Merge pull request #21 from matrix-org/markjh/fix_session_ids
Use the ed25519 public key as the group session id.
This commit is contained in:
commit
e0b51971b7
3 changed files with 48 additions and 35 deletions
|
@ -30,7 +30,7 @@
|
|||
|
||||
#define OLM_PROTOCOL_VERSION 3
|
||||
#define PICKLE_VERSION 1
|
||||
#define SESSION_KEY_VERSION 1
|
||||
#define SESSION_KEY_VERSION 2
|
||||
|
||||
struct OlmInboundGroupSession {
|
||||
/** our earliest known ratchet value */
|
||||
|
@ -71,12 +71,12 @@ size_t olm_clear_inbound_group_session(
|
|||
}
|
||||
|
||||
#define SESSION_KEY_RAW_LENGTH \
|
||||
(1 + MEGOLM_RATCHET_LENGTH + ED25519_PUBLIC_KEY_LENGTH)
|
||||
(1 + 4 + MEGOLM_RATCHET_LENGTH + ED25519_PUBLIC_KEY_LENGTH\
|
||||
+ ED25519_SIGNATURE_LENGTH)
|
||||
|
||||
/** init the session keys from the un-base64-ed session keys */
|
||||
static size_t _init_group_session_keys(
|
||||
OlmInboundGroupSession *session,
|
||||
uint32_t message_index,
|
||||
const uint8_t *key_buf
|
||||
) {
|
||||
const uint8_t *ptr = key_buf;
|
||||
|
@ -87,13 +87,27 @@ static size_t _init_group_session_keys(
|
|||
return (size_t)-1;
|
||||
}
|
||||
|
||||
megolm_init(&session->initial_ratchet, ptr, message_index);
|
||||
megolm_init(&session->latest_ratchet, ptr, message_index);
|
||||
uint32_t counter = 0;
|
||||
// Decode counter as a big endian 32-bit number.
|
||||
for (unsigned i = 0; i < 4; i++) {
|
||||
counter <<= 8; counter |= *ptr++;
|
||||
}
|
||||
|
||||
megolm_init(&session->initial_ratchet, ptr, counter);
|
||||
megolm_init(&session->latest_ratchet, ptr, counter);
|
||||
|
||||
ptr += MEGOLM_RATCHET_LENGTH;
|
||||
memcpy(
|
||||
session->signing_key.public_key, ptr, ED25519_PUBLIC_KEY_LENGTH
|
||||
);
|
||||
ptr += ED25519_PUBLIC_KEY_LENGTH;
|
||||
|
||||
if (!_olm_crypto_ed25519_verify(
|
||||
&session->signing_key, key_buf, ptr - key_buf, ptr
|
||||
)) {
|
||||
session->last_error = OLM_BAD_SIGNATURE;
|
||||
return (size_t)-1;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
@ -117,7 +131,7 @@ size_t olm_init_inbound_group_session(
|
|||
}
|
||||
|
||||
_olm_decode_base64(session_key, session_key_length, key_buf);
|
||||
result = _init_group_session_keys(session, message_index, key_buf);
|
||||
result = _init_group_session_keys(session, key_buf);
|
||||
_olm_unset(key_buf, SESSION_KEY_RAW_LENGTH);
|
||||
return result;
|
||||
}
|
||||
|
@ -288,7 +302,6 @@ static size_t _decrypt(
|
|||
return (size_t)-1;
|
||||
}
|
||||
|
||||
|
||||
max_length = megolm_cipher->ops->decrypt_max_plaintext_length(
|
||||
megolm_cipher,
|
||||
decoded_results.ciphertext_length
|
||||
|
|
|
@ -29,10 +29,9 @@
|
|||
#include "olm/pickle_encoding.h"
|
||||
|
||||
#define OLM_PROTOCOL_VERSION 3
|
||||
#define SESSION_ID_RANDOM_BYTES 4
|
||||
#define GROUP_SESSION_ID_LENGTH (sizeof(struct timeval) + SESSION_ID_RANDOM_BYTES)
|
||||
#define GROUP_SESSION_ID_LENGTH ED25519_PUBLIC_KEY_LENGTH
|
||||
#define PICKLE_VERSION 1
|
||||
#define SESSION_KEY_VERSION 1
|
||||
#define SESSION_KEY_VERSION 2
|
||||
|
||||
struct OlmOutboundGroupSession {
|
||||
/** the Megolm ratchet providing the encryption keys */
|
||||
|
@ -41,9 +40,6 @@ struct OlmOutboundGroupSession {
|
|||
/** The ed25519 keypair used for signing the messages */
|
||||
struct _olm_ed25519_key_pair signing_key;
