src/privet/auth_manager.cc - weave/libweave - Git at Google

 // Copyright 2015 The Weave 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 "src/privet/auth_manager.h"

 #include <base/rand_util.h>
 #include <base/strings/string_number_conversions.h>

 #include "src/config.h"
 #include "src/data_encoding.h"
 #include "src/privet/constants.h"
 #include "src/privet/openssl_utils.h"
 #include "src/string_utils.h"

 extern "C" {
 #include "third_party/libuweave/src/macaroon.h"
 }

 namespace weave {
 namespace privet {

 namespace {

 const char kTokenDelimeter[] = ":";
 const size_t kCaveatBuffetSize = 32;
 const size_t kMaxMacaroonSize = 1024;
 const size_t kMaxPendingClaims = 10;

 template <class T>
 void AppendToArray(T value, std::vector<uint8_t>* array) {
   auto begin = reinterpret_cast<const uint8_t*>(&value);
   array->insert(array->end(), begin, begin + sizeof(value));
 }

 // Returns "scope:time:id".
 std::string CreateTokenData(const UserInfo& user_info, const base::Time& time) {
   return base::IntToString(static_cast<int>(user_info.scope())) +
          kTokenDelimeter + std::to_string(time.ToTimeT()) + kTokenDelimeter +
          user_info.user_id();
 }

 // Splits string of "scope:time:id" format.
 UserInfo SplitTokenData(const std::string& token, base::Time* time) {
   const UserInfo kNone;
   auto parts = SplitAtFirst(token, kTokenDelimeter, false);
   if (parts.second.empty())
     return kNone;
   int scope = 0;
   if (!base::StringToInt(parts.first, &scope) ||
       scope < static_cast<int>(AuthScope::kNone) ||
       scope > static_cast<int>(AuthScope::kOwner)) {
     return kNone;
   }

   parts = SplitAtFirst(parts.second, kTokenDelimeter, false);
   int64_t timestamp{0};
   if (parts.second.empty() || !base::StringToInt64(parts.first, &timestamp))
     return kNone;

   if (time)
     *time = base::Time::FromTimeT(timestamp);
   return UserInfo{static_cast<AuthScope>(scope), parts.second};
 }

 class Caveat {
  public:
   Caveat(UwMacaroonCaveatType type, uint32_t value) {
     CHECK(uw_macaroon_caveat_create_with_uint_(type, value, buffer,
                                                sizeof(buffer), &caveat));
   }

   const UwMacaroonCaveat& GetCaveat() const { return caveat; }

  private:
   UwMacaroonCaveat caveat;
   uint8_t buffer[kCaveatBuffetSize];

   DISALLOW_COPY_AND_ASSIGN(Caveat);
 };

 std::vector<uint8_t> CreateSecret() {
   std::vector<uint8_t> secret(kSha256OutputSize);
   base::RandBytes(secret.data(), secret.size());
   return secret;
 }

 bool IsClaimAllowed(RootClientTokenOwner curret, RootClientTokenOwner claimer) {
   return claimer > curret || claimer == RootClientTokenOwner::kCloud;
 }

 }  // namespace

 AuthManager::AuthManager(Config* config,
                          const std::vector<uint8_t>& certificate_fingerprint)
     : config_{config},
       certificate_fingerprint_{certificate_fingerprint},
       access_secret_{CreateSecret()} {
   if (config_) {
     SetAuthSecret(config_->GetSettings().secret,
                   config_->GetSettings().root_client_token_owner);
   } else {
     SetAuthSecret({}, RootClientTokenOwner::kNone);
   }
 }

 AuthManager::AuthManager(const std::vector<uint8_t>& auth_secret,
                          const std::vector<uint8_t>& certificate_fingerprint,
                          const std::vector<uint8_t>& access_secret,
                          base::Clock* clock)
     : AuthManager(nullptr, certificate_fingerprint) {
   access_secret_ = access_secret.size() == kSha256OutputSize ? access_secret
                                                              : CreateSecret();
   SetAuthSecret(auth_secret, RootClientTokenOwner::kNone);
   if (clock)
     clock_ = clock;
 }

 void AuthManager::SetAuthSecret(const std::vector<uint8_t>& secret,
                                 RootClientTokenOwner owner) {
   auth_secret_ = secret;

   if (auth_secret_.size() != kSha256OutputSize) {
     auth_secret_ = CreateSecret();
     owner = RootClientTokenOwner::kNone;
   }

   if (!config_ || (config_->GetSettings().secret == auth_secret_ &&
                    config_->GetSettings().root_client_token_owner == owner)) {
     return;
   }

