What's the best way to debug SELinux issues on SSSD?

[Fabiano Fidêncio]

People,

I've been trying to debug a SELinux issue related to the domain
resolution order.

Basically, if there's no domain_reoslution_order set:
[root@client1 vagrant]# ssh -l admin localhost
Password:
Last login: Mon May 21 19:00:06 2018 from ::1
[admin@client1 ~]$ id -Z
staff_u:staff_r:staff_t:s0-s0:c0.c1023

But, if domain_resolution_order is set:
[root@client1 vagrant]# ssh -l admin localhost
Password:
Last login: Mon May 21 19:30:45 2018 from ::1
[[e-mail](a)client1 ~]$ id -Z
unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023

First thing that came to my mind was to take a look at
selinux_child.logs, but it didn't give me any clue as the logs are
exactly the same for both cases:

No domain_resolution_order set:
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
(0x0400): selinux_child started.
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
(0x2000): Running with effective IDs: [0][0].
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
(0x2000): Running with real IDs [0][0].
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
(0x0400): context initialized
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
[unpack_buffer] (0x2000): seuser length: 7
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
[unpack_buffer] (0x2000): seuser: staff_u
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
[unpack_buffer] (0x2000): mls_range length: 14
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
[unpack_buffer] (0x2000): mls_range: s0-s0:c0.c1023
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
[unpack_buffer] (0x2000): username length: 5
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
[unpack_buffer] (0x2000): username: admin
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
(0x0400): performing selinux operations
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
[seuser_needs_update] (0x2000): getseuserbyname: ret: 0 seuser:
staff_u mls: s0-s0:c0.c1023
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
[pack_buffer] (0x0400): result [0]
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
[prepare_response] (0x4000): r->size: 4
(Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
(0x0400): selinux_child completed successfully

domain_resolution_order set:
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
(0x0400): selinux_child started.
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
(0x2000): Running with effective IDs: [0][0].
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
(0x2000): Running with real IDs [0][0].
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
(0x0400): context initialized
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
[unpack_buffer] (0x2000): seuser length: 7
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
[unpack_buffer] (0x2000): seuser: staff_u
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
[unpack_buffer] (0x2000): mls_range length: 14
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
[unpack_buffer] (0x2000): mls_range: s0-s0:c0.c1023
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
[unpack_buffer] (0x2000): username length: 5
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
[unpack_buffer] (0x2000): username: admin
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
(0x0400): performing selinux operations
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
[seuser_needs_update] (0x2000): getseuserbyname: ret: 0 seuser:
staff_u mls: s0-s0:c0.c1023
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
[pack_buffer] (0x0400): result [0]
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
[prepare_response] (0x4000): r->size: 4
(Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
(0x0400): selinux_child completed successfully

Taking a look at the IPA provider, logs also do like the very same:
https://paste.fedoraproject.org/paste/FKhvxyj3clzXuE5C7tMGhw (pastebin
is huge!)

Some tip on which logs I could take a look and/or part of the code I
could instrument in order to, at least, get some directions?

Thanks in advance,
--
Fabiano Fidêncio

[Jakub Hrozek]

>  On 21 May 2018, at 21:39, Fabiano Fidêncio
> <fidencio(a)redhat.com&gt; wrote:
>  
>  People,
>  
>  I've been trying to debug a SELinux issue related to the domain
>  resolution order.
>  
>  Basically, if there's no domain_reoslution_order set:
>  [root@client1 vagrant]# ssh -l admin localhost
>  Password:
>  Last login: Mon May 21 19:00:06 2018 from ::1
>  [admin@client1 ~]$ id -Z
>  staff_u:staff_r:staff_t:s0-s0:c0.c1023
>  
>  But, if domain_resolution_order is set:
>  [root@client1 vagrant]# ssh -l admin localhost
>  Password:
>  Last login: Mon May 21 19:30:45 2018 from ::1
>  [[e-mail](a)client1 ~]$ id -Z
>  unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 
Since sssd calls into libsemanage, then I would start with looking at the output of
“semanage login -l”. Is the context after selinux_child runs to completion set for admin
or admin(a)ipa.example? Maybe libsemanage canonicalizes the name or UID with getpnam/uid and
therefore uses the qualified name but because the provider has no sense of the
domain_resolution_order, it calls sss_set_seuser() with the shortname?

