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Auth: Port VMaNGOS implementation of TOTP for 1.12 #513

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Auth: Port VMaNGOS implementation of TOTP for 1.12 #513

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68b674e
Auth: only check token for post 1.12.3 clients
insunaa Jul 4, 2023
e8c2f75
Auth: Use PIN Field in 1.12.x for TOTP auth if applicable
insunaa Jul 4, 2023
218eb8a
Auth: Fix flag handling
insunaa Jul 4, 2023
1d970db
Auth: Actually fix flag handling
insunaa Jul 4, 2023
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111 changes: 106 additions & 5 deletions src/realmd/AuthSocket.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@
#include "AuthCodes.h"
#include "Auth/SRP6.h"
#include "Util/CommonDefines.h"
#include "Util/Util.h"

#include <openssl/md5.h>
#include <ctime>
Expand Down Expand Up @@ -473,13 +474,20 @@ bool AuthSocket::_HandleLogonChallenge()
if (!_token.empty() && _build >= 8606) // authenticator was added in 2.4.3
securityFlags = SECURITY_FLAG_AUTHENTICATOR;

if (!_token.empty() && _build <= 6141)
securityFlags = SECURITY_FLAG_PIN;

pkt << uint8(securityFlags); // security flags (0x0...0x04)

if (securityFlags & SECURITY_FLAG_PIN) // PIN input
{
pkt << uint32(0);
pkt << uint64(0);
pkt << uint64(0);
uint32 gridSeedPkt = m_gridSeed = static_cast<uint32>(0/*urand()*/);
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Leaving this as 0 instead of urand() (neither of which really need a static_cast, but the compiler will optimize that out anyway) means that the keypad on the client is not scrambled. Adding any other number (or urand()) here will scramble the keypad, making text entry more difficult for no real benefit. It's not a physical keypad where an attacker could look at your finger movements to determine the code you're entering, after all. If an attacker can see your screen, you have bigger problems.

Left it in in case someone sees the need to enable scrambling, tho.

EndianConvert(gridSeedPkt);
m_serverSecuritySalt.SetRand(16 * 8); // 16 bytes random
m_promptPin = true;

pkt << gridSeedPkt;
pkt.append(m_serverSecuritySalt.AsByteArray(16).data(), 16);
}

if (securityFlags & SECURITY_FLAG_UNK) // Matrix input
Expand Down Expand Up @@ -520,6 +528,14 @@ bool AuthSocket::_HandleLogonProof()
if (!Read((char*)&lp, sizeof(sAuthLogonProof_C)))
return false;


PINData pinData;

if (lp.securityFlags & SECURITY_FLAG_PIN)
{
if (!Read((char*)&pinData, sizeof(pinData)))
return false;
}
///- Session is closed unless overriden
_status = STATUS_CLOSED;

Expand Down Expand Up @@ -548,10 +564,23 @@ bool AuthSocket::_HandleLogonProof()
srp.HashSessionKey();
srp.CalculateProof(_login);

bool pinResult = true;

if (m_promptPin && (lp.securityFlags & SECURITY_FLAG_PIN))
pinResult = false;

if (m_promptPin && (lp.securityFlags & SECURITY_FLAG_PIN))
{
auto pin = generateToken(_token.c_str());

if (pin != uint32(-1))
pinResult = VerifyPinData(pin, pinData);
}

///- Check if SRP6 results match (password is correct), else send an error
if (!srp.Proof(lp.M1, 20))
if (!srp.Proof(lp.M1, 20) && pinResult)
{
if (lp.securityFlags & SECURITY_FLAG_AUTHENTICATOR || !_token.empty())
if (_build > 6141 && (lp.securityFlags & SECURITY_FLAG_AUTHENTICATOR || !_token.empty()))
{
uint8 pinCount;
if (!Read((char*)&pinCount, sizeof(uint8)))
Expand Down Expand Up @@ -1012,6 +1041,78 @@ bool AuthSocket::_HandleXferAccept()
return true;
}

// Verify PIN entry data
bool AuthSocket::VerifyPinData(uint32 pin, const PINData& clientData)
{
// remap the grid to match the client's layout
std::vector<uint8> grid { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
std::vector<uint8> remappedGrid(grid.size());

uint8* remappedIndex = remappedGrid.data();
uint32 seed = m_gridSeed;

for (size_t i = grid.size(); i > 0; --i)
{
auto remainder = seed % i;
seed /= i;
*remappedIndex = grid[remainder];

size_t copySize = i;
copySize -= remainder;
--copySize;

uint8* srcPtr = grid.data() + remainder + 1;
uint8* dstPtr = grid.data() + remainder;

std::copy(srcPtr, srcPtr + copySize, dstPtr);
++remappedIndex;
}

// convert the PIN to bytes (for ex. '1234' to {1, 2, 3, 4})
std::vector<uint8> pinBytes;

while (pin != 0)
{
pinBytes.push_back(pin % 10);
pin /= 10;
}

std::reverse(pinBytes.begin(), pinBytes.end());

// validate PIN length
if (pinBytes.size() < 4 || pinBytes.size() > 10)
return false; // PIN outside of expected range

// remap the PIN to calculate the expected client input sequence
for (size_t i = 0; i < pinBytes.size(); ++i)
{
auto index = std::find(remappedGrid.begin(), remappedGrid.end(), pinBytes[i]);
pinBytes[i] = std::distance(remappedGrid.begin(), index);
}

// convert PIN bytes to their ASCII values
for (size_t i = 0; i < pinBytes.size(); ++i)
pinBytes[i] += 0x30;

// validate the PIN, x = H(client_salt | H(server_salt | ascii(pin_bytes)))
Sha1Hash sha;
sha.UpdateData(m_serverSecuritySalt.AsByteArray());
sha.UpdateData(pinBytes.data(), pinBytes.size());
sha.Finalize();

BigNumber hash, clientHash;
hash.SetBinary(sha.GetDigest(), sha.GetLength());
clientHash.SetBinary(clientData.hash, 20);

sha.Initialize();
sha.UpdateData(clientData.salt, sizeof(clientData.salt));
sha.UpdateData(hash.AsByteArray());
sha.Finalize();
hash.SetBinary(sha.GetDigest(), sha.GetLength());

return !memcmp(hash.AsDecStr(), clientHash.AsDecStr(), 20);
}

int32 AuthSocket::generateToken(char const* b32key)
{
size_t keySize = strlen(b32key);
Expand Down
11 changes: 11 additions & 0 deletions src/realmd/AuthSocket.h
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,12 @@

#define HMAC_RES_SIZE 20

struct PINData
{
uint8 salt[16];
uint8 hash[20];
};

class AuthSocket : public MaNGOS::Socket
{
public:
Expand All @@ -48,6 +54,7 @@ class AuthSocket : public MaNGOS::Socket

void SendProof(Sha1Hash sha);
void LoadRealmlist(ByteBuffer& pkt, uint32 acctid, uint8 accountSecurityLevel = 0);
bool VerifyPinData(uint32 pin, const PINData& clientData);
int32 generateToken(char const* b32key);

uint8 getEligibleRealmCount(uint8 accountSecurityLevel);
Expand Down Expand Up @@ -90,6 +97,10 @@ class AuthSocket : public MaNGOS::Socket
uint16 _build;
AccountTypes _accountSecurityLevel;

BigNumber m_serverSecuritySalt;
uint32 m_gridSeed = 0;
bool m_promptPin = false;

boost::asio::deadline_timer m_timeoutTimer;

virtual bool ProcessIncomingData() override;
Expand Down