CVE-2021-20291
Description
A deadlock vulnerability was found in github.com/containers/storage. When a container image is processed, each layer is unpacked using tar. If one of those layers is not a valid tar archive this causes an error leading to an unexpected situation where the code indefinitely waits for the tar unpacked stream, which never finishes. An attacker could use this vulnerability to craft a malicious image, which when downloaded and stored by an application using containers/storage, would then cause a deadlock leading to a Denial of Service (DoS).
Statement
The vulnerability was first exposed in v1.23.8 of containers/storage (and subsequently fixed in v1.28.1) with this git commit [1].
In OpenShift Container Platform (OCP) only 4.7 contains a version of CRI-O (and openshift/ose-docker-builder) which uses a vulnerable version of containers/storage. Subsequently this has been addressed in OCP 4.7.7.
Red Hat Quay quay-builder-container is not affected because it uses a version of github.com/containers/storage earlier than v1.23.8
Red Hat Openshift Virtualization is not affected because all containers depending on github.com/containers/storage use a version earlier than v1.23.8
For Red Hat OpenStack Platform, because containers/storage is not directly used by the director-operator, no update will be provided at this time for the operator containers.
[1] - https://github.com/containers/storage/blob/e9989a949a0d2c32fa82d3ff1076e33cfec58cb9/layers.go#L1332
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | 6.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU)
Inconsistent locking discipline can lead to deadlock.
Acknowledgements
Red Hat would like to thank Aviv Sasson (Palo Alto Networks) for reporting this issue.
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