#1051003 libgdbm6: trap divide error in libgdbm.so.6.0.0

Package:
libgdbm6
Source:
libgdbm6
Description:
GNU dbm database routines (runtime version)
Submitter:
Schnitzi
Date:
2026-02-20 21:35:02 UTC
Severity:
normal
#1051003#5
Date:
2023-09-01 09:13:22 UTC
From:
To:
Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?
We are authenticating dovecot users via PAM. Our PAM-Setup includes pam_shield. pam_shield uses libgdbm6.
As soon as pam_shield is triggered (meaning it blocks an IP) we get a trap divide error.
Details see below

   * What exactly did you do (or not do) that was effective (or
     ineffective)?
When removing pam_shield from our PAM-Setup the problem disappears

   * What was the outcome of this action?
   * What outcome did you expect instead?
Just works.

Journal-Output:
Aug 31 18:02:34 xyz dovecot[2451]: auth: Error: auth-worker: Aborted PASSV request for xyz@xyz.xyz: Worker process died unexpectedly
Aug 31 18:02:34 xyz dovecot[2451]: auth-worker: Fatal: master: service(auth-worker): child 118182 killed with signal 8
Aug 31 18:02:34 xyz kernel: traps: auth[118182] trap divide error ip:7f7366d16f06 sp:7ffc44386580 error:0 in libgdbm.so.6.0.0[7f7366d12000+a000]

PAM-Setup:
auth required pam_abl.so config=/etc/security/pam_abl.conf
auth sufficient pam_mysql.so list-of-options-remoed
auth required pam_shield.so
auth required pam_deny.so


*** End of the template - remove these template lines ***
#1051003#10
Date:
2023-09-02 23:46:59 UTC
From:
To:
Hello,

I don't know if the problem comes from gdbm or pam_shield yet. The
pam_shield package, although orphaned, could be updated. The original
pam-shield repository is archived [1], but there seems to be a more
recent fork [2].

Could you test with h0tw1r3's 0.9.7 release [3] if the problem persist?
If this fixes the problem, then updating pam-shield package would fix
this issue.

/Nicolas

[1] https://github.com/jtniehof/pam_shield
[2] https://github.com/h0tw1r3/pam_shield
[3] https://github.com/h0tw1r3/pam_shield/releases/tag/0.9.7
#1051003#15
Date:
2023-09-04 08:09:23 UTC
From:
To:
Hi,

PAM-shield uses a database file that I migrated from debian 10 to debian
12 in one big double upgrade.
For testing purposes I deleted that database file, created an empty file
instead and the trap divide error disappeared. PAM-shield works fine
again as well and has been for three days now.

So... problem solved for my case.

Is this problem still relevant for libgdbm as we have a trap divide
error that should not happen no matter what? Or should I open a ticket
at libpam-shield so the problem (and the solution) is documented - even
if the package is orphaned?

Thanks for your support!

Schnitzi
#1051003#20
Date:
2023-09-04 17:55:51 UTC
From:
To:
Hello Christopher,

Le 2023-09-04 à 04 h 09, Christopher Voglstätter a écrit :
It's a good and a bad news at the same time. A good news because you
found a working workaround, and a bad news because since a database
reset works, it should mean a problem in gdbm itself during some kind of
upgrades.

I don't know if we can go further with this, but did you keep the old
database file? So one could try to reproduce the problem, and if so,
forward it upstream.

/Nicolas
#1051003#25
Date:
2023-11-06 15:09:59 UTC
From:
To:
Hello,
Any update on this development?

/Nicolas