After talking with r10s:
For spring cleaning, remove the largely-unused things that can be done a
bit.
Most private messengers (WhatsApp/Signal/...) do not have this feature,
and we do not want to become Matrix where every client has different,
partly-incompatible features.
I used some AI to draft a first version of this, and then reworked it.
This is one of multiple possibilities to fix
https://github.com/chatmail/core/issues/8041: For bots, the IncomingMsg
event is not emitted when the pre-message arrives, only when the
post-message arrives. Also, post-messages are downloaded immediately,
not after all the small messages are downloaded.
The `get_next_msgs()` API is deprecated. Instead, bots need to listen to
the IncomingMsg event in order to be notified about new events. Is this
acceptable for bots?
THE PROBLEM THAT WAS SOLVED BY THIS:
With pre-messages, it's hard for bots to wait for the message to be fully downloaded and then process it.
Up until now, bots used get_next_msgs() to query the unprocessed messages, then set last_msg_id after processing a message to that they won't process it again.
But this will now also return messages that were not fully downloaded.
ALTERNATIVES:
In the following, I will explain
the alternatives, and for why it's not so easy to just make the
`get_next_msgs()` API work. If it's not understandable, I'm happy to
elaborate more.
Core can't just completely ignore the pre-message for two reasons:
- If a post-message containing a Webxdc arrives later, and some webxdc updates arrive in the meantime, then these updates will be lost.
- The post-message doesn't contain the text (reasoning was to avoid duplicate text for people who didn't upgrade yet during the 2.43.0 rollout)
There are multiple solutions:
- Add the message as hidden in the database when the pre-message arrives.
- When the post-message arrives and we want to make it available for bots, we need to update the msg_id because of how the `get_next_msgs()` API works. This means that we need to update all webxdc updates that reference this msg_id.
- Alternatively, we could make webxdc's reference the rfc724_mid instead of the msg_id, so that we don't need stable msg_ids anymore
- Alternatively, we could deprecate `get_next_msgs()`, and ask bots to use plain events for message processing again. It's not that bad; worst case, the bot crashes and then forgets to react to some messages, but the user will just try again. And if some message makes the bot crash, then it might actually be good not to try and process it again.
- Store the pre-message text and `PostMsgMetadata` (or alternatively, the whole mime) in a new database table. Wait with processing it until the post-message arrives.
Additionally, the logic that small messages are downloaded before post-messages should be disabled for bots, in order to prevent reordering.
Follow-up to https://github.com/chatmail/core/pull/7994/, in order to
prevent clashes with other things that are called `Transport`, and in
order to make the struct name more greppable
Closes https://github.com/chatmail/core/issues/7980.
Unpublished transports are not advertised to contacts, and self-sent messages are not sent there, so that we don't cause extra messages to the corresponding inbox, but can still receive messages from contacts who don't know the new relay addresses yet.
- This adds `list_transports_ex()` and `set_transport_unpublished()` JsonRPC functions
- By default, transports are published, but when updating, all existing transports except for the primary one become unpublished in order not to break existing users that followed https://delta.chat/legacy-move
- It is not possible to unpublish the primary transport, and setting a transport as primary automatically sets it to published
An alternative would be to change the existing list_transports API rather than adding a new one list_transports_ex. But to be honest, I don't mind the _ex prefix that much, and I am wary about compatibility issues. But maybe it would be fine; see b08ba4bb8 for how this would look.
fix https://github.com/chatmail/core/issues/7766
Implementation notes:
- Descriptions are only sent with member additions, when the description
is changed, and when promoting a previously-unpromoted group, in order
not to waste bandwith.
- Descriptions are not loaded everytime a chat object is loaded, because
they are only needed for the profile. Instead, they are in their own
table, and can be loaded with their own JsonRPC call.
---------
Co-authored-by: iequidoo <117991069+iequidoo@users.noreply.github.com>
Also remove "you can now call 'configure'" from the REPL output, probably users of the REPL tool can
read the code documentation to know when 'configure' should be run.
Adds an api to get all ui config keys. There already is an option to get
all normal config keys (`"sys.config_keys"`), but before this pr there
was no way to get all `ui.*` config keys.
#### Why is this api needed?
For webxdc cleanup on desktop, which stores window position in a ui
config key (such as `ui.desktop.webxdcBounds.676464`) as soon as a
webxdc is opened since many versions now. So listing all ui keys is a
good way for us to find out which webxdc may have web data stored.
unfortunately electron does not (yet?) have a way to list all origins
that have web-data like android does, so this is the next best thing we
can do before itterating all possible ids, see also
https://github.com/deltachat/deltachat-desktop/issues/5758.
