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#include "channel.h"
#include <algorithm>
#include <stdexcept>
#include <openssl/rand.h>
using std::remove_const;
using std::runtime_error;
using namespace erebos;
Ref ChannelRequestData::store(const Storage & st) const
{
vector<Record::Item> items;
for (const auto p : peers)
items.emplace_back("peer", p);
items.emplace_back("enc", "aes-128-gcm");
items.emplace_back("key", key);
return st.storeObject(Record(std::move(items)));
}
optional<ChannelRequestData> ChannelRequestData::load(const Ref & ref)
{
auto rec = ref->asRecord();
if (!rec)
return nullopt;
remove_const<decltype(peers)>::type peers;
for (const auto & i : rec->items("peer"))
if (auto p = i.as<Signed<IdentityData>>())
peers.push_back(*p);
auto enc = rec->item("enc").asText();
if (!enc || enc != "aes-128-gcm")
return nullopt;
auto key = rec->item("key").as<PublicKexKey>();
if (!key)
return nullopt;
return ChannelRequestData {
.peers = std::move(peers),
.key = *key,
};
}
Ref ChannelAcceptData::store(const Storage & st) const
{
vector<Record::Item> items;
items.emplace_back("req", request);
items.emplace_back("enc", "aes-128-gcm");
items.emplace_back("key", key);
return st.storeObject(Record(std::move(items)));
}
optional<ChannelAcceptData> ChannelAcceptData::load(const Ref & ref)
{
auto rec = ref->asRecord();
if (!rec)
return nullopt;
auto request = rec->item("req").as<ChannelRequest>();
if (!request)
return nullopt;
auto enc = rec->item("enc").asText();
if (!enc || enc != "aes-128-gcm")
return nullopt;
auto key = rec->item("key").as<PublicKexKey>();
if (!key)
return nullopt;
return ChannelAcceptData {
.request = *request,
.key = *key,
};
}
Stored<Channel> ChannelAcceptData::channel() const
{
const auto & st = request.ref.storage();
if (auto secret = SecretKexKey::load(key))
return st.store(Channel(
request->data->peers,
secret->dh(*request->data->key)
));
if (auto secret = SecretKexKey::load(request->data->key))
return st.store(Channel(
request->data->peers,
secret->dh(*key)
));
throw runtime_error("failed to load secret DH key");
}
Ref Channel::store(const Storage & st) const
{
vector<Record::Item> items;
for (const auto p : peers)
items.emplace_back("peer", p);
items.emplace_back("enc", "aes-128-gcm");
items.emplace_back("key", key);
return st.storeObject(Record(std::move(items)));
}
optional<Channel> Channel::load(const Ref & ref)
{
auto rec = ref->asRecord();
if (!rec)
return nullopt;
remove_const<decltype(peers)>::type peers;
for (const auto & i : rec->items("peer"))
if (auto p = i.as<Signed<IdentityData>>())
peers.push_back(*p);
auto enc = rec->item("enc").asText();
if (!enc || enc != "aes-128-gcm")
return nullopt;
auto key = rec->item("key").asBinary();
if (!key)
return nullopt;
return Channel(peers, std::move(*key));
}
Stored<ChannelRequest> Channel::generateRequest(const Storage & st,
const Identity & self, const Identity & peer)
{
auto signKey = SecretKey::load(self.keyMessage());
if (!signKey)
throw runtime_error("failed to load own message key");
return signKey->sign(st.store(ChannelRequestData {
.peers = self.ref()->digest() < peer.ref()->digest() ?
vector<Stored<Signed<IdentityData>>> {
*Stored<Signed<IdentityData>>::load(*self.ref()),
*Stored<Signed<IdentityData>>::load(*peer.ref()),
} :
vector<Stored<Signed<IdentityData>>> {
*Stored<Signed<IdentityData>>::load(*peer.ref()),
*Stored<Signed<IdentityData>>::load(*self.ref()),
},
.key = SecretKexKey::generate(st).pub(),
}));
}
optional<Stored<ChannelAccept>> Channel::acceptRequest(const Identity & self,
const Identity & peer, const Stored<ChannelRequest> & request)
{
if (!request->isSignedBy(peer.keyMessage()))
return nullopt;
auto & peers = request->data->peers;
if (peers.size() != 2 ||
std::none_of(peers.begin(), peers.end(), [&self](const auto & x)
{ return x.ref.digest() == self.ref()->digest(); }) ||
std::none_of(peers.begin(), peers.end(), [&peer](const auto & x)
{ return x.ref.digest() == peer.ref()->digest(); }))
return nullopt;
auto & st = request.ref.storage();
auto signKey = SecretKey::load(self.keyMessage());
if (!signKey)
throw runtime_error("failed to load own message key");
return signKey->sign(st.store(ChannelAcceptData {
.request = request,
.key = SecretKexKey::generate(st).pub(),
}));
}
vector<uint8_t> Channel::encrypt(const vector<uint8_t> & plain) const
{
vector<uint8_t> res(plain.size() + 12 + 16 + 16);
if (RAND_bytes(res.data(), 12) != 1)
throw runtime_error("failed to generate random IV");
const unique_ptr<EVP_CIPHER_CTX, void(*)(EVP_CIPHER_CTX*)>
ctx(EVP_CIPHER_CTX_new(), EVP_CIPHER_CTX_free);
EVP_EncryptInit_ex(ctx.get(), EVP_aes_128_gcm(),
nullptr, key.data(), res.data());
int outl = 0;
uint8_t * cur = res.data() + 12;
if (EVP_EncryptUpdate(ctx.get(), cur, &outl, plain.data(), plain.size()) != 1)
throw runtime_error("failed to encrypt data");
cur += outl;
if (EVP_EncryptFinal(ctx.get(), cur, &outl) != 1)
throw runtime_error("failed to encrypt data");
cur += outl;
EVP_CIPHER_CTX_ctrl(ctx.get(), EVP_CTRL_GCM_GET_TAG, 16, cur);
cur += 16;
res.resize(cur - res.data());
return res;
}
optional<vector<uint8_t>> Channel::decrypt(const vector<uint8_t> & ctext) const
{
vector<uint8_t> res(ctext.size());
const unique_ptr<EVP_CIPHER_CTX, void(*)(EVP_CIPHER_CTX*)>
ctx(EVP_CIPHER_CTX_new(), EVP_CIPHER_CTX_free);
EVP_DecryptInit_ex(ctx.get(), EVP_aes_128_gcm(),
nullptr, key.data(), ctext.data());
int outl = 0;
uint8_t * cur = res.data();
if (EVP_DecryptUpdate(ctx.get(), cur, &outl,
ctext.data() + 12, ctext.size() - 12 - 16) != 1)
return nullopt;
cur += outl;
if (!EVP_CIPHER_CTX_ctrl(ctx.get(), EVP_CTRL_GCM_SET_TAG, 16,
(void *) (ctext.data() + ctext.size() - 16)))
return nullopt;
if (EVP_DecryptFinal_ex(ctx.get(), cur, &outl) != 1)
return nullopt;
cur += outl;
res.resize(cur - res.data());
return res;
}
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