chore: import upstream snapshot with attribution

tensorflow/security/advisory/tfsa-2021-003.md

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+## TFSA-2021-003: Type confusion during tensor casts lead to dereferencing null pointers
+
+### CVE Number
+CVE-2021-29513
+
+### Impact
+Calling TF operations with tensors of non-numeric types when the operations expect
+numeric tensors result in null pointer dereferences.
+
+There are multiple ways to reproduce this, listing a few examples here:
+
+```python
+import tensorflow as tf
+import numpy as np
+data = tf.random.truncated_normal(shape=1,mean=np.float32(20.8739),stddev=779.973,dtype=20,seed=64)
+```
+
+```python
+import tensorflow as tf
+import numpy as np
+data =
+tf.random.stateless_truncated_normal(shape=1,seed=[63,70],mean=np.float32(20.8739),stddev=779.973,dtype=20)
+```
+
+```python
+import tensorflow as tf
+import numpy as np
+data = tf.one_hot(indices=[62,50],depth=136,on_value=np.int32(237),off_value=158,axis=856,dtype=20)
+```
+
+```python
+import tensorflow as tf
+import numpy as np
+data = tf.range(start=np.int32(214),limit=660,delta=129,dtype=20)
+```
+
+```python
+import tensorflow as tf
+import numpy as np
+data = tf.raw_ops.ResourceCountUpTo(resource=np.int32(30), limit=872, T=3)
+```
+
+```python
+import tensorflow as tf
+import numpy as np
+
+writer_array = np.array([1,2],dtype=np.int32)
+writer_tensor = tf.convert_to_tensor(writer_array,dtype=tf.resource)
+```
+
+All these examples and similar ones have the same behavior: the [conversion from
+Python array to C++
+array](https://github.com/tensorflow/tensorflow/blob/ff70c47a396ef1e3cb73c90513da4f5cb71bebba/tensorflow/python/lib/core/ndarray_tensor.cc#L113-L169)
+is vulnerable to a type confusion:
+
+```cc
+  int pyarray_type = PyArray_TYPE(array);
+  PyArray_Descr* descr = PyArray_DESCR(array);
+  switch (pyarray_type) {
+    ...
+    case NPY_VOID:
+      // Quantized types are currently represented as custom struct types.
+      // PyArray_TYPE returns NPY_VOID for structs, and we should look into
+      // descr to derive the actual type.
+      // Direct feeds of certain types of ResourceHandles are represented as a
+      // custom struct type.
+      return PyArrayDescr_to_TF_DataType(descr, out_tf_datatype);
+    ...
+  }
+```
+
+For the tensor types involved in the above example, the `pyarray_type` is
+`NPY_VOID` but the `descr` field is such that `descr->field = NULL`. Then
+[`PyArrayDescr_to_TF_DataType`](https://github.com/tensorflow/tensorflow/blob/ff70c47a396ef1e3cb73c90513da4f5cb71bebba/tensorflow/python/lib/core/ndarray_tensor.cc#L72-L77)
+will trigger a null dereference:
+
+```cc
+Status PyArrayDescr_to_TF_DataType(PyArray_Descr* descr,
+                                   TF_DataType* out_tf_datatype) {
+  PyObject* key;
+  PyObject* value;
+  Py_ssize_t pos = 0;
+  if (PyDict_Next(descr->fields, &pos, &key, &value)) {
+    ...
+  }
+}
+```
+
+This is because the Python's `PyDict_Next` implementation would dereference the
+first argument.
+
+### Patches
+We have patched the issue in GitHub commit
+[030af767d357d1b4088c4a25c72cb3906abac489](https://github.com/tensorflow/tensorflow/commit/030af767d357d1b4088c4a25c72cb3906abac489).
+
+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 as well as Ye Zhang and Yakun Zhang of Baidu X-Team.