CVE-2020-14378
Description
An integer underflow flaw was found in the move_desc function that can lead to large amounts of CPU cycles being consumed in a long-running loop. This flaw allows an attacker to cause move_desc to get stuck in a 4,294,967,295-count iteration loop. Depending on how vhost_crypto is being used, this issue could prevent other VMs or network tasks from being serviced by the busy DPDK lcore for an extended period. The highest threat from this vulnerability is to system availability.
Statement
This flaw does not affect the versions of dpdk as shipped with Red Hat Enterprise Linux 7 and 8 or the versions embedded in Red Hat Virtualization or the Fast Datapath openvswitch package, as they do not enable generic crypto device library support. This causes the vulnerable code in vhost_crypto.c to not be included.
This flaw does not affect Red Hat Ceph Storage 3 and 4 as dpdk (embedded in ceph source rpm) is not built in the packages, therefore the vulnerable code is not available in the resulting RPM and the issue cannot be exploited.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.3 | 3.3 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Low | Low | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Instability
This weakness will generally lead to undefined behavior and therefore crashes. In the case of overflows involving loop index variables, the likelihood of infinite loops is also high.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the wrap around results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program's implicit security policy.
Acknowledgements
Red Hat would like to thank Ryan Hall for reporting this issue.
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