Line data    Source code

       1              : /*
       2              :  *
       3              :  *    Copyright (c) 2021 Project CHIP Authors
       4              :  *
       5              :  *    Licensed under the Apache License, Version 2.0 (the "License");
       6              :  *    you may not use this file except in compliance with the License.
       7              :  *    You may obtain a copy of the License at
       8              :  *
       9              :  *        http://www.apache.org/licenses/LICENSE-2.0
      10              :  *
      11              :  *    Unless required by applicable law or agreed to in writing, software
      12              :  *    distributed under the License is distributed on an "AS IS" BASIS,
      13              :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      14              :  *    See the License for the specific language governing permissions and
      15              :  *    limitations under the License.
      16              :  */
      17              : 
      18              : /**
      19              :  *    @file
      20              :  *      This file provides a utility to generate Additional Data payload and its members
      21              :  *      (e.g. rotating device id)
      22              :  *
      23              :  */
      24              : 
      25              : #include "AdditionalDataPayloadGenerator.h"
      26              : #include "AdditionalDataPayload.h"
      27              : 
      28              : #include <crypto/CHIPCryptoPAL.h>
      29              : #include <lib/core/CHIPCore.h>
      30              : #include <lib/core/CHIPEncoding.h>
      31              : #include <lib/core/CHIPSafeCasts.h>
      32              : #include <lib/core/TLV.h>
      33              : #include <lib/support/BufferWriter.h>
      34              : #include <lib/support/BytesToHex.h>
      35              : #include <lib/support/CHIPMem.h>
      36              : #include <stdlib.h>
      37              : 
      38              : using namespace chip;
      39              : using namespace chip::System;
      40              : using namespace chip::TLV;
      41              : using namespace chip::Crypto;
      42              : using namespace chip::SetupPayloadData;
      43              : using namespace chip::Encoding::LittleEndian;
      44              : 
      45              : using chip::Encoding::BytesToUppercaseHexString;
      46              : 
      47              : CHIP_ERROR
      48            1 : AdditionalDataPayloadGenerator::generateAdditionalDataPayload(AdditionalDataPayloadGeneratorParams & params,
      49              :                                                               PacketBufferHandle & bufferHandle,
      50              :                                                               BitFlags<AdditionalDataFields> additionalDataFields)
      51              : {
      52            1 :     System::PacketBufferTLVWriter writer;
      53            1 :     TLVWriter innerWriter;
      54              : 
      55              :     // Initialize TLVWriter
      56            1 :     auto tempBuffer = chip::System::PacketBufferHandle::New(chip::System::PacketBuffer::kMaxSize);
      57            1 :     VerifyOrReturnError(!tempBuffer.IsNull(), CHIP_ERROR_NO_MEMORY);
      58            1 :     writer.Init(std::move(tempBuffer));
      59              : 
      60            1 :     ReturnErrorOnFailure(writer.OpenContainer(AnonymousTag(), kTLVType_Structure, innerWriter));
      61              : 
      62              : #if CHIP_ENABLE_ROTATING_DEVICE_ID
      63              :     if (additionalDataFields.Has(AdditionalDataFields::RotatingDeviceId))
      64              :     {
      65              :         uint8_t rotatingDeviceIdInternalBuffer[RotatingDeviceId::kMaxLength];
      66              :         MutableByteSpan rotatingDeviceIdBuffer(rotatingDeviceIdInternalBuffer);
      67              : 
      68              :         // Generating Device Rotating Id
      69              :         ReturnErrorOnFailure(generateRotatingDeviceIdAsBinary(params, rotatingDeviceIdBuffer));
      70              :         // Adding the rotating device id to the TLV data
