MAREN ZUBIZARRETA
2019-Oct-10 08:34 UTC
Using attachment_dir with plugin zlib corrupt mails
Hello:
I have found the same problem reported above by Patrick Cernko affecting our
system and corrupting our messages. Even worse, Outlook 2016 will no synchronize
and the clients cannot see any message, even if there is only one corrupted mail
per mailbox.
I cannot figure out a feasible workaround for our system, and I can see that
in new version 2.38 the bug is not fixed.
Will this issue be treated soon?
Thanks a lot
Maren Zubizarreta
WARNING: using attachment_dir with plugin zlib can corrupt mails
Patrick Cernko pcernko at
mpi-klsb.mpg.de<mailto:dovecot%40dovecot.org?Subject=Re:%20Re%3A%20WARNING%3A%20using%20attachment_dir%20with%20plugin%20zlib%20can%20corrupt%20mails&In-Reply-To=%3C1ab8edcc-bef4-3b41-d09a-c523674a5031%40mpi-klsb.mpg.de%3E>
Fri Jul 19 17:52:37 EEST 2019
* Previous message: index worker 2.3.7 undefined symbol
errors<https://dovecot.org/list/dovecot/2019-July/116617.html>
* Next message: Address family not supported by
protocol<https://dovecot.org/list/dovecot/2019-July/116571.html>
* Messages sorted by: [ date
]<https://dovecot.org/list/dovecot/2019-July/date.html#116570> [ thread
]<https://dovecot.org/list/dovecot/2019-July/thread.html#116570> [ subject
]<https://dovecot.org/list/dovecot/2019-July/subject.html#116570> [ author
]<https://dovecot.org/list/dovecot/2019-July/author.html#116570>
________________________________
Hello list, hello Dovecot developers,
this week, I discovered a serious bug in Dovecot, that lead to several
broken mails on our servers. The bug corrupts the first few characters
of the mail header during saving. On our setup, it was almost always
only the very first line of text, that was corrupted.
Depending on the IMAP client (they seem to request different header
fields, ... during mail access), the bug causes the imap process to hang
up the TCP connection and log errors like this:
> imap(USERNAME)<4767><TeQP4ASOTK5/AAAB>: Error: Corrupted record
in index cache file
/IMAP/mail/mailboxes/USERNAME/mdbox/mailboxes/Trash/dbox-Mails/dovecot.index.cache:
UID 489113: Broken fields in mailbox Trash:
read(attachments-connector(zlib(/IMAP/mail/mailboxes/USERNAME/mdbox/storage/m.813))):
FETCH BODY[HEADER.FIELDS (RETURN-PATH SUBJECT)] got too little data: 2 vs 122
In our case that finally grabbed my attention, the client was the users
iphone that did not display any new messages but his Thunderbird did.
The bug seems to be triggered by a bad "interaction" of attachment_dir
option and zlib plugin. If you use both, you most likely are affected,
too, except you only use zlib plugin for reading previously compressed
stored mails. That's also the workaround we use now: zlib plugin only
enabled in mail_plugins but no plugin/zlib_save set.
The bug occurs on very specific mails. Due to privacy reasons I could
not provide sample mails here. Storing such mails seems to trigger the
bug reproducible.
I attached a very minimal doveconf -n config, that can be used to
trigger the bug. If one of the developers is interested, I can try to
generate an "anonymized" version of such a specific mail that still
causes the issue. I discovered the bug on our productive systems,
running latest Dovecot 2.2 release, but the latest 2.3 I used during
debugging is affected, too.
During debugging, I also found one hint, that might help find the bug:
If you store a problematic mail with zlib_save=gz (or zlib_save=bz2) and
then disable the zlib plugin in mail_plugins, you can call
doveadm fetch -u test hdr all | grep -v ^hdr: | gzip --decompress
on test's mailbox with only that one broken mail.
This will display the beginning of the rfc822 mail text until gzip
terminates with "gzip: stdin: unexpected end of file", approximately
after twice the length of the mail HEADER. This might indicate, that
dovecot stores the uncompressed size of the header in it's data
structures although the mail is stored compressed.
