blob: f6d8108617a2fdbf3dd36af64b82c1fd71033558 [file] [log] [blame]
// Copyright 2020, The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#![allow(unused_variables)]
//! This crate implements the IKeystoreSecurityLevel interface.
use crate::{database::Uuid, gc::Gc, globals::get_keymint_device};
use android_hardware_security_keymint::aidl::android::hardware::security::keymint::{
Algorithm::Algorithm, HardwareAuthenticatorType::HardwareAuthenticatorType,
IKeyMintDevice::IKeyMintDevice, KeyCreationResult::KeyCreationResult, KeyFormat::KeyFormat,
KeyMintHardwareInfo::KeyMintHardwareInfo, KeyParameter::KeyParameter,
KeyParameterValue::KeyParameterValue, SecurityLevel::SecurityLevel, Tag::Tag,
};
use android_system_keystore2::aidl::android::system::keystore2::{
AuthenticatorSpec::AuthenticatorSpec, CreateOperationResponse::CreateOperationResponse,
Domain::Domain, IKeystoreOperation::IKeystoreOperation,
IKeystoreSecurityLevel::BnKeystoreSecurityLevel,
IKeystoreSecurityLevel::IKeystoreSecurityLevel, KeyDescriptor::KeyDescriptor,
KeyMetadata::KeyMetadata, KeyParameters::KeyParameters,
};
use crate::globals::ENFORCEMENTS;
use crate::key_parameter::KeyParameter as KsKeyParam;
use crate::key_parameter::KeyParameterValue as KsKeyParamValue;
use crate::utils::{check_key_permission, uid_to_android_user, Asp};
use crate::{
database::{CertificateInfo, KeyIdGuard},
globals::DB,
};
use crate::{
database::{DateTime, KeyMetaData, KeyMetaEntry, KeyType},
permission::KeyPerm,
};
use crate::{
database::{KeyEntry, KeyEntryLoadBits, SubComponentType},
operation::KeystoreOperation,
operation::OperationDb,
};
use crate::{
error::{self, map_km_error, map_or_log_err, Error, ErrorCode},
utils::key_characteristics_to_internal,
};
use anyhow::{anyhow, Context, Result};
use binder::{IBinder, Interface, ThreadState};
/// Implementation of the IKeystoreSecurityLevel Interface.
pub struct KeystoreSecurityLevel {
security_level: SecurityLevel,
keymint: Asp,
#[allow(dead_code)]
hw_info: KeyMintHardwareInfo,
km_uuid: Uuid,
operation_db: OperationDb,
}
// Blob of 32 zeroes used as empty masking key.
static ZERO_BLOB_32: &[u8] = &[0; 32];
impl KeystoreSecurityLevel {
/// Creates a new security level instance wrapped in a
/// BnKeystoreSecurityLevel proxy object. It also
/// calls `IBinder::set_requesting_sid` on the new interface, because
/// we need it for checking keystore permissions.
