From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Guy Briggs Subject: Re: [PATCH V1] audit: add warning that an old auditd may be starved out by a new auditd Date: Thu, 17 Sep 2015 07:35:39 -0400 Message-ID: <20150917113539.GA6873@madcap2.tricolour.ca> References: <5e786f07b6d8a19927c70345c14bd1a452164d38.1441644314.git.rgb@redhat.com> <20150913160819.GT8140@madcap2.tricolour.ca> <19236209.prUueVMe32@sifl> <20150916102435.GC8140@madcap2.tricolour.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Paul Moore Cc: v.rathor@gmail.com, linux-kernel@vger.kernel.org, linux-audit@redhat.com List-Id: linux-audit@redhat.com On 15/09/16, Paul Moore wrote: > On Wed, Sep 16, 2015 at 6:24 AM, Richard Guy Briggs wrote: > > On 15/09/14, Paul Moore wrote: > >> On Sunday, September 13, 2015 12:08:19 PM Richard Guy Briggs wrote: > >> > On 15/09/11, Paul Moore wrote: > >> > > Although I suppose if nothing else we could send a record indicating > >> > > that another auditd attempted to replace it ... if we can send it > >> > > great, drop the new request and be glad we audited it, if we can't > >> > > send it, reset the auditd tracking. > >> > > >> > This is actually a good idea. > >> > >> This would go well with your last patch to try harder on netlink send > >> failures. > > > > Re-looking at the AUDIT_STATUS_PID case, I'm noticing we only > > audit_log_config_change() on success. At the moment, auditd userspace > > doesn't know about this new AUDIT_PING netlink message type I'm adding > > for testing the health of the existing audit, so it will just be dropped > > by existing auditd. I think it makes sense to add > > audit_log_config_change() on both the orphaning and starving cases > > indicating the result=0 so that there is a record. Arguably the > > orphaning case can never happen again since the starving fix will > > prevent a newer auditd from running. > > Just so I'm clear, the "starving" case is when a new auditd tries to > evict a perfectly good auditd? Not evict so much as trample. It just stomps on the existing audit_pid reference and the old one isn't aware (unless it sends a status request and checks the PID value) that it has been supplanted. > Otherwise, I think adding a result/success field to the > AUDIT_CONFIG_CHANGE record makes sense as long as it doesn't break > Steve's parsing code (I don't think it will, although it may simply > ignore it, which is okay). It is already there, but never used for anything but success. I'm proposing to add code to actually report the failures too. > paul moore - RGB -- Richard Guy Briggs 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