|
||||
|
||||
/** unique identifier for this session */
|
||||
uint8_t session_id[GROUP_SESSION_ID_LENGTH];
|
||||
|
||||
enum OlmErrorCode last_error;
|
||||
};
|
||||
|
||||
|
@ -80,8 +76,6 @@ static size_t raw_pickle_length(
|
|||
length += _olm_pickle_uint32_length(PICKLE_VERSION);
|
||||
length += megolm_pickle_length(&(session->ratchet));
|
||||
length += _olm_pickle_ed25519_key_pair_length(&(session->signing_key));
|
||||
length += _olm_pickle_bytes_length(session->session_id,
|
||||
GROUP_SESSION_ID_LENGTH);
|
||||
return length;
|
||||
}
|
||||
|
||||
|
@ -108,7 +102,6 @@ size_t olm_pickle_outbound_group_session(
|
|||
pos = _olm_pickle_uint32(pos, PICKLE_VERSION);
|
||||
pos = megolm_pickle(&(session->ratchet), pos);
|
||||
pos = _olm_pickle_ed25519_key_pair(pos, &(session->signing_key));
|
||||
pos = _olm_pickle_bytes(pos, session->session_id, GROUP_SESSION_ID_LENGTH);
|
||||
|
||||
return _olm_enc_output(key, key_length, pickled, raw_length);
|
||||
}
|
||||
|
@ -138,7 +131,6 @@ size_t olm_unpickle_outbound_group_session(
|
|||
}
|
||||
pos = megolm_unpickle(&(session->ratchet), pos, end);
|
||||
pos = _olm_unpickle_ed25519_key_pair(pos, end, &(session->signing_key));
|
||||
pos = _olm_unpickle_bytes(pos, end, session->session_id, GROUP_SESSION_ID_LENGTH);
|
||||
|
||||
if (end != pos) {
|
||||
/* We had the wrong number of bytes in the input. */
|
||||
|
@ -157,8 +149,7 @@ size_t olm_init_outbound_group_session_random_length(
|
|||
* session id.
|
||||
*/
|
||||
return MEGOLM_RATCHET_LENGTH +
|
||||
ED25519_RANDOM_LENGTH +
|
||||
SESSION_ID_RANDOM_BYTES;
|
||||
ED25519_RANDOM_LENGTH;
|
||||
}
|
||||
|
||||
size_t olm_init_outbound_group_session(
|
||||
|
@ -177,13 +168,6 @@ size_t olm_init_outbound_group_session(
|
|||
_olm_crypto_ed25519_generate_key(random, &(session->signing_key));
|
||||
random += ED25519_RANDOM_LENGTH;
|
||||
|
||||
/* initialise the session id. This just has to be unique. We use the
|
||||
* current time plus some random data.
|
||||
*/
|
||||
gettimeofday((struct timeval *)(session->session_id), NULL);
|
||||
memcpy((session->session_id) + sizeof(struct timeval),
|
||||
random, SESSION_ID_RANDOM_BYTES);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
@ -314,7 +298,9 @@ size_t olm_outbound_group_session_id(
|
|||
return (size_t)-1;
|
||||
}
|
||||
|
||||
return _olm_encode_base64(session->session_id, GROUP_SESSION_ID_LENGTH, id);
|
||||
return _olm_encode_base64(
|
||||
session->signing_key.public_key.public_key, GROUP_SESSION_ID_LENGTH, id
|
||||
);
|
||||
}
|
||||
|
||||
uint32_t olm_outbound_group_session_message_index(
|
||||
|
@ -324,7 +310,8 @@ uint32_t olm_outbound_group_session_message_index(
|
|||
}
|
||||
|
||||
#define SESSION_KEY_RAW_LENGTH \
|
||||
(1 + MEGOLM_RATCHET_LENGTH + ED25519_PUBLIC_KEY_LENGTH)
|
||||
(1 + 4 + MEGOLM_RATCHET_LENGTH + ED25519_PUBLIC_KEY_LENGTH\
|
||||
+ ED25519_SIGNATURE_LENGTH)
|
||||
|
||||
size_t olm_outbound_group_session_key_length(
|
||||
const OlmOutboundGroupSession *session
|
||||
|
@ -349,6 +336,12 @@ size_t olm_outbound_group_session_key(
|
|||
raw = ptr = key + encoded_length - SESSION_KEY_RAW_LENGTH;
|
||||
*ptr++ = SESSION_KEY_VERSION;
|
||||
|
||||
uint32_t counter = session->ratchet.counter;
|
||||
// Encode counter as a big endian 32-bit number.
