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Code Issues Releases Activity

KDF for session request

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This commit is contained in:
orignal 2022-03-04 21:51:40 -05:00
parent f6ba776c12
commit 35542d803c
2 changed files with 58 additions and 42 deletions
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70
libi2pd/SSU2.cpp
View File

@ -17,6 +17,13 @@ namespace i2p
{
namespace transport
{
static uint64_t CreateHeaderMask (const uint8_t * kh, const uint8_t * nonce)
{
uint64_t data = 0;
i2p::crypto::ChaCha20 ((uint8_t *)&data, 8, kh, nonce, (uint8_t *)&data);
return data;
}
SSU2Session::SSU2Session (SSU2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter,
std::shared_ptr<const i2p::data::RouterInfo::Address> addr, bool peerTest):
TransportSession (in_RemoteRouter, SSU2_TERMINATION_TIMEOUT),
@ -37,49 +44,54 @@ namespace transport
void SSU2Session::SendSessionRequest ()
{
m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair ();
m_NoiseState->MixHash (m_EphemeralKeys->GetPublicKey (), 32);
uint8_t sharedSecret[32];
m_EphemeralKeys->Agree (m_Address->s, sharedSecret);
m_NoiseState->MixKey (sharedSecret);
m_NoiseState->MixHash (m_Address->s, 32); // h = SHA256(h || bpk)
Header header;
uint8_t headerX[48], payload[1200]; // TODO: correct payload size
size_t payloadSize = 8;
// fill packet
RAND_bytes ((uint8_t *)&m_DestConnID, 8);
header.h.connID = m_DestConnID; // dest id
memset (header.h.packetNum, 0, 4);
header.h.type = eSSU2SessionRequest;
header.h.flags[0] = 2; // ver
header.h.flags[1] = 2; // netID TODO:
header.h.flags[2] = 0; // flag
memset (header.h.h2.h.packetNum, 0, 4);
header.h.h2.h.type = eSSU2SessionRequest;
header.h.h2.h.flags[0] = 2; // ver
header.h.h2.h.flags[1] = 2; // netID TODO:
header.h.h2.h.flags[2] = 0; // flag
RAND_bytes ((uint8_t *)&m_SourceConnID, 8);
memcpy (headerX, &m_SourceConnID, 8); // source id
memset (headerX + 8, 0, 8); // token
memcpy (headerX + 16, m_EphemeralKeys->GetPublicKey (), 32); // X
m_Server.AddPendingOutgoingSession (boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port), shared_from_this ());
// KDF for session request
m_NoiseState->MixHash (header.buf, 16); // h = SHA256(h || header) TODO: long header
m_NoiseState->MixHash (m_EphemeralKeys->GetPublicKey (), 32); // h = SHA256(h || aepk);
uint8_t sharedSecret[32];
m_EphemeralKeys->Agree (m_Address->s, sharedSecret);
m_NoiseState->MixKey (sharedSecret);
// encrypt
header.ll[0] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 24));
header.ll[1] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 12));
const uint8_t nonce[12] = {0};
i2p::crypto::ChaCha20 (headerX, 48, m_Address->i, nonce, headerX);
i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, payloadSize + 16, true);
payloadSize += 16;
CreateHeaderMask (m_Address->i, payload + (payloadSize - 24), m_Address->i, payload + (payloadSize - 12));
EncryptHeader (header);
i2p::crypto::ChaCha20 (headerX, 48, m_Address->i, nonce, headerX);
// send
m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port));
}
void SSU2Session::EncryptHeader (Header& h)
bool SSU2Session::ProcessSessionCreated (uint8_t * buf, size_t len)
{
h.ll[0] ^= m_HeaderMask.ll[0];
h.ll[1] ^= m_HeaderMask.ll[1];
}
void SSU2Session::CreateHeaderMask (const uint8_t * kh1, const uint8_t * nonce1, const uint8_t * kh2, const uint8_t * nonce2)
{
// Header Encryption KDF
uint8_t data[8] = {0};
i2p::crypto::ChaCha20 (data, 8, kh1, nonce1, m_HeaderMask.buf);
i2p::crypto::ChaCha20 (data, 8, kh2, nonce2, m_HeaderMask.buf + 8);
Header2 h2;
memcpy (h2.buf, buf, 8);
uint8_t kh2[32];
i2p::crypto::HKDF (m_NoiseState->m_CK, nullptr, 0, "SessCreateHeader", kh2, 32); // k_header_2 = HKDF(chainKey, ZEROLEN, "SessCreateHeader", 32)
h2.ll ^= CreateHeaderMask (kh2, buf + (len - 12));
if (h2.h.type != eSSU2SessionCreated)
{
LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)h2.h.type);
return false;
}
return true;
}
SSU2Server::SSU2Server (int port):
@ -116,10 +128,9 @@ namespace transport
void SSU2Server::ProcessNextPacket (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
{
uint64_t key = 0, connID;
i2p::crypto::ChaCha20 ((uint8_t *)&key, 8, i2p::context.GetSSU2IntroKey (), buf + (len - 24), (uint8_t *)&key); // TODO: use SSU2 intro key
uint64_t connID;
memcpy (&connID, buf, 8);
connID ^= key;
connID ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 24));
auto it = m_Sessions.find (connID);
if (it != m_Sessions.end ())
{
@ -130,7 +141,8 @@ namespace transport
auto it1 = m_PendingOutgoingSessions.find (senderEndpoint);
if (it1 != m_PendingOutgoingSessions.end ())
{
m_PendingOutgoingSessions.erase (it1);
if (it1->second->ProcessSessionCreated (buf, len))
m_PendingOutgoingSessions.erase (it1);
}
else
{

30
libi2pd/SSU2.h
View File

@ -27,12 +27,24 @@ namespace transport
enum SSU2MessageType
{
eSSU2SessionRequest = 0
eSSU2SessionRequest = 0,
eSSU2SessionCreated = 1
};
class SSU2Server;
class SSU2Session: public TransportSession, public std::enable_shared_from_this<SSU2Session>
{
union Header2
{
uint64_t ll;
uint8_t buf[8];
struct
{
uint8_t packetNum[4];
uint8_t type;
uint8_t flags[3];
} h;
};
union Header
{
uint64_t ll[2];
@ -40,9 +52,7 @@ namespace transport
struct
{
uint64_t connID;
uint8_t packetNum[4];
uint8_t type;
uint8_t flags[3];
Header2 h2;
} h;
};
@ -52,12 +62,12 @@ namespace transport
std::shared_ptr<const i2p::data::RouterInfo::Address> addr = nullptr, bool peerTest = false);
~SSU2Session ();
bool ProcessSessionCreated (uint8_t * buf, size_t len);
private:
void SendSessionRequest ();
void EncryptHeader (Header& h);
void CreateHeaderMask (const uint8_t * kh1, const uint8_t * nonce1, const uint8_t * kh2, const uint8_t * nonce2);
private:
SSU2Server& m_Server;
@ -65,12 +75,6 @@ namespace transport
std::unique_ptr<i2p::crypto::NoiseSymmetricState> m_NoiseState;
std::shared_ptr<const i2p::data::RouterInfo::Address> m_Address;
uint64_t m_DestConnID, m_SourceConnID;
union
{
uint64_t ll[2];
uint8_t buf[16];
} m_HeaderMask;
};
class SSU2Server