CVE-2023-53646
Description
A bounds-checking error was found in the Linux kernel Intel i915 graphics driver's performance monitoring subsystem. A local user with access to Intel GPU performance counters can trigger address validation for observability architecture counters on Xe-HP and newer hardware, causing the driver to read beyond the end of the xehp_oa_b_counters array due to a missing sentinel entry, which results in out-of-bounds memory access and denial of service through kernel crash or undefined behavior.
Statement
The issue arises because the xehp_oa_b_counters register array lacks a terminating sentinel entry (empty record) required by the reg_in_range_table validation function. When userspace interacts with the perf subsystem to configure GPU performance monitoring on affected Intel hardware (Meteor Lake and newer platforms with Xe-HP graphics), the kernel walks the array to validate counter addresses. Without the sentinel, the validation logic reads past the array boundary, accessing arbitrary adjacent kernel memory. KASAN detected a 4-byte out-of-bounds read in xehp_is_valid_b_counter_addr. While this is a memory safety violation, exploitation beyond denial of service is unlikely because the read occurs during validation logic with no direct mechanism to return the out-of-bounds data to userspace. The impact is primarily availability through potential kernel crashes or undefined behavior.
Mitigation
To mitigate this issue, prevent the i915 module from loading. See https://access.redhat.com/solutions/41278 for instructions on blacklisting kernel modules.
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 | 5.5 | 7.1 | 7.8 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | High | High |
| Integrity Impact | None | None | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/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:H/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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