secret(hmac_secret_input, &credential.cred_random)?;
.process_hmac_secret(hmac_secret_input, &cred_random)?;
let extensions_output = cbor_map! {
"hmac-secret" => encrypted_output,
};
@@ -807,6 +796,7 @@ where
client_data_hash,
auth_data: self.generate_auth_data(&rp_id_hash, flags)?,
hmac_secret_input,
has_uv,
};
let number_of_credentials = if applicable_credentials.is_empty() {
None
@@ -872,7 +862,7 @@ where
max_credential_count_in_list: MAX_CREDENTIAL_COUNT_IN_LIST.map(|c| c as u64),
// #TODO(106) update with version 2.1 of HMAC-secret
#[cfg(feature = "with_ctap2_1")]
max_credential_id_length: Some(CREDENTIAL_ID_BASE_SIZE as u64 + 32),
max_credential_id_length: Some(CREDENTIAL_ID_SIZE as u64),
#[cfg(feature = "with_ctap2_1")]
transports: Some(vec![AuthenticatorTransport::Usb]),
#[cfg(feature = "with_ctap2_1")]
@@ -1010,7 +1000,7 @@ mod test {
#[cfg(feature = "with_ctap2_1")]
expected_response.extend(
[
0x08, 0x18, 0x90, 0x09, 0x81, 0x63, 0x75, 0x73, 0x62, 0x0A, 0x81, 0xA2, 0x63, 0x61,
0x08, 0x18, 0x70, 0x09, 0x81, 0x63, 0x75, 0x73, 0x62, 0x0A, 0x81, 0xA2, 0x63, 0x61,
0x6C, 0x67, 0x26, 0x64, 0x74, 0x79, 0x70, 0x65, 0x6A, 0x70, 0x75, 0x62, 0x6C, 0x69,
0x63, 0x2D, 0x6B, 0x65, 0x79, 0x0D, 0x04,
]
@@ -1141,7 +1131,7 @@ mod test {
];
expected_auth_data.push(INITIAL_SIGNATURE_COUNTER as u8);
expected_auth_data.extend(&ctap_state.persistent_store.aaguid().unwrap());
expected_auth_data.extend(&[0x00, CREDENTIAL_ID_BASE_SIZE as u8]);
expected_auth_data.extend(&[0x00, CREDENTIAL_ID_SIZE as u8]);
assert_eq!(
auth_data[0..expected_auth_data.len()],
expected_auth_data[..]
@@ -1186,7 +1176,6 @@ mod test {
rp_id: String::from("example.com"),
user_handle: vec![],
user_display_name: None,
cred_random: None,
cred_protect_policy: None,
creation_order: 0,
user_name: None,
@@ -1291,7 +1280,7 @@ mod test {
];
expected_auth_data.push(INITIAL_SIGNATURE_COUNTER as u8);
expected_auth_data.extend(&ctap_state.persistent_store.aaguid().unwrap());
expected_auth_data.extend(&[0x00, CREDENTIAL_ID_MAX_SIZE as u8]);
expected_auth_data.extend(&[0x00, CREDENTIAL_ID_SIZE as u8]);
assert_eq!(
auth_data[0..expected_auth_data.len()],
expected_auth_data[..]
@@ -1488,8 +1477,8 @@ mod test {
let auth_data = make_credential_response.auth_data;
let offset = 37 + ctap_state.persistent_store.aaguid().unwrap().len();
assert_eq!(auth_data[offset], 0x00);
assert_eq!(auth_data[offset + 1] as usize, CREDENTIAL_ID_MAX_SIZE);
auth_data[offset + 2..offset + 2 + CREDENTIAL_ID_MAX_SIZE].to_vec()
assert_eq!(auth_data[offset + 1] as usize, CREDENTIAL_ID_SIZE);
auth_data[offset + 2..offset + 2 + CREDENTIAL_ID_SIZE].to_vec()
}
_ => panic!("Invalid response type"),
};
@@ -1604,7 +1593,6 @@ mod test {
rp_id: String::from("example.com"),
user_handle: vec![0x1D],
user_display_name: None,
cred_random: None,
cred_protect_policy: Some(
CredentialProtectionPolicy::UserVerificationOptionalWithCredentialIdList,
),
@@ -1669,7 +1657,6 @@ mod test {
rp_id: String::from("example.com"),
user_handle: vec![0x1D],
user_display_name: None,
cred_random: None,
cred_protect_policy: Some(CredentialProtectionPolicy::UserVerificationRequired),
creation_order: 0,
user_name: None,
@@ -1942,7 +1929,6 @@ mod test {
rp_id: String::from("example.com"),
user_handle: vec![],
user_display_name: None,
cred_random: None,
cred_protect_policy: None,
creation_order: 0,
user_name: None,
@@ -2013,7 +1999,7 @@ mod test {
// We are not testing the correctness of our SHA256 here, only if it is checked.
