mirror of
https://github.com/oxen-io/lokinet.git
synced 2024-10-29 11:05:43 +00:00
455 lines
13 KiB
C++
455 lines
13 KiB
C++
#include <service/protocol.hpp>
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#include <path/path.hpp>
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#include <routing/handler.hpp>
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#include <util/buffer.hpp>
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#include <util/logic.hpp>
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#include <util/mem.hpp>
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#include <util/meta/memfn.hpp>
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#include <utility>
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namespace llarp
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{
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namespace service
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{
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ProtocolMessage::ProtocolMessage()
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{
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tag.Zero();
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}
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ProtocolMessage::ProtocolMessage(const ConvoTag& t) : tag(t)
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{
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}
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ProtocolMessage::~ProtocolMessage() = default;
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void
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ProtocolMessage::PutBuffer(const llarp_buffer_t& buf)
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{
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payload.resize(buf.sz);
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memcpy(payload.data(), buf.base, buf.sz);
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}
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void
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ProtocolMessage::ProcessAsync(path::Path_ptr path, PathID_t from,
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std::shared_ptr< ProtocolMessage > self)
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{
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if(!self->handler->HandleDataMessage(path, from, self))
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LogWarn("failed to handle data message from ", path->Name());
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}
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bool
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ProtocolMessage::DecodeKey(const llarp_buffer_t& k, llarp_buffer_t* buf)
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{
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bool read = false;
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if(!BEncodeMaybeReadDictInt("a", proto, read, k, buf))
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return false;
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if(k == "d")
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{
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llarp_buffer_t strbuf;
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if(!bencode_read_string(buf, &strbuf))
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return false;
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PutBuffer(strbuf);
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return true;
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}
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if(!BEncodeMaybeReadDictEntry("i", introReply, read, k, buf))
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return false;
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if(!BEncodeMaybeReadDictInt("n", seqno, read, k, buf))
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return false;
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if(!BEncodeMaybeReadDictEntry("s", sender, read, k, buf))
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return false;
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if(!BEncodeMaybeReadDictEntry("t", tag, read, k, buf))
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return false;
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if(!BEncodeMaybeReadDictInt("v", version, read, k, buf))
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return false;
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return read;
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}
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bool
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ProtocolMessage::BEncode(llarp_buffer_t* buf) const
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{
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if(!bencode_start_dict(buf))
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return false;
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if(!BEncodeWriteDictInt("a", proto, buf))
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return false;
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if(!bencode_write_bytestring(buf, "d", 1))
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return false;
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if(!bencode_write_bytestring(buf, payload.data(), payload.size()))
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return false;
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if(!BEncodeWriteDictEntry("i", introReply, buf))
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return false;
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if(!BEncodeWriteDictInt("n", seqno, buf))
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return false;
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if(!BEncodeWriteDictEntry("s", sender, buf))
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return false;
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if(!tag.IsZero())
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{
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if(!BEncodeWriteDictEntry("t", tag, buf))
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return false;
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}
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if(!BEncodeWriteDictInt("v", version, buf))
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return false;
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return bencode_end(buf);
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}
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ProtocolFrame::~ProtocolFrame() = default;
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bool
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ProtocolFrame::BEncode(llarp_buffer_t* buf) const
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{
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if(!bencode_start_dict(buf))
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return false;
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if(!BEncodeWriteDictMsgType(buf, "A", "H"))
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return false;
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if(!C.IsZero())
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{
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if(!BEncodeWriteDictEntry("C", C, buf))
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return false;
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}
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if(D.size() > 0)
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{
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if(!BEncodeWriteDictEntry("D", D, buf))
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return false;
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}
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if(!BEncodeWriteDictEntry("F", F, buf))
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return false;
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if(!N.IsZero())
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{
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if(!BEncodeWriteDictEntry("N", N, buf))
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return false;
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}
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if(R)
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{
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if(!BEncodeWriteDictInt("R", R, buf))
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return false;
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}
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if(!T.IsZero())
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{
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if(!BEncodeWriteDictEntry("T", T, buf))
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return false;
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}
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if(!BEncodeWriteDictInt("V", version, buf))
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return false;
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if(!BEncodeWriteDictEntry("Z", Z, buf))
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return false;
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return bencode_end(buf);
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}
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bool
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ProtocolFrame::DecodeKey(const llarp_buffer_t& key, llarp_buffer_t* val)
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{
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bool read = false;
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if(key == "A")
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{
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llarp_buffer_t strbuf;
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if(!bencode_read_string(val, &strbuf))
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return false;
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if(strbuf.sz != 1)
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return false;
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return *strbuf.cur == 'H';
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}
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if(!BEncodeMaybeReadDictEntry("D", D, read, key, val))
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return false;
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if(!BEncodeMaybeReadDictEntry("F", F, read, key, val))
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return false;
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if(!BEncodeMaybeReadDictEntry("C", C, read, key, val))
