Re: [PATCH 0/2] net_sched: Remove broken tc actions

On 10/27/13 09:40, Eric W. Biederman wrote:

While auditing the code to make certain it would be safe to enable the
user namespace root to use tc actions I stumbled on the strange fact
that two of the tc modules in the kernel have been broken for more
years than I care to think about.

In particular neither of these two modules implements the tc_action_ops
lookup method.  Which means that in practice neither RTM_GETACTION nor
RTM_DELACTION work.  And with RTM_DELACTION broken that looks like a
permanent leak of kernel memory to me.

 >

A leak I am not happy at root having and certainly not something I want
to allow unprivileged users access to.

On the premise that 5+ years is too long to wait for someone to notice,
complain and get this code fixed let's just remove these broken tc
modules.

Nah, dude.
You dont have to implement the get/del. Actions are typically bound
to filters; when the filters disappears the action is destroyed.
You Get the filter, you Get the bound actions.
you can add actions without filters - but in such a case, for both
of these ones you picked, you can dump or flush them unless they are
bound to a filter. Thats the minimal requirement (which is met).

What is your use case to need explicit get/del?
Given act_simple is pedagogical in nature, I think
that will be useful for illustration purposes.

cheers,
jamal