pub fn new_native_binder(
security_level: SecurityLevel,
) -> Result<(impl IKeystoreSecurityLevel + Send, Uuid)> {
let (dev, hw_info, km_uuid) = get_keymint_device(&security_level)
.context("In KeystoreSecurityLevel::new_native_binder.")?;
let result = BnKeystoreSecurityLevel::new_binder(Self {
security_level,
keymint: dev,
hw_info,
km_uuid,
operation_db: OperationDb::new(),
});
result.as_binder().set_requesting_sid(true);
Ok((result, km_uuid))
}
fn store_new_key(
&self,
key: KeyDescriptor,
creation_result: KeyCreationResult,
user_id: u32,
) -> Result<KeyMetadata> {
let KeyCreationResult {
keyBlob: key_blob,
keyCharacteristics: key_characteristics,
certificateChain: mut certificate_chain,
} = creation_result;
let mut cert_info: CertificateInfo = CertificateInfo::new(
match certificate_chain.len() {
0 => None,
_ => Some(certificate_chain.remove(0).encodedCertificate),
},
match certificate_chain.len() {
0 => None,
_ => Some(
certificate_chain
.iter()
.map(|c| c.encodedCertificate.iter())
.flatten()
.copied()
.collect(),
),
},
);
let mut key_parameters = key_characteristics_to_internal(key_characteristics);
key_parameters.push(KsKeyParam::new(
KsKeyParamValue::UserID(user_id as i32),
SecurityLevel::SOFTWARE,
));
let creation_date = DateTime::now().context("Trying to make creation time.")?;
let key = match key.domain {
Domain::BLOB => {
KeyDescriptor { domain: Domain::BLOB, blob: Some(key_blob), ..Default::default() }
}
_ => DB
.with::<_, Result<KeyDescriptor>>(|db| {
let mut metadata = KeyMetaData::new();
metadata.add(KeyMetaEntry::CreationDate(creation_date));
let mut db = db.borrow_mut();
let (need_gc, key_id) = db
.store_new_key(
key,
&key_parameters,
&key_blob,
&cert_info,
&metadata,
&self.km_uuid,
)
.context("In store_new_key.")?;
if need_gc {
Gc::notify_gc();
}
Ok(KeyDescriptor {
domain: Domain::KEY_ID,
nspace: key_id.id(),
..Default::default()
})
})
.context("In store_new_key.")?,
};
Ok(KeyMetadata {
key,
keySecurityLevel: self.security_level,
certificate: cert_info.take_cert(),
certificateChain: cert_info.take_cert_chain(),
authorizations: crate::utils::key_parameters_to_authorizations(key_parameters),
modificationTimeMs: creation_date.to_millis_epoch(),
})
}
fn create_operation(
&self,
key: &KeyDescriptor,
operation_parameters: &[KeyParameter],
forced: bool,
) -> Result<CreateOperationResponse> {
let caller_uid = ThreadState::get_calling_uid();
// We use `scoping_blob` to extend the life cycle of the blob loaded from the database,
// so that we can use it by reference like the blob provided by the key descriptor.
// Otherwise, we would have to clone the blob from the key descriptor.
let scoping_blob: Vec<u8>;
let (km_blob, key_properties, key_id_guard) = match key.domain {
Domain::BLOB => {
check_key_permission(KeyPerm::use_(), key, &None)
.context("In create_operation: checking use permission for Domain::BLOB.")?;
(
match &key.blob {
Some(blob) => blob,
None => {
return Err(Error::sys()).context(concat!(
"In create_operation: Key blob must be specified when",
" using Domain::BLOB."
))
}
},
None,
None,
)
}
_ => {
let (key_id_guard, mut key_entry) = DB
.with::<_, Result<(KeyIdGuard, KeyEntry)>>(|db| {
db.borrow_mut().load_key_entry(
key.clone(),
KeyType::Client,
KeyEntryLoadBits::KM,
caller_uid,
|k, av| check_key_permission(KeyPerm::use_(), k, &av),
)
})
.context("In create_operation: Failed to load key blob.")?;
scoping_blob = match key_entry.take_km_blob() {
Some(blob) => blob,
None => {
return Err(Error::sys()).context(concat!(
"In create_operation: Successfully loaded key entry,",
" but KM blob was missing."
))
}
};
(
&scoping_blob,
Some((key_id_guard.id(), key_entry.into_key_parameters())),
Some(key_id_guard),
)
}
};
let purpose = operation_parameters.iter().find(|p| p.tag == Tag::PURPOSE).map_or(
Err(Error::Km(ErrorCode::INVALID_ARGUMENT))
.context("In create_operation: No operation purpose specified."),
|kp| match kp.value {
KeyParameterValue::KeyPurpose(p) => Ok(p),
_ => Err(Error::Km(ErrorCode::INVALID_ARGUMENT))
.context("In create_operation: Malformed KeyParameter."),
},
)?;
let (immediate_hat, mut auth_info) = ENFORCEMENTS
.authorize_create(
purpose,
key_properties.as_ref(),
operation_parameters.as_ref(),
// TODO b/178222844 Replace this with the configuration returned by
// KeyMintDevice::getHardwareInfo.
