[dm-devel] Re: dm-ioctl on amd64 with 32bit userspace

[Alasdair G Kergon]

On Mon, Sep 17, 2007 at 06:57:26PM +0200, Guido Guenther wrote:
> -	if (new_name < (char *) (param + 1) ||
> +	if (new_name < (char *) ((void*)(param + 1) - 4) ||

Does this (untested) also work for you?

+	if (new_name < (char *) (align_ptr(param + 1) - 4) ||

I think that's slightly better as it should leave the 32-bit
case unchanged.

One day, we'll fix all this properly by making the structure size in the
interface architecture-independent as it should have been in the first
place...

[http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/dm-ioctl-fix-compat-bounds-test.patch
but wait for it to resync]

Alasdair
-- 
agk at redhat.com