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PL286/system/keymaster/attestation_record.cpp

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/*
* Copyright 2016 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 "attestation_record.h"
#include <assert.h>
#include <openssl/asn1t.h>
#include "openssl_err.h"
#include "openssl_utils.h"
#include <keymaster/android_keymaster_utils.h>
#include <keymaster/keymaster_context.h>
namespace keymaster {
constexpr uint kCurrentKeymasterVersion = 3;
constexpr uint kCurrentAttestationVersion = 2;
struct stack_st_ASN1_TYPE_Delete {
void operator()(stack_st_ASN1_TYPE* p) { sk_ASN1_TYPE_free(p); }
};
struct ASN1_STRING_Delete {
void operator()(ASN1_STRING* p) { ASN1_STRING_free(p); }
};
struct ASN1_TYPE_Delete {
void operator()(ASN1_TYPE* p) { ASN1_TYPE_free(p); }
};
#define ASN1_INTEGER_SET STACK_OF(ASN1_INTEGER)
typedef struct km_root_of_trust {
ASN1_OCTET_STRING* verified_boot_key;
ASN1_BOOLEAN* device_locked;
ASN1_ENUMERATED* verified_boot_state;
} KM_ROOT_OF_TRUST;
ASN1_SEQUENCE(KM_ROOT_OF_TRUST) = {
ASN1_SIMPLE(KM_ROOT_OF_TRUST, verified_boot_key, ASN1_OCTET_STRING),
ASN1_SIMPLE(KM_ROOT_OF_TRUST, device_locked, ASN1_BOOLEAN),
ASN1_SIMPLE(KM_ROOT_OF_TRUST, verified_boot_state, ASN1_ENUMERATED),
} ASN1_SEQUENCE_END(KM_ROOT_OF_TRUST);
IMPLEMENT_ASN1_FUNCTIONS(KM_ROOT_OF_TRUST);
typedef struct km_auth_list {
ASN1_INTEGER_SET* purpose;
ASN1_INTEGER* algorithm;
ASN1_INTEGER* key_size;
ASN1_INTEGER_SET* digest;
ASN1_INTEGER_SET* padding;
ASN1_INTEGER_SET* kdf;
ASN1_INTEGER* ec_curve;
ASN1_INTEGER* rsa_public_exponent;
ASN1_INTEGER* active_date_time;
ASN1_INTEGER* origination_expire_date_time;
ASN1_INTEGER* usage_expire_date_time;
ASN1_NULL* no_auth_required;
ASN1_INTEGER* user_auth_type;
ASN1_INTEGER* auth_timeout;
ASN1_NULL* allow_while_on_body;
ASN1_NULL* all_applications;
ASN1_OCTET_STRING* application_id;
ASN1_INTEGER* creation_date_time;
ASN1_INTEGER* origin;
ASN1_NULL* rollback_resistant;
KM_ROOT_OF_TRUST* root_of_trust;
ASN1_INTEGER* os_version;
ASN1_INTEGER* os_patchlevel;
ASN1_OCTET_STRING* attestation_application_id;
ASN1_OCTET_STRING* attestation_id_brand;
ASN1_OCTET_STRING* attestation_id_device;
ASN1_OCTET_STRING* attestation_id_product;
ASN1_OCTET_STRING* attestation_id_serial;
ASN1_OCTET_STRING* attestation_id_imei;
ASN1_OCTET_STRING* attestation_id_meid;
ASN1_OCTET_STRING* attestation_id_manufacturer;
ASN1_OCTET_STRING* attestation_id_model;
} KM_AUTH_LIST;
ASN1_SEQUENCE(KM_AUTH_LIST) = {
ASN1_EXP_SET_OF_OPT(KM_AUTH_LIST, purpose, ASN1_INTEGER, TAG_PURPOSE.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, algorithm, ASN1_INTEGER, TAG_ALGORITHM.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, key_size, ASN1_INTEGER, TAG_KEY_SIZE.masked_tag()),
ASN1_EXP_SET_OF_OPT(KM_AUTH_LIST, digest, ASN1_INTEGER, TAG_DIGEST.masked_tag()),
ASN1_EXP_SET_OF_OPT(KM_AUTH_LIST, padding, ASN1_INTEGER, TAG_PADDING.masked_tag()),
ASN1_EXP_SET_OF_OPT(KM_AUTH_LIST, kdf, ASN1_INTEGER, TAG_KDF.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, ec_curve, ASN1_INTEGER, TAG_EC_CURVE.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, rsa_public_exponent, ASN1_INTEGER,
TAG_RSA_PUBLIC_EXPONENT.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, active_date_time, ASN1_INTEGER, TAG_ACTIVE_DATETIME.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, origination_expire_date_time, ASN1_INTEGER,
