* Greg Kroah-Hartman (gre...@linuxfoundation.org) wrote:
> On Thu, Jun 27, 2013 at 02:03:44PM -0400, Mathieu Desnoyers wrote:
> > * Greg Kroah-Hartman (gre...@linuxfoundation.org) wrote:
> > > On Thu, Jun 27, 2013 at 01:35:32PM -0400, Mathieu Desnoyers wrote:
> > > > The following code snippet:
> > > >
> > > > drivers/platform/goldfish/goldfish_pipe.c:
> > > > goldfish_pipe_read_write()
> > > >
> > > > /* Ensure that the corresponding page is properly
> > > > mapped */
> > > > /* FIXME: this isn't safe or sufficient - use
> > > > get_user_pages */
> > > > if (is_write) {
> > > > char c;
> > > > /* Ensure that the page is mapped and readable
> > > > */
> > > > if (__get_user(c, (char __user *)address)) {
> > > > if (!ret)
> > > > ret = -EFAULT;
> > > > break;
> > > > }
> > > > } else {
> > > > /* Ensure that the page is mapped and writable
> > > > */
> > > > if (__put_user(0, (char __user *)address)) {
> > > > if (!ret)
> > > > ret = -EFAULT;
> > > > break;
> > > > }
> > > > }
> > > >
> > > > Seems to lack the kind of validation required to make it fail properly
> > > > if the memory range is not fully populated.
> > >
> > > This is an emulated platform only, so it's probably not a big deal,
> > > right?
> >
> > You're probably right. As long as it is not configured and somehow still
> > accessible on a production device.
>
> There is no device that could ever be "production" for this emulated
> hardware platform, unless a desktop system wants to "emulate" the
> android userspace system somehow. Then it could be "real", but even
> then, how would a user application get access to this codepath?
I think it would depend on the user access rights given to
/dev/qemu_pipe. Assuming it would be only accessible by root, this would
minimize the risks even more.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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