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-rw-r--r--src/ratchet.cpp36
1 files changed, 9 insertions, 27 deletions
diff --git a/src/ratchet.cpp b/src/ratchet.cpp
index abcc8a1..dd1d42c 100644
--- a/src/ratchet.cpp
+++ b/src/ratchet.cpp
@@ -66,7 +66,6 @@ static void create_chain_key(
static void advance_chain_key(
- std::uint32_t chain_index,
olm::ChainKey const & chain_key,
olm::ChainKey & new_chain_key
) {
@@ -80,7 +79,6 @@ static void advance_chain_key(
static void create_message_keys(
- std::uint32_t chain_index,
olm::ChainKey const & chain_key,
olm::KdfInfo const & info,
olm::MessageKey & message_key) {
@@ -111,7 +109,6 @@ static std::size_t verify_mac_and_decrypt(
static std::size_t verify_mac_and_decrypt_for_existing_chain(
olm::Ratchet const & session,
- std::uint32_t chain_index,
olm::ChainKey const & chain,
olm::MessageReader const & reader,
std::uint8_t * plaintext, std::size_t max_plaintext_length
@@ -128,11 +125,11 @@ static std::size_t verify_mac_and_decrypt_for_existing_chain(
olm::ChainKey new_chain = chain;
while (new_chain.index < reader.counter) {
- advance_chain_key(chain_index, new_chain, new_chain);
+ advance_chain_key(new_chain, new_chain);
}
olm::MessageKey message_key;
- create_message_keys(chain_index, new_chain, session.kdf_info, message_key);
+ create_message_keys(new_chain, session.kdf_info, message_key);
std::size_t result = verify_mac_and_decrypt(
session.ratchet_cipher, message_key, reader,
@@ -164,14 +161,13 @@ static std::size_t verify_mac_and_decrypt_for_new_chain(
}
olm::load_array(new_chain.ratchet_key.public_key, reader.ratchet_key);
- std::uint32_t chain_index = session.chain_index + 1;
create_chain_key(
session.root_key, session.sender_chain[0].ratchet_key,
new_chain.ratchet_key, session.kdf_info,
new_root_key, new_chain.chain_key
);
std::size_t result = verify_mac_and_decrypt_for_existing_chain(
- session, chain_index, new_chain.chain_key, reader,
+ session, new_chain.chain_key, reader,
plaintext, max_plaintext_length
);
olm::unset(new_root_key);
@@ -208,7 +204,6 @@ void olm::Ratchet::initialise_as_bob(
pos = olm::load_array(root_key, pos);
pos = olm::load_array(receiver_chains[0].chain_key.key, pos);
receiver_chains[0].ratchet_key = their_ratchet_key;
- chain_index = 0;
olm::unset(derived_secrets);
}
@@ -230,7 +225,6 @@ void olm::Ratchet::initialise_as_alice(
pos = olm::load_array(root_key, pos);
pos = olm::load_array(sender_chain[0].chain_key.key, pos);
sender_chain[0].ratchet_key = our_ratchet_key;
- chain_index = 0;
olm::unset(derived_secrets);
}
@@ -369,7 +363,6 @@ std::size_t olm::pickle_length(
length += olm::pickle_length(value.sender_chain);
length += olm::pickle_length(value.receiver_chains);
length += olm::pickle_length(value.skipped_message_keys);
- length += olm::pickle_length(value.chain_index);
return length;
}
@@ -381,7 +374,6 @@ std::uint8_t * olm::pickle(
pos = pickle(pos, value.sender_chain);
pos = pickle(pos, value.receiver_chains);
pos = pickle(pos, value.skipped_message_keys);
- pos = pickle(pos, value.chain_index);
return pos;
}
@@ -394,7 +386,6 @@ std::uint8_t const * olm::unpickle(
pos = unpickle(pos, end, value.sender_chain);
pos = unpickle(pos, end, value.receiver_chains);
pos = unpickle(pos, end, value.skipped_message_keys);
- pos = unpickle(pos, end, value.chain_index);
return pos;
}
@@ -447,12 +438,11 @@ std::size_t olm::Ratchet::encrypt(
kdf_info,
root_key, sender_chain[0].chain_key
);
- chain_index++;
}
MessageKey keys;
- create_message_keys(chain_index, sender_chain[0].chain_key, kdf_info, keys);
- advance_chain_key(chain_index, sender_chain[0].chain_key, sender_chain[0].chain_key);
+ create_message_keys(sender_chain[0].chain_key, kdf_info, keys);
+ advance_chain_key(sender_chain[0].chain_key, sender_chain[0].chain_key);
std::size_t ciphertext_length = ratchet_cipher->ops->encrypt_ciphertext_length(
ratchet_cipher,
@@ -538,12 +528,6 @@ std::size_t olm::Ratchet::decrypt(
}
ReceiverChain * chain = nullptr;
- auto receiver_chain_index = chain_index;
- if (!sender_chain.empty()) {
- // we've already advanced to the next (sender) chain; decrement to
- // get back to the receiver chains
- receiver_chain_index --;
- }
for (olm::ReceiverChain & receiver_chain : receiver_chains) {
if (0 == std::memcmp(
@@ -553,7 +537,6 @@ std::size_t olm::Ratchet::decrypt(
chain = &receiver_chain;
break;
}
- receiver_chain_index -= 2;
}
std::size_t result = std::size_t(-1);
@@ -590,7 +573,7 @@ std::size_t olm::Ratchet::decrypt(
}
} else {
result = verify_mac_and_decrypt_for_existing_chain(
- *this, receiver_chain_index, chain->chain_key,
+ *this, chain->chain_key,
reader, plaintext, max_plaintext_length
);
}
@@ -618,17 +601,16 @@ std::size_t olm::Ratchet::decrypt(
olm::unset(sender_chain[0]);
sender_chain.erase(sender_chain.begin());
- receiver_chain_index = ++chain_index;
}
while (chain->chain_key.index < reader.counter) {
olm::SkippedMessageKey & key = *skipped_message_keys.insert();
- create_message_keys(receiver_chain_index, chain->chain_key, kdf_info, key.message_key);
+ create_message_keys(chain->chain_key, kdf_info, key.message_key);
key.ratchet_key = chain->ratchet_key;
- advance_chain_key(receiver_chain_index, chain->chain_key, chain->chain_key);
+ advance_chain_key(chain->chain_key, chain->chain_key);
}
- advance_chain_key(receiver_chain_index, chain->chain_key, chain->chain_key);
+ advance_chain_key(chain->chain_key, chain->chain_key);
return result;
}