TAG_ORIGINATION_EXPIRE_DATETIME.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, usage_expire_date_time, ASN1_INTEGER,
TAG_USAGE_EXPIRE_DATETIME.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, no_auth_required, ASN1_NULL, TAG_NO_AUTH_REQUIRED.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, user_auth_type, ASN1_INTEGER, TAG_USER_AUTH_TYPE.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, auth_timeout, ASN1_INTEGER, TAG_AUTH_TIMEOUT.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, allow_while_on_body, ASN1_NULL,
TAG_ALLOW_WHILE_ON_BODY.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, all_applications, ASN1_NULL, TAG_ALL_APPLICATIONS.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, application_id, ASN1_OCTET_STRING, TAG_APPLICATION_ID.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, creation_date_time, ASN1_INTEGER,
TAG_CREATION_DATETIME.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, origin, ASN1_INTEGER, TAG_ORIGIN.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, rollback_resistant, ASN1_NULL, TAG_ROLLBACK_RESISTANT.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, root_of_trust, KM_ROOT_OF_TRUST, TAG_ROOT_OF_TRUST.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, os_version, ASN1_INTEGER, TAG_OS_VERSION.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, os_patchlevel, ASN1_INTEGER, TAG_OS_PATCHLEVEL.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, attestation_application_id, ASN1_OCTET_STRING,
TAG_ATTESTATION_APPLICATION_ID.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_brand, ASN1_OCTET_STRING,
TAG_ATTESTATION_ID_BRAND.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_device, ASN1_OCTET_STRING,
TAG_ATTESTATION_ID_DEVICE.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_product, ASN1_OCTET_STRING,
TAG_ATTESTATION_ID_PRODUCT.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_serial, ASN1_OCTET_STRING,
TAG_ATTESTATION_ID_SERIAL.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_imei, ASN1_OCTET_STRING,
TAG_ATTESTATION_ID_IMEI.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_meid, ASN1_OCTET_STRING,
TAG_ATTESTATION_ID_MEID.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_manufacturer, ASN1_OCTET_STRING,
TAG_ATTESTATION_ID_MANUFACTURER.masked_tag()),
ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_model, ASN1_OCTET_STRING,
TAG_ATTESTATION_ID_MODEL.masked_tag()),
} ASN1_SEQUENCE_END(KM_AUTH_LIST);
IMPLEMENT_ASN1_FUNCTIONS(KM_AUTH_LIST);
typedef struct km_key_description {
ASN1_INTEGER* attestation_version;
ASN1_ENUMERATED* attestation_security_level;
ASN1_INTEGER* keymaster_version;
ASN1_ENUMERATED* keymaster_security_level;
ASN1_OCTET_STRING* attestation_challenge;
KM_AUTH_LIST* software_enforced;
KM_AUTH_LIST* tee_enforced;
ASN1_INTEGER* unique_id;
} KM_KEY_DESCRIPTION;
ASN1_SEQUENCE(KM_KEY_DESCRIPTION) = {
ASN1_SIMPLE(KM_KEY_DESCRIPTION, attestation_version, ASN1_INTEGER),
ASN1_SIMPLE(KM_KEY_DESCRIPTION, attestation_security_level, ASN1_ENUMERATED),
ASN1_SIMPLE(KM_KEY_DESCRIPTION, keymaster_version, ASN1_INTEGER),
ASN1_SIMPLE(KM_KEY_DESCRIPTION, keymaster_security_level, ASN1_ENUMERATED),
ASN1_SIMPLE(KM_KEY_DESCRIPTION, attestation_challenge, ASN1_OCTET_STRING),
ASN1_SIMPLE(KM_KEY_DESCRIPTION, unique_id, ASN1_OCTET_STRING),
ASN1_SIMPLE(KM_KEY_DESCRIPTION, software_enforced, KM_AUTH_LIST),