I also found a very efficient way to find all affected mails in our setup:
doveadm -f flow fetch -A 'user guid mailbox uid seq flags hdr' all | \
grep -a "^[^ ]+ user=" | \
grep -avF ' hdr=Return-path: ' | \
grep -av '.* hdr=[[:print:][:space:]]*$'
(runtime for ~6M mails on our servers was 20-30min)
This can be even more optimized if you have a powerful storage system
with GNU parallel:
> doveadm user '*' | parallel "doveadm -f flow fetch -u
'{}' 'user guid mailbox uid seq flags hdr' all | grep -a
'^user=' | grep -avF ' hdr=Return-path: ' | grep -av '.*
hdr=[[:print:][:space:]]*$' || true"
(runtime for ~6M mails on our servers was ~4min)
The command will give you a list of mails that possibly are affected,
check the full output of
doveadm fetch -u USERNAME hdr guid GUID | less
to verify that the header is really broken.
On our systems I found 39 mails within ~12M mails.
I was able to recover these mails "manually" by reconstructing the
Return-Path header line, importing the fixed mails and expunging the
corrupt ones. Before importing, I had to disable zlib_save option obviously.
Best regards,
--
Patrick Cernko <pcernko at
mpi-klsb.mpg.de<https://dovecot.org/mailman/listinfo/dovecot>> +49 681
9325 5815
Joint Administration: Information Services and Technology
Max-Planck-Institute fuer Informatik & Softwaresysteme
-------------- next part --------------
# 2.3.6.1 (d124cc84b): /etc/dovecot/dovecot.conf
# OS: Linux 4.14.127.1.amd64-smp x86_64 Debian 9.9
# Hostname: adove.mpi-klsb.mpg.de
listen = *
mail_attachment_dir = /var/vmail/attachments
mail_attachment_fs = posix
mail_gid = nogroup
mail_home = /var/vmail/%u
mail_location = mdbox:~/mdbox
mail_plugins = " zlib"
mail_uid = nobody
passdb {
args = /etc/dovecot/userdb
driver = passwd-file
}
plugin {
zlib_save = gz
}
protocols = imap
userdb {
args = /etc/dovecot/userdb
driver = passwd-file
}
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 5324 bytes
Desc: S/MIME Cryptographic Signature
URL:
<https://dovecot.org/pipermail/dovecot/attachments/20190719/3da620ad/attachment-0001.p7s>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://dovecot.org/pipermail/dovecot/attachments/20191010/508eeb57/attachment-0001.html>
Can you test if https://github.com/dovecot/core/commit/5068b11e594ad7cc1f7cedf2bd9280520e0e534d.patch <https://github.com/dovecot/core/commit/5068b11e594ad7cc1f7cedf2bd9280520e0e534d.patch> fixes it for you?> On 10 Oct 2019, at 11.34, MAREN ZUBIZARRETA via dovecot <dovecot at dovecot.org> wrote: > > Hello: > > I have found the same problem reported above by Patrick Cernko affecting our system and corrupting our messages. Even worse, Outlook 2016 will no synchronize and the clients cannot see any message, even if there is only one corrupted mail per mailbox. > > I cannot figure out a feasible workaround for our system, and I can see that in new version 2.38 the bug is not fixed. > > Will this issue be treated soon? > > Thanks a lot > > Maren Zubizarreta > > > WARNING: using attachment_dir with plugin zlib can corrupt mails > > Patrick Cernko pcernko at mpi-klsb.mpg.de <mailto:dovecot%40dovecot.org?Subject=Re:%20Re%3A%20WARNING%3A%20using%20attachment_dir%20with%20plugin%20zlib%20can%20corrupt%20mails&In-Reply-To=%3C1ab8edcc-bef4-3b41-d09a-c523674a5031%40mpi-klsb.mpg.de%3E> > Fri Jul 19 17:52:37 EEST 2019 > Previous message: index worker 2.3.7 undefined symbol errors <https://dovecot.org/list/dovecot/2019-July/116617.html> > Next message: Address family not supported by protocol <https://dovecot.org/list/dovecot/2019-July/116571.html> > Messages sorted by: [ date ] <https://dovecot.org/list/dovecot/2019-July/date.html#116570> [ thread ] <https://dovecot.org/list/dovecot/2019-July/thread.html#116570> [ subject ] <https://dovecot.org/list/dovecot/2019-July/subject.html#116570> [ author ] <https://dovecot.org/list/dovecot/2019-July/author.html#116570> > Hello list, hello Dovecot developers, > > this week, I discovered a serious bug in Dovecot, that lead to several > broken mails on our servers. The bug corrupts the first few characters > of the mail