I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <inttypes.h>
#include "I2PEndian.h"
#include <map>
#include <string>
#include "RouterContext.h"
#include "I2NPProtocol.h"
#include "Tunnel.h"
#include "TunnelPool.h"
#include "Timestamp.h"
#include "Destination.h"
#include "Garlic.h"
namespace i2p
{
namespace garlic
{
GarlicRoutingSession::GarlicRoutingSession (GarlicDestination * owner,
const i2p::data::RoutingDestination * destination, int numTags):
m_Owner (owner), m_Destination (destination), m_NumTags (numTags),
m_LeaseSetUpdated (numTags > 0)
{
// create new session tags and session key
m_Rnd.GenerateBlock (m_SessionKey, 32);
m_Encryption.SetKey (m_SessionKey);
}
GarlicRoutingSession::GarlicRoutingSession (const uint8_t * sessionKey, const SessionTag& sessionTag):
m_Owner (nullptr), m_Destination (nullptr), m_NumTags (1), m_LeaseSetUpdated (false)
{
memcpy (m_SessionKey, sessionKey, 32);
m_Encryption.SetKey (m_SessionKey);
m_SessionTags.push_back (sessionTag);
m_SessionTags.back ().creationTime = i2p::util::GetSecondsSinceEpoch ();
}
GarlicRoutingSession::~GarlicRoutingSession ()
{
for (auto it: m_UnconfirmedTagsMsgs)
delete it.second;
m_UnconfirmedTagsMsgs.clear ();
}
GarlicRoutingSession::UnconfirmedTags * GarlicRoutingSession::GenerateSessionTags ()
{
auto tags = new UnconfirmedTags (m_NumTags);
tags->tagsCreationTime = i2p::util::GetSecondsSinceEpoch ();
for (int i = 0; i < m_NumTags; i++)
{
m_Rnd.GenerateBlock (tags->sessionTags[i], 32);
tags->sessionTags[i].creationTime = tags->tagsCreationTime;
}
return tags;
}
void GarlicRoutingSession::TagsConfirmed (uint32_t msgID)
{
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
auto it = m_UnconfirmedTagsMsgs.find (msgID);
if (it != m_UnconfirmedTagsMsgs.end ())
{
UnconfirmedTags * tags = it->second;
if (ts < tags->tagsCreationTime + OUTGOING_TAGS_EXPIRATION_TIMEOUT)
{
for (int i = 0; i < tags->numTags; i++)
m_SessionTags.push_back (tags->sessionTags[i]);
}
m_UnconfirmedTagsMsgs.erase (it);
delete tags;
}
// delete expired unconfirmed tags
for (auto it = m_UnconfirmedTagsMsgs.begin (); it != m_UnconfirmedTagsMsgs.end ();)
{
if (ts >= it->second->tagsCreationTime + OUTGOING_TAGS_EXPIRATION_TIMEOUT)
{
delete it->second;
it = m_UnconfirmedTagsMsgs.erase (it);
}
else
it++;
}
}
I2NPMessage * GarlicRoutingSession::WrapSingleMessage (I2NPMessage * msg)
{
I2NPMessage * m = NewI2NPMessage ();
m->Align (12); // in order to get buf aligned to 16 (12 + 4)
size_t len = 0;
uint8_t * buf = m->GetPayload () + 4; // 4 bytes for length
// find non-expired tag
bool tagFound = false;
SessionTag tag;
if (m_NumTags > 0)
{
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
while (!m_SessionTags.empty ())
{