   Config::Transaction change{config_};
   change.set_secret(secret);
   change.set_root_client_token_owner(owner);
   change.Commit();
 }

 AuthManager::~AuthManager() {}

 // Returns "[hmac]scope:expiration_time:id".
 std::vector<uint8_t> AuthManager::CreateAccessToken(const UserInfo& user_info,
                                                     base::TimeDelta ttl) const {
   std::string data_str{CreateTokenData(user_info, Now() + ttl)};
   std::vector<uint8_t> data{data_str.begin(), data_str.end()};
   std::vector<uint8_t> hash{HmacSha256(access_secret_, data)};
   hash.insert(hash.end(), data.begin(), data.end());
   return hash;
 }

 // TODO(vitalybuka): Switch to Macaroon?
 // Parses "base64([hmac]scope:id:expriration_time)".
 bool AuthManager::ParseAccessToken(const std::vector<uint8_t>& token,
                                    UserInfo* user_info,
                                    ErrorPtr* error) const {
   if (token.size() <= kSha256OutputSize) {
     Error::AddToPrintf(error, FROM_HERE, errors::kDomain,
                        errors::kInvalidAuthorization, "Invalid token size: %zu",
                        token.size());
     return false;
   }
   std::vector<uint8_t> hash(token.begin(), token.begin() + kSha256OutputSize);
   std::vector<uint8_t> data(token.begin() + kSha256OutputSize, token.end());
   if (hash != HmacSha256(access_secret_, data)) {
     Error::AddTo(error, FROM_HERE, errors::kDomain,
                  errors::kInvalidAuthorization, "Invalid signature");
     return false;
   }

   base::Time time;
   UserInfo info = SplitTokenData(std::string(data.begin(), data.end()), &time);
   if (info.scope() == AuthScope::kNone) {
     Error::AddTo(error, FROM_HERE, errors::kDomain,
                  errors::kInvalidAuthorization, "Invalid token data");
     return false;
   }

   if (time < clock_->Now()) {
     Error::AddTo(error, FROM_HERE, errors::kDomain,
                  errors::kAuthorizationExpired, "Token is expired");
     return false;
   }

   if (user_info)
     *user_info = info;

   return true;
 }

 std::vector<uint8_t> AuthManager::ClaimRootClientAuthToken(
     RootClientTokenOwner owner,
     ErrorPtr* error) {
   CHECK(RootClientTokenOwner::kNone != owner);
   if (config_) {
     auto current = config_->GetSettings().root_client_token_owner;
     if (!IsClaimAllowed(current, owner)) {
       Error::AddToPrintf(
           error, FROM_HERE, errors::kDomain, errors::kAlreadyClaimed,
           "Device already claimed by '%s'", EnumToString(current).c_str());
       return {};
     }
   };

   pending_claims_.push_back(std::make_pair(
       std::unique_ptr<AuthManager>{new AuthManager{nullptr, {}}}, owner));
   if (pending_claims_.size() > kMaxPendingClaims)
     pending_claims_.pop_front();
   return pending_claims_.back().first->GetRootClientAuthToken();
 }

 bool AuthManager::ConfirmClientAuthToken(const std::vector<uint8_t>& token,
                                          ErrorPtr* error) {
   // Cover case when caller sent confirm twice.
   if (pending_claims_.empty() && IsValidAuthToken(token))
     return true;

   auto claim =
       std::find_if(pending_claims_.begin(), pending_claims_.end(),
                    [&token](const decltype(pending_claims_)::value_type& auth) {
                      return auth.first->IsValidAuthToken(token);
                    });
   if (claim == pending_claims_.end()) {
     Error::AddTo(error, FROM_HERE, errors::kDomain, errors::kNotFound,
                  "Unknown claim");
     return false;
   }

   SetAuthSecret(claim->first->GetAuthSecret(), claim->second);
   pending_claims_.clear();
   return true;
 }

 std::vector<uint8_t> AuthManager::GetRootClientAuthToken() const {
   Caveat scope{kUwMacaroonCaveatTypeScope, kUwMacaroonCaveatScopeTypeOwner};
   Caveat issued{kUwMacaroonCaveatTypeIssued,
                 static_cast<uint32_t>(Now().ToTimeT())};

