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

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Date:   Tue, 17 Apr 2018 17:59:05 -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 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.

>>         }
>>
>>         length = count;
>> --
>> 1.8.3.1

-- 
paul moore
www.paul-moore.com