int tee_session_calc_client_uuid()

in tee_core.c [198:267]

• 48 lines of code
• 10 McCabe index (conditional complexity)

int tee_session_calc_client_uuid(uuid_t *uuid, u32 connection_method,
				 const u8 connection_data[TEE_IOCTL_UUID_LEN])
{
	gid_t ns_grp = (gid_t)-1;
	kgid_t grp = INVALID_GID;
	char *name = NULL;
	int name_len;
	int rc;

	if (connection_method == TEE_IOCTL_LOGIN_PUBLIC ||
	    connection_method == TEE_IOCTL_LOGIN_REE_KERNEL) {
		/* Nil UUID to be passed to TEE environment */
		uuid_copy(uuid, &uuid_null);
		return 0;
	}

	/*
	 * In Linux environment client UUID is based on UUIDv5.
	 *
	 * Determine client UUID with following semantics for 'name':
	 *
	 * For TEEC_LOGIN_USER:
	 * uid=<uid>
	 *
	 * For TEEC_LOGIN_GROUP:
	 * gid=<gid>
	 *
	 */

	name = kzalloc(TEE_UUID_NS_NAME_SIZE, GFP_KERNEL);
	if (!name)
		return -ENOMEM;

	switch (connection_method) {
	case TEE_IOCTL_LOGIN_USER:
		name_len = snprintf(name, TEE_UUID_NS_NAME_SIZE, "uid=%x",
				    current_euid().val);
		if (name_len >= TEE_UUID_NS_NAME_SIZE) {
			rc = -E2BIG;
			goto out_free_name;
		}
		break;

	case TEE_IOCTL_LOGIN_GROUP:
		memcpy(&ns_grp, connection_data, sizeof(gid_t));
		grp = make_kgid(current_user_ns(), ns_grp);
		if (!gid_valid(grp) || !in_egroup_p(grp)) {
			rc = -EPERM;
			goto out_free_name;
		}

		name_len = snprintf(name, TEE_UUID_NS_NAME_SIZE, "gid=%x",
				    grp.val);
		if (name_len >= TEE_UUID_NS_NAME_SIZE) {
			rc = -E2BIG;
			goto out_free_name;
		}
		break;

	default:
		rc = -EINVAL;
		goto out_free_name;
	}

	rc = uuid_v5(uuid, &tee_client_uuid_ns, name, name_len);
out_free_name:
	kfree(name);

	return rc;
}