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lokinet/llarp/service/protocol.cpp
Jeff Becker 280d85d478
handle protocol discard
2019-03-08 11:00:45 -05:00

440 lines
12 KiB
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#include <service/protocol.hpp>
#include <routing/handler.hpp>
#include <util/buffer.hpp>
#include <util/logic.hpp>
#include <util/mem.hpp>
namespace llarp
{
namespace service
{
ProtocolMessage::ProtocolMessage()
{
tag.Zero();
}
ProtocolMessage::ProtocolMessage(const ConvoTag& t) : tag(t)
{
}
ProtocolMessage::~ProtocolMessage()
{
}
void
ProtocolMessage::PutBuffer(const llarp_buffer_t& buf)
{
payload.resize(buf.sz);
memcpy(payload.data(), buf.base, buf.sz);
}
void
ProtocolMessage::ProcessAsync(void* user)
{
ProtocolMessage* self = static_cast< ProtocolMessage* >(user);
if(!self->handler->HandleDataMessage(self->srcPath, self))
llarp::LogWarn("failed to handle data message from ", self->srcPath);
delete self;
}
bool
ProtocolMessage::DecodeKey(const llarp_buffer_t& k, llarp_buffer_t* buf)
{
bool read = false;
if(!BEncodeMaybeReadDictInt("a", proto, read, k, buf))
return false;
if(k == "d")
{
llarp_buffer_t strbuf;
if(!bencode_read_string(buf, &strbuf))
return false;
PutBuffer(strbuf);
return true;
}
if(!BEncodeMaybeReadDictEntry("i", introReply, read, k, buf))
return false;
if(!BEncodeMaybeReadDictEntry("s", sender, read, k, buf))
return false;
if(!BEncodeMaybeReadDictEntry("t", tag, read, k, buf))
return false;
if(!BEncodeMaybeReadDictInt("v", version, read, k, buf))
return false;
return read;
}
bool
ProtocolMessage::BEncode(llarp_buffer_t* buf) const
{
if(!bencode_start_dict(buf))
return false;
if(!BEncodeWriteDictInt("a", proto, buf))
return false;
if(!bencode_write_bytestring(buf, "d", 1))
return false;
if(!bencode_write_bytestring(buf, payload.data(), payload.size()))
return false;
if(!BEncodeWriteDictEntry("i", introReply, buf))
return false;
if(!BEncodeWriteDictEntry("s", sender, buf))
return false;
if(!tag.IsZero())
{
if(!BEncodeWriteDictEntry("t", tag, buf))
return false;
}
if(!BEncodeWriteDictInt("v", version, buf))
return false;
return bencode_end(buf);
}
ProtocolFrame::~ProtocolFrame()
{
}
bool
ProtocolFrame::BEncode(llarp_buffer_t* buf) const
{
if(!bencode_start_dict(buf))
return false;
if(!BEncodeWriteDictMsgType(buf, "A", "H"))
return false;
if(!C.IsZero())
{
if(!BEncodeWriteDictEntry("C", C, buf))
return false;
}
if(D.size() > 0)
{
if(!BEncodeWriteDictEntry("D", D, buf))
return false;
}
if(!BEncodeWriteDictEntry("F", F, buf))
return false;
if(!N.IsZero())
{
if(!BEncodeWriteDictEntry("N", N, buf))
return false;
}
if(R)
{
if(!BEncodeWriteDictInt("R", R, buf))
return false;
}
if(!T.IsZero())
{
if(!BEncodeWriteDictEntry("T", T, buf))
return false;
}
if(!BEncodeWriteDictInt("V", version, buf))
return false;
if(!BEncodeWriteDictEntry("Z", Z, buf))
return false;
return bencode_end(buf);
}
bool
ProtocolFrame::DecodeKey(const llarp_buffer_t& key, llarp_buffer_t* val)
{
bool read = false;
if(key == "A")
{
llarp_buffer_t strbuf;
if(!bencode_read_string(val, &strbuf))
return false;
if(strbuf.sz != 1)
return false;
return *strbuf.cur == 'H';
}
if(!BEncodeMaybeReadDictEntry("D", D, read, key, val))
return false;
if(!BEncodeMaybeReadDictEntry("F", F, read, key, val))
return false;