Looking at whether we call sss_set_seuser() with the correct parameters might give some
hint as well.

>  
>  First thing that came to my mind was to take a look at
>  selinux_child.logs, but it didn't give me any clue as the logs are
>  exactly the same for both cases:
>  
>  No domain_resolution_order set:
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>  (0x0400): selinux_child started.
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>  (0x2000): Running with effective IDs: [0][0].
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>  (0x2000): Running with real IDs [0][0].
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>  (0x0400): context initialized
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>  [unpack_buffer] (0x2000): seuser length: 7
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>  [unpack_buffer] (0x2000): seuser: staff_u
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>  [unpack_buffer] (0x2000): mls_range length: 14
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>  [unpack_buffer] (0x2000): mls_range: s0-s0:c0.c1023
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>  [unpack_buffer] (0x2000): username length: 5
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>  [unpack_buffer] (0x2000): username: admin
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>  (0x0400): performing selinux operations
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>  [seuser_needs_update] (0x2000): getseuserbyname: ret: 0 seuser:
>  staff_u mls: s0-s0:c0.c1023
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>  [pack_buffer] (0x0400): result [0]
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>  [prepare_response] (0x4000): r->size: 4
>  (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>  (0x0400): selinux_child completed successfully
>  
>  domain_resolution_order set:
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>  (0x0400): selinux_child started.
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>  (0x2000): Running with effective IDs: [0][0].
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>  (0x2000): Running with real IDs [0][0].
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>  (0x0400): context initialized
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>  [unpack_buffer] (0x2000): seuser length: 7
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>  [unpack_buffer] (0x2000): seuser: staff_u
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>  [unpack_buffer] (0x2000): mls_range length: 14
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>  [unpack_buffer] (0x2000): mls_range: s0-s0:c0.c1023
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>  [unpack_buffer] (0x2000): username length: 5
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>  [unpack_buffer] (0x2000): username: admin
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>  (0x0400): performing selinux operations
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>  [seuser_needs_update] (0x2000): getseuserbyname: ret: 0 seuser:
>  staff_u mls: s0-s0:c0.c1023
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>  [pack_buffer] (0x0400): result [0]
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>  [prepare_response] (0x4000): r->size: 4
>  (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>  (0x0400): selinux_child completed successfully
>  
>  Taking a look at the IPA provider, logs also do like the very same:
>  https://paste.fedoraproject.org/paste/FKhvxyj3clzXuE5C7tMGhw (pastebin
>  is huge!)
>  
>  Some tip on which logs I could take a look and/or part of the code I
>  could instrument in order to, at least, get some directions?
>  
>  Thanks in advance,
>  --
>  Fabiano Fidêncio
>  _______________________________________________
>  sssd-devel mailing list -- sssd-devel(a)lists.fedorahosted.org
>  To unsubscribe send an email to sssd-devel-leave(a)lists.fedorahosted.org
>  Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html
>  List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
>  List Archives:
> https://lists.fedoraproject.org/archives/list/[e-mail]...

[Fabiano Fidêncio]

On Mon, May 21, 2018 at 10:32 PM, Jakub Hrozek <jhrozek(a)redhat.com&gt; wrote:
> > On 21 May 2018, at 21:39, Fabiano Fidêncio <fidencio(a)redhat.com&gt; wrote:
> >
> > People,
> >
> > I've been trying to debug a SELinux issue related to the domain
> > resolution order.
> >
> > Basically, if there's no domain_reoslution_order set:
> > [root@client1 vagrant]# ssh -l admin localhost
> > Password:
> > Last login: Mon May 21 19:00:06 2018 from ::1
> > [admin@client1 ~]$ id -Z
> > staff_u:staff_r:staff_t:s0-s0:c0.c1023
> >
> > But, if domain_resolution_order is set:
> > [root@client1 vagrant]# ssh -l admin localhost
> > Password:
> > Last login: Mon May 21 19:30:45 2018 from ::1
> > [[e-mail](a)client1 ~]$ id -Z
> > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
>
>  Since sssd calls into libsemanage, then I would start with looking at the output of
> “semanage login -l”. 
You gave me this tip before, I did test it but I forgot to add details
about it :-/

