I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <string.h>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <zlib.h> // for crc32
#include "I2PEndian.h"
#include "Crypto.h"
#include "Ed25519.h"
#include "Log.h"
#include "Timestamp.h"
#include "NetDb.hpp"
#include "Tunnel.h"
#include "LeaseSet.h"
namespace i2p
{
namespace data
{
LeaseSet::LeaseSet (bool storeLeases):
m_IsValid (false), m_StoreLeases (storeLeases), m_ExpirationTime (0), m_EncryptionKey (nullptr),
m_Buffer (nullptr), m_BufferLen (0)
{
}
LeaseSet::LeaseSet (const uint8_t * buf, size_t len, bool storeLeases):
m_IsValid (true), m_StoreLeases (storeLeases), m_ExpirationTime (0), m_EncryptionKey (nullptr)
{
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;
}
if (m_StoreLeases)
{
if (!m_EncryptionKey) m_EncryptionKey = new uint8_t[256];
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;
}
UpdateLeasesBegin ();
// 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
UpdateLease (lease, ts);
}
if (!m_ExpirationTime)
{
LogPrint (eLogWarning, "LeaseSet: all leases are expired. Dropped");
m_IsValid = false;
return;
}
m_ExpirationTime += LEASE_ENDDATE_THRESHOLD;
UpdateLeasesEnd ();
// verify
if (verifySignature && !m_Identity->Verify (m_Buffer, leases - m_Buffer, leases))
{
LogPrint (eLogWarning, "LeaseSet: verification failed");
m_IsValid = false;
}
}
void LeaseSet::UpdateLeasesBegin ()
{
// reset existing leases
if (m_StoreLeases)
for (auto& it: m_Leases)
it->isUpdated = false;
else
m_Leases.clear ();
}
void LeaseSet::UpdateLeasesEnd ()
{
// 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;
}
}
}
void LeaseSet::UpdateLease (const Lease& lease, uint64_t ts)
{
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 ");
}
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
{
if (!m_EncryptionKey) return;
auto encryptor = m_Identity->CreateEncryptor (m_EncryptionKey);
if (encryptor)
encryptor->Encrypt (data, encrypted, ctx, true);
}
void LeaseSet::SetBuffer (const uint8_t * buf, size_t len)
{
if (m_Buffer) delete[] m_Buffer;
m_Buffer = new uint8_t[len];
m_BufferLen = len;
memcpy (m_Buffer, buf, len);
}
BlindedPublicKey::BlindedPublicKey (std::shared_ptr<const IdentityEx> identity, SigningKeyType blindedKeyType):
m_BlindedSigType (blindedKeyType)
{
if (!identity) return;
auto len = identity->GetSigningPublicKeyLen ();
m_PublicKey.resize (len);
memcpy (m_PublicKey.data (), identity->GetSigningPublicKeyBuffer (), len);
m_SigType = identity->GetSigningKeyType ();
}
BlindedPublicKey::BlindedPublicKey (const std::string& b33)
{
uint8_t addr[40]; // TODO: define length from b33
size_t l = i2p::data::Base32ToByteStream (b33.c_str (), b33.length (), addr, 40);
uint32_t checksum = crc32 (0, addr + 3, l - 3);
// checksum is Little Endian
addr[0] ^= checksum; addr[1] ^= (checksum >> 8); addr[2] ^= (checksum >> 16);
uint8_t flag = addr[0];
size_t offset = 1;
if (flag & 0x01) // two bytes signatures
{
m_SigType = bufbe16toh (addr + offset); offset += 2;
m_BlindedSigType = bufbe16toh (addr + offset); offset += 2;
}
else // one byte sig
{
