Commit Graph

1231 Commits

Author SHA1 Message Date
Oswald Buddenhagen
ba13362a52 deal with oversized messages in maildirs
don't try to read messages > 2G, as that will only lead to trouble down
the line.

this wouldn't have worked on linux anyway (we read in one chunk, and
that is limited to (2^31 - 2^12) on all architectures), but on
platforms were big reads work, this was a security problem if one
synchronized other users' maildirs.

as a minor fix on the side, we now also clip the reported message size,
so MaxSize works for excessively big messages.
2021-12-01 10:07:40 +01:00
Oswald Buddenhagen
463272eab8 CVE-2021-3657: reject excessively large IMAP literals
we didn't limit the 32-bit size of literals so far, which, given that we
use int-sized lengths & offsets, permitted all kinds of buffer
overflows. malicious/compromised servers may have been able to exploit
this. actual email senders would be constrained by size limits for
delivered mails, and to cause more than a crash they'd have to predict
the exact size of the final message.

we now limit to 2GB, which, given that we use unsigned ints since
e2d3b4d55 (v1.4.0), gives the handlers downstream plenty of headroom.

an alternative would have been using 64-bit offsets, but this seems like
major overkill, even if IMAP4rev2 recently mandated it (we talk only
IMAP4rev1, so we can ignore it).
2021-12-01 10:07:24 +01:00
Oswald Buddenhagen
87065c12b4 CVE-2021-44143: don't overflow heap on messages without headers
when a broken/compromised/malicious server gives us a message that
starts with an empty line, we'd enter the path for inserting a pristine
placeholder subject, for which we unfortunately didn't actually allocate
space (unless MaxSize is in use and the message exceeds it).

note that this cannot be triggered by merely receiving a crafted mail
with no headers (yes, it's actually possible to send such a thing), as
the delivery of mails adds plenty of headers.

amends 70bad661.
2021-11-25 16:14:32 +01:00
Oswald Buddenhagen
6e5dc6c2f2 bump version 2021-07-29 13:14:24 +02:00
Oswald Buddenhagen
7979782676 limit maildir nesting depth
this is a cheap way to catch symlink loops. 10 seems like a reasonable
limit, as it's unlikely that anyone would be able to actually work with
such a deeply nested mailbox tree.

fixes debian bug #990117.
2021-07-29 13:14:18 +02:00
Oswald Buddenhagen
a846ab054d enable embedding arbitrarily long strings into IMAP commands
the AUTHENTICATE command may get insanely long for GSSAPI when SASL-IR
is available. instead of growing the buffers each time someone hits the
limit (as done in f7cec306), remove the limitation altogether.

imap_vprintf() still contains a fixed-size buffer which could overflow
when really long strings (e.g., mailbox names) need to be quoted. this
seems very unlikely, so we'll deal with it if someone actually hits it.

REFMAIL: 87sg1qxdye.fsf@cern.ch
2021-06-11 18:24:00 +02:00
Oswald Buddenhagen
da65672f08 bump version 2021-06-03 11:07:35 +02:00
Oswald Buddenhagen
444601a1e0 Merge branch '1.3' into 1.4
Conflicts:
	configure.ac
	src/drv_imap.c
2021-06-03 11:04:56 +02:00
Oswald Buddenhagen
ed3bfdac4a bump version 2021-06-03 11:02:40 +02:00
Oswald Buddenhagen
589d2ed428 CVE-2021-3578: fix handling of unexpected APPENDUID response code
if the code was sent in response to anything but a STORE, we'd overwrite
a data pointer in one of our imap_cmd subclasses, an allocator data
structure, or the start of the next allocation, with an int that was
completely under the server's control. it's plausible that this could be
exploited for remote code execution.

to avoid this, we could ensure that the object is of the right type
prior to casting, by using a new flag in the parameter block. but it's
easier to just dispose of the out_uid field altogether and reuse the uid
field that is present in the parameter block anyway, but was used only
for FETCH commands so far.

this problem was found by Lukas Braun <koomi@moshbit.net> using a
fuzzer.
2021-06-03 11:02:23 +02:00
Oswald Buddenhagen
a86e6f8c7c don't crash on malformed CAPABILITY responses
amends 95a83c822.

this problem was found by Lukas Braun <koomi@moshbit.net> using a
fuzzer.
2021-06-02 15:51:23 +02:00
Oswald Buddenhagen
d8feb67dae tolerate INBOX mis-casing in Path
while it's technically reasonable to expect the user to match the
server's casing of INBOX if they set Path, this might come as a
surprise to those who know that the IMAP INBOX is case-insensitive.
so tolerate any casing instead. as a minor side effect, we'd now even be
able to deal with a server using different casing in NAMESPACE and LIST.
2021-03-19 18:21:34 +01:00
Oswald Buddenhagen
4b185e35fe Merge branch '1.3' into 1.4
Conflicts:
	configure.ac
	src/drv_imap.c
2021-02-21 21:26:54 +01:00
Oswald Buddenhagen
d55ced04ed bump version 2021-02-21 21:24:48 +01:00
Oswald Buddenhagen
594e60bd74 make UIDVALIDITY recovery more strict about vanished messages
in particular, this covers the case of a mailbox being replaced with an
empty new one, which would subsequently lead to the opposite end being
emptied as well, which would typically be undesired.

