Does the order / position of audit rule's arguments matter?

Does the order / position of audit rule's arguments matter?

[Jan Lieskovsky]

Hello folks,

  wasn't able to find answer to the following question in the auditctl
manual page, thus checking here - does the order / position in which the
auditctl's | /etc/audit/audit.rules' audit rule arguments are listed in
the rule matter or all permutations of the arguments are allowed?

IOW suppose the following rule:
  -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

Is
  -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

the only allowed form or are all the other possible argument permutations [*] also
valid / supported (under assumption there isn't some option missing or some new option
added of course when compared to the original rule)?

Thank you && Regards, Jan.
--
Jan iankko Lieskovsky / Red Hat Security Technologies Team

[*] For example suppose five different /etc/audit/audit.rules configurations would use the
    forms as follows below - do all of them represent equivalent requirement / setting?
    (regardless how much it's likely they would be expressed in that form of)

-a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged
-F path=/bin/ping -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged -a always,exit
-F perm=x -F auid>=500 -F auid!=4294967295 -k privileged -a always, exit -F path/bin/ping
-F auid>=500 -F auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F perm=x
-F auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F perm=x -F auid>=500
..

Re: Does the order / position of audit rule's arguments matter?

[Steve Grubb]

On Monday, January 19, 2015 12:57:11 PM Jan Lieskovsky wrote:
> Hello folks,
> 
>   wasn't able to find answer to the following question in the auditctl
> manual page, thus checking here - does the order / position in which the
> auditctl's | /etc/audit/audit.rules' audit rule arguments are listed in
> the rule matter or all permutations of the arguments are allowed?

Yes, its a first match wins system. I tell people to order from specific to 
general. IOW, put a watch on /etc/shadow before a watch on /etc.

-Steve

> IOW suppose the following rule:
>   -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> auid!=4294967295 -k privileged
> 
> Is
>   -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> auid!=4294967295 -k privileged
> 
> the only allowed form or are all the other possible argument permutations
> [*] also valid / supported (under assumption there isn't some option
> missing or some new option added of course when compared to the original
> rule)?
> 
> Thank you && Regards, Jan.
> --
> Jan iankko Lieskovsky / Red Hat Security Technologies Team
> 
> [*] For example suppose five different /etc/audit/audit.rules configurations
> would use the forms as follows below - do all of them represent equivalent
> requirement / setting? (regardless how much it's likely they would be
> expressed in that form of)
> 
> -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F auid!=4294967295
> -k privileged -F path=/bin/ping -F perm=x -F auid>=500 -F auid!=4294967295
> -k privileged -a always,exit -F perm=x -F auid>=500 -F auid!=4294967295 -k
> privileged -a always, exit -F path/bin/ping -F auid>=500 -F
> auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F perm=x
> -F auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F
> perm=x -F auid>=500 ..
> 
> --
> Linux-audit mailing list
> Linux-audit@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-audit

Re: Does the order / position of audit rule's arguments matter?

[Richard Guy Briggs]

On 15/01/19, Steve Grubb wrote:
> On Monday, January 19, 2015 12:57:11 PM Jan Lieskovsky wrote:
> > Hello folks,
> > 
> >   wasn't able to find answer to the following question in the auditctl
> > manual page, thus checking here - does the order / position in which the
> > auditctl's | /etc/audit/audit.rules' audit rule arguments are listed in
> > the rule matter or all permutations of the arguments are allowed?
> 
> Yes, its a first match wins system. I tell people to order from specific to 
> general. IOW, put a watch on /etc/shadow before a watch on /etc.

I don't think that answers Jan's question.  I understood the question to
be the ordering of arguments *within* a rule.  I believe the answer is
"no".

so:
	-a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged
would be equivalent to:
	-a always,exit -F path=/bin/ping -F perm=x -F auid!=4294967295 -F auid>=500 -k privileged

> -Steve
> 
> > IOW suppose the following rule:
> >   -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> > auid!=4294967295 -k privileged
> > 
> > Is
> >   -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> > auid!=4294967295 -k privileged
> > 
> > the only allowed form or are all the other possible argument permutations
> > [*] also valid / supported (under assumption there isn't some option
> > missing or some new option added of course when compared to the original
> > rule)?
> > 
> > Thank you && Regards, Jan.
> > --
> > Jan iankko Lieskovsky / Red Hat Security Technologies Team
> > 
> > [*] For example suppose five different /etc/audit/audit.rules configurations
> > would use the forms as follows below - do all of them represent equivalent
> > requirement / setting? (regardless how much it's likely they would be
> > expressed in that form of)
> > 
> > -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F auid!=4294967295
> > -k privileged -F path=/bin/ping -F perm=x -F auid>=500 -F auid!=4294967295
> > -k privileged -a always,exit -F perm=x -F auid>=500 -F auid!=4294967295 -k
> > privileged -a always, exit -F path/bin/ping -F auid>=500 -F
> > auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F perm=x
> > -F auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F
> > perm=x -F auid>=500 ..

