BIT-tensorflow-2021-29567

TensorFlow is an end-to-end open source platform for machine learning. Due to lack of validation in tf.raw_ops.SparseDenseCwiseMul, an attacker can trigger denial of service via CHECK-fails or accesses to outside the bounds of heap allocated data. Since the implementation(https://github.com/tensorflow/tensorflow/blob/38178a2f7a681a7835bb0912702a134bfe3b4d84/tensorflow/core/kernels/sparsedensebinaryopshared.cc#L68-L80) only validates the rank of the input arguments but no constraints between dimensions(https://www.tensorflow.org/apidocs/python/tf/rawops/SparseDenseCwiseMul), an attacker can abuse them to trigger internal CHECK assertions (and cause program termination, denial of service) or to write to memory outside of bounds of heap allocated tensor buffers. 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.