ASN1_SIMPLE(KM_KEY_DESCRIPTION, tee_enforced, KM_AUTH_LIST),
} ASN1_SEQUENCE_END(KM_KEY_DESCRIPTION);
IMPLEMENT_ASN1_FUNCTIONS(KM_KEY_DESCRIPTION);
static const keymaster_tag_t kDeviceAttestationTags[] = {
KM_TAG_ATTESTATION_ID_BRAND,
KM_TAG_ATTESTATION_ID_DEVICE,
KM_TAG_ATTESTATION_ID_PRODUCT,
KM_TAG_ATTESTATION_ID_SERIAL,
KM_TAG_ATTESTATION_ID_IMEI,
KM_TAG_ATTESTATION_ID_MEID,
KM_TAG_ATTESTATION_ID_MANUFACTURER,
KM_TAG_ATTESTATION_ID_MODEL,
};
struct KM_AUTH_LIST_Delete {
void operator()(KM_AUTH_LIST* p) { KM_AUTH_LIST_free(p); }
};
struct KM_KEY_DESCRIPTION_Delete {
void operator()(KM_KEY_DESCRIPTION* p) { KM_KEY_DESCRIPTION_free(p); }
};
static uint32_t get_uint32_value(const keymaster_key_param_t& param) {
switch (keymaster_tag_get_type(param.tag)) {
case KM_ENUM:
case KM_ENUM_REP:
return param.enumerated;
case KM_UINT:
case KM_UINT_REP:
return param.integer;
default:
assert(false);
return 0xFFFFFFFF;
}
}
// Insert value in either the dest_integer or the dest_integer_set, whichever is provided.
static keymaster_error_t insert_integer(ASN1_INTEGER* value, ASN1_INTEGER** dest_integer,
ASN1_INTEGER_SET** dest_integer_set) {
assert((dest_integer == nullptr) ^ (dest_integer_set == nullptr));
assert(value);
if (dest_integer_set) {
if (!*dest_integer_set)
*dest_integer_set = sk_ASN1_INTEGER_new_null();
if (!*dest_integer_set)
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
if (!sk_ASN1_INTEGER_push(*dest_integer_set, value))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
return KM_ERROR_OK;
} else if (dest_integer) {
if (*dest_integer)
ASN1_INTEGER_free(*dest_integer);
*dest_integer = value;
return KM_ERROR_OK;
}
assert(false); // Should never get here.
return KM_ERROR_OK;
}
// Put the contents of the keymaster AuthorizationSet auth_list in to the ASN.1 record structure,
// record.
static keymaster_error_t build_auth_list(const AuthorizationSet& auth_list, KM_AUTH_LIST* record) {
assert(record);
if (auth_list.empty())
return KM_ERROR_OK;
for (auto entry : auth_list) {
ASN1_INTEGER_SET** integer_set = nullptr;
ASN1_INTEGER** integer_ptr = nullptr;
ASN1_OCTET_STRING** string_ptr = nullptr;
ASN1_NULL** bool_ptr = nullptr;
switch (entry.tag) {
/* Ignored tags */
case KM_TAG_INVALID:
case KM_TAG_ASSOCIATED_DATA:
case KM_TAG_NONCE:
case KM_TAG_AUTH_TOKEN:
case KM_TAG_MAC_LENGTH:
case KM_TAG_ALL_USERS:
case KM_TAG_USER_ID:
case KM_TAG_USER_SECURE_ID:
case KM_TAG_EXPORTABLE:
case KM_TAG_RESET_SINCE_ID_ROTATION:
case KM_TAG_ATTESTATION_CHALLENGE:
case KM_TAG_BLOCK_MODE:
case KM_TAG_CALLER_NONCE:
case KM_TAG_MIN_MAC_LENGTH:
case KM_TAG_ECIES_SINGLE_HASH_MODE:
case KM_TAG_INCLUDE_UNIQUE_ID:
case KM_TAG_BLOB_USAGE_REQUIREMENTS:
case KM_TAG_BOOTLOADER_ONLY:
case KM_TAG_MIN_SECONDS_BETWEEN_OPS:
case KM_TAG_MAX_USES_PER_BOOT:
case KM_TAG_APPLICATION_DATA:
case KM_TAG_UNIQUE_ID:
case KM_TAG_ROOT_OF_TRUST:
continue;
/* Non-repeating enumerations */
case KM_TAG_ALGORITHM:
integer_ptr = &record->algorithm;
break;
case KM_TAG_EC_CURVE:
integer_ptr = &record->ec_curve;
break;
case KM_TAG_USER_AUTH_TYPE:
integer_ptr = &record->user_auth_type;
break;
case KM_TAG_ORIGIN:
integer_ptr = &record->origin;
break;
/* Repeating enumerations */
case KM_TAG_PURPOSE:
integer_set = &record->purpose;
break;
case KM_TAG_PADDING:
integer_set = &record->padding;
break;
case KM_TAG_DIGEST:
integer_set = &record->digest;
break;
case KM_TAG_KDF:
