From:   Dominick Grift <dac.override@gmail.com>
To:     "Sugar\, David" <dsugar@tresys.com>
Cc:     Chris PeBenito <pebenito@ieee.org>,
        "selinux-refpolicy\@vger.kernel.org" 
        <selinux-refpolicy@vger.kernel.org>
Subject: Re: [PATCH] Resolve some denials related to sending journal messages
References: <20190404122900.8945-1-dsugar@tresys.com>
        <20190404122900.8945-2-dsugar@tresys.com>
        <48f4a705-36e6-aca7-15e4-1c100785aaf8@ieee.org>
        <5898f8be-d46d-1bbd-de56-d59316c1ee16@tresys.com>
Date:   Mon, 08 Apr 2019 15:41:53 +0200
In-Reply-To: <5898f8be-d46d-1bbd-de56-d59316c1ee16@tresys.com> (David Sugar's
        message of "Mon, 8 Apr 2019 13:33:42 +0000")
Message-ID: <87v9zok40u.fsf@gmail.com>
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"Sugar, David" <dsugar@tresys.com> writes:


> On 4/7/19 8:52 PM, Chris PeBenito wrote:
>> On 4/4/19 8:29 AM, Sugar, David wrote:
>>> type=3DAVC msg=3Daudit(1554324562.840:159): avc:=C2=A0 denied=C2=A0 { s=
endto } for=C2=A0=20
>>> pid=3D7277 comm=3D"systemd-backlig" path=3D"/run/systemd/journal/socket=
"=20
>>> scontext=3Dsystem_u:system_r:systemd_backlight_t:s0=20
>>> tcontext=3Dsystem_u:system_r:kernel_t:s0 tclass=3Dunix_dgram_socket=20
>>> permissive=3D1
>>> type=3DAVC msg=3Daudit(1554324271.863:245): avc:=C2=A0 denied=C2=A0 { s=
endto } for=C2=A0=20
>>> pid=3D7421 comm=3D"systemd-user-se" path=3D"/run/systemd/journal/socket=
"=20
>>> scontext=3Dsystem_u:system_r:systemd_sessions_t:s0=20
>>> tcontext=3Dsystem_u:system_r:kernel_t:s0 tclass=3Dunix_dgram_socket=20
>>> permissive=3D0
>>> type=3DAVC msg=3Daudit(1554324635.844:313): avc:=C2=A0 denied=C2=A0 { s=
endto } for=C2=A0=20
>>> pid=3D7744 comm=3D"systemd-cryptse" path=3D"/run/systemd/journal/socket=
"=20
>>> scontext=3Dsystem_u:system_r:lvm_t:s0=20
>>> tcontext=3Dsystem_u:system_r:kernel_t:s0 tclass=3Dunix_dgram_socket=20
>>> permissive=3D1
>>
>> I think we've reached the limit of the explicit kernel_dgram_send()=20
>> and it's time to reevaluate putting this in logging_send_syslog_msg().
>>
> That makes sense.=C2=A0 I will submit a patch after I test a bit.=C2=A0 B=
ut it=20
> looks like everywhere (except the systemd module) that uses=20
> kernel_dgram_send() already has logging_send_syslog_msg() so once=20
> kernel_dgram_send() is added to logging_send_syslog_msg(),=20
> kernel_dgram_send() can removed from those domains.
>
> The exceptions are:
>
> 1) In the systemd module there isn't much use of=20
> logging_send_syslog_msg().=C2=A0 For this case I will add=20
> logging_send_syslog_msg() as required.

see:

https://github.com/SELinuxProject/refpolicy/blob/master/policy/modules/syst=
em/systemd.te#L410

So "systemd_log_parse_environment()" implies "logging_send_syslog_msg()"

>
> 2) In the interface init_daemon_domain(), it uses kernel_dgram_send()=20
> directly, there it probably doesn't need to use=20
> logging_send_syslog_msg(). This may be able to go away as modules might=20
> already use logging now, I will try removing and see what breaks.
>
>>
>>> Signed-off-by: Dave Sugar <dsugar@tresys.com>
>>> ---
>>> =C2=A0 policy/modules/system/lvm.te=C2=A0=C2=A0=C2=A0=C2=A0 | 1 +
>>> =C2=A0 policy/modules/system/systemd.te | 4 ++++
>>> =C2=A0 2 files changed, 5 insertions(+)
>>>
>>> diff --git a/policy/modules/system/lvm.te b/policy/modules/system/lvm.te
>>> index ec3b4a18..aea199d4 100644
>>> --- a/policy/modules/system/lvm.te
>>> +++ b/policy/modules/system/lvm.te
>>> @@ -222,6 +222,7 @@ filetrans_pattern(lvm_t, lvm_etc_t,=20
>>> lvm_metadata_t, file)
>>> =C2=A0 files_etc_filetrans(lvm_t, lvm_metadata_t, file)
>>> =C2=A0 files_search_mnt(lvm_t)
>>> =C2=A0 +kernel_dgram_send(lvm_t)
>>> =C2=A0 kernel_request_load_module(lvm_t)
>>> =C2=A0 kernel_get_sysvipc_info(lvm_t)
>>> =C2=A0 kernel_read_system_state(lvm_t)
>>> diff --git a/policy/modules/system/systemd.te=20
>>> b/policy/modules/system/systemd.te
>>> index f6455f6f..541117a9 100644
>>> --- a/policy/modules/system/systemd.te
>>> +++ b/policy/modules/system/systemd.te
>>> @@ -228,6 +228,8 @@ dev_rw_sysfs(systemd_backlight_t)
>>> =C2=A0 # for udev.conf
>>> =C2=A0 files_read_etc_files(systemd_backlight_t)
>>> =C2=A0 +kernel_dgram_send(systemd_backlight_t)
>>> +
>>> =C2=A0 # for /run/udev/data/+backlight*
>>> =C2=A0 udev_read_pid_files(systemd_backlight_t)
>>> =C2=A0 @@ -981,6 +983,8 @@ allow systemd_sessions_t self:process setfsc=
reate;
>>> =C2=A0 allow systemd_sessions_t systemd_sessions_var_run_t:file=20
>>> manage_file_perms;
>>> =C2=A0 files_pid_filetrans(systemd_sessions_t, systemd_sessions_var_run=
_t,=20
>>> file)
>>> =C2=A0 +kernel_dgram_send(systemd_sessions_t)
>>> +
>>> =C2=A0 selinux_get_enforce_mode(systemd_sessions_t)
>>> =C2=A0 selinux_get_fs_mount(systemd_sessions_t)
>>>
>>
>>

--=20
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Dominick Grift