Re: Crash when using dict quotas with sqlite database

3 Feb 2019 · *=*


      ...and then I found the commit I was looking for. It's fixed in https://github.com/dovecot/core/commit/ab80122c68bfe5c3dbae2b4d782f418112271...
Aki
...
On 03 February 2019 at 20:06 Aki Tuomi aki.tuomi@open-xchange.com wrote:
Can you try out the attached patch?
Aki
...
On 03 February 2019 at 17:17 Marcel Menzel mail@mcl.gg wrote:
All I did was
    - create a sqlite database with: # sqlite3 /tmp/storage.db (/run
only to test for perm issues in other folders)
    - change it's owner to mail (that's the user owning the mail files):
# chown mail:mail /tmp/storage.db
    - point dovecot to the file in "dovecot-dict-sql.conf.ext" with
"connect = /tmp/storage.db"
    - enable quota in "90-quota.conf" with "quota = dict:User
quota::proxy::quota" in the plugin section (sample config file taken
from sources)
    - changing the dict section in dovecot.conf to:
dict {
quota = sqlite:/etc/dovecot/dovecot-dict-sql.conf.ext
expire = sqlite:/etc/dovecot/dovecot-dict-sql.conf.ext
}
After this, a simple "doveadm quota recalc -u mail@mcl.gg" is enough to
cause a dict crash.
While tinkering with the config (and making a small mistake where i
moved the file and dovecot complaining about
doveadm: Error: dict quota: Quota update failed: dict-server returned
failure: sql dict: commit failed: out of memory (reply took 0.041 secs
(0.001 in dict wait, 0.000 in other ioloops, 0.001 in locks, async-id
reply 0.000 secs ago, started on dict-server 0.041 secs ago, took 0.000
secs)) - Quota is now desynced
And reloading it afterwards, my log got filled with like 200 lines
containing
dovecot[6213]: dict(6301): Warning: Event 0x67a90293830 leaked
(parent=0x67a9027c890): driver-sqlite.c:173

Marcel

Am 03.02.2019 um 15:57 schrieb Aki Tuomi:
...
Can you provide steps on how to reproduce this? Tracked as DOP-899
...
On 03 February 2019 at 16:50 Aki Tuomi < aki.tuomi@open-xchange.com
mailto:aki.tuomi@open-xchange.com> wrote:
Right it was already in 2.3.4. Looking more closely this looks like
use after free. We'll look into this.
Aki
...
On 03 February 2019 at 16:44 Marcel Menzel < mail@mcl.gg
mailto:mail@mcl.gg> wrote:
Hello Aki,
unfortunately, this patch is already in my source files, as patch
refuses to apply it:
-> Applying patch fix-sqlite.patch
patching file src/lib-sql/driver-sqlite.c
Reversed (or previously applied) patch detected! Skipping patch.
2 out of 2 hunks ignored -- saving rejects to file
src/lib-sql/driver-sqlite.c.rej
I verified it by looking in the source code and indeed, this patch is
already applied.

