NetworkPkg/UefiPxeBcDxe/GoogleTest/PxeBcDhcp6GoogleTest.cpp

/** @file
  Host based unit test for PxeBcDhcp6.c.

  Copyright (c) Microsoft Corporation
  SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/GoogleTestLib.h>
#include <GoogleTest/Library/MockUefiLib.h>
#include <GoogleTest/Library/MockUefiRuntimeServicesTableLib.h>
#include <GoogleTest/Library/MockUefiBootServicesTableLib.h>
#include <GoogleTest/Protocol/MockRng.h>

extern "C" {
  #include <Uefi.h>
  #include <Library/BaseLib.h>
  #include <Library/DebugLib.h>
  #include "../PxeBcImpl.h"
  #include "../PxeBcDhcp6.h"
  #include "PxeBcDhcp6GoogleTest.h"
}

///////////////////////////////////////////////////////////////////////////////
// Definitions
///////////////////////////////////////////////////////////////////////////////

#define PACKET_SIZE            (1500)
#define REQUEST_OPTION_LENGTH  (120)

typedef struct {
  UINT16    OptionCode;   // The option code for DHCP6_OPT_SERVER_ID (e.g., 0x03)
  UINT16    OptionLen;    // The length of the option (e.g., 16 bytes)
  UINT8     ServerId[16]; // The 16-byte DHCPv6 Server Identifier
} DHCP6_OPTION_SERVER_ID;

///////////////////////////////////////////////////////////////////////////////
/// Symbol Definitions
///////////////////////////////////////////////////////////////////////////////

EFI_STATUS
EFIAPI
MockUdpWrite (
  IN EFI_PXE_BASE_CODE_PROTOCOL      *This,
  IN UINT16                          OpFlags,
  IN EFI_IP_ADDRESS                  *DestIp,
  IN EFI_PXE_BASE_CODE_UDP_PORT      *DestPort,
  IN EFI_IP_ADDRESS                  *GatewayIp   OPTIONAL,
  IN EFI_IP_ADDRESS                  *SrcIp       OPTIONAL,
  IN OUT EFI_PXE_BASE_CODE_UDP_PORT  *SrcPort     OPTIONAL,
  IN UINTN                           *HeaderSize  OPTIONAL,
  IN VOID                            *HeaderPtr   OPTIONAL,
  IN UINTN                           *BufferSize,
  IN VOID                            *BufferPtr
  )
{
  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
MockUdpRead (
  IN EFI_PXE_BASE_CODE_PROTOCOL      *This,
  IN UINT16                          OpFlags,
  IN OUT EFI_IP_ADDRESS              *DestIp      OPTIONAL,
  IN OUT EFI_PXE_BASE_CODE_UDP_PORT  *DestPort    OPTIONAL,
  IN OUT EFI_IP_ADDRESS              *SrcIp       OPTIONAL,
  IN OUT EFI_PXE_BASE_CODE_UDP_PORT  *SrcPort     OPTIONAL,
  IN UINTN                           *HeaderSize  OPTIONAL,
  IN VOID                            *HeaderPtr   OPTIONAL,
  IN OUT UINTN                       *BufferSize,
  IN VOID                            *BufferPtr
  )
{
  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
MockConfigure (
  IN EFI_UDP6_PROTOCOL     *This,
  IN EFI_UDP6_CONFIG_DATA  *UdpConfigData OPTIONAL
  )
{
  return EFI_SUCCESS;
}

// Needed by PxeBcSupport
EFI_STATUS
PxeBcDns6 (
  IN PXEBC_PRIVATE_DATA  *Private,
  IN     CHAR16          *HostName,
  OUT EFI_IPv6_ADDRESS   *IpAddress
  )
{
  return EFI_SUCCESS;
}

