feat(1090): validate that some arrays are zero-padded on the right (#…

…2519)

Resolves #1090 

- Added a validation check for arrays to be zero-padded in
utils::array.hpp
- Activate this validation check in native private init and inner kernel
circuit on the following private_circuit_public_input members:
    - read_requests
    - return_values
    - new_commitments
    - new_nullifiers
    - nullified_commitments
    - private_call_stack
    - public_call_stack
    - new_l2_to_l1_msgs
- Unit tests on the validation routine and native private kernel
circuits

circuits/cpp/src/aztec3/circuits/kernel/private/common.cpp

@@ -7,6 +7,7 @@
 #include "aztec3/circuits/abis/function_data.hpp"
 #include "aztec3/circuits/abis/kernel_circuit_public_inputs.hpp"
 #include "aztec3/circuits/abis/new_contract_data.hpp"
+#include "aztec3/circuits/abis/private_circuit_public_inputs.hpp"
 #include "aztec3/circuits/abis/private_kernel/private_call_data.hpp"
 #include "aztec3/circuits/abis/read_request_membership_witness.hpp"
 #include "aztec3/circuits/hash.hpp"
@@ -16,6 +17,7 @@
 
 using DummyBuilder = aztec3::utils::DummyCircuitBuilder;
 
+using aztec3::circuits::abis::CompleteAddress;
 using aztec3::circuits::abis::ContractDeploymentData;
 using aztec3::circuits::abis::ContractLeafPreimage;
 using aztec3::circuits::abis::FunctionData;
@@ -26,6 +28,7 @@ using aztec3::circuits::abis::ReadRequestMembershipWitness;
 using aztec3::utils::array_push;
 using aztec3::utils::is_array_empty;
 using aztec3::utils::push_array_to_array;
+using aztec3::utils::validate_array;
 using DummyBuilder = aztec3::utils::DummyCircuitBuilder;
 using CircuitErrorCode = aztec3::utils::CircuitErrorCode;
 using aztec3::circuits::abis::private_kernel::PrivateCallData;
@@ -114,6 +117,28 @@ void common_validate_read_requests(DummyBuilder& builder,
     }
 }
 
+/**
+ * @brief We validate that relevant arrays assumed to be zero-padded on the right comply to this format.
+ *
+ * @param builder
+ * @param app_public_inputs Reference to the private_circuit_public_inputs of the current kernel iteration.
+ */
+void common_validate_arrays(DummyBuilder& builder, PrivateCircuitPublicInputs<NT> const& app_public_inputs)
+{
+    // Each of the following arrays is expected to be zero-padded.
+    // In addition, some of the following arrays (new_commitments, etc...) are passed
+    // to push_array_to_array() routines which rely on the passed arrays to be well-formed.
+    validate_array(builder, app_public_inputs.return_values, "Return values");
+    validate_array(builder, app_public_inputs.read_requests, "Read requests");
+    validate_array(builder, app_public_inputs.new_commitments, "New commitments");
+    validate_array(builder, app_public_inputs.new_nullifiers, "New nullifiers");
+    validate_array(builder, app_public_inputs.nullified_commitments, "Nullified commitments");
+    validate_array(builder, app_public_inputs.private_call_stack, "Private Call Stack");
+    validate_array(builder, app_public_inputs.public_call_stack, "Public Call Stack");
+    validate_array(builder, app_public_inputs.new_l2_to_l1_msgs, "New L2 to L1 messages");
+    // encrypted_logs_hash and unencrypted_logs_hash have their own integrity checks.
+}
+
 void common_validate_0th_nullifier(DummyBuilder& builder, CombinedAccumulatedData<NT> const& end)
 {
     builder.do_assert(end.new_nullifiers[0] != 0,
@@ -296,10 +321,10 @@ void common_contract_logic(DummyBuilder& builder,
         auto constructor_hash =
             compute_constructor_hash(function_data, private_call_public_inputs.args_hash, private_call_vk_hash);
 
-        auto const new_contract_address = abis::CompleteAddress<NT>::compute(contract_dep_data.deployer_public_key,
-                                                                             contract_dep_data.contract_address_salt,
-                                                                             contract_dep_data.function_tree_root,
-                                                                             constructor_hash)
+        auto const new_contract_address = CompleteAddress<NT>::compute(contract_dep_data.deployer_public_key,
+                                                                       contract_dep_data.contract_address_salt,
+                                                                       contract_dep_data.function_tree_root,
+                                                                       constructor_hash)
                                               .address;
 