Marcel

Am 03.02.2019 um 15:25 schrieb Aki Tuomi:
...
> Can you try if applying
>
>
https://github.com/dovecot/core/commit/b291ff1fd61b47639a2db99bd858c9511945f...
...
> >
> helps?
>
> Aki
> > > On 03 February 2019 at 16:20 Marcel Menzel < mail@mcl.gg
mailto:mail@mcl.gg
> mailto:mail@mcl.gg>> wrote:
>
> > >
> >>
> Hello Aki,
>
> Arch Linux doesn't have install-able debug symbols for Dovecot.
That's
> why I just compiled the package for myself with enabled debug
symbols
> (by editing the makepkg.conf).
>
> I've attached the output from gdb's bt full.
>
> - Marcel
>
> Am 03.02.2019 um 14:45 schrieb Aki Tuomi:
>> You need to install debug symbols. Not sure how this is done in
arch
>> linux though.
>> Aki
>>> On 03 February 2019 at 15:02 Marcel Menzel < mail@mcl.gg
mailto:mail@mcl.gg
>>> mailto:mail@mcl.gg>
>>> mailto:mail@mcl.gg mailto:mail@mcl.gg>>> wrote:
> >>
> >> Hello John,
> >>
> >> I tried (until now) to get a valuable backtrace, but it seems
that
> GDB
> >> can't resolve all symbols.
> >> This is what systemd-coredump is giving me:
> >>
> >> Stack trace of thread 22359:
> >> #0 0x0000638167eaf062 event_unref (libdovecot.so.0)
> >> #1 0x000004a58a212151 n/a (dict)
> >> #2 0x000004a58a211333 n/a (dict)
> >> #3 0x000004a58a20514d n/a (dict)
> >> #4 0x0000638167e556f2 dict_transaction_begin (libdovecot.so.0)
> >> #5 0x000004a58a203b06 n/a (dict)
> >> #6 0x000004a58a2045ff dict_command_input (dict)
> >> #7 0x000004a58a202a31 n/a (dict)
> >> #8 0x000004a58a202b35 n/a (dict)
> >> #9 0x0000638167eaacfd io_loop_call_io (libdovecot.so.0)
> >> #10 0x0000638167eac635 io_loop_handler_run_internal
(libdovecot.so.0)
> >> #11 0x0000638167eaadc7 io_loop_handler_run (libdovecot.so.0)
> >> #12 0x0000638167eaaf68 io_loop_run (libdovecot.so.0)
> >> #13 0x0000638167e1b36a master_service_run (libdovecot.so.0)
> >> #14 0x000004a58a202300 main (dict)
> >> #15 0x0000638167a17223 __libc_start_main (libc.so.6)
> >> #16 0x000004a58a2023fe _start (dict)
> >>
> >> GDB's "bt full" won't give anything more here, I might compile
> Dovecot
> >> with debug symbols enabled as soon as I have a little more time:
> >>
> >> (gdb) bt full
> >> #0 0x0000638167eaf062 in event_unref () from
> >> /usr/lib/dovecot/libdovecot.so.0
> >> No symbol table info available.
> >> #1 0x000004a58a212151 in ?? ()
> >> No symbol table info available.
> >> #2 0x000004a58a211333 in ?? ()
> >> No symbol table info available.
> >> #3 0x000004a58a20514d in ?? ()
> >> No symbol table info available.
> >> #4 0x0000638167e556f2 in dict_transaction_begin () from
> >> /usr/lib/dovecot/libdovecot.so.0
> >> No symbol table info available.
> >> #5 0x000004a58a203b06 in ?? ()
> >> No symbol table info available.
> >> #6 0x000004a58a2045ff in dict_command_input ()
> >> No symbol table info available.
> >> #7 0x000004a58a202a31 in ?? ()
> >> No symbol table info available.
> >> #8 0x000004a58a202b35 in ?? ()
> >> No symbol table info available.
> >> #9 0x0000638167eaacfd in io_loop_call_io () from
> >> /usr/lib/dovecot/libdovecot.so.0
> >> No symbol table info available.
> >> #10 0x0000638167eac635 in io_loop_handler_run_internal () from
> >> /usr/lib/dovecot/libdovecot.so.0
> >> No symbol table info available.
> >> #11 0x0000638167eaadc7 in io_loop_handler_run () from
> >> /usr/lib/dovecot/libdovecot.so.0
> >> No symbol table info available.
> >> #12 0x0000638167eaaf68 in io_loop_run () from
> >> /usr/lib/dovecot/libdovecot.so.0
> >> No symbol table info available.
> >> #13 0x0000638167e1b36a in master_service_run () from
> >> /usr/lib/dovecot/libdovecot.so.0
> >> No symbol table info available.
> >> #14 0x000004a58a202300 in main ()
> >> No symbol table info available.
> >>
> >> - Marcel
> >>
> >> Am 03.02.2019 um 09:08 schrieb John Fawcett:
> >>> On 01/02/2019 20:40, Marcel Menzel wrote:
> >>>> Hello,
> >> >>
> >> >> After I configured a SQLite backed dict quota backend, the
dict
> >> process
> >> >> crashes every time a quota operation is happening.
> >> >>
> >> >> SQLite: 3.26.0
> >> >>
> >> >> Dovecot: 2.3.4 (0ecbaf23d)
> >> >>
> >> >> Linux: 4.20.4.a-1-hardened #1 SMP PREEMPT Fri Jan 25
01:24:51 CET
> >> 2019
> >> >> x86_64 GNU/Linux (Arch Linux)
> >> >>
> >> >> Filesystem: BTRFS
> >> >>
> >> >>
> >> >> I can't get any debug output from Dovecot, even after setting
> >> log_debug
> >> >> = cat:* event:* source:* field:*=*
> >> >>
> >> >> dovecot[6457]: dict(6687): Debug: sqlite: Finished query
'BEGIN
> >> >> TRANSACTION' in 0 msecs
> >> >> dovecot[6457]: dict(6687): Fatal: master: service(dict): child
> 6687
> >> >> killed with signal 11 (core dumped)
> >> >>
> >> >>
> >> >> I've attached the output of dovecot -n and the coredump
file from
> >> >> systemd-coredump.
> >> >>
> >> >>
> >> >> Kind regards,
> >> >>
> >> >> Marcel Menzel
> >> >>
> >>> Any chance of posting a backtrace?
> >>> John
> >
>> ---
>> Aki Tuomi
...
> ---
Aki Tuomi
>

Aki Tuomi

Aki Tuomi