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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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43
src/inbound_group_session.c
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@ -30,7 +30,7 @@
#define OLM_PROTOCOL_VERSION 3 #define OLM_PROTOCOL_VERSION 3
#define GROUP_SESSION_ID_LENGTH ED25519_PUBLIC_KEY_LENGTH #define GROUP_SESSION_ID_LENGTH ED25519_PUBLIC_KEY_LENGTH
#define PICKLE_VERSION 1 #define PICKLE_VERSION 2
#define SESSION_KEY_VERSION 2 #define SESSION_KEY_VERSION 2
#define SESSION_EXPORT_VERSION 1 #define SESSION_EXPORT_VERSION 1
@ -44,6 +44,17 @@ struct OlmInboundGroupSession {
/** The ed25519 signing key */ /** The ed25519 signing key */
struct _olm_ed25519_public_key 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; enum OlmErrorCode last_error;
}; };
@ -109,11 +120,15 @@ static size_t _init_group_session_keys(
); );
ptr += ED25519_PUBLIC_KEY_LENGTH; ptr += ED25519_PUBLIC_KEY_LENGTH;
if (!export_format && !_olm_crypto_ed25519_verify( if (!export_format) {
&session->signing_key, key_buf, ptr - key_buf, ptr if (!_olm_crypto_ed25519_verify(&session->signing_key, key_buf,
)) { ptr - key_buf, ptr)) {
session->last_error = OLM_BAD_SIGNATURE; session->last_error = OLM_BAD_SIGNATURE;
return (size_t)-1; return (size_t)-1;
}
/* signed keyshare */
session->signing_key_verified = 1;
} }
return 0; return 0;
} }
@ -174,6 +189,7 @@ static size_t raw_pickle_length(
length += megolm_pickle_length(&session->initial_ratchet); length += megolm_pickle_length(&session->initial_ratchet);
length += megolm_pickle_length(&session->latest_ratchet); length += megolm_pickle_length(&session->latest_ratchet);
length += _olm_pickle_ed25519_public_key_length(&session->signing_key); length += _olm_pickle_ed25519_public_key_length(&session->signing_key);
length += _olm_pickle_bool_length(session->signing_key_verified);
return length; return length;
} }
@ -201,6 +217,7 @@ size_t olm_pickle_inbound_group_session(
pos = megolm_pickle(&session->initial_ratchet, pos); pos = megolm_pickle(&session->initial_ratchet, pos);
pos = megolm_pickle(&session->latest_ratchet, pos); pos = megolm_pickle(&session->latest_ratchet, pos);
pos = _olm_pickle_ed25519_public_key(pos, &session->signing_key); 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); return _olm_enc_output(key, key_length, pickled, raw_length);
} }
@ -224,7 +241,7 @@ size_t olm_unpickle_inbound_group_session(
pos = pickled; pos = pickled;
end = pos + raw_length; end = pos + raw_length;
pos = _olm_unpickle_uint32(pos, end, &pickle_version); 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; session->last_error = OLM_UNKNOWN_PICKLE_VERSION;
return (size_t)-1; return (size_t)-1;
} }
@ -232,6 +249,14 @@ size_t olm_unpickle_inbound_group_session(
pos = megolm_unpickle(&session->latest_ratchet, pos, end); pos = megolm_unpickle(&session->latest_ratchet, pos, end);
pos = _olm_unpickle_ed25519_public_key(pos, end, &session->signing_key); 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) { if (end != pos) {
/* We had the wrong number of bytes in the input. */ /* We had the wrong number of bytes in the input. */
session->last_error = OLM_CORRUPTED_PICKLE; session->last_error = OLM_CORRUPTED_PICKLE;
@ -391,6 +416,10 @@ static size_t _decrypt(
return r; 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; return r;
} }