Segfault if tf.histogram_fixed_width is called with NaN values in TensorFlow
Impact
The implementation of [tf.histogram_fixed_width](https://github.com/tensorflow/tensorflow/blob/f3b9bf4c3c0597563b289c0512e98d4ce81f886e/tensorflow/core/kernels/histogram_op.cc) is vulnerable to a crash when the values array contain NaN elements:
```python
import tensorflow as tf
import numpy as np
tf.histogram_fixed_width(values=np.nan, value_range=[1,2])
```
The [implementation](https://github.com/tensorflow/tensorflow/blob/f3b9bf4c3c0597563b289c0512e98d4ce81f886e/tensorflow/core/kernels/histogram_op.cc#L35-L74) assumes that all floating point operations are defined and then converts a floating point result to an integer index:
```cc
index_to_bin.device(d) =
((values.cwiseMax(value_range(0)) - values.constant(value_range(0)))
.template cast<double>() /
step)
.cwiseMin(nbins_minus_1)
.template cast<int32>();
```
If values contains NaN then the result of the division is still NaN and the cast to int32 would result in a crash.
This only occurs on the CPU implementation.
Patches
We have patched the issue in GitHub commit [e57fd691c7b0fd00ea3bfe43444f30c1969748b5](https://github.com/tensorflow/tensorflow/commit/e57fd691c7b0fd00ea3bfe43444f30c1969748b5).
The fix will be included in TensorFlow 2.9.0. We will also cherrypick this commit on TensorFlow 2.8.1, TensorFlow 2.7.2, and TensorFlow 2.6.4, 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 externally via a [GitHub issue](https://github.com/tensorflow/tensorflow/issues/45770).
