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i2pd/Garlic.cpp

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#include <inttypes.h>
#include "I2PEndian.h"
#include <map>
#include <string>
#include <openssl/rand.h>
#include <openssl/sha.h>
#include "RouterContext.h"
#include "I2NPProtocol.h"
#include "Tunnel.h"
#include "TunnelPool.h"
#include "Timestamp.h"
#include "Log.h"
#include "Garlic.h"
namespace i2p
{
namespace garlic
{
GarlicRoutingSession::GarlicRoutingSession (GarlicDestination * owner,
std::shared_ptr<const i2p::data::RoutingDestination> destination, int numTags, bool attachLeaseSet):
m_Owner (owner), m_Destination (destination), m_NumTags (numTags),
m_LeaseSetUpdateStatus (attachLeaseSet ? eLeaseSetUpdated : eLeaseSetDoNotSend),
m_ElGamalEncryption (new i2p::crypto::ElGamalEncryption (destination->GetEncryptionPublicKey ()))
{
// create new session tags and session key
RAND_bytes (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_LeaseSetUpdateStatus (eLeaseSetDoNotSend)
{
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++)
{
RAND_bytes (tags->sessionTags[i], 32);
tags->sessionTags[i].creationTime = tags->tagsCreationTime;
}
return tags;
}
void GarlicRoutingSession::MessageConfirmed (uint32_t msgID)
{
TagsConfirmed (msgID);
if (msgID == m_LeaseSetUpdateMsgID)
{
m_LeaseSetUpdateStatus = eLeaseSetUpToDate;
LogPrint (eLogInfo, "Garlic: LeaseSet update confirmed");
}
else
CleanupExpiredTags ();
}
void GarlicRoutingSession::TagsConfirmed (uint32_t msgID)
{
auto it = m_UnconfirmedTagsMsgs.find (msgID);
if (it != m_UnconfirmedTagsMsgs.end ())
{
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
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;
}
}
bool GarlicRoutingSession::CleanupExpiredTags ()
{
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
for (auto it = m_SessionTags.begin (); it != m_SessionTags.end ();)
{
if (ts >= it->creationTime + OUTGOING_TAGS_EXPIRATION_TIMEOUT)
it = m_SessionTags.erase (it);
else
it++;
}
// delete expired unconfirmed tags
for (auto it = m_UnconfirmedTagsMsgs.begin (); it != m_UnconfirmedTagsMsgs.end ();)
{
if (ts >= it->second->tagsCreationTime + OUTGOING_TAGS_CONFIRMATION_TIMEOUT)
{
if (m_Owner)
m_Owner->RemoveDeliveryStatusSession (it->first);
delete it->second;
it = m_UnconfirmedTagsMsgs.erase (it);
}
else
it++;
}
return !m_SessionTags.empty () || !m_UnconfirmedTagsMsgs.empty ();
}
std::shared_ptr<I2NPMessage> GarlicRoutingSession::WrapSingleMessage (std::shared_ptr<const I2NPMessage> msg)
{
auto 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 (eLogWarning, "Garlic: No tags available. Use ElGamal");
if (!m_Destination)
{
LogPrint (eLogError, "Garlic: Can't use ElGamal for unknown destination");
return nullptr;
}
// create ElGamal block
ElGamalBlock elGamal;
memcpy (elGamal.sessionKey, m_SessionKey, 32);
RAND_bytes (elGamal.preIV, 32); // Pre-IV
uint8_t iv[32]; // IV is first 16 bytes
SHA256(elGamal.preIV, 32, iv);
m_ElGamalEncryption->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
SHA256(tag, 32, iv);
m_Encryption.SetIV (iv);
buf += 32;
len += 32;
}
// AES block
len += CreateAESBlock (buf, msg);
htobe32buf (m->GetPayload (), len);
m->len += len + 4;
m->FillI2NPMessageHeader (eI2NPGarlic);
return m;
}
size_t GarlicRoutingSession::CreateAESBlock (uint8_t * buf, std::shared_ptr<const I2NPMessage> msg)
