Re: [PATCH] Audit: fix audit nlmsg_len from the kernel

[Eric Paris <eparis@redhat.com>]

On Tue, 2009-06-02 at 16:45 -0400, Steve Grubb wrote:
> On Tuesday 02 June 2009 04:38:02 pm Eric Paris wrote:
> > > But lets fix it anyway rather than rely on dumb luck and implementation
> > > details.
> >
> > Self NAK.   Userspace was also written by someone who didn't know
> > netlink.  Since userspace is half using the netlink macros and half
> > depending on this broken nlmsg_len implementation I don't think we can
> > make any changes in the kernel and they wouldn't be backwards
> > compatible...
> 
> The netlink code is the oldest part of the audit code and predates my 
> involvement. We could fix this if userspace had a way of querying the kernel to 
> see what the audit capabilities are. There have been many times that I've 
> wanted a way to ask the kernel if certain things are supported.
> 
> -Steve

Although yes, that lets new userspace work on old and new kernels it's
not the problem I'm thinking about.  I'm more worried about new kernel
breaking old userspace, a huge no no, since the new kernel has no way of
knowing if userspace supports correct netlink semantics or not....

In any case, this patch should certainly not be applied.

-Eric