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Store a flag indicating if the sender key is verified

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This commit is contained in:
Richard van der Hoff 2017-01-10 10:57:14 +00:00
parent a2f0c93a93
commit fc72c732fd
1 changed files with 36 additions and 7 deletions
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39
src/inbound_group_session.c
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@ -30,7 +30,7 @@
#define OLM_PROTOCOL_VERSION 3
#define GROUP_SESSION_ID_LENGTH ED25519_PUBLIC_KEY_LENGTH
#define PICKLE_VERSION 1
#define PICKLE_VERSION 2
#define SESSION_KEY_VERSION 2
#define SESSION_EXPORT_VERSION 1
@ -44,6 +44,17 @@ struct OlmInboundGroupSession {
/** The ed25519 signing key */
struct _olm_ed25519_public_key signing_key;
/**
* Have we ever seen any evidence that this is a valid session?
* (either because the original session share was signed, or because we
* have subsequently successfully decrypted a message?)
*
* (We don't do anything with this currently, but we may want to bear it in
* mind when we consider handling key-shares for sessions we already know
* about.)
*/
int signing_key_verified;
enum OlmErrorCode last_error;
};
@ -109,12 +120,16 @@ static size_t _init_group_session_keys(
);
ptr += ED25519_PUBLIC_KEY_LENGTH;
if (!export_format && !_olm_crypto_ed25519_verify(
&session->signing_key, key_buf, ptr - key_buf, ptr
)) {
if (!export_format) {
if (!_olm_crypto_ed25519_verify(&session->signing_key, key_buf,
ptr - key_buf, ptr)) {
session->last_error = OLM_BAD_SIGNATURE;
return (size_t)-1;
}
/* signed keyshare */
session->signing_key_verified = 1;
}
return 0;
}
@ -174,6 +189,7 @@ static size_t raw_pickle_length(
length += megolm_pickle_length(&session->initial_ratchet);
length += megolm_pickle_length(&session->latest_ratchet);
length += _olm_pickle_ed25519_public_key_length(&session->signing_key);
length += _olm_pickle_bool_length(session->signing_key_verified);
return length;
}
@ -201,6 +217,7 @@ size_t olm_pickle_inbound_group_session(
pos = megolm_pickle(&session->initial_ratchet, pos);
pos = megolm_pickle(&session->latest_ratchet, pos);
pos = _olm_pickle_ed25519_public_key(pos, &session->signing_key);
pos = _olm_pickle_bool(pos, session->signing_key_verified);
return _olm_enc_output(key, key_length, pickled, raw_length);
}
@ -224,7 +241,7 @@ size_t olm_unpickle_inbound_group_session(
pos = pickled;
end = pos + raw_length;
pos = _olm_unpickle_uint32(pos, end, &pickle_version);
if (pickle_version != PICKLE_VERSION) {
if (pickle_version < 1 || pickle_version > PICKLE_VERSION) {
session->last_error = OLM_UNKNOWN_PICKLE_VERSION;
return (size_t)-1;
}
@ -232,6 +249,14 @@ size_t olm_unpickle_inbound_group_session(
pos = megolm_unpickle(&session->latest_ratchet, pos, end);
pos = _olm_unpickle_ed25519_public_key(pos, end, &session->signing_key);
if (pickle_version == 1) {
/* pickle v1 had no signing_key_verified field (all keyshares were
* verified at import time) */
session->signing_key_verified = 1;
} else {
pos = _olm_unpickle_bool(pos, end, &(session->signing_key_verified));
}
if (end != pos) {
/* We had the wrong number of bytes in the input. */
session->last_error = OLM_CORRUPTED_PICKLE;
@ -391,6 +416,10 @@ static size_t _decrypt(
return r;
}
/* once we have successfully decrypted a message, set a flag to say the
* session appears valid. */
session->signing_key_verified = 1;
return r;
}