   UwMacaroonCaveat caveats[] = {
       scope.GetCaveat(), issued.GetCaveat(),
   };

   CHECK_EQ(kSha256OutputSize, auth_secret_.size());
   UwMacaroon macaroon{};
   CHECK(uw_macaroon_new_from_root_key_(&macaroon, auth_secret_.data(),
                                        auth_secret_.size(), caveats,
                                        arraysize(caveats)));

   std::vector<uint8_t> token(kMaxMacaroonSize);
   size_t len = 0;
   CHECK(uw_macaroon_dump_(&macaroon, token.data(), token.size(), &len));
   token.resize(len);
   return token;
 }

 base::Time AuthManager::Now() const {
   return clock_->Now();
 }

 bool AuthManager::IsValidAuthToken(const std::vector<uint8_t>& token) const {
   std::vector<uint8_t> buffer(kMaxMacaroonSize);
   UwMacaroon macaroon{};
   if (!uw_macaroon_load_(token.data(), token.size(), buffer.data(),
                          buffer.size(), &macaroon)) {
     return false;
   }

   CHECK_EQ(kSha256OutputSize, auth_secret_.size());
   return uw_macaroon_verify_(&macaroon, auth_secret_.data(),
                              auth_secret_.size());
 }

 std::vector<uint8_t> AuthManager::CreateSessionId() {
   std::vector<uint8_t> result;
   AppendToArray(Now().ToTimeT(), &result);
   AppendToArray(++session_counter_, &result);
   return result;
 }

 bool AuthManager::IsAnonymousAuthSupported() const {
   return !config_ ||
          config_->GetSettings().local_anonymous_access_role != AuthScope::kNone;
 }

 bool AuthManager::IsPairingAuthSupported() const {
   return !config_ || config_->GetSettings().local_pairing_enabled;
 }

 bool AuthManager::IsLocalAuthSupported() const {
   return !config_ ||
          config_->GetSettings().root_client_token_owner !=
              RootClientTokenOwner::kNone;
 }

 }  // namespace privet
 }  // namespace weave
	// Copyright 2015 The Weave 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 "src/privet/auth_manager.h"

	#include <base/rand_util.h>
	#include <base/strings/string_number_conversions.h>

	#include "src/config.h"
	#include "src/data_encoding.h"
	#include "src/privet/constants.h"
	#include "src/privet/openssl_utils.h"
	#include "src/string_utils.h"

	extern "C" {
	#include "third_party/libuweave/src/macaroon.h"
	}

	namespace weave {
	namespace privet {

	namespace {

	const char kTokenDelimeter[] = ":";
	const size_t kCaveatBuffetSize = 32;
	const size_t kMaxMacaroonSize = 1024;
	const size_t kMaxPendingClaims = 10;

	template <class T>
	void AppendToArray(T value, std::vector<uint8_t>* array) {
	auto begin = reinterpret_cast<const uint8_t*>(&value);
	array->insert(array->end(), begin, begin + sizeof(value));
	}

	// Returns "scope:time:id".
	std::string CreateTokenData(const UserInfo& user_info, const base::Time& time) {
	return base::IntToString(static_cast<int>(user_info.scope())) +
	kTokenDelimeter + std::to_string(time.ToTimeT()) + kTokenDelimeter +
	user_info.user_id();
	}

	// Splits string of "scope:time:id" format.
	UserInfo SplitTokenData(const std::string& token, base::Time* time) {
	const UserInfo kNone;
	auto parts = SplitAtFirst(token, kTokenDelimeter, false);
	if (parts.second.empty())
	return kNone;
	int scope = 0;
	if (!base::StringToInt(parts.first, &scope) \|\|
	scope < static_cast<int>(AuthScope::kNone) \|\|
	scope > static_cast<int>(AuthScope::kOwner)) {
	return kNone;
	}

	parts = SplitAtFirst(parts.second, kTokenDelimeter, false);
	int64_t timestamp{0};
	if (parts.second.empty() \|\| !base::StringToInt64(parts.first, &timestamp))
	return kNone;

	if (time)
	*time = base::Time::FromTimeT(timestamp);
	return UserInfo{static_cast<AuthScope>(scope), parts.second};
	}

	class Caveat {
	public:
	Caveat(UwMacaroonCaveatType type, uint32_t value) {
	CHECK(uw_macaroon_caveat_create_with_uint_(type, value, buffer,
	sizeof(buffer), &caveat));
	}

	const UwMacaroonCaveat& GetCaveat() const { return caveat; }

	private:
	UwMacaroonCaveat caveat;
	uint8_t buffer[kCaveatBuffetSize];