m_SigType = addr[offset]; offset++;
m_BlindedSigType = addr[offset]; offset++;
}
std::unique_ptr<i2p::crypto::Verifier> blindedVerifier (i2p::data::IdentityEx::CreateVerifier (m_SigType));
if (blindedVerifier)
{
auto len = blindedVerifier->GetPublicKeyLen ();
if (offset + len <= l)
{
m_PublicKey.resize (len);
memcpy (m_PublicKey.data (), addr + offset, len);
}
else
LogPrint (eLogError, "LeaseSet2: public key in b33 address is too short for signature type ", (int)m_SigType);
}
else
LogPrint (eLogError, "LeaseSet2: unknown signature type ", (int)m_SigType, " in b33");
}
std::string BlindedPublicKey::ToB33 () const
{
if (m_PublicKey.size () > 32) return ""; // assume 25519
uint8_t addr[35]; char str[60]; // TODO: define actual length
addr[0] = 0; // flags
addr[1] = m_SigType; // sig type
addr[2] = m_BlindedSigType; // blinded sig type
memcpy (addr + 3, m_PublicKey.data (), m_PublicKey.size ());
uint32_t checksum = crc32 (0, addr + 3, m_PublicKey.size ());
// checksum is Little Endian
addr[0] ^= checksum; addr[1] ^= (checksum >> 8); addr[2] ^= (checksum >> 16);
auto l = ByteStreamToBase32 (addr, m_PublicKey.size () + 3, str, 60);
return std::string (str, str + l);
}
void BlindedPublicKey::GetCredential (uint8_t * credential) const
{
// A = destination's signing public key
// stA = signature type of A, 2 bytes big endian
uint16_t stA = htobe16 (GetSigType ());
// stA1 = signature type of blinded A, 2 bytes big endian
uint16_t stA1 = htobe16 (GetBlindedSigType ());
// credential = H("credential", A || stA || stA1)
H ("credential", { {GetPublicKey (), GetPublicKeyLen ()}, {(const uint8_t *)&stA, 2}, {(const uint8_t *)&stA1, 2} }, credential);
}
void BlindedPublicKey::GetSubcredential (const uint8_t * blinded, size_t len, uint8_t * subcredential) const
{
uint8_t credential[32];
GetCredential (credential);
// subcredential = H("subcredential", credential || blindedPublicKey)
H ("subcredential", { {credential, 32}, {blinded, len} }, subcredential);
}
void BlindedPublicKey::GenerateAlpha (const char * date, uint8_t * seed) const
{
uint16_t stA = htobe16 (GetSigType ()), stA1 = htobe16 (GetBlindedSigType ());
uint8_t salt[32];
//seed = HKDF(H("I2PGenerateAlpha", keydata), datestring || secret, "i2pblinding1", 64)
H ("I2PGenerateAlpha", { {GetPublicKey (), GetPublicKeyLen ()}, {(const uint8_t *)&stA, 2}, {(const uint8_t *)&stA1, 2} }, salt);
i2p::crypto::HKDF (salt, (const uint8_t *)date, 8, "i2pblinding1", seed);
}
void BlindedPublicKey::GetBlindedKey (const char * date, uint8_t * blindedKey) const
{
uint8_t seed[64];
GenerateAlpha (date, seed);
i2p::crypto::GetEd25519 ()->BlindPublicKey (GetPublicKey (), seed, blindedKey);
}
void BlindedPublicKey::BlindPrivateKey (const uint8_t * priv, const char * date, uint8_t * blindedPriv, uint8_t * blindedPub) const
{
uint8_t seed[64];
GenerateAlpha (date, seed);
i2p::crypto::GetEd25519 ()->BlindPrivateKey (priv, seed, blindedPriv, blindedPub);
}
void BlindedPublicKey::H (const std::string& p, const std::vector<std::pair<const uint8_t *, size_t> >& bufs, uint8_t * hash) const
{
SHA256_CTX ctx;