{
size_t blockSize = 0;
bool createNewTags = m_Owner && m_NumTags && ((int)m_SessionTags.size () <= m_NumTags*2/3);
UnconfirmedTags * newTags = createNewTags ? GenerateSessionTags () : nullptr;
htobuf16 (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);
htobe32buf (payloadSize, len);
SHA256(buf + blockSize, len, payloadHash);
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, std::shared_ptr<const I2NPMessage> msg, UnconfirmedTags * newTags)
{
uint64_t ts = i2p::util::GetMillisecondsSinceEpoch () + 8000; // 8 sec
uint32_t msgID;
RAND_bytes ((uint8_t *)&msgID, 4);
size_t size = 0;
uint8_t * numCloves = payload + size;
*numCloves = 0;
size++;
if (m_Owner)
{
// resubmit non-confirmed LeaseSet
if (m_LeaseSetUpdateStatus == eLeaseSetSubmitted &&
i2p::util::GetMillisecondsSinceEpoch () > m_LeaseSetSubmissionTime + LEASET_CONFIRMATION_TIMEOUT)
m_LeaseSetUpdateStatus = eLeaseSetUpdated;
// attach DeviveryStatus if necessary
if (newTags || m_LeaseSetUpdateStatus == eLeaseSetUpdated) // new tags created or leaseset updated
{
// clove is DeliveryStatus
auto cloveSize = CreateDeliveryStatusClove (payload + size, msgID);
if (cloveSize > 0) // successive?
{
size += cloveSize;
(*numCloves)++;
if (newTags) // new tags created
m_UnconfirmedTagsMsgs[msgID] = newTags;
m_Owner->DeliveryStatusSent (shared_from_this (), msgID);
}
else
LogPrint (eLogWarning, "Garlic: DeliveryStatus clove was not created");
}
// attach LeaseSet
if (m_LeaseSetUpdateStatus == eLeaseSetUpdated)
{
m_LeaseSetUpdateStatus = eLeaseSetSubmitted;
m_LeaseSetUpdateMsgID = msgID;
m_LeaseSetSubmissionTime = i2p::util::GetMillisecondsSinceEpoch ();
// clove if our leaseSet must be attached
auto leaseSet = CreateDatabaseStoreMsg (m_Owner->GetLeaseSet ());
size += CreateGarlicClove (payload + size, leaseSet, false);
(*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;
htobe32buf (payload + size, msgID); // MessageID
size += 4;
htobe64buf (payload + size, ts); // Expiration of message
size += 8;
return size;
}
size_t GarlicRoutingSession::CreateGarlicClove (uint8_t * buf, std::shared_ptr<const I2NPMessage> msg, bool isDestination)
{
uint64_t ts = i2p::util::GetMillisecondsSinceEpoch () + 8000; // 8 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 cloveID;
RAND_bytes ((uint8_t *)&cloveID, 4);
htobe32buf (buf + size, cloveID); // CloveID
size += 4;
htobe64buf (buf + size, 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 inboundTunnel = m_Owner->GetTunnelPool ()->GetNextInboundTunnel ();
if (inboundTunnel)
{
buf[size] = eGarlicDeliveryTypeTunnel << 5; // delivery instructions flag tunnel
size++;
// hash and tunnelID sequence is reversed for Garlic
memcpy (buf + size, inboundTunnel->GetNextIdentHash (), 32); // To Hash
size += 32;
htobe32buf (buf + size, inboundTunnel->GetNextTunnelID ()); // tunnelID
size += 4;
// create msg
auto msg = CreateDeliveryStatusMsg (msgID);
if (m_Owner)
{
//encrypt
uint8_t key[32], tag[32];
RAND_bytes (key, 32); // random session key
RAND_bytes (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 ();
// fill clove
uint64_t ts = i2p::util::GetMillisecondsSinceEpoch () + 8000; // 8 sec
uint32_t cloveID;
RAND_bytes ((uint8_t *)&cloveID, 4);
htobe32buf (buf + size, cloveID); // CloveID
size += 4;
htobe64buf (buf + size, ts); // Expiration of clove
