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create encrypted LeaseSet2 with authentication

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orignal 2019-07-12 15:37:32 -04:00
parent a090114066
commit 7d68ccca53
2 changed files with 79 additions and 7 deletions
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69
libi2pd/LeaseSet.cpp
View file

@ -809,12 +809,20 @@ namespace data
m_Buffer[0] = storeType;
}
LocalEncryptedLeaseSet2::LocalEncryptedLeaseSet2 (std::shared_ptr<const LocalLeaseSet2> ls, const i2p::data::PrivateKeys& keys, i2p::data::SigningKeyType blindedKeyType):
LocalEncryptedLeaseSet2::LocalEncryptedLeaseSet2 (std::shared_ptr<const LocalLeaseSet2> ls, const i2p::data::PrivateKeys& keys,
LeaseSetAuthType authType, std::shared_ptr<std::vector<AuthPublicKey> > authKeys):
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*/;
uint8_t layer1Flags = 0;
if (authKeys)
{
if (authType == eLeaseSetAuthTypeDH) layer1Flags |= 0x01; // DH, authentication scheme 0, auth bit 1
else if (authType == eLeaseSetAuthTypePSK) layer1Flags |= 0x03; // PSK, authentication scheme 1, auth bit 1
m_BufferLen += authKeys->size ()*40 + 2; // auth data len
}
m_Buffer = new uint8_t[m_BufferLen + 1];
m_Buffer[0] = NETDB_STORE_TYPE_ENCRYPTED_LEASESET2;
BlindedPublicKey blindedKey (ls->GetIdentity ());
@ -823,9 +831,9 @@ namespace data
i2p::util::GetDateString (timestamp, date);
uint8_t blindedPriv[64], blindedPub[128]; // 64 and 128 max
size_t publicKeyLen = blindedKey.BlindPrivateKey (keys.GetSigningPrivateKey (), date, blindedPriv, blindedPub);
std::unique_ptr<i2p::crypto::Signer> blindedSigner (i2p::data::PrivateKeys::CreateSigner (blindedKeyType, blindedPriv));
std::unique_ptr<i2p::crypto::Signer> blindedSigner (i2p::data::PrivateKeys::CreateSigner (blindedKey.GetBlindedSigType (), blindedPriv));
auto offset = 1;
htobe16buf (m_Buffer + offset, blindedKeyType); offset += 2; // Blinded Public Key Sig Type
htobe16buf (m_Buffer + offset, blindedKey.GetBlindedSigType ()); offset += 2; // Blinded Public Key Sig Type
memcpy (m_Buffer + offset, blindedPub, publicKeyLen); offset += publicKeyLen; // Blinded Public Key
htobe32buf (m_Buffer + offset, timestamp); offset += 4; // published timestamp (seconds)
auto nextMidnight = (timestamp/86400LL + 1)*86400LL; // 86400 = 24*3600 seconds
@ -847,12 +855,27 @@ namespace data
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
m_Buffer[offset] = layer1Flags; offset++; // layer 1 flags
// auth data
uint8_t innerInput[68]; // authCookie || subcredential || publishedTimestamp
if (layer1Flags)
{
RAND_bytes (innerInput, 32); // authCookie
htobe16buf (m_Buffer + offset, authKeys->size ()); offset += 2; // num clients
CreateClientAuthData (subcredential, authType, authKeys, innerInput, m_Buffer);
offset += authKeys->size ()*40; // auth clients
}
// 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);
if (layer1Flags)
{
memcpy (innerInput + 32, subcredential, 36); // + subcredential || publishedTimestamp
i2p::crypto::HKDF (m_Buffer + offset, innerInput, 68, "ELS2_L2K", keys2);
}
else
i2p::crypto::HKDF (m_Buffer + offset, subcredential, 36, "ELS2_L2K", keys2); // no authCookie
offset += 32; // innerSalt
m_Buffer[offset] = ls->GetStoreType ();
memcpy (m_Buffer + offset + 1, ls->GetBuffer (), ls->GetBufferLen ());
@ -879,6 +902,40 @@ namespace data
else
LogPrint (eLogError, "LeaseSet2: couldn't extract inner layer");
}
void LocalEncryptedLeaseSet2::CreateClientAuthData (const uint8_t * subcredential, LeaseSetAuthType authType, std::shared_ptr<std::vector<AuthPublicKey> > authKeys, const uint8_t * authCookie, uint8_t * authClients) const
{
if (authType == eLeaseSetAuthTypeDH)
{
i2p::crypto::X25519Keys ek;
ek.GenerateKeys (); // esk and epk
uint8_t authInput[100]; // sharedSecret || cpk_i || subcredential || publishedTimestamp
memcpy (authInput + 64, subcredential, 36);
for (auto& it: *authKeys)
{
ek.Agree (it, authInput); // sharedSecret = DH(esk, cpk_i)
memcpy (authInput + 32, it, 32);
uint8_t okm[64]; // 52 actual data
i2p::crypto::HKDF (ek.GetPublicKey (), authInput, 100, "ELS2_XCA", okm);
memcpy (authClients, okm + 44, 8); authClients += 8; // clientID_i
i2p::crypto::ChaCha20 (authCookie, 32, okm, okm + 32, authClients); authClients += 32; // clientCookie_i
}
}
else // assume PSK
{
uint8_t authSalt[32];
RAND_bytes (authSalt, 32);
uint8_t authInput[68]; // authInput = psk_i || subcredential || publishedTimestamp
memcpy (authInput + 32, subcredential, 36);
for (auto& it: *authKeys)
{
memcpy (authInput, it, 32);
uint8_t okm[64]; // 52 actual data
i2p::crypto::HKDF (authSalt, authInput, 68, "ELS2PSKA", okm);
memcpy (authClients, okm + 44, 8); authClients += 8; // clientID_i
i2p::crypto::ChaCha20 (authCookie, 32, okm, okm + 32, authClients); authClients += 32; // clientCookie_i
}
}
}
}
}

17
libi2pd/LeaseSet.h
View file

@ -247,17 +247,32 @@ namespace data
size_t m_BufferLen;
};
class LocalEncryptedLeaseSet2: public LocalLeaseSet2
{
public:
LocalEncryptedLeaseSet2 (std::shared_ptr<const LocalLeaseSet2> ls, const i2p::data::PrivateKeys& keys, i2p::data::SigningKeyType blindedKeyType = i2p::data::SIGNING_KEY_TYPE_REDDSA_SHA512_ED25519);
enum LeaseSetAuthType
{
eLeaseSetAuthTypeNone = 0,
eLeaseSetAuthTypeDH = 1,
eLeaseSetAuthTypePSK = 2
};
typedef i2p::data::Tag<32> AuthPublicKey;
public:
LocalEncryptedLeaseSet2 (std::shared_ptr<const LocalLeaseSet2> ls, const i2p::data::PrivateKeys& keys, LeaseSetAuthType authType = eLeaseSetAuthTypeNone, std::shared_ptr<std::vector<AuthPublicKey> > authKeys = nullptr);
LocalEncryptedLeaseSet2 (std::shared_ptr<const IdentityEx> identity, const uint8_t * buf, size_t len); // from I2CP
const IdentHash& GetStoreHash () const { return m_StoreHash; };
std::shared_ptr<const LocalLeaseSet> GetInnerLeaseSet () const { return m_InnerLeaseSet; };
private:
void CreateClientAuthData (const uint8_t * subcredential, LeaseSetAuthType authType, std::shared_ptr<std::vector<AuthPublicKey> > authKeys, const uint8_t * authCookie, uint8_t * authClients) const;
private:
IdentHash m_StoreHash;