let rp_id_hash = [0x55; 32];
let encrypted_id = ctap_state
.encrypt_key_handle(private_key.clone(), &rp_id_hash, None)
.encrypt_key_handle(private_key.clone(), &rp_id_hash)
.unwrap();
let decrypted_source = ctap_state
.decrypt_credential_source(encrypted_id, &rp_id_hash)
@@ -2023,29 +2009,6 @@ mod test {
assert_eq!(private_key, decrypted_source.private_key);
}
#[test]
fn test_encrypt_decrypt_credential_with_cred_random() {
let mut rng = ThreadRng256 {};
let user_immediately_present = |_| Ok(());
let private_key = crypto::ecdsa::SecKey::gensk(&mut rng);
let mut ctap_state = CtapState::new(&mut rng, user_immediately_present, DUMMY_CLOCK_VALUE);
// Usually, the relying party ID or its hash is provided by the client.
// We are not testing the correctness of our SHA256 here, only if it is checked.
let rp_id_hash = [0x55; 32];
let cred_random = [0xC9; 32];
let encrypted_id = ctap_state
.encrypt_key_handle(private_key.clone(), &rp_id_hash, Some(&cred_random))
.unwrap();
let decrypted_source = ctap_state
.decrypt_credential_source(encrypted_id, &rp_id_hash)
.unwrap()
.unwrap();
assert_eq!(private_key, decrypted_source.private_key);
assert_eq!(Some(cred_random.to_vec()), decrypted_source.cred_random);
}
#[test]
fn test_encrypt_decrypt_bad_hmac() {
let mut rng = ThreadRng256 {};
@@ -2056,30 +2019,7 @@ mod test {
// Same as above.
let rp_id_hash = [0x55; 32];
let encrypted_id = ctap_state
.encrypt_key_handle(private_key, &rp_id_hash, None)
.unwrap();
for i in 0..encrypted_id.len() {
let mut modified_id = encrypted_id.clone();
modified_id[i] ^= 0x01;
assert!(ctap_state
.decrypt_credential_source(modified_id, &rp_id_hash)
.unwrap()
.is_none());
}
}
#[test]
fn test_encrypt_decrypt_bad_hmac_with_cred_random() {
let mut rng = ThreadRng256 {};
let user_immediately_present = |_| Ok(());
let private_key = crypto::ecdsa::SecKey::gensk(&mut rng);
let mut ctap_state = CtapState::new(&mut rng, user_immediately_present, DUMMY_CLOCK_VALUE);
// Same as above.
let rp_id_hash = [0x55; 32];
let cred_random = [0xC9; 32];
let encrypted_id = ctap_state
.encrypt_key_handle(private_key, &rp_id_hash, Some(&cred_random))
.encrypt_key_handle(private_key, &rp_id_hash)
.unwrap();
for i in 0..encrypted_id.len() {
let mut modified_id = encrypted_id.clone();

30
src/ctap/pin_protocol_v1.rs
View File

@@ -56,23 +56,16 @@ fn verify_pin_auth(hmac_key: &[u8], hmac_contents: &[u8], pin_auth: &[u8]) -> bo
fn encrypt_hmac_secret_output(
shared_secret: &[u8; 32],
salt_enc: &[u8],
cred_random: &[u8],
cred_random: &[u8; 32],
) -> Result<Vec<u8>, Ctap2StatusCode> {
if salt_enc.len() != 32 && salt_enc.len() != 64 {
return Err(Ctap2StatusCode::CTAP2_ERR_UNSUPPORTED_EXTENSION);
}
if cred_random.len() != 32 {
// We are strict here. We need at least 32 byte, but expect exactly 32.
return Err(Ctap2StatusCode::CTAP2_ERR_UNSUPPORTED_EXTENSION);
}
let aes_enc_key = crypto::aes256::EncryptionKey::new(shared_secret);
let aes_dec_key = crypto::aes256::DecryptionKey::new(&aes_enc_key);
// The specification specifically asks for a zero IV.
let iv = [0u8; 16];
let mut cred_random_secret = [0u8; 32];
cred_random_secret.copy_from_slice(cred_random);
// With the if clause restriction above, block_len can only be 2 or 4.
