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// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/extensions/api/enterprise_platform_keys_private/enterprise_platform_keys_private_api.h"
#include "base/base64.h"
#include "base/bind.h"
#include "base/task/post_task.h"
#include "base/values.h"
#include "chrome/browser/chromeos/profiles/profile_helper.h"
#include "chrome/browser/extensions/chrome_extension_function_details.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/extensions/api/enterprise_platform_keys_private.h"
#include "chrome/common/pref_names.h"
#include "components/pref_registry/pref_registry_syncable.h"
#include "components/prefs/pref_service.h"
#include "content/public/browser/browser_task_traits.h"
#include "content/public/browser/browser_thread.h"
#include "extensions/common/manifest.h"
namespace {
// Prefix for naming machine keys used for SignedPublicKeyAndChallenge when
// challenging the EMK with register=true.
const char kEnterpriseMachineKeyForSpkacPrefix[] = "attest-ent-machine-";
} // namespace
namespace extensions {
namespace api_epkp = api::enterprise_platform_keys_private;
EPKPChallengeKey::EPKPChallengeKey() = default;
EPKPChallengeKey::~EPKPChallengeKey() = default;
void EPKPChallengeKey::RegisterProfilePrefs(
user_prefs::PrefRegistrySyncable* registry) {
registry->RegisterListPref(prefs::kAttestationExtensionWhitelist);
}
const char EPKPChallengeKey::kExtensionNotWhitelistedError[] =
"The extension does not have permission to call this function.";
const char EPKPChallengeKey::kChallengeBadBase64Error[] =
"Challenge is not base64 encoded.";
// Check if the extension is whitelisted in the user policy.
bool EPKPChallengeKey::IsExtensionWhitelisted(
Profile* profile,
scoped_refptr<const Extension> extension) {
if (!chromeos::ProfileHelper::Get()->GetUserByProfile(profile)) {
// Only allow remote attestation for apps that were force-installed on the
// login/signin screen.
// TODO(drcrash): Use a separate device-wide policy for the API.
return Manifest::IsPolicyLocation(extension->location());
}
if (Manifest::IsComponentLocation(extension->location())) {
// Note: For this to even be called, the component extension must also be
// whitelisted in chrome/common/extensions/api/_permission_features.json
return true;
}
const base::ListValue* list =
profile->GetPrefs()->GetList(prefs::kAttestationExtensionWhitelist);
base::Value value(extension->id());
return list->Find(value) != list->end();
}
void EPKPChallengeKey::Run(
chromeos::attestation::AttestationKeyType type,
scoped_refptr<ExtensionFunction> caller,
chromeos::attestation::TpmChallengeKeyCallback callback,
const std::string& challenge,
bool register_key) {
Profile* profile = ChromeExtensionFunctionDetails(caller.get()).GetProfile();
if (!IsExtensionWhitelisted(profile, caller->extension())) {
std::move(callback).Run(
chromeos::attestation::TpmChallengeKeyResult::MakeError(
kExtensionNotWhitelistedError));
return;
}
std::string key_name_for_spkac;
if (register_key && (type == chromeos::attestation::KEY_DEVICE)) {
key_name_for_spkac =
kEnterpriseMachineKeyForSpkacPrefix + caller->extension()->id();
}
impl_ = chromeos::attestation::TpmChallengeKeyFactory::Create();
impl_->Run(type, profile, std::move(callback), challenge, register_key,
key_name_for_spkac);
}
EnterprisePlatformKeysPrivateChallengeMachineKeyFunction::
EnterprisePlatformKeysPrivateChallengeMachineKeyFunction() = default;
EnterprisePlatformKeysPrivateChallengeMachineKeyFunction::
~EnterprisePlatformKeysPrivateChallengeMachineKeyFunction() = default;
ExtensionFunction::ResponseAction
EnterprisePlatformKeysPrivateChallengeMachineKeyFunction::Run() {
std::unique_ptr<api_epkp::ChallengeMachineKey::Params> params(
api_epkp::ChallengeMachineKey::Params::Create(*args_));
EXTENSION_FUNCTION_VALIDATE(params);
chromeos::attestation::TpmChallengeKeyCallback callback =
base::Bind(&EnterprisePlatformKeysPrivateChallengeMachineKeyFunction::
OnChallengedKey,
this);
std::string challenge;
if (!base::Base64Decode(params->challenge, &challenge)) {
return RespondNow(Error(EPKPChallengeKey::kChallengeBadBase64Error));
}
// base::Unretained is safe on impl_ since its life-cycle matches |this| and
// |callback| holds a reference to |this|.
base::OnceClosure task = base::BindOnce(
&EPKPChallengeKey::Run, base::Unretained(&impl_),
chromeos::attestation::KEY_DEVICE, scoped_refptr<ExtensionFunction>(this),
std::move(callback), challenge,
/*register_key=*/false);
base::PostTask(FROM_HERE, {content::BrowserThread::UI}, std::move(task));
return RespondLater();
}
void EnterprisePlatformKeysPrivateChallengeMachineKeyFunction::OnChallengedKey(
const chromeos::attestation::TpmChallengeKeyResult& result) {
if (result.is_success) {
std::string encoded_response;
base::Base64Encode(result.data, &encoded_response);
Respond(ArgumentList(
api_epkp::ChallengeMachineKey::Results::Create(encoded_response)));
} else {
Respond(Error(result.error_message));
}
}
EnterprisePlatformKeysPrivateChallengeUserKeyFunction::
EnterprisePlatformKeysPrivateChallengeUserKeyFunction() = default;
EnterprisePlatformKeysPrivateChallengeUserKeyFunction::
~EnterprisePlatformKeysPrivateChallengeUserKeyFunction() = default;
ExtensionFunction::ResponseAction
EnterprisePlatformKeysPrivateChallengeUserKeyFunction::Run() {
std::unique_ptr<api_epkp::ChallengeUserKey::Params> params(
api_epkp::ChallengeUserKey::Params::Create(*args_));
EXTENSION_FUNCTION_VALIDATE(params);
chromeos::attestation::TpmChallengeKeyCallback callback = base::Bind(
&EnterprisePlatformKeysPrivateChallengeUserKeyFunction::OnChallengedKey,
this);
std::string challenge;
if (!base::Base64Decode(params->challenge, &challenge)) {
return RespondNow(Error(EPKPChallengeKey::kChallengeBadBase64Error));
}
// base::Unretained is safe on impl_ since its life-cycle matches |this| and
// |callback| holds a reference to |this|.
base::OnceClosure task = base::BindOnce(
&EPKPChallengeKey::Run, base::Unretained(&impl_),
chromeos::attestation::KEY_USER, scoped_refptr<ExtensionFunction>(this),
std::move(callback), challenge, params->register_key);
base::PostTask(FROM_HERE, {content::BrowserThread::UI}, std::move(task));
return RespondLater();
}
void EnterprisePlatformKeysPrivateChallengeUserKeyFunction::OnChallengedKey(
const chromeos::attestation::TpmChallengeKeyResult& result) {
if (result.is_success) {
std::string encoded_response;
base::Base64Encode(result.data, &encoded_response);
Respond(ArgumentList(
api_epkp::ChallengeUserKey::Results::Create(encoded_response)));
} else {
Respond(Error(result.error_message));
}
}
} // namespace extensions
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