Re: [PATCH 2/2] firmware: qcom: qcom_tzmem: Implement sanity checks

[Bartosz Golaszewski]

On Mon, 7 Oct 2024 at 03:18, Bjorn Andersson <andersson@xxxxxxxxxx> wrote:
>
> On Sat, Oct 05, 2024 at 07:31:50PM GMT, Kuldeep Singh wrote:
> > The qcom_tzmem driver currently has multiple exposed APIs that lack
> > validations on input parameters. This oversight can lead to unexpected
> > crashes due to null pointer dereference when incorrect inputs are
> > provided.
> >
> > To address this issue, add required sanity for all input parameters in
> > the exposed APIs.
> >
>
> Unless there's good reason for the opposite, I rather see that we define
> the API to only accept valid pointers. Then if a client passes a NULL we
> get a oops with a nice callstack, which is easy to debug.
>
> The alternative is that we return -EINVAL, which not unlikely is
> propagated to some application which may or may not result in a bug
> report from a user - without any tangible information about where things
> went wrong.

Agreed, I don't think this is a good pattern in a kernel API (as
opposed to user-space interfaces where we validate everything). We
expect a certain level of sanity from in-kernel users.

Bart