Overflow/denial of service in `tf.raw_ops.ReverseSequence`

### Impact The implementation of `tf.raw_ops.ReverseSequence` allows for stack overflow and/or `CHECK`-fail based denial of service. ```python import tensorflow as tf input = tf.zeros([1, 1, 1], dtype=tf.int32) seq_lengths = tf.constant([0], shape=[1], dtype=tf.int32) tf.raw_ops.ReverseSequence( input=input, seq_lengths=seq_lengths, seq_dim=-2, batch_dim=0) ``` The [implementation](https://github.com/tensorflow/tensorflow/blob/5b3b071975e01f0d250c928b2a8f901cd53b90a7/tensorflow/core/kernels/reverse_sequence_op.cc#L114-L118) fails to validate that `seq_dim` and `batch_dim` arguments are valid. Negative values for `seq_dim` can result in stack overflow or `CHECK`-failure, depending on the version of Eigen code used to implement the operation. Similar behavior can be exhibited by invalid values of `batch_dim`. ### Patches We have patched the issue in GitHub commit [ecf768cbe50cedc0a45ce1ee223146a3d3d26d23](https://github.com/tensorflow/tensorflow/commit/ecf768cbe50cedc0a45ce1ee223146a3d3d26d23). 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 Ying Wang and Yakun Zhang 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-119, CWE-120, CWE-787

Also known as

BIT-tensorflow-2021-29575, CVE-2021-29575, PYSEC-2021-212, PYSEC-2021-503, PYSEC-2021-701

• github.com/tensorflow/tensorflow/security/advisories/GHSA-6qgm-fv6v-rfpv
• nvd.nist.gov/vuln/detail/CVE-2021-29575
• github.com/tensorflow/tensorflow/commit/ecf768cbe50cedc0a45ce1ee223146a3d3d26d23
• github.com/pypa/advisory-database/tree/main/vulns/tensorflow-cpu/PYSEC-2021-503.yaml
• github.com/pypa/advisory-database/tree/main/vulns/tensorflow-gpu/PYSEC-2021-701.yaml
• github.com/pypa/advisory-database/tree/main/vulns/tensorflow/PYSEC-2021-212.yaml
• github.com/tensorflow/tensorflow