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Remove unused 'chain_index' from Ratchet

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This was introduced when I was experimenting with support for logging progress
in Olm. That is now relegated to the logging_enabled branch, so this should
probably be removed.

This also fixes the incompatibility of session pickles from the current master
branch with those from olm 0.1.0.
This commit is contained in:
Richard van der Hoff 2016-06-28 16:45:31 +01:00
parent 803672931a
commit 757c422578
3 changed files with 37 additions and 50 deletions
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10
include/olm/ratchet.hh
View file

@ -81,16 +81,6 @@ struct Ratchet {
/** The last error that happened encrypting or decrypting a message. */ /** The last error that happened encrypting or decrypting a message. */
OlmErrorCode last_error; OlmErrorCode last_error;
/**
* A count of the number of times the root key has been advanced; this is
* maintained purely for diagnostics.
*
* If sender_chain is empty, this will be the index of the current receiver
* chain (odd for Alice, even for Bob); otherwise, the index of the current
* sender chain (even for Alice, odd for Bob).
*/
std::uint32_t chain_index;
/** The root key is used to generate chain keys from the ephemeral keys. /** The root key is used to generate chain keys from the ephemeral keys.
* A new root_key derived each time a new chain is started. */ * A new root_key derived each time a new chain is started. */
SharedKey root_key; SharedKey root_key;

36
src/ratchet.cpp
View file

@ -66,7 +66,6 @@ static void create_chain_key(
static void advance_chain_key( static void advance_chain_key(
std::uint32_t chain_index,
olm::ChainKey const & chain_key, olm::ChainKey const & chain_key,
olm::ChainKey & new_chain_key olm::ChainKey & new_chain_key
) { ) {
@ -80,7 +79,6 @@ static void advance_chain_key(
static void create_message_keys( static void create_message_keys(
std::uint32_t chain_index,
olm::ChainKey const & chain_key, olm::ChainKey const & chain_key,
olm::KdfInfo const & info, olm::KdfInfo const & info,
olm::MessageKey & message_key) { 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( static std::size_t verify_mac_and_decrypt_for_existing_chain(
olm::Ratchet const & session, olm::Ratchet const & session,
std::uint32_t chain_index,
olm::ChainKey const & chain, olm::ChainKey const & chain,
olm::MessageReader const & reader, olm::MessageReader const & reader,
std::uint8_t * plaintext, std::size_t max_plaintext_length 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; olm::ChainKey new_chain = chain;
while (new_chain.index < reader.counter) { 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; 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( std::size_t result = verify_mac_and_decrypt(
session.ratchet_cipher, message_key, reader, 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); olm::load_array(new_chain.ratchet_key.public_key, reader.ratchet_key);
std::uint32_t chain_index = session.chain_index + 1;
create_chain_key( create_chain_key(
session.root_key, session.sender_chain[0].ratchet_key, session.root_key, session.sender_chain[0].ratchet_key,
new_chain.ratchet_key, session.kdf_info, new_chain.ratchet_key, session.kdf_info,
new_root_key, new_chain.chain_key new_root_key, new_chain.chain_key
); );
std::size_t result = verify_mac_and_decrypt_for_existing_chain( 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 plaintext, max_plaintext_length
); );
olm::unset(new_root_key); 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(root_key, pos);
pos = olm::load_array(receiver_chains[0].chain_key.key, pos); pos = olm::load_array(receiver_chains[0].chain_key.key, pos);
receiver_chains[0].ratchet_key = their_ratchet_key; receiver_chains[0].ratchet_key = their_ratchet_key;
chain_index = 0;
olm::unset(derived_secrets); 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(root_key, pos);
pos = olm::load_array(sender_chain[0].chain_key.key, pos); pos = olm::load_array(sender_chain[0].chain_key.key, pos);
sender_chain[0].ratchet_key = our_ratchet_key; sender_chain[0].ratchet_key = our_ratchet_key;
chain_index = 0;
olm::unset(derived_secrets); 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.sender_chain);
length += olm::pickle_length(value.receiver_chains); length += olm::pickle_length(value.receiver_chains);
length += olm::pickle_length(value.skipped_message_keys); length += olm::pickle_length(value.skipped_message_keys);
length += olm::pickle_length(value.chain_index);
return length; return length;
} }
@ -381,7 +374,6 @@ std::uint8_t * olm::pickle(
pos = pickle(pos, value.sender_chain); pos = pickle(pos, value.sender_chain);
pos = pickle(pos, value.receiver_chains); pos = pickle(pos, value.receiver_chains);
pos = pickle(pos, value.skipped_message_keys); pos = pickle(pos, value.skipped_message_keys);
pos = pickle(pos, value.chain_index);
return pos; return pos;
} }
@ -394,7 +386,6 @@ std::uint8_t const * olm::unpickle(
pos = unpickle(pos, end, value.sender_chain); pos = unpickle(pos, end, value.sender_chain);
pos = unpickle(pos, end, value.receiver_chains); pos = unpickle(pos, end, value.receiver_chains);
pos = unpickle(pos, end, value.skipped_message_keys); pos = unpickle(pos, end, value.skipped_message_keys);
pos = unpickle(pos, end, value.chain_index);
return pos; return pos;
} }
@ -447,12 +438,11 @@ std::size_t olm::Ratchet::encrypt(
kdf_info, kdf_info,
root_key, sender_chain[0].chain_key root_key, sender_chain[0].chain_key
); );
chain_index++;
} }
MessageKey keys; MessageKey keys;
create_message_keys(chain_index, sender_chain[0].chain_key, kdf_info, keys); create_message_keys(sender_chain[0].chain_key, kdf_info, keys);
advance_chain_key(chain_index, sender_chain[0].chain_key, sender_chain[0].chain_key); advance_chain_key(sender_chain[0].chain_key, sender_chain[0].chain_key);
std::size_t ciphertext_length = ratchet_cipher->ops->encrypt_ciphertext_length( std::size_t ciphertext_length = ratchet_cipher->ops->encrypt_ciphertext_length(
ratchet_cipher, ratchet_cipher,
@ -538,12 +528,6 @@ std::size_t olm::Ratchet::decrypt(
} }
ReceiverChain * chain = nullptr; 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) { for (olm::ReceiverChain & receiver_chain : receiver_chains) {
if (0 == std::memcmp( if (0 == std::memcmp(
@ -553,7 +537,6 @@ std::size_t olm::Ratchet::decrypt(
chain = &receiver_chain; chain = &receiver_chain;
break; break;
} }
receiver_chain_index -= 2;
} }
std::size_t result = std::size_t(-1); std::size_t result = std::size_t(-1);
@ -590,7 +573,7 @@ std::size_t olm::Ratchet::decrypt(
} }
} else { } else {
result = verify_mac_and_decrypt_for_existing_chain( result = verify_mac_and_decrypt_for_existing_chain(
*this, receiver_chain_index, chain->chain_key, *this, chain->chain_key,
reader, plaintext, max_plaintext_length reader, plaintext, max_plaintext_length
); );
} }
@ -618,17 +601,16 @@ std::size_t olm::Ratchet::decrypt(
olm::unset(sender_chain[0]); olm::unset(sender_chain[0]);
sender_chain.erase(sender_chain.begin()); sender_chain.erase(sender_chain.begin());
receiver_chain_index = ++chain_index;
} }
while (chain->chain_key.index < reader.counter) { while (chain->chain_key.index < reader.counter) {
olm::SkippedMessageKey & key = *skipped_message_keys.insert(); 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; 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; return result;
} }

