RequireCRAM (another fairly stupid "use if available" option) is now
deprecated. instead, the AuthMech option can be used to give a precise
list of acceptable authentication mechanisms (which is currently "a bit"
short). in particular, this allows *not* using CRAM-MD5 even if it's
available.
the combinations of the various options made quite a mess. additionally,
'RequireSSL no' is inherently insecure - "use SSL if available" is plain
stupid.
the old options are still accepted, but will elicit a warning.
such connections don't support STARTTLS. that is reasonable, as whatever
makes the connection preauthenticated (typically a Tunnel used to launch
imapd via a shell login) must already rely on the connection's security.
consequently, we would not try to use STARTTLS with such connections.
unfortunately, we'd also skip the RequireSSL check as a side effect.
this means that a rogue server (via a MITM attack) could simply offer a
preauthenticated connection to make us not use SSL, and thus bypass
server authentication. as a result, we could send potentially sensitive
data to the attacker:
- with Patterns used, we would send a LIST command which reveals the
remote Path setting. this isn't very useful to an attacker. also, IMAP
Accounts usually rely on the server-provided NAMESPACE to start with.
- with Create enabled for the remote Store, we would upload messages
from newly appeared local folders. this isn't a very likely situation,
unless the attacker manages to convince the victim to move/copy
interesting mails to a new folder right before the attack.
- with Expunge enabled for the local Store, previously synchronized
folders would be wiped. however, this would require the attacker to
know the correct UIDVALIDITY of each remote folder, which would
require incredible luck or convincing the victim to disclose them.
the first mismatch would likely tip off the victim.
in practice, someone with the level of technical and social engineering
skills required for this attack would very likely find more attractive
attack vectors. therefore, i don't consider this a particularly serious
issue.
configurations with UseIMAPS enabled or using a secure Tunnel were not
affected to start with.
a side effect of this fix is that most users of Tunnel will now need to
explicitly set RequireSSL to false.
an alternative approach would be defaulting all SSL-related settings to
off when Tunnel is used. this would be too invasive for a patch release,
but i'll consider it for 1.2.
see also CVE-2014-2567 for the Trojita MUA.
unlike the isync wrapper, mbsync does not have a default for the IMAP
user. the remote user seldomly matches the local one, so "forwarding" it
is more confusing than helpful.
CCMAIL: 744389@bugs.debian.org
as the named boxes are the same on both sides, they logically make
sense only when the channel is in that mode anyway, which is the case
when using patterns.
sneaky change on the side: the wording of the man page is changed from
"outside any section" to "before any section" to get global options.
this is not entirely true ... the previously existing options behave as
before, while the two newcomers actually affect subsequent channels.
the test suite actually relies on it. it would be possible to adjust it,
but there is not much reason to make paths relative to HOME (as we
support convenient tilde expansion). so use the least invasive approach,
which is simply the old behavior. adjust the documentation accordingly.
This reverts commit da5ce5d8f4.
leave all the hard work to OpenSSL. this has several consequences:
- certificate chain validation actually works instead of throwing
around error 20
- the interactive approval is gone. i don't expect it to be useful
anyway, as mbsync is mostly a batch tool
- the code is much shorter
in fact, UIDNEXT (and UIDVALIDITY) null is *not* allowed (see RFC3501
section 9). them popping up nonetheless was a dovecot bug (which would
also confuse dovecot itself).
having it in as a workaround was no good either, as quite some other
code in mbsync assumes that UIDs are not null.
This reverts commit e1fa867 and most of 39006d7.
-REFMAIL: 4CA62BA1.4020104@lemma.co.uk
- asynchronous sockets using an event loop
- connect & starttls have completion callback parameters
- callbacks for notification about filled input buffer and emptied
output buffer
- unsent imap command queue
- used when
- socket output buffer is non-empty
- number of commands in flight exceeds limit
- last sent command requires round-trip
- command has a dependency on completion of previous command
- trashnc is tri-state so only a single "scout" trash APPEND/COPY is
sent at first. a possibly resulting CREATE is injected in front of
the remaining trash commands, so they can succeed (or be cancel()d
if it fails).
- queue's presence necessitates imap_cancel implementation
as opposed to earlier threats, BerkDB was not entirely dropped; i
suppose the isync 0.7 -> 0.8 change had a reason, so i added an
alternative UID storage scheme.
note that BDB 4.0 is not sufficient, as the db->open function changed in
an incompatible way ...
i updated the debian packaging except for a changelog entry.
note that i removed the upgrade blurb, as upstream now has a smooth
upgrade path down to at least isync 0.4.
