Re: [Tee-dev] [PATCH v4 2/2] tee: add private login method for kernel clients

On Mon, Mar 23, 2020 at 1:19 PM Sumit Garg sumit.garg@linaro.org wrote:

There are use-cases where user-space shouldn't be allowed to communicate directly with a TEE device which is dedicated to provide a specific service for a kernel client. So add a private login method for kernel clients and disallow user-space to open-session using GP implementation defined login method range: (0x80000000 - 0xFFFFFFFF).

Signed-off-by: Sumit Garg sumit.garg@linaro.org

drivers/tee/tee_core.c | 6 ++++++ include/uapi/linux/tee.h | 8 ++++++++ 2 files changed, 14 insertions(+)

Looks good.

Thanks, Jens

diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index 37d22e3..533e7a8 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -334,6 +334,12 @@ static int tee_ioctl_open_session(struct tee_context *ctx, goto out; }

•   if (arg.clnt_login & TEE_IOCTL_LOGIN_MASK) {
  

•           pr_debug("login method not allowed for user-space client\n");
  

•           rc = -EPERM;
  

•           goto out;
  

•   }
  

•   rc = ctx->teedev->desc->ops->open_session(ctx, &arg, params);
    if (rc)
            goto out;
  

diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h index 6596f3a..19172a2 100644 --- a/include/uapi/linux/tee.h +++ b/include/uapi/linux/tee.h @@ -173,6 +173,14 @@ struct tee_ioctl_buf_data { #define TEE_IOCTL_LOGIN_APPLICATION 4 #define TEE_IOCTL_LOGIN_USER_APPLICATION 5 #define TEE_IOCTL_LOGIN_GROUP_APPLICATION 6 +/*

• • Disallow user-space to use GP implementation specific login
• • method range (0x80000000 - 0xFFFFFFFF). This range is rather
• • being reserved for REE kernel clients or TEE implementation.
• */

+#define TEE_IOCTL_LOGIN_MASK 0x80000000 +/* Private login method for REE kernel clients */ +#define TEE_IOCTL_LOGIN_REE_KERNEL 0x80000000

/**

• struct tee_ioctl_param - parameter

-- 2.7.4