Re: [PATCH] vfs: fix IMA lockdep circular locking dependency

[Linus Torvalds]

On Wed, May 16, 2012 at 7:13 AM, Eric Paris <eparis@xxxxxxxxxxxxxx> wrote:
>
> So we would have no checks for anonymous mappings?  We actually do
> have some controls around them today
>
> http://www.akkadia.org/drepper/selinux-mem.html
>
> It's mostly around W+X memory.  (or was W now X memory)

Ahh, ok. So I guess that won't work.

That said, I think do_brk() can already today be used to avoid those
checks, since it does a mmap with VM_DATA_DEFAULT_FLAGS, which
includes exec if the current personality includes READ_IMPLIES_EXEC -
which is trivial yo do.

I wonder if the rwx checks could be split up too - the access
protection from the *file* is really a separate issue from the access
protection of the *mapping*, if you see what I mean.. Then we could do
it at do_brk() time too.

                      Linus

>
> Admittedly with the growing prevalence of JiT stuff we are using those
> protections less and less and less....
>
> Not certain how happy some will be to see them completely disappear....
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