Re: kernel BUG at drivers/android/binder_alloc.c:LINE! (4)

[Todd Kjos]

On Tue, Jun 18, 2019 at 10:37 AM Todd Kjos <tkjos@xxxxxxxxxx> wrote:
>
> On Tue, Jun 18, 2019 at 5:18 AM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> >
> > It's weird that that binder_alloc_copy_from_buffer() is a void function.
> > It would be easier to do the error handling at that point, instead of in
> > the callers.  It feels like we keep hitting similar bugs to this.

I took your advice. Fix posted: https://lkml.org/lkml/2019/6/28/857

-Todd

>
> The idea is that if it is an error that the user can cause, it is
> checked by the caller of binder_alloc_copy_from_buffer(). Most uses
> are kernel cases where the expected alignments should be fine and it's
> a BUG if they are not.
>
> Admittedly, a few cases (like this one) have slipped through since
> they cannot happen in Android (syzkaller has been very useful to find
> our bad assumptions).
>
> -Todd
>
> >
> > regards,
> > dan carpenter
> >