The output is basically the same with or without domain_resolution_order set:

[root@client1 x86_64]# cat /etc/sssd/sssd.conf | grep domain_resolution_order
domain_resolution_order = foo
[root@client1 x86_64]# systemctl restart sssd
[root@client1 x86_64]# semanage login -l

Login Name           SELinux User         MLS/MCS Range        Service

__default__          unconfined_u         s0-s0:c0.c1023       *
admin                staff_u              s0-s0:c0.c1023       *
root                 unconfined_u         s0-s0:c0.c1023       *


[root@client1 x86_64]# vim /etc/sssd/sssd.conf
[root@client1 x86_64]# cat /etc/sssd/sssd.conf | grep domain_resolution_order
#domain_resolution_order = foo
[root@client1 x86_64]# systemctl restart sssd
[root@client1 x86_64]# semanage login -l

Login Name           SELinux User         MLS/MCS Range        Service

__default__          unconfined_u         s0-s0:c0.c1023       *
admin                staff_u              s0-s0:c0.c1023       *
root                 unconfined_u         s0-s0:c0.c1023       *


>  Is the context after selinux_child runs to completion set for admin
> or admin(a)ipa.example? 
In the selinux_child.log I can only see:
[[sssd[selinux_child[18149]]]] [unpack_buffer] (0x2000): username: admin

And it happens for both cases, with or without domain_resolution_order
being used.

>  Maybe libsemanage canonicalizes the name or UID with getpnam/uid and
> therefore uses the qualified name but because the provider has no sense of the
> domain_resolution_order, it calls sss_set_seuser() with the shortname? 
That's a good question. sss_set_seuser() hasn't been called, at all.

>
> Looking at whether we call sss_set_seuser() with the correct parameters might give
some hint as well.
>
>>
>> First thing that came to my mind was to take a look at
>> selinux_child.logs, but it didn't give me any clue as the logs are
>> exactly the same for both cases:
>>
>> No domain_resolution_order set:
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>> (0x0400): selinux_child started.
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>> (0x2000): Running with effective IDs: [0][0].
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>> (0x2000): Running with real IDs [0][0].
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>> (0x0400): context initialized
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>> [unpack_buffer] (0x2000): seuser length: 7
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>> [unpack_buffer] (0x2000): seuser: staff_u
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>> [unpack_buffer] (0x2000): mls_range length: 14
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>> [unpack_buffer] (0x2000): mls_range: s0-s0:c0.c1023
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>> [unpack_buffer] (0x2000): username length: 5
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>> [unpack_buffer] (0x2000): username: admin
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>> (0x0400): performing selinux operations
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>> [seuser_needs_update] (0x2000): getseuserbyname: ret: 0 seuser:
>> staff_u mls: s0-s0:c0.c1023
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>> [pack_buffer] (0x0400): result [0]
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
>> [prepare_response] (0x4000): r->size: 4
>> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
>> (0x0400): selinux_child completed successfully
>>
>> domain_resolution_order set:
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>> (0x0400): selinux_child started.
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>> (0x2000): Running with effective IDs: [0][0].
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>> (0x2000): Running with real IDs [0][0].
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>> (0x0400): context initialized
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>> [unpack_buffer] (0x2000): seuser length: 7
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>> [unpack_buffer] (0x2000): seuser: staff_u
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>> [unpack_buffer] (0x2000): mls_range length: 14
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>> [unpack_buffer] (0x2000): mls_range: s0-s0:c0.c1023
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>> [unpack_buffer] (0x2000): username length: 5
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>> [unpack_buffer] (0x2000): username: admin
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>> (0x0400): performing selinux operations
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>> [seuser_needs_update] (0x2000): getseuserbyname: ret: 0 seuser:
>> staff_u mls: s0-s0:c0.c1023
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>> [pack_buffer] (0x0400): result [0]
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
>> [prepare_response] (0x4000): r->size: 4
>> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
>> (0x0400): selinux_child completed successfully
>>
>> Taking a look at the IPA provider, logs also do like the very same:
>> https://paste.fedoraproject.org/paste/FKhvxyj3clzXuE5C7tMGhw (pastebin
>> is huge!)
>>
>> Some tip on which logs I could take a look and/or part of the code I
>> could instrument in order to, at least, get some directions?
>>
>> Thanks in advance,
>> --
>> Fabiano Fidêncio
>> _______________________________________________
>> sssd-devel mailing list -- sssd-devel(a)lists.fedorahosted.org
>> To unsubscribe send an email to sssd-devel-leave(a)lists.fedorahosted.org
>> Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html
>> List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
>> List Archives:
https://lists.fedoraproject.org/archives/list/[e-mail]...
> _______________________________________________
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> List Archives:
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[Jakub Hrozek]

