| /* |
| * Copyright 2015 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. |
| */ |
| |
| #include <keymaster/contexts/soft_keymaster_context.h> |
| |
| #include <memory> |
| |
| #include <openssl/rand.h> |
| |
| #include <keymaster/android_keymaster_utils.h> |
| #include <keymaster/key_blob_utils/auth_encrypted_key_blob.h> |
| #include <keymaster/key_blob_utils/integrity_assured_key_blob.h> |
| #include <keymaster/key_blob_utils/ocb_utils.h> |
| #include <keymaster/key_blob_utils/software_keyblobs.h> |
| #include <keymaster/km_openssl/aes_key.h> |
| #include <keymaster/km_openssl/asymmetric_key.h> |
| #include <keymaster/km_openssl/attestation_utils.h> |
| #include <keymaster/km_openssl/hmac_key.h> |
| #include <keymaster/km_openssl/openssl_err.h> |
| #include <keymaster/km_openssl/triple_des_key.h> |
| #include <keymaster/legacy_support/ec_keymaster0_key.h> |
| #include <keymaster/legacy_support/ec_keymaster1_key.h> |
| #include <keymaster/legacy_support/keymaster0_engine.h> |
| #include <keymaster/legacy_support/rsa_keymaster0_key.h> |
| #include <keymaster/legacy_support/rsa_keymaster1_key.h> |
| #include <keymaster/logger.h> |
| |
| #include "soft_attestation_cert.h" |
| |
| using std::unique_ptr; |
| |
| namespace keymaster { |
| |
| namespace { |
| |
| KeymasterBlob string2Blob(const std::string& str) { |
| return KeymasterBlob(reinterpret_cast<const uint8_t*>(str.data()), str.size()); |
| } |
| |
| } // anonymous namespace |
| |
| SoftKeymasterContext::SoftKeymasterContext(const std::string& root_of_trust) |
| : rsa_factory_(new RsaKeyFactory(this)), ec_factory_(new EcKeyFactory(this)), |
| aes_factory_(new AesKeyFactory(this, this)), |
| tdes_factory_(new TripleDesKeyFactory(this, this)), |
| hmac_factory_(new HmacKeyFactory(this, this)), km1_dev_(nullptr), |
| root_of_trust_(string2Blob(root_of_trust)), os_version_(0), os_patchlevel_(0) {} |
| |
| SoftKeymasterContext::~SoftKeymasterContext() {} |
| |
| keymaster_error_t SoftKeymasterContext::SetHardwareDevice(keymaster0_device_t* keymaster0_device) { |
| if (!keymaster0_device) |
| return KM_ERROR_UNEXPECTED_NULL_POINTER; |
| |
| if ((keymaster0_device->flags & KEYMASTER_SOFTWARE_ONLY) != 0) { |
| LOG_E("SoftKeymasterContext only wraps hardware keymaster0 devices", 0); |
| return KM_ERROR_INVALID_ARGUMENT; |
| } |
| |
| km0_engine_.reset(new Keymaster0Engine(keymaster0_device)); |
| rsa_factory_.reset(new RsaKeymaster0KeyFactory(this, km0_engine_.get())); |
| ec_factory_.reset(new EcdsaKeymaster0KeyFactory(this, km0_engine_.get())); |
| // Keep AES and HMAC factories. |
| |
| return KM_ERROR_OK; |
| } |
| |
| keymaster_error_t SoftKeymasterContext::SetHardwareDevice(keymaster1_device_t* keymaster1_device) { |
| if (!keymaster1_device) |
| return KM_ERROR_UNEXPECTED_NULL_POINTER; |
| |
| km1_dev_ = keymaster1_device; |
| |
| km1_engine_.reset(new Keymaster1Engine(keymaster1_device)); |
| rsa_factory_.reset(new RsaKeymaster1KeyFactory(this, km1_engine_.get())); |
| ec_factory_.reset(new EcdsaKeymaster1KeyFactory(this, km1_engine_.get())); |
| |
| // Use default HMAC and AES key factories. Higher layers will pass HMAC/AES keys/ops that are |
| // supported by the hardware to it and other ones to the software-only factory. |
| |
| return KM_ERROR_OK; |
| } |
| |
| keymaster_error_t SoftKeymasterContext::SetSystemVersion(uint32_t os_version, |
| uint32_t os_patchlevel) { |
| os_version_ = os_version; |
| os_patchlevel_ = os_patchlevel; |
| return KM_ERROR_OK; |
| } |
| |
| void SoftKeymasterContext::GetSystemVersion(uint32_t* os_version, uint32_t* os_patchlevel) const { |
| *os_version = os_version_; |
| *os_patchlevel = os_patchlevel_; |
| } |
| |
| KeyFactory* SoftKeymasterContext::GetKeyFactory(keymaster_algorithm_t algorithm) const { |
| switch (algorithm) { |
| case KM_ALGORITHM_RSA: |