header during saving. On our setup, it was almost always > only the very first line of text, that was corrupted. > > Depending on the IMAP client (they seem to request different header > fields, ... during mail access), the bug causes the imap process to hang > up the TCP connection and log errors like this: > > > imap(USERNAME)<4767><TeQP4ASOTK5/AAAB>: Error: Corrupted record in index cache file /IMAP/mail/mailboxes/USERNAME/mdbox/mailboxes/Trash/dbox-Mails/dovecot.index.cache: UID 489113: Broken fields in mailbox Trash: read(attachments-connector(zlib(/IMAP/mail/mailboxes/USERNAME/mdbox/storage/m.813))): FETCH BODY[HEADER.FIELDS (RETURN-PATH SUBJECT)] got too little data: 2 vs 122 > > In our case that finally grabbed my attention, the client was the users > iphone that did not display any new messages but his Thunderbird did. > > The bug seems to be triggered by a bad "interaction" of attachment_dir > option and zlib plugin. If you use both, you most likely are affected, > too, except you only use zlib plugin for reading previously compressed > stored mails. That's also the workaround we use now: zlib plugin only > enabled in mail_plugins but no plugin/zlib_save set. > > The bug occurs on very specific mails. Due to privacy reasons I could > not provide sample mails here. Storing such mails seems to trigger the > bug reproducible. > > > I attached a very minimal doveconf -n config, that can be used to > trigger the bug. If one of the developers is interested, I can try to > generate an "anonymized" version of such a specific mail that still > causes the issue. I discovered the bug on our productive systems, > running latest Dovecot 2.2 release, but the latest 2.3 I used during > debugging is affected, too. > > During debugging, I also found one hint, that might help find the bug: > If you store a problematic mail with zlib_save=gz (or zlib_save=bz2) and > then disable the zlib plugin in mail_plugins, you can call > > doveadm fetch -u test hdr all | grep -v ^hdr: | gzip --decompress > > on test's mailbox with only that one broken mail. > This will display the beginning of the rfc822 mail text until gzip > terminates with "gzip: stdin: unexpected end of file", approximately > after twice the length of the mail HEADER. This might indicate, that > dovecot stores the uncompressed size of the header in it's data > structures although the mail is stored compressed. > > > I also found a very efficient way to find all affected mails in our setup: > > doveadm -f flow fetch -A 'user guid mailbox uid seq flags hdr' all | \ > grep -a "^[^ ]+ user=" | \ > grep -avF ' hdr=Return-path: ' | \ > grep -av '.* hdr=[[:print:][:space:]]*$' > (runtime for ~6M mails on our servers was 20-30min) > > This can be even more optimized if you have a powerful storage system > with GNU parallel: > > doveadm user '*' | parallel "doveadm -f flow fetch -u '{}' 'user guid mailbox uid seq flags hdr' all | grep -a '^user=' | grep -avF ' hdr=Return-path: ' | grep -av '.* hdr=[[:print:][:space:]]*$' || true" > (runtime for ~6M mails on our servers was ~4min) > > The command will give you a list of mails that possibly are affected, > check the full output of > > doveadm fetch -u USERNAME hdr guid GUID | less > > to verify that the header is really broken. > > On our systems I found 39 mails within ~12M mails. > > I was able to recover these mails "manually" by reconstructing the > Return-Path header line, importing the fixed mails and expunging the > corrupt ones. Before importing, I had to disable zlib_save option obviously. > > Best regards, > -- > Patrick Cernko <pcernko at mpi-klsb.mpg.de <https://dovecot.org/mailman/listinfo/dovecot>> +49 681 9325 5815 > Joint Administration: Information Services and Technology > Max-Planck-Institute fuer Informatik & Softwaresysteme > -------------- next part -------------- > # 2.3.6.1 (d124cc84b): /etc/dovecot/dovecot.conf > # OS: Linux 4.14.127.1.amd64-smp x86_64 Debian 9.9 > # Hostname: adove.mpi-klsb.mpg.de <http://adove.mpi-klsb.mpg.de/> > listen = * > mail_attachment_dir = /var/vmail/attachments > mail_attachment_fs = posix > mail_gid = nogroup > mail_home = /var/vmail/%u > mail_location = mdbox:~/mdbox > mail_plugins = " zlib" > mail_uid = nobody > passdb { > args = /etc/dovecot/userdb > driver = passwd-file > } > plugin { > zlib_save = gz > } > protocols = imap > userdb { > args = /etc/dovecot/userdb > driver = passwd-file > } > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: smime.p7s > Type: application/pkcs7-signature > Size: 5324 bytes > Desc: S/MIME Cryptographic Signature > URL: <https://dovecot.org/pipermail/dovecot/attachments/20190719/3da620ad/attachment-0001.p7s <https://dovecot.org/pipermail/dovecot/attachments/20190719/3da620ad/attachment-0001.p7s>>-------------- next part -------------- An HTML attachment was scrubbed... URL: <https://dovecot.org/pipermail/dovecot/attachments/20191010/2e86934b/attachment-0001.html>
at least for me it didn't fix. still see in logs: Error: lzma.read(/var/spool/mail/telsch/storage/m.11800): corrupted data at 110015 before i upgrade from 2.3.4.1 to 2.3.8 + your patch i noticed i can access the mails with alpine and roundcube but not with thunderbird. On 10.10.19 11:38, Timo Sirainen via dovecot wrote:> Can you test if > https://github.com/dovecot/core/commit/5068b11e594ad7cc1f7cedf2bd9280520e0e534d.patch?fixes > it for you? > >> On 10 Oct 2019, at 11.34, MAREN ZUBIZARRETA via dovecot >> <dovecot at dovecot.org <mailto:dovecot at dovecot.org>> wrote: >> >> Hello: >> ? I have found the same problem reported above by Patrick Cernko >> affecting our system and corrupting our messages. Even worse, Outlook >> 2016 will no synchronize and the clients cannot see any message, even >> if there is only one corrupted mail per mailbox. >> ? I cannot figure out a feasible workaround for our system, and I can >> see that in new version 2.38 the bug is not fixed. >> Will this issue be treated soon? >> Thanks a lot >> ???? Maren Zubizarreta >> >> >> WARNING: using attachment_dir with plugin zlib can corrupt mails >> >> *Patrick Cernko*pcernko at mpi-klsb.mpg.de >> <mailto:dovecot%40dovecot.org?Subject=Re:%20Re%3A%20WARNING%3A%20using%20attachment_dir%20with%20plugin%20zlib%20can%20corrupt%20mails&In-Reply-To=%3C1ab8edcc-bef4-3b41-d09a-c523674a5031%40mpi-klsb.mpg.de%3E> >> /Fri Jul 19 17:52:37 EEST 2019/ >> >> * Previous message: index worker 2.3.7 undefined symbol errors >> <https://dovecot.org/list/dovecot/2019-July/116617.html> >> * Next message: Address family not supported by protocol >> <https://dovecot.org/list/dovecot/2019-July/116571.html> >> * *Messages sorted by:*[ date ] >> <https://dovecot.org/list/dovecot/2019-July/date.html#116570>[ >> thread ] >> <https://dovecot.org/list/dovecot/2019-July/thread.html#116570>[ >> subject ] >> <https://dovecot.org/list/dovecot/2019-July/subject.html#116570>[ >> author ] >> <https://dovecot.org/list/dovecot/2019-July/author.html#116570> >> >> ------------------------------------------------------------------------ >> Hello list, hello Dovecot developers, >> this week, I discovered a serious bug in Dovecot, that lead to several >> broken mails on our servers. The bug corrupts the first few characters >> of the mail header during saving. On our setup, it was almost always >> only the very first line of text, that was corrupted. >> Depending on the IMAP client (they seem to request different header >> fields, ... during mail access), the bug causes the imap process to hang >> up the TCP connection and log errors like this: >> >/imap(USERNAME)<4767><TeQP4ASOTK5/AAAB>: Error: Corrupted record in >> index cache file >> /IMAP/mail/mailboxes/USERNAME/mdbox/mailboxes/Trash/dbox-Mails/dovecot.index.cache: >> UID 489113: Broken fields in mailbox Trash: >> read(attachments-connector(zlib(/IMAP/mail/mailboxes/USERNAME/mdbox/storage/m.813))): >> FETCH BODY[HEADER.FIELDS (RETURN-PATH SUBJECT)] got too little data: 2 >> vs 122/ >> In our case that finally grabbed my attention, the client was the users >> iphone that did not display any new messages but his Thunderbird did. >> The bug seems to be triggered by a bad "interaction" of