// For now we assume that strongbox implementations need secure timestamps.
self.security_level == SecurityLevel::STRONGBOX,
)
.context("In create_operation.")?;
let immediate_hat = immediate_hat.unwrap_or_default();
let km_dev: Box<dyn IKeyMintDevice> = self
.keymint
.get_interface()
.context("In create_operation: Failed to get KeyMint device")?;
let (begin_result, upgraded_blob) = self
.upgrade_keyblob_if_required_with(
&*km_dev,
key_id_guard,
&km_blob,
&operation_parameters,
|blob| loop {
match map_km_error(km_dev.begin(
purpose,
blob,
&operation_parameters,
&immediate_hat,
)) {
Err(Error::Km(ErrorCode::TOO_MANY_OPERATIONS)) => {
self.operation_db.prune(caller_uid)?;
continue;
}
v => return v,
}
},
)
.context("In create_operation: Failed to begin operation.")?;
let operation_challenge = auth_info.finalize_create_authorization(begin_result.challenge);
let operation = match begin_result.operation {
Some(km_op) => {
self.operation_db.create_operation(km_op, caller_uid, auth_info)
},
None => return Err(Error::sys()).context("In create_operation: Begin operation returned successfully, but did not return a valid operation."),
};
let op_binder: Box<dyn IKeystoreOperation> =
KeystoreOperation::new_native_binder(operation)
.as_binder()
.into_interface()
.context("In create_operation: Failed to create IKeystoreOperation.")?;
Ok(CreateOperationResponse {
iOperation: Some(op_binder),
operationChallenge: operation_challenge,
parameters: match begin_result.params.len() {
0 => None,
_ => Some(KeyParameters { keyParameter: begin_result.params }),
},
})
}
fn add_attestation_parameters(uid: u32, params: &[KeyParameter]) -> Result<Vec<KeyParameter>> {
let mut result = params.to_vec();
if params.iter().any(|kp| kp.tag == Tag::ATTESTATION_CHALLENGE) {
let aaid = keystore2_aaid::get_aaid(uid).map_err(|e| {
anyhow!(format!("In add_attestation_parameters: get_aaid returned status {}.", e))
})?;
result.push(KeyParameter {
tag: Tag::ATTESTATION_APPLICATION_ID,
value: KeyParameterValue::Blob(aaid),
});
}
Ok(result)
}
fn generate_key(
&self,
key: &KeyDescriptor,
attestation_key: Option<&KeyDescriptor>,
params: &[KeyParameter],
flags: i32,
entropy: &[u8],
) -> Result<KeyMetadata> {
if key.domain != Domain::BLOB && key.alias.is_none() {
return Err(error::Error::Km(ErrorCode::INVALID_ARGUMENT))
.context("In generate_key: Alias must be specified");
}
let caller_uid = ThreadState::get_calling_uid();
let key = match key.domain {
Domain::APP => KeyDescriptor {
domain: key.domain,
nspace: caller_uid as i64,
alias: key.alias.clone(),
blob: None,
},
_ => key.clone(),
};
// generate_key requires the rebind permission.
check_key_permission(KeyPerm::rebind(), &key, &None).context("In generate_key.")?;
let params = Self::add_attestation_parameters(caller_uid, params)
.context("In generate_key: Trying to get aaid.")?;
let km_dev: Box<dyn IKeyMintDevice> = self.keymint.get_interface()?;
map_km_error(km_dev.addRngEntropy(entropy))
.context("In generate_key: Trying to add entropy.")?;
let creation_result = map_km_error(km_dev.generateKey(&params))
.context("In generate_key: While generating Key")?;
let user_id = uid_to_android_user(caller_uid);
self.store_new_key(key, creation_result, user_id).context("In generate_key.")
}
fn import_key(
&self,
key: &KeyDescriptor,
attestation_key: Option<&KeyDescriptor>,
params: &[KeyParameter],
flags: i32,
key_data: &[u8],
) -> Result<KeyMetadata> {
if key.domain != Domain::BLOB && key.alias.is_none() {
return Err(error::Error::Km(ErrorCode::INVALID_ARGUMENT))
.context("In import_key: Alias must be specified");
}
let caller_uid = ThreadState::get_calling_uid();
let key = match key.domain {
Domain::APP => KeyDescriptor {
domain: key.domain,
nspace: caller_uid as i64,
alias: key.alias.clone(),
blob: None,
},
_ => key.clone(),
};
// import_key requires the rebind permission.
check_key_permission(KeyPerm::rebind(), &key, &None).context("In import_key.")?;
let params = Self::add_attestation_parameters(caller_uid, params)
.context("In import_key: Trying to get aaid.")?;
let format = params
.iter()
.find(|p| p.tag == Tag::ALGORITHM)
.ok_or(error::Error::Km(ErrorCode::INVALID_ARGUMENT))
.context("No KeyParameter 'Algorithm'.")
