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Commit 357b2fbd authored by Henri Chataing's avatar Henri Chataing
Browse files

RootCanal/Gd: Fix RPA address check 

The check was implemented with the wrong byte order in mind.
This change fixes and documents the byte order, and corrects
the associated unit tests.

Test: atest --host bluetooth_test_gd_unit AddressWithTypeTest
Change-Id: I8dfca68756e5037b86fb6682b4bd869b0649ec8a
parent 8600bef8

system/gd/hci/address.h

+4 −0
Original line number Diff line number Diff line
@@ -38,6 +38,10 @@ class Address final : public packet::CustomFieldFixedSizeInterface<Address>, 
 public:

  static constexpr size_t kLength = 6;



  // Bluetooth MAC address bytes saved in little endian format.

  // The address MSB is address[5], the address LSB is address[0].

  // Note that the textual representation follows the big endian format,

  // ie. Address{0, 1, 2, 3, 4, 5} is represented as 05:04:03:02:01:00.

  std::array<uint8_t, kLength> address = {};



  Address() = default;

system/gd/hci/address_with_type.h

+7 −7
Original line number Diff line number Diff line
@@ -47,7 +47,7 @@ class AddressWithType final : public bluetooth::common::IRedactableLoggable { 


  /* Is this an Resolvable Private Address ? */

  inline bool IsRpa() const {

    return address_type_ == hci::AddressType::RANDOM_DEVICE_ADDRESS && ((address_.data())[0] & 0xc0) == 0x40;

    return address_type_ == hci::AddressType::RANDOM_DEVICE_ADDRESS && ((address_.data())[5] & 0xc0) == 0x40;

  }



  /* Is this an Resolvable Private Address, that was generated from given irk ? */
@@ -56,15 +56,15 @@ class AddressWithType final : public bluetooth::common::IRedactableLoggable { 


    /* use the 3 MSB of bd address as prand */

    uint8_t prand[3];

    prand[0] = address_.address[2];

    prand[1] = address_.address[1];

    prand[2] = address_.address[0];

    prand[0] = address_.address[3];

    prand[1] = address_.address[4];

    prand[2] = address_.address[5];

    /* generate X = E irk(R0, R1, R2) and R is random address 3 LSO */

    crypto_toolbox::Octet16 computed_hash = crypto_toolbox::aes_128(irk, &prand[0], 3);

    uint8_t hash[3];

    hash[0] = address_.address[5];

    hash[1] = address_.address[4];

    hash[2] = address_.address[3];

    hash[0] = address_.address[0];

    hash[1] = address_.address[1];

    hash[2] = address_.address[2];

    if (memcmp(computed_hash.data(), &hash[0], 3) == 0) {

      // match

      return true;

system/gd/hci/address_with_type_test.cc

+8 −9
Original line number Diff line number Diff line
@@ -73,25 +73,24 @@ TEST(AddressWithTypeTest, IsRpa) { 


  // Must have proper Most Significant Bit configuration

  EXPECT_FALSE(

      AddressWithType(Address{{0x30, 0x02, 0x03, 0x04, 0x05, 0x06}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

      AddressWithType(Address{{0x01, 0x02, 0x03, 0x04, 0x05, 0x06}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

  EXPECT_TRUE(

      AddressWithType(Address{{0x40, 0x02, 0x03, 0x04, 0x05, 0x03}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

      AddressWithType(Address{{0x01, 0x02, 0x03, 0x04, 0x05, 0x40}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

  EXPECT_TRUE(

      AddressWithType(Address{{0x50, 0x02, 0x03, 0x04, 0x05, 0x06}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

      AddressWithType(Address{{0x01, 0x02, 0x03, 0x04, 0x05, 0x50}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

  EXPECT_TRUE(

      AddressWithType(Address{{0x60, 0x02, 0x03, 0x04, 0x05, 0x06}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

      AddressWithType(Address{{0x01, 0x02, 0x03, 0x04, 0x05, 0x60}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

  EXPECT_TRUE(

      AddressWithType(Address{{0x70, 0x02, 0x03, 0x04, 0x05, 0x06}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

      AddressWithType(Address{{0x01, 0x02, 0x03, 0x04, 0x05, 0x70}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

