Bug#784112: Fwd: Bug#784112: /usr/sbin/saslauthd: saslauthd segfaults

Fri May 8 07:10:45 UTC 2015

On Wed, 6 May 2015 09:10:15 -0500 Dan White <dwhite at olp.net> wrote:

> Can you get a backtrace from the core dump, and debug output, e.g.:
>
> saslauthd -d -c -m /var/spool/postfix/

It does not seem that debug gives out any interesting information. Here are
the last lines from when the child processes died:

saslauthd[19194] :do_auth         : auth success: [user=thomas]
[service=imap] [realm=] [mech=shadow]
saslauthd[19194] :do_request      : response: OK
saslauthd[19195] :rel_accept_lock : released accept lock
saslauthd[19193] :get_accept_lock : acquired accept lock
saslauthd[19193] :rel_accept_lock : released accept lock
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19193] :do_auth         : auth failure: [user=noauth]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19193] :get_accept_lock : acquired accept lock
saslauthd[19194] :do_auth         : auth failure: [user=spam]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19193] :rel_accept_lock : released accept lock
saslauthd[19193] :do_auth         : auth failure: [user=test]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=info]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19193] :get_accept_lock : acquired accept lock
saslauthd[19193] :rel_accept_lock : released accept lock
saslauthd[19193] :do_auth         : auth failure: [user=admin]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=administrator]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19193] :get_accept_lock : acquired accept lock
saslauthd[19193] :rel_accept_lock : released accept lock
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=postmaster]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=sales]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=support]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=webmaster]
[service=smtp] [realm=] [mech=shadow] [reason=Incorrect password]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=help]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=contact]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=office]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock
saslauthd[19194] :do_auth         : auth failure: [user=staff]
[service=smtp] [realm=] [mech=shadow] [reason=Invalid username]
saslauthd[19194] :get_accept_lock : acquired accept lock
saslauthd[19194] :rel_accept_lock : released accept lock

The failed authentication attempts are certainly malicious software trying
out default credentials but they seem to be handled normally.

> This backend doesn't get used much these days. pam should functionally
> replace it. Does it also produce a segfault?

I will try this. I have shadow backend running for about 10 years now and
never had this urge to change it.

Thomas

On Wed, May 6, 2015 at 4:10 PM, Dan White <dwhite at olp.net> wrote:

> On 05/03/15 10:24 +0200, Thomas Kupka wrote:
>
>> Package: sasl2-bin
>> Version: 2.1.26.dfsg1-13
>> Severity: important
>> File: /usr/sbin/saslauthd
>>
>> Dear Maintainer,
>>
>> since upgrading to Jessie, all saslauthd processes segfault on a multiple
>> daily basis:
>>
>> May  3 06:26:12 mail kernel: [22739.740552] saslauthd[763]: segfault at 0
>> ip 00007faffd5d8c8a sp 00007ffda85ebe48 error 4 in libc-2.19.so
>> [7faffd557000+19f000]
>> May  3 06:26:12 mail kernel: [22739.928344] saslauthd[739]: segfault at 0
>> ip 00007faffd5d8c8a sp 00007ffda85ebe48 error 4 in libc-2.19.so
>> [7faffd557000+19f000]
>> May  3 06:26:12 mail kernel: [22740.127304] saslauthd[760]: segfault at 0
>> ip 00007faffd5d8c8a sp 00007ffda85ebe48 error 4 in libc-2.19.so
>> [7faffd557000+19f000]
>> May  3 10:04:24 mail kernel: [35831.420577] saslauthd[761]: segfault at 0
>> ip 00007faffd5d8c8a sp 00007ffda85ebe48 error 4 in libc-2.19.so
>> [7faffd557000+19f000]
>> May  3 10:04:24 mail kernel: [35831.607218] saslauthd[762]: segfault at 0
>> ip 00007faffd5d8c8a sp 00007ffda85ebe48 error 4 in libc-2.19.so
>> [7faffd557000+19f000]
>> May  3 10:04:24 mail postfix/smtpd[17269]: warning: SASL authentication
>> failure: cannot connect to saslauthd server: Connection refused
>>
>
> Can you get a backtrace from the core dump, and debug output, e.g.:
>
> saslauthd -d -c -m /var/spool/postfix/var/run/saslauthd -a shadow
>
> I can't reproduce your segfault on my unstable system running
> 2.1.26.dfsg1-13. However, I'm several version behind on some of the linked
> libraries.
>
>  -- Configuration Files:
>> /etc/default/saslauthd changed:
>> START=yes
>> DESC="SASL Authentication Daemon"
>> NAME="saslauthd"
>> MECHANISMS="shadow"
>>
>
> This backend doesn't get used much these days. pam should functionally
> replace it. Does it also produce a segfault?
>
> --
> Dan White
>
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