let block_len = salt_enc.len() / 16;
let mut blocks = vec![[0u8; 16]; block_len];
@@ -84,7 +77,7 @@ fn encrypt_hmac_secret_output(
let mut decrypted_salt1 = [0u8; 32];
decrypted_salt1[..16].copy_from_slice(&blocks[0]);
decrypted_salt1[16..].copy_from_slice(&blocks[1]);
let output1 = hmac_256::<Sha256>(&cred_random_secret, &decrypted_salt1[..]);
let output1 = hmac_256::<Sha256>(&cred_random[..], &decrypted_salt1[..]);
for i in 0..2 {
blocks[i].copy_from_slice(&output1[16 * i..16 * (i + 1)]);
}
@@ -93,7 +86,7 @@ fn encrypt_hmac_secret_output(
let mut decrypted_salt2 = [0u8; 32];
decrypted_salt2[..16].copy_from_slice(&blocks[2]);
decrypted_salt2[16..].copy_from_slice(&blocks[3]);
let output2 = hmac_256::<Sha256>(&cred_random_secret, &decrypted_salt2[..]);
let output2 = hmac_256::<Sha256>(&cred_random[..], &decrypted_salt2[..]);
for i in 0..2 {
blocks[i + 2].copy_from_slice(&output2[16 * i..16 * (i + 1)]);
}
@@ -588,7 +581,7 @@ impl PinProtocolV1 {
pub fn process_hmac_secret(
&self,
hmac_secret_input: GetAssertionHmacSecretInput,
cred_random: &Option<Vec<u8>>,
cred_random: &[u8; 32],
) -> Result<Vec<u8>, Ctap2StatusCode> {
let GetAssertionHmacSecretInput {
key_agreement,
@@ -602,12 +595,7 @@ impl PinProtocolV1 {
// Hard to tell what the correct error code here is.
return Err(Ctap2StatusCode::CTAP2_ERR_UNSUPPORTED_EXTENSION);
}
match cred_random {
Some(cr) => encrypt_hmac_secret_output(&shared_secret, &salt_enc[..], cr),
// This is the case if the credential was not created with HMAC-secret.
None => Err(Ctap2StatusCode::CTAP2_ERR_UNSUPPORTED_EXTENSION),
}
encrypt_hmac_secret_output(&shared_secret, &salt_enc[..], cred_random)
}
#[cfg(feature = "with_ctap2_1")]
@@ -1195,14 +1183,6 @@ mod test {
let output = encrypt_hmac_secret_output(&shared_secret, &salt_enc, &cred_random);
assert_eq!(output.unwrap().len(), 64);
let salt_enc = [0x5E; 32];
let cred_random = [0xC9; 33];
let output = encrypt_hmac_secret_output(&shared_secret, &salt_enc, &cred_random);
assert_eq!(
output,
Err(Ctap2StatusCode::CTAP2_ERR_UNSUPPORTED_EXTENSION)
);
let mut salt_enc = [0x00; 32];
let cred_random = [0xC9; 32];

59
src/ctap/storage.rs
View File

@@ -72,9 +72,10 @@ const AAGUID: usize = 7;
const MIN_PIN_LENGTH: usize = 8;
#[cfg(feature = "with_ctap2_1")]
const MIN_PIN_LENGTH_RP_IDS: usize = 9;
const CRED_RANDOM_SECRET: usize = 10;
// Different NUM_TAGS depending on the CTAP version make the storage incompatible,
// so we use the maximum.
