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References: <20230505184318.1355446-1-etienne.carriere@linaro.org>
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From:   Sumit Garg <sumit.garg@linaro.org>
Date:   Wed, 10 May 2023 15:54:09 +0530
Message-ID: <CAFA6WYOfFm9R2GynH0bN7hQ4t81T3hkJX5JurCUDG8oOU-RZ4w@mail.gmail.com>
Subject: Re: [PATCH] char: tpm: ftpm_tee: use kernel login identifier
To:     Etienne Carriere <etienne.carriere@linaro.org>
Cc:     linux-kernel@vger.kernel.org, Peter Huewe <peterhuewe@gmx.de>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Jason Gunthorpe <jgg@ziepe.ca>, linux-integrity@vger.kernel.org
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Hi Etienne,

On Sat, 6 May 2023 at 00:14, Etienne Carriere
<etienne.carriere@linaro.org> wrote:
>
> Changes fTPM TEE driver to open the TEE session with REE kernel login
> identifier rather than public login. This is needed in case fTPM service
> it denied to user land application and restricted to kernel operating
> system services only.

This is a valid restriction to avoid any unintended use of fTPM by
user-space. But has the corresponding patch landed in fTPM TA which
would enforce this restriction?

-Sumit

>
> Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
> ---
>  drivers/char/tpm/tpm_ftpm_tee.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c
> index 528f35b14fb6..6d32e260af43 100644
> --- a/drivers/char/tpm/tpm_ftpm_tee.c
> +++ b/drivers/char/tpm/tpm_ftpm_tee.c
> @@ -241,7 +241,7 @@ static int ftpm_tee_probe(struct device *dev)
>         /* Open a session with fTPM TA */
>         memset(&sess_arg, 0, sizeof(sess_arg));
>         export_uuid(sess_arg.uuid, &ftpm_ta_uuid);
> -       sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC;
> +       sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
>         sess_arg.num_params = 0;
>
>         rc = tee_client_open_session(pvt_data->ctx, &sess_arg, NULL);
> --
> 2.25.1
>