Re: [RFC PATCH ghak21 1/4] audit: make ANOM_LINK obey audit_enabled and audit_dummy_context

[Paul Moore]

On Thu, Feb 15, 2018 at 5:51 PM, Paul Moore <paul@xxxxxxxxxxxxxx> wrote:
> On Thu, Feb 15, 2018 at 1:16 AM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>> On Wed, Feb 14, 2018 at 6:33 PM, Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
>>> On 2018-02-14 09:51, Kees Cook wrote:
>>>> On Wed, Feb 14, 2018 at 8:18 AM, Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
>>>> > Audit link denied events emit disjointed records when audit is disabled.
>>>> > No records should be emitted when audit is disabled.
>>>> >
>>>> > See: https://github.com/linux-audit/audit-kernel/issues/21
>>>> > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
>>>> > ---
>>>> >  kernel/audit.c | 3 +++
>>>> >  1 file changed, 3 insertions(+)
>>>> >
>>>> > diff --git a/kernel/audit.c b/kernel/audit.c
>>>> > index 227db99..4c3fd24 100644
>>>> > --- a/kernel/audit.c
>>>> > +++ b/kernel/audit.c
>>>> > @@ -2261,6 +2261,9 @@ void audit_log_link_denied(const char *operation, const struct path *link)
>>>> >         struct audit_buffer *ab;
>>>> >         struct audit_names *name;
>>>> >
>>>> > +       if (!audit_enabled || audit_dummy_context())
>>>> > +               return;
>>>> > +
>>>> >         name = kzalloc(sizeof(*name), GFP_NOFS);
>>>> >         if (!name)
>>>> >                 return;
>>>>
>>>> Doesn't this means errors here would be silent if audit isn't enabled?
>>>> I don't that; sysadmins should see this notification regardless of the
>>>> audit state...
>>>
>>> This is a user error and not a system error, so I would think if system
>>> auditing is disabled, they don't care about this kind of error.
>>
>> It could indicate an attack attempt...
>
> We get beat up by several folks when we emit audit records with audit
> disabled, and they have a very valid point.
>
> I'm not arguing that the information isn't useful, I'm arguing that if
> you are interested in the sort of information that audit provides you
> should enable audit.  :)

FYI, merged into audit/next.

-- 
paul moore
www.paul-moore.com