size += 8;
memset (buf + size, 0, 3); // certificate of clove
size += 3;
}
else
LogPrint (eLogError, "Garlic: No inbound tunnels in the pool for DeliveryStatus");
}
else
LogPrint (eLogWarning, "Garlic: Missing local LeaseSet");
return size;
}
GarlicDestination::~GarlicDestination ()
{
}
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 (std::shared_ptr<I2NPMessage> msg)
{
uint8_t * buf = msg->GetPayload ();
uint32_t length = bufbe32toh (buf);
if (length > msg->GetLength ())
{
LogPrint (eLogWarning, "Garlic: message length ", length, " exceeds I2NP message length ", msg->GetLength ());
return;
}
buf += 4; // length
auto it = m_Tags.find (SessionTag(buf));
if (it != m_Tags.end ())
{
// tag found. Use AES
if (length >= 32)
{
uint8_t iv[32]; // IV is first 16 bytes
SHA256(buf, 32, iv);
it->second->SetIV (iv);
it->second->Decrypt (buf + 32, length - 32, buf + 32);
HandleAESBlock (buf + 32, length - 32, it->second, msg->from);
}
else
LogPrint (eLogWarning, "Garlic: message length ", length, " is less than 32 bytes");
m_Tags.erase (it); // tag might be used only once
}
else
{
// tag not found. Use ElGamal
ElGamalBlock elGamal;
if (length >= 514 && 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
SHA256(elGamal.preIV, 32, iv);
decryption->SetIV (iv);
decryption->Decrypt(buf + 514, length - 514, buf + 514);
HandleAESBlock (buf + 514, length - 514, decryption, msg->from);
}
else
LogPrint (eLogError, "Garlic: Failed to decrypt message");
}
}
void GarlicDestination::HandleAESBlock (uint8_t * buf, size_t len, std::shared_ptr<i2p::crypto::CBCDecryption> decryption,
std::shared_ptr<i2p::tunnel::InboundTunnel> from)
{
uint16_t tagCount = bufbe16toh (buf);
buf += 2; len -= 2;
if (tagCount > 0)
{
if (tagCount*32 > len)
{
LogPrint (eLogError, "Garlic: 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 = bufbe32toh (buf);
if (payloadSize > len)
{
LogPrint (eLogError, "Garlic: 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 digest[32];
SHA256 (buf, payloadSize, digest);
if (memcmp (payloadHash, digest, 32)) // payload hash doesn't match
{
LogPrint (eLogError, "Garlic: wrong payload hash");
return;
}
HandleGarlicPayload (buf, payloadSize, from);
}
void GarlicDestination::HandleGarlicPayload (uint8_t * buf, size_t len, std::shared_ptr<i2p::tunnel::InboundTunnel> from)
{
const uint8_t * buf1 = buf;
int numCloves = buf[0];
LogPrint (eLogDebug, "Garlic: ", 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 (eLogWarning, "Garlic: clove encrypted");
buf += 32;
}
GarlicDeliveryType deliveryType = (GarlicDeliveryType)((flag >> 5) & 0x03);
switch (deliveryType)
{
case eGarlicDeliveryTypeLocal:
LogPrint (eLogDebug, "Garlic: type local");
HandleI2NPMessage (buf, len, from);
break;
case eGarlicDeliveryTypeDestination:
LogPrint (eLogDebug, "Garlic: type destination");
buf += 32; // destination. check it later or for multiple destinations
HandleI2NPMessage (buf, len, from);
break;
case eGarlicDeliveryTypeTunnel:
{
LogPrint (eLogDebug, "Garlic: type tunnel");
// gwHash and gwTunnel sequence is reverted
uint8_t * gwHash = buf;
buf += 32;
uint32_t gwTunnel = bufbe32toh (buf);
buf += 4;
std::shared_ptr<i2p::tunnel::OutboundTunnel> tunnel;
if (from && from->GetTunnelPool ())
tunnel = from->GetTunnelPool ()->GetNextOutboundTunnel ();
