Division by zero in TFLite's implementation of `SpaceToDepth`
### Impact
The `Prepare` step of the `SpaceToDepth` TFLite operator does not check for 0 before division
https://github.com/tensorflow/tensorflow/blob/5f7975d09eac0f10ed8a17dbb6f5964977725adc/tensorflow/lite/kernels/space_to_depth.cc#L63-L67.
```cc
const int block_size = params->block_size;
const int input_height = input->dims->data[1];
const int input_width = input->dims->data[2];
int output_height = input_height / block_size;
int output_width = input_width / block_size;
```
An attacker can craft a model such that `params->block_size` would be zero.
### Patches
We have patched the issue in GitHub commit 0d45ea1ca641b21b73bcf9c00e0179cda284e7e7
https://github.com/tensorflow/tensorflow/commit/0d45ea1ca641b21b73bcf9c00e0179cda284e7e7.
The fix will be included in TensorFlow 2.5.0. We will also cherrypick this commit on TensorFlow 2.4.2, TensorFlow 2.3.3, TensorFlow 2.2.3 and TensorFlow 2.1.4, as these are also affected and still in supported range.
### 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 members of the Aivul Team from Qihoo 360.