CVE-2024-50017 Information

Description

In the Linux kernel the following vulnerability has been resolved:

x86/mm/ident_map: Use gbpages only where full GB page should be mapped.

When ident_pud_init() uses only GB pages to create identity maps large ranges of addresses not actually requested can be included in the resulting table; a 4K request will map a full GB. This can include a lot of extra address space past that requested including areas marked reserved by the BIOS. That allows processor speculation into reserved regions that on UV systems can cause system halts.

Only use GB pages when map creation requests include the full GB page of space. Fall back to using smaller 2M pages when only portions of a GB page are included in the request.

No attempt is made to coalesce mapping requests. If a request requires a map entry at the 2M (pmd) level subsequent mapping requests within the same 1G region will also be at the pmd level even if adjacent or overlapping such requests could have been combined to map a full GB page. Existing usage starts with larger regions and then adds smaller regions so this should not have any great consequence.

CVSS Vector

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

Reference

https://git.kernel.org/stable/c/d80a99892f7a992d103138fa4636b2c33abd6740 https://git.kernel.org/stable/c/a23823098ab2c277c14fc110b97d8d5c83597195 https://git.kernel.org/stable/c/cc31744a294584a36bf764a0ffa3255a8e69f036

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5