>  On 21 May 2018, at 23:58, Fabiano Fidêncio
> <fidencio(a)redhat.com&gt; wrote:
>  
>  On Mon, May 21, 2018 at 10:32 PM, Jakub Hrozek <jhrozek(a)redhat.com&gt; wrote:
> > 
> > 
> >> On 21 May 2018, at 21:39, Fabiano Fidêncio <fidencio(a)redhat.com&gt; wrote:
> >> 
> >> People,
> >> 
> >> I've been trying to debug a SELinux issue related to the domain
> >> resolution order.
> >> 
> >> Basically, if there's no domain_reoslution_order set:
> >> [root@client1 vagrant]# ssh -l admin localhost
> >> Password:
> >> Last login: Mon May 21 19:00:06 2018 from ::1
> >> [admin@client1 ~]$ id -Z
> >> staff_u:staff_r:staff_t:s0-s0:c0.c1023
> >> 
> >> But, if domain_resolution_order is set:
> >> [root@client1 vagrant]# ssh -l admin localhost
> >> Password:
> >> Last login: Mon May 21 19:30:45 2018 from ::1
> >> [[e-mail](a)client1 ~]$ id -Z
> >> unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
> > 
> > Since sssd calls into libsemanage, then I would start with looking at the output of
> “semanage login -l”.
>  
>  You gave me this tip before, I did test it but I forgot to add details
>  about it :-/
>  
>  The output is basically the same with or without domain_resolution_order set:
>  
>  [root@client1 x86_64]# cat /etc/sssd/sssd.conf | grep domain_resolution_order
>  domain_resolution_order = foo
>  [root@client1 x86_64]# systemctl restart sssd
>  [root@client1 x86_64]# semanage login -l
>  
>  Login Name           SELinux User         MLS/MCS Range        Service
>  
>  __default__          unconfined_u         s0-s0:c0.c1023       *
>  admin                staff_u              s0-s0:c0.c1023       *
>  root                 unconfined_u         s0-s0:c0.c1023       *
>  
>  
>  [root@client1 x86_64]# vim /etc/sssd/sssd.conf
>  [root@client1 x86_64]# cat /etc/sssd/sssd.conf | grep domain_resolution_order
>  #domain_resolution_order = foo
>  [root@client1 x86_64]# systemctl restart sssd
>  [root@client1 x86_64]# semanage login -l
>  
>  Login Name           SELinux User         MLS/MCS Range        Service
>  
>  __default__          unconfined_u         s0-s0:c0.c1023       *
>  admin                staff_u              s0-s0:c0.c1023       *
>  root                 unconfined_u         s0-s0:c0.c1023       *
>  
>  
> > Is the context after selinux_child runs to completion set for admin or
> admin(a)ipa.example?
>  
>  In the selinux_child.log I can only see:
>  [[sssd[selinux_child[18149]]]] [unpack_buffer] (0x2000): username: admin 
Right and looking at the selinux_child code, we /try/ to format the name to the output
format that getpwnam would return for precisely this reason (see selinux_child_setup). but
because we don’t know about the extra qualification that the domain suffix causes, we fail
to qualify the name.

