Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix DEVMAP_HASH overflow check on 32-bit arches The devmap code allocates a number hash buckets equal to the next power of two of the max_entries value provided when creating the map. When rounding up to the next power of two, the 32-bit variable storing the number of buckets can overflow, and the code checks for overflow by checking if the truncated 32-bit value is equal to 0. However, on 32-bit arches the rounding up itself can overflow mid-way through, because it ends up doing a left-shift of 32 bits on an unsigned long value. If the size of an unsigned long is four bytes, this is undefined behaviour, so there is no guarantee that we'll end up with a nice and tidy 0-value at the end. Syzbot managed to turn this into a crash on arm32 by creating a DEVMAP_HASH with max_entries > 0x80000000 and then trying to update it. Fix this by moving the overflow check to before the rounding up operation.

Severity

 

CVSS Version 3.x CVSS Version 2.0

CVSS 3.x Severity and Metrics:

NIST: NVD

Base Score:  7.8 HIGH

Vector:  CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.

CVSS 2.0 Severity and Metrics:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to nvd@nist.gov.

Hyperlink	Resource
https://git.kernel.org/stable/c/22079b3a423382335f47d9ed32114e6c9fe88d7c	Patch
https://git.kernel.org/stable/c/225da02acdc97af01b6bc6ce1a3e5362bf01d3fb	Patch
https://git.kernel.org/stable/c/250051acc21f9d4c5c595e4fcb55986ea08c4691	Patch
https://git.kernel.org/stable/c/281d464a34f540de166cee74b723e97ac2515ec3	Patch
https://git.kernel.org/stable/c/c826502bed93970f2fd488918a7b8d5f1d30e2e3	Patch
https://git.kernel.org/stable/c/e89386f62ce9a9ab9a94835a9890883c23d9d52c	Patch
https://git.kernel.org/stable/c/edf7990baa48de5097daa9ac02e06cb4c798a737	Patch

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-119	Improper Restriction of Operations within the Bounds of a Memory Buffer	NIST

Known Affected Software Configurations Switch to CPE 2.2

CPEs loading, please wait.

Denotes Vulnerable Software
Are we missing a CPE here? Please let us know.

Change History

0 change records found show changes