UINT32
PxeBcBuildDhcp6Options (
  IN  PXEBC_PRIVATE_DATA       *Private,
  OUT EFI_DHCP6_PACKET_OPTION  **OptList,
  IN  UINT8                    *Buffer
  )
{
  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
QueueDpc (
  IN EFI_TPL            DpcTpl,
  IN EFI_DPC_PROCEDURE  DpcProcedure,
  IN VOID               *DpcContext    OPTIONAL
  )
{
  return EFI_SUCCESS;
}

///////////////////////////////////////////////////////////////////////////////
// PxeBcHandleDhcp6OfferTest Tests
///////////////////////////////////////////////////////////////////////////////

class PxeBcHandleDhcp6OfferTest : public ::testing::Test {
public:
  PXEBC_PRIVATE_DATA Private = { 0 };
  EFI_UDP6_PROTOCOL Udp6Read;
  EFI_PXE_BASE_CODE_MODE Mode = { 0 };

protected:
  // Add any setup code if needed
  virtual void
  SetUp (
    )
  {
    Private.Dhcp6Request = (EFI_DHCP6_PACKET *)AllocateZeroPool (PACKET_SIZE);

    // Need to setup the EFI_PXE_BASE_CODE_PROTOCOL
    // The function under test really only needs the following:
    //  UdpWrite
    //  UdpRead

    Private.PxeBc.UdpWrite = (EFI_PXE_BASE_CODE_UDP_WRITE)MockUdpWrite;
    Private.PxeBc.UdpRead  = (EFI_PXE_BASE_CODE_UDP_READ)MockUdpRead;

    // Need to setup EFI_UDP6_PROTOCOL
    // The function under test really only needs the following:
    //  Configure

    Udp6Read.Configure = (EFI_UDP6_CONFIGURE)MockConfigure;
    Private.Udp6Read   = &Udp6Read;

    // Need to setup the EFI_PXE_BASE_CODE_MODE
    Private.PxeBc.Mode = &Mode;

    // for this test it doesn't really matter what the Dhcpv6 ack is set to
  }

  // Add any cleanup code if needed
  virtual void
  TearDown (
    )
  {
    if (Private.Dhcp6Request != NULL) {
      FreePool (Private.Dhcp6Request);
    }

    // Clean up any resources or variables
  }
};

// Note:
// Testing PxeBcHandleDhcp6Offer() is difficult because it depends on a
// properly setup Private structure. Attempting to properly test this function
// without a significant refactor is a fools errand. Instead, we will test
// that we can prevent an overflow in the function.
TEST_F (PxeBcHandleDhcp6OfferTest, BasicUsageTest) {
  PXEBC_DHCP6_PACKET_CACHE  *Cache6 = NULL;
  EFI_DHCP6_PACKET_OPTION   Option  = { 0 };

  Private.SelectIndex = 1; // SelectIndex is 1-based
  Cache6              = &Private.OfferBuffer[Private.SelectIndex - 1].Dhcp6;

  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER] = &Option;
  // Setup the DHCPv6 offer packet
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpCode = DHCP6_OPT_SERVER_ID;
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpLen  = NTOHS (1337);

  ASSERT_EQ (PxeBcHandleDhcp6Offer (&(PxeBcHandleDhcp6OfferTest::Private)), EFI_DEVICE_ERROR);
}

///////////////////////////////////////////////////////////////////////////////
// PxeBcCacheDnsServerAddresses Tests
///////////////////////////////////////////////////////////////////////////////

class PxeBcCacheDnsServerAddressesTest : public ::testing::Test {
public:
  PXEBC_PRIVATE_DATA Private = { 0 };

protected:
  // Add any setup code if needed
  virtual void
  SetUp (
    )
  {
  }

  // Add any cleanup code if needed
  virtual void
  TearDown (
    )
  {
  }
};

// Test Description
// Test that we cache the DNS server address from the DHCPv6 offer packet
TEST_F (PxeBcCacheDnsServerAddressesTest, BasicUsageTest) {
  UINT8                     SearchPattern[16] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF };
  EFI_DHCP6_PACKET_OPTION   *Option;
  PXEBC_DHCP6_PACKET_CACHE  *Cache6 = NULL;

