I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <string.h>
#include "I2PEndian.h"
#include "Crypto.h"
#include "Log.h"
#include "Timestamp.h"
#include "NetDb.hpp"
#include "Tunnel.h"
#include "LeaseSet.h"
namespace i2p
{
namespace data
{
LeaseSet::LeaseSet (const uint8_t * buf, size_t len, bool storeLeases):
m_IsValid (true), m_StoreLeases (storeLeases), m_ExpirationTime (0)
{
m_Buffer = new uint8_t[len];
memcpy (m_Buffer, buf, len);
m_BufferLen = len;
ReadFromBuffer ();
}
void LeaseSet::Update (const uint8_t * buf, size_t len, bool verifySignature)
{
if (len > m_BufferLen)
{
auto oldBuffer = m_Buffer;
m_Buffer = new uint8_t[len];
delete[] oldBuffer;
}
memcpy (m_Buffer, buf, len);
m_BufferLen = len;
ReadFromBuffer (false, verifySignature);
}
void LeaseSet::PopulateLeases ()
{
m_StoreLeases = true;
ReadFromBuffer (false);
}
void LeaseSet::ReadFromBuffer (bool readIdentity, bool verifySignature)
{
if (readIdentity || !m_Identity)
m_Identity = std::make_shared<IdentityEx>(m_Buffer, m_BufferLen);
size_t size = m_Identity->GetFullLen ();
if (size > m_BufferLen)
{
LogPrint (eLogError, "LeaseSet: identity length ", size, " exceeds buffer size ", m_BufferLen);
m_IsValid = false;
return;
}
memcpy (m_EncryptionKey, m_Buffer + size, 256);
size += 256; // encryption key
size += m_Identity->GetSigningPublicKeyLen (); // unused signing key
uint8_t num = m_Buffer[size];
size++; // num
LogPrint (eLogDebug, "LeaseSet: read num=", (int)num);
if (!num || num > MAX_NUM_LEASES)
{
LogPrint (eLogError, "LeaseSet: incorrect number of leases", (int)num);
m_IsValid = false;
return;
}
// reset existing leases
if (m_StoreLeases)
for (auto& it: m_Leases)
it->isUpdated = false;
else
m_Leases.clear ();
// process leases
m_ExpirationTime = 0;
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
const uint8_t * leases = m_Buffer + size;
for (int i = 0; i < num; i++)
{
Lease lease;
lease.tunnelGateway = leases;
leases += 32; // gateway
lease.tunnelID = bufbe32toh (leases);
leases += 4; // tunnel ID
lease.endDate = bufbe64toh (leases);
leases += 8; // end date
if (ts < lease.endDate + LEASE_ENDDATE_THRESHOLD)
{
if (lease.endDate > m_ExpirationTime)
m_ExpirationTime = lease.endDate;
if (m_StoreLeases)
{
auto ret = m_Leases.insert (std::make_shared<Lease>(lease));
if (!ret.second) (*ret.first)->endDate = lease.endDate; // update existing
(*ret.first)->isUpdated = true;
// check if lease's gateway is in our netDb
if (!netdb.FindRouter (lease.tunnelGateway))
{
// if not found request it
LogPrint (eLogInfo, "LeaseSet: Lease's tunnel gateway not found, requesting");
netdb.RequestDestination (lease.tunnelGateway);
}
}
}
else
LogPrint (eLogWarning, "LeaseSet: Lease is expired already ");
}
if (!m_ExpirationTime)
{
LogPrint (eLogWarning, "LeaseSet: all leases are expired. Dropped");
m_IsValid = false;
return;
}
m_ExpirationTime += LEASE_ENDDATE_THRESHOLD;
// delete old leases
if (m_StoreLeases)
{
for (auto it = m_Leases.begin (); it != m_Leases.end ();)
{
if (!(*it)->isUpdated)
{
(*it)->endDate = 0; // somebody might still hold it
m_Leases.erase (it++);
}
else
++it;
}
}
// verify
if (verifySignature && !m_Identity->Verify (m_Buffer, leases - m_Buffer, leases))
{
LogPrint (eLogWarning, "LeaseSet: verification failed");
m_IsValid = false;
}
}
uint64_t LeaseSet::ExtractTimestamp (const uint8_t * buf, size_t len) const
{
if (!m_Identity) return 0;
size_t size = m_Identity->GetFullLen ();
if (size > len) return 0;
size += 256; // encryption key
size += m_Identity->GetSigningPublicKeyLen (); // unused signing key
if (size > len) return 0;
uint8_t num = buf[size];
size++; // num
if (size + num*LEASE_SIZE > len) return 0;
uint64_t timestamp= 0 ;
for (int i = 0; i < num; i++)
{
size += 36; // gateway (32) + tunnelId(4)
auto endDate = bufbe64toh (buf + size);
size += 8; // end date
if (!timestamp || endDate < timestamp)
timestamp = endDate;
}
return timestamp;
}
bool LeaseSet::IsNewer (const uint8_t * buf, size_t len) const
{
return ExtractTimestamp (buf, len) > ExtractTimestamp (m_Buffer, m_BufferLen);
}
bool LeaseSet::ExpiresSoon(const uint64_t dlt, const uint64_t fudge) const
{
auto now = i2p::util::GetMillisecondsSinceEpoch ();
if (fudge) now += rand() % fudge;
if (now >= m_ExpirationTime) return true;