if (ts < m_SessionTags.front ().creationTime + OUTGOING_TAGS_EXPIRATION_TIMEOUT)
{
tag = m_SessionTags.front ();
m_SessionTags.pop_front (); // use same tag only once
tagFound = true;
break;
}
else
m_SessionTags.pop_front (); // remove expired tag
}
}
// create message
if (!tagFound) // new session
{
LogPrint ("No garlic tags available. Use ElGamal");
if (!m_Destination)
{
LogPrint ("Can't use ElGamal for unknown destination");
return nullptr;
}
// create ElGamal block
ElGamalBlock elGamal;
memcpy (elGamal.sessionKey, m_SessionKey, 32);
m_Rnd.GenerateBlock (elGamal.preIV, 32); // Pre-IV
uint8_t iv[32]; // IV is first 16 bytes
CryptoPP::SHA256().CalculateDigest(iv, elGamal.preIV, 32);
m_Destination->GetElGamalEncryption ()->Encrypt ((uint8_t *)&elGamal, sizeof(elGamal), buf, true);
m_Encryption.SetIV (iv);
buf += 514;
len += 514;
}
else // existing session
{
// session tag
memcpy (buf, tag, 32);
uint8_t iv[32]; // IV is first 16 bytes
CryptoPP::SHA256().CalculateDigest(iv, tag, 32);
m_Encryption.SetIV (iv);
buf += 32;
len += 32;
}
// AES block
len += CreateAESBlock (buf, msg);
*(uint32_t *)(m->GetPayload ()) = htobe32 (len);
m->len += len + 4;
FillI2NPMessageHeader (m, eI2NPGarlic);
if (msg)
DeleteI2NPMessage (msg);
return m;
}
size_t GarlicRoutingSession::CreateAESBlock (uint8_t * buf, const I2NPMessage * msg)
{
size_t blockSize = 0;
bool createNewTags = m_Owner && m_NumTags && ((int)m_SessionTags.size () <= m_NumTags/2);
UnconfirmedTags * newTags = createNewTags ? GenerateSessionTags () : nullptr;
*(uint16_t *)buf = newTags ? htobe16 (newTags->numTags) : 0; // tag count
blockSize += 2;
if (newTags) // session tags recreated
{
for (int i = 0; i < newTags->numTags; i++)
{
memcpy (buf + blockSize, newTags->sessionTags[i], 32); // tags
blockSize += 32;
}
}
uint32_t * payloadSize = (uint32_t *)(buf + blockSize);
blockSize += 4;
uint8_t * payloadHash = buf + blockSize;
blockSize += 32;
buf[blockSize] = 0; // flag
blockSize++;
size_t len = CreateGarlicPayload (buf + blockSize, msg, newTags);
*payloadSize = htobe32 (len);
CryptoPP::SHA256().CalculateDigest(payloadHash, buf + blockSize, len);
blockSize += len;
size_t rem = blockSize % 16;
if (rem)
blockSize += (16-rem); //padding
m_Encryption.Encrypt(buf, blockSize, buf);
return blockSize;
}
size_t GarlicRoutingSession::CreateGarlicPayload (uint8_t * payload, const I2NPMessage * msg, UnconfirmedTags * newTags)
{
uint64_t ts = i2p::util::GetMillisecondsSinceEpoch () + 5000; // 5 sec
uint32_t msgID = m_Rnd.GenerateWord32 ();
size_t size = 0;
uint8_t * numCloves = payload + size;
*numCloves = 0;
size++;
if (m_Owner)
{
if (newTags) // new session
{
// clove is DeliveryStatus
size += CreateDeliveryStatusClove (payload + size, msgID);
if (size > 0) // successive?
