/*
|
**
|
** Copyright 2017, 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/key_blob_utils/software_keyblobs.h>
|
|
#include <stdint.h>
|
|
#include <hardware/keymaster_defs.h>
|
|
#include <keymaster/android_keymaster_utils.h>
|
#include <keymaster/authorization_set.h>
|
#include <keymaster/key.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/km_openssl/openssl_utils.h>
|
#include <keymaster/km_openssl/openssl_err.h>
|
#include <keymaster/logger.h>
|
#include <keymaster/UniquePtr.h>
|
|
#include <openssl/aes.h>
|
|
namespace keymaster {
|
|
static uint8_t SWROT[2] = {'S', 'W'};
|
KeymasterBlob softwareRootOfTrust(SWROT);
|
|
namespace {
|
|
bool UpgradeIntegerTag(keymaster_tag_t tag, uint32_t value, AuthorizationSet* set,
|
bool* set_changed) {
|
int index = set->find(tag);
|
if (index == -1) {
|
keymaster_key_param_t param;
|
param.tag = tag;
|
param.integer = value;
|
set->push_back(param);
|
*set_changed = true;
|
return true;
|
}
|
|
if (set->params[index].integer > value)
|
return false;
|
|
if (set->params[index].integer != value) {
|
set->params[index].integer = value;
|
*set_changed = true;
|
}
|
return true;
|
}
|
|
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;
|
}
|
|
} // anonymous namespace
|
|
keymaster_error_t BuildHiddenAuthorizations(const AuthorizationSet& input_set,
|
AuthorizationSet* hidden,
|
const KeymasterBlob& root_of_trust) {
|
keymaster_blob_t entry;
|
if (input_set.GetTagValue(TAG_APPLICATION_ID, &entry))
|
hidden->push_back(TAG_APPLICATION_ID, entry.data, entry.data_length);
|
if (input_set.GetTagValue(TAG_APPLICATION_DATA, &entry))
|
hidden->push_back(TAG_APPLICATION_DATA, entry.data, entry.data_length);
|
|
hidden->push_back(TAG_ROOT_OF_TRUST, root_of_trust);
|
|
return TranslateAuthorizationSetError(hidden->is_valid());
|
}
|
|
keymaster_error_t FakeKeyAuthorizations(EVP_PKEY* pubkey,
|
AuthorizationSet* hw_enforced,
|
AuthorizationSet* sw_enforced) {
|
hw_enforced->Clear();
|
sw_enforced->Clear();
|
|
switch (EVP_PKEY_type(pubkey->type)) {
|
case EVP_PKEY_RSA: {
|
hw_enforced->push_back(TAG_ALGORITHM, KM_ALGORITHM_RSA);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_NONE);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_MD5);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA1);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA_2_224);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA_2_256);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA_2_384);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA_2_512);
|
hw_enforced->push_back(TAG_PADDING, KM_PAD_NONE);
|
hw_enforced->push_back(TAG_PADDING, KM_PAD_RSA_PKCS1_1_5_SIGN);
|
hw_enforced->push_back(TAG_PADDING, KM_PAD_RSA_PKCS1_1_5_ENCRYPT);
|
hw_enforced->push_back(TAG_PADDING, KM_PAD_RSA_PSS);
|
hw_enforced->push_back(TAG_PADDING, KM_PAD_RSA_OAEP);
|
|
sw_enforced->push_back(TAG_PURPOSE, KM_PURPOSE_SIGN);
|
sw_enforced->push_back(TAG_PURPOSE, KM_PURPOSE_VERIFY);
|
sw_enforced->push_back(TAG_PURPOSE, KM_PURPOSE_ENCRYPT);
|
sw_enforced->push_back(TAG_PURPOSE, KM_PURPOSE_DECRYPT);
|
|
RSA_Ptr rsa(EVP_PKEY_get1_RSA(pubkey));
|
if (!rsa)
|
return TranslateLastOpenSslError();
|
hw_enforced->push_back(TAG_KEY_SIZE, RSA_size(rsa.get()) * 8);
|
uint64_t public_exponent = BN_get_word(rsa->e);