41
tests/test_olm_decrypt.cpp
View file

@ -1,11 +1,16 @@
#include "olm/olm.h" #include "olm/olm.h"
#include "unittest.hh" #include "unittest.hh"
const char * test_cases[] = { struct test_case {
"41776f", const char *msghex;
"7fff6f0101346d671201", const char *expected_error;
"ee776f41496f674177804177778041776f6716670a677d6f670a67c2677d", };
"e9e9c9c1e9e9c9e9c9c1e9e9c9c1",
const test_case test_cases[] = {
{ "41776f", "BAD_MESSAGE_FORMAT" },
{ "7fff6f0101346d671201", "BAD_MESSAGE_FORMAT" },
{ "ee776f41496f674177804177778041776f6716670a677d6f670a67c2677d", "BAD_MESSAGE_FORMAT" },
{ "e9e9c9c1e9e9c9e9c9c1e9e9c9c1", "BAD_MESSAGE_FORMAT" },
}; };
@ -31,29 +36,39 @@ void decode_hex(
} }
} }
void decrypt_case(int message_type, const char * test_case) { void decrypt_case(int message_type, const test_case * test_case) {
std::uint8_t session_memory[olm_session_size()]; std::uint8_t session_memory[olm_session_size()];
::OlmSession * session = ::olm_session(session_memory); ::OlmSession * session = ::olm_session(session_memory);
std::uint8_t pickled[strlen(session_data)]; std::uint8_t pickled[strlen(session_data)];
::memcpy(pickled, session_data, sizeof(pickled)); ::memcpy(pickled, session_data, sizeof(pickled));
::olm_unpickle_session(session, "", 0, pickled, sizeof(pickled)); assert_not_equals(
::olm_error(),
::olm_unpickle_session(session, "", 0, pickled, sizeof(pickled))
);
std::size_t message_length = strlen(test_case) / 2; std::size_t message_length = strlen(test_case->msghex) / 2;
std::uint8_t * message = (std::uint8_t *) ::malloc(message_length); std::uint8_t * message = (std::uint8_t *) ::malloc(message_length);
decode_hex(test_case, message, message_length); decode_hex(test_case->msghex, message, message_length);
size_t max_length = olm_decrypt_max_plaintext_length( size_t max_length = olm_decrypt_max_plaintext_length(
session, message_type, message, message_length session, message_type, message, message_length
); );
if (max_length == std::size_t(-1)) { if (test_case->expected_error) {
assert_equals(::olm_error(), max_length);
assert_equals(
std::string(test_case->expected_error),
std::string(::olm_session_last_error(session))
);
free(message); free(message);
return; return;
} }
assert_not_equals(::olm_error(), max_length);
uint8_t plaintext[max_length]; uint8_t plaintext[max_length];
decode_hex(test_case, message, message_length); decode_hex(test_case->msghex, message, message_length);
olm_decrypt( olm_decrypt(
session, message_type, session, message_type,
message, message_length, message, message_length,
@ -67,8 +82,8 @@ int main() {
{ {
TestCase my_test("Olm decrypt test"); TestCase my_test("Olm decrypt test");
for (unsigned int i = 0; i < sizeof(test_cases)/ sizeof(const char *); ++i) { for (unsigned int i = 0; i < sizeof(test_cases)/ sizeof(test_cases[0]); ++i) {
decrypt_case(0, test_cases[i]); decrypt_case(0, &test_cases[i]);
} }
} }