[Samba] 4.1.7, PAM and dlopen errors

[Jonathan Hunter]

Hi,

I upgraded to 4.1.7 from 4.1.4 last night; no other changes.

Now, every minute I am getting errors from cron as it tries to execute
a cron job (I'm not actually sure if the job fails or succeeds):

Jun 4 00:28:01 server crond[1080]: PAM adding faulty module:
/lib64/security/pam_winbind.so
Jun 4 00:28:01 server crond[1082]: PAM unable to
dlopen(/lib64/security/pam_winbind.so):
/usr/local/samba/lib/private/libwinbind-client.so: version
`SAMBA_4.1.7' not found (required by
/usr/local/samba/lib/libwbclient.so.0)
Jun 4 00:28:01 server crond[1082]: PAM adding faulty module:
/lib64/security/pam_winbind.so
Jun 4 00:28:01 server crond[1081]: PAM unable to
dlopen(/lib64/security/pam_winbind.so):
/usr/local/samba/lib/private/libwinbind-client.so: version
`SAMBA_4.1.7' not found (required by
/usr/local/samba/lib/libwbclient.so.0)
Jun 4 00:28:01 server crond[1081]: PAM adding faulty module:
/lib64/security/pam_winbind.so


Can anyone give me any pointers on how I might debug this? I am
running CentOS 6.5 and have upgraded samba numerous times before
without encountering this issue. selinux is disabled; and the
libraries do appear to be in the right place (from my limited
knowledge!). I also tried creating /etc/ld.so.conf.d/samba containing
the line "/usr/local/samba/lib" and running "ldconfig", but that
doesn't seem to have helped.

# ldconfig -v|grep winb
ldconfig: /etc/ld.so.conf.d/kernel-2.6.32-358.el6.x86_64.conf:6:
duplicate hwcap 1 nosegneg
ldconfig: /etc/ld.so.conf.d/kernel-2.6.32-431.3.1.el6.x86_64.conf:6:
duplicate hwcap 1 nosegneg
libnss_winbind.so -> libnss_winbind.so.2
libnss_winbind.so -> libnss_winbind.so.2
libwinbind-client.so -> libwinbind-client.so.0

and I have

lrwxrwxrwx 1 root root 44 Jan 21 02:30
/lib64/security/pam_winbind.so ->
/usr/local/samba/lib/security/pam_winbind.so
-rwxr-xr-x 1 root root 56133 Jun 2 18:53
/usr/local/samba/lib/security/pam_winbind.so
lrwxrwxrwx 1 root root 19 Jun 4 00:06
/usr/local/samba/lib/libwbclient.so -> libwbclient.so.0.11
lrwxrwxrwx 1 root root 19 Jun 4 00:06
/usr/local/samba/lib/libwbclient.so.0 -> libwbclient.so.0.11
-rwxr-xr-x 1 root root 63989 Jun 2 18:53
/usr/local/samba/lib/libwbclient.so.0.11
-rwxr-xr-x 1 root root 14832 Jun 2 18:53
/usr/local/samba/lib/private/libwinbind-client.so

Any pointers would be appreciated.

Thanks!

Jonathan

--
"If we knew what it was we were doing, it would not be called
research, would it?"
- Albert Einstein
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[steve]

On Wed, 2014-06-04 at 00:37 +0100, Jonathan Hunter wrote:
> Hi,
>
> I upgraded to 4.1.7 from 4.1.4 last night; no other changes.
>
> Now, every minute I am getting errors from cron as it tries to execute
> a cron job (I'm not actually sure if the job fails or succeeds):
>
> Jun 4 00:28:01 server crond[1080]: PAM adding faulty module:
> /lib64/security/pam_winbind.so

I think you need to update the links:
ln -s /usr/local/samba/lib/libnss_winbind.so /lib64
ln -s /lib64/libnss_winbind.so /lib64/libnss_winbind.so.2

and run:
ldconfig
again
Then link the new PAM module:
ln -s /usr/local/samba/lib/security/pam_winbind.so /lib64/security/
HTH
Steve

[Jonathan Hunter]

Thanks Steve, very much appreciated. Now resolved - see below :)

On 4 June 2014 11:33, steve <st...@steve-ss.com> wrote:
> On Wed, 2014-06-04 at 00:37 +0100, Jonathan Hunter wrote:
>>
>> Jun 4 00:28:01 server crond[1080]: PAM adding faulty module:
>> /lib64/security/pam_winbind.so
>
> I think you need to update the links:
> ln -s /usr/local/samba/lib/libnss_winbind.so /lib64
> ln -s /lib64/libnss_winbind.so /lib64/libnss_winbind.so.2

As far as I can see, these look OK - I have indeed set up the links
exactly like this. However, thank you for giving me the confidence
that this wasn't the issue - I'm glad to have been able to rule that
out.

I have now found the issue; I'm still not sure I 100% understand why
this was the case, but it turns out that crond, as it has been running
since the machine booted 143 days ago, had somehow got part of the
ldconfig cached - and was therefore not loading the modules correctly
as per the error messages I was seeing.

So, a simple 'service crond restart' has now fixed the issue - no
wonder I couldn't see anything wrong myself when testing from the
commandline.

Thanks very much for your help - at least this particular error
message (and solution) will now be available in the archives for
others experiencing the same problem!

Cheers,

Jonathan

--
"If we knew what it was we were doing, it would not be called
research, would it?"
- Albert Einstein