CVE-2023-53485
Description
A vulnerability has been identified in the Linux kernel component for the journaled file system (JFS) within the function dbAllocDmapLev(). Specifically, the leafidx variable can become negative, and then the code uses it in an array index operation dp->tree.stree[leafidx + LEAFIND] leading to damage of system availability
Statement
A moderate severity out-of-bounds array access was found in the Linux kernel's JFS file system code. In dbAllocDmapLev(), a negative leafidx value can be used to index dp->tree.stree[leafidx + LEAFIND], triggering an out-of-bounds access reported by UBSAN. The flaw is reachable through local file operations such as file creation on a JFS file system, as reported by syzkaller, and primarily compromises system availability by crashing the kernel. Because triggering the flaw requires the ability to perform file operations on a JFS file system of an affected system, Red Hat assesses the impact as Moderate, while NIST and the CVE.org record assign a higher score of 7.8 (Important). No actively supported Red Hat product is affected: the vulnerable code is not present in the Red Hat Enterprise Linux 7, 8, 9, and 10 kernel and kernel-rt streams, nor in Red Hat In-Vehicle OS. The remaining Red Hat Enterprise Linux 6 Extended Lifecycle Support stream is out of support scope, so the residual risk is limited to out-of-support systems using a JFS file system.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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 | 6.4 | 7.8 | 7.8 |
| Attack Vector | Network | Local | Local |
| Attack Complexity | High | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | High | High |
| Integrity Impact | Low | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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)
Integrity,Availability
Technical Impact: DoS: Crash, Exit, or Restart
Use of an index that is outside the bounds of an array will very likely result in the corruption of relevant memory and perhaps instructions, leading to a crash, if the values are outside of the valid memory area.
Integrity
Technical Impact: Modify Memory
If the memory corrupted is data, rather than instructions, the system will continue to function with improper values.
Confidentiality,Integrity
Technical Impact: Modify Memory; Read Memory
Use of an index that is outside the bounds of an array can also trigger out-of-bounds read or write operations, or operations on the wrong objects; i.e., "buffer overflows" are not always the result. This may result in the exposure or modification of sensitive data.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the memory accessible by the attacker can be effectively controlled, it may be possible to execute arbitrary code, as with a standard buffer overflow and possibly without the use of large inputs if a precise index can be controlled.
Integrity,Availability,Confidentiality
Technical Impact: DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands; Read Memory; Modify Memory
A single fault could allow either an overflow (CWE-788) or underflow (CWE-786) of the array index. What happens next will depend on the type of operation being performed out of bounds, but can expose sensitive information, cause a system crash, or possibly lead to arbitrary code execution.
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