When a key is gossiped for the contact in a verified chat,
it is stored in the secondary verified key slot.
The messages are then encrypted to the secondary verified key
if they are also encrypted to the contact introducing this secondary key.
Chat-Group-Member-Added no longer updates the verified key.
Verified group recovery only relies on the secondary verified key.
When a message is received from a contact
signed with a secondary verified key,
secondary verified key replaces the primary verified key.
When verified key is changed for the contact
in response to receiving a message
signed with a secondary verified key,
"Setup changed" message is added
to the same chat where the message is received.
This message makes that partial messages do not change the group state.
A simple fix and a comprehensive test is added. This is a follow up to
the former #4841 which took a different approach.
This is another approach to provide group membership consistency for all members. Considerations:
- Classical MUA users usually don't intend to remove users from an email thread, so if they removed
a recipient then it was probably by accident.
- DC users could miss new member additions and then better to handle this in the same way as for
classical MUA messages. Moreover, if we remove a member implicitly, they will never know that and
continue to think they're still here.
But it shouldn't be a big problem if somebody missed a member removal, because they will likely
recreate the member list from the next received message. The problem occurs only if that "somebody"
managed to reply earlier. Really, it's a problem for big groups with high message rate, but let it
be for now.
Result::Err is reserved for local errors,
such as database failures.
Not found peerstate in the database is a protocol failure,
so just return Ok(false) in mark_peer_as_verified().
This allows to handle more errors with `?`.
Otherwise SELF contact in the beginning of the vector
and in to_ids may be repeated twice and not deduplicated.
dedup() only deduplicates consecutive elements.
We may not have a verified key for other members
because we lost a gossip message.
Still, if the message is signed with a verified key
of the sender, there is no reason to replace it with an error.
feat: Make broadcast lists create their own chat - UIs need to ask for
the name when creating broadcast lists now (see
https://github.com/deltachat/deltachat-android/pull/2653)
That's quite a minimal approach: Add a List-ID header to outgoing
broadcast lists, so that the receiving Delta Chat shows them as a
separate chat, as talked about with @r10s and @hpk42.
Done:
- [x] Fix an existing bug that the chat name isn't updated when the
broadcast/mailing list name changes (I already started this locally)
To be done in other PRs:
- [ ] Right now the receiving side shows "Mailing list" in the subtitle
of such a chat, it would be nicer if it showed "Broadcast list" (or
alternatively, rename "Broadcast list" to "Mailing list", too)
- [ ] The UIs should probably ask for a name before creating the
broadcast list, since it will actually be sent over the wire. (Android
PR: https://github.com/deltachat/deltachat-android/pull/2653)
Fixes https://github.com/deltachat/deltachat-core-rust/issues/4597
BREAKING CHANGE: This means that UIs need to ask for the name when creating a broadcast list, similar to https://github.com/deltachat/deltachat-android/pull/2653.
Before they were trashed. Note that for unencrypted ones DC works as expected creating the requested
group immediately because Chat-Group-Id is duplicated in the Message-Id header and Subject is
fetched.
Also add a test on downloading a message later. Although it doesn't reproduce #4700 for some reason,
it fails w/o the fix because before a message state was changing to `InSeen` after a full download
which doesn't look correct. The result of a full message download should be such as if it was fully
downloaded initially.
9bd7ab72 brings a possibility of group membership inconsistency to the original Hocuri's algo
described and implemented in e12e026b in sake of security so that nobody can add themselves to a
group by forging "InReplyTo" and other headers. This commit fixes the problem by removing group
members locally if we see a discrepancy with the "To" list in the received message as it is better
for privacy than adding absent members locally. But it shouldn't be a big problem if somebody missed
a member addition, because they will likely recreate the member list from the next received
message. The problem occurs only if that "somebody" managed to reply earlier. Really, it's a problem
for big groups with high message rate, but let it be for now.
Also:
- Query chat contacts from the db only once.
- Update chat contacts in the only transaction, otherwise we can just break the chat contact list
halfway.
- Allow classic MUA messages to remove group members if a parent message is missing. Currently it
doesn't matter because unrelated messages go to new ad-hoc groups, but let this logic be outside
of apply_group_changes(). Just in case if there will be a MUA preserving "Chat-Group-ID" header
f.e.
Such a message may be assigned to a wrong chat (e.g. undecipherable group msgs often get assigned to
the 1:1 chat with the sender). Add `DownloadState::Undecipherable` so that messages referencing
undecipherable ones don't go to that wrong chat too. Also do not reply to not fully downloaded
messages. Before `Message.error` was checked for that purpose, but a message can be error for many
reasons.
It can be not good for membership consistency if we missed a message adding a member, but improves
security because nobody can add themselves to a group from now on.
1:1 chat may be blocked while the contact is not
if 1:1 chat was created as a result of scanning
a verified group join QR code with the contact
as the inviter. In this case 1:1 chat is blocked to hide it
while the contact is unblocked.
- If we don't know the parent (=In-Reply-To) message, then completely recreate the group member list
(i.e. use the member list of the incoming message) (because we assume that we missed some messages
& have a wrong group state).
- If the message has a "Chat-Group-Member-Removed: member@example.com" header, then remove this
member.
- If the message has a "Chat-Group-Member-Added: member@example.com" header, then add this member.
That means:
- Remove checks for the presense of `ContactId::SELF` in the group. Thus all recipients of a message
take the same decision about group membership changes, no matter if they are in the group
currently. This fixes a situation when a recipient thinks it's not a member because it missed a
message about its addition before.
NOTE: But always recreate membership list if SELF has been added. The older versions of DC don't
always set "In-Reply-To" to the latest message they sent, but to the latest delivered message (so
it's a race), so we need this heuristic currently.
- Recreate the group member list if we don't know the parent (=In-Reply-To) message, even if the
sender isn't in the group as per our view, because we missed some messages and our view may be
stale.
If a message is unsigned or signed with an unknown key, `MimeMessage::was_encrypted()` returns
false. So, it mustn't be checked when deciding whether to look into
`MimeMessage::decoded_data`. Looking through git history one can see that it's just a wrong check
left in the code for historical reasons.
Other MUAs don't set add/remove headers, so the only way for them to re-add us to the group is to
add us to To/CC/wherever. Previously it worked only for other members that are still in the group so
that they properly handled our re-addition, but we didn't.
If the Inbox is fetched before the Sentbox (as done currently), messages from the Sentbox will
correctly mingle with the Inbox messages in the end. So, this commit changes message ordering only
if we already have processed outgoing messages, e.g. if we just sent them in the chat as described
in #4621. Otherwise new incoming messages are displayed somewhere in the middle of the chat which
doesn't look usable.
