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 - 0xBFFFFFFF).
Signed-off-by: Sumit Garg sumit.garg@linaro.org --- drivers/tee/tee_core.c | 7 +++++++ include/uapi/linux/tee.h | 9 +++++++++ 2 files changed, 16 insertions(+)
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index 37d22e3..13a016e 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -334,6 +334,13 @@ static int tee_ioctl_open_session(struct tee_context *ctx, goto out; }
+ if (arg.clnt_login >= TEE_IOCTL_LOGIN_REE_KERNEL_MIN && + arg.clnt_login <= TEE_IOCTL_LOGIN_REE_KERNEL_MAX) { + 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..b619f37 100644 --- a/include/uapi/linux/tee.h +++ b/include/uapi/linux/tee.h @@ -173,6 +173,15 @@ 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 - 0xBFFFFFFF). This range is rather + * being reserved for REE kernel clients or TEE implementation. + */ +#define TEE_IOCTL_LOGIN_REE_KERNEL_MIN 0x80000000 +#define TEE_IOCTL_LOGIN_REE_KERNEL_MAX 0xBFFFFFFF +/* Private login method for REE kernel clients */ +#define TEE_IOCTL_LOGIN_REE_KERNEL 0x80000000
/** * struct tee_ioctl_param - parameter