|
if (public_exponent == 0xffffffffL)
|
return KM_ERROR_INVALID_KEY_BLOB;
|
hw_enforced->push_back(TAG_RSA_PUBLIC_EXPONENT, public_exponent);
|
break;
|
}
|
|
case EVP_PKEY_EC: {
|
hw_enforced->push_back(TAG_ALGORITHM, KM_ALGORITHM_RSA);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_NONE);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_MD5);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA1);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA_2_224);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA_2_256);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA_2_384);
|
hw_enforced->push_back(TAG_DIGEST, KM_DIGEST_SHA_2_512);
|
|
sw_enforced->push_back(TAG_PURPOSE, KM_PURPOSE_SIGN);
|
sw_enforced->push_back(TAG_PURPOSE, KM_PURPOSE_VERIFY);
|
|
UniquePtr<EC_KEY, EC_KEY_Delete> ec_key(EVP_PKEY_get1_EC_KEY(pubkey));
|
if (!ec_key.get())
|
return TranslateLastOpenSslError();
|
size_t key_size_bits;
|
keymaster_error_t error =
|
ec_get_group_size(EC_KEY_get0_group(ec_key.get()), &key_size_bits);
|
if (error != KM_ERROR_OK)
|
return error;
|
hw_enforced->push_back(TAG_KEY_SIZE, key_size_bits);
|
break;
|
}
|
|
default:
|
return KM_ERROR_UNSUPPORTED_ALGORITHM;
|
}
|
|
sw_enforced->push_back(TAG_ALL_USERS);
|
sw_enforced->push_back(TAG_NO_AUTH_REQUIRED);
|
|
return KM_ERROR_OK;
|
}
|
|
|
// Note: This parsing code in below is from system/security/softkeymaster/keymaster_openssl.cpp's
|
// unwrap_key function, modified for the preferred function signature and formatting. It does some
|
// odd things, but they have been left unchanged to avoid breaking compatibility.
|
static const uint8_t SOFT_KEY_MAGIC[] = {'P', 'K', '#', '8'};
|
keymaster_error_t ParseOldSoftkeymasterBlob(
|
const KeymasterKeyBlob& blob, KeymasterKeyBlob* key_material, AuthorizationSet* hw_enforced,
|
AuthorizationSet* sw_enforced) {
|
long publicLen = 0;
|
long privateLen = 0;
|
const uint8_t* p = blob.key_material;
|
const uint8_t* end = blob.key_material + blob.key_material_size;
|
|
int type = 0;
|
ptrdiff_t min_size =
|
sizeof(SOFT_KEY_MAGIC) + sizeof(type) + sizeof(publicLen) + 1 + sizeof(privateLen) + 1;
|
if (end - p < min_size) {
|
LOG_W("key blob appears to be truncated (if an old SW key)", 0);
|
return KM_ERROR_INVALID_KEY_BLOB;
|
}
|
|
if (memcmp(p, SOFT_KEY_MAGIC, sizeof(SOFT_KEY_MAGIC)) != 0)
|
return KM_ERROR_INVALID_KEY_BLOB;
|
p += sizeof(SOFT_KEY_MAGIC);
|
|
for (size_t i = 0; i < sizeof(type); i++)
|
type = (type << 8) | *p++;
|
|
for (size_t i = 0; i < sizeof(type); i++)
|
publicLen = (publicLen << 8) | *p++;
|
|
if (p + publicLen > end) {
|
LOG_W("public key length encoding error: size=%ld, end=%td", publicLen, end - p);
|
return KM_ERROR_INVALID_KEY_BLOB;
|
}
|
p += publicLen;
|
|
if (end - p < 2) {
|
LOG_W("key blob appears to be truncated (if an old SW key)", 0);
|
return KM_ERROR_INVALID_KEY_BLOB;
|
}
|
|
for (size_t i = 0; i < sizeof(type); i++)
|
privateLen = (privateLen << 8) | *p++;
|
|
if (p + privateLen > end) {
|
LOG_W("private key length encoding error: size=%ld, end=%td", privateLen, end - p);
|
return KM_ERROR_INVALID_KEY_BLOB;
|
}
|
|
// Just to be sure, make sure that the ASN.1 structure parses correctly. We don't actually use
|
// the EVP_PKEY here.