const NUM_TAGS: usize = 10;
const NUM_TAGS: usize = 11;
const MAX_PIN_RETRIES: u8 = 8;
#[cfg(feature = "with_ctap2_1")]
@@ -108,6 +109,7 @@ enum Key {
MinPinLength,
#[cfg(feature = "with_ctap2_1")]
MinPinLengthRpIds,
CredRandomSecret,
}
pub struct MasterKeys {
@@ -166,6 +168,7 @@ impl StoreConfig for Config {
MIN_PIN_LENGTH => add(Key::MinPinLength),
#[cfg(feature = "with_ctap2_1")]
MIN_PIN_LENGTH_RP_IDS => add(Key::MinPinLengthRpIds),
CRED_RANDOM_SECRET => add(Key::CredRandomSecret),
_ => debug_assert!(false),
}
}
@@ -230,6 +233,22 @@ impl PersistentStore {
})
.unwrap();
}
if self.store.find_one(&Key::CredRandomSecret).is_none() {
let cred_random_with_uv = rng.gen_uniform_u8x32();
let cred_random_without_uv = rng.gen_uniform_u8x32();
let mut cred_random = Vec::with_capacity(64);
cred_random.extend_from_slice(&cred_random_without_uv);
cred_random.extend_from_slice(&cred_random_with_uv);
self.store
.insert(StoreEntry {
tag: CRED_RANDOM_SECRET,
data: &cred_random,
sensitive: true,
})
.unwrap();
}
// TODO(jmichel): remove this when vendor command is in place
#[cfg(not(test))]
self.load_attestation_data_from_firmware();
@@ -411,6 +430,15 @@ impl PersistentStore {
})
}
pub fn cred_random_secret(&self, has_uv: bool) -> Result<[u8; 32], Ctap2StatusCode> {
let (_, entry) = self.store.find_one(&Key::CredRandomSecret).unwrap();
if entry.data.len() != 64 {
return Err(Ctap2StatusCode::CTAP2_ERR_VENDOR_INTERNAL_ERROR);
}
let offset = if has_uv { 32 } else { 0 };
Ok(*array_ref![entry.data, offset, 32])
}
pub fn pin_hash(&self) -> Result<Option<[u8; PIN_AUTH_LENGTH]>, Ctap2StatusCode> {
let data = match self.store.find_one(&Key::PinHash) {
None => return Ok(None),
@@ -721,7 +749,6 @@ mod test {
rp_id: String::from(rp_id),
user_handle,
user_display_name: None,
cred_random: None,
cred_protect_policy: None,
creation_order: 0,
user_name: None,
@@ -900,7 +927,6 @@ mod test {
rp_id: String::from("example.com"),
user_handle: vec![0x00],
user_display_name: None,
cred_random: None,
cred_protect_policy: Some(
CredentialProtectionPolicy::UserVerificationOptionalWithCredentialIdList,
),
@@ -946,7 +972,6 @@ mod test {
rp_id: String::from("example.com"),
user_handle: vec![0x00],
user_display_name: None,
cred_random: None,
cred_protect_policy: None,
creation_order: 0,
user_name: None,
@@ -968,7 +993,6 @@ mod test {
rp_id: String::from("example.com"),
user_handle: vec![0x00],
user_display_name: None,
cred_random: None,
cred_protect_policy: Some(CredentialProtectionPolicy::UserVerificationRequired),
creation_order: 0,
user_name: None,
@@ -987,7 +1011,7 @@ mod test {
let mut rng = ThreadRng256 {};
let mut persistent_store = PersistentStore::new(&mut rng);
// Master keys stay the same between resets.
// Master keys stay the same within the same CTAP reset cycle.
let master_keys_1 = persistent_store.master_keys().unwrap();
let master_keys_2 = persistent_store.master_keys().unwrap();
assert_eq!(master_keys_2.encryption, master_keys_1.encryption);
@@ -1003,6 +1027,28 @@ mod test {
assert!(master_keys_3.hmac != master_hmac_key.as_slice());
}
#[test]
fn test_cred_random_secret() {
let mut rng = ThreadRng256 {};
let mut persistent_store = PersistentStore::new(&mut rng);
// CredRandom secrets stay the same within the same CTAP reset cycle.
let cred_random_with_uv_1 = persistent_store.cred_random_secret(true).unwrap();
let cred_random_without_uv_1 = persistent_store.cred_random_secret(false).unwrap();
let cred_random_with_uv_2 = persistent_store.cred_random_secret(true).unwrap();
let cred_random_without_uv_2 = persistent_store.cred_random_secret(false).unwrap();
assert_eq!(cred_random_with_uv_1, cred_random_with_uv_2);
assert_eq!(cred_random_without_uv_1, cred_random_without_uv_2);
// CredRandom secrets change after reset. This test may fail if the random generator produces the
// same keys.
persistent_store.reset(&mut rng).unwrap();
let cred_random_with_uv_3 = persistent_store.cred_random_secret(true).unwrap();
let cred_random_without_uv_3 = persistent_store.cred_random_secret(false).unwrap();
assert!(cred_random_with_uv_1 != cred_random_with_uv_3);
assert!(cred_random_without_uv_1 != cred_random_without_uv_3);
}
#[test]
fn test_pin_hash() {
let mut rng = ThreadRng256 {};
@@ -1170,7 +1216,6 @@ mod test {
rp_id: String::from("example.com"),
user_handle: vec![0x00],
user_display_name: None,
cred_random: None,
cred_protect_policy: None,
creation_order: 0,
user_name: None,