	DISALLOW_COPY_AND_ASSIGN(Caveat);
	};

	std::vector<uint8_t> CreateSecret() {
	std::vector<uint8_t> secret(kSha256OutputSize);
	base::RandBytes(secret.data(), secret.size());
	return secret;
	}

	bool IsClaimAllowed(RootClientTokenOwner curret, RootClientTokenOwner claimer) {
	return claimer > curret \|\| claimer == RootClientTokenOwner::kCloud;
	}

	} // namespace

	AuthManager::AuthManager(Config* config,
	const std::vector<uint8_t>& certificate_fingerprint)
	: config_{config},
	certificate_fingerprint_{certificate_fingerprint},
	access_secret_{CreateSecret()} {
	if (config_) {
	SetAuthSecret(config_->GetSettings().secret,
	config_->GetSettings().root_client_token_owner);
	} else {
	SetAuthSecret({}, RootClientTokenOwner::kNone);
	}
	}

	AuthManager::AuthManager(const std::vector<uint8_t>& auth_secret,
	const std::vector<uint8_t>& certificate_fingerprint,
	const std::vector<uint8_t>& access_secret,
	base::Clock* clock)
	: AuthManager(nullptr, certificate_fingerprint) {
	access_secret_ = access_secret.size() == kSha256OutputSize ? access_secret
	: CreateSecret();
	SetAuthSecret(auth_secret, RootClientTokenOwner::kNone);
	if (clock)
	clock_ = clock;
	}

	void AuthManager::SetAuthSecret(const std::vector<uint8_t>& secret,
	RootClientTokenOwner owner) {
	auth_secret_ = secret;

	if (auth_secret_.size() != kSha256OutputSize) {
	auth_secret_ = CreateSecret();
	owner = RootClientTokenOwner::kNone;
	}

	if (!config_ \|\| (config_->GetSettings().secret == auth_secret_ &&
	config_->GetSettings().root_client_token_owner == owner)) {
	return;
	}

	Config::Transaction change{config_};
	change.set_secret(secret);
	change.set_root_client_token_owner(owner);
	change.Commit();
	}

	AuthManager::~AuthManager() {}

	// Returns "[hmac]scope:expiration_time:id".
	std::vector<uint8_t> AuthManager::CreateAccessToken(const UserInfo& user_info,
	base::TimeDelta ttl) const {
	std::string data_str{CreateTokenData(user_info, Now() + ttl)};
	std::vector<uint8_t> data{data_str.begin(), data_str.end()};
	std::vector<uint8_t> hash{HmacSha256(access_secret_, data)};
	hash.insert(hash.end(), data.begin(), data.end());
	return hash;
	}

	// TODO(vitalybuka): Switch to Macaroon?
	// Parses "base64([hmac]scope:id:expriration_time)".
	bool AuthManager::ParseAccessToken(const std::vector<uint8_t>& token,
	UserInfo* user_info,
	ErrorPtr* error) const {
	if (token.size() <= kSha256OutputSize) {
	Error::AddToPrintf(error, FROM_HERE, errors::kDomain,
	errors::kInvalidAuthorization, "Invalid token size: %zu",
	token.size());
	return false;
	}
	std::vector<uint8_t> hash(token.begin(), token.begin() + kSha256OutputSize);
	std::vector<uint8_t> data(token.begin() + kSha256OutputSize, token.end());
	if (hash != HmacSha256(access_secret_, data)) {
	Error::AddTo(error, FROM_HERE, errors::kDomain,
	errors::kInvalidAuthorization, "Invalid signature");
	return false;
	}

	base::Time time;
	UserInfo info = SplitTokenData(std::string(data.begin(), data.end()), &time);
	if (info.scope() == AuthScope::kNone) {
	Error::AddTo(error, FROM_HERE, errors::kDomain,
	errors::kInvalidAuthorization, "Invalid token data");
	return false;
	}