return m_ExpirationTime - now <= dlt;
}
const std::vector<std::shared_ptr<const Lease> > LeaseSet::GetNonExpiredLeases (bool withThreshold) const
{
return GetNonExpiredLeasesExcluding( [] (const Lease & l) -> bool { return false; }, withThreshold);
}
const std::vector<std::shared_ptr<const Lease> > LeaseSet::GetNonExpiredLeasesExcluding (LeaseInspectFunc exclude, bool withThreshold) const
{
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
std::vector<std::shared_ptr<const Lease> > leases;
for (const auto& it: m_Leases)
{
auto endDate = it->endDate;
if (withThreshold)
endDate += LEASE_ENDDATE_THRESHOLD;
else
endDate -= LEASE_ENDDATE_THRESHOLD;
if (ts < endDate && !exclude(*it))
leases.push_back (it);
}
return leases;
}
bool LeaseSet::HasExpiredLeases () const
{
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
for (const auto& it: m_Leases)
if (ts >= it->endDate) return true;
return false;
}
bool LeaseSet::IsExpired () const
{
if (m_StoreLeases && IsEmpty ()) return true;
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
return ts > m_ExpirationTime;
}
void LeaseSet::Encrypt (const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx) const
{
auto encryptor = m_Identity->CreateEncryptor (m_EncryptionKey);
if (encryptor)
encryptor->Encrypt (data, encrypted, ctx);
}
LocalLeaseSet::LocalLeaseSet (std::shared_ptr<const IdentityEx> identity, const uint8_t * encryptionPublicKey, std::vector<std::shared_ptr<i2p::tunnel::InboundTunnel> > tunnels):
m_ExpirationTime (0), m_Identity (identity)
{
int num = tunnels.size ();
if (num > MAX_NUM_LEASES) num = MAX_NUM_LEASES;
// identity
auto signingKeyLen = m_Identity->GetSigningPublicKeyLen ();
m_BufferLen = m_Identity->GetFullLen () + 256 + signingKeyLen + 1 + num*LEASE_SIZE + m_Identity->GetSignatureLen ();
m_Buffer = new uint8_t[m_BufferLen];
auto offset = m_Identity->ToBuffer (m_Buffer, m_BufferLen);
memcpy (m_Buffer + offset, encryptionPublicKey, 256);
offset += 256;
memset (m_Buffer + offset, 0, signingKeyLen);
offset += signingKeyLen;
// num leases
m_Buffer[offset] = num;
offset++;
// leases
m_Leases = m_Buffer + offset;
auto currentTime = i2p::util::GetMillisecondsSinceEpoch ();
for (int i = 0; i < num; i++)
{
memcpy (m_Buffer + offset, tunnels[i]->GetNextIdentHash (), 32);
offset += 32; // gateway id
htobe32buf (m_Buffer + offset, tunnels[i]->GetNextTunnelID ());
offset += 4; // tunnel id
uint64_t ts = tunnels[i]->GetCreationTime () + i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT - i2p::tunnel::TUNNEL_EXPIRATION_THRESHOLD; // 1 minute before expiration
ts *= 1000; // in milliseconds
if (ts > m_ExpirationTime) m_ExpirationTime = ts;
// make sure leaseset is newer than previous, but adding some time to expiration date
ts += (currentTime - tunnels[i]->GetCreationTime ()*1000LL)*2/i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT; // up to 2 secs
htobe64buf (m_Buffer + offset, ts);
offset += 8; // end date
}
// we don't sign it yet. must be signed later on
}
LocalLeaseSet::LocalLeaseSet (std::shared_ptr<const IdentityEx> identity, const uint8_t * buf, size_t len):
m_ExpirationTime (0), m_Identity (identity)
{
m_BufferLen = len;
m_Buffer = new uint8_t[m_BufferLen];
memcpy (m_Buffer, buf, len);
}
bool LocalLeaseSet::IsExpired () const
{
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
return ts > m_ExpirationTime;
}
bool LeaseSetBufferValidate(const uint8_t * ptr, size_t sz, uint64_t & expires)
{
IdentityEx ident(ptr, sz);
size_t size = ident.GetFullLen ();
if (size > sz)
{
LogPrint (eLogError, "LeaseSet: identity length ", size, " exceeds buffer size ", sz);
return false;
}
// encryption key
size += 256;
// signing key (unused)
size += ident.GetSigningPublicKeyLen ();
uint8_t numLeases = ptr[size];
++size;
if (!numLeases || numLeases > MAX_NUM_LEASES)
{
LogPrint (eLogError, "LeaseSet: incorrect number of leases", (int)numLeases);
return false;
}
const uint8_t * leases = ptr + size;
expires = 0;
/** find lease with the max expiration timestamp */
for (int i = 0; i < numLeases; i++)
{
leases += 36; // gateway + tunnel ID
uint64_t endDate = bufbe64toh (leases);
leases += 8; // end date
if(endDate > expires)
expires = endDate;
}
return ident.Verify(ptr, leases - ptr, leases);
}
}
}