linux-kernel - Re: [PATCH ghak46 V1] audit: normalize MAC

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Message-ID: <CAHC9VhQZdSeD7AfpLzk683Z9SPMezs5Xo_a+WJY-FPVqpWasQg@mail.gmail.com>
Date:   Tue, 17 Apr 2018 21:51:27 -0400
From:   Paul Moore <paul@...l-moore.com>
To:     Richard Guy Briggs <rgb@...hat.com>
Cc:     Linux-Audit Mailing List <linux-audit@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>,
        SElinux list <selinux@...ho.nsa.gov>,
        Linux Security Module list 
        <linux-security-module@...r.kernel.org>,
        Eric Paris <eparis@...hat.com>, Steve Grubb <sgrubb@...hat.com>
Subject: Re: [PATCH ghak46 V1] audit: normalize MAC_STATUS record

On Tue, Apr 17, 2018 at 6:09 PM, Richard Guy Briggs <rgb@...hat.com> wrote:
> On 2018-04-17 17:59, Paul Moore wrote:
>> On Wed, Apr 11, 2018 at 5:08 PM, Paul Moore <paul@...l-moore.com> wrote:
>> > On Mon, Apr 9, 2018 at 7:34 PM, Richard Guy Briggs <rgb@...hat.com> wrote:
>> >> There were two formats of the audit MAC_STATUS record, one of which was more
>> >> standard than the other.  One listed enforcing status changes and the
>> >> other listed enabled status changes with a non-standard label.  In
>> >> addition, the record was missing information about which LSM was
>> >> responsible and the operation's completion status.  While this record is
>> >> only issued on success, the parser expects the res= field to be present.
>> >>
>> >> old enforcing/permissive:
>> >> type=MAC_STATUS msg=audit(1523312831.378:24514): enforcing=0 old_enforcing=1 auid=0 ses=1
>> >> old enable/disable:
>> >> type=MAC_STATUS msg=audit(1523312831.378:24514): selinux=0 auid=0 ses=1
>> >>
>> >> List both sets of status and old values and add the lsm= field and the
>> >> res= field.
>> >>
>> >> Here is the new format:
>> >> type=MAC_STATUS msg=audit(1523293828.657:891): enforcing=0 old_enforcing=1 auid=0 ses=1 enabled=1 old-enabled=1 lsm=selinux res=1
>> >>
>> >> This record already accompanied a SYSCALL record.
>> >>
>> >> See: https://github.com/linux-audit/audit-kernel/issues/46
>> >> Signed-off-by: Richard Guy Briggs <rgb@...hat.com>
>> >> ---
>> >>  security/selinux/selinuxfs.c | 11 +++++++----
>> >>  1 file changed, 7 insertions(+), 4 deletions(-)
>> >>
>> >> diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
>> >> index 00eed84..00b21b2 100644
>> >> --- a/security/selinux/selinuxfs.c
>> >> +++ b/security/selinux/selinuxfs.c
>> >> @@ -145,10 +145,11 @@ static ssize_t sel_write_enforce(struct file *file, const char __user *buf,
>> >>                 if (length)
>> >>                         goto out;
>> >>                 audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
>> >> -                       "enforcing=%d old_enforcing=%d auid=%u ses=%u",
>> >> +                       "enforcing=%d old_enforcing=%d auid=%u ses=%u"
>> >> +                       " enabled=%d old-enabled=%d lsm=selinux res=1",
>> >>                         new_value, selinux_enforcing,
>> >>                         from_kuid(&init_user_ns, audit_get_loginuid(current)),
>> >> -                       audit_get_sessionid(current));
>> >> +                       audit_get_sessionid(current), selinux_enabled, selinux_enabled);
>> >
>> > This looks fine.
>> >
>> >>                 selinux_enforcing = new_value;
>> >>                 if (selinux_enforcing)
>> >>                         avc_ss_reset(0);
>> >> @@ -272,9 +273,11 @@ static ssize_t sel_write_disable(struct file *file, const char __user *buf,
>> >>                 if (length)
>> >>                         goto out;
>> >>                 audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
>> >> -                       "selinux=0 auid=%u ses=%u",
>> >> +                       "enforcing=%d old_enforcing=%d auid=%u ses=%u"
>> >> +                       " enabled=%d old-enabled=%d lsm=selinux res=1",
>> >> +                       selinux_enforcing, selinux_enforcing,
>> >>                         from_kuid(&init_user_ns, audit_get_loginuid(current)),
>> >> -                       audit_get_sessionid(current));
>> >> +                       audit_get_sessionid(current), 0, 1);
>> >
>> > It needs to be said again that I'm opposed to changes like this:
>> > inserting new fields, removing fields, or otherwise changing the
>> > format in ways that aren't strictly the addition of new fields to the
>> > end of a record is a Bad Thing.  However, there are exceptions (there
>> > are *always* exceptions), and this seems like a reasonable change that
>> > shouldn't negatively affect anyone.
>> >
>> > I'll merge this once the merge window comes to a close (we are going
>> > to need to base selinux/next on v4.17-rc1).
>>
>> Merged into selinux/next, although I should mention that there were
>> some actual code changes because of the SELinux state consolidation
>> patches that went into v4.17.  The changes were small but please take
>> a look and make sure everything still looks okay to you.
>
> Ok, that was a bit disruptive, but looks ok to me.

Yes, it was a pretty big change, but it sets the stage for a few
things we are trying to do with SELinux.

Regardless, thanks for giving the merge a quick look.

-- 
paul moore
www.paul-moore.com