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-rw-r--r--src/network/channel.cpp74
-rw-r--r--src/network/channel.h11
2 files changed, 49 insertions, 36 deletions
diff --git a/src/network/channel.cpp b/src/network/channel.cpp
index b95e0a1..5fff1fa 100644
--- a/src/network/channel.cpp
+++ b/src/network/channel.cpp
@@ -17,7 +17,6 @@ Ref ChannelRequestData::store(const Storage & st) const
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)));
@@ -26,12 +25,11 @@ Ref ChannelRequestData::store(const Storage & st) const
ChannelRequestData ChannelRequestData::load(const Ref & ref)
{
if (auto rec = ref->asRecord()) {
- if (rec->item("enc").asText() == "aes-128-gcm")
- if (auto key = rec->item("key").as<PublicKexKey>())
- return ChannelRequestData {
- .peers = rec->items("peer").as<Signed<IdentityData>>(),
- .key = *key,
- };
+ if (auto key = rec->item("key").as<PublicKexKey>())
+ return ChannelRequestData {
+ .peers = rec->items("peer").as<Signed<IdentityData>>(),
+ .key = *key,
+ };
}
return ChannelRequestData {
@@ -45,7 +43,6 @@ 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)));
@@ -54,11 +51,10 @@ Ref ChannelAcceptData::store(const Storage & st) const
ChannelAcceptData ChannelAcceptData::load(const Ref & ref)
{
if (auto rec = ref->asRecord())
- if (rec->item("enc").asText() == "aes-128-gcm")
- return ChannelAcceptData {
- .request = *rec->item("req").as<ChannelRequest>(),
- .key = *rec->item("key").as<PublicKexKey>(),
- };
+ return ChannelAcceptData {
+ .request = *rec->item("req").as<ChannelRequest>(),
+ .key = *rec->item("key").as<PublicKexKey>(),
+ };
return ChannelAcceptData {
.request = Stored<ChannelRequest>::load(ref.storage().zref()),
@@ -137,21 +133,26 @@ uint64_t Channel::encrypt(BufferCIt plainBegin, BufferCIt plainEnd,
Buffer & encBuffer, size_t encOffset)
{
auto plainSize = plainEnd - plainBegin;
- encBuffer.resize(encOffset + plainSize + 8 + 16 + 16);
+ encBuffer.resize(encOffset + plainSize + 1 /* counter */ + 16 /* tag */);
array<uint8_t, 12> iv;
- uint64_t beCount = htobe64(nonceCounter++);
- std::memcpy(encBuffer.data() + encOffset, &beCount, 8);
- std::copy_n(nonceFixedOur.begin(), 6, iv.begin());
- std::copy_n(encBuffer.begin() + encOffset + 2, 6, iv.begin() + 6);
+ uint64_t count = counterNextOut.fetch_add(1);
+ uint64_t beCount = htobe64(count);
+ encBuffer[encOffset] = count % 0x100;
+
+ constexpr size_t nonceFixedSize = std::tuple_size_v<decltype(nonceFixedOur)>;
+ static_assert(nonceFixedSize + sizeof beCount == iv.size());
+
+ std::copy_n(nonceFixedOur.begin(), nonceFixedSize, iv.begin());
+ std::memcpy(iv.data() + nonceFixedSize, &beCount, sizeof beCount);
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(),
+ EVP_EncryptInit_ex(ctx.get(), EVP_chacha20_poly1305(),
nullptr, key.data(), iv.data());
int outl = 0;
- uint8_t * cur = encBuffer.data() + encOffset + 8;
+ uint8_t * cur = encBuffer.data() + encOffset + 1;
if (EVP_EncryptUpdate(ctx.get(), cur, &outl, &*plainBegin, plainSize) != 1)
throw runtime_error("failed to encrypt data");
@@ -161,11 +162,8 @@ uint64_t Channel::encrypt(BufferCIt plainBegin, BufferCIt plainEnd,