attachment_dir >> option and zlib plugin. If you use both, you most likely are affected, >> too, except you only use zlib plugin for reading previously compressed >> stored mails. That's also the workaround we use now: zlib plugin only >> enabled in mail_plugins but no plugin/zlib_save set. >> The bug occurs on very specific mails. Due to privacy reasons I could >> not provide sample mails here. Storing such mails seems to trigger the >> bug reproducible. >> I attached a very minimal doveconf -n config, that can be used to >> trigger the bug. If one of the developers is interested, I can try to >> generate an "anonymized" version of such a specific mail that still >> causes the issue. I discovered the bug on our productive systems, >> running latest Dovecot 2.2 release, but the latest 2.3 I used during >> debugging is affected, too. >> During debugging, I also found one hint, that might help find the bug: >> If you store a problematic mail with zlib_save=gz (or zlib_save=bz2) and >> then disable the zlib plugin in mail_plugins, you can call >> doveadm fetch -u test hdr all | grep -v ^hdr: | gzip --decompress >> on test's mailbox with only that one broken mail. >> This will display the beginning of the rfc822 mail text until gzip >> terminates with "gzip: stdin: unexpected end of file", approximately >> after twice the length of the mail HEADER. This might indicate, that >> dovecot stores the uncompressed size of the header in it's data >> structures although the mail is stored compressed. >> I also found a very efficient way to find all affected mails in our setup: >> doveadm -f flow fetch -A 'user guid mailbox uid seq flags hdr' all | \ >> ?? grep -a "^[^ ]+ user=" | \ >> ?? grep -avF ' hdr=Return-path: ' | \ >> ?? grep -av '.* hdr=[[:print:][:space:]]*$' >> (runtime for ~6M mails on our servers was 20-30min) >> This can be even more optimized if you have a powerful storage system >> with GNU parallel: >> >/doveadm user '*' | parallel "doveadm -f flow fetch -u '{}' 'user guid >> mailbox uid seq flags hdr' all | grep -a '^user=' | grep -avF ' >> hdr=Return-path: ' | grep -av '.* hdr=[[:print:][:space:]]*$' || true"/ >> (runtime for ~6M mails on our servers was ~4min) >> The command will give you a list of mails that possibly are affected, >> check the full output of >> doveadm fetch -u USERNAME hdr guid GUID | less >> to verify that the header is really broken. >> On our systems I found 39 mails within ~12M mails. >> I was able to recover these mails "manually" by reconstructing the >> Return-Path header line, importing the fixed mails and expunging the >> corrupt ones. Before importing, I had to disable zlib_save option >> obviously. >> Best regards, >> -- >> Patrick Cernko <pcernko at mpi-klsb.mpg.de >> <https://dovecot.org/mailman/listinfo/dovecot>> +49 681 9325 5815 >> Joint Administration: Information Services and Technology >> Max-Planck-Institute fuer Informatik & Softwaresysteme >> -------------- next part -------------- >> # 2.3.6.1 (d124cc84b): /etc/dovecot/dovecot.conf >> # OS: Linux 4.14.127.1.amd64-smp x86_64 Debian 9.9 >> # Hostname: adove.mpi-klsb.mpg.de <http://adove.mpi-klsb.mpg.de/> >> listen = * >> mail_attachment_dir = /var/vmail/attachments >> mail_attachment_fs = posix >> mail_gid = nogroup >> mail_home = /var/vmail/%u >> mail_location = mdbox:~/mdbox >> mail_plugins = " zlib" >> mail_uid = nobody >> passdb { >> ? args = /etc/dovecot/userdb >> ? driver = passwd-file >> } >> plugin { >> ? zlib_save = gz >> } >> protocols = imap >> userdb { >> ? args = /etc/dovecot/userdb >> ? driver = passwd-file >> } >> -------------- next part -------------- >> A non-text attachment was scrubbed... >> Name: smime.p7s >> Type: application/pkcs7-signature >> Size: 5324 bytes >> Desc: S/MIME Cryptographic Signature >> URL: >> <https://dovecot.org/pipermail/dovecot/attachments/20190719/3da620ad/attachment-0001.p7s> >
Hello list,
i'm running an internal dovecot instance with working managesieve. But
on my external dovecot-proxy instance i got an internal error. Nothing
logs on internal dovecot.