  Option = (EFI_DHCP6_PACKET_OPTION *)AllocateZeroPool (sizeof (EFI_DHCP6_PACKET_OPTION) + sizeof (SearchPattern));
  ASSERT_NE (Option, nullptr);

  Option->OpCode = DHCP6_OPT_SERVER_ID;
  Option->OpLen  = NTOHS (sizeof (SearchPattern));
  CopyMem (Option->Data, SearchPattern, sizeof (SearchPattern));

  Private.SelectIndex                         = 1; // SelectIndex is 1-based
  Cache6                                      = &Private.OfferBuffer[Private.SelectIndex - 1].Dhcp6;
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER] = Option;

  Private.DnsServer = nullptr;

  ASSERT_EQ (PxeBcCacheDnsServerAddresses (&(PxeBcCacheDnsServerAddressesTest::Private), Cache6), EFI_SUCCESS);
  ASSERT_NE (Private.DnsServer, nullptr);
  ASSERT_EQ (CompareMem (Private.DnsServer, SearchPattern, sizeof (SearchPattern)), 0);

  if (Private.DnsServer) {
    FreePool (Private.DnsServer);
  }

  if (Option) {
    FreePool (Option);
  }
}

// Test Description
// Test that we can prevent an overflow in the function
TEST_F (PxeBcCacheDnsServerAddressesTest, AttemptOverflowTest) {
  EFI_DHCP6_PACKET_OPTION   Option  = { 0 };
  PXEBC_DHCP6_PACKET_CACHE  *Cache6 = NULL;

  Private.SelectIndex                         = 1; // SelectIndex is 1-based
  Cache6                                      = &Private.OfferBuffer[Private.SelectIndex - 1].Dhcp6;
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER] = &Option;
  // Setup the DHCPv6 offer packet
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpCode = DHCP6_OPT_SERVER_ID;
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpLen  = NTOHS (1337);

  Private.DnsServer = NULL;

  ASSERT_EQ (PxeBcCacheDnsServerAddresses (&(PxeBcCacheDnsServerAddressesTest::Private), Cache6), EFI_DEVICE_ERROR);
  ASSERT_EQ (Private.DnsServer, nullptr);

  if (Private.DnsServer) {
    FreePool (Private.DnsServer);
  }
}

// Test Description
// Test that we can prevent an underflow in the function
TEST_F (PxeBcCacheDnsServerAddressesTest, AttemptUnderflowTest) {
  EFI_DHCP6_PACKET_OPTION   Option  = { 0 };
  PXEBC_DHCP6_PACKET_CACHE  *Cache6 = NULL;

  Private.SelectIndex                         = 1; // SelectIndex is 1-based
  Cache6                                      = &Private.OfferBuffer[Private.SelectIndex - 1].Dhcp6;
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER] = &Option;
  // Setup the DHCPv6 offer packet
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpCode = DHCP6_OPT_SERVER_ID;
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpLen  = NTOHS (2);

  Private.DnsServer = NULL;

  ASSERT_EQ (PxeBcCacheDnsServerAddresses (&(PxeBcCacheDnsServerAddressesTest::Private), Cache6), EFI_DEVICE_ERROR);
  ASSERT_EQ (Private.DnsServer, nullptr);

  if (Private.DnsServer) {
    FreePool (Private.DnsServer);
  }
}

// Test Description
// Test that we can handle recursive dns (multiple dns entries)
TEST_F (PxeBcCacheDnsServerAddressesTest, MultipleDnsEntries) {
  EFI_DHCP6_PACKET_OPTION   *Option = NULL;
  PXEBC_DHCP6_PACKET_CACHE  *Cache6 = NULL;