| return rsa_factory_.get(); |
| case KM_ALGORITHM_EC: |
| return ec_factory_.get(); |
| case KM_ALGORITHM_AES: |
| return aes_factory_.get(); |
| case KM_ALGORITHM_TRIPLE_DES: |
| return tdes_factory_.get(); |
| case KM_ALGORITHM_HMAC: |
| return hmac_factory_.get(); |
| default: |
| return nullptr; |
| } |
| } |
| |
| static keymaster_algorithm_t supported_algorithms[] = {KM_ALGORITHM_RSA, KM_ALGORITHM_EC, |
| KM_ALGORITHM_AES, KM_ALGORITHM_HMAC}; |
| |
| keymaster_algorithm_t* |
| SoftKeymasterContext::GetSupportedAlgorithms(size_t* algorithms_count) const { |
| *algorithms_count = array_length(supported_algorithms); |
| return supported_algorithms; |
| } |
| |
| OperationFactory* SoftKeymasterContext::GetOperationFactory(keymaster_algorithm_t algorithm, |
| keymaster_purpose_t purpose) const { |
| KeyFactory* key_factory = GetKeyFactory(algorithm); |
| if (!key_factory) |
| return nullptr; |
| return key_factory->GetOperationFactory(purpose); |
| } |
| |
| static keymaster_error_t TranslateAuthorizationSetError(AuthorizationSet::Error err) { |
| switch (err) { |
| case AuthorizationSet::OK: |
| return KM_ERROR_OK; |
| case AuthorizationSet::ALLOCATION_FAILURE: |
| return KM_ERROR_MEMORY_ALLOCATION_FAILED; |
| case AuthorizationSet::MALFORMED_DATA: |
| return KM_ERROR_UNKNOWN_ERROR; |
| } |
| return KM_ERROR_OK; |
| } |
| |
| static keymaster_error_t SetAuthorizations(const AuthorizationSet& key_description, |
| keymaster_key_origin_t origin, uint32_t os_version, |
| uint32_t os_patchlevel, AuthorizationSet* hw_enforced, |
| AuthorizationSet* sw_enforced) { |
| sw_enforced->Clear(); |
| |
| for (auto& entry : key_description) { |
| switch (entry.tag) { |
| // These cannot be specified by the client. |
| case KM_TAG_ROOT_OF_TRUST: |
| case KM_TAG_ORIGIN: |
| LOG_E("Root of trust and origin tags may not be specified", 0); |
| return KM_ERROR_INVALID_TAG; |
| |
| // These don't work. |
| case KM_TAG_ROLLBACK_RESISTANT: |
| LOG_E("KM_TAG_ROLLBACK_RESISTANT not supported", 0); |
| return KM_ERROR_UNSUPPORTED_TAG; |
| |
| // These are hidden. |
| case KM_TAG_APPLICATION_ID: |
| case KM_TAG_APPLICATION_DATA: |
| break; |
| |
| // Everything else we just copy into sw_enforced, unless the KeyFactory has placed it in |
| // hw_enforced, in which case we defer to its decision. |
| default: |
| if (hw_enforced->GetTagCount(entry.tag) == 0) |
| sw_enforced->push_back(entry); |
| break; |
| } |
| } |
| |
| sw_enforced->push_back(TAG_CREATION_DATETIME, java_time(time(NULL))); |
| sw_enforced->push_back(TAG_ORIGIN, origin); |
| sw_enforced->push_back(TAG_OS_VERSION, os_version); |
| sw_enforced->push_back(TAG_OS_PATCHLEVEL, os_patchlevel); |
| |
| return TranslateAuthorizationSetError(sw_enforced->is_valid()); |
| } |
| |
| keymaster_error_t SoftKeymasterContext::CreateKeyBlob(const AuthorizationSet& key_description, |
| const keymaster_key_origin_t origin, |
| const KeymasterKeyBlob& key_material, |
| KeymasterKeyBlob* blob, |
| AuthorizationSet* hw_enforced, |
| AuthorizationSet* sw_enforced) const { |
| keymaster_error_t error = SetAuthorizations(key_description, origin, os_version_, |
| os_patchlevel_, hw_enforced, sw_enforced); |
| if (error != KM_ERROR_OK) |
| return error; |
| |
| AuthorizationSet hidden; |
| error = BuildHiddenAuthorizations(key_description, &hidden, root_of_trust_); |
| if (error != KM_ERROR_OK) |
| return error; |
| |
| return SerializeIntegrityAssuredBlob(key_material, hidden, *hw_enforced, *sw_enforced, blob); |
| } |
| |
| keymaster_error_t SoftKeymasterContext::UpgradeKeyBlob(const KeymasterKeyBlob& key_to_upgrade, |
| const AuthorizationSet& upgrade_params, |
| KeymasterKeyBlob* upgraded_key) const { |
| UniquePtr<Key> key; |
| keymaster_error_t error = ParseKeyBlob(key_to_upgrade, upgrade_params, &key); |
