CVE-2023-52455
Description
A flaw was found in the Linux kernel. When the bootloader/firmware does not set up the framebuffers, the address and size are 0 in the "iommu-addresses" property. If the IOVA region is reserved with a 0 length, it corrupts the IOVA rbtree with an entry that has pfn_hi < pfn_lo. If the intent is to use the display driver in the kernel without the framebuffer, it causes the display IOMMU mappings to fail, as an entire valid IOVA space is reserved when the address and length are passed as 0. An ideal solution would be for the firmware to remove the "iommu-addresses" property and the corresponding "memory-region" if the display is not present. The kernel should be able to handle this by checking the size of the IOVA region and skipping the IOVA reservation if its size is 0. Also, add a warning if the firmware is requesting a 0-length IOVA region reservation.
Statement
This vulnerability is rated as Low severity because it depends on specific platform firmware configurations at boot time and does not permit privilege escalation or remote exploitation. The problem occurs when Open Firmware or Device Tree data defines zero-length framebuffer memory properties, which disrupts internal IOMMU range tracking for display hardware. Typical enterprise environments and systems utilizing standard UEFI boot paths or functional framebuffer initialization are not susceptible to this failure.
Mitigation
No mitigation is currently available for this vulnerability. Make sure to perform the updates as they become available.
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 | 6.7 | 7.8 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | High | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Other,Integrity,Availability
Technical Impact: Varies by Context; DoS: Resource Consumption (CPU); Modify Memory; Read Memory
When the quantity is not properly validated, then attackers can specify malicious quantities to cause excessive resource allocation, trigger unexpected failures, enable buffer overflows, etc.
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