Re: [PATCH V1] audit: add warning that an old auditd may be starved out by a new auditd
On Monday, September 07, 2015 12:58:18 PM Richard Guy Briggs wrote:
On 15/09/07, Richard Guy Briggs wrote:
> Nothing prevents a new auditd starting up and replacing a valid
> audit_pid when an old auditd is still running, effectively starving out
> the old auditd since audit_pid no longer points to the old valid auditd.
>
> There isn't an easy way to detect if an old auditd is still running on
> the existing audit_pid other than attempting to send a message to see if
> it fails. If no message to auditd has been attempted since auditd died
> unnaturally or got killed, audit_pid will still indicate it is alive.
>
> Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com>
Ok, self-nack on this one for a couple of problems...
netlink_getsockbyportid() is static to af_netlink.c and "pid" should be
task_tgid_vnr(current). Otherwise, any opinions on this approach?
> ---
> Note: Would it be too bold to actually block the registration of a new
> auditd if the netlink_getsockbyportid() call succeeded? Would other
> checks be appropriate?
Hmm. It seems like we should prevent the registration of a new auditd if we
already have an auditd instance connected, although as you say, that isn't the
easiest thing to do.
How painful would it be to return -EAGAIN to the new auditd while sending some
sort of keep-alive/ping/etc. message to the old daemon to check its status?
--
paul moore
security @ redhat