linux-kernel - Re: [PATCH ghak25 v2 0/9] Address NETFILTER

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Message-ID: <20200116150518.gfmzixoqagmk77rw@salvia>
Date:   Thu, 16 Jan 2020 16:05:18 +0100
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     Richard Guy Briggs <rgb@...hat.com>
Cc:     Linux-Audit Mailing List <linux-audit@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>,
        netfilter-devel@...r.kernel.org, Paul Moore <paul@...l-moore.com>,
        sgrubb@...hat.com, omosnace@...hat.com, fw@...len.de,
        twoerner@...hat.com, eparis@...isplace.org, ebiederm@...ssion.com,
        tgraf@...radead.org
Subject: Re: [PATCH ghak25 v2 0/9] Address NETFILTER_CFG issues

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?

Thanks.