SHA256_Init (&ctx);
SHA256_Update (&ctx, p.c_str (), p.length ());
for (const auto& it: bufs)
SHA256_Update (&ctx, it.first, it.second);
SHA256_Final (hash, &ctx);
}
i2p::data::IdentHash BlindedPublicKey::GetStoreHash (const char * date) const
{
i2p::data::IdentHash hash;
if (m_BlindedSigType == i2p::data::SIGNING_KEY_TYPE_REDDSA_SHA512_ED25519 ||
m_BlindedSigType == SIGNING_KEY_TYPE_EDDSA_SHA512_ED25519)
{
uint8_t blinded[32];
if (date)
GetBlindedKey (date, blinded);
else
{
char currentDate[9];
i2p::util::GetCurrentDate (currentDate);
GetBlindedKey (currentDate, blinded);
}
auto stA1 = htobe16 (m_BlindedSigType);
SHA256_CTX ctx;
SHA256_Init (&ctx);
SHA256_Update (&ctx, (const uint8_t *)&stA1, 2);
SHA256_Update (&ctx, blinded, 32);
SHA256_Final ((uint8_t *)hash, &ctx);
}
else
LogPrint (eLogError, "LeaseSet2: blinded key type ", (int)m_BlindedSigType, " is not supported");
return hash;
}
LeaseSet2::LeaseSet2 (uint8_t storeType, const uint8_t * buf, size_t len, bool storeLeases):
LeaseSet (storeLeases), m_StoreType (storeType), m_OrigStoreType (storeType)
{
SetBuffer (buf, len);
if (storeType == NETDB_STORE_TYPE_ENCRYPTED_LEASESET2)
ReadFromBufferEncrypted (buf, len, nullptr);
else
ReadFromBuffer (buf, len);
}
LeaseSet2::LeaseSet2 (const uint8_t * buf, size_t len, std::shared_ptr<const BlindedPublicKey> key):
LeaseSet (true), m_StoreType (NETDB_STORE_TYPE_ENCRYPTED_LEASESET2), m_OrigStoreType (NETDB_STORE_TYPE_ENCRYPTED_LEASESET2)
{
ReadFromBufferEncrypted (buf, len, key);
}
void LeaseSet2::Update (const uint8_t * buf, size_t len, bool verifySignature)
{
SetBuffer (buf, len);
if (GetStoreType () != NETDB_STORE_TYPE_ENCRYPTED_LEASESET2)
ReadFromBuffer (buf, len, false, verifySignature);
// TODO: implement encrypted
}
void LeaseSet2::ReadFromBuffer (const uint8_t * buf, size_t len, bool readIdentity, bool verifySignature)
{
// standard LS2 header
std::shared_ptr<const IdentityEx> identity;
if (readIdentity)
{
identity = std::make_shared<IdentityEx>(buf, len);
SetIdentity (identity);
}
else
identity = GetIdentity ();
size_t offset = identity->GetFullLen ();
if (offset + 8 >= len) return;
m_PublishedTimestamp = bufbe32toh (buf + offset); offset += 4; // published timestamp (seconds)
uint16_t expires = bufbe16toh (buf + offset); offset += 2; // expires (seconds)
SetExpirationTime ((m_PublishedTimestamp + expires)*1000LL); // in milliseconds
uint16_t flags = bufbe16toh (buf + offset); offset += 2; // flags
if (flags & LEASESET2_FLAG_OFFLINE_KEYS)
{
// transient key
m_TransientVerifier = ProcessOfflineSignature (identity, buf, len, offset);
if (!m_TransientVerifier)
{
LogPrint (eLogError, "LeaseSet2: offline signature failed");
return;
}
}
// type specific part
size_t s = 0;
switch (m_StoreType)
{
case NETDB_STORE_TYPE_STANDARD_LEASESET2:
s = ReadStandardLS2TypeSpecificPart (buf + offset, len - offset);
break;
case NETDB_STORE_TYPE_META_LEASESET2:
s = ReadMetaLS2TypeSpecificPart (buf + offset, len - offset);
break;
default:
LogPrint (eLogWarning, "LeaseSet2: Unexpected store type ", (int)m_StoreType);
}
if (!s) return;