	if (time < clock_->Now()) {
	Error::AddTo(error, FROM_HERE, errors::kDomain,
	errors::kAuthorizationExpired, "Token is expired");
	return false;
	}

	if (user_info)
	*user_info = info;

	return true;
	}

	std::vector<uint8_t> AuthManager::ClaimRootClientAuthToken(
	RootClientTokenOwner owner,
	ErrorPtr* error) {
	CHECK(RootClientTokenOwner::kNone != owner);
	if (config_) {
	auto current = config_->GetSettings().root_client_token_owner;
	if (!IsClaimAllowed(current, owner)) {
	Error::AddToPrintf(
	error, FROM_HERE, errors::kDomain, errors::kAlreadyClaimed,
	"Device already claimed by '%s'", EnumToString(current).c_str());
	return {};
	}
	};

	pending_claims_.push_back(std::make_pair(
	std::unique_ptr<AuthManager>{new AuthManager{nullptr, {}}}, owner));
	if (pending_claims_.size() > kMaxPendingClaims)
	pending_claims_.pop_front();
	return pending_claims_.back().first->GetRootClientAuthToken();
	}

	bool AuthManager::ConfirmClientAuthToken(const std::vector<uint8_t>& token,
	ErrorPtr* error) {
	// Cover case when caller sent confirm twice.
	if (pending_claims_.empty() && IsValidAuthToken(token))
	return true;

	auto claim =
	std::find_if(pending_claims_.begin(), pending_claims_.end(),
	[&token](const decltype(pending_claims_)::value_type& auth) {
	return auth.first->IsValidAuthToken(token);
	});
	if (claim == pending_claims_.end()) {
	Error::AddTo(error, FROM_HERE, errors::kDomain, errors::kNotFound,
	"Unknown claim");
	return false;
	}

	SetAuthSecret(claim->first->GetAuthSecret(), claim->second);
	pending_claims_.clear();
	return true;
	}

	std::vector<uint8_t> AuthManager::GetRootClientAuthToken() const {
	Caveat scope{kUwMacaroonCaveatTypeScope, kUwMacaroonCaveatScopeTypeOwner};
	Caveat issued{kUwMacaroonCaveatTypeIssued,
	static_cast<uint32_t>(Now().ToTimeT())};

	UwMacaroonCaveat caveats[] = {
	scope.GetCaveat(), issued.GetCaveat(),
	};

	CHECK_EQ(kSha256OutputSize, auth_secret_.size());
	UwMacaroon macaroon{};
	CHECK(uw_macaroon_new_from_root_key_(&macaroon, auth_secret_.data(),
	auth_secret_.size(), caveats,
	arraysize(caveats)));

	std::vector<uint8_t> token(kMaxMacaroonSize);
	size_t len = 0;
	CHECK(uw_macaroon_dump_(&macaroon, token.data(), token.size(), &len));
	token.resize(len);
	return token;
	}

	base::Time AuthManager::Now() const {
	return clock_->Now();
	}

	bool AuthManager::IsValidAuthToken(const std::vector<uint8_t>& token) const {
	std::vector<uint8_t> buffer(kMaxMacaroonSize);
	UwMacaroon macaroon{};
	if (!uw_macaroon_load_(token.data(), token.size(), buffer.data(),
	buffer.size(), &macaroon)) {
	return false;
	}

	CHECK_EQ(kSha256OutputSize, auth_secret_.size());
	return uw_macaroon_verify_(&macaroon, auth_secret_.data(),
	auth_secret_.size());
	}

	std::vector<uint8_t> AuthManager::CreateSessionId() {
	std::vector<uint8_t> result;
	AppendToArray(Now().ToTimeT(), &result);
	AppendToArray(++session_counter_, &result);
	return result;
	}

	bool AuthManager::IsAnonymousAuthSupported() const {
	return !config_ \|\|
	config_->GetSettings().local_anonymous_access_role != AuthScope::kNone;
	}

	bool AuthManager::IsPairingAuthSupported() const {
	return !config_ \|\| config_->GetSettings().local_pairing_enabled;
	}

	bool AuthManager::IsLocalAuthSupported() const {
	return !config_ \|\|
	config_->GetSettings().root_client_token_owner !=
	RootClientTokenOwner::kNone;
	}

	} // namespace privet
	} // namespace weave