|
const uint8_t* key_start = p;
|
EVP_PKEY_Ptr pkey(d2i_PrivateKey(type, nullptr, &p, privateLen));
|
if (pkey.get() == nullptr) {
|
LOG_W("Failed to parse PKCS#8 key material (if old SW key)", 0);
|
return KM_ERROR_INVALID_KEY_BLOB;
|
}
|
|
// All auths go into sw_enforced, including those that would be HW-enforced if we were faking
|
// auths for a HW-backed key.
|
hw_enforced->Clear();
|
keymaster_error_t error = FakeKeyAuthorizations(pkey.get(), sw_enforced, sw_enforced);
|
if (error != KM_ERROR_OK)
|
return error;
|
|
if (!key_material->Reset(privateLen))
|
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
|
memcpy(key_material->writable_data(), key_start, privateLen);
|
|
return KM_ERROR_OK;
|
}
|
|
static uint8_t master_key_bytes[AES_BLOCK_SIZE] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
|
const KeymasterKeyBlob MASTER_KEY(master_key_bytes, array_length(master_key_bytes));
|
|
keymaster_error_t ParseOcbAuthEncryptedBlob(const KeymasterKeyBlob& blob,
|
const AuthorizationSet& hidden,
|
KeymasterKeyBlob* key_material,
|
AuthorizationSet* hw_enforced,
|
AuthorizationSet* sw_enforced) {
|
Buffer nonce, tag;
|
KeymasterKeyBlob encrypted_key_material;
|
keymaster_error_t error = DeserializeAuthEncryptedBlob(blob, &encrypted_key_material,
|
hw_enforced, sw_enforced, &nonce, &tag);
|
if (error != KM_ERROR_OK)
|
return error;
|
|
if (nonce.available_read() != OCB_NONCE_LENGTH || tag.available_read() != OCB_TAG_LENGTH)
|
return KM_ERROR_INVALID_KEY_BLOB;
|
|
return OcbDecryptKey(*hw_enforced, *sw_enforced, hidden, MASTER_KEY, encrypted_key_material,
|
nonce, tag, key_material);
|
}
|
|
keymaster_error_t SetKeyBlobAuthorizations(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(nullptr)));
|
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 UpgradeSoftKeyBlob(const UniquePtr<Key>& key,
|
const uint32_t os_version, const uint32_t os_patchlevel,
|
const AuthorizationSet& upgrade_params,
|
KeymasterKeyBlob* upgraded_key) {
|
bool set_changed = false;
|
|
if (os_version == 0) {
|
// We need to allow "upgrading" OS version to zero, to support upgrading from proper
|
// numbered releases to unnumbered development and preview releases.
|
|
int key_os_version_pos = key->sw_enforced().find(TAG_OS_VERSION);
|
if (key_os_version_pos != -1) {
|
uint32_t key_os_version = key->sw_enforced()[key_os_version_pos].integer;
|
if (key_os_version != 0) {
|
key->sw_enforced()[key_os_version_pos].integer = os_version;
|
set_changed = true;
|
}
|
}
|
}
|
|
if (!UpgradeIntegerTag(TAG_OS_VERSION, os_version, &key->sw_enforced(), &set_changed) ||
|
!UpgradeIntegerTag(TAG_OS_PATCHLEVEL, os_patchlevel, &key->sw_enforced(), &set_changed))
|
// One of the version fields would have been a downgrade. Not allowed.
|
return KM_ERROR_INVALID_ARGUMENT;
|
|
if (!set_changed)
|
// Dont' need an upgrade.
|
return KM_ERROR_OK;
|
|
AuthorizationSet hidden;
|
auto error = BuildHiddenAuthorizations(upgrade_params, &hidden, softwareRootOfTrust);
|
if (error != KM_ERROR_OK)
|
return error;
|
return SerializeIntegrityAssuredBlob(key->key_material(), hidden, key->hw_enforced(),
|
key->sw_enforced(), upgraded_key);
|
}
|
|
} // namespace keymaster
|