integer_set = &record->kdf;
break;
/* Non-repeating unsigned integers */
case KM_TAG_KEY_SIZE:
integer_ptr = &record->key_size;
break;
case KM_TAG_AUTH_TIMEOUT:
integer_ptr = &record->auth_timeout;
break;
case KM_TAG_OS_VERSION:
integer_ptr = &record->os_version;
break;
case KM_TAG_OS_PATCHLEVEL:
integer_ptr = &record->os_patchlevel;
break;
/* Non-repeating long unsigned integers */
case KM_TAG_RSA_PUBLIC_EXPONENT:
integer_ptr = &record->rsa_public_exponent;
break;
/* Dates */
case KM_TAG_ACTIVE_DATETIME:
integer_ptr = &record->active_date_time;
break;
case KM_TAG_ORIGINATION_EXPIRE_DATETIME:
integer_ptr = &record->origination_expire_date_time;
break;
case KM_TAG_USAGE_EXPIRE_DATETIME:
integer_ptr = &record->usage_expire_date_time;
break;
case KM_TAG_CREATION_DATETIME:
integer_ptr = &record->creation_date_time;
break;
/* Booleans */
case KM_TAG_NO_AUTH_REQUIRED:
bool_ptr = &record->no_auth_required;
break;
case KM_TAG_ALL_APPLICATIONS:
bool_ptr = &record->all_applications;
break;
case KM_TAG_ROLLBACK_RESISTANT:
bool_ptr = &record->rollback_resistant;
break;
case KM_TAG_ALLOW_WHILE_ON_BODY:
bool_ptr = &record->allow_while_on_body;
break;
/* Byte arrays*/
case KM_TAG_APPLICATION_ID:
string_ptr = &record->application_id;
break;
case KM_TAG_ATTESTATION_APPLICATION_ID:
string_ptr = &record->attestation_application_id;
break;
case KM_TAG_ATTESTATION_ID_BRAND:
string_ptr = &record->attestation_id_brand;
break;
case KM_TAG_ATTESTATION_ID_DEVICE:
string_ptr = &record->attestation_id_device;
break;
case KM_TAG_ATTESTATION_ID_PRODUCT:
string_ptr = &record->attestation_id_product;
break;
case KM_TAG_ATTESTATION_ID_SERIAL:
string_ptr = &record->attestation_id_serial;
break;
case KM_TAG_ATTESTATION_ID_IMEI:
string_ptr = &record->attestation_id_imei;
break;
case KM_TAG_ATTESTATION_ID_MEID:
string_ptr = &record->attestation_id_meid;
break;
case KM_TAG_ATTESTATION_ID_MANUFACTURER:
string_ptr = &record->attestation_id_manufacturer;
break;
case KM_TAG_ATTESTATION_ID_MODEL:
string_ptr = &record->attestation_id_model;
break;
}
keymaster_tag_type_t type = keymaster_tag_get_type(entry.tag);
switch (type) {
case KM_ENUM:
case KM_ENUM_REP:
case KM_UINT:
case KM_UINT_REP: {
assert((keymaster_tag_repeatable(entry.tag) && integer_set) ||
(!keymaster_tag_repeatable(entry.tag) && integer_ptr));
UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(ASN1_INTEGER_new());
if (!value.get())
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
if (!ASN1_INTEGER_set(value.get(), get_uint32_value(entry)))
return TranslateLastOpenSslError();
insert_integer(value.release(), integer_ptr, integer_set);
break;
}
case KM_ULONG:
case KM_ULONG_REP:
case KM_DATE: {
assert((keymaster_tag_repeatable(entry.tag) && integer_set) ||
(!keymaster_tag_repeatable(entry.tag) && integer_ptr));
UniquePtr<BIGNUM, BIGNUM_Delete> bn_value(BN_new());
if (!bn_value.get())
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
if (type == KM_DATE) {
if (!BN_set_u64(bn_value.get(), entry.date_time)) {
return TranslateLastOpenSslError();
}
} else {
if (!BN_set_u64(bn_value.get(), entry.long_integer)) {
return TranslateLastOpenSslError();
}
}
UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(
BN_to_ASN1_INTEGER(bn_value.get(), nullptr));
if (!value.get())
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
insert_integer(value.release(), integer_ptr, integer_set);
break;
}
case KM_BOOL:
