2019-01-30 13:25:57

by Russell Coker

[permalink] [raw]
Subject: strange systemd audit message

I'm seeing the following every time I login as sysadm_r, whether it's via /
bin/login or sshd. But the login works correctly anyway. Any suggestions for
what I should investigate?

type=PROCTITLE msg=audit(30/01/19 23:58:01.196:1595535) : proctitle=(systemd)
type=SYSCALL msg=audit(30/01/19 23:58:01.196:1595535) : arch=x86_64
syscall=execve success=no exit=EACCES(Permission denied) a0=0x55f2c3008780
a1=0x55f2c2fbe740 a2=0x55f2c302f1e0 a3=0x55f2c2e06010 items=0 ppid=1 pid=19802
auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root
fsgid=root tty=(none) ses=189 comm=(systemd) exe=/lib/systemd/systemd
subj=system_u:system_r:init_t:s0 key=(null)
type=AVC msg=audit(30/01/19 23:58:01.196:1595535) : avc: denied { transition
} for pid=19802 comm=(systemd) path=/lib/systemd/systemd dev="dm-0"
ino=3069920 scontext=system_u:system_r:init_t:s0
tcontext=root:sysadm_r:sysadm_t:s0 tclass=process permissive=0

--
My Main Blog http://etbe.coker.com.au/
My Documents Blog http://doc.coker.com.au/





2019-01-30 23:56:48

by Chris PeBenito

[permalink] [raw]
Subject: Re: strange systemd audit message

On 1/30/19 8:02 AM, Russell Coker wrote:
> I'm seeing the following every time I login as sysadm_r, whether it's via /
> bin/login or sshd. But the login works correctly anyway. Any suggestions for
> what I should investigate?
>
> type=PROCTITLE msg=audit(30/01/19 23:58:01.196:1595535) : proctitle=(systemd)
> type=SYSCALL msg=audit(30/01/19 23:58:01.196:1595535) : arch=x86_64
> syscall=execve success=no exit=EACCES(Permission denied) a0=0x55f2c3008780
> a1=0x55f2c2fbe740 a2=0x55f2c302f1e0 a3=0x55f2c2e06010 items=0 ppid=1 pid=19802
> auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root
> fsgid=root tty=(none) ses=189 comm=(systemd) exe=/lib/systemd/systemd
> subj=system_u:system_r:init_t:s0 key=(null)
> type=AVC msg=audit(30/01/19 23:58:01.196:1595535) : avc: denied { transition
> } for pid=19802 comm=(systemd) path=/lib/systemd/systemd dev="dm-0"
> ino=3069920 scontext=system_u:system_r:init_t:s0
> tcontext=root:sysadm_r:sysadm_t:s0 tclass=process permissive=0

I never login directly as sysadm, but now that I try, I see it too. I'm
unaware of why this is happening; I'd have to look at the code to try to
figure it out.

--
Chris PeBenito

2019-01-31 07:53:44

by Dominick Grift

[permalink] [raw]
Subject: Re: strange systemd audit message

Chris PeBenito <[email protected]> writes:

> On 1/30/19 8:02 AM, Russell Coker wrote:
>> I'm seeing the following every time I login as sysadm_r, whether it's via /
>> bin/login or sshd. But the login works correctly anyway. Any suggestions for
>> what I should investigate?
>>
>> type=PROCTITLE msg=audit(30/01/19 23:58:01.196:1595535) : proctitle=(systemd)
>> type=SYSCALL msg=audit(30/01/19 23:58:01.196:1595535) : arch=x86_64
>> syscall=execve success=no exit=EACCES(Permission denied) a0=0x55f2c3008780
>> a1=0x55f2c2fbe740 a2=0x55f2c302f1e0 a3=0x55f2c2e06010 items=0 ppid=1 pid=19802
>> auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root
>> fsgid=root tty=(none) ses=189 comm=(systemd) exe=/lib/systemd/systemd
>> subj=system_u:system_r:init_t:s0 key=(null)
>> type=AVC msg=audit(30/01/19 23:58:01.196:1595535) : avc: denied { transition
>> } for pid=19802 comm=(systemd) path=/lib/systemd/systemd dev="dm-0"
>> ino=3069920 scontext=system_u:system_r:init_t:s0
>> tcontext=root:sysadm_r:sysadm_t:s0 tclass=process permissive=0
>
> I never login directly as sysadm, but now that I try, I see it too.
> I'm unaware of why this is happening; I'd have to look at the code to
> try to figure it out.

I think its the systemd --user instance spawned by systemd --system on
behalf of root. Basically systemd --system pam code reads /etc/pam.d/systemd-user which calls pam_selinux
and then ends up interpretting either failsafe_context or default_contexts

Just a guess though. Baasically it boils down to not having support
for systemd --user functionality in the policy.

--
Key fingerprint = 5F4D 3CDB D3F8 3652 FBD8 02D5 3B6C 5F1D 2C7B 6B02
https://sks-keyservers.net/pks/lookup?op=get&search=0x3B6C5F1D2C7B6B02
Dominick Grift