tee: add TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF

The TEE subsystem allows session-based access to trusted services,
requiring a session to be established to receive a service. This
is not suitable for an environment that represents services as objects.
An object supports various operations that a client can invoke,
potentially generating a result or a new object that can be invoked
independently of the original object.

Add TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INPUT/OUTPUT/INOUT to represent an
object. Objects may reside in either TEE or userspace. To invoke an
object in TEE, introduce a new ioctl. Use the existing SUPPL_RECV and
SUPPL_SEND to invoke an object in userspace.

Reviewed-by: Sumit Garg <[e-mail]>
Tested-by: Neil Armstrong <[e-mail]>
Tested-by: Harshal Dev <[e-mail]>
Signed-off-by: Amirreza Zarrabi <[e-mail]>
Signed-off-by: Jens Wiklander <[e-mail]>

drivers/tee/tee_core.c

···
 		switch (ip.attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
 		case TEE_IOCTL_PARAM_ATTR_TYPE_NONE:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_OUTPUT:
 			break;
 		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
···
 				       params[n].u.ubuf.size))
 				return -EFAULT;
 
+			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INOUT:
+			params[n].u.objref.id = ip.a;
+			params[n].u.objref.flags = ip.b;
 			break;
 		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
···
 		case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
 			if (put_user((u64)p->u.ubuf.size, &up->b))
+				return -EFAULT;
+			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INOUT:
+			if (put_user(p->u.objref.id, &up->a) ||
+			    put_user(p->u.objref.flags, &up->b))
 				return -EFAULT;
 			break;
 		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
···
 	return rc;
 }
 
+static int tee_ioctl_object_invoke(struct tee_context *ctx,
+				   struct tee_ioctl_buf_data __user *ubuf)
+{
+	int rc;
+	size_t n;
+	struct tee_ioctl_buf_data buf;
+	struct tee_ioctl_object_invoke_arg __user *uarg;
+	struct tee_ioctl_object_invoke_arg arg;
+	struct tee_ioctl_param __user *uparams = NULL;
+	struct tee_param *params = NULL;
+
+	if (!ctx->teedev->desc->ops->object_invoke_func)
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, sizeof(buf)))
+		return -EFAULT;
+
+	if (buf.buf_len > TEE_MAX_ARG_SIZE ||
+	    buf.buf_len < sizeof(struct tee_ioctl_object_invoke_arg))
+		return -EINVAL;
+
+	uarg = u64_to_user_ptr(buf.buf_ptr);
+	if (copy_from_user(&arg, uarg, sizeof(arg)))
+		return -EFAULT;
+
+	if (sizeof(arg) + TEE_IOCTL_PARAM_SIZE(arg.num_params) != buf.buf_len)
+		return -EINVAL;
+
+	if (arg.num_params) {
+		params = kcalloc(arg.num_params, sizeof(struct tee_param),
+				 GFP_KERNEL);
+		if (!params)
+			return -ENOMEM;
+		uparams = uarg->params;
+		rc = params_from_user(ctx, params, arg.num_params, uparams);
+		if (rc)
+			goto out;
+	}
+
+	rc = ctx->teedev->desc->ops->object_invoke_func(ctx, &arg, params);
+	if (rc)
+		goto out;
+
+	if (put_user(arg.ret, &uarg->ret)) {
+		rc = -EFAULT;
+		goto out;
+	}
+	rc = params_to_user(uparams, arg.num_params, params);
+out:
+	if (params) {
+		/* Decrease ref count for all valid shared memory pointers */
+		for (n = 0; n < arg.num_params; n++)
+			if (tee_param_is_memref(params + n) &&
+			    params[n].u.memref.shm)
+				tee_shm_put(params[n].u.memref.shm);
+		kfree(params);
+	}
+	return rc;
+}
+
 static int tee_ioctl_cancel(struct tee_context *ctx,
 			    struct tee_ioctl_cancel_arg __user *uarg)
 {
···
 		case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
 			ip.a = (__force unsigned long)p->u.ubuf.uaddr;
 			ip.b = p->u.ubuf.size;
+			ip.c = 0;
+			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INOUT:
+			ip.a = p->u.objref.id;
+			ip.b = p->u.objref.flags;
 			ip.c = 0;
 			break;
 		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
···
 				return -EFAULT;
 