offset += s;
if (verifySignature || m_TransientVerifier)
{
// verify signature
bool verified = m_TransientVerifier ? VerifySignature (m_TransientVerifier, buf, len, offset) :
VerifySignature (identity, buf, len, offset);
SetIsValid (verified);
}
}
template<typename Verifier>
bool LeaseSet2::VerifySignature (Verifier& verifier, const uint8_t * buf, size_t len, size_t signatureOffset)
{
if (signatureOffset + verifier->GetSignatureLen () > len) return false;
// we assume buf inside DatabaseStore message, so buf[-1] is valid memory
// change it for signature verification, and restore back
uint8_t c = buf[-1];
const_cast<uint8_t *>(buf)[-1] = m_StoreType;
bool verified = verifier->Verify (buf - 1, signatureOffset + 1, buf + signatureOffset);
const_cast<uint8_t *>(buf)[-1] = c;
if (!verified)
LogPrint (eLogWarning, "LeaseSet2: verification failed");
return verified;
}
size_t LeaseSet2::ReadStandardLS2TypeSpecificPart (const uint8_t * buf, size_t len)
{
size_t offset = 0;
// properties
uint16_t propertiesLen = bufbe16toh (buf + offset); offset += 2;
offset += propertiesLen; // skip for now. TODO: implement properties
if (offset + 1 >= len) return 0;
// key sections
uint16_t currentKeyType = 0;
int numKeySections = buf[offset]; offset++;
for (int i = 0; i < numKeySections; i++)
{
uint16_t keyType = bufbe16toh (buf + offset); offset += 2; // encryption key type
if (offset + 2 >= len) return 0;
uint16_t encryptionKeyLen = bufbe16toh (buf + offset); offset += 2;
if (offset + encryptionKeyLen >= len) return 0;
if (IsStoreLeases ()) // create encryptor with leases only
{
// we pick first valid key, higher key type has higher priority 4-1-0
// if two keys with of the same type, pick first
auto encryptor = i2p::data::IdentityEx::CreateEncryptor (keyType, buf + offset);
if (encryptor && (!m_Encryptor || keyType > currentKeyType))
{
m_Encryptor = encryptor; // TODO: atomic
currentKeyType = keyType;
}
}
offset += encryptionKeyLen;
}
// leases
if (offset + 1 >= len) return 0;
int numLeases = buf[offset]; offset++;
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
if (IsStoreLeases ())
{
UpdateLeasesBegin ();
for (int i = 0; i < numLeases; i++)
{
if (offset + LEASE2_SIZE > len) return 0;
Lease lease;
lease.tunnelGateway = buf + offset; offset += 32; // gateway
lease.tunnelID = bufbe32toh (buf + offset); offset += 4; // tunnel ID
lease.endDate = bufbe32toh (buf + offset)*1000LL; offset += 4; // end date
UpdateLease (lease, ts);
}
UpdateLeasesEnd ();
}
else
offset += numLeases*LEASE2_SIZE; // 40 bytes per lease
return offset;
}
size_t LeaseSet2::ReadMetaLS2TypeSpecificPart (const uint8_t * buf, size_t len)
{
size_t offset = 0;
// properties
uint16_t propertiesLen = bufbe16toh (buf + offset); offset += 2;
offset += propertiesLen; // skip for now. TODO: implement properties
// entries
if (offset + 1 >= len) return 0;
int numEntries = buf[offset]; offset++;
for (int i = 0; i < numEntries; i++)
{
if (offset + 40 >= len) return 0;
offset += 32; // hash
offset += 3; // flags
offset += 1; // cost
offset += 4; // expires
}
// revocations