{
(*numCloves)++;
m_UnconfirmedTagsMsgs[msgID] = newTags;
m_Owner->DeliveryStatusSent (this, msgID);
}
else
LogPrint ("DeliveryStatus clove was not created");
}
if (m_LeaseSetUpdated)
{
m_LeaseSetUpdated = false;
// clove if our leaseSet must be attached
auto leaseSet = CreateDatabaseStoreMsg (m_Owner->GetLeaseSet ());
size += CreateGarlicClove (payload + size, leaseSet, false);
DeleteI2NPMessage (leaseSet);
(*numCloves)++;
}
}
if (msg) // clove message ifself if presented
{
size += CreateGarlicClove (payload + size, msg, m_Destination ? m_Destination->IsDestination () : false);
(*numCloves)++;
}
memset (payload + size, 0, 3); // certificate of message
size += 3;
*(uint32_t *)(payload + size) = htobe32 (msgID); // MessageID
size += 4;
*(uint64_t *)(payload + size) = htobe64 (ts); // Expiration of message
size += 8;
return size;
}
size_t GarlicRoutingSession::CreateGarlicClove (uint8_t * buf, const I2NPMessage * msg, bool isDestination)
{
uint64_t ts = i2p::util::GetMillisecondsSinceEpoch () + 5000; // 5 sec
size_t size = 0;
if (isDestination && m_Destination)
{
buf[size] = eGarlicDeliveryTypeDestination << 5;// delivery instructions flag destination
size++;
memcpy (buf + size, m_Destination->GetIdentHash (), 32);
size += 32;
}
else
{
buf[size] = 0;// delivery instructions flag local
size++;
}
memcpy (buf + size, msg->GetBuffer (), msg->GetLength ());
size += msg->GetLength ();
*(uint32_t *)(buf + size) = htobe32 (m_Rnd.GenerateWord32 ()); // CloveID
size += 4;
*(uint64_t *)(buf + size) = htobe64 (ts); // Expiration of clove
size += 8;
memset (buf + size, 0, 3); // certificate of clove
size += 3;
return size;
}
size_t GarlicRoutingSession::CreateDeliveryStatusClove (uint8_t * buf, uint32_t msgID)
{
size_t size = 0;
if (m_Owner)
{
auto leases = m_Owner->GetLeaseSet ()->GetNonExpiredLeases ();
if (!leases.empty ())
{
buf[size] = eGarlicDeliveryTypeTunnel << 5; // delivery instructions flag tunnel
size++;
uint32_t i = m_Rnd.GenerateWord32 (0, leases.size () - 1);
// hash and tunnelID sequence is reversed for Garlic
memcpy (buf + size, leases[i].tunnelGateway, 32); // To Hash
size += 32;
*(uint32_t *)(buf + size) = htobe32 (leases[i].tunnelID); // tunnelID
size += 4;
// create msg
I2NPMessage * msg = CreateDeliveryStatusMsg (msgID);
if (m_Owner)
{
//encrypt
uint8_t key[32], tag[32];
m_Rnd.GenerateBlock (key, 32); // random session key
m_Rnd.GenerateBlock (tag, 32); // random session tag
m_Owner->SubmitSessionKey (key, tag);
GarlicRoutingSession garlic (key, tag);
msg = garlic.WrapSingleMessage (msg);
}
memcpy (buf + size, msg->GetBuffer (), msg->GetLength ());
size += msg->GetLength ();
DeleteI2NPMessage (msg);
// fill clove
uint64_t ts = i2p::util::GetMillisecondsSinceEpoch () + 5000; // 5 sec
*(uint32_t *)(buf + size) = htobe32 (m_Rnd.GenerateWord32 ()); // CloveID
size += 4;
*(uint64_t *)(buf + size) = htobe64 (ts); // Expiration of clove
size += 8;
memset (buf + size, 0, 3); // certificate of clove
size += 3;
}
else
LogPrint ("All tunnels of local LeaseSet expired");
}
else
LogPrint ("Missing local LeaseSet");
return size;
}
GarlicDestination::~GarlicDestination ()
{
for (auto it: m_Sessions)
delete it.second;
m_Sessions.clear ();
}
void GarlicDestination::AddSessionKey (const uint8_t * key, const uint8_t * tag)
{
if (key)
{