if(!BEncodeMaybeReadDictEntry("C", C, read, key, val))
return false;
if(!BEncodeMaybeReadDictEntry("N", N, read, key, val))
return false;
if(!BEncodeMaybeReadDictInt("S", S, read, key, val))
return false;
if(!BEncodeMaybeReadDictInt("R", R, read, key, val))
return false;
if(!BEncodeMaybeReadDictEntry("T", T, read, key, val))
return false;
if(!BEncodeMaybeReadVersion("V", version, LLARP_PROTO_VERSION, read, key,
val))
return false;
if(!BEncodeMaybeReadDictEntry("Z", Z, read, key, val))
return false;
return read;
}
bool
ProtocolFrame::DecryptPayloadInto(llarp::Crypto* crypto,
const SharedSecret& sharedkey,
ProtocolMessage& msg) const
{
Encrypted_t tmp = D;
auto buf = tmp.Buffer();
crypto->xchacha20(*buf, sharedkey, N);
return msg.BDecode(buf);
}
bool
ProtocolFrame::Sign(llarp::Crypto* crypto, const Identity& localIdent)
{
Z.Zero();
std::array< byte_t, MAX_PROTOCOL_MESSAGE_SIZE > tmp;
llarp_buffer_t buf(tmp);
// encode
if(!BEncode(&buf))
{
llarp::LogError("message too big to encode");
return false;
}
// rewind
buf.sz = buf.cur - buf.base;
buf.cur = buf.base;
// sign
return localIdent.Sign(crypto, Z, buf);
}
bool
ProtocolFrame::EncryptAndSign(llarp::Crypto* crypto,
const ProtocolMessage& msg,
const SharedSecret& sessionKey,
const Identity& localIdent)
{
std::array< byte_t, MAX_PROTOCOL_MESSAGE_SIZE > tmp;
llarp_buffer_t buf(tmp);
// encode message
if(!msg.BEncode(&buf))
{
llarp::LogError("message too big to encode");
return false;
}
// rewind
buf.sz = buf.cur - buf.base;
buf.cur = buf.base;
// encrypt
crypto->xchacha20(buf, sessionKey, N);
// put encrypted buffer
D = buf;
// zero out signature
Z.Zero();
llarp_buffer_t buf2(tmp);
// encode frame
if(!BEncode(&buf2))
{
llarp::LogError("frame too big to encode");
llarp::DumpBuffer(buf2);
return false;
}
// rewind
buf2.sz = buf2.cur - buf2.base;
buf2.cur = buf2.base;
// sign
if(!localIdent.Sign(crypto, Z, buf2))
{
llarp::LogError("failed to sign? wtf?!");
return false;
}
return true;
}
struct AsyncFrameDecrypt
{
llarp::Crypto* crypto;
llarp::Logic* logic;
ProtocolMessage* msg;
const Identity& m_LocalIdentity;
IDataHandler* handler;
const ProtocolFrame frame;
AsyncFrameDecrypt(llarp::Logic* l, llarp::Crypto* c,
const Identity& localIdent, IDataHandler* h,
ProtocolMessage* m, const ProtocolFrame& f)
: crypto(c)
, logic(l)
, msg(m)
, m_LocalIdentity(localIdent)
, handler(h)
, frame(f)
{
}
static void
Work(void* user)
{
AsyncFrameDecrypt* self = static_cast< AsyncFrameDecrypt* >(user);
auto crypto = self->crypto;
SharedSecret K;
SharedSecret sharedKey;
// copy
ProtocolFrame frame(self->frame);
if(!crypto->pqe_decrypt(self->frame.C, K,
pq_keypair_to_secret(self->m_LocalIdentity.pq)))
{
llarp::LogError("pqke failed C=", self->frame.C);
delete self->msg;
delete self;
return;
}
// decrypt
auto buf = frame.D.Buffer();
crypto->xchacha20(*buf, K, self->frame.N);
if(!self->msg->BDecode(buf))
{
llarp::LogError("failed to decode inner protocol message");
llarp::DumpBuffer(*buf);
delete self->msg;
delete self;
return;
}
// verify signature of outer message after we parsed the inner message
if(!self->frame.Verify(crypto, self->msg->sender))
{
llarp::LogError("intro frame has invalid signature Z=", self->frame.Z,
" from ", self->msg->sender.Addr());
self->frame.Dump< MAX_PROTOCOL_MESSAGE_SIZE >();