| if (error != KM_ERROR_OK) |
| return error; |
| |
| // Three cases here: |
| // |
| // 1. Software key blob. Version info, if present, is in sw_enforced. If not present, we |
| // should add it. |
| // |
| // 2. Keymaster0 hardware key blob. Version info, if present, is in sw_enforced. If not |
| // present we should add it. |
| // |
| // 3. Keymaster1 hardware key blob. Version info is not present and we shouldn't have been |
| // asked to upgrade. |
| |
| // Handle case 3. |
| if (km1_dev_ && key->hw_enforced().Contains(TAG_PURPOSE) && |
| !key->hw_enforced().Contains(TAG_OS_PATCHLEVEL)) |
| return KM_ERROR_INVALID_ARGUMENT; |
| |
| // Handle case 1 and 2 |
| return UpgradeSoftKeyBlob(key, os_version_, os_patchlevel_, upgrade_params, upgraded_key); |
| } |
| |
| keymaster_error_t SoftKeymasterContext::ParseKeyBlob(const KeymasterKeyBlob& blob, |
| const AuthorizationSet& additional_params, |
| UniquePtr<Key>* key) const { |
| // This is a little bit complicated. |
| // |
| // The SoftKeymasterContext has to handle a lot of different kinds of key blobs. |
| // |
| // 1. New keymaster1 software key blobs. These are integrity-assured but not encrypted. The |
| // raw key material and auth sets should be extracted and returned. This is the kind |
| // produced by this context when the KeyFactory doesn't use keymaster0 to back the keys. |
| // |
| // 2. Old keymaster1 software key blobs. These are OCB-encrypted with an all-zero master key. |
| // They should be decrypted and the key material and auth sets extracted and returned. |
| // |
| // 3. Old keymaster0 software key blobs. These are raw key material with a small header tacked |
| // on the front. They don't have auth sets, so reasonable defaults are generated and |
| // returned along with the raw key material. |
| // |
| // 4. New keymaster0 hardware key blobs. These are integrity-assured but not encrypted (though |
| // they're protected by the keymaster0 hardware implementation). The keymaster0 key blob |
| // and auth sets should be extracted and returned. |
| // |
| // 5. Keymaster1 hardware key blobs. These are raw hardware key blobs. They contain auth |
| // sets, which we retrieve from the hardware module. |
| // |
| // 6. Old keymaster0 hardware key blobs. These are raw hardware key blobs. They don't have |
| // auth sets so reasonable defaults are generated and returned along with the key blob. |
| // |
| // Determining what kind of blob has arrived is somewhat tricky. What helps is that |
| // integrity-assured and OCB-encrypted blobs are self-consistent and effectively impossible to |
| // parse as anything else. Old keymaster0 software key blobs have a header. It's reasonably |
| // unlikely that hardware keys would have the same header. So anything that is neither |
| // integrity-assured nor OCB-encrypted and lacks the old software key header is assumed to be |
| // keymaster0 hardware. |
| |
| AuthorizationSet hw_enforced; |
| AuthorizationSet sw_enforced; |
| KeymasterKeyBlob key_material; |
| AuthorizationSet hidden; |
| keymaster_error_t error; |
| |
| auto constructKey = [&, this] () mutable -> keymaster_error_t { |
| // GetKeyFactory |
| if (error != KM_ERROR_OK) return error; |
| keymaster_algorithm_t algorithm; |
| if (!hw_enforced.GetTagValue(TAG_ALGORITHM, &algorithm) && |
| !sw_enforced.GetTagValue(TAG_ALGORITHM, &algorithm)) { |
| return KM_ERROR_INVALID_ARGUMENT; |
| } |
| auto factory = GetKeyFactory(algorithm); |
| return factory->LoadKey(move(key_material), additional_params, move(hw_enforced), |
| move(sw_enforced), key); |
| }; |
| |
| error = BuildHiddenAuthorizations(additional_params, &hidden, root_of_trust_); |
| if (error != KM_ERROR_OK) |
| return error; |
| |
| // Assume it's an integrity-assured blob (new software-only blob, or new keymaster0-backed |