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
auto decryption = std::make_shared<i2p::crypto::CBCDecryption>();
decryption->SetKey (key);
m_Tags[SessionTag(tag, ts)] = decryption;
}
}
bool GarlicDestination::SubmitSessionKey (const uint8_t * key, const uint8_t * tag)
{
AddSessionKey (key, tag);
return true;
}
void GarlicDestination::HandleGarlicMessage (I2NPMessage * msg)
{
uint8_t * buf = msg->GetPayload ();
uint32_t length = be32toh (*(uint32_t *)buf);
buf += 4; // length
auto it = m_Tags.find (SessionTag(buf));
if (it != m_Tags.end ())
{
// tag found. Use AES
uint8_t iv[32]; // IV is first 16 bytes
CryptoPP::SHA256().CalculateDigest(iv, buf, 32);
it->second->SetIV (iv);
it->second->Decrypt (buf + 32, length - 32, buf + 32);
HandleAESBlock (buf + 32, length - 32, it->second, msg->from);
m_Tags.erase (it); // tag might be used only once
}
else
{
// tag not found. Use ElGamal
ElGamalBlock elGamal;
if (i2p::crypto::ElGamalDecrypt (GetEncryptionPrivateKey (), buf, (uint8_t *)&elGamal, true))
{
auto decryption = std::make_shared<i2p::crypto::CBCDecryption>();
decryption->SetKey (elGamal.sessionKey);
uint8_t iv[32]; // IV is first 16 bytes
CryptoPP::SHA256().CalculateDigest(iv, elGamal.preIV, 32);
decryption->SetIV (iv);
decryption->Decrypt(buf + 514, length - 514, buf + 514);
HandleAESBlock (buf + 514, length - 514, decryption, msg->from);
}
else
LogPrint ("Failed to decrypt garlic");
}
DeleteI2NPMessage (msg);
// cleanup expired tags
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
if (ts > m_LastTagsCleanupTime + INCOMING_TAGS_EXPIRATION_TIMEOUT)
{
if (m_LastTagsCleanupTime)
{
int numExpiredTags = 0;
for (auto it = m_Tags.begin (); it != m_Tags.end ();)
{
if (ts > it->first.creationTime + INCOMING_TAGS_EXPIRATION_TIMEOUT)
{
numExpiredTags++;
it = m_Tags.erase (it);
}
else
it++;
}
LogPrint (numExpiredTags, " tags expired for ", GetIdentHash().ToBase64 ());
}
m_LastTagsCleanupTime = ts;
}
}
void GarlicDestination::HandleAESBlock (uint8_t * buf, size_t len, std::shared_ptr<i2p::crypto::CBCDecryption> decryption,
i2p::tunnel::InboundTunnel * from)
{
uint16_t tagCount = be16toh (*(uint16_t *)buf);
buf += 2; len -= 2;
if (tagCount > 0)
{
if (tagCount*32 > len)
{
LogPrint (eLogError, "Tag count ", tagCount, " exceeds length ", len);
return ;
}
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
for (int i = 0; i < tagCount; i++)
m_Tags[SessionTag(buf + i*32, ts)] = decryption;
}
buf += tagCount*32;
len -= tagCount*32;
uint32_t payloadSize = be32toh (*(uint32_t *)buf);
if (payloadSize > len)
{
LogPrint (eLogError, "Unexpected payload size ", payloadSize);
return;
}
buf += 4;
uint8_t * payloadHash = buf;
buf += 32;// payload hash.
if (*buf) // session key?
buf += 32; // new session key
buf++; // flag
// payload
uint8_t hash[32];
CryptoPP::SHA256().CalculateDigest(hash, buf, payloadSize);
if (memcmp (hash, payloadHash, 32)) // payload hash doesn't match
{
LogPrint ("Wrong payload hash");
return;
}
HandleGarlicPayload (buf, payloadSize, from);
}
void GarlicDestination::HandleGarlicPayload (uint8_t * buf, size_t len, i2p::tunnel::InboundTunnel * from)
{
int numCloves = buf[0];
LogPrint (numCloves," cloves");
buf++;
for (int i = 0; i < numCloves; i++)
{
// delivery instructions
uint8_t flag = buf[0];
buf++; // flag
if (flag & 0x80) // encrypted?