throw runtime_error("failed to encrypt data");
cur += outl;
- EVP_CIPHER_CTX_ctrl(ctx.get(), EVP_CTRL_GCM_GET_TAG, 16, cur);
- cur += 16;
-
- encBuffer.resize(cur - encBuffer.data());
- return 0;
+ EVP_CIPHER_CTX_ctrl(ctx.get(), EVP_CTRL_AEAD_GET_TAG, 16, cur);
+ return count;
}
optional<uint64_t> Channel::decrypt(BufferCIt encBegin, BufferCIt encEnd,
@@ -175,23 +173,33 @@ optional<uint64_t> Channel::decrypt(BufferCIt encBegin, BufferCIt encEnd,
decBuffer.resize(decOffset + encSize);
array<uint8_t, 12> iv;
- std::copy_n(nonceFixedPeer.begin(), 6, iv.begin());
- std::copy_n(encBegin + 2, 6, iv.begin() + 6);
+ if (encBegin + 1 /* counter */ + 16 /* tag */ > encEnd)
+ return nullopt;
+
+ uint64_t expectedCount = counterNextIn.load();
+ uint64_t guessedCount = expectedCount - 0x80u + ((0x80u + encBegin[0] - expectedCount) % 0x100u);
+ uint64_t beCount = htobe64(guessedCount);
+
+ constexpr size_t nonceFixedSize = std::tuple_size_v<decltype(nonceFixedPeer)>;
+ static_assert(nonceFixedSize + sizeof beCount == iv.size());
+
+ std::copy_n(nonceFixedPeer.begin(), nonceFixedSize, iv.begin());
+ std::memcpy(iv.data() + nonceFixedSize, &beCount, sizeof beCount);
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(),
+ EVP_DecryptInit_ex(ctx.get(), EVP_chacha20_poly1305(),
nullptr, key.data(), iv.data());
int outl = 0;
uint8_t * cur = decBuffer.data() + decOffset;
if (EVP_DecryptUpdate(ctx.get(), cur, &outl,
- &*encBegin + 8, encSize - 8 - 16) != 1)
+ &*encBegin + 1, encSize - 1 - 16) != 1)
return nullopt;
cur += outl;
- if (!EVP_CIPHER_CTX_ctrl(ctx.get(), EVP_CTRL_GCM_SET_TAG, 16,
+ if (!EVP_CIPHER_CTX_ctrl(ctx.get(), EVP_CTRL_AEAD_SET_TAG, 16,
(void *) (&*encEnd - 16)))
return nullopt;
@@ -199,6 +207,10 @@ optional<uint64_t> Channel::decrypt(BufferCIt encBegin, BufferCIt encEnd,
return nullopt;
cur += outl;
+ while (expectedCount < guessedCount + 1 &&
+ not counterNextIn.compare_exchange_weak(expectedCount, guessedCount + 1))
+ ; // empty loop body
+
decBuffer.resize(cur - decBuffer.data());
- return 0;
+ return guessedCount;
}
diff --git a/src/network/channel.h b/src/network/channel.h
index 98bfd29..bba11b3 100644
--- a/src/network/channel.h
+++ b/src/network/channel.h
@@ -44,8 +44,8 @@ public:
vector<uint8_t> && key, bool ourRequest):
peers(peers),
key(std::move(key)),
- nonceFixedOur({ uint8_t(ourRequest ? 1 : 2), 0, 0, 0, 0, 0 }),
- nonceFixedPeer({ uint8_t(ourRequest ? 2 : 1), 0, 0, 0, 0, 0 })
+ nonceFixedOur({ uint8_t(ourRequest ? 1 : 2), 0, 0, 0 }),
+ nonceFixedPeer({ uint8_t(ourRequest ? 2 : 1), 0, 0, 0 })
{}
Channel(const Channel &) = delete;
@@ -69,9 +69,10 @@ private:
const vector<Stored<Signed<IdentityData>>> peers;
const vector<uint8_t> key;
- const array<uint8_t, 6> nonceFixedOur;
- const array<uint8_t, 6> nonceFixedPeer;
- atomic<uint64_t> nonceCounter = 0;
+ const array<uint8_t, 4> nonceFixedOur;
+ const array<uint8_t, 4> nonceFixedPeer;
+ atomic<uint64_t> counterNextOut = 0;
+ atomic<uint64_t> counterNextIn = 0;
};
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-29 08:28:56 +0000