Nov 06 14:55:12 managesieve-login: Error: proxy: Remote sent invalid
response: * OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE
IDLE LITERAL+ AUTH=PLAIN AUTH=LOGIN AUTH=GSSAPI] Dovecot (Ubuntu)
ready.??: user=<user>, method=PLAIN, rip=remote_ip, lip=local_ip, TLS,
session=</G/K5a2WzMFNDVcl>
Nov 06 14:55:12 managesieve-login: Debug: server.intra.lan: SSL alert:
close notify
Nov 06 14:55:12 managesieve-login: Info: Aborted login (internal
failure, 1 successful auths): user=<user>, method=PLAIN, rip=remote_ip,
lip=local_ip, TLS, session=</G/K5a2WzMFNDVcl>
# 2.3.4.1 (f79e8e7e4): /etc/dovecot-proxy/dovecot-proxy.conf
# Pigeonhole version 0.5.4 ()
# OS: Linux 4.15.0-66-generic x86_64 Ubuntu 18.04.3 LTS
# Hostname: server.lan
auth_username_format = %Ln
base_dir = /var/run/dovecot-proxy/
instance_name = dovecot-proxy
listen = <myip>
log_path = /var/log/dovecot/dovecot-proxy.log
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope
encoded-character vacation subaddress comparator-i;ascii-numeric
relational regex imap4flags copy include variables body enotify
environment mailbox date index ihave duplicate mime foreverypart extracttext
passdb {
args = /etc/dovecot-proxy/dovecot-ldap-passdb.conf.ext
default_fields = proxy=y host=server.intra.lan port=993 ssl=yes
master=proxy pass=#hidden_use-P_to_show#
driver = ldap
}
protocols = imap sieve
service auth {
unix_listener /var/spool/postfix/private/proxy-auth {
mode = 0666
}
}
service imap-login {
inet_listener imap {
port = 0
}
inet_listener imaps {
port = 993
ssl = yes
}
}
ssl = required
ssl_ca = </etc/ssl/mycacert.pem
ssl_cert = </etc/ssl/mycert.pem
ssl_cipher_list = ALL:!SSLv2:!ADH:!LOW:!MEDIUM:!aNULL:!EXP
ssl_dh = # hidden, use -P to show it
ssl_key = # hidden, use -P to show it
ssl_min_protocol = TLSv1.2
ssl_require_crl = no
userdb {
args = /etc/dovecot-proxy/dovecot-ldap-userdb.conf.ext
driver = ldap
}
protocol imap {
mail_max_userip_connections = 20
ssl_cert = </etc/ssl/letsencrypt.ca-bundle
ssl_key = # hidden, use -P to show it
}
protocol sieve {
ssl_cert = </etc/ssl/letsencrypt.ca-bundle
ssl_key = # hidden, use -P to show it
}
Possibly Parallel Threads
- Using attachment_dir with plugin zlib corrupt mails
- WARNING: using attachment_dir with plugin zlib can corrupt mails
- replication dropped imap flags
- replication and .dovecot.lda-dupes
- Am I right to assume certificate renewal with the same filename requires a dovecot reload/restart