assert(bool_ptr);
if (!*bool_ptr)
*bool_ptr = ASN1_NULL_new();
if (!*bool_ptr)
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
break;
/* Byte arrays*/
case KM_BYTES:
assert(string_ptr);
if (!*string_ptr)
*string_ptr = ASN1_OCTET_STRING_new();
if (!*string_ptr)
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
if (!ASN1_OCTET_STRING_set(*string_ptr, entry.blob.data, entry.blob.data_length))
return TranslateLastOpenSslError();
break;
default:
return KM_ERROR_UNIMPLEMENTED;
}
}
keymaster_ec_curve_t ec_curve;
uint32_t key_size;
if (auth_list.Contains(TAG_ALGORITHM, KM_ALGORITHM_EC) && //
!auth_list.Contains(TAG_EC_CURVE) && //
auth_list.GetTagValue(TAG_KEY_SIZE, &key_size)) {
// This must be a keymaster1 key. It's an EC key with no curve. Insert the curve.
keymaster_error_t error = EcKeySizeToCurve(key_size, &ec_curve);
if (error != KM_ERROR_OK)
return error;
UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(ASN1_INTEGER_new());
if (!value.get())
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
if (!ASN1_INTEGER_set(value.get(), ec_curve))
return TranslateLastOpenSslError();
insert_integer(value.release(), &record->ec_curve, nullptr);
}
return KM_ERROR_OK;
}
// Construct an ASN1.1 DER-encoded attestation record containing the values from sw_enforced and
// tee_enforced.
keymaster_error_t build_attestation_record(const AuthorizationSet& attestation_params,
AuthorizationSet sw_enforced,
AuthorizationSet tee_enforced,
const KeymasterContext& context,
UniquePtr<uint8_t[]>* asn1_key_desc,
size_t* asn1_key_desc_len) {
assert(asn1_key_desc && asn1_key_desc_len);
UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> key_desc(KM_KEY_DESCRIPTION_new());
if (!key_desc.get())
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
keymaster_security_level_t keymaster_security_level;
uint32_t keymaster_version = UINT32_MAX;
if (tee_enforced.empty()) {
// Software key.
keymaster_security_level = KM_SECURITY_LEVEL_SOFTWARE;
keymaster_version = kCurrentKeymasterVersion;
} else {
keymaster_security_level = KM_SECURITY_LEVEL_TRUSTED_ENVIRONMENT;
switch (context.GetSecurityLevel()) {
case KM_SECURITY_LEVEL_TRUSTED_ENVIRONMENT: {
keymaster_version = kCurrentKeymasterVersion;
// Root of trust is only available in TEE
KM_AUTH_LIST* tee_record = key_desc->tee_enforced;
tee_record->root_of_trust = KM_ROOT_OF_TRUST_new();
keymaster_blob_t verified_boot_key;
keymaster_verified_boot_t verified_boot_state;
bool device_locked;
keymaster_error_t error = context.GetVerifiedBootParams(
&verified_boot_key, &verified_boot_state, &device_locked);
if (error != KM_ERROR_OK)
return error;
if (verified_boot_key.data_length &&
!ASN1_OCTET_STRING_set(tee_record->root_of_trust->verified_boot_key,
verified_boot_key.data, verified_boot_key.data_length))
return TranslateLastOpenSslError();
tee_record->root_of_trust->device_locked = (int*)device_locked;
if (!ASN1_ENUMERATED_set(tee_record->root_of_trust->verified_boot_state,
verified_boot_state))
return TranslateLastOpenSslError();
break;
}
case KM_SECURITY_LEVEL_SOFTWARE:
// We're running in software, wrapping some KM hardware. Is it KM0 or KM1? KM1 keys
// have the purpose in the tee_enforced list. It's possible that a key could be created
// without a purpose, which would fool this test into reporting it's a KM0 key. That
// corner case doesn't matter much, because purpose-less keys are not usable anyway.