 			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INOUT:
+			p->u.objref.id = ip.a;
+			p->u.objref.flags = ip.b;
+			break;
 		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
 			/*
···
 		return tee_ioctl_open_session(ctx, uarg);
 	case TEE_IOC_INVOKE:
 		return tee_ioctl_invoke(ctx, uarg);
+	case TEE_IOC_OBJECT_INVOKE:
+		return tee_ioctl_object_invoke(ctx, uarg);
 	case TEE_IOC_CANCEL:
 		return tee_ioctl_cancel(ctx, uarg);
 	case TEE_IOC_CLOSE_SESSION:

include/linux/tee_core.h

···
  * @close_session:	close a session
  * @system_session:	declare session as a system session
  * @invoke_func:	invoke a trusted function
+ * @object_invoke_func:	invoke a TEE object
  * @cancel_req:		request cancel of an ongoing invoke or open
  * @supp_recv:		called for supplicant to get a command
  * @supp_send:		called for supplicant to send a response
···
 	int (*invoke_func)(struct tee_context *ctx,
 			   struct tee_ioctl_invoke_arg *arg,
 			   struct tee_param *param);
+	int (*object_invoke_func)(struct tee_context *ctx,
+				  struct tee_ioctl_object_invoke_arg *arg,
+				  struct tee_param *param);
 	int (*cancel_req)(struct tee_context *ctx, u32 cancel_id, u32 session);
 	int (*supp_recv)(struct tee_context *ctx, u32 *func, u32 *num_params,
 			 struct tee_param *param);

include/linux/tee_drv.h

···
 	size_t size;
 };
 
+struct tee_param_objref {
+	u64 id;
+	u64 flags;
+};
+
 struct tee_param_value {
 	u64 a;
 	u64 b;
···
 	u64 attr;
 	union {
 		struct tee_param_memref memref;
+		struct tee_param_objref objref;
 		struct tee_param_ubuf ubuf;
 		struct tee_param_value value;
 	} u;

include/uapi/linux/tee.h

···
 #define TEE_GEN_CAP_PRIVILEGED	(1 << 1)/* Privileged device (for supplicant) */
 #define TEE_GEN_CAP_REG_MEM	(1 << 2)/* Supports registering shared memory */
 #define TEE_GEN_CAP_MEMREF_NULL	(1 << 3)/* NULL MemRef support */
+#define TEE_GEN_CAP_OBJREF	(1 << 4)/* Supports generic object reference */
 
-#define TEE_MEMREF_NULL		(__u64)(-1) /* NULL MemRef Buffer */
+#define TEE_MEMREF_NULL		((__u64)(-1)) /* NULL MemRef Buffer */
+#define TEE_OBJREF_NULL		((__u64)(-1)) /* NULL ObjRef Object */
 
 /*
  * TEE Implementation ID
···
 #define TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT	10	/* input and output */
 
 /*
+ * These defines object reference parameters.
+ */
+#define TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INPUT	11
+#define TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_OUTPUT	12
+#define TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INOUT	13
+
+/*
  * Mask for the type part of the attribute, leaves room for more types
  */
 #define TEE_IOCTL_PARAM_ATTR_TYPE_MASK		0xff
···
  * @attr: attributes
  * @a: if a memref, offset into the shared memory object,
  *     else if a ubuf, address of the user buffer,
- *     else a value parameter
- * @b: if a memref or ubuf, size of the buffer, else a value parameter
+ *     else if an objref, object identifier, else a value parameter
+ * @b: if a memref or ubuf, size of the buffer,
+ *     else if objref, flags for the object, else a value parameter
  * @c: if a memref, shared memory identifier, else a value parameter
  *
  * @attr & TEE_PARAM_ATTR_TYPE_MASK indicates if memref, ubuf, or value is
  * used in the union. TEE_PARAM_ATTR_TYPE_VALUE_* indicates value,
- * TEE_PARAM_ATTR_TYPE_MEMREF_* indicates memref, and TEE_PARAM_ATTR_TYPE_UBUF_*
- * indicates ubuf. TEE_PARAM_ATTR_TYPE_NONE indicates that none of the members
- * are used.
+ * TEE_PARAM_ATTR_TYPE_MEMREF_* indicates memref, TEE_PARAM_ATTR_TYPE_UBUF_*
+ * indicates ubuf, and TEE_PARAM_ATTR_TYPE_OBJREF_* indicates objref.
+ * TEE_PARAM_ATTR_TYPE_NONE indicates that none of the members are used.
  *
  * Shared memory is allocated with TEE_IOC_SHM_ALLOC which returns an
  * identifier representing the shared memory object. A memref can reference
···
  *	   tee_ioctl_shm_alloc_data
  * munmap(): unmaps previously shared memory
  */
+
+/**
+ * struct tee_ioctl_invoke_func_arg - Invokes an object in a Trusted Application
+ * @id:		[in] Object id
+ * @op:		[in] Object operation, specific to the object
+ * @ret:	[out] return value
+ * @num_params:	[in] number of parameters following this struct
+ */
+struct tee_ioctl_object_invoke_arg {
+	__u64 id;
+	__u32 op;
+	__u32 ret;
+	__u32 num_params;
+	/* num_params tells the actual number of element in params */
+	struct tee_ioctl_param params[];
+};
+
+#define TEE_IOC_OBJECT_INVOKE	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 10, \
+				     struct tee_ioctl_buf_data)
 
 #endif /*__TEE_H*/