Re: Excessive APPENDLIMIT response [Re: Android after Cyrus upgrade]

Hi,

> APPENDLIMIT is controlled by *maxmessagesize *in imapd.conf

Wouldn't it make sense to define a default for maxmessagesize with a
reasonable value, like 100m or so? I mean just to make broken clients
happy :)

Regards,
Simon

>
>
> On 5/10/23 9:10 AM, Nic Bernstein wrote:
>> Edda,
>> Great catch!  Indeed, the APPENDLIMIT extension, defined in RFC7889*,
>> was added to Cyrus in 2021:
>>
>>     commit 40793dfde8c96797d86f80e9f461bea61bca3bc9
>>     Author: Ken Murchison <[email protected]>
>>     Date:   Sat Jan 30 09:10:00 2021 -0500
>>
>>         imapd.c: Advertise APPENDLIMIT= capability
>>
>> As noted, this is defined in imap/imapc:
>>
>>     { "APPENDLIMIT=",          CAPA_POSTAUTH|CAPA_VALUE,         /* RFC
>> 7889 */
>>            { .value = { "%2$" PRIi64, .i64p = &maxsize } }         },
>>
>> So the question becomes, is this a bug in Cyrus or in FairEmail? Given
>> that FairEmail is the only application complaining about it, I'd
>> suggest they're the buggy ones.  But I could be wrong.
>>
>> *It's worth noting* that there's appears to be no configuration option
>> [i.e. imapd.conf(5)] for appendlimit (looked for *limit, *maxsize,
>> etc.).  Is this a bug?  The number advertised, 18446744071562067968,
>> is the C compiler's maximum object size.  This seems awfully large for
>> most mail systems, and doesn't serve any legitimate purpose as it
>> currently sits.
>>
>> Cheers,
>>     -nic
>>
>>
>> *https://www.rfc-editor.org/rfc/rfc7889
>>
>>
>> On 5/10/23 07:20, Edda wrote:
>>> Hello Vladas,
>>>
>>> FairEmail is complaining about a "too long" Long. It's in the source
>>> code of FairEmail in
>>> ./app/src/main/java//eu/faircode/email/EmailService.java at:
>>>
>>>     Long getMaxSize() throws MessagingException {
>>>         // https://support.google.com/mail/answer/6584#limit
>>>
>>>         String size;
>>>         if (iservice instanceof SMTPTransport) {
>>>             // https://tools.ietf.org/html/rfc1870
>>>             size = getTransport().getExtensionParameter("SIZE");
>>>         } else if (iservice instanceof IMAPStore) {
>>>             // https://tools.ietf.org/html/rfc7889
>>>             size = ((IMAPStore) iservice).getCapability("APPENDLIMIT");
>>>         } else
>>>             return null;
>>>
>>>         if (!TextUtils.isEmpty(size) && TextUtils.isDigitsOnly(size)) {
>>> *            long s = Long.parseLong(size);*
>>>             if (s != 0) // Not infinite
>>>                 return s;
>>>         }
>>>
>>>         return null;
>>>     }
>>>
>>> String "size" is indeed too long for a Long: "18446744071562067968"
>>>
>>> Since it's an IMAP Service, APPENDLIMIT seems to be the problem.
>>>
>>> I just checked at your server:
>>>
>>> . CAPABILITY
>>> * CAPABILITY IMAP4rev1 LITERAL+ ID ENABLE ACL ANNOTATE-EXPERIMENT-1
>>> BINARY CATENATE CHILDREN CONDSTORE CREATE-SPECIAL-USE ESEARCH ESORT
>>> LIST-EXTENDED LIST-MYRIGHTS LIST-STATUS MAILBOX-REFERRALS METADATA