|
||||
for (unsigned i = 0; i < 4; i++) {
|
||||
*ptr++ = 0xFF & (counter >> 24); counter <<= 8;
|
||||
}
|
||||
|
||||
memcpy(ptr, megolm_get_data(&session->ratchet), MEGOLM_RATCHET_LENGTH);
|
||||
ptr += MEGOLM_RATCHET_LENGTH;
|
||||
|
||||
|
@ -358,5 +351,11 @@ size_t olm_outbound_group_session_key(
|
|||
);
|
||||
ptr += ED25519_PUBLIC_KEY_LENGTH;
|
||||
|
||||
/* sign the whole thing with the ed25519 key. */
|
||||
_olm_crypto_ed25519_sign(
|
||||
&(session->signing_key),
|
||||
raw, ptr - raw, ptr
|
||||
);
|
||||
|
||||
return _olm_encode_base64(raw, SESSION_KEY_RAW_LENGTH, key);
|
||||
}
|
||||
|
|
|
@ -97,7 +97,7 @@ int main() {
|
|||
uint8_t memory[size];
|
||||
OlmOutboundGroupSession *session = olm_outbound_group_session(memory);
|
||||
|
||||
assert_equals((size_t)164,
|
||||
assert_equals((size_t)160,
|
||||
olm_init_outbound_group_session_random_length(session));
|
||||
|
||||
size_t res = olm_init_outbound_group_session(
|
||||
|
@ -154,14 +154,15 @@ int main() {
|
|||
size_t plaintext_length = sizeof(plaintext) - 1;
|
||||
|
||||
uint8_t session_key[] =
|
||||
"ATAxMjM0NTY3ODlBQkRFRjAxMjM0NTY3ODlBQkNERUYwMTIzNDU2Nzg5QUJERUYw"
|
||||
"MTIzNDU2Nzg5QUJDREVGMDEyMzQ1Njc4OUFCREVGMDEyMzQ1Njc4OUFCQ0RFRjAx"
|
||||
"MjM0NTY3ODlBQkRFRjAxMjM0NTY3ODlBQkNERUYwMTIzDRt2DUEOrg/H+yUGjDTq"
|
||||
"ryf8H1YF/BZjI04HwOVSZcY";
|
||||
"AgAAAAAwMTIzNDU2Nzg5QUJERUYwMTIzNDU2Nzg5QUJDREVGMDEyMzQ1Njc4OUFCREVGM"
|
||||
"DEyMzQ1Njc4OUFCQ0RFRjAxMjM0NTY3ODlBQkRFRjAxMjM0NTY3ODlBQkNERUYwMTIzND"
|
||||
"U2Nzg5QUJERUYwMTIzNDU2Nzg5QUJDREVGMDEyMztqJ7zOtqQtYqOo0CpvDXNlMhV3HeJ"
|
||||
"DpjrASKGLWdop4lx1cSN3Xv1TgfLPW8rhGiW+hHiMxd36nRuxscNv9k4oJA/KP+o0mi1w"
|
||||
"v44StrEJ1wwx9WZHBUIWkQbaBSuBDw";
|
||||
|
||||
uint8_t message[] =
|
||||
"AwgAEhAcbh6UpbByoyZxufQ+h2B+8XHMjhR69G8F4+qjMaFlnIXusJZX3r8LnROR"
|
||||
"G9T3DXFdbVuvIWrLyRfm4i8QRbe8VPwGRFG57B1CtmxanuP8bHtnnYqlwPsD";
|
||||
"AwgAEhAcbh6UpbByoyZxufQ+h2B+8XHMjhR69G8nP4pNZGl/3QMgrzCZPmP+F2aPLyKPz"
|
||||
"xRPBMUkeXRJ6Iqm5NeOdx2eERgTW7P20CM+lL3Xpk+ZUOOPvsSQNaAL";
|
||||
size_t msglen = sizeof(message)-1;
|
||||
|
||||
/* build the inbound session */
|
||||
|
|
Loading…
Reference in a new issue