[exim-dev] [Bug 2215] SIGSEGV in dns_basic_lookup()

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Author: admin
Date:  
To: exim-dev
Subject: [exim-dev] [Bug 2215] SIGSEGV in dns_basic_lookup()
https://bugs.exim.org/show_bug.cgi?id=2215

--- Comment #1 from Wolfgang Breyha <wbreyha@???> ---
Some details from the hosts which fail very often. It seems that my DKIM ACL
causes this here since I use those ADSP lookup config lines only on them
because I forgot to remove them long time ago. They are legacy, but maybe they
are the best lead currently:

acl_check_dkim:

  warn    set acl_m_adsp       = ${lookup
dnsdb{defer_never,txt=_adsp._domainkey.$dkim_cur_signer}{$value}{unknown}}


  # add DKIM-Header before SA runs
  warn    add_header  = X-Univie-DKIM-Check: header.i=@$dkim_cur_signer
adsp:$acl_m_adsp result:$dkim_verify_status $dkim_verify_reason
          log_message = DKIM: header.i=$dkim_cur_signer adsp:$acl_m_adsp
result:$dkim_verify_status $dkim_verify_reason


accept

and
dkim_verify_signers = ${if def:rh_from:{${domain:$rh_from:}:}{}}${if
def:rh_sender:{${domain:$rh_sender:}:}{}}$dkim_signers
is set.

If I dump the memory of the invalid tree node I found one of the generated
X-Univie-DKIM-Headers. Either exactly the last one or shortly in front of the
last one.


(gdb) xxd 0x1a49c58 128
0000000: 582d 556e 6976 6965 2d44 4b49 4d2d 4368 X-Univie-DKIM-Ch
0000010: 6563 6b3a 2068 6561 6465 722e 693d 4030 eck: header.i=@0
0000020: 3037 676d 6169 6c2e 636f 6d20 6164 7370 07gmail.com adsp
0000030: 3a75 6e6b 6e6f 776e 2072 6573 756c 743a :unknown result:
0000040: 6e6f 6e65 200a 0000 f8de a401 0000 0000 none ...........

The other one points to the DKIM Result followed by the Header:
(gdb) xxd 0x1a76188 128
0000000: 6e6f 6e65 200a 0000 582d 556e 6976 6965 none ...X-Univie
0000010: 2d44 4b49 4d2d 4368 6563 6b3a 2068 6561 -DKIM-Check: hea
0000020: 6465 722e 693d 4069 6e74 6572 6e65 746f der.i=@interneto
0000030: 7779 6b61 6e74 6f72 2e70 6c20 6164 7370 wykantor.pl adsp
0000040: 3a75 6e6b 6e6f 776e 2072 6573 756c 743a :unknown result:
0000050: 6e6f 6e65 200a 0000 0000 0000 0000 0000 none ...........
0000060: 7a00 0000 4e00 0000 9061 a701 0000 0000 z...N....a......

at least on my production host I'm able to reproduce the segfault with:
-----
# exim -bh 185.111.183.29
< ehlo s29.globe-yellow-pages.com
< MAIL FROM:<33294114691-1-6402@???>
< RCPT TO:<service@localdomain>
< DATA
From: Datenbank =?UTF-8?B?R2VzY2jDpGZ0c2tvbnRha3Rl?=
<noreply@???>
To: service@localdomain
Subject: Neue Kunden - mehr Umsatz

test
.
-----

To-Addresses and Subject do not matter.

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