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Deadlock in mutually recursive `tf.function` objects

Moderate severity GitHub Reviewed Published Nov 4, 2021 in tensorflow/tensorflow • Updated Nov 7, 2024

Package

pip tensorflow (pip)

Affected versions

>= 2.6.0, < 2.6.1
>= 2.5.0, < 2.5.2
< 2.4.4

Patched versions

2.6.1
2.5.2
2.4.4
pip tensorflow-cpu (pip)
>= 2.6.0, < 2.6.1
>= 2.5.0, < 2.5.2
< 2.4.4
2.6.1
2.5.2
2.4.4
pip tensorflow-gpu (pip)
>= 2.6.0, < 2.6.1
>= 2.5.0, < 2.5.2
< 2.4.4
2.6.1
2.5.2
2.4.4

Description

Impact

The code behind tf.function API can be made to deadlock when two tf.function decorated Python functions are mutually recursive:

import tensorflow as tf

@tf.function()               
def fun1(num):
    if num == 1:
        return
    print(num)
    fun2(num-1)

@tf.function()
def fun2(num):
    if num == 0:
        return
    print(num)
    fun1(num-1)

fun1(9)

This occurs due to using a non-reentrant Lock Python object.

Loading any model which contains mutually recursive functions is vulnerable. An attacker can cause denial of service by causing users to load such models and calling a recursive tf.function, although this is not a frequent scenario.

Patches

We have patched the issue in GitHub commit afac8158d43691661ad083f6dd9e56f327c1dcb7.

The fix will be included in TensorFlow 2.7.0. We will also cherrypick this commit on TensorFlow 2.6.1, TensorFlow 2.5.2, and TensorFlow 2.4.4, 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 members of the Aivul Team from Qihoo 360.

References

@mihaimaruseac mihaimaruseac published to tensorflow/tensorflow Nov 4, 2021
Published by the National Vulnerability Database Nov 5, 2021
Reviewed Nov 8, 2021
Published to the GitHub Advisory Database Nov 10, 2021
Last updated Nov 7, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.056%
(25th percentile)

CVE ID

CVE-2021-41213

GHSA ID

GHSA-h67m-xg8f-fxcf

Source code

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