[PATCH v2] efi_loader: Extra checks while opening an OPTEE session

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

Apologies for the noise.
This version should be fine! You can pick it up if you like it.

Cheers
/Ilias

On Wed, 23 Dec 2020 at 13:27, Ilias Apalodimas
<ilias.apalodimas@linaro.org> wrote:
>
> Heinrich I found a slightly better way to do it and free teh session
> on errors, so we dont have to check it.
> I'll send a v3
>
> Cheers
> /Ilias
>
>
> On Wed, 23 Dec 2020 at 13:25, Ilias Apalodimas
> <ilias.apalodimas@linaro.org> wrote:
> >
> > When opening an OP-TEE session we need to check the internal return
> > value of OP-TEE call arguments as well the return code of the
> > function itself.
> > The code was also ignoring to close the OP-TEE session in case the
> > shared memory registration failed.
> >
> > Fixes: f042e47e8fb43 ("efi_loader: Implement EFI variable handling via OP-TEE")
> > Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> > ---
> > changes since v1:
> > - add a goto tag and use it on fails
> >
> >  lib/efi_loader/efi_variable_tee.c | 20 +++++++++++++++-----
> >  1 file changed, 15 insertions(+), 5 deletions(-)
> >
> > diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c
> > index be6f3dfad469..b8808fdecad3 100644
> > --- a/lib/efi_loader/efi_variable_tee.c
> > +++ b/lib/efi_loader/efi_variable_tee.c
> > @@ -36,20 +36,29 @@ static int get_connection(struct mm_connection *conn)
> >         static const struct tee_optee_ta_uuid uuid = PTA_STMM_UUID;
> >         struct udevice *tee = NULL;
> >         struct tee_open_session_arg arg;
> > -       int rc;
> > +       int rc = -ENODEV;
> >
> >         tee = tee_find_device(tee, NULL, NULL, NULL);
> >         if (!tee)
> > -               return -ENODEV;
> > +               goto out;
> >
> >         memset(&arg, 0, sizeof(arg));
> >         tee_optee_ta_uuid_to_octets(arg.uuid, &uuid);
> >         rc = tee_open_session(tee, &arg, 0, NULL);
> > -       if (!rc) {
> > -               conn->tee = tee;
> > -               conn->session = arg.session;
> > +       if (rc)
> > +               goto out;
> > +
> > +       /* Check the internal OP-TEE result */
> > +       if (arg.ret != TEE_SUCCESS) {
> > +               rc = -EIO;
> > +               goto out;
> >         }
> >
> > +       conn->tee = tee;
> > +       conn->session = arg.session;
> > +
> > +       return 0;
> > +out:
> >         return rc;
> >  }
> >
> > @@ -88,6 +97,7 @@ static efi_status_t optee_mm_communicate(void *comm_buf, ulong dsize)
> >
> >         if (tee_shm_register(conn.tee, comm_buf, buf_size, 0, &shm)) {
> >                 log_err("Unable to register shared memory\n");
> > +               tee_close_session(conn.tee, conn.session);
> >                 return EFI_UNSUPPORTED;
> >         }
> >
> > --
> > 2.30.0.rc1
> >