Out of bounds read in Tensorflow

Impact

TensorFlow's [type inference](https://github.com/tensorflow/tensorflow/blob/274df9b02330b790aa8de1cee164b70f72b9b244/tensorflow/core/graph/graph.cc#L223-L229) can cause a heap OOB read as the bounds checking is done in a DCHECK (which is a no-op during production):

```cc

if (node_t.type_id() != TFT_UNSET) {

int ix = input_idx[i];

DCHECK(ix < node_t.args_size())

<< "input " << i << " should have an output " << ix

<< " but instead only has " << node_t.args_size()

<< " outputs: " << node_t.DebugString();

input_types.emplace_back(node_t.args(ix));

// ...

}

`

An attacker can control input_idx such that ix would be larger than the number of values in node_t.args.

Patches

We have patched the issue in GitHub commit [c99d98cd189839dcf51aee94e7437b54b31f8abd](https://github.com/tensorflow/tensorflow/commit/c99d98cd189839dcf51aee94e7437b54b31f8abd).

The fix will be included in TensorFlow 2.8.0. This is the only affected version.

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.