Commit graph

132 commits

Author SHA1 Message Date
Richard van der Hoff
c04b770cd3 Add some tests for inbound session import/export 2017-01-10 14:11:42 +00:00
Richard van der Hoff
fc72c732fd Store a flag indicating if the sender key is verified 2017-01-10 10:57:14 +00:00
Richard van der Hoff
a2f0c93a93 Implement importing group session data
olm_import_inbound_group_session, which reads the format written by
olm_export_inbound_group_session to initialise a group session.
2017-01-09 17:45:46 +00:00
Richard van der Hoff
5fbeb3e29b Enable exporting inbound group session keys
A pair of functions which allow you to export the megolm keys for an inbound
group session, so that an application can save/restore them.
2017-01-06 16:41:56 +00:00
Richard van der Hoff
a7310c5821 Return the base64-encoded length of pickles
make olm_pickle_* return the lengths of the base64-encoded pickles, rather than
the raw pickle. (From the application's POV, the format of the pickle is
opaque: it doesn't even know that it is base64-encoded. So returning the length
of the raw pickle is particularly unhelpful.)
2016-10-24 10:06:06 +01:00
Richard van der Hoff
21ce3491dd Clear random buf in olm_init_outbound_group_session
All the other methods clear their random inputs. This one needs to do the same,
to reduce the risk of the randomness being used elsewhere and leaking key info.
2016-10-21 17:19:59 +01:00
Mark Haines
5a98012c0d Merge pull request #31 from matrix-org/markjh/groupmessageindex
Return the message index when decrypting group messages.
2016-10-21 09:57:42 +01:00
Mark Haines
3091dc2b1d Add NULL check for message_index pointer 2016-10-20 11:35:45 +01:00
Mark Haines
653790eacb Return the message index when decrypting group messages.
Applications can use the index to detect replays of the same message.
2016-10-20 09:58:55 +01:00
Richard van der Hoff
1ff64391ed Fix a buffer bounds check when decoding group messages
Fixes a segfault when a group message had exactly the length of the mac +
signature.

Also tweak skipping of unknown tags to avoid an extra trip around the loop.
2016-10-19 15:03:40 +01:00
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
a89a169c89 `if is not the same as for` 2016-09-13 17:00:54 +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
833ecd3c73 Convert ed25519 pickling functions to C
... so that I can use them from the group session bits.
2016-09-05 12:59:12 +01:00
Richard van der Hoff
69f269ffaf Convert AES functions to plain C 2016-09-05 10:40:39 +01:00
Richard van der Hoff
f0acf6582f Convert Ed25519 and Curve25519 functions to plain C 2016-09-05 10:40:39 +01:00
Richard van der Hoff
2aad4cfa86 Merge pull request #15 from matrix-org/rav/has_received_message
OlmSession.has_received_message
2016-09-05 10:38:41 +01:00
Richard van der Hoff
2e9021c2e7 OlmSession.has_received_message
I find myself wanting to know if an OlmSession is in the pre-key state or not,
to help debugging at the application level.
2016-09-04 23:41:10 +01:00
Richard van der Hoff
39212987bd Create new constants for key lengths, etc
We were using olm::KEY_LENGTH for everything under the sun which happened to be
32 bytes long, and making a bunch of assumptions in the process. Create a bunch
of new constants (as C #defines rather than C++ consts so that I can use them
in another forthcoming refactor).
2016-09-02 15:11:14 +01:00
Richard van der Hoff
0c462cff11 Fix Ed25519 keypair generation
Ed25519 private keys, it turns out, have 64 bytes, not 32.

We were previously generating only 32 bytes (which is all that is required to
generate the public key), and then using the public key as the upper 32 bytes
when generating the per-message session key. This meant that everything
appeared to work, but the security of the private key was severely compromised.

By way of fixes:

 * Use the correct algorithm for generating the Ed25519 private key, and store
   all 512 bits of it.

 * Update the account pickle format and refuse to load the old format (since we
   should consider it compromised).