         // Add new contract data if its a contract deployment function

circuits/cpp/src/aztec3/circuits/kernel/private/common.hpp

@@ -7,6 +7,7 @@
 #include "aztec3/circuits/abis/function_data.hpp"
 #include "aztec3/circuits/abis/kernel_circuit_public_inputs.hpp"
 #include "aztec3/circuits/abis/previous_kernel_data.hpp"
+#include "aztec3/circuits/abis/private_circuit_public_inputs.hpp"
 #include "aztec3/circuits/abis/private_kernel/private_call_data.hpp"
 #include "aztec3/circuits/abis/read_request_membership_witness.hpp"
 #include "aztec3/utils/dummy_circuit_builder.hpp"
@@ -19,6 +20,7 @@ using aztec3::circuits::abis::ContractDeploymentData;
 using aztec3::circuits::abis::FunctionData;
 using aztec3::circuits::abis::KernelCircuitPublicInputs;
 using aztec3::circuits::abis::PreviousKernelData;
+using aztec3::circuits::abis::PrivateCircuitPublicInputs;
 using aztec3::circuits::abis::ReadRequestMembershipWitness;
 using aztec3::circuits::abis::private_kernel::PrivateCallData;
 
@@ -34,6 +36,7 @@ void common_validate_read_requests(DummyBuilder& builder,
                                    std::array<ReadRequestMembershipWitness<NT, PRIVATE_DATA_TREE_HEIGHT>,
                                               MAX_READ_REQUESTS_PER_CALL> const& read_request_membership_witnesses);
 
+void common_validate_arrays(DummyBuilder& builder, PrivateCircuitPublicInputs<NT> const& app_public_inputs);
 void common_validate_0th_nullifier(DummyBuilder& builder, CombinedAccumulatedData<NT> const& end);
 
 void common_update_end_values(DummyBuilder& builder,

circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit_init.cpp

@@ -160,6 +160,8 @@ KernelCircuitPublicInputs<NT> native_private_kernel_circuit_initial(DummyCircuit
 
     validate_inputs(builder, private_inputs);
 
+    common_validate_arrays(builder, private_inputs.private_call.call_stack_item.public_inputs);
+
     validate_this_private_call_against_tx_request(builder, private_inputs);
 
     common_validate_call_stack(builder, private_inputs.private_call);

circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit_init.test.cpp

@@ -117,6 +117,123 @@ TEST_F(native_private_kernel_init_tests, basic_contract_deployment)
     EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::NO_ERROR);
 }
 