.and_then(|p| match &p.value {
KeyParameterValue::Algorithm(Algorithm::AES)
| KeyParameterValue::Algorithm(Algorithm::HMAC)
| KeyParameterValue::Algorithm(Algorithm::TRIPLE_DES) => Ok(KeyFormat::RAW),
KeyParameterValue::Algorithm(Algorithm::RSA)
| KeyParameterValue::Algorithm(Algorithm::EC) => Ok(KeyFormat::PKCS8),
v => Err(error::Error::Km(ErrorCode::INVALID_ARGUMENT))
.context(format!("Unknown Algorithm {:?}.", v)),
})
.context("In import_key.")?;
let km_dev: Box<dyn IKeyMintDevice> =
self.keymint.get_interface().context("In import_key: Trying to get the KM device")?;
let creation_result = map_km_error(km_dev.importKey(&params, format, key_data))
.context("In import_key: Trying to call importKey")?;
let user_id = uid_to_android_user(caller_uid);
self.store_new_key(key, creation_result, user_id).context("In import_key.")
}
fn import_wrapped_key(
&self,
key: &KeyDescriptor,
wrapping_key: &KeyDescriptor,
masking_key: Option<&[u8]>,
params: &[KeyParameter],
authenticators: &[AuthenticatorSpec],
) -> Result<KeyMetadata> {
if !(key.domain == Domain::BLOB && key.alias.is_some()) {
return Err(error::Error::Km(ErrorCode::INVALID_ARGUMENT))
.context("In import_wrapped_key: Alias must be specified.");
}
if wrapping_key.domain == Domain::BLOB {
return Err(error::Error::Km(ErrorCode::INVALID_ARGUMENT)).context(
"In import_wrapped_key: Import wrapped key not supported for self managed blobs.",
);
}
let wrapped_data = match &key.blob {
Some(d) => d,
None => {
return Err(error::Error::Km(ErrorCode::INVALID_ARGUMENT)).context(
"In import_wrapped_key: Blob must be specified and hold wrapped key data.",
)
}
};
let caller_uid = ThreadState::get_calling_uid();
let key = match key.domain {
Domain::APP => KeyDescriptor {
domain: key.domain,
nspace: caller_uid as i64,
alias: key.alias.clone(),
blob: None,
},
_ => key.clone(),
};
// import_wrapped_key requires the rebind permission for the new key.
check_key_permission(KeyPerm::rebind(), &key, &None).context("In import_wrapped_key.")?;
let (wrapping_key_id_guard, wrapping_key_entry) = DB
.with(|db| {
db.borrow_mut().load_key_entry(
wrapping_key.clone(),
KeyType::Client,
KeyEntryLoadBits::KM,
caller_uid,
|k, av| check_key_permission(KeyPerm::use_(), k, &av),
)
})
.context("Failed to load wrapping key.")?;
let wrapping_key_blob = match wrapping_key_entry.km_blob() {
Some(blob) => blob,
None => {
return Err(error::Error::sys()).context(concat!(
"No km_blob after successfully loading key.",
" This should never happen."
))
}
};
// km_dev.importWrappedKey does not return a certificate chain.
// TODO Do we assume that all wrapped keys are symmetric?