if (offset + 1 >= len) return 0;
int numRevocations = buf[offset]; offset++;
for (int i = 0; i < numRevocations; i++)
{
if (offset + 32 > len) return 0;
offset += 32; // hash
}
return offset;
}
void LeaseSet2::ReadFromBufferEncrypted (const uint8_t * buf, size_t len, std::shared_ptr<const BlindedPublicKey> key)
{
size_t offset = 0;
// blinded key
if (len < 2) return;
const uint8_t * stA1 = buf + offset; // stA1 = blinded signature type, 2 bytes big endian
uint16_t blindedKeyType = bufbe16toh (stA1); offset += 2;
std::unique_ptr<i2p::crypto::Verifier> blindedVerifier (i2p::data::IdentityEx::CreateVerifier (blindedKeyType));
if (!blindedVerifier) return;
auto blindedKeyLen = blindedVerifier->GetPublicKeyLen ();
if (offset + blindedKeyLen >= len) return;
const uint8_t * blindedPublicKey = buf + offset;
blindedVerifier->SetPublicKey (blindedPublicKey); offset += blindedKeyLen;
// expiration
if (offset + 8 >= len) return;
const uint8_t * publishedTimestamp = buf + offset;
m_PublishedTimestamp = bufbe32toh (publishedTimestamp); offset += 4; // published timestamp (seconds)
uint16_t expires = bufbe16toh (buf + offset); offset += 2; // expires (seconds)
SetExpirationTime ((m_PublishedTimestamp + expires)*1000LL); // in milliseconds
uint16_t flags = bufbe16toh (buf + offset); offset += 2; // flags
if (flags & LEASESET2_FLAG_OFFLINE_KEYS)
{
// transient key
m_TransientVerifier = ProcessOfflineSignature (blindedVerifier, buf, len, offset);
if (!m_TransientVerifier)
{
LogPrint (eLogError, "LeaseSet2: offline signature failed");
return;
}
}
// outer ciphertext
if (offset + 2 > len) return;
uint16_t lenOuterCiphertext = bufbe16toh (buf + offset); offset += 2;
const uint8_t * outerCiphertext = buf + offset;
offset += lenOuterCiphertext;
// verify signature
bool verified = m_TransientVerifier ? VerifySignature (m_TransientVerifier, buf, len, offset) :
VerifySignature (blindedVerifier, buf, len, offset);
SetIsValid (verified);
// handle ciphertext
if (verified && key && lenOuterCiphertext >= 32)
{
SetIsValid (false); // we must verify it again in Layer 2
if (blindedKeyType == i2p::data::SIGNING_KEY_TYPE_REDDSA_SHA512_ED25519)
{
// verify blinding
char date[9];
i2p::util::GetDateString (m_PublishedTimestamp, date);
uint8_t blinded[32];
key->GetBlindedKey (date, blinded);
if (memcmp (blindedPublicKey, blinded, 32))
{
LogPrint (eLogError, "LeaseSet2: blinded public key doesn't match");
return;
}
}
// outer key
// outerInput = subcredential || publishedTimestamp
uint8_t subcredential[36];
key->GetSubcredential (blindedPublicKey, blindedKeyLen, subcredential);
memcpy (subcredential + 32, publishedTimestamp, 4);
// outerSalt = outerCiphertext[0:32]
// keys = HKDF(outerSalt, outerInput, "ELS2_L1K", 44)
uint8_t keys[64]; // 44 bytes actual data
i2p::crypto::HKDF (outerCiphertext, subcredential, 36, "ELS2_L1K", keys);
// decrypt Layer 1
// outerKey = keys[0:31]
// outerIV = keys[32:43]
size_t lenOuterPlaintext = lenOuterCiphertext - 32;
std::vector<uint8_t> outerPlainText (lenOuterPlaintext);