#### Why is this only a jsonrpc api and not another special/virtual
config key like `"sys.config_keys"`?
r10s indicated that `ui.*`-config keys are barely used
(https://github.com/deltachat/deltachat-desktop/issues/5790#issuecomment-3598512802),
so I thought it makes more sense to add it as dedicated api which's
existentence is checked by the typechecker, so it will be easier to not
miss it when we should remove the api again in the future.
But we could also do a dedicated special/virtual config key for it, if
you think that is better, this is easy to change.
---------
Co-authored-by: iequidoo <117991069+iequidoo@users.noreply.github.com>
Add `chat::forward_msgs_2ctx()` which takes another context as a parameter and forwards messages to
it and its jsonrpc wrapper `CommandApi::forward_messages_to_account()`.
This API allows to check if the message with
given ID exists and distinguish between
message not existing and database error.
It might also be faster than
checking messages one by one
if multiple messages need to be checked
because of using a single SQL transaction.
New APIs are JSON-RPC method stop_background_fetch(),
Rust method Accounts.stop_background_fetch()
and C method dc_accounts_stop_background_fetch().
These APIs allow to cancel background fetch early
even before the initially set timeout,
for example on Android when the system calls
`Service.onTimeout()` for a `dataSync` foreground service.
Follow-up for https://github.com/chatmail/core/pull/7042, part of
https://github.com/chatmail/core/issues/6884.
This will make it possible to create invite-QR codes for broadcast
channels, and make them symmetrically end-to-end encrypted.
- [x] Go through all the changes in #7042, and check which ones I still
need, and revert all other changes
- [x] Use the classical Securejoin protocol, rather than the new 2-step
protocol
- [x] Make the Rust tests pass
- [x] Make the Python tests pass
- [x] Fix TODOs in the code
- [x] Test it, and fix any bugs I find
- [x] I found a bug when exporting all profiles at once fails sometimes,
though this bug is unrelated to channels:
https://github.com/chatmail/core/issues/7281
- [x] Do a self-review (i.e. read all changes, and check if I see some
things that should be changed)
- [x] Have this PR reviewed and merged
- [ ] Open an issue for "TODO: There is a known bug in the securejoin
protocol"
- [ ] Create an issue that outlines how we can improve the Securejoin
protocol in the future (I don't have the time to do this right now, but
want to do it sometime in winter)
- [ ] Write a guide for UIs how to adapt to the changes (see
https://github.com/deltachat/deltachat-android/pull/3886)
## Backwards compatibility
This is not very backwards compatible:
- Trying to join a symmetrically-encrypted broadcast channel with an old
device will fail
- If you joined a symmetrically-encrypted broadcast channel with one
device, and use an old core on the other device, then the other device
will show a mostly empty chat (except for two device messages)
- If you created a broadcast channel in the past, then you will get an
error message when trying to send into the channel:
> The up to now "experimental channels feature" is about to become an officially supported one. By that, privacy will be improved, it will become faster, and less traffic will be consumed.
>
> As we do not guarantee feature-stability for such experiments, this means, that you will need to create the channel again.
>
> Here is what to do:
> • Create a new channel
> • Tap on the channel name
> • Tap on "QR Invite Code"
> • Have all recipients scan the QR code, or send them the link
>
> If you have any questions, please send an email to delta@merlinux.eu or ask at https://support.delta.chat/.
## The symmetric encryption
Symmetric encryption uses a shared secret. Currently, we use AES128 for
encryption everywhere in Delta Chat, so, this is what I'm using for
broadcast channels (though it wouldn't be hard to switch to AES256).
The secret shared between all members of a broadcast channel has 258
bits of entropy (see `fn create_broadcast_shared_secret` in the code).
Since the shared secrets have more entropy than the AES session keys,
it's not necessary to have a hard-to-compute string2key algorithm, so,
I'm using the string2key algorithm `salted`. This is fast enough that
Delta Chat can just try out all known shared secrets. [^1] In order to
prevent DOS attacks, Delta Chat will not attempt to decrypt with a
string2key algorithm other than `salted` [^2].
## The "Securejoin" protocol that adds members to the channel after they
scanned a QR code
This PR uses the classical securejoin protocol, the same that is also
used for group and 1:1 invitations.