+TEST_F(native_private_kernel_init_tests, input_validation_malformed_arrays_return_values)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_init(true, constructor, standard_test_args());
+
+    std::array<fr, RETURN_VALUES_LENGTH> malformed_return_values{ fr(0), fr(0), fr(553) };
+    private_inputs.private_call.call_stack_item.public_inputs.return_values = malformed_return_values;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_return_values");
+    native_private_kernel_circuit_initial(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_init_tests, input_validation_malformed_arrays_read_requests)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_init(true, constructor, standard_test_args());
+
+    std::array<fr, MAX_READ_REQUESTS_PER_CALL> malformed_read_requests{ fr(0), fr(9123), fr(0), fr(12) };
+    private_inputs.private_call.call_stack_item.public_inputs.read_requests = malformed_read_requests;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_read_requests");
+    native_private_kernel_circuit_initial(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_init_tests, input_validation_malformed_arrays_commitments)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_init(true, constructor, standard_test_args());
+
+    std::array<fr, MAX_NEW_COMMITMENTS_PER_CALL> malformed_commitments{ fr(0), fr(9123) };
+    private_inputs.private_call.call_stack_item.public_inputs.new_commitments = malformed_commitments;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_commitments");
+    native_private_kernel_circuit_initial(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_init_tests, input_validation_malformed_arrays_nullifiers)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_init(true, constructor, standard_test_args());
+
+    std::array<fr, MAX_NEW_NULLIFIERS_PER_CALL> malformed_nullifiers{};
+    malformed_nullifiers[MAX_NEW_NULLIFIERS_PER_CALL - 1] = fr(12);
+    private_inputs.private_call.call_stack_item.public_inputs.new_nullifiers = malformed_nullifiers;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_nullifiers");
+    native_private_kernel_circuit_initial(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_init_tests, input_validation_malformed_arrays_nullified_commitments)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_init(true, constructor, standard_test_args());
+
+    std::array<fr, MAX_NEW_NULLIFIERS_PER_CALL> malformed_nullified_commitments{ fr(0),
+                                                                                 fr(0),
+                                                                                 EMPTY_NULLIFIED_COMMITMENT };
+    private_inputs.private_call.call_stack_item.public_inputs.nullified_commitments = malformed_nullified_commitments;
+
+    DummyBuilder builder =
+        DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_nullified_commitments");
+    native_private_kernel_circuit_initial(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_init_tests, input_validation_malformed_arrays_private_call_stack)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_init(true, constructor, standard_test_args());
+
+    std::array<fr, MAX_PRIVATE_CALL_STACK_LENGTH_PER_CALL> malformed_private_call_stack{ fr(0), fr(888) };
+    private_inputs.private_call.call_stack_item.public_inputs.private_call_stack = malformed_private_call_stack;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_private_call_stack");
+    native_private_kernel_circuit_initial(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_init_tests, input_validation_malformed_arrays_public_call_stack)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_init(true, constructor, standard_test_args());
+
+    std::array<fr, MAX_PUBLIC_CALL_STACK_LENGTH_PER_CALL> malformed_public_call_stack{ fr(0), fr(888) };
+    private_inputs.private_call.call_stack_item.public_inputs.public_call_stack = malformed_public_call_stack;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_public_call_stack");
+    native_private_kernel_circuit_initial(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_init_tests, input_validation_malformed_arrays_new_l2_to_l1_msgs)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_init(true, constructor, standard_test_args());
+
+    std::array<fr, MAX_NEW_L2_TO_L1_MSGS_PER_CALL> malformed_new_l2_to_l1_msgs{};
+    malformed_new_l2_to_l1_msgs[MAX_NEW_L2_TO_L1_MSGS_PER_CALL - 1] = fr(1);
+    private_inputs.private_call.call_stack_item.public_inputs.new_l2_to_l1_msgs = malformed_new_l2_to_l1_msgs;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_new_l2_to_l1_msgs");
+    native_private_kernel_circuit_initial(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
 TEST_F(native_private_kernel_init_tests, contract_deployment_call_stack_item_hash_mismatch_fails)
 {
     auto private_inputs = do_private_call_get_kernel_inputs_init(true, constructor, standard_test_args());

circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit_inner.cpp

@@ -106,6 +106,8 @@ KernelCircuitPublicInputs<NT> native_private_kernel_circuit_inner(DummyCircuitBu
 
     validate_inputs(builder, private_inputs);
 
+    common_validate_arrays(builder, private_inputs.private_call.call_stack_item.public_inputs);
+
     pop_and_validate_this_private_call_hash(builder, private_inputs.private_call, public_inputs.end.private_call_stack);
 
     common_validate_call_stack(builder, private_inputs.private_call);

circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit_inner.test.cpp

@@ -206,6 +206,123 @@ TEST_F(native_private_kernel_inner_tests, private_function_incorrect_call_stack_
               CircuitErrorCode::PRIVATE_KERNEL__CALCULATED_PRIVATE_CALL_HASH_AND_PROVIDED_PRIVATE_CALL_HASH_MISMATCH);
 }
 