- RGB

--
Richard Guy Briggs <rbriggs@redhat.com>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545

Re: Does the order / position of audit rule's arguments matter?

[Steve Grubb]

On Monday, January 19, 2015 01:06:42 PM Richard Guy Briggs wrote:
> On 15/01/19, Steve Grubb wrote:
> > On Monday, January 19, 2015 12:57:11 PM Jan Lieskovsky wrote:
> > > Hello folks,
> > > 
> > >   wasn't able to find answer to the following question in the auditctl
> > > 
> > > manual page, thus checking here - does the order / position in which the
> > > auditctl's | /etc/audit/audit.rules' audit rule arguments are listed in
> > > the rule matter or all permutations of the arguments are allowed?
> > 
> > Yes, its a first match wins system. I tell people to order from specific
> > to
> > general. IOW, put a watch on /etc/shadow before a watch on /etc.
> 
> I don't think that answers Jan's question.  I understood the question to
> be the ordering of arguments *within* a rule.  I believe the answer is
> "no".
> 
> so:
> 	-a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F 
auid!=4294967295
> -k privileged would be equivalent to:
> 	-a always,exit -F path=/bin/ping -F perm=x -F auid!=4294967295 -F 
auid>=500
> -k privileged

If that is the case, then you want to have the fields in the order in which the 
system can decide "no" as fast as possible.

-Steve


> > -Steve
> > 
> > > IOW suppose the following rule:
> > >   -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> > > 
> > > auid!=4294967295 -k privileged
> > > 
> > > Is
> > > 
> > >   -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> > > 
> > > auid!=4294967295 -k privileged
> > > 
> > > the only allowed form or are all the other possible argument
> > > permutations
> > > [*] also valid / supported (under assumption there isn't some option
> > > missing or some new option added of course when compared to the original
> > > rule)?
> > > 
> > > Thank you && Regards, Jan.
> > > --
> > > Jan iankko Lieskovsky / Red Hat Security Technologies Team
> > > 
> > > [*] For example suppose five different /etc/audit/audit.rules
> > > configurations would use the forms as follows below - do all of them
> > > represent equivalent requirement / setting? (regardless how much it's
> > > likely they would be expressed in that form of)
> > > 
> > > -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> > > auid!=4294967295
> > > -k privileged -F path=/bin/ping -F perm=x -F auid>=500 -F
> > > auid!=4294967295
> > > -k privileged -a always,exit -F perm=x -F auid>=500 -F auid!=4294967295
> > > -k
> > > privileged -a always, exit -F path/bin/ping -F auid>=500 -F
> > > auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F
> > > perm=x
> > > -F auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F
> > > perm=x -F auid>=500 ..
> 
> - RGB
> 
> --
> Richard Guy Briggs <rbriggs@redhat.com>
> Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems,
> Red Hat Remote, Ottawa, Canada
> Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545

Re: Does the order / position of audit rule's arguments matter?

[Jan Lieskovsky]

Thank you both for quick replies.

----- Original Message -----
> From: "Steve Grubb" <sgrubb@redhat.com>
> To: "Richard Guy Briggs" <rgb@redhat.com>
> Cc: linux-audit@redhat.com, "Jan Lieskovsky" <jlieskov@redhat.com>, "Shawn Wells" <shawn@redhat.com>
> Sent: Monday, January 19, 2015 7:11:10 PM
> Subject: Re: Does the order / position of audit rule's arguments matter?
> 
> On Monday, January 19, 2015 01:06:42 PM Richard Guy Briggs wrote:
> > On 15/01/19, Steve Grubb wrote:
> > > On Monday, January 19, 2015 12:57:11 PM Jan Lieskovsky wrote:
> > > > Hello folks,
> > > > 
> > > >   wasn't able to find answer to the following question in the auditctl
> > > > 
> > > > manual page, thus checking here - does the order / position in which
> > > > the
> > > > auditctl's | /etc/audit/audit.rules' audit rule arguments are listed in
> > > > the rule matter or all permutations of the arguments are allowed?
> > > 
> > > Yes, its a first match wins system. I tell people to order from specific
> > > to
> > > general. IOW, put a watch on /etc/shadow before a watch on /etc.
> > 
> > I don't think that answers Jan's question.  I understood the question to
> > be the ordering of arguments *within* a rule.

Yes, was about this case. But good to know also order of rules matters
(to list them that way).

>  I believe the answer is
> > "no".
> > 
> > so:
> > 	-a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> auid!=4294967295
> > -k privileged would be equivalent to:
> > 	-a always,exit -F path=/bin/ping -F perm=x -F auid!=4294967295 -F
> auid>=500
> > -k privileged
> 
> If that is the case, then you want to have the fields in the order in which
> the
> system can decide "no" as fast as possible.

Meaning the audit rule's arguments to be sorted? Or just follow the form
as it's listed for example in /usr/share/doc/audit-2.3.7/stig.rules file?
(IOW action first, then path to binary, then other -F arguments - for these
to be listed in ascending alphabetical order?)