| // blob). |
| error = DeserializeIntegrityAssuredBlob(blob, hidden, &key_material, &hw_enforced, &sw_enforced); |
| if (error != KM_ERROR_INVALID_KEY_BLOB) |
| return constructKey(); |
| |
| // Wasn't an integrity-assured blob. Maybe it's an OCB-encrypted blob. |
| error = ParseOcbAuthEncryptedBlob(blob, hidden, &key_material, &hw_enforced, &sw_enforced); |
| if (error == KM_ERROR_OK) |
| LOG_D("Parsed an old keymaster1 software key", 0); |
| if (error != KM_ERROR_INVALID_KEY_BLOB) |
| return constructKey(); |
| |
| // Wasn't an OCB-encrypted blob. Maybe it's an old softkeymaster blob. |
| error = ParseOldSoftkeymasterBlob(blob, &key_material, &hw_enforced, &sw_enforced); |
| if (error == KM_ERROR_OK) |
| LOG_D("Parsed an old sofkeymaster key", 0); |
| if (error != KM_ERROR_INVALID_KEY_BLOB) |
| return constructKey(); |
| |
| if (km1_dev_) { |
| error = ParseKeymaster1HwBlob(blob, additional_params, &key_material, &hw_enforced, |
| &sw_enforced); |
| } else if (km0_engine_) { |
| error = ParseKeymaster0HwBlob(blob, &key_material, &hw_enforced, &sw_enforced); |
| } else { |
| return KM_ERROR_INVALID_KEY_BLOB; |
| } |
| return constructKey(); |
| } |
| |
| keymaster_error_t SoftKeymasterContext::DeleteKey(const KeymasterKeyBlob& blob) const { |
| if (km1_engine_) { |
| // HACK. Due to a bug with Qualcomm's Keymaster implementation, which causes the device to |
| // reboot if we pass it a key blob it doesn't understand, we need to check for software |
| // keys. If it looks like a software key there's nothing to do so we just return. |
| KeymasterKeyBlob key_material; |
| AuthorizationSet hw_enforced, sw_enforced; |
| keymaster_error_t error = DeserializeIntegrityAssuredBlob_NoHmacCheck( |
| blob, &key_material, &hw_enforced, &sw_enforced); |
| if (error == KM_ERROR_OK) { |
| return KM_ERROR_OK; |
| } |
| |
| return km1_engine_->DeleteKey(blob); |
| } |
| |
| if (km0_engine_) { |
| // This could be a keymaster0 hardware key, and it could be either raw or encapsulated in an |
| // integrity-assured blob. If it's integrity-assured, we can't validate it strongly, |
| // because we don't have the necessary additional_params data. However, the probability |
| // that anything other than an integrity-assured blob would have all of the structure |
| // required to decode as a valid blob is low -- unless it's maliciously-constructed, but the |
| // deserializer should be proof against bad data, as should the keymaster0 hardware. |
| // |
| // Thus, we first try to parse it as integrity-assured. If that works, we pass the result |
| // to the underlying hardware. If not, we pass blob unmodified to the underlying hardware. |
| KeymasterKeyBlob key_material; |
| AuthorizationSet hw_enforced, sw_enforced; |
| keymaster_error_t error = DeserializeIntegrityAssuredBlob_NoHmacCheck( |
| blob, &key_material, &hw_enforced, &sw_enforced); |
| if (error == KM_ERROR_OK && km0_engine_->DeleteKey(key_material)) |
| return KM_ERROR_OK; |
| |
| km0_engine_->DeleteKey(blob); |
| |
| // We succeed unconditionally at this point, even if delete failed. Failure indicates that |
| // either the blob is a software blob (which we can't distinguish with certainty without |
| // additional_params) or because it is a hardware blob and the hardware failed. In the |
| // first case, there is no error. In the second case, the client can't do anything to fix |
| // it anyway, so it's not too harmful to simply swallow the error. This is not ideal, but |
| // it's the least-bad alternative. |
| return KM_ERROR_OK; |
| } |
| |
| // Nothing to do for software-only contexts. |
| return KM_ERROR_OK; |
| } |
| |
| keymaster_error_t SoftKeymasterContext::DeleteAllKeys() const { |
| if (km1_engine_) |
| return km1_engine_->DeleteAllKeys(); |
| |
| if (km0_engine_ && !km0_engine_->DeleteAllKeys()) |
