Commit graph

14 commits

Author SHA1 Message Date
Mark Haines
d7bc00c81d Merge pull request #23 from matrix-org/markjh/remove_message_index
Remove the messsage index from olm_init_inbound_group_session
2016-09-13 17:54:14 +01:00
Mark Haines
a628ef41bd Remove the messsage index from olm_init_inbound_group_session since it is read from the session_key 2016-09-13 17:51:02 +01:00
Mark Haines
6971f54fea Add a olm_inbound_group_session_id method 2016-09-13 17:02:36 +01:00
Mark Haines
5926a8fd29 Comment on the encoding of the message counter. 2016-09-13 16:45:54 +01:00
Mark Haines
d62e344db7 Use the ed22519 public key as the group session id.
Some clients expect the session id to be globally unique,
so allowing the end devices to pick the session id will cause
problems.

Include the current ratchet index with the initial keys, this decreases
the risk that the client will supply the wrong index causing problems.

Sign the initial keys with the ratchet ed25519 key, this reduces the
risk of a client claiming a session that they didn't create.
2016-09-13 15:42:47 +01:00
Richard van der Hoff
2fc83aa9ac Sign megolm messages
Add ed25519 keys to the inbound and outbound sessions, and use them to sign and
verify megolm messages.

We just stuff the ed25519 public key in alongside the megolm session key (and
add a version byte), to save adding more boilerplate to the JS/python/etc
layers.
2016-09-06 15:26:26 +01:00
Richard van der Hoff
708fddd747 Remove session_id from group messages
Putting the session_id inside the packed message body makes it hard to extract
so that we can decide which session to use. We don't think there is any
advantage to having thes sesion_id protected by the HMACs, so we're going to
move it to the JSON framing.
2016-05-25 17:42:32 +01:00
Richard van der Hoff
1b15465c42 Separate base64ing from the rest of msg encoding
Factor the actual message encoding/decoding and encrypting/decrypting out to
separate functions from the top-level functions which do the base64-wrangling.

This is particularly helpful in the 'outbound' code-path where the offsets
required to allow room to base64-encode make the flow hard to see when it's all inline.
2016-05-24 16:23:19 +01:00
Richard van der Hoff
a919a149fb Update megolm_cipher as a global struct
Initialise megolm_cipher via the preprocessor macro, instead of with a
function.
2016-05-24 14:54:01 +01:00
Richard van der Hoff
fa1e9446ac Use _olm_unset instead of memset
memset is at risk of being optimised away, so use _olm_unset instead.
2016-05-24 13:40:21 +01:00
Richard van der Hoff
173cbe112c Avoid relying on uint -> int casting behaviour
The behaviour when casting from a uint32_t which has overflowed (so has the top
bit set) to int32_t is implementation-defined, so let's avoid relying on it.
2016-05-24 13:40:21 +01:00
Richard van der Hoff
fc4756ddf1 Fix up some names, and protobuf tags
Make names (of session_key and message_index) more consistent.

Use our own protobuf tags rather than trying to piggyback on the one-to-one
structure.
2016-05-24 13:40:21 +01:00
Richard van der Hoff
a073d12d83 Support for pickling inbound group sessions 2016-05-24 13:40:21 +01:00
Richard van der Hoff
39ad75314b Implement decrypting inbound group messages
Includes creation of inbound sessions, etc
2016-05-24 13:39:34 +01:00