CVE-2022-49894
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: cxl/region: Fix region HPA ordering validation Some regions may not have any address space allocated. Skip them when validating HPA order otherwise a crash like the following may result: devm_cxl_add_region: cxl_acpi cxl_acpi.0: decoder3.4: created region9 BUG: kernel NULL pointer dereference, address: 0000000000000000 [..] RIP: 0010:store_targetN+0x655/0x1740 [cxl_core] [..] Call Trace: <TASK> kernfs_fop_write_iter+0x144/0x200 vfs_write+0x24a/0x4d0 ksys_write+0x69/0xf0 do_syscall_64+0x3a/0x90 store_targetN+0x655/0x1740: alloc_region_ref at drivers/cxl/core/region.c:676 (inlined by) cxl_port_attach_region at drivers/cxl/core/region.c:850 (inlined by) cxl_region_attach at drivers/cxl/core/region.c:1290 (inlined by) attach_target at drivers/cxl/core/region.c:1410 (inlined by) store_targetN at drivers/cxl/core/region.c:1453
Statement
A NULL pointer dereference was fixed in alloc_region_ref() in the cxl_region driver, which could occur when validating Host Physical Address (HPA) ordering for regions without address space allocated. The issue was triggered by attempting to access a NULL res field. Triggering this vulnerability requires privileged access to configure or modify CXL regions via sysfs interfaces, which is generally restricted to administrative users (root or equivalent).
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 | 4.4 | 5.5 | 5.5 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | High | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Red Hat CVSS v3 Score Explanation
Triggering this vulnerability requires privileged access to configure or modify CXL regions via sysfs interfaces, which is generally restricted to administrative users (root or equivalent).
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