  EFI_IPv6_ADDRESS  addresses[2] = {
    // 2001:db8:85a3::8a2e:370:7334
    { 0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x00, 0x00, 0x00, 0x00, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x34 },
    // fe80::d478:91c3:ecd7:4ff9
    { 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xd4, 0x78, 0x91, 0xc3, 0xec, 0xd7, 0x4f, 0xf9 }
  };

  Option = (EFI_DHCP6_PACKET_OPTION *)AllocatePool (sizeof (*Option) + sizeof (addresses));
  if (Option == NULL) {
    ASSERT_NE (Option, nullptr);
  }

  Private.SelectIndex                         = 1; // SelectIndex is 1-based
  Cache6                                      = &Private.OfferBuffer[Private.SelectIndex - 1].Dhcp6;
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER] = Option;
  // Setup the DHCPv6 offer packet
  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpCode = DHCP6_OPT_SERVER_ID;

  CopyMem (Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->Data, addresses, sizeof (addresses));

  Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpLen = NTOHS (sizeof (addresses));

  Private.DnsServer = NULL;

  ASSERT_EQ (PxeBcCacheDnsServerAddresses (&(PxeBcCacheDnsServerAddressesTest::Private), Cache6), EFI_SUCCESS);

  ASSERT_NE (Private.DnsServer, nullptr);

  //
  // This is expected to fail until DnsServer supports multiple DNS servers
  //
  // This is tracked in https://bugzilla.tianocore.org/show_bug.cgi?id=1886
  //
  // Disabling:
  // ASSERT_EQ (CompareMem(Private.DnsServer, &addresses, sizeof(addresses)), 0);

  if (Private.DnsServer) {
    FreePool (Private.DnsServer);
  }

  if (Option) {
    FreePool (Option);
  }
}

///////////////////////////////////////////////////////////////////////////////
// PxeBcRequestBootServiceTest Test Cases
///////////////////////////////////////////////////////////////////////////////

class PxeBcRequestBootServiceTest : public ::testing::Test {
public:
  PXEBC_PRIVATE_DATA Private = { 0 };
  EFI_UDP6_PROTOCOL Udp6Read;

protected:
  // Add any setup code if needed
  virtual void
  SetUp (
    )
  {
    Private.Dhcp6Request = (EFI_DHCP6_PACKET *)AllocateZeroPool (PACKET_SIZE);

    // Need to setup the EFI_PXE_BASE_CODE_PROTOCOL
    // The function under test really only needs the following:
    //  UdpWrite
    //  UdpRead

    Private.PxeBc.UdpWrite = (EFI_PXE_BASE_CODE_UDP_WRITE)MockUdpWrite;
    Private.PxeBc.UdpRead  = (EFI_PXE_BASE_CODE_UDP_READ)MockUdpRead;

    // Need to setup EFI_UDP6_PROTOCOL
    // The function under test really only needs the following:
    //  Configure

    Udp6Read.Configure = (EFI_UDP6_CONFIGURE)MockConfigure;
    Private.Udp6Read   = &Udp6Read;
  }

  // Add any cleanup code if needed
  virtual void
  TearDown (
    )
  {
    if (Private.Dhcp6Request != NULL) {
      FreePool (Private.Dhcp6Request);
    }

    // Clean up any resources or variables
  }
};

TEST_F (PxeBcRequestBootServiceTest, ServerDiscoverBasicUsageTest) {
  PxeBcRequestBootServiceTest::Private.OfferBuffer[0].Dhcp6.OfferType = PxeOfferTypeProxyBinl;

  DHCP6_OPTION_SERVER_ID  Server = { 0 };

  Server.OptionCode =  HTONS (DHCP6_OPT_SERVER_ID);
  Server.OptionLen  = HTONS (16); // valid length
  UINT8  Index = 0;

  EFI_DHCP6_PACKET  *Packet = (EFI_DHCP6_PACKET *)&Private.OfferBuffer[Index].Dhcp6.Packet.Offer;