{
// TODO: implement
LogPrint ("Clove encrypted");
buf += 32;
}
GarlicDeliveryType deliveryType = (GarlicDeliveryType)((flag >> 5) & 0x03);
switch (deliveryType)
{
case eGarlicDeliveryTypeLocal:
LogPrint ("Garlic type local");
HandleI2NPMessage (buf, len, from);
break;
case eGarlicDeliveryTypeDestination:
LogPrint ("Garlic type destination");
buf += 32; // destination. check it later or for multiple destinations
HandleI2NPMessage (buf, len, from);
break;
case eGarlicDeliveryTypeTunnel:
{
LogPrint ("Garlic type tunnel");
// gwHash and gwTunnel sequence is reverted
uint8_t * gwHash = buf;
buf += 32;
uint32_t gwTunnel = be32toh (*(uint32_t *)buf);
buf += 4;
i2p::tunnel::OutboundTunnel * tunnel = nullptr;
if (from && from->GetTunnelPool ())
tunnel = from->GetTunnelPool ()->GetNextOutboundTunnel ();
if (tunnel) // we have send it through an outbound tunnel
{
I2NPMessage * msg = CreateI2NPMessage (buf, GetI2NPMessageLength (buf), from);
tunnel->SendTunnelDataMsg (gwHash, gwTunnel, msg);
}
else
LogPrint ("No outbound tunnels available for garlic clove");
break;
}
case eGarlicDeliveryTypeRouter:
LogPrint ("Garlic type router not supported");
buf += 32;
break;
default:
LogPrint ("Unknow garlic delivery type ", (int)deliveryType);
}
buf += GetI2NPMessageLength (buf); // I2NP
buf += 4; // CloveID
buf += 8; // Date
buf += 3; // Certificate
}
}
I2NPMessage * GarlicDestination::WrapMessage (const i2p::data::RoutingDestination& destination,
I2NPMessage * msg, bool attachLeaseSet)
{
if (attachLeaseSet) // we should maintain this session
{
auto session = GetRoutingSession (destination, 32); // 32 tags by default
return session->WrapSingleMessage (msg);
}
else // one time session
{
GarlicRoutingSession session (this, &destination, 0); // don't use tag if no LeaseSet
return session.WrapSingleMessage (msg);
}
}
GarlicRoutingSession * GarlicDestination::GetRoutingSession (
const i2p::data::RoutingDestination& destination, int numTags)
{
auto it = m_Sessions.find (destination.GetIdentHash ());
GarlicRoutingSession * session = nullptr;
if (it != m_Sessions.end ())
session = it->second;
if (!session)
{
session = new GarlicRoutingSession (this, &destination, numTags);
std::unique_lock<std::mutex> l(m_SessionsMutex);
m_Sessions[destination.GetIdentHash ()] = session;
}
return session;
}
void GarlicDestination::DeliveryStatusSent (GarlicRoutingSession * session, uint32_t msgID)
{
m_CreatedSessions[msgID] = session;
}
void GarlicDestination::HandleDeliveryStatusMessage (I2NPMessage * msg)
{
I2NPDeliveryStatusMsg * deliveryStatus = (I2NPDeliveryStatusMsg *)msg->GetPayload ();
uint32_t msgID = be32toh (deliveryStatus->msgID);
{
auto it = m_CreatedSessions.find (msgID);
if (it != m_CreatedSessions.end ())
{
it->second->TagsConfirmed (msgID);
m_CreatedSessions.erase (it);
LogPrint ("Garlic message ", msgID, " acknowledged");
}
}
DeleteI2NPMessage (msg);
}
void GarlicDestination::SetLeaseSetUpdated ()
{
std::unique_lock<std::mutex> l(m_SessionsMutex);
for (auto it: m_Sessions)
it.second->SetLeaseSetUpdated ();
}
void GarlicDestination::ProcessGarlicMessage (I2NPMessage * msg)
{
HandleGarlicMessage (msg);
}
void GarlicDestination::ProcessDeliveryStatusMessage (I2NPMessage * msg)
{
HandleDeliveryStatusMessage (msg);
}
}
}