i2p::crypto::ChaCha20 (outerCiphertext + 32, lenOuterPlaintext, keys, keys + 32, outerPlainText.data ());
// inner key
// innerInput = authCookie || subcredential || publishedTimestamp, TODO: non-empty authCookie
// innerSalt = innerCiphertext[0:32]
// keys = HKDF(innerSalt, innerInput, "ELS2_L2K", 44)
// skip 1 byte flags
i2p::crypto::HKDF (outerPlainText.data () + 1, subcredential, 36, "ELS2_L2K", keys); // no authCookie
// decrypt Layer 2
// innerKey = keys[0:31]
// innerIV = keys[32:43]
size_t lenInnerPlaintext = lenOuterPlaintext - 32 - 1;
std::vector<uint8_t> innerPlainText (lenInnerPlaintext);
i2p::crypto::ChaCha20 (outerPlainText.data () + 32 + 1, lenInnerPlaintext, keys, keys + 32, innerPlainText.data ());
if (innerPlainText[0] == NETDB_STORE_TYPE_STANDARD_LEASESET2 || innerPlainText[0] == NETDB_STORE_TYPE_META_LEASESET2)
{
// override store type and buffer
m_StoreType = innerPlainText[0];
SetBuffer (innerPlainText.data () + 1, lenInnerPlaintext - 1);
// parse and verify Layer 2
ReadFromBuffer (innerPlainText.data () + 1, lenInnerPlaintext - 1);
}
else
LogPrint (eLogError, "LeaseSet2: unexpected LeaseSet type ", (int)innerPlainText[0], " inside encrypted LeaseSet");
}
}
void LeaseSet2::Encrypt (const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx) const
{
auto encryptor = m_Encryptor; // TODO: atomic
if (encryptor)
encryptor->Encrypt (data, encrypted, ctx, true);
}
uint64_t LeaseSet2::ExtractTimestamp (const uint8_t * buf, size_t len) const
{
if (len < 8) return 0;
if (m_StoreType == NETDB_STORE_TYPE_ENCRYPTED_LEASESET2)
{
// encrypted LS2
size_t offset = 0;
uint16_t blindedKeyType = bufbe16toh (buf + offset); offset += 2;
std::unique_ptr<i2p::crypto::Verifier> blindedVerifier (i2p::data::IdentityEx::CreateVerifier (blindedKeyType));
if (!blindedVerifier) return 0 ;
auto blindedKeyLen = blindedVerifier->GetPublicKeyLen ();
if (offset + blindedKeyLen + 6 >= len) return 0;
offset += blindedKeyLen;
uint32_t timestamp = bufbe32toh (buf + offset); offset += 4;
uint16_t expires = bufbe16toh (buf + offset); offset += 2;
return (timestamp + expires)* 1000LL;
}
else
{
auto identity = GetIdentity ();
if (!identity) return 0;
size_t offset = identity->GetFullLen ();
if (offset + 6 >= len) return 0;
uint32_t timestamp = bufbe32toh (buf + offset); offset += 4;
uint16_t expires = bufbe16toh (buf + offset); offset += 2;
return (timestamp + expires)* 1000LL;
}
}
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)
{
if (buf)
{
m_BufferLen = len;
m_Buffer = new uint8_t[m_BufferLen];
memcpy (m_Buffer, buf, len);
}
else
{
m_Buffer = nullptr;
m_BufferLen = 0;
}
}
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);
}
LocalLeaseSet2::LocalLeaseSet2 (uint8_t storeType, const i2p::data::PrivateKeys& keys,
uint16_t keyType, uint16_t keyLen, const uint8_t * encryptionPublicKey,
std::vector<std::shared_ptr<i2p::tunnel::InboundTunnel> > tunnels):
LocalLeaseSet (keys.GetPublic (), nullptr, 0)
{
auto identity = keys.GetPublic ();
// assume standard LS2
int num = tunnels.size ();
if (num > MAX_NUM_LEASES) num = MAX_NUM_LEASES;
