1 /*
2 * Copyright 2018 Google LLC
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "fcp/secagg/client/secagg_client_r1_share_keys_input_set_state.h"
18
19 #include <cstdint>
20 #include <string>
21 #include <utility>
22
23 #include "fcp/base/monitoring.h"
24 #include "fcp/secagg/client/other_client_state.h"
25 #include "fcp/secagg/client/secagg_client_aborted_state.h"
26 #include "fcp/secagg/client/secagg_client_completed_state.h"
27 #include "fcp/secagg/client/secagg_client_r2_masked_input_coll_input_set_state.h"
28 #include "fcp/secagg/client/secagg_client_state.h"
29 #include "fcp/secagg/client/send_to_server_interface.h"
30 #include "fcp/secagg/client/state_transition_listener_interface.h"
31 #include "fcp/secagg/shared/aes_prng_factory.h"
32 #include "fcp/secagg/shared/ecdh_key_agreement.h"
33 #include "fcp/secagg/shared/input_vector_specification.h"
34 #include "fcp/secagg/shared/secagg_vector.h"
35 #include "fcp/secagg/shared/shamir_secret_sharing.h"
36
37 namespace fcp {
38 namespace secagg {
SecAggClientR1ShareKeysInputSetState(uint32_t max_neighbors_expected,uint32_t minimum_surviving_neighbors_for_reconstruction,std::unique_ptr<EcdhKeyAgreement> enc_key_agreement,std::unique_ptr<SecAggVectorMap> input_map,std::unique_ptr<std::vector<InputVectorSpecification>> input_vector_specs,std::unique_ptr<SecurePrng> prng,std::unique_ptr<EcdhKeyAgreement> prng_key_agreement,std::unique_ptr<SendToServerInterface> sender,std::unique_ptr<StateTransitionListenerInterface> transition_listener,std::unique_ptr<AesPrngFactory> prng_factory,AsyncAbort * async_abort)39 SecAggClientR1ShareKeysInputSetState::SecAggClientR1ShareKeysInputSetState(
40 uint32_t max_neighbors_expected,
41 uint32_t minimum_surviving_neighbors_for_reconstruction,
42 std::unique_ptr<EcdhKeyAgreement> enc_key_agreement,
43 std::unique_ptr<SecAggVectorMap> input_map,
44 std::unique_ptr<std::vector<InputVectorSpecification> > input_vector_specs,
45 std::unique_ptr<SecurePrng> prng,
46 std::unique_ptr<EcdhKeyAgreement> prng_key_agreement,
47 std::unique_ptr<SendToServerInterface> sender,
48 std::unique_ptr<StateTransitionListenerInterface> transition_listener,
49 std::unique_ptr<AesPrngFactory> prng_factory, AsyncAbort* async_abort)
50 : SecAggClientR1ShareKeysBaseState(
51 std::move(sender), std::move(transition_listener), async_abort),
52 max_neighbors_expected_(max_neighbors_expected),
53 minimum_surviving_neighbors_for_reconstruction_(
54 minimum_surviving_neighbors_for_reconstruction),
55 enc_key_agreement_(std::move(enc_key_agreement)),
56 input_map_(std::move(input_map)),
57 input_vector_specs_(std::move(input_vector_specs)),
58 prng_(std::move(prng)),
59 prng_key_agreement_(std::move(prng_key_agreement)),
60 prng_factory_(std::move(prng_factory)) {}
61
62 StatusOr<std::unique_ptr<SecAggClientState> >
HandleMessage(const ServerToClientWrapperMessage & message)63 SecAggClientR1ShareKeysInputSetState::HandleMessage(
64 const ServerToClientWrapperMessage& message) {
65 // Handle abort messages or share keys requests only.
66 if (message.has_abort()) {
67 if (message.abort().early_success()) {
68 return {std::make_unique<SecAggClientCompletedState>(
69 std::move(sender_), std::move(transition_listener_))};
70 } else {
71 return {std::make_unique<SecAggClientAbortedState>(
72 "Aborting because of abort message from the server.",
73 std::move(sender_), std::move(transition_listener_))};
74 }
75 } else if (!message.has_share_keys_request()) {
76 // Returns an error indicating that the message is of invalid type.
77 return SecAggClientState::HandleMessage(message);
78 }
79 uint32_t client_id;
80 uint32_t number_of_alive_clients;
81 uint32_t number_of_clients;
82 std::string error_message;
83 auto other_client_enc_keys = std::make_unique<std::vector<AesKey> >();
84 auto other_client_prng_keys = std::make_unique<std::vector<AesKey> >();
85 auto other_client_states = std::make_unique<std::vector<OtherClientState> >();
86 auto own_self_key_share = std::make_unique<ShamirShare>();
87 auto session_id = std::make_unique<SessionId>();
88
89 uint8_t self_prng_key_buffer[AesKey::kSize];
90 for (uint8_t& i : self_prng_key_buffer) {
91 i = prng_->Rand8();
92 }
93 auto self_prng_key = std::make_unique<AesKey>(self_prng_key_buffer);
94
95 bool success = HandleShareKeysRequest(
96 message.share_keys_request(), *enc_key_agreement_,
97 max_neighbors_expected_, minimum_surviving_neighbors_for_reconstruction_,
98 *prng_key_agreement_, *self_prng_key, prng_.get(), &client_id,
99 &error_message, &number_of_alive_clients, &number_of_clients,
100 other_client_enc_keys.get(), other_client_prng_keys.get(),
101 other_client_states.get(), &self_prng_key_shares_,
102 &pairwise_prng_key_shares_, session_id.get());
103
104 if (!success) {
105 return AbortAndNotifyServer(error_message);
106 }
107
108 if (async_abort_ && async_abort_->Signalled()) {
109 return AbortAndNotifyServer(async_abort_->Message());
110 }
111
112 if (!EncryptAndSendResponse(*other_client_enc_keys, pairwise_prng_key_shares_,
113 self_prng_key_shares_, sender_.get())) {
114 return AbortAndNotifyServer(async_abort_->Message());
115 }
116
117 *own_self_key_share = self_prng_key_shares_[client_id];
118 return {std::make_unique<SecAggClientR2MaskedInputCollInputSetState>(
119 client_id, minimum_surviving_neighbors_for_reconstruction_,
120 number_of_alive_clients, number_of_clients, std::move(input_map_),
121 std::move(input_vector_specs_), std::move(other_client_states),
122 std::move(other_client_enc_keys), std::move(other_client_prng_keys),
123 std::move(own_self_key_share), std::move(self_prng_key),
124 std::move(sender_), std::move(transition_listener_),
125 std::move(session_id), std::move(prng_factory_), async_abort_)};
126 }
127
StateName() const128 std::string SecAggClientR1ShareKeysInputSetState::StateName() const {
129 return "R1_SHARE_KEYS_INPUT_SET";
130 }
131
132 } // namespace secagg
133 } // namespace fcp
134