Thank you && Regards, Jan.
--
Jan iankko Lieskovsky / Red Hat Security Technologies Team

> 
> -Steve
> 
> 
> > > -Steve
> > > 
> > > > IOW suppose the following rule:
> > > >   -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> > > > 
> > > > auid!=4294967295 -k privileged
> > > > 
> > > > Is
> > > > 
> > > >   -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> > > > 
> > > > auid!=4294967295 -k privileged
> > > > 
> > > > the only allowed form or are all the other possible argument
> > > > permutations
> > > > [*] also valid / supported (under assumption there isn't some option
> > > > missing or some new option added of course when compared to the
> > > > original
> > > > rule)?
> > > > 
> > > > Thank you && Regards, Jan.
> > > > --
> > > > Jan iankko Lieskovsky / Red Hat Security Technologies Team
> > > > 
> > > > [*] For example suppose five different /etc/audit/audit.rules
> > > > configurations would use the forms as follows below - do all of them
> > > > represent equivalent requirement / setting? (regardless how much it's
> > > > likely they would be expressed in that form of)
> > > > 
> > > > -a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> > > > auid!=4294967295
> > > > -k privileged -F path=/bin/ping -F perm=x -F auid>=500 -F
> > > > auid!=4294967295
> > > > -k privileged -a always,exit -F perm=x -F auid>=500 -F auid!=4294967295
> > > > -k
> > > > privileged -a always, exit -F path/bin/ping -F auid>=500 -F
> > > > auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F
> > > > perm=x
> > > > -F auid!=4294967295 -k privileged -a always,exit -F path=/bin/ping -F
> > > > perm=x -F auid>=500 ..
> > 
> > - RGB
> > 
> > --
> > Richard Guy Briggs <rbriggs@redhat.com>
> > Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems,
> > Red Hat Remote, Ottawa, Canada
> > Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
> 
> 

Re: Does the order / position of audit rule's arguments matter?

[Steve Grubb]

On Monday, January 19, 2015 01:19:16 PM Jan Lieskovsky wrote:
> Thank you both for quick replies.
> 
> ----- Original Message -----
> 
> > From: "Steve Grubb" <sgrubb@redhat.com>
> > To: "Richard Guy Briggs" <rgb@redhat.com>
> > Cc: linux-audit@redhat.com, "Jan Lieskovsky" <jlieskov@redhat.com>, "Shawn
> > Wells" <shawn@redhat.com> Sent: Monday, January 19, 2015 7:11:10 PM
> > Subject: Re: Does the order / position of audit rule's arguments matter?
> > 
> > On Monday, January 19, 2015 01:06:42 PM Richard Guy Briggs wrote:
> > > On 15/01/19, Steve Grubb wrote:
> > > > On Monday, January 19, 2015 12:57:11 PM Jan Lieskovsky wrote:
> > > > > Hello folks,
> > > > > 
> > > > >   wasn't able to find answer to the following question in the
> > > > >   auditctl
> > > > > 
> > > > > manual page, thus checking here - does the order / position in which
> > > > > the
> > > > > auditctl's | /etc/audit/audit.rules' audit rule arguments are listed
> > > > > in
> > > > > the rule matter or all permutations of the arguments are allowed?
> > > > 
> > > > Yes, its a first match wins system. I tell people to order from
> > > > specific
> > > > to
> > > > general. IOW, put a watch on /etc/shadow before a watch on /etc.
> > > 
> > > I don't think that answers Jan's question.  I understood the question to
> > > be the ordering of arguments *within* a rule.
> 
> Yes, was about this case. But good to know also order of rules matters
> (to list them that way).
> 
> >  I believe the answer is
> >  
> > > "no".
> > > 
> > > so:
> > > 	-a always,exit -F path=/bin/ping -F perm=x -F auid>=500 -F
> > 
> > auid!=4294967295
> > 
> > > -k privileged would be equivalent to:
> > > 	-a always,exit -F path=/bin/ping -F perm=x -F auid!=4294967295 -F
> > 
> > auid>=500
> > 
> > > -k privileged
> > 
> > If that is the case, then you want to have the fields in the order in
> > which
> > the
> > system can decide "no" as fast as possible.
> 
> Meaning the audit rule's arguments to be sorted? Or just follow the form
> as it's listed for example in /usr/share/doc/audit-2.3.7/stig.rules file?
> (IOW action first, then path to binary, then other -F arguments - for these
> to be listed in ascending alphabetical order?)

Yes, the audit system is like
for each rule
  if (syscall & mask)
     for each field
        if fval != rval
           next rule
        endif
     done
     record event
  endif
done

So, by deciding "no" quickly, it can move on to the next rule to iterate over 
the fields. 

The stig.rules is ordered correctly and is intended that anyone that needs to 
STIG a box simply copies the file "as is" to the rules.d directory. Any 
problems between what the file has and what's needed should be reported here so 
the file can be corrected.

-Steve