      71              :         ReturnErrorOnFailure(innerWriter.Put(ContextTag(kRotatingDeviceIdTag), rotatingDeviceIdBuffer));
      72              :     }
      73              : #endif
      74              : 
      75            1 :     ReturnErrorOnFailure(writer.CloseContainer(innerWriter));
      76              : 
      77            1 :     return writer.Finalize(&bufferHandle);
      78            1 : }
      79              : 
      80              : #if CHIP_ENABLE_ROTATING_DEVICE_ID
      81              : CHIP_ERROR AdditionalDataPayloadGenerator::generateRotatingDeviceIdAsBinary(AdditionalDataPayloadGeneratorParams & params,
      82              :                                                                             MutableByteSpan & rotatingDeviceIdBuffer)
      83              : {
      84              :     uint8_t hashOutputBuffer[kSHA256_Hash_Length];
      85              :     BufferWriter outputBufferWriter(rotatingDeviceIdBuffer);
      86              :     uint8_t lifetimeCounterBuffer[2];
      87              : 
      88              :     if (params.rotatingDeviceIdUniqueId.data() == nullptr)
      89              :     {
      90              :         return CHIP_ERROR_INVALID_ARGUMENT;
      91              :     }
      92              : 
      93              :     Put16(lifetimeCounterBuffer, params.rotatingDeviceIdLifetimeCounter);
      94              : 
      95              :     // Computing the Rotating Device Id
      96              :     // RDI = Lifetime_Counter + SuffixBytes(SHA256(Unique_Id + Lifetime_Counter), 16)
      97              : 
      98              :     Hash_SHA256_stream hash;
      99              :     MutableByteSpan hashOutputSpan(hashOutputBuffer);
     100              :     ReturnErrorOnFailure(hash.Begin());
     101              :     ReturnErrorOnFailure(hash.AddData(params.rotatingDeviceIdUniqueId));
     102              :     ReturnErrorOnFailure(hash.AddData(ByteSpan{ lifetimeCounterBuffer, sizeof(params.rotatingDeviceIdLifetimeCounter) }));
     103              :     ReturnErrorOnFailure(hash.Finish(hashOutputSpan));
     104              : 
     105              :     outputBufferWriter.Put16(params.rotatingDeviceIdLifetimeCounter);
     106              :     outputBufferWriter.Put(&hashOutputBuffer[kSHA256_Hash_Length - RotatingDeviceId::kHashSuffixLength],
     107              :                            RotatingDeviceId::kHashSuffixLength);
     108              :     VerifyOrReturnError(outputBufferWriter.Fit(), CHIP_ERROR_BUFFER_TOO_SMALL);
     109              :     rotatingDeviceIdBuffer.reduce_size(outputBufferWriter.Needed());
     110              :     return CHIP_NO_ERROR;
     111              : }
     112              : 
     113              : CHIP_ERROR AdditionalDataPayloadGenerator::generateRotatingDeviceIdAsHexString(AdditionalDataPayloadGeneratorParams & params,
     114              :                                                                                char * rotatingDeviceIdBuffer,
     115              :                                                                                size_t rotatingDeviceIdBufferSize,
     116              :                                                                                size_t & rotatingDeviceIdValueOutputSize)
     117              : {
     118              :     uint8_t rotatingDeviceIdInternalBuffer[RotatingDeviceId::kMaxLength];
     119              :     MutableByteSpan rotatingDeviceIdBufferTemp(rotatingDeviceIdInternalBuffer);
     120              :     ReturnErrorOnFailure(generateRotatingDeviceIdAsBinary(params, rotatingDeviceIdBufferTemp));
     121              : 
     122              :     VerifyOrReturnError(rotatingDeviceIdBufferSize >= RotatingDeviceId::kHexMaxLength, CHIP_ERROR_BUFFER_TOO_SMALL);
     123              :     ReturnErrorOnFailure(BytesToUppercaseHexString(rotatingDeviceIdBufferTemp.data(), rotatingDeviceIdBufferTemp.size(),
     124              :                                                    rotatingDeviceIdBuffer, rotatingDeviceIdBufferSize));
     125              :     rotatingDeviceIdValueOutputSize = rotatingDeviceIdBufferTemp.size() * 2;
     126              :     return CHIP_NO_ERROR;
     127              : }
     128              : #endif