some servers actually bother to close down the SSL connection before
closing the socket.
this fixes the spurious "unhandled SSL error 6" messages.
REFMAIL: 20150120114805.GA17586@leeloo.kyriasis.com
the server can actually close the zlib stream before closing the socket,
so we need to accept it.
we don't do anything beyond that - the actual EOF will be signaled by
the socket, and if the server (erroneously) sends more data, zlib will
tell us about it.
REFMAIL: 1423048708-975-1-git-send-email-alex.bennee@linaro.org
zlib reports Z_BUF_ERROR when a flush is attempted without any activity
since the previous flush (if any). while this is harmless as such,
discerning the condition from genuine errors would be much harder than
avoiding the pointless flush in the first place.
REFMAIL: eb5681612f17be777bc8d138d31dd6d6@mpcjanssen.nl
don't retry dead Stores for every Channel.
this also introduces a state for transient errors (specifically, connect
failures), but this is currently unused.
a directory is no mailbox unless it contains a cur/ subdir.
but if that one is present, create new/ and tmp/ if they are missing.
this makes it possible to resume interrupted maildir creations.
don't try to lock it until we actually read or write it.
the idea is to not fail with SyncState * if we tried to load the state
before selecting a non-existing mailbox. this is ok, because if the
mailbox is missing, we obviously have no sync state pertaining to it,
either.
as a side effect, this allows simplifying an error path.
when LITERAL+ is used, the server has no chance for early rejection of
messages. this means that the client can upload megabytes for nothing.
so simply don't use LITERAL+ for big messages. of course this adds
server roundtrips, but that's tough luck.
the limit could be arguably higher than 100k (or even configurable).
i set it to ~2 sec with my fairly average DSL line.
the primary objective is reducing the number of small SSL packets (which
are always padded), but fewer syscalls in the non-SSL case should be
good as well.
instead of keeping the structures in an opaque array (which was a shadow
of the struct pollfd array if poll() was supported), make them directly
addressable.
this has the advantage that notifier-altering operations (mostly
en-/disabling) don't need to look up the structure by file handle each
time.
on the downside, data locality in the main loop is worse.
neither of these have any real effect on performance.
note that the structures are not allocated separately, but embedded into
the the parent structure (like sockets already were).
the seznam.cz IMAP server seems very eager to send UIDNEXT responses
despite not supporting UIDPLUS. this doesn't appear to be a particularly
sensible combination, but it's valid nonetheless.
however, that means that we need to save the UIDNEXT value before we
start storing messages, lest imap_find_new_msgs() will simply overlook
them. we do that outside the driver, in an already present field - this
actually makes the main path more consistent with the journal recovery
path.
analysis by Tomas Tintera <trosos@seznam.cz>.
REFMAIL: 20141220215032.GA10115@kyvadlo.trosos.seznam.cz
we can't leave the store FRESH, as otherwise the error handling code
will assume it is still being opened and will return to the main loop.
depending on the config this would cause an immediate termination or an
indefinite wait.
this re-introduces 6741bc94 (just a bit differently), thus effectively
reverting fbfcfea5. i suppose this extra CRLF is needed by a broken
CRAM-MD5 implementation of some server, which is why it was there in the
original implementation as well. however, it breaks more pedantic
non-broken servers. if somebody complains, we'll need to add a much
more sophisticated hack.
we should make no assumptions about the layout of OpenSSL's certificate
store, in particular when they are wrong. so copy the interesting part
instead of "deep-linking" into it.
this code is uglier than it should be, but OpenSSL's extensive use of
macros to manage data types would force us to include the ssl headers
into our headers otherwise, which would be even uglier.
REFMAIL: <545442CC.9020400@nodivisions.com>
... for windows fs compatibility.
the maildir-specific InfoDelimiter inherits the global FieldDelimiter
(which affects SyncState), based on the assumption that if the sync
state is on a windows FS, the mailboxes certainly will be as well, while
the inverse is not necessarily true (when running on unix, anyway).
REFMAIL: <CA+m_8J1ynqAjHRJagvKt9sb31yz047Q7NH-ODRmHOKyfru8vtA@mail.gmail.com>
patch initially by Jack Stone <jwjstone@fastmail.fm>,
cleaned up by Jan Synacek <jsynacek@redhat.com>,
... and then almost completely rewritten by me. ^^
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.
instead of using a callback which messes with the certificate chain
verification, simply let OpenSSL ignore errors during that phase and
check the result only afterwards.
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.
it doesn't belong there - it's a property of imap_server_conf_t.
the port setup is now done while reading the config.
this makes socket.[hc] imap-agnostic.
memcmp() is unfortunately not guaranteed to read forward byte-by-byte,
which means that the clever use as a strncmp() without the pointless
strlen()s is not permitted, and can actually misbehave with
SSE-optimized string functions.
so implement proper equals() and starts_with() functions. as a bonus,
the calls are less cryptic.
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.
the highest assigned UID must always be at least as high as the highest
actually found UID, as otherwise we'd hand out duplicate UIDs at some
point. also, getting into such a state in the first place indicates some
potentially serious trouble, or at least external interference (e.g.,
moving/copying a message from another folder without giving it a
pristine filename).
REFMAIL: 20140626211831.GA11590@sie.protva.ru
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
a failure here is rather unlikely, but let's be pedantic.
a failure is not fatal (we'll just enter the journal replay path next
time), so only print warnings.
found by coverity.
the code was copied and the original adjusted ... but not quite
completely.
this means that clashing server names never really worked since - not
that i would have expected this to be a particularly common
configuration to start with. :D
also added comments explaining why there are two implementations of the
same thing.
amends aea4be19e3 (anno 2006).
found by coverity.
we would try to print the uids from the non-existing srec of unpaired
messages while preparing expiration.
this would happen only if a) MaxMessages was configured and b) new
messages appeared on the slave but we were not pushing, so it's a bit of
a corner case.
found by coverity.
this would happen in the absurd corner case that the response code is
properly terminated with a closing bracket, but the atom itself is an
unterminated double-quoted string.
NOT found by coverity.
if something managed to make the maildir .uidvalidity files big enough
(possible only by appending garbage or scrambling them alltogether), we
would overflow the read buffer by one when appending the terminating
null.
this is not expected to have any real-world impact.
found by coverity.
for some reason lost in history, the prime_deltas were actually wrong,
leading to using composite numbers.
the right sequence is available at http://oeis.org/A092131.
the trivial approach of having "home" and "root" stores produced ugly
results, and totally failed with the introduction of nested folder
handling.
instead, create a store per local directory, just as one would manually.
CCMAIL: 737708@bugs.debian.org
makes for leaner Channel sections.
note: the global delete and expunge variables exist so the command line
can override the config file despite the otherwise backwards behavior.