// Also, KM1 TEEs should disappear rapidly.
keymaster_version = tee_enforced.Contains(TAG_PURPOSE) ? 1 : 0;
break;
}
if (keymaster_version == UINT32_MAX)
return KM_ERROR_UNKNOWN_ERROR;
}
if (!ASN1_INTEGER_set(key_desc->attestation_version, kCurrentAttestationVersion) ||
!ASN1_ENUMERATED_set(key_desc->attestation_security_level, context.GetSecurityLevel()) ||
!ASN1_INTEGER_set(key_desc->keymaster_version, keymaster_version) ||
!ASN1_ENUMERATED_set(key_desc->keymaster_security_level, keymaster_security_level))
return TranslateLastOpenSslError();
keymaster_blob_t attestation_challenge = {nullptr, 0};
if (!attestation_params.GetTagValue(TAG_ATTESTATION_CHALLENGE, &attestation_challenge))
return KM_ERROR_ATTESTATION_CHALLENGE_MISSING;
if (!ASN1_OCTET_STRING_set(key_desc->attestation_challenge, attestation_challenge.data,
attestation_challenge.data_length))
return TranslateLastOpenSslError();
keymaster_blob_t attestation_app_id;
if (!attestation_params.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &attestation_app_id))
return KM_ERROR_ATTESTATION_APPLICATION_ID_MISSING;
sw_enforced.push_back(TAG_ATTESTATION_APPLICATION_ID, attestation_app_id);
keymaster_error_t error = context.VerifyAndCopyDeviceIds(attestation_params,
keymaster_security_level == KM_SECURITY_LEVEL_SOFTWARE ? &sw_enforced : &tee_enforced);
if (error == KM_ERROR_UNIMPLEMENTED) {
// The KeymasterContext implementation does not support device ID attestation. Bail out if
// device ID attestation is being attempted.
for (const auto& tag : kDeviceAttestationTags) {
if (attestation_params.find(tag) != -1) {
return KM_ERROR_CANNOT_ATTEST_IDS;
}
}
} else if (error != KM_ERROR_OK) {
return error;
}
error = build_auth_list(sw_enforced, key_desc->software_enforced);
if (error != KM_ERROR_OK)
return error;
error = build_auth_list(tee_enforced, key_desc->tee_enforced);
if (error != KM_ERROR_OK)
return error;
// Only check tee_enforced for TAG_INCLUDE_UNIQUE_ID. If we don't have hardware we can't
// generate unique IDs.
if (tee_enforced.GetTagValue(TAG_INCLUDE_UNIQUE_ID)) {
uint64_t creation_datetime;
// Only check sw_enforced for TAG_CREATION_DATETIME, since it shouldn't be in tee_enforced,
// since this implementation has no secure wall clock.
if (!sw_enforced.GetTagValue(TAG_CREATION_DATETIME, &creation_datetime)) {
LOG_E("Unique ID cannot be created without creation datetime", 0);
return KM_ERROR_INVALID_KEY_BLOB;
}
keymaster_blob_t application_id = {nullptr, 0};
sw_enforced.GetTagValue(TAG_APPLICATION_ID, &application_id);
Buffer unique_id;
error = context.GenerateUniqueId(
creation_datetime, application_id,
attestation_params.GetTagValue(TAG_RESET_SINCE_ID_ROTATION), &unique_id);
if (error != KM_ERROR_OK)
return error;
key_desc->unique_id = ASN1_OCTET_STRING_new();
if (!key_desc->unique_id ||
!ASN1_OCTET_STRING_set(key_desc->unique_id, unique_id.peek_read(),
unique_id.available_read()))
return TranslateLastOpenSslError();
}
int len = i2d_KM_KEY_DESCRIPTION(key_desc.get(), nullptr);
if (len < 0)
return TranslateLastOpenSslError();
*asn1_key_desc_len = len;
asn1_key_desc->reset(new(std::nothrow) uint8_t[*asn1_key_desc_len]);
if (!asn1_key_desc->get())
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
uint8_t* p = asn1_key_desc->get();
len = i2d_KM_KEY_DESCRIPTION(key_desc.get(), &p);
if (len < 0)
return TranslateLastOpenSslError();
return KM_ERROR_OK;
}
// Copy all enumerated values with the specified tag from stack to auth_list.
