CHECK-fail in `tf.raw_ops.RFFT`

### Impact An attacker can cause a denial of service by exploiting a `CHECK`-failure coming from the implementation of `tf.raw_ops.RFFT`: ```python import tensorflow as tf inputs = tf.constant([1], shape=[1], dtype=tf.float32) fft_length = tf.constant([0], shape=[1], dtype=tf.int32) tf.raw_ops.RFFT(input=inputs, fft_length=fft_length) ``` The above example causes Eigen code to operate on an empty matrix. This triggers on an assertion and causes program termination. ### Patches We have patched the issue in GitHub commit [31bd5026304677faa8a0b77602c6154171b9aec1](https://github.com/tensorflow/tensorflow/commit/31bd5026304677faa8a0b77602c6154171b9aec1). 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.

CVSS 3.1

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

Severity from

GitHub (reviewed advisory)

Weakness

CWE-617

Also known as

BIT-tensorflow-2021-29563, CVE-2021-29563, PYSEC-2021-200, PYSEC-2021-491, PYSEC-2021-689

• github.com/tensorflow/tensorflow/security/advisories/GHSA-ph87-fvjr-v33w
• nvd.nist.gov/vuln/detail/CVE-2021-29563
• github.com/tensorflow/tensorflow/commit/31bd5026304677faa8a0b77602c6154171b9aec1
• github.com/pypa/advisory-database/tree/main/vulns/tensorflow-cpu/PYSEC-2021-491.yaml
• github.com/pypa/advisory-database/tree/main/vulns/tensorflow-gpu/PYSEC-2021-689.yaml
• github.com/pypa/advisory-database/tree/main/vulns/tensorflow/PYSEC-2021-200.yaml
• github.com/tensorflow/tensorflow