also add plenty of comments.
2021-02-21 21:11:58 +01:00
Oswald Buddenhagen
6796e041ae improve error messages about irrecoverably changed UIDVALIDITY
don't print the actual values, which are meaningless technicalities
to the average user, and can be obtained separately for debugging if
really necessary.
also, fix the omission of the affected mailboxes from one of the
messages.
2021-02-21 21:11:58 +01:00
Oswald Buddenhagen
fe5d59f8e3 CVE-2021-20247: reject funny mailbox names from IMAP LIST/LSUB
in particular, '..' in the name could be used to escape the Path/Inbox
of a Maildir Store, which could be exploited for stealing or deleting
data, or staging a (mild) DoS attack.
2021-02-21 20:40:22 +01:00
Oswald Buddenhagen
95a83c8220 be more tolerant of formally malformed response codes
fastmail sends flags containing ']' in PERMANENTFLAGS, which is formally
illegal. however, if we parse the embedded list before looking for the
response code's closing ']', things work out fine.

as a side effect we won't complain about similarly or completely
malformed response codes we don't recognize at all, which may or may not
be considered an improvement ...
2021-02-14 23:47:14 +01:00
Oswald Buddenhagen
8c86f34bf0 fix bogus continuation of IMAP list parsing
on error, parse_imap_list() needs to reset the nesting level in the
state, as imap_socket_read() uses that as an indicator whether list
parsing is ongoing.
2021-02-14 23:47:14 +01:00
Oswald Buddenhagen
32392adbe3 accept unsolicited FETCH responses (without payload) after all
while the spec says that the server SHOULD not send FETCH responses
about STORE FLAGS when .SILENT is used, at least gmail and fastmail seem
to do it nonetheless. also, in case of concurrent flag updates on the
affected messages such responses can be legitimately sent.

in earlier versions of mbsync this would lead to duplicate messages
piling up in the store, though that would pose no problem at that point.
2021-02-14 23:47:14 +01:00
Oswald Buddenhagen
9e3041de93 bump version 2021-02-14 23:47:14 +01:00
Nihal Jere
7a0ea1f15c use correct <poll.h> header
In POSIX, poll() should be accessible using <poll.h>, although most
implementations keep <sys/poll.h> to avoid breakage. This fixes some
warnings when building on musl.
2021-02-08 17:26:11 +01:00
Oswald Buddenhagen
062706fcbf Merge branch '1.3'
Conflicts:
	configure.ac
	src/drv_imap.c
2021-02-03 15:53:05 +01:00
Oswald Buddenhagen
e4eac03a9a bump version 2021-02-03 14:44:31 +01:00
Oswald Buddenhagen
c8b73acad2 unbreak handling of 'INBOX.' NAMESPACE again
INBOX matching must not prevent prefix (namespace) stripping, as INBOX
may be the namespace.

amends 04fc586e7.

REFMAIL: 186391612191752@vla1-ea7e194e8506.qloud-c.yandex.net
2021-02-03 14:43:11 +01:00
Anton Khirnov
fc300fd811 Set authentication id for the SASL EXTERNAL mechanism
The SASL library will refuse to use the EXTERNAL module when no auth id
is set a priori.

Tested to work with Dovecot, using TLS client certificates for
authentication.
2021-01-05 19:50:21 +01:00
Oswald Buddenhagen
e67cf01eb8 improve SASL error messages
provide context, and remove the redundant numeric codes.
2021-01-05 19:46:29 +01:00
Oswald Buddenhagen
c2e6e962b5 tune SASL-related comments
- add explanations to the callbacks
- remove bogus comment - EXTERNAL can be in fact missing (when no
  authentication id is set)
2021-01-05 19:46:29 +01:00
Oswald Buddenhagen
e295f483d9 save errno in sys_error()
the print functions prior to perror() might otherwise clobber it.
2021-01-01 14:46:31 +01:00
Oswald Buddenhagen
6e56f39fa9 autotest: remove unused boxname parameter from printbox() 2020-12-19 13:22:29 +01:00
Oswald Buddenhagen
9fbf5c2f6c autotest: pass containers by reference
this makes function prototypes a lot more useful for parameter checking.
2020-12-19 13:22:29 +01:00
Oswald Buddenhagen
4423a932f3 add forced async mode to proxy driver
to test async operation of the syncing core while using the synchronous
maildir driver, we add a mode to the proxy driver where it queues
callback invocations to the next main loop iteration.
2020-12-19 13:22:29 +01:00
Oswald Buddenhagen
be657530ee localize a variable more appropriately 2020-12-17 22:18:10 +01:00
Oswald Buddenhagen
30af61fb24 consolidate testing options behind common switch
don't pollute the namespace with random uppercase switches. instead,
have a new -T switch with suboptions, just like -D.
2020-12-17 22:18:10 +01:00
Oswald Buddenhagen
c3d91ae1e8 introduce new inheritance model based on C11 anonymous structs
the struct declarations got uglier, but their usage requires a lot fewer
explicit references to the parent struct (though some are added where
using the derived struct is more practical now).

