dovecot - Mar 2018 - [ext] Re: Panic: file smtp-address.c: line 530 (smtp_address_write): assertion failed: (smtp_char_is_qpair(*p))

On 04/03/18 09:55, Stephan Bosch wrote:
> Op 3/4/2018 om 9:07 AM schreef John Fawcett:
>> On 03/03/18 22:10, Stephan Bosch wrote:
>>> Clearly, the relevant specifications don't allow UTF-8 in the
local part
>>> without email address internationalization (EAI), which Dovecot
does not
>>> support nor announce yet (although that should be mended somewhat
soon).
>>> My preferred fix for now would be to reject addresses like that,
which
>>> would maybe still mean that this message is rejected entirely.
>>> Alternatively, that address at least needs to be skipped, ignored,
or
>>> modified: all of which aren't very nice things to do. The
alternative is
>>> forwarding this violation to other systems, which is seldom
acceptable
>>> either.
>>>
>> Would accepting UTF8 local part in the From header have any negative
>> consequences for Dovecot? If it does not I would accept it, based on
the
>> fact that it maintains greater interoperability with other systems.
>> John
>>
> Depends on what causes the panic. I don't know that yet.
>
> Regards,
>
> Stephan.
>From the code in lib-smtp/smtp-address.c function smtp_address_write, it
looks as though the assertion will happen whenever there is a non ascii
char that is also non qpair in the local part, ie
!smtp_char_is_atext(*p) and !smtp_char_is_qpair(*p).

I wasn't able to confirm it since I've not moved to 2.3 yet and the 2.2
code is different, but this should happen if there are characters from
0x01 to 0x1f or from 0x7f to 0xff in the local part.

By the way I noticed that if Postfix has SMTPUTF8 enabled, then it won't
hand off messages with this content to Dovecot since Dovecot does not
advertise support for SMTPUTF8. If SMTPUTF8 is unavailable or disabled
then Postfix passes on those characters. I suspect that Ralph has
SMTPUTF8 turned off.

John

> I wasn't able to confirm it since I've not moved to 2.3 yet and the
2.2
> code is different, but this should happen if there are characters from
> 0x01 to 0x1f or from 0x7f to 0xff in the local part.
Yeah, I was running 2.2.x prior to my upgrade and never encountered
this.
> By the way I noticed that if Postfix has SMTPUTF8 enabled, then it
won't
> hand off messages with this content to Dovecot since Dovecot does not
> advertise support for SMTPUTF8. If SMTPUTF8 is unavailable or disabled
> then Postfix passes on those characters. I suspect that Ralph has
> SMTPUTF8 turned off.
Ah I see:

When a message is received with the SMTPUTF8 request, Postfix will
deliver the message to a non-SMTPUTF8 SMTP or LMTP server ONLY if:

* No message header value contains UTF-8.
* The envelope sender address contains no UTF-8,
* No envelope recipient address for that specific SMTP/LMTP delivery transaction
contains UTF-8.

I wonder if this will break a lot.



-- 
Ralf Hildebrandt
  Gesch?ftsbereich IT | Abteilung Netzwerk
  Charit? - Universit?tsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  ralf.hildebrandt at charite.de | https://www.charite.de

> From the code in lib-smtp/smtp-address.c function smtp_address_write, it
> looks as though the assertion will happen whenever there is a non ascii
> char that is also non qpair in the local part, ie
> !smtp_char_is_atext(*p) and !smtp_char_is_qpair(*p).
Could somebody please point me in the direction how to obtain a
coredump here?

-- 
Ralf Hildebrandt
  Gesch?ftsbereich IT | Abteilung Netzwerk
  Charit? - Universit?tsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  ralf.hildebrandt at charite.de | https://www.charite.de
	    
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* Ralf Hildebrandt <Ralf.Hildebrandt at
charite.de>:
> > From the code in lib-smtp/smtp-address.c function smtp_address_write,
it
> > looks as though the assertion will happen whenever there is a non
ascii
> > char that is also non qpair in the local part, ie
> > !smtp_char_is_atext(*p) and !smtp_char_is_qpair(*p).
> 
> Could somebody please point me in the direction how to obtain a
> coredump here?
I found
sysctl -w fs.suid_dumpable=2
but where will coredumps be written?

-- 
Ralf Hildebrandt
  Gesch?ftsbereich IT | Abteilung Netzwerk
  Charit? - Universit?tsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  ralf.hildebrandt at charite.de | https://www.charite.de
	    
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