 * Bump the library version, and add a function to retrieve the library
   version, so that applications can verify that they are linked against a
   fixed version of the library.

 * Remove the curve25519_{sign, verify} functions which were unused and of
   dubious quality.
2016-09-01 13:35:23 +01:00
Richard van der Hoff
d8b24acb77 PR feedback
* write V1 pickles on the master branch
* the logging branch is going to write v0x80000001
2016-06-30 14:01:02 +01:00
Richard van der Hoff
8dd3c182ee Make space in the session pickle for chain index
Keeping track of the chain index is a useful thing to do, but is only required
if we've enabled diagnostics. Extend the session pickle format to make a space
for it, so that pickles can be transferred between the logging_enabled branch
and the master branch without loss of information.

Also add some tests for session pickling which explicitly check that we can
unpickle both formats of pickle.
2016-06-30 11:38:01 +01:00
Richard van der Hoff
757c422578 Remove unused 'chain_index' from Ratchet
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.
2016-06-30 11:31:36 +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
ee8172d882 Compile some of the crypto libs directly
sha256.c and aes.c contain conflicting declarations, so we need to compile them
as separate units. This requires a bit more Makefile-shuffling; the build
directory now includes 'src' or 'lib' as appropriate, and we just mkdir -p
before each compilation.
2016-05-25 17:08:44 +01:00
Richard van der Hoff
27b57c8d88 Merge branch 'rav/more_group_chat/1' 2016-05-25 15:46:50 +01:00
Richard van der Hoff
fae8dacab5 Add a comment explaining Mark's latest fix 2016-05-25 15:44:39 +01:00
Mark Haines
19a7fb5df5 Fix an integer wrap around bug and add a couple more tests 2016-05-25 15:00:05 +01:00
Richard van der Hoff
01ea3d4b9a Fix handling of integer wraparound in megolm.c 2016-05-24 17:52:35 +01:00
Richard van der Hoff
1f31427139 megolm_advance_to: Remove excessive optimisation
There was some slightly overcomplex logic designed to save a couple of hash
operations when R(0) and R(1) were advanced, but the extra code was hard to
understand and didn't save much.
2016-05-24 17:38:43 +01:00
Richard van der Hoff
ef8d24f483 megolm.c: rewrite counter update
We no longer need to keep track of intermediate values of the counter, which
means we can update it much more easily.
2016-05-24 17:33:41 +01:00
Richard van der Hoff
f3c0dd76d7 megolm.c: Remove spurious arguments to rehash_part
These were left over from when rehash_part did a bunch of logging.
2016-05-24 17:03:42 +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
15cb4ec0c0 Build the crypto libs as C99
Some of the crypto libs rely on UINT64_C, which in glibc 2.17 and earlier was
not defined for C++ code (see
https://sourceware.org/bugzilla/show_bug.cgi?id=15366).
2016-05-24 14:41:49 +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
Richard van der Hoff
8b1514c0a6 Implement functions to get the state of outbound session
We need to be able to inspect an outbound session so that we can tell our peer
how to set up an inbound session.
2016-05-24 13:39:34 +01:00
Richard van der Hoff
c058554132 Implement pickling/unpickling for outbound group sessions 2016-05-24 13:39:34 +01:00
Richard van der Hoff
caaed796ad Implementation of an outbound group session 2016-05-24 13:39:34 +01:00
Richard van der Hoff
68d3c7bfa9 Implementation of the megolm ratchet 2016-05-24 13:39:34 +01:00
Richard van der Hoff
42a300fc62 Factor out pickle_encoding from olm.cpp
We don't need to have all of the top-level pickling functions in olm.cpp;
factor out the utilities to support it to pickle_encoding.cpp (and make sure
that they have plain-C bindings).
2016-05-24 13:39:32 +01:00
Richard van der Hoff
256bce10fc Factor out olm_error_to_string to a separate file
I want to be able to use this functionality from elsewhere, so factor it out to
its own file.
2016-05-24 13:35:28 +01:00