  UINT8  *Cursor = (UINT8 *)(Packet->Dhcp6.Option);

  CopyMem (Cursor, &Server, sizeof (Server));
  Cursor += sizeof (Server);

  // Update the packet length
  Packet->Length = (UINT16)(Cursor - (UINT8 *)Packet);
  Packet->Size   = PACKET_SIZE;

  ASSERT_EQ (PxeBcRequestBootService (&(PxeBcRequestBootServiceTest::Private), Index), EFI_SUCCESS);
}

TEST_F (PxeBcRequestBootServiceTest, AttemptDiscoverOverFlowExpectFailure) {
  PxeBcRequestBootServiceTest::Private.OfferBuffer[0].Dhcp6.OfferType = PxeOfferTypeProxyBinl;

  DHCP6_OPTION_SERVER_ID  Server = { 0 };

  Server.OptionCode =  HTONS (DHCP6_OPT_SERVER_ID);
  Server.OptionLen  = HTONS (1500); // This length would overflow without a check
  UINT8  Index = 0;

  EFI_DHCP6_PACKET  *Packet = (EFI_DHCP6_PACKET *)&Private.OfferBuffer[Index].Dhcp6.Packet.Offer;

  UINT8  *Cursor = (UINT8 *)(Packet->Dhcp6.Option);

  CopyMem (Cursor, &Server, sizeof (Server));
  Cursor += sizeof (Server);

  // Update the packet length
  Packet->Length = (UINT16)(Cursor - (UINT8 *)Packet);
  Packet->Size   = PACKET_SIZE;

  // This is going to be stopped by the duid overflow check
  ASSERT_EQ (PxeBcRequestBootService (&(PxeBcRequestBootServiceTest::Private), Index), EFI_INVALID_PARAMETER);
}

TEST_F (PxeBcRequestBootServiceTest, RequestBasicUsageTest) {
  EFI_DHCP6_PACKET_OPTION  RequestOpt = { 0 }; // the data section doesn't really matter

  RequestOpt.OpCode = HTONS (0x1337);
  RequestOpt.OpLen  = 0; // valid length

  UINT8  Index = 0;

  EFI_DHCP6_PACKET  *Packet = (EFI_DHCP6_PACKET *)&Private.Dhcp6Request[Index];

  UINT8  *Cursor = (UINT8 *)(Packet->Dhcp6.Option);

  CopyMem (Cursor, &RequestOpt, sizeof (RequestOpt));
  Cursor += sizeof (RequestOpt);

  // Update the packet length
  Packet->Length = (UINT16)(Cursor - (UINT8 *)Packet);
  Packet->Size   = PACKET_SIZE;

  ASSERT_EQ (PxeBcRequestBootService (&(PxeBcRequestBootServiceTest::Private), Index), EFI_SUCCESS);
}

TEST_F (PxeBcRequestBootServiceTest, AttemptRequestOverFlowExpectFailure) {
  EFI_DHCP6_PACKET_OPTION  RequestOpt = { 0 }; // the data section doesn't really matter

  RequestOpt.OpCode = HTONS (0x1337);
  RequestOpt.OpLen  = 1500; // this length would overflow without a check

  UINT8  Index = 0;

  EFI_DHCP6_PACKET  *Packet = (EFI_DHCP6_PACKET *)&Private.Dhcp6Request[Index];

  UINT8  *Cursor = (UINT8 *)(Packet->Dhcp6.Option);

  CopyMem (Cursor, &RequestOpt, sizeof (RequestOpt));
  Cursor += sizeof (RequestOpt);

  // Update the packet length
  Packet->Length = (UINT16)(Cursor - (UINT8 *)Packet);
  Packet->Size   = PACKET_SIZE;

  ASSERT_EQ (PxeBcRequestBootService (&(PxeBcRequestBootServiceTest::Private), Index), EFI_OUT_OF_RESOURCES);
}