// let certificate_chain: Vec<KmCertificate> = Default::default();
let pw_sid = authenticators
.iter()
.find_map(|a| match a.authenticatorType {
HardwareAuthenticatorType::PASSWORD => Some(a.authenticatorId),
_ => None,
})
.ok_or(error::Error::Km(ErrorCode::INVALID_ARGUMENT))
.context("A password authenticator SID must be specified.")?;
let fp_sid = authenticators
.iter()
.find_map(|a| match a.authenticatorType {
HardwareAuthenticatorType::FINGERPRINT => Some(a.authenticatorId),
_ => None,
})
.ok_or(error::Error::Km(ErrorCode::INVALID_ARGUMENT))
.context("A fingerprint authenticator SID must be specified.")?;
let masking_key = masking_key.unwrap_or(ZERO_BLOB_32);
let km_dev: Box<dyn IKeyMintDevice> = self.keymint.get_interface()?;
let (creation_result, _) = self
.upgrade_keyblob_if_required_with(
&*km_dev,
Some(wrapping_key_id_guard),
wrapping_key_blob,
&[],
|wrapping_blob| {
let creation_result = map_km_error(km_dev.importWrappedKey(
wrapped_data,
wrapping_key_blob,
masking_key,
&params,
pw_sid,
fp_sid,
))?;
Ok(creation_result)
},
)
.context("In import_wrapped_key.")?;
let user_id = uid_to_android_user(caller_uid);
self.store_new_key(key, creation_result, user_id)
.context("In import_wrapped_key: Trying to store the new key.")
}
fn upgrade_keyblob_if_required_with<T, F>(
&self,
km_dev: &dyn IKeyMintDevice,
key_id_guard: Option<KeyIdGuard>,
blob: &[u8],
params: &[KeyParameter],
f: F,
) -> Result<(T, Option<Vec<u8>>)>
where
F: Fn(&[u8]) -> Result<T, Error>,
{
match f(blob) {
Err(Error::Km(ErrorCode::KEY_REQUIRES_UPGRADE)) => {
let upgraded_blob = map_km_error(km_dev.upgradeKey(blob, params))
.context("In upgrade_keyblob_if_required_with: Upgrade failed.")?;
key_id_guard.map_or(Ok(()), |key_id_guard| {
DB.with(|db| {
db.borrow_mut().set_blob(
&key_id_guard,
SubComponentType::KEY_BLOB,
Some(&upgraded_blob),
)
})
.context(concat!(
"In upgrade_keyblob_if_required_with: ",
"Failed to insert upgraded blob into the database.",
))
})?;
match f(&upgraded_blob) {
Ok(v) => Ok((v, Some(upgraded_blob))),
Err(e) => Err(e).context(concat!(
"In upgrade_keyblob_if_required_with: ",
"Failed to perform operation on second try."
)),
}
}
Err(e) => {
Err(e).context("In upgrade_keyblob_if_required_with: Failed perform operation.")
}
Ok(v) => Ok((v, None)),
}
}
}
impl binder::Interface for KeystoreSecurityLevel {}
impl IKeystoreSecurityLevel for KeystoreSecurityLevel {
fn createOperation(
&self,
key: &KeyDescriptor,
operation_parameters: &[KeyParameter],
forced: bool,
) -> binder::public_api::Result<CreateOperationResponse> {
map_or_log_err(self.create_operation(key, operation_parameters, forced), Ok)
}
fn generateKey(
&self,
key: &KeyDescriptor,
attestation_key: Option<&KeyDescriptor>,
params: &[KeyParameter],
flags: i32,
entropy: &[u8],
) -> binder::public_api::Result<KeyMetadata> {
map_or_log_err(self.generate_key(key, attestation_key, params, flags, entropy), Ok)
}
fn importKey(
&self,
key: &KeyDescriptor,
attestation_key: Option<&KeyDescriptor>,
params: &[KeyParameter],
flags: i32,
key_data: &[u8],
) -> binder::public_api::Result<KeyMetadata> {
map_or_log_err(self.import_key(key, attestation_key, params, flags, key_data), Ok)
}
fn importWrappedKey(
&self,
key: &KeyDescriptor,
wrapping_key: &KeyDescriptor,
masking_key: Option<&[u8]>,
params: &[KeyParameter],
authenticators: &[AuthenticatorSpec],
) -> binder::public_api::Result<KeyMetadata> {
map_or_log_err(
self.import_wrapped_key(key, wrapping_key, masking_key, params, authenticators),
Ok,
)
}
}