CVE-2021-29515: Reference binding to null pointer in MatrixDiag* ops in TensorFlow

Background

TensorFlow is an open-source machine learning framework widely used for building and training neural networks. It provides a comprehensive set of tools and libraries for numerical computation and data flow graphs. The MatrixDiag* operations in TensorFlow are used for manipulating diagonal matrices. These operations take tensor inputs and produce diagonal matrices as outputs. However, a vulnerability has been discovered in the implementation of these operations, which allows for reference binding to a null pointer.

Vulnerability Detail

The vulnerability in the MatrixDiag* operations arises from the lack of validation for non-empty tensor arguments. The implementation does not check whether the tensor inputs are null before performing operations on them. This can lead to null pointer dereferences when the tensors are null. An attacker can exploit this vulnerability by providing null tensors as inputs to the MatrixDiag* operations, causing the program to crash or potentially execute arbitrary code. The impact of this vulnerability can range from denial of service to remote code execution.

pip install --upgrade "tensorflow==2.21.0"

Workaround

As a workaround, users can avoid passing null tensors as inputs to the MatrixDiag* operations. It is recommended to validate the tensor inputs before using them in these operations. Here is an example of how to perform the validation in Python:

import tensorflow as tf

def matrix_diag_op(diagonal, k, num_rows, num_cols, padding_value):
    if diagonal is None or k is None or num_rows is None or num_cols is None or padding_value is None:
        raise ValueError('Invalid tensor inputs')
    # Perform MatrixDiag* operations
    ...

By explicitly checking for null tensors, users can prevent the vulnerability from being exploited.

Conclusion

The vulnerability in the MatrixDiag* operations in TensorFlow allows for reference binding to a null pointer, which can lead to null pointer dereferences and potential code execution. It is crucial for users to update their TensorFlow installations to the patched versions or upgrade to TensorFlow 2.5.0 to mitigate this vulnerability. Additionally, validating tensor inputs before using them in the MatrixDiag* operations can serve as a workaround. For further support on vulnerability remediation, please contact DevNack.com.

See every vulnerability recorded for tensorflow →

FAQ