  EXPECT_FALSE(

      AddressWithType(Address{{0x80, 0x02, 0x03, 0x04, 0x05, 0x06}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

      AddressWithType(Address{{0x01, 0x02, 0x03, 0x04, 0x05, 0x80}}, AddressType::RANDOM_DEVICE_ADDRESS).IsRpa());

}



TEST(AddressWithTypeTest, IsRpaThatMatchesIrk) {

  // Public address can't be RPA

  AddressWithType address_1 =

      AddressWithType(Address{{0x50, 0x02, 0x03, 0xC9, 0x12, 0xDE}}, AddressType::RANDOM_DEVICE_ADDRESS);

      AddressWithType(Address{{0xDE, 0x12, 0xC9, 0x03, 0x02, 0x50}}, AddressType::RANDOM_DEVICE_ADDRESS);

  AddressWithType address_2 =

      AddressWithType(Address{{0x50, 0x02, 0x03, 0xC9, 0x12, 0xDD}}, AddressType::RANDOM_DEVICE_ADDRESS);

      AddressWithType(Address{{0xDD, 0x12, 0xC9, 0x03, 0x02, 0x50}}, AddressType::RANDOM_DEVICE_ADDRESS);

  crypto_toolbox::Octet16 irk_1{0x90, 0x5e, 0x60, 0x59, 0xc9, 0x11, 0x43, 0x7b,

                                0x04, 0x09, 0x6a, 0x53, 0x28, 0xe6, 0x59, 0x6d};

tools/rootcanal/include/hci/address.h

+5 −1
Original line number Diff line number Diff line 
/******************************************************************************

 *

 *  Copyright 2019 The Android Open Source Project

 *  Copyright 2022 The Android Open Source Project

 *

 *  Licensed under the Apache License, Version 2.0 (the "License");

 *  you may not use this file except in compliance with the License.
@@ -34,6 +34,10 @@ class Address final : public packet::CustomFieldFixedSizeInterface<Address> { 
 public:

  static constexpr size_t kLength = 6;



  // Bluetooth MAC address bytes saved in little endian format.

  // The address MSB is address[5], the address LSB is address[0].

  // Note that the textual representation follows the big endian format,

  // ie. Address{0, 1, 2, 3, 4, 5} is represented as 05:04:03:02:01:00.

  std::array<uint8_t, kLength> address = {};



  constexpr Address() = default;

tools/rootcanal/include/hci/address_with_type.h

+9 −14
Original line number Diff line number Diff line 
/******************************************************************************

 *

 *  Copyright 2019 The Android Open Source Project

 *  Copyright 2022 The Android Open Source Project

 *

 *  Licensed under the Apache License, Version 2.0 (the "License");

 *  you may not use this file except in compliance with the License.
@@ -45,7 +45,7 @@ class AddressWithType final { 
  /* Is this an Resolvable Private Address ? */

  inline bool IsRpa() const {

    return address_type_ == hci::AddressType::RANDOM_DEVICE_ADDRESS &&

           ((address_.data())[0] & 0xc0) == 0x40;

           ((address_.data())[5] & 0xc0) == 0x40;

  }



  /* Is this an Resolvable Private Address, that was generated from given irk ?
@@ -55,22 +55,17 @@ class AddressWithType final { 


    /* use the 3 MSB of bd address as prand */

    uint8_t prand[3];

    prand[0] = address_.address[2];

    prand[1] = address_.address[1];

    prand[2] = address_.address[0];

    prand[0] = address_.address[3];

    prand[1] = address_.address[4];

    prand[2] = address_.address[5];

    /* generate X = E irk(R0, R1, R2) and R is random address 3 LSO */

    rootcanal::crypto::Octet16 computed_hash =

        rootcanal::crypto::aes_128(irk, &prand[0], 3);

    uint8_t hash[3];

    hash[0] = address_.address[5];

    hash[1] = address_.address[4];

    hash[2] = address_.address[3];

    if (memcmp(computed_hash.data(), &hash[0], 3) == 0) {

      // match

      return true;

    }

    // not a match

    return false;

    hash[0] = address_.address[0];

    hash[1] = address_.address[1];

    hash[2] = address_.address[2];

    return memcmp(computed_hash.data(), &hash[0], 3) == 0;

  }



  bool operator<(const AddressWithType& rhs) const {