m_BufferLen = identity->GetFullLen () + 4/*published*/ + 2/*expires*/ + 2/*flag*/ + 2/*properties len*/ +
1/*num keys*/ + 2/*key type*/ + 2/*key len*/ + keyLen/*key*/ + 1/*num leases*/ + num*LEASE2_SIZE + keys.GetSignatureLen ();
uint16_t flags = 0;
if (keys.IsOfflineSignature ())
{
flags |= LEASESET2_FLAG_OFFLINE_KEYS;
m_BufferLen += keys.GetOfflineSignature ().size ();
}
m_Buffer = new uint8_t[m_BufferLen + 1];
m_Buffer[0] = storeType;
// LS2 header
auto offset = identity->ToBuffer (m_Buffer + 1, m_BufferLen) + 1;
auto timestamp = i2p::util::GetSecondsSinceEpoch ();
htobe32buf (m_Buffer + offset, timestamp); offset += 4; // published timestamp (seconds)
uint8_t * expiresBuf = m_Buffer + offset; offset += 2; // expires, fill later
htobe16buf (m_Buffer + offset, flags); offset += 2; // flags
if (keys.IsOfflineSignature ())
{
// offline signature
const auto& offlineSignature = keys.GetOfflineSignature ();
memcpy (m_Buffer + offset, offlineSignature.data (), offlineSignature.size ());
offset += offlineSignature.size ();
}
htobe16buf (m_Buffer + offset, 0); offset += 2; // properties len
// keys
m_Buffer[offset] = 1; offset++; // 1 key
htobe16buf (m_Buffer + offset, keyType); offset += 2; // key type
htobe16buf (m_Buffer + offset, keyLen); offset += 2; // key len
memcpy (m_Buffer + offset, encryptionPublicKey, keyLen); offset += keyLen; // key
// leases
uint32_t expirationTime = 0; // in seconds
m_Buffer[offset] = num; offset++; // num leases
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
auto ts = tunnels[i]->GetCreationTime () + i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT - i2p::tunnel::TUNNEL_EXPIRATION_THRESHOLD; // in seconds, 1 minute before expiration
if (ts > expirationTime) expirationTime = ts;
htobe32buf (m_Buffer + offset, ts);
offset += 4; // end date
}
// update expiration
SetExpirationTime (expirationTime*1000LL);
auto expires = expirationTime - timestamp;
htobe16buf (expiresBuf, expires > 0 ? expires : 0);
// sign
keys.Sign (m_Buffer, offset, m_Buffer + offset); // LS + leading store type
}
LocalLeaseSet2::LocalLeaseSet2 (uint8_t storeType, std::shared_ptr<const IdentityEx> identity, const uint8_t * buf, size_t len):
LocalLeaseSet (identity, nullptr, 0)
{
m_BufferLen = len;
m_Buffer = new uint8_t[m_BufferLen + 1];
memcpy (m_Buffer + 1, buf, len);
m_Buffer[0] = storeType;
}
LocalEncryptedLeaseSet2::LocalEncryptedLeaseSet2 (std::shared_ptr<const LocalLeaseSet2> ls, const i2p::data::PrivateKeys& keys, i2p::data::SigningKeyType blindedKeyType):
LocalLeaseSet2 (ls->GetIdentity ()), m_InnerLeaseSet (ls)
{
size_t lenInnerPlaintext = ls->GetBufferLen () + 1, lenOuterPlaintext = lenInnerPlaintext + 32 + 1,
lenOuterCiphertext = lenOuterPlaintext + 32;
m_BufferLen = 2/*blinded sig type*/ + 32/*blinded pub key*/ + 4/*published*/ + 2/*expires*/ + 2/*flags*/ + 2/*lenOuterCiphertext*/ + lenOuterCiphertext + 64/*signature*/;
m_Buffer = new uint8_t[m_BufferLen + 1];
m_Buffer[0] = NETDB_STORE_TYPE_ENCRYPTED_LEASESET2;
BlindedPublicKey blindedKey (ls->GetIdentity ());
auto timestamp = i2p::util::GetSecondsSinceEpoch ();
char date[9];