static bool get_repeated_enums(const stack_st_ASN1_INTEGER* stack, keymaster_tag_t tag,
AuthorizationSet* auth_list) {
assert(keymaster_tag_get_type(tag) == KM_ENUM_REP);
for (size_t i = 0; i < sk_ASN1_INTEGER_num(stack); ++i) {
if (!auth_list->push_back(
keymaster_param_enum(tag, ASN1_INTEGER_get(sk_ASN1_INTEGER_value(stack, i)))))
return false;
}
return true;
}
// Add the specified integer tag/value pair to auth_list.
template <keymaster_tag_type_t Type, keymaster_tag_t Tag, typename KeymasterEnum>
static bool get_enum(const ASN1_INTEGER* asn1_int, TypedEnumTag<Type, Tag, KeymasterEnum> tag,
AuthorizationSet* auth_list) {
if (!asn1_int)
return true;
return auth_list->push_back(tag, static_cast<KeymasterEnum>(ASN1_INTEGER_get(asn1_int)));
}
// Add the specified ulong tag/value pair to auth_list.
static bool get_ulong(const ASN1_INTEGER* asn1_int, keymaster_tag_t tag,
AuthorizationSet* auth_list) {
if (!asn1_int)
return true;
UniquePtr<BIGNUM, BIGNUM_Delete> bn(ASN1_INTEGER_to_BN(asn1_int, nullptr));
if (!bn.get())
return false;
uint64_t ulong = BN_get_word(bn.get());
return auth_list->push_back(keymaster_param_long(tag, ulong));
}
// Extract the values from the specified ASN.1 record and place them in auth_list.
static keymaster_error_t extract_auth_list(const KM_AUTH_LIST* record,
AuthorizationSet* auth_list) {
if (!record)
return KM_ERROR_OK;
// Purpose
if (!get_repeated_enums(record->purpose, TAG_PURPOSE, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Algorithm
if (!get_enum(record->algorithm, TAG_ALGORITHM, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Key size
if (record->key_size && !auth_list->push_back(TAG_KEY_SIZE, ASN1_INTEGER_get(record->key_size)))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Digest
if (!get_repeated_enums(record->digest, TAG_DIGEST, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Padding
if (!get_repeated_enums(record->padding, TAG_PADDING, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// EC curve
if (!get_enum(record->ec_curve, TAG_EC_CURVE, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// RSA public exponent
if (!get_ulong(record->rsa_public_exponent, TAG_RSA_PUBLIC_EXPONENT, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Active date time
if (!get_ulong(record->active_date_time, TAG_ACTIVE_DATETIME, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Origination expire date time
if (!get_ulong(record->origination_expire_date_time, TAG_ORIGINATION_EXPIRE_DATETIME,
auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Usage Expire date time
if (!get_ulong(record->usage_expire_date_time, TAG_USAGE_EXPIRE_DATETIME, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// No auth required
if (record->no_auth_required && !auth_list->push_back(TAG_NO_AUTH_REQUIRED))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// User auth type
if (!get_enum(record->user_auth_type, TAG_USER_AUTH_TYPE, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Auth timeout
if (record->auth_timeout &&
!auth_list->push_back(TAG_AUTH_TIMEOUT, ASN1_INTEGER_get(record->auth_timeout)))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// All applications
if (record->all_applications && !auth_list->push_back(TAG_ALL_APPLICATIONS))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Application ID
if (record->application_id &&
!auth_list->push_back(TAG_APPLICATION_ID, record->application_id->data,
record->application_id->length))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Creation date time
if (!get_ulong(record->creation_date_time, TAG_CREATION_DATETIME, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Origin
if (!get_enum(record->origin, TAG_ORIGIN, auth_list))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Rollback resistant
if (record->rollback_resistant && !auth_list->push_back(TAG_ROLLBACK_RESISTANT))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Root of trust
if (record->root_of_trust) {
KM_ROOT_OF_TRUST* rot = record->root_of_trust;
if (!rot->verified_boot_key)
return KM_ERROR_INVALID_KEY_BLOB;
// Other root of trust fields are not mapped to auth set entries.