we also use something i'd term "covariant members": derivatives of
store_t also reference derivatives of store_conf_t, etc., which
drastically cuts down the number of casts.
fwiw, to achieve this with "proper" inheritance in C++, we'd use
covariant getter functions which hide the still existing casts.

C11 is almost a decade old now, and compilers supported that feature
even longer than that, so i don't expect this to be a problem.
2020-12-17 22:18:10 +01:00
Oswald Buddenhagen
bf66f210bd add some error checking to proxy template processor
debugging is a lot easier when the unconsumed (and therefore likely
mistyped) replacements are complained about.
2020-12-17 22:18:10 +01:00
Oswald Buddenhagen
cd6f18fd2b handle indentation in proxy driver template code more flexibly
use the indentation of the placeholder, not the replacement.
this doesn't matter right now, as all placeholders are indented by one
step, but that will change soon.

the indent function cannot be inlined into the substitution, as for some
reason ^ then matches the end of the string, not the embedded line
starts (with perl v5.32). also, $1 needs to go into a temporary anyway.
2020-12-17 22:17:11 +01:00
Oswald Buddenhagen
ba7b634186 make FALLTHROUGH work with qtcreator's code model
the code model inspector claims that __GNUC__ is 10, but the #if works
only with >= 4, which is plain wrong. so just handle clang explicitly.
2020-12-16 13:42:40 +01:00
Oswald Buddenhagen
5b4766fbe4 improve docu for {Pass,User}Cmd 2020-12-12 14:56:27 +01:00
Oswald Buddenhagen
4ad82686f2 fix build with macOS keychain support
we use symbols from CoreFoundation directly, so we need to link it
explicitly.

amends 198ca65b.
2020-11-29 13:47:18 +01:00
Oswald Buddenhagen
dec4b36595 improve wording in man page 2020-10-05 13:50:23 +02:00
Oswald Buddenhagen
a9ce7be962 streamline init of type & name in imap_parse_store() 2020-10-05 13:15:28 +02:00
Oswald Buddenhagen
09341c10c5 make complaints about unrecognized keywords more verbose
tell the user in what section the keyword appeared, as that may help
spotting mistakes like stray empty lines.
2020-10-05 13:14:48 +02:00
Oswald Buddenhagen
217764bd35 complain about global options following sections
while harmless for most options, such usage is counter to the
documentation, and actually breaks CopyArrivalDate, MaxMessages, and
ExpireUnread.
2020-10-05 12:41:35 +02:00
Oswald Buddenhagen
ee39e684aa make exit from parsing Group sections less convoluted
this is a de-optimization, but it makes the code consistent with the
other sections (which do not use the shortcut due to having to
post-process the data or being encapsulated by a function call).
2020-10-05 12:31:14 +02:00
Oswald Buddenhagen
6463a72f12 remove the -cT option
it was another vestige from the compat wrapper.

amends cbac8aa75.
2020-10-05 11:56:30 +02:00
Oswald Buddenhagen
23513564df improve error handling in post-STORE UIDNEXT fallback
that's mostly hypothetical, but let's not make assumptions.

this also adds EXPUNGE response handling to make total_msgs reliable. in
principle, this affects the post-SELECT UIDNEXT fallback as well, but
there the racing window is so short that this barely improves anything.

amends 94022a67.
2020-08-24 12:51:47 +02:00
Oswald Buddenhagen
42f165ecf7 fix UIDNEXT query vs. concurrent imap_fetch_msg()
the uidnext query following message stores can be interleaved with
message fetches. that means that we cannot rely on the 1st command in
flight being that query. but instead of iterating over all commands in
flight, move the uidnext query flag to imap_store (and make sure to
check for the presence of a message body before testing it) - this
avoids the loop and an extra byte in every command.

this also makes it clear that the query is mutually exclusive with
loading messages (the untagged responses are not distinguishable).
2020-08-24 12:51:47 +02:00
Oswald Buddenhagen
f099141e42 make item tracking in parse_fetch_rsp() more uniform
amends 67ea5bea7 & a5a8783ea.
2020-08-24 12:51:42 +02:00
Oswald Buddenhagen
ec47c90554 delay allocation of msgdata.msgid field
this allows us to simplify the exit path of parse_fetch_rsp().
2020-08-05 17:59:28 +02:00