| return KM_ERROR_UNKNOWN_ERROR; |
| |
| return KM_ERROR_OK; |
| } |
| |
| keymaster_error_t SoftKeymasterContext::AddRngEntropy(const uint8_t* buf, size_t length) const { |
| RAND_add(buf, length, 0 /* Don't assume any entropy is added to the pool. */); |
| return KM_ERROR_OK; |
| } |
| |
| keymaster_error_t SoftKeymasterContext::ParseKeymaster1HwBlob( |
| const KeymasterKeyBlob& blob, const AuthorizationSet& additional_params, |
| KeymasterKeyBlob* key_material, AuthorizationSet* hw_enforced, |
| AuthorizationSet* sw_enforced) const { |
| assert(km1_dev_); |
| |
| keymaster_blob_t client_id = {nullptr, 0}; |
| keymaster_blob_t app_data = {nullptr, 0}; |
| keymaster_blob_t* client_id_ptr = nullptr; |
| keymaster_blob_t* app_data_ptr = nullptr; |
| if (additional_params.GetTagValue(TAG_APPLICATION_ID, &client_id)) |
| client_id_ptr = &client_id; |
| if (additional_params.GetTagValue(TAG_APPLICATION_DATA, &app_data)) |
| app_data_ptr = &app_data; |
| |
| // Get key characteristics, which incidentally verifies that the HW recognizes the key. |
| keymaster_key_characteristics_t* characteristics; |
| keymaster_error_t error = km1_dev_->get_key_characteristics(km1_dev_, &blob, client_id_ptr, |
| app_data_ptr, &characteristics); |
| if (error != KM_ERROR_OK) |
| return error; |
| unique_ptr<keymaster_key_characteristics_t, Characteristics_Delete> characteristics_deleter( |
| characteristics); |
| |
| LOG_D("Module \"%s\" accepted key", km1_dev_->common.module->name); |
| |
| hw_enforced->Reinitialize(characteristics->hw_enforced); |
| sw_enforced->Reinitialize(characteristics->sw_enforced); |
| *key_material = blob; |
| return KM_ERROR_OK; |
| } |
| |
| keymaster_error_t SoftKeymasterContext::ParseKeymaster0HwBlob(const KeymasterKeyBlob& blob, |
| KeymasterKeyBlob* key_material, |
| AuthorizationSet* hw_enforced, |
| AuthorizationSet* sw_enforced) const { |
| assert(km0_engine_); |
| |
| unique_ptr<EVP_PKEY, EVP_PKEY_Delete> tmp_key(km0_engine_->GetKeymaster0PublicKey(blob)); |
| |
| if (!tmp_key) |
| return KM_ERROR_INVALID_KEY_BLOB; |
| |
| LOG_D("Module \"%s\" accepted key", km0_engine_->device()->common.module->name); |
| keymaster_error_t error = FakeKeyAuthorizations(tmp_key.get(), hw_enforced, sw_enforced); |
| if (error == KM_ERROR_OK) |
| *key_material = blob; |
| |
| return error; |
| } |
| |
| keymaster_error_t SoftKeymasterContext::GenerateAttestation(const Key& key, |
| const AuthorizationSet& attest_params, CertChainPtr* cert_chain) const { |
| |
| keymaster_error_t error = KM_ERROR_OK; |
| keymaster_algorithm_t key_algorithm; |
| if (!key.authorizations().GetTagValue(TAG_ALGORITHM, &key_algorithm)) { |
| return KM_ERROR_UNKNOWN_ERROR; |
| } |
| |
| if ((key_algorithm != KM_ALGORITHM_RSA && key_algorithm != KM_ALGORITHM_EC)) |
| return KM_ERROR_INCOMPATIBLE_ALGORITHM; |
| |
| // We have established that the given key has the correct algorithm, and because this is the |
| // SoftKeymasterContext we can assume that the Key is an AsymmetricKey. So we can downcast. |
| const AsymmetricKey& asymmetric_key = static_cast<const AsymmetricKey&>(key); |
| |
| auto attestation_chain = getAttestationChain(key_algorithm, &error); |
| if (error != KM_ERROR_OK) return error; |
| |
| auto attestation_key = getAttestationKey(key_algorithm, &error); |
| if (error != KM_ERROR_OK) return error; |
| |
| return generate_attestation(asymmetric_key, attest_params, |
| *attestation_chain, *attestation_key, *this, cert_chain); |
| } |
| |
| keymaster_error_t SoftKeymasterContext::UnwrapKey(const KeymasterKeyBlob&, const KeymasterKeyBlob&, |
| const AuthorizationSet&, const KeymasterKeyBlob&, |
| AuthorizationSet*, keymaster_key_format_t*, |
| KeymasterKeyBlob*) const { |
| return KM_ERROR_UNIMPLEMENTED; |
| } |
| |
| } // namespace keymaster |