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return false;
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if(!BEncodeMaybeReadDictEntry("N", N, read, key, val))
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return false;
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if(!BEncodeMaybeReadDictInt("S", S, read, key, val))
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return false;
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if(!BEncodeMaybeReadDictInt("R", R, read, key, val))
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return false;
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if(!BEncodeMaybeReadDictEntry("T", T, read, key, val))
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return false;
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if(!BEncodeMaybeReadVersion("V", version, LLARP_PROTO_VERSION, read, key,
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val))
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return false;
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if(!BEncodeMaybeReadDictEntry("Z", Z, read, key, val))
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return false;
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return read;
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}
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bool
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ProtocolFrame::DecryptPayloadInto(const SharedSecret& sharedkey,
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ProtocolMessage& msg) const
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{
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Encrypted_t tmp = D;
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auto buf = tmp.Buffer();
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CryptoManager::instance()->xchacha20(*buf, sharedkey, N);
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return bencode_decode_dict(msg, buf);
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}
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bool
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ProtocolFrame::Sign(const Identity& localIdent)
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{
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Z.Zero();
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std::array< byte_t, MAX_PROTOCOL_MESSAGE_SIZE > tmp;
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llarp_buffer_t buf(tmp);
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// encode
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if(!BEncode(&buf))
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{
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LogError("message too big to encode");
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return false;
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}
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// rewind
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buf.sz = buf.cur - buf.base;
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buf.cur = buf.base;
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// sign
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return localIdent.Sign(Z, buf);
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}
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bool
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ProtocolFrame::EncryptAndSign(const ProtocolMessage& msg,
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const SharedSecret& sessionKey,
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const Identity& localIdent)
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{
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std::array< byte_t, MAX_PROTOCOL_MESSAGE_SIZE > tmp;
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llarp_buffer_t buf(tmp);
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// encode message
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if(!msg.BEncode(&buf))
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{
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LogError("message too big to encode");
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return false;
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}
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// rewind
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buf.sz = buf.cur - buf.base;
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buf.cur = buf.base;
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// encrypt
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CryptoManager::instance()->xchacha20(buf, sessionKey, N);
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// put encrypted buffer
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D = buf;
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// zero out signature
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Z.Zero();
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llarp_buffer_t buf2(tmp);
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// encode frame
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if(!BEncode(&buf2))
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{
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LogError("frame too big to encode");
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DumpBuffer(buf2);
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return false;
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}
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// rewind
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buf2.sz = buf2.cur - buf2.base;
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buf2.cur = buf2.base;
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// sign
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if(!localIdent.Sign(Z, buf2))
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{
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LogError("failed to sign? wtf?!");
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return false;
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}
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return true;
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}
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struct AsyncFrameDecrypt
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{
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path::Path_ptr path;
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std::shared_ptr< Logic > logic;
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std::shared_ptr< ProtocolMessage > msg;
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const Identity& m_LocalIdentity;
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IDataHandler* handler;
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const ProtocolFrame frame;
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const Introduction fromIntro;
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AsyncFrameDecrypt(std::shared_ptr< Logic > l, const Identity& localIdent,
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IDataHandler* h, std::shared_ptr< ProtocolMessage > m,
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const ProtocolFrame& f, const Introduction& recvIntro)
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: logic(std::move(l))
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, msg(std::move(m))
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, m_LocalIdentity(localIdent)
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, handler(h)
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, frame(f)
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, fromIntro(recvIntro)
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{
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}
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static void
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Work(void* user)
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{
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auto* self = static_cast< AsyncFrameDecrypt* >(user);
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auto crypto = CryptoManager::instance();
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SharedSecret K;
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SharedSecret sharedKey;
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// copy
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ProtocolFrame frame(self->frame);
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if(!crypto->pqe_decrypt(self->frame.C, K,
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pq_keypair_to_secret(self->m_LocalIdentity.pq)))
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{
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LogError("pqke failed C=", self->frame.C);
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self->msg.reset();
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delete self;
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return;
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}
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// decrypt
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auto buf = frame.D.Buffer();
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crypto->xchacha20(*buf, K, self->frame.N);
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if(!bencode_decode_dict(*self->msg, buf))
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{
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LogError("failed to decode inner protocol message");
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DumpBuffer(*buf);
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self->msg.reset();
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delete self;
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return;
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}
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// verify signature of outer message after we parsed the inner message
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if(!self->frame.Verify(self->msg->sender))
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{
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LogError("intro frame has invalid signature Z=", self->frame.Z,
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" from ", self->msg->sender.Addr());
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Dump< MAX_PROTOCOL_MESSAGE_SIZE >(self->frame);
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Dump< MAX_PROTOCOL_MESSAGE_SIZE >(*self->msg);
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self->msg.reset();
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delete self;
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return;
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}