The messages sent back and forth are called `vg-request`,
`vg-auth-required`, `vg-request-with-auth`, and `vg-member-added`. I
considered using the `vc-` prefix, because from a protocol-POV, the
distinction between `vc-` and `vg-` isn't important (as @link2xt pointed
out in an in-person discussion), but
1. it would be weird if groups used `vg-` while broadcasts and 1:1 chats
used `vc-`,
2. we don't have a `vc-member-added` message yet, so, this would mean
one more different kind of message
3. we anyways want to switch to a new securejoin protocol soon, which
will be a backwards incompatible change with a transition phase. When we
do this change, we can make everything `vc-`.
[^1]: In a symmetrically encrypted message, it's not visible which
secret was used to encrypt without trying out all secrets. If this does
turn out to be too slow in the future, then we can remember which secret
was used more recently, and and try the most recent secret first. If
this is still too slow, then we can assign a short, non-unique (~2
characters) id to every shared secret, and send it in cleartext. The
receiving Delta Chat will then only try out shared secrets with this id.
Of course, this would leak a little bit of metadata in cleartext, so, I
would like to avoid it.
[^2]: A DOS attacker could send a message with a lot of encrypted
session keys, all of which use a very hard-to-compute string2key
algorithm. Delta Chat would then try to decrypt all of the encrypted
session keys with all of the known shared secrets. In order to prevent
this, as I said, Delta Chat will not attempt to decrypt with a
string2key algorithm other than `salted`
BREAKING CHANGE: A new QR type AskJoinBroadcast; cloning a broadcast
channel is no longer possible; manually adding a member to a broadcast
channel is no longer possible (only by having them scan a QR code)
This way, the statistics / self-reporting bot will be made into an
opt-in regular sending of statistics, where you enable the setting once
and then they will be sent automatically. The statistics will be sent to
a bot, so that the user can see exactly which data is being sent, and
how often. The chat will be archived and muted by default, so that it
doesn't disturb the user.
The collected statistics will focus on the public-key-verification that
is performed while scanning a QR code. Later on, we can add more
statistics to collect.
**Context:**
_This is just to give a rough idea; I would need to write a lot more
than a few paragraphs in order to fully explain all the context here_.
End-to-end encrypted messengers are generally susceptible to MitM
attacks. In order to mitigate against this, messengers offer some way of
verifying the chat partner's public key. However, numerous studies found
that most popular messengers implement this public-key-verification in a
way that is not understood by users, and therefore ineffective - [a 2021
"State of Knowledge" paper
concludes:](https://dl.acm.org/doi/pdf/10.1145/3558482.3581773)
> Based on our evaluation, we have determined that all current E2EE
apps, particularly when operating in opportunistic E2EE mode, are
incapable of repelling active man-in-the-middle (MitM) attacks. In
addition, we find that none of the current E2EE apps provide better and
more usable [public key verification] ceremonies, resulting in insecure
E2EE communications against active MitM attacks.
This is why Delta Chat tries to go a different route: When the user
scans a QR code (regardless of whether the QR code creates a 1:1 chat,
invites to a group, or subscribes to a broadcast channel), a
public-key-verification is performed in the background, without the user
even having to know about this.
The statistics collected here are supposed to tell us whether Delta Chat
succeeds to nudge the users into using QR codes in a way that is secure
against MitM attacks.
**Plan for statistics-sending:**
- [x] Get this PR reviewed and merged (but don't make it available in
the UI yet; if Android wants to make a release in the meantime, I will
create a PR that removes the option there)
- [x] Set the interval to 1 week again (right now, it's 1 minute for
testing)
- [ ] Write something for people who are interested in what exactly we
count, and link to it (see `TODO[blog post]` in the code)
- [ ] Prepare a short survey for participants
- [ ] Fine-tune the texts at
https://github.com/deltachat/deltachat-android/pull/3794, and get it
reviewed and merged
- [ ] After the next release, ask people to enable the
statistics-sending
If we use modules (which are actually namespaces), we can use shorter names. Another approach is to
only use modules for internal code incapsulation and use full names like deltachat-ffi does.
Create unprotected group in test_create_protected_grp_multidev
The test is renamed accordingly.
SystemMessage::ChatE2ee is added in encrypted groups
regardless of whether they are protected or not.
Previously new encrypted unprotected groups
had no message saying that messages are end-to-end encrypted
at all.
MX record lookup was only used to detect Google Workspace domains.
They can still be configured manually.
We anyway do not want to encourage creating new profiles
with Google Workspace as we don't have Gmail OAUTH2 token anymore
and new users can more easily onboard with a chatmail relay.
