Re: [RFC PATCH ghak32 V2 12/13] audit: NETFILTER_PKT: record each container ID associated with a netNS

Paul Moore
2018-04-19T13:13:17Z

On Thu, Apr 19, 2018 at 8:45 AM, Richard Guy Briggs <rgb-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> On 2018-04-18 22:10, Paul Moore wrote:
>> On Fri, Mar 16, 2018 at 5:00 AM, Richard Guy Briggs <rgb-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
>> > Add container ID auxiliary record(s) to NETFILTER_PKT event standalone
>> > records. Iterate through all potential container IDs associated with a
>> > network namespace.
>> >
>> > Signed-off-by: Richard Guy Briggs <rgb-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>> > ---
>> > kernel/audit.c | 1 +
>> > kernel/auditsc.c | 2 ++
>> > net/netfilter/xt_AUDIT.c | 15 ++++++++++++++-
>> > 3 files changed, 17 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/kernel/audit.c b/kernel/audit.c
>> > index 08662b4..3c77e47 100644
>> > --- a/kernel/audit.c
>> > +++ b/kernel/audit.c
>> > @@ -2102,6 +2102,7 @@ int audit_log_container_info(struct audit_context *context,
>> > audit_log_end(ab);
>> > return 0;
>> > }
>> > +EXPORT_SYMBOL(audit_log_container_info);
>> >
>> > void audit_log_key(struct audit_buffer *ab, char *key)
>> > {
>> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
>> > index 208da962..af68d01 100644
>> > --- a/kernel/auditsc.c
>> > +++ b/kernel/auditsc.c
>> > @@ -975,6 +975,7 @@ struct audit_context *audit_alloc_local(void)
>> > context->in_syscall = 1;
>> > return context;
>> > }
>> > +EXPORT_SYMBOL(audit_alloc_local);
>> >
>> > inline void audit_free_context(struct audit_context *context)
>> > {
>> > @@ -989,6 +990,7 @@ inline void audit_free_context(struct audit_context *context)
>> > audit_proctitle_free(context);
>> > kfree(context);
>> > }
>> > +EXPORT_SYMBOL(audit_free_context);
>> >
>> > static int audit_log_pid_context(struct audit_context *context, pid_t pid,
>> > kuid_t auid, kuid_t uid, unsigned int sessionid,
>> > diff --git a/net/netfilter/xt_AUDIT.c b/net/netfilter/xt_AUDIT.c
>> > index c502419..edaa456 100644
>> > --- a/net/netfilter/xt_AUDIT.c
>> > +++ b/net/netfilter/xt_AUDIT.c
>> > @@ -71,10 +71,14 @@ static bool audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
>> > {
>> > struct audit_buffer *ab;
>> > int fam = -1;
>> > + struct audit_context *context = audit_alloc_local();
>> > + struct audit_containerid *cont;
>> > + int i = 0;
>> > + struct net *net;
>> >
>> > if (audit_enabled == 0)
>> > goto errout;
>>
>> Do I need to say it? I probably should ... the allocation should
>> happen after the audit_enabled check.
>
> Already fixed in V3 in my tree a couple of weeks ago...

... which you never posted, at least not anywhere I've seen. Which
effectively means I wasted a good chunk of time reviewing this code
late last night. Awesome.

> More timely review please?

More patience on your part?

>> > - ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
>> > + ab = audit_log_start(context, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
>> > if (ab == NULL)
>> > goto errout;
>> >
>> > @@ -104,7 +108,16 @@ static bool audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
>> >
>> > audit_log_end(ab);
>> >
>> > + net = sock_net(NETLINK_CB(skb).sk);
>> > + list_for_each_entry(cont, &net->audit_containerid, list) {
>> > + char buf[14];
>> > +
>> > + sprintf(buf, "net%u", i++);
>> > + audit_log_container_info(context, buf, cont->id);
>> > + }
>>
>> It seems like this could (should?) be hidden inside an audit function,
>> e.g. audit_log_net_containers() or something like that.
>
> Perhaps... It was open-coded since at this point there are no other
> users. That'll make this tidier though.

If the code was all contained within a single subsystem them I would
generally agree that open coding is preferable, but since we are
crossing a subsystem boundary I think it would be preferable to
abstract away the details into a separate function.

This will probably also be necessary once you change to using the
audit_net/net_generic mechanism.

--
paul moore