Re: [PATCH ghak25 v2 0/9] Address NETFILTER_CFG issues

[Paul Moore]

On Thu, Jan 16, 2020 at 10:05 AM Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> wrote:
> On Mon, Jan 06, 2020 at 01:54:01PM -0500, Richard Guy Briggs wrote:
> > There were questions about the presence and cause of unsolicited syscall events
> > in the logs containing NETFILTER_CFG records and sometimes unaccompanied
> > NETFILTER_CFG records.
> >
> > During testing at least the following list of events trigger NETFILTER_CFG
> > records and the syscalls related (There may be more events that will trigger
> > this message type.):
> >       init_module, finit_module: modprobe
> >       setsockopt: iptables-restore, ip6tables-restore, ebtables-restore
> >       unshare: (h?)ostnamed
> >       clone: libvirtd
> >
> > The syscall events unsolicited by any audit rule were found to be caused by a
> > missing !audit_dummy_context() check before creating a NETFILTER_CFG
> > record and issuing the record immediately rather than saving the
> > information to create the record at syscall exit.
> > Check !audit_dummy_context() before creating the NETFILTER_CFG record.
> >
> > The vast majority of unaccompanied records are caused by the fedora default
> > rule: "-a never,task" and the occasional early startup one is I believe caused
> > by the iptables filter table module hard linked into the kernel rather than a
> > loadable module. The !audit_dummy_context() check above should avoid them.
> >
> > A couple of other factors should help eliminate unaccompanied records
> > which include commit cb74ed278f80 ("audit: always enable syscall
> > auditing when supported and audit is enabled") which makes sure that
> > when audit is enabled, so automatically is syscall auditing, and ghak66
> > which addressed initializing audit before PID 1.
> >
> > Ebtables module initialization to register tables doesn't generate records
> > because it was never hooked in to audit.  Recommend adding audit hooks to log
> > this.
> >
> > Table unregistration was never logged, which is now covered.
> >
> > Seemingly duplicate records are not actually exact duplicates that are caused
> > by netfilter table initialization in different network namespaces from the same
> > syscall.  Recommend adding the network namespace ID (proc inode and dev)
> > to the record to make this obvious (address later with ghak79 after nsid
> > patches).
> >
> > See: https://github.com/linux-audit/audit-kernel/issues/25
> > See: https://github.com/linux-audit/audit-kernel/issues/35
> > See: https://github.com/linux-audit/audit-kernel/issues/43
> > See: https://github.com/linux-audit/audit-kernel/issues/44
>
> What tree is this batch targeted to?

I believe Richard was targeting this for the audit tree.

-- 
paul moore
www.paul-moore.com