if (tunnel) // we have send it through an outbound tunnel
{
auto msg = CreateI2NPMessage (buf, GetI2NPMessageLength (buf), from);
tunnel->SendTunnelDataMsg (gwHash, gwTunnel, msg);
}
else
LogPrint (eLogWarning, "Garlic: No outbound tunnels available for garlic clove");
break;
}
case eGarlicDeliveryTypeRouter:
LogPrint (eLogWarning, "Garlic: type router not supported");
buf += 32;
break;
default:
LogPrint (eLogWarning, "Garlic: unknown delivery type ", (int)deliveryType);
}
buf += GetI2NPMessageLength (buf); // I2NP
buf += 4; // CloveID
buf += 8; // Date
buf += 3; // Certificate
if (buf - buf1 > (int)len)
{
LogPrint (eLogError, "Garlic: clove is too long");
break;
}
}
}
std::shared_ptr<I2NPMessage> GarlicDestination::WrapMessage (std::shared_ptr<const i2p::data::RoutingDestination> destination,
std::shared_ptr<I2NPMessage> msg, bool attachLeaseSet)
{
auto session = GetRoutingSession (destination, attachLeaseSet);
return session->WrapSingleMessage (msg);
}
std::shared_ptr<GarlicRoutingSession> GarlicDestination::GetRoutingSession (
std::shared_ptr<const i2p::data::RoutingDestination> destination, bool attachLeaseSet)
{
GarlicRoutingSessionPtr session;
{
std::unique_lock<std::mutex> l(m_SessionsMutex);
auto it = m_Sessions.find (destination->GetIdentHash ());
if (it != m_Sessions.end ())
session = it->second;
}
if (!session)
{
session = std::make_shared<GarlicRoutingSession> (this, destination,
attachLeaseSet ? m_NumTags : 4, attachLeaseSet); // specified num tags for connections and 4 for LS requests
std::unique_lock<std::mutex> l(m_SessionsMutex);
m_Sessions[destination->GetIdentHash ()] = session;
}
return session;
}
void GarlicDestination::CleanupExpiredTags ()
{
// incoming
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
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++;
}
if (numExpiredTags > 0)
LogPrint (eLogDebug, "Garlic: ", numExpiredTags, " tags expired for ", GetIdentHash().ToBase64 ());
// outgoing
std::unique_lock<std::mutex> l(m_SessionsMutex);
for (auto it = m_Sessions.begin (); it != m_Sessions.end ();)
{
if (!it->second->CleanupExpiredTags ())
{
LogPrint (eLogInfo, "Routing session to ", it->first.ToBase32 (), " deleted");
it = m_Sessions.erase (it);
}
else
it++;
}
}
void GarlicDestination::RemoveDeliveryStatusSession (uint32_t msgID)
{
m_DeliveryStatusSessions.erase (msgID);
}
void GarlicDestination::DeliveryStatusSent (GarlicRoutingSessionPtr session, uint32_t msgID)
{
m_DeliveryStatusSessions[msgID] = session;
}
void GarlicDestination::HandleDeliveryStatusMessage (std::shared_ptr<I2NPMessage> msg)
{
uint32_t msgID = bufbe32toh (msg->GetPayload ());
{
auto it = m_DeliveryStatusSessions.find (msgID);
if (it != m_DeliveryStatusSessions.end ())
{
it->second->MessageConfirmed (msgID);
m_DeliveryStatusSessions.erase (it);
LogPrint (eLogDebug, "Garlic: message ", msgID, " acknowledged");
}
}
}
void GarlicDestination::SetLeaseSetUpdated ()
{
std::unique_lock<std::mutex> l(m_SessionsMutex);
for (auto it: m_Sessions)
it.second->SetLeaseSetUpdated ();
}
void GarlicDestination::ProcessGarlicMessage (std::shared_ptr<I2NPMessage> msg)
{
HandleGarlicMessage (msg);
}
void GarlicDestination::ProcessDeliveryStatusMessage (std::shared_ptr<I2NPMessage> msg)
{
HandleDeliveryStatusMessage (msg);
}
}
}
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