[PATCH 1/1] Smack:- Fix the issue of wrong info printed in ptrace error logs

[Vishal Goel]

>>>>> Currently tracer process info is printed in object field in
>>>>> smack error log for ptrace check which is wrong.
>>>>> Object process should print the tracee process info.
>>>>> Tracee info is not printed in the smack error logs.
>>>>> So it is not possible to debug the ptrace smack issues.
>>>>>
>>>>> Now changes has been done to print both tracer and tracee
>>>>> process info in smack error logs for ptrace scenarios
>>>>>
>>>>> Old logs:-
>>>>> [  378.098330] audit: type=1400 audit(1637212273.300:2): lsm=SMACK fn=smack_ptrace_access_check action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= pid=9397 comm="tst_pt" opid=9397 ocomm="tst_pt"
>>>>> [  520.261605] audit: type=1400 audit(1637212415.464:3): lsm=SMACK fn=smack_ptrace_traceme action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= pid=12685 comm="tst_pt_me" opid=12563 ocomm="bash"
>>>>> [ 1445.259319] audit: type=1400 audit(1637213340.460:5): lsm=SMACK fn=smack_bprm_set_creds action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= pid=1778 comm="tst_bprm" opid=1776 ocomm="tst_bprm"
>>>>>
>>>>> New logs:-
>>>>> [  378.098330] audit: type=1400 audit(1637212273.300:2): lsm=SMACK fn=smack_ptrace_access_check action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= tracer-pid=5189 tracer-comm="tst_pt" pid=5189 comm="tst_pt" tracee-pid=962 tracee-comm="test_tracee"
>>>>> [  520.261605] audit: type=1400 audit(1637212415.464:3): lsm=SMACK fn=smack_ptrace_traceme action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= tracer-pid=6161 tracer-comm="bash" pid=6310 comm="tst_pt_me" tracee-pid=6310 tracee-comm="tst_pt_me"
>>>>> [ 1445.259319] audit: type=1400 audit(1637213340.460:5): lsm=SMACK fn=smack_bprm_set_creds action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= tracer-pid=6435 tracer-comm="tst_bprm" pid=6436 comm="tst_bprm" tracee-pid=6436 tracee-comm="tst_bprm"
>>>>>
>>>>> Signed-off-by: Vishal Goel <vishal.goel at samsung.com>
>>>>
>>>> Does anyone from the audit side object to my taking this
>>>> in the Smack tree?
>>
>>> The audit subsystem already has the "opid" and "ocomm" fields for
>>> reporting on the object task info and this is even available in
>>> dump_common_audit_data() via LSM_AUDIT_DATA_TASK; is there a reason
>>> that can't be used instead?
>>
>> That info is not sufficient for debugging smack issues in ptrace calls.
>> Tracee information is not printed in the logs. For eg. in below log-
>> [  378.098330] audit: type=1400 audit(1637212273.300:2): lsm=SMACK fn=smack_ptrace_access_check action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= pid=9397 comm="tst_pt" opid=9397 ocomm="tst_pt"
>>
>> There is no information of the tracee process.
>> So to debug such ptrace issues, both tracer and tracee information is needed.
>> That's why added new type to print both info specifically for ptrace scenarios.
 

> From what I saw you are trying to record information about the tracer
> and the tracee, yes?  The "pid", "comm", "opid", and "ocomm" fields
> should be used instead of adding new fields.

Actually in smack_ptrace_access_check() function, tracer process is current process.
While some other process is object process(tracee).
But in case of smack_ptrace_traceme() function, tracer process is parent process.
While current process is object process(tracee). So in this case, both pid/comm
and opid/ocomm will print current process info only i.e tracess process.
So tracer process info is not getting printed.
Similarly for smack_bprm_creds_for_exec(), tracer process is parent process.
And current process is tracee process.
So that's why we need to print separately tracer and tracee process info
without any confusion.
 
--------- Original Message ---------
Sender : Paul Moore <paul at paul-moore.com>
Date : 2022-02-01 23:05 (GMT+9)
Title : Re: Re: [PATCH 1/1] Smack:- Fix the issue of wrong info printed in ptrace error logs
 
On Tue, Feb 1, 2022 at 2:55 AM Vishal Goel <vishal.goel at samsung.com> wrote:
> >>> Currently tracer process info is printed in object field in
> >>> smack error log for ptrace check which is wrong.
> >>> Object process should print the tracee process info.
> >>> Tracee info is not printed in the smack error logs.
> >>> So it is not possible to debug the ptrace smack issues.
> >>>
> >>> Now changes has been done to print both tracer and tracee
> >>> process info in smack error logs for ptrace scenarios
> >>>
> >>> Old logs:-
> >>> [  378.098330] audit: type=1400 audit(1637212273.300:2): lsm=SMACK fn=smack_ptrace_access_check action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= pid=9397 comm="tst_pt" opid=9397 ocomm="tst_pt"
> >>> [  520.261605] audit: type=1400 audit(1637212415.464:3): lsm=SMACK fn=smack_ptrace_traceme action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= pid=12685 comm="tst_pt_me" opid=12563 ocomm="bash"
> >>> [ 1445.259319] audit: type=1400 audit(1637213340.460:5): lsm=SMACK fn=smack_bprm_set_creds action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= pid=1778 comm="tst_bprm" opid=1776 ocomm="tst_bprm"
> >>>
> >>> New logs:-
> >>> [  378.098330] audit: type=1400 audit(1637212273.300:2): lsm=SMACK fn=smack_ptrace_access_check action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= tracer-pid=5189 tracer-comm="tst_pt" pid=5189 comm="tst_pt" tracee-pid=962 tracee-comm="test_tracee"
> >>> [  520.261605] audit: type=1400 audit(1637212415.464:3): lsm=SMACK fn=smack_ptrace_traceme action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= tracer-pid=6161 tracer-comm="bash" pid=6310 comm="tst_pt_me" tracee-pid=6310 tracee-comm="tst_pt_me"
> >>> [ 1445.259319] audit: type=1400 audit(1637213340.460:5): lsm=SMACK fn=smack_bprm_set_creds action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= tracer-pid=6435 tracer-comm="tst_bprm" pid=6436 comm="tst_bprm" tracee-pid=6436 tracee-comm="tst_bprm"
> >>>
> >>> Signed-off-by: Vishal Goel <vishal.goel at samsung.com>
> >>
> >> Does anyone from the audit side object to my taking this
> >> in the Smack tree?
>
> > The audit subsystem already has the "opid" and "ocomm" fields for
> > reporting on the object task info and this is even available in
> > dump_common_audit_data() via LSM_AUDIT_DATA_TASK; is there a reason
> > that can't be used instead?
>
> That info is not sufficient for debugging smack issues in ptrace calls.
> Tracee information is not printed in the logs. For eg. in below log-
> [  378.098330] audit: type=1400 audit(1637212273.300:2): lsm=SMACK fn=smack_ptrace_access_check action=denied subject="Tracer_lbl" object="Tracee_lbl" requested= pid=9397 comm="tst_pt" opid=9397 ocomm="tst_pt"
>
> There is no information of the tracee process.
> So to debug such ptrace issues, both tracer and tracee information is needed.
> That's why added new type to print both info specifically for ptrace scenarios.
 
[NOTE: please only send plaintext email to the lists]
 
From what I saw you are trying to record information about the tracer
and the tracee, yes?  The "pid", "comm", "opid", and "ocomm" fields
should be used instead of adding new fields.
 
-- 
paul-moore.com