self->msg->Dump< MAX_PROTOCOL_MESSAGE_SIZE >();
delete self->msg;
delete self;
return;
}
// PKE (A, B, N)
SharedSecret sharedSecret;
using namespace std::placeholders;
path_dh_func dh_server =
std::bind(&Crypto::dh_server, self->crypto, _1, _2, _3, _4);
if(!self->m_LocalIdentity.KeyExchange(dh_server, sharedSecret,
self->msg->sender, self->frame.N))
{
llarp::LogError("x25519 key exchange failed");
self->frame.Dump< MAX_PROTOCOL_MESSAGE_SIZE >();
delete self->msg;
delete self;
return;
}
std::array< byte_t, 64 > tmp;
// K
std::copy(K.begin(), K.end(), tmp.begin());
// S = HS( K + PKE( A, B, N))
std::copy(sharedSecret.begin(), sharedSecret.end(), tmp.begin() + 32);
crypto->shorthash(sharedKey, llarp_buffer_t(tmp));
self->handler->PutIntroFor(self->msg->tag, self->msg->introReply);
self->handler->PutSenderFor(self->msg->tag, self->msg->sender);
self->handler->PutCachedSessionKeyFor(self->msg->tag, sharedKey);
self->msg->handler = self->handler;
self->logic->queue_job({self->msg, &ProtocolMessage::ProcessAsync});
delete self;
}
};
ProtocolFrame&
ProtocolFrame::operator=(const ProtocolFrame& other)
{
C = other.C;
D = other.D;
F = other.F;
N = other.N;
Z = other.Z;
T = other.T;
R = other.R;
S = other.S;
version = other.version;
return *this;
}
bool
ProtocolFrame::AsyncDecryptAndVerify(llarp::Logic* logic, llarp::Crypto* c,
const PathID_t& srcPath,
llarp_threadpool* worker,
const Identity& localIdent,
IDataHandler* handler) const
{
if(T.IsZero())
{
llarp::LogInfo("Got protocol frame with new convo");
ProtocolMessage* msg = new ProtocolMessage();
msg->srcPath = srcPath;
// we need to dh
auto dh =
new AsyncFrameDecrypt(logic, c, localIdent, handler, msg, *this);
llarp_threadpool_queue_job(worker, {dh, &AsyncFrameDecrypt::Work});
return true;
}
SharedSecret shared;
if(!handler->GetCachedSessionKeyFor(T, shared))
{
llarp::LogError("No cached session for T=", T);
return false;
}
ServiceInfo si;
if(!handler->GetSenderFor(T, si))
{
llarp::LogError("No sender for T=", T);
return false;
}
if(!Verify(c, si))
{
llarp::LogError("Signature failure from ", si.Addr());
return false;
}
ProtocolMessage* msg = new ProtocolMessage();
if(!DecryptPayloadInto(c, shared, *msg))
{
llarp::LogError("failed to decrypt message");
delete msg;
return false;
}
msg->srcPath = srcPath;
msg->handler = handler;
logic->queue_job({msg, &ProtocolMessage::ProcessAsync});
return true;
}
bool
ProtocolFrame::operator==(const ProtocolFrame& other) const
{
return C == other.C && D == other.D && N == other.N && Z == other.Z
&& T == other.T && S == other.S && version == other.version;
}
bool
ProtocolFrame::Verify(llarp::Crypto* crypto, const ServiceInfo& from) const
{
ProtocolFrame copy(*this);
// save signature
// zero out signature for verify
copy.Z.Zero();
// serialize
std::array< byte_t, MAX_PROTOCOL_MESSAGE_SIZE > tmp;
llarp_buffer_t buf(tmp);
if(!copy.BEncode(&buf))
{
llarp::LogError("bencode fail");
return false;
}
// rewind buffer
buf.sz = buf.cur - buf.base;
buf.cur = buf.base;
// verify
return from.Verify(crypto, buf, Z);
}
bool
ProtocolFrame::HandleMessage(llarp::routing::IMessageHandler* h,
__attribute__((unused))
AbstractRouter* r) const
{
return h->HandleHiddenServiceFrame(this);
}
} // namespace service
} // namespace llarp
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