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if(self->handler->HasConvoTag(self->msg->tag))
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{
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LogError("dropping duplicate convo tag T=", self->msg->tag);
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// TODO: send convotag reset
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self->msg.reset();
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delete self;
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return;
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}
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// PKE (A, B, N)
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SharedSecret sharedSecret;
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path_dh_func dh_server =
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util::memFn(&Crypto::dh_server, CryptoManager::instance());
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if(!self->m_LocalIdentity.KeyExchange(dh_server, sharedSecret,
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self->msg->sender, self->frame.N))
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{
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LogError("x25519 key exchange failed");
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Dump< MAX_PROTOCOL_MESSAGE_SIZE >(self->frame);
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self->msg.reset();
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delete self;
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return;
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}
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std::array< byte_t, 64 > tmp;
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// K
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std::copy(K.begin(), K.end(), tmp.begin());
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// S = HS( K + PKE( A, B, N))
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std::copy(sharedSecret.begin(), sharedSecret.end(), tmp.begin() + 32);
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crypto->shorthash(sharedKey, llarp_buffer_t(tmp));
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self->handler->PutIntroFor(self->msg->tag, self->msg->introReply);
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self->handler->PutReplyIntroFor(self->msg->tag, self->fromIntro);
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self->handler->PutSenderFor(self->msg->tag, self->msg->sender, true);
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self->handler->PutCachedSessionKeyFor(self->msg->tag, sharedKey);
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self->msg->handler = self->handler;
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std::shared_ptr< ProtocolMessage > msg = std::move(self->msg);
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path::Path_ptr path = std::move(self->path);
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const PathID_t from = self->frame.F;
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self->logic->queue_func(
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[=]() { ProtocolMessage::ProcessAsync(path, from, msg); });
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delete self;
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}
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};
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ProtocolFrame&
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ProtocolFrame::operator=(const ProtocolFrame& other)
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{
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C = other.C;
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D = other.D;
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F = other.F;
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N = other.N;
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Z = other.Z;
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T = other.T;
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R = other.R;
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S = other.S;
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version = other.version;
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return *this;
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}
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bool
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ProtocolFrame::AsyncDecryptAndVerify(
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std::shared_ptr< Logic > logic, path::Path_ptr recvPath,
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const std::shared_ptr< llarp::thread::ThreadPool >& worker,
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const Identity& localIdent, IDataHandler* handler) const
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{
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auto msg = std::make_shared< ProtocolMessage >();
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if(T.IsZero())
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{
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LogInfo("Got protocol frame with new convo");
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// we need to dh
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auto dh = new AsyncFrameDecrypt(logic, localIdent, handler, msg, *this,
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recvPath->intro);
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dh->path = recvPath;
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return worker->addJob(std::bind(&AsyncFrameDecrypt::Work, dh));
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}
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SharedSecret shared;
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if(!handler->GetCachedSessionKeyFor(T, shared))
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{
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LogError("No cached session for T=", T);
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return false;
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}
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ServiceInfo si;
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if(!handler->GetSenderFor(T, si))
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{
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LogError("No sender for T=", T);
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return false;
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}
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if(!Verify(si))
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{
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LogError("Signature failure from ", si.Addr());
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return false;
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}
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if(!DecryptPayloadInto(shared, *msg))
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{
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LogError("failed to decrypt message");
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return false;
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}
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if(T != msg->tag && !msg->tag.IsZero())
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{
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LogError("convotag missmatch: ", T, " != ", msg->tag);
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return false;
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}
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msg->handler = handler;
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const PathID_t fromPath = F;
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logic->queue_func(
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[=]() { ProtocolMessage::ProcessAsync(recvPath, fromPath, msg); });
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return true;
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}
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bool
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ProtocolFrame::operator==(const ProtocolFrame& other) const
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{
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return C == other.C && D == other.D && N == other.N && Z == other.Z
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&& T == other.T && S == other.S && version == other.version;
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}
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bool
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ProtocolFrame::Verify(const ServiceInfo& svc) const
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{
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ProtocolFrame copy(*this);
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// save signature
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// zero out signature for verify
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copy.Z.Zero();
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// serialize
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std::array< byte_t, MAX_PROTOCOL_MESSAGE_SIZE > tmp;
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llarp_buffer_t buf(tmp);
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if(!copy.BEncode(&buf))
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{
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LogError("bencode fail");
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return false;
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}
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// rewind buffer
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buf.sz = buf.cur - buf.base;
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buf.cur = buf.base;
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// verify
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return svc.Verify(buf, Z);
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}
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bool
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ProtocolFrame::HandleMessage(routing::IMessageHandler* h,
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ABSL_ATTRIBUTE_UNUSED AbstractRouter* r) const
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{
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return h->HandleHiddenServiceFrame(*this);
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}
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} // namespace service
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} // namespace llarp
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