Re: [PATCH] tee: optee: Fix incorrect page free bug

[Tyler Hicks <tyhicks@linux.microsoft.com>]

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On 2021-12-15 16:29:08, Jens Wiklander wrote:
> On Wed, Dec 15, 2021 at 11:20 AM Sumit Garg <sumit.garg@linaro.org> wrote:
> >
> > Pointer to the allocated pages (struct page *page) has already
> > progressed towards the end of allocation. It is incorrect to perform
> > __free_pages(page, order) using this pointer as we would free any
> > arbitrary pages. Fix this by stop modifying the page pointer.
> >
> > Fixes: ec185dd3ab25 ("optee: Fix memory leak when failing to register shm pages")
> > Reported-by: Patrik Lantz <patrik.lantz@axis.com>
> > Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> > ---
> >  drivers/tee/optee/core.c | 6 ++----
> >  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> Looks good to me, but I think we should cc stable since that was done
> in the patch fixed by this.

Yes, please add the 'Cc: stable(a)vger.kernel.org' tag because it will
ensure that it'll be applied to the affected stable kernels or, if
there's a conflict, that we'll get an email notification to provide a
manual backport.

Tyler

> 
> Thanks,
> Jens
> 
> >
> > diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
> > index ab2edfcc6c70..2a66a5203d2f 100644
> > --- a/drivers/tee/optee/core.c
> > +++ b/drivers/tee/optee/core.c
> > @@ -48,10 +48,8 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool_mgr *poolm,
> >                         goto err;
> >                 }
> >
> > -               for (i = 0; i < nr_pages; i++) {
> > -                       pages[i] = page;
> > -                       page++;
> > -               }
> > +               for (i = 0; i < nr_pages; i++)
> > +                       pages[i] = page + i;
> >
> >                 shm->flags |= TEE_SHM_REGISTER;
> >                 rc = shm_register(shm->ctx, shm, pages, nr_pages,
> > --
> > 2.25.1
> >
>