///////////////////////////////////////////////////////////////////////////////
// PxeBcDhcp6Discover Test
///////////////////////////////////////////////////////////////////////////////

class PxeBcDhcp6DiscoverTest : public ::testing::Test {
public:
  PXEBC_PRIVATE_DATA Private = { 0 };
  // create a mock md5 hash
  UINT8 Md5Hash[16] = { 0 };

  EFI_UDP6_PROTOCOL Udp6Read;

protected:
  MockUefiRuntimeServicesTableLib RtServicesMock;
  MockUefiBootServicesTableLib BsMock;
  MockRng RngMock;

  // Add any setup code if needed
  virtual void
  SetUp (
    )
  {
    Private.Dhcp6Request = (EFI_DHCP6_PACKET *)AllocateZeroPool (PACKET_SIZE);

    // Need to setup the EFI_PXE_BASE_CODE_PROTOCOL
    // The function under test really only needs the following:
    //  UdpWrite
    //  UdpRead

    Private.PxeBc.UdpWrite = (EFI_PXE_BASE_CODE_UDP_WRITE)MockUdpWrite;
    Private.PxeBc.UdpRead  = (EFI_PXE_BASE_CODE_UDP_READ)MockUdpRead;

    // Need to setup EFI_UDP6_PROTOCOL
    // The function under test really only needs the following:
    //  Configure

    Udp6Read.Configure = (EFI_UDP6_CONFIGURE)MockConfigure;
    Private.Udp6Read   = &Udp6Read;
  }

  // Add any cleanup code if needed
  virtual void
  TearDown (
    )
  {
    if (Private.Dhcp6Request != NULL) {
      FreePool (Private.Dhcp6Request);
    }

    // Clean up any resources or variables
  }
};

// Test Description
// This will cause an overflow by an untrusted packet during the option parsing
TEST_F (PxeBcDhcp6DiscoverTest, BasicOverflowTest) {
  EFI_IPv6_ADDRESS         DestIp     = { 0 };
  EFI_DHCP6_PACKET_OPTION  RequestOpt = { 0 }; // the data section doesn't really matter

  RequestOpt.OpCode = HTONS (0x1337);
  RequestOpt.OpLen  = HTONS (0xFFFF); // overflow

  UINT8  *Cursor = (UINT8 *)(Private.Dhcp6Request->Dhcp6.Option);

  CopyMem (Cursor, &RequestOpt, sizeof (RequestOpt));
  Cursor += sizeof (RequestOpt);

  Private.Dhcp6Request->Length = (UINT16)(Cursor - (UINT8 *)Private.Dhcp6Request);

  EXPECT_CALL (BsMock, gBS_LocateProtocol)
    .WillOnce (
       ::testing::DoAll (
                    ::testing::SetArgPointee<2> (::testing::ByRef (gRngProtocol)),
                    ::testing::Return (EFI_SUCCESS)
                    )
       );

  EXPECT_CALL (RngMock, GetRng)
    .WillOnce (
       ::testing::DoAll (
                    ::testing::SetArgPointee<3> (::testing::ByRef (Md5Hash[0])),
                    ::testing::Return (EFI_SUCCESS)
                    )
       );

  ASSERT_EQ (
    PxeBcDhcp6Discover (
      &(PxeBcDhcp6DiscoverTest::Private),
      0,
      NULL,
      FALSE,
      (EFI_IP_ADDRESS *)&DestIp
      ),
    EFI_OUT_OF_RESOURCES
    );
}

// Test Description
// This will test that we can handle a packet with a valid option length
TEST_F (PxeBcDhcp6DiscoverTest, BasicUsageTest) {
  EFI_IPv6_ADDRESS         DestIp     = { 0 };
  EFI_DHCP6_PACKET_OPTION  RequestOpt = { 0 }; // the data section doesn't really matter

  RequestOpt.OpCode = HTONS (0x1337);
  RequestOpt.OpLen  = HTONS (0x30);