+TEST_F(native_private_kernel_inner_tests, input_validation_malformed_arrays_return_values)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_inner(false, deposit, standard_test_args());
+
+    std::array<fr, RETURN_VALUES_LENGTH> malformed_return_values{ fr(0), fr(0), fr(553) };
+    private_inputs.private_call.call_stack_item.public_inputs.return_values = malformed_return_values;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_return_values");
+    native_private_kernel_circuit_inner(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_inner_tests, input_validation_malformed_arrays_read_requests)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_inner(false, deposit, standard_test_args());
+
+    std::array<fr, MAX_READ_REQUESTS_PER_CALL> malformed_read_requests{ fr(0), fr(9123), fr(0), fr(12) };
+    private_inputs.private_call.call_stack_item.public_inputs.read_requests = malformed_read_requests;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_read_requests");
+    native_private_kernel_circuit_inner(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_inner_tests, input_validation_malformed_arrays_commitments)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_inner(false, deposit, standard_test_args());
+
+    std::array<fr, MAX_NEW_COMMITMENTS_PER_CALL> malformed_commitments{ fr(0), fr(9123) };
+    private_inputs.private_call.call_stack_item.public_inputs.new_commitments = malformed_commitments;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_commitments");
+    native_private_kernel_circuit_inner(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_inner_tests, input_validation_malformed_arrays_nullifiers)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_inner(false, deposit, standard_test_args());
+
+    std::array<fr, MAX_NEW_NULLIFIERS_PER_CALL> malformed_nullifiers{};
+    malformed_nullifiers[MAX_NEW_NULLIFIERS_PER_CALL - 1] = fr(12);
+    private_inputs.private_call.call_stack_item.public_inputs.new_nullifiers = malformed_nullifiers;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_nullifiers");
+    native_private_kernel_circuit_inner(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_inner_tests, input_validation_malformed_arrays_nullified_commitments)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_inner(false, deposit, standard_test_args());
+
+    std::array<fr, MAX_NEW_NULLIFIERS_PER_CALL> malformed_nullified_commitments{ fr(0),
+                                                                                 fr(0),
+                                                                                 EMPTY_NULLIFIED_COMMITMENT };
+    private_inputs.private_call.call_stack_item.public_inputs.nullified_commitments = malformed_nullified_commitments;
+
+    DummyBuilder builder =
+        DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_nullified_commitments");
+    native_private_kernel_circuit_inner(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_inner_tests, input_validation_malformed_arrays_private_call_stack)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_inner(false, deposit, standard_test_args());
+
+    std::array<fr, MAX_PRIVATE_CALL_STACK_LENGTH_PER_CALL> malformed_private_call_stack{ fr(0), fr(888) };
+    private_inputs.private_call.call_stack_item.public_inputs.private_call_stack = malformed_private_call_stack;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_private_call_stack");
+    native_private_kernel_circuit_inner(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_inner_tests, input_validation_malformed_arrays_public_call_stack)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_inner(false, deposit, standard_test_args());
+
+    std::array<fr, MAX_PUBLIC_CALL_STACK_LENGTH_PER_CALL> malformed_public_call_stack{ fr(0), fr(888) };
+    private_inputs.private_call.call_stack_item.public_inputs.public_call_stack = malformed_public_call_stack;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_public_call_stack");
+    native_private_kernel_circuit_inner(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
+TEST_F(native_private_kernel_inner_tests, input_validation_malformed_arrays_new_l2_to_l1_msgs)
+{
+    auto private_inputs = do_private_call_get_kernel_inputs_inner(false, deposit, standard_test_args());
+
+    std::array<fr, MAX_NEW_L2_TO_L1_MSGS_PER_CALL> malformed_new_l2_to_l1_msgs{};
+    malformed_new_l2_to_l1_msgs[MAX_NEW_L2_TO_L1_MSGS_PER_CALL - 1] = fr(1);
+    private_inputs.private_call.call_stack_item.public_inputs.new_l2_to_l1_msgs = malformed_new_l2_to_l1_msgs;
+
+    DummyBuilder builder = DummyBuilder("private_kernel_tests__input_validation_malformed_arrays_new_l2_to_l1_msgs");
+    native_private_kernel_circuit_inner(builder, private_inputs);
+
+    EXPECT_EQ(builder.failed(), true);
+    EXPECT_EQ(builder.get_first_failure().code, CircuitErrorCode::ARRAY_NOT_ZERO_RIGHT_PADDED);
+}
+
 TEST_F(native_private_kernel_inner_tests, private_kernel_should_fail_if_aggregating_too_many_commitments)
 {
     // Negative test to check if push_array_to_array fails if two many commitments are merged together

circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit_ordering.cpp

@@ -68,10 +68,6 @@ void match_reads_to_commitments(DummyCircuitBuilder& builder,
     }
 }
 
-// TODO(https://github.com/AztecProtocol/aztec-packages/issues/837): optimized based on hints
-// regarding matching a nullifier to a commitment
-// i.e., we get pairs i,j such that new_nullifiers[i] == new_commitments[j]
-
 /**
  * @brief This function matches transient nullifiers to commitments and squashes (deletes) them both.
  *