i2p::util::GetDateString (timestamp, date);
uint8_t blindedPriv[32], blindedPub[32];
blindedKey.BlindPrivateKey (keys.GetSigningPrivateKey (), date, blindedPriv, blindedPub);
std::unique_ptr<i2p::crypto::Signer> blindedSigner (i2p::data::PrivateKeys::CreateSigner (blindedKeyType, blindedPriv));
auto offset = 1;
htobe16buf (m_Buffer + offset, blindedKeyType); offset += 2; // Blinded Public Key Sig Type
memcpy (m_Buffer + offset, blindedPub, 32); offset += 32; // Blinded Public Key
htobe32buf (m_Buffer + offset, timestamp); offset += 4; // published timestamp (seconds)
auto nextMidnight = (timestamp/86400LL + 1)*86400LL; // 86400 = 24*3600 seconds
auto expirationTime = ls->GetExpirationTime ()/1000LL;
if (expirationTime > nextMidnight) expirationTime = nextMidnight;
SetExpirationTime (expirationTime*1000LL);
htobe16buf (m_Buffer + offset, expirationTime > timestamp ? expirationTime - timestamp : 0); offset += 2; // expires
uint16_t flags = 0;
htobe16buf (m_Buffer + offset, flags); offset += 2; // flags
htobe16buf (m_Buffer + offset, lenOuterCiphertext); offset += 2; // lenOuterCiphertext
// outerChipherText
// Layer 1
uint8_t subcredential[36];
blindedKey.GetSubcredential (blindedPub, 32, subcredential);
htobe32buf (subcredential + 32, timestamp); // outerInput = subcredential || publishedTimestamp
// keys = HKDF(outerSalt, outerInput, "ELS2_L1K", 44)
uint8_t keys1[64]; // 44 bytes actual data
RAND_bytes (m_Buffer + offset, 32); // outerSalt = CSRNG(32)
i2p::crypto::HKDF (m_Buffer + offset, subcredential, 36, "ELS2_L1K", keys1);
offset += 32; // outerSalt
uint8_t * outerPlainText = m_Buffer + offset;
m_Buffer[offset] = 0; offset++; // flag
// Layer 2
// keys = HKDF(outerSalt, outerInput, "ELS2_L2K", 44)
uint8_t keys2[64]; // 44 bytes actual data
RAND_bytes (m_Buffer + offset, 32); // innerSalt = CSRNG(32)
i2p::crypto::HKDF (m_Buffer + offset, subcredential, 36, "ELS2_L2K", keys2);
offset += 32; // innerSalt
m_Buffer[offset] = ls->GetStoreType ();
memcpy (m_Buffer + offset + 1, ls->GetBuffer (), ls->GetBufferLen ());
i2p::crypto::ChaCha20 (m_Buffer + offset, lenInnerPlaintext, keys2, keys2 + 32, m_Buffer + offset); // encrypt Layer 2
offset += lenInnerPlaintext;
i2p::crypto::ChaCha20 (outerPlainText, lenOuterPlaintext, keys1, keys1 + 32, outerPlainText); // encrypt Layer 1
// signature
blindedSigner->Sign (m_Buffer, offset, m_Buffer + offset);
// store hash
m_StoreHash = blindedKey.GetStoreHash (date);
}
LocalEncryptedLeaseSet2::LocalEncryptedLeaseSet2 (std::shared_ptr<const IdentityEx> identity, const uint8_t * buf, size_t len):
LocalLeaseSet2 (NETDB_STORE_TYPE_ENCRYPTED_LEASESET2, identity, buf, len)
{
// fill inner LeaseSet2
auto blindedKey = std::make_shared<BlindedPublicKey>(identity);
i2p::data::LeaseSet2 ls (buf, len, blindedKey); // inner layer
if (ls.IsValid ())
{
m_InnerLeaseSet = std::make_shared<LocalLeaseSet2>(ls.GetStoreType (), identity, ls.GetBuffer (), ls.GetBufferLen ());
m_StoreHash = blindedKey->GetStoreHash ();
}
else
LogPrint (eLogError, "LeaseSet2: couldn't extract inner layer");
}
}
}