Some Delta Chat clients (Desktop, for example)
do `leave_webxdc_realtime`
regardless of whether we've ever joined a realtime channel
in the first place. Such as when closing a WebXDC window.
This might result in unexpected and suspicious firewall warnings.
Co-authored-by: iequidoo <dgreshilov@gmail.com>
Follow-up to https://github.com/chatmail/core/pull/7125: We now have a
mix of non-async (parking_lot) and async (tokio) Mutexes used for the
connectivity. We can just use non-async Mutexes, because we don't
attempt to hold them over an await point. I also tested that we get a
compiler error if we do try to hold one over an await point (rather than
just deadlocking/blocking the executor on runtime).
Not 100% sure about using the parking_lot rather than std Mutex, because
since https://github.com/rust-lang/rust/issues/93740, parking_lot
doesn't have a lot of advantages anymore. But as long as iroh depends on
it, we might as well use it ourselves.
New public API `set_accounts_order` allows setting the order of accounts.
The account order is stored as a list of account IDs in `accounts.toml`
under a new `accounts_order: Vec<u32>` field.
Part of #6884
----
- [x] Add new chat type `InBroadcastChannel` and `OutBroadcastChannel`
for incoming / outgoing channels, where the former is similar to a
`Mailinglist` and the latter is similar to a `Broadcast` (which is
removed)
- Consideration for naming: `InChannel`/`OutChannel` (without
"broadcast") would be shorter, but less greppable because we already
have a lot of occurences of `channel` in the code. Consistently calling
them `BcChannel`/`bc_channel` in the code would be both short and
greppable, but a bit arcane when reading it at first. Opinions are
welcome; if I hear none, I'll keep with `BroadcastChannel`.
- [x] api: Add create_broadcast_channel(), deprecate
create_broadcast_list() (or `create_channel()` / `create_bc_channel()`
if we decide to switch)
- Adjust code comments to match the new behavior.
- [x] Ask Desktop developers what they use `is_broadcast` field for, and
whether it should be true for both outgoing & incoming channels (or look
it up myself)
- I added `is_out_broadcast_channel`, and deprecated `is_broadcast`, for
now
- [x] When the user changes the broadcast channel name, immediately show
this change on receiving devices
- [x] Allow to change brodacast channel avatar, and immediately apply it
on the receiving device
- [x] Make it possible to block InBroadcastChannel
- [x] Make it possible to set the avatar of an OutgoingChannel, and
apply it on the receiving side
- [x] DECIDE whether we still want to use the broadcast icon as the
default icon or whether we want to use the letter-in-a-circle
- We decided to use the letter-in-a-circle for now, because it's easier
to implement, and I need to stay in the time plan
- [x] chat.rs: Return an error if the user tries to modify a
`InBroadcastChannel`
- [x] Add automated regression tests
- [x] Grep for `broadcast` and see whether there is any other work I
need to do
- [x] Bug: Don't show `~` in front of the sender's same in broadcast
lists
----
Note that I removed the following guard:
```rust
if !new_chat_contacts.contains(&ContactId::SELF) {
warn!(
context,
"Received group avatar update for group chat {} we are not a member of.", chat.id
);
} else if !new_chat_contacts.contains(&from_id) {
warn!(
context,
"Contact {from_id} attempts to modify group chat {} avatar without being a member.",
chat.id,
);
} else [...]
```
i.e. with this change, non-members will be able to modify the avatar.
Things were slightly easier this way, and I think that this is in line
with non-members being able to modify the group name and memberlist
(they need to know the Group-Chat-Id, anyway), but I can also change it
back.
This change introduces a new type of contacts
identified by their public key fingerprint
rather than an e-mail address.
Encrypted chats now stay encrypted
and unencrypted chats stay unencrypted.
For example, 1:1 chats with key-contacts
are encrypted and 1:1 chats with address-contacts
are unencrypted.
Groups that have a group ID are encrypted
and can only contain key-contacts
while groups that don't have a group ID ("adhoc groups")
are unencrypted and can only contain address-contacts.
JSON-RPC API `reset_contact_encryption` is removed.
Python API `Contact.reset_encryption` is removed.
"Group tracking plugin" in legacy Python API was removed because it
relied on parsing email addresses from system messages with regexps.
Co-authored-by: Hocuri <hocuri@gmx.de>
Co-authored-by: iequidoo <dgreshilov@gmail.com>
Co-authored-by: B. Petersen <r10s@b44t.com>
