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

On Thu, Feb 15, 2018 at 1:16 AM, Kees Cook <keescook(a)chromium.org&gt; wrote: > On Wed, Feb 14, 2018 at 6:33 PM, Richard Guy Briggs <rgb(a)redhat.com&gt; wrote: >> On 2018-02-14 09:51, Kees Cook wrote: >>> On Wed, Feb 14, 2018 at 8:18 AM, Richard Guy Briggs <rgb(a)redhat.com&gt; 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(a)redhat.com&gt; >>> > --- >>> > 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. :)