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// 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/data_encoding.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;
// Returns "scope:id:time".
std::string CreateTokenData(const UserInfo& user_info, const base::Time& time) {
return base::IntToString(static_cast<int>(user_info.scope())) +
kTokenDelimeter + base::Uint64ToString(user_info.user_id()) +
kTokenDelimeter + base::Int64ToString(time.ToTimeT());
}
// Splits string of "scope:id:time" format.
UserInfo SplitTokenData(const std::string& token, base::Time* time) {
const UserInfo kNone;
auto parts = Split(token, kTokenDelimeter, false, false);
if (parts.size() != 3)
return kNone;
int scope = 0;
if (!base::StringToInt(parts[0], &scope) ||
scope < static_cast<int>(AuthScope::kNone) ||
scope > static_cast<int>(AuthScope::kOwner)) {
return kNone;
}
uint64_t id{0};
if (!base::StringToUint64(parts[1], &id))
return kNone;
int64_t timestamp{0};
if (!base::StringToInt64(parts[2], ×tamp))
return kNone;
*time = base::Time::FromTimeT(timestamp);
return UserInfo{static_cast<AuthScope>(scope), id};
}
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);
};
} // namespace
AuthManager::AuthManager(const std::vector<uint8_t>& secret,
const std::vector<uint8_t>& certificate_fingerprint,
base::Clock* clock)
: clock_{clock ? clock : &default_clock_},
secret_{secret},
certificate_fingerprint_{certificate_fingerprint} {
if (secret_.size() != kSha256OutputSize) {
secret_.resize(kSha256OutputSize);
base::RandBytes(secret_.data(), secret_.size());
}
}
AuthManager::~AuthManager() {}
// Returns "[hmac]scope:id:time".
std::vector<uint8_t> AuthManager::CreateAccessToken(const UserInfo& user_info) {
std::string data_str{CreateTokenData(user_info, Now())};
std::vector<uint8_t> data{data_str.begin(), data_str.end()};
std::vector<uint8_t> hash{HmacSha256(secret_, data)};
hash.insert(hash.end(), data.begin(), data.end());
return hash;
}
// Parses "base64([hmac]scope:id:time)".
UserInfo AuthManager::ParseAccessToken(const std::vector<uint8_t>& token,
base::Time* time) const {
if (token.size() <= kSha256OutputSize)
return UserInfo{};
std::vector<uint8_t> hash(token.begin(), token.begin() + kSha256OutputSize);
std::vector<uint8_t> data(token.begin() + kSha256OutputSize, token.end());
if (hash != HmacSha256(secret_, data))
return UserInfo{};
return SplitTokenData(std::string(data.begin(), data.end()), time);
}
std::vector<uint8_t> AuthManager::GetRootDeviceToken() const {
Caveat scope{kUwMacaroonCaveatTypeScope, kUwMacaroonCaveatScopeTypeOwner};
Caveat issued{kUwMacaroonCaveatTypeIssued,
static_cast<uint32_t>(Now().ToTimeT())};
UwMacaroonCaveat caveats[] = {
scope.GetCaveat(), issued.GetCaveat(),
};
UwMacaroon macaroon{};
CHECK(uw_macaroon_new_from_root_key_(
&macaroon, secret_.data(), 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();
}
} // namespace privet
} // namespace weave
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