Normally NULL is used when there is no fingerprint, but default value
for fingerprint columns is an empty string.
In this case, loading should not fail with an "invalid length" error,
but treat the fingerprint as missing.
Strict check was introduced in commit ca95f25639
Since try_decrypt does not check if the message has valid signatures
anymore, it may return empty signatures set, which means the message is
not a valid autocrypt message.
Since introduction of provider database, these certificate checks are
enabled for test servers anyway, but this setting prevents usage of
local servers with self-signed certificates.
It presents no security issue, because properly configured servers will
only serve passwords on HTTPS and distribute only HTTPS QR codes, but
makes testing easier when HTTPS is not easy to deploy.
If attacker can control the URL used, they can change the URL to another
HTTPS URL controlled by them and act as a proxy between the client and
original server anyway.
Adhoc groups for group messages that don't have Chat-Group-ID are already
created above in another create_or_lookup_adhoc_group.
At this point it could be that there is a valid Chat-Group-ID header,
but no group was created because removed_id was non-zero i.e. received
message removes some group member.
If group was not explicitly left, current code creates an adhoc group
instead of trashing late or reordered messages that remove group
members. Such groups have adhoc group IDs locally, but proper group
message-IDs. Attempts to reply to such groups or leave them creates
"split groups" for all other members of original group. The solution is
not to create adhoc groups in this case.
Permanent error 550 5.1.1 is no longer considered temporary.
Enhanced status code is checked now, so only 550 5.5.0 is an exception
for misconfigured Postfix servers.
Yandex error 554 5.7.1 was handled correctly, but only because it had
response code 554, while the comment talks about enhanced status code
5.7.1. The comments are corrected.
Failed messages are now marked as such with message::set_msg_failed.
Previously they were left in a pending state.
If info message cannot be added to the chat, the error is displayed with
error! instead of being logged with warn!.
Now MarkseenMsgOnImap sends MDN even if it can't mark the message as
seen on the server.
To prevent multiple MDNs from being sent, MarkseenMsgOnImap is postponed
until the message is detected in a folder from which it is not going to
be moved.
Mimeparser.was_encrypted() checks if the message is an Autocrypt encrypted
message. It already means the message has a valid signature.
This commit documents a few functions to make it clear that signatures
stored in Mimeparser must be valid and must always come from encrypted
messages.
Also one unwrap() is eliminated in encrypted_and_signed(). It is possible
to further simplify encrypted_and_signed() by skipping the was_encrypted()
check, because the function only returns true if there is a matching
signature, but it is helpful for debugging to distinguish between
non-Autocrypt messages and messages whose fingerprint does not match.
Parallel processing of messages results in bugs such as messages sent by
a new member being processed before the message that adds this member to
the chat, even when it has lower UID. In this case, messages are shown as
"[Unknown sender for this chat. See 'info' for more details.]", while
there is a message "Member ... added" right before, because writing the
information about new member to the database takes longer then reading
old index from the database.
With this change, API user does not need to look at the timestamp of
the next message to display the day marker, but can get the timestamp
directly from the marker. This way there is no database query and no
risk of error as a result of database being busy or message being deleted.
Alexander Krotov