And looking at the pam_selinux code, it does canonicalize the username with getpwnam:

496   if (!(username = get_item(pamh, PAM_USER))) {
497     pam_syslog(pamh, LOG_ERR, "Cannot obtain the user name");
498     return PAM_USER_UNKNOWN;
499   }
500
501   if ((pwd = pam_modutil_getpwnam(pamh, username)) != NULL) {
502     username = pwd->pw_name;
503   } /* ignore error and keep using original username */
504

So selinux_child sets the context to admin, but pam_selinux checks the context of
admin@domain because that’s what getpwnam(“admin”) returns.

>  
>  And it happens for both cases, with or without domain_resolution_order
>  being used.
>  
> > Maybe libsemanage canonicalizes the name or UID with getpnam/uid and therefore uses
> the qualified name but because the provider has no sense of the domain_resolution_order,
> it calls sss_set_seuser() with the shortname?
>  
>  That's a good question. sss_set_seuser() hasn't been called, at all. 
There is an optimization that first queries the semanage back end and if the context is
already set, then sss_set_seuser() is just skipped. Setting the context is not/was not a
cheap operation.

>  
> > 
> > Looking at whether we call sss_set_seuser() with the correct parameters might give
> some hint as well.
> > 
> >> 
> >> First thing that came to my mind was to take a look at
> >> selinux_child.logs, but it didn't give me any clue as the logs are
> >> exactly the same for both cases:
> >> 
> >> No domain_resolution_order set:
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
> >> (0x0400): selinux_child started.
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
> >> (0x2000): Running with effective IDs: [0][0].
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
> >> (0x2000): Running with real IDs [0][0].
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
> >> (0x0400): context initialized
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
> >> [unpack_buffer] (0x2000): seuser length: 7
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
> >> [unpack_buffer] (0x2000): seuser: staff_u
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
> >> [unpack_buffer] (0x2000): mls_range length: 14
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
> >> [unpack_buffer] (0x2000): mls_range: s0-s0:c0.c1023
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
> >> [unpack_buffer] (0x2000): username length: 5
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
> >> [unpack_buffer] (0x2000): username: admin
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
> >> (0x0400): performing selinux operations
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
> >> [seuser_needs_update] (0x2000): getseuserbyname: ret: 0 seuser:
> >> staff_u mls: s0-s0:c0.c1023
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
> >> [pack_buffer] (0x0400): result [0]
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]]
> >> [prepare_response] (0x4000): r->size: 4
> >> (Mon May 21 19:30:44 2018) [[sssd[selinux_child[23351]]]] [main]
> >> (0x0400): selinux_child completed successfully
> >> 
> >> domain_resolution_order set:
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
> >> (0x0400): selinux_child started.
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
> >> (0x2000): Running with effective IDs: [0][0].
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
> >> (0x2000): Running with real IDs [0][0].
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
> >> (0x0400): context initialized
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
> >> [unpack_buffer] (0x2000): seuser length: 7
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
> >> [unpack_buffer] (0x2000): seuser: staff_u
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
> >> [unpack_buffer] (0x2000): mls_range length: 14
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
> >> [unpack_buffer] (0x2000): mls_range: s0-s0:c0.c1023
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
> >> [unpack_buffer] (0x2000): username length: 5
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
> >> [unpack_buffer] (0x2000): username: admin
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
> >> (0x0400): performing selinux operations
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
> >> [seuser_needs_update] (0x2000): getseuserbyname: ret: 0 seuser:
> >> staff_u mls: s0-s0:c0.c1023
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
> >> [pack_buffer] (0x0400): result [0]
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]]
> >> [prepare_response] (0x4000): r->size: 4
> >> (Mon May 21 19:31:36 2018) [[sssd[selinux_child[23398]]]] [main]
> >> (0x0400): selinux_child completed successfully
> >> 
> >> Taking a look at the IPA provider, logs also do like the very same:
> >> https://paste.fedoraproject.org/paste/FKhvxyj3clzXuE5C7tMGhw (pastebin
> >> is huge!)
> >> 
> >> Some tip on which logs I could take a look and/or part of the code I
> >> could instrument in order to, at least, get some directions?
> >> 
> >> Thanks in advance,
> >> --
> >> Fabiano Fidêncio
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