}
// OS Version
if (record->os_version &&
!auth_list->push_back(TAG_OS_VERSION, ASN1_INTEGER_get(record->os_version)))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// OS Patch level
if (record->os_patchlevel &&
!auth_list->push_back(TAG_OS_PATCHLEVEL, ASN1_INTEGER_get(record->os_patchlevel)))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Brand name
if (record->attestation_id_brand &&
!auth_list->push_back(TAG_ATTESTATION_ID_BRAND, record->attestation_id_brand->data,
record->attestation_id_brand->length))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Device name
if (record->attestation_id_device &&
!auth_list->push_back(TAG_ATTESTATION_ID_DEVICE, record->attestation_id_device->data,
record->attestation_id_device->length))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Product name
if (record->attestation_id_product &&
!auth_list->push_back(TAG_ATTESTATION_ID_PRODUCT, record->attestation_id_product->data,
record->attestation_id_product->length))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Serial number
if (record->attestation_id_serial &&
!auth_list->push_back(TAG_ATTESTATION_ID_SERIAL, record->attestation_id_serial->data,
record->attestation_id_serial->length))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// IMEI
if (record->attestation_id_imei &&
!auth_list->push_back(TAG_ATTESTATION_ID_IMEI, record->attestation_id_imei->data,
record->attestation_id_imei->length))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// MEID
if (record->attestation_id_meid &&
!auth_list->push_back(TAG_ATTESTATION_ID_MEID, record->attestation_id_meid->data,
record->attestation_id_meid->length))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Manufacturer name
if (record->attestation_id_manufacturer &&
!auth_list->push_back(TAG_ATTESTATION_ID_MANUFACTURER,
record->attestation_id_manufacturer->data,
record->attestation_id_manufacturer->length))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
// Model name
if (record->attestation_id_model &&
!auth_list->push_back(TAG_ATTESTATION_ID_MODEL, record->attestation_id_model->data,
record->attestation_id_model->length))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
return KM_ERROR_OK;
}
// Parse the DER-encoded attestation record, placing the results in keymaster_version,
// attestation_challenge, software_enforced, tee_enforced and unique_id.
keymaster_error_t parse_attestation_record(const uint8_t* asn1_key_desc, size_t asn1_key_desc_len,
uint32_t* attestation_version, //
keymaster_security_level_t* attestation_security_level,
uint32_t* keymaster_version,
keymaster_security_level_t* keymaster_security_level,
keymaster_blob_t* attestation_challenge,
AuthorizationSet* software_enforced,
AuthorizationSet* tee_enforced,
keymaster_blob_t* unique_id) {
const uint8_t* p = asn1_key_desc;
UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> record(
d2i_KM_KEY_DESCRIPTION(nullptr, &p, asn1_key_desc_len));
if (!record.get())
return TranslateLastOpenSslError();
*attestation_version = ASN1_INTEGER_get(record->attestation_version);
*attestation_security_level = static_cast<keymaster_security_level_t>(
ASN1_ENUMERATED_get(record->attestation_security_level));
*keymaster_version = ASN1_INTEGER_get(record->keymaster_version);
*keymaster_security_level = static_cast<keymaster_security_level_t>(
ASN1_ENUMERATED_get(record->keymaster_security_level));
attestation_challenge->data =
dup_buffer(record->attestation_challenge->data, record->attestation_challenge->length);
attestation_challenge->data_length = record->attestation_challenge->length;
unique_id->data = dup_buffer(record->unique_id->data, record->unique_id->length);
unique_id->data_length = record->unique_id->length;
keymaster_error_t error = extract_auth_list(record->software_enforced, software_enforced);
if (error != KM_ERROR_OK)
return error;
return extract_auth_list(record->tee_enforced, tee_enforced);
}
} // namespace keymaster