Memory corruption in Tensorflow

### Impact The implementation of `dlpack.to_dlpack` can be made to use uninitialized memory resulting in further memory corruption. This is because the pybind11 glue code assumes that the argument is a tensor: https://github.com/tensorflow/tensorflow/blob/0e68f4d3295eb0281a517c3662f6698992b7b2cf/tensorflow/python/tfe_wrapper.cc#L1361 However, there is nothing stopping users from passing in a Python object instead of a tensor. ```python In [2]: tf.experimental.dlpack.to_dlpack([2]) ==1720623==WARNING: MemorySanitizer: use-of-uninitialized-value #0 0x55b0ba5c410a in tensorflow::(anonymous namespace)::GetTensorFromHandle(TFE_TensorHandle*, TF_Status*) third_party/tensorflow/c/eager/dlpack.cc:46:7 #1 0x55b0ba5c38f4 in tensorflow::TFE_HandleToDLPack(TFE_TensorHandle*, TF_Status*) third_party/tensorflow/c/eager/dlpack.cc:252:26 ... ``` The uninitialized memory address is due to a `reinterpret_cast` https://github.com/tensorflow/tensorflow/blob/0e68f4d3295eb0281a517c3662f6698992b7b2cf/tensorflow/python/eager/pywrap_tensor.cc#L848-L850 Since the `PyObject` is a Python object, not a TensorFlow Tensor, the cast to `EagerTensor` fails. ### Patches We have patched the issue in 22e07fb204386768e5bcbea563641ea11f96ceb8 and will release a patch release for all affected versions. We recommend users to upgrade to TensorFlow 2.2.1 or 2.3.1. ### 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.

CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L

Severity from

GitHub (reviewed advisory)

Weakness

CWE-908

Also known as

BIT-tensorflow-2020-15193, CVE-2020-15193, PYSEC-2020-116, PYSEC-2020-273, PYSEC-2020-308

• github.com/tensorflow/tensorflow/security/advisories/GHSA-rjjg-hgv6-h69v
• nvd.nist.gov/vuln/detail/CVE-2020-15193
• github.com/tensorflow/tensorflow/commit/22e07fb204386768e5bcbea563641ea11f96ceb8
• github.com/pypa/advisory-database/tree/main/vulns/tensorflow-cpu/PYSEC-2020-273.yaml
• github.com/pypa/advisory-database/tree/main/vulns/tensorflow-gpu/PYSEC-2020-308.yaml
• github.com/pypa/advisory-database/tree/main/vulns/tensorflow/PYSEC-2020-116.yaml
• github.com/tensorflow/tensorflow
• github.com/tensorflow/tensorflow/releases/tag/v2.3.1
• lists.opensuse.org/opensuse-security-announce/2020-10/msg00065.html