  UINT8  *Cursor = (UINT8 *)(Private.Dhcp6Request->Dhcp6.Option);

  CopyMem (Cursor, &RequestOpt, sizeof (RequestOpt));
  Cursor += sizeof (RequestOpt);

  Private.Dhcp6Request->Length = (UINT16)(Cursor - (UINT8 *)Private.Dhcp6Request);

  EXPECT_CALL (BsMock, gBS_LocateProtocol)
    .WillOnce (
       ::testing::DoAll (
                    ::testing::SetArgPointee<2> (::testing::ByRef (gRngProtocol)),
                    ::testing::Return (EFI_SUCCESS)
                    )
       );

  EXPECT_CALL (RngMock, GetRng)
    .WillOnce (
       ::testing::DoAll (
                    ::testing::SetArgPointee<3> (::testing::ByRef (Md5Hash[0])),
                    ::testing::Return (EFI_SUCCESS)
                    )
       );

  ASSERT_EQ (
    PxeBcDhcp6Discover (
      &(PxeBcDhcp6DiscoverTest::Private),
      0,
      NULL,
      FALSE,
      (EFI_IP_ADDRESS *)&DestIp
      ),
    EFI_SUCCESS
    );
}

TEST_F (PxeBcDhcp6DiscoverTest, MultipleRequestsAttemptOverflow) {
  EFI_IPv6_ADDRESS         DestIp     = { 0 };
  EFI_DHCP6_PACKET_OPTION  RequestOpt = { 0 }; // the data section doesn't really matter

  RequestOpt.OpCode = HTONS (0x1337);
  RequestOpt.OpLen  = HTONS (REQUEST_OPTION_LENGTH); // this length would overflow without a check
  UINT8  RequestOptBuffer[REQUEST_OPTION_LENGTH] = { 0 };

  // make sure we have enough space for 10 of these options
  ASSERT_TRUE (REQUEST_OPTION_LENGTH * 10 <= PACKET_SIZE);

  UINT8             Index   = 0;
  EFI_DHCP6_PACKET  *Packet = (EFI_DHCP6_PACKET *)&Private.Dhcp6Request[Index];
  UINT8             *Cursor = (UINT8 *)(Packet->Dhcp6.Option);

  // let's add 10 of these options - this should overflow
  for (UINT8 i = 0; i < 10; i++) {
    CopyMem (Cursor, &RequestOpt, sizeof (RequestOpt));
    Cursor += sizeof (RequestOpt) - 1;
    CopyMem (Cursor, RequestOptBuffer, REQUEST_OPTION_LENGTH);
    Cursor += REQUEST_OPTION_LENGTH;
  }

  // Update the packet length
  Packet->Length = (UINT16)(Cursor - (UINT8 *)Packet);
  Packet->Size   = PACKET_SIZE;

  // Make sure we're larger than the buffer we're trying to write into
  ASSERT_TRUE (Packet->Length > sizeof (EFI_PXE_BASE_CODE_DHCPV6_PACKET));

  EXPECT_CALL (BsMock, gBS_LocateProtocol)
    .WillOnce (
       ::testing::DoAll (
                    ::testing::SetArgPointee<2> (::testing::ByRef (gRngProtocol)),
                    ::testing::Return (EFI_SUCCESS)
                    )
       );

  EXPECT_CALL (RngMock, GetRng)
    .WillOnce (
       ::testing::DoAll (
                    ::testing::SetArgPointee<3> (::testing::ByRef (Md5Hash[0])),
                    ::testing::Return (EFI_SUCCESS)
                    )
       );

  ASSERT_EQ (
    PxeBcDhcp6Discover (
      &(PxeBcDhcp6DiscoverTest::Private),
      0,
      NULL,
      FALSE,
      (EFI_IP_ADDRESS *)&DestIp
      ),
    EFI_OUT_OF_RESOURCES
    );
}