>>> MOVE MULTIAPPEND NAMESPACE OBJECTID PREVIEW QRESYNC QUOTA
>>> RIGHTS=kxten SAVEDATE SEARCH=FUZZY SORT SORT=DISPLAY SPECIAL-USE
>>> STATUS=SIZE THREAD=ORDEREDSUBJECT THREAD=REFERENCES UIDPLUS UNSELECT
>>> URLAUTH URLAUTH=BINARY WITHIN DIGEST=SHA1 LIST-METADATA
>>> NO_ATOMIC_RENAME SCAN SORT=MODSEQ SORT=UID THREAD=REFS
>>> X-CREATEDMODSEQ X-REPLICATION X-SIEVE-MAILBOX XLIST XMOVE
>>> AUTH=SCRAM-SHA-512-PLUS AUTH=SCRAM-SHA-512 AUTH=SCRAM-SHA-384-PLUS
>>> AUTH=SCRAM-SHA-384 AUTH=SCRAM-SHA-256-PLUS AUTH=SCRAM-SHA-256
>>> AUTH=SCRAM-SHA-224-PLUS AUTH=SCRAM-SHA-224 AUTH=SCRAM-SHA-1-PLUS
>>> AUTH=SCRAM-SHA-1 AUTH=GSS-SPNEGO AUTH=GSSAPI AUTH=DIGEST-MD5 AUTH=OTP
>>> AUTH=NTLM AUTH=CRAM-MD5 AUTH=LOGIN AUTH=PLAIN SASL-IR XCONVERSATIONS
>>> COMPRESS=DEFLATE X-QUOTA=STORAGE X-QUOTA=MESSAGE
>>> X-QUOTA=X-ANNOTATION-STORAGE X-QUOTA=X-NUM-FOLDERS IDLE
>>> *APPENDLIMIT=18446744071562067968*
>>>
>>> APPENDLIMIT is advertised prior to login. Therefore it doesn't show
>>> up in the telemetry logs I think.
>>>
>>> I don't have cyrus 3.6.1 anywhere yet, but I think you should look at
>>> maxmessagesize in imapd.conf
>>>
>>> Best regards,
>>> Edda
>>>
>>>
>>> Am 09.05.23 um 14:20 schrieb vladas via Info:
>>>> I have read the man
>>>> <https://sala.online.lt/doc/cyrus-imapd/html/imap/reference/manpages/index.html>
>>>> pages, release
>>>> <https://www.cyrusimap.org/imap/download/release-notes/3.6/x/3.6.0.html>
>>>> and upgrade <https://www.cyrusimap.org/imap/download/upgrade.html>
>>>> notes again,  checked cyrus.conf and imapd.conf settings, restarted
>>>> Cyrus imapd and saslauthd daemons, verified configuration and spool
>>>> files — and still found no cause.
>>>>
>>>> Then I completely removed my account and all assets from FairEmail
>>>> on my Android Motorola phone, Asus pad, and then set them again
>>>> manually, step by step, with different connection modes (SSL/TLS
>>>> :933, STARTTLS :143, insecure) — all of them are accepted, but the
>>>> sync soon gets stuck and a warning message is issued with always the
>>>> same error code:
>>>>
>>>>> For input string: "1844674407152067968"
>>>>
>>>> FairEmail is the best MUA I have ever seen: lean, secure, fast, with
>>>> a clear and convenient user interface — despite of being
>>>> full-featured and standards-compliant, with hundred of preconfigured
>>>> settings of commercial providers, and with detailed logs:
>>>>
>>>>
>>>>
>>>> My mail is hosted on sala.online.lt [217.147.40.110] and serves,
>>>> among others, the on.lt domain. Faircode.eu is a domain of the
>>>> developer. This log is laid out here from bottom to the top. Sorry,
>>>> I am not a programmer and do not understand this log. I guess there
>>>> is a tiny software bug, that only emerged after the upgrade.
>>>
>>>
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>>>
>>
>> --
>> Nic [email protected]
>> https://www.nicbernstein.com
> 
> --
> Kenneth Murchison
> Senior Software Developer
> Fastmail US LLC



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