CVE-2025-38193
개요
CVE.org에서
In the Linux kernel, the following vulnerability has been resolved: net_sched: sch_sfq: reject invalid perturb period Gerrard Tai reported that SFQ perturb_period has no range check yet, and this can be used to trigger a race condition fixed in a separate patch. We want to make sure ctl->perturb_period * HZ will not overflow and is positive. tc qd add dev lo root sfq perturb -10 # negative value : error Error: sch_sfq: invalid perturb period. tc qd add dev lo root sfq perturb 1000000000 # too big : error Error: sch_sfq: invalid perturb period. tc qd add dev lo root sfq perturb 2000000 # acceptable value tc -s -d qd sh dev lo qdisc sfq 8005: root refcnt 2 limit 127p quantum 64Kb depth 127 flows 128 divisor 1024 perturb 2000000sec Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0
내용
This patch adds validation for the perturb_period parameter in the SFQ qdisc to prevent invalid values that could result in integer overflows (e.g., negative or excessively large input). Without this fix, malformed tc input could potentially trigger kernel instability. The issue can only be triggered by privileged users with CAP_NET_ADMIN.
CVSS (Common Vulnerability Scoring System) 점수 세부 사항
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).
다음의 CVSS 지표 및 점수는 예비 정보로 검토 대상입니다.
CVSS v3 점수 분석
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| 기본 점수 | 4.4 | 5.5 | 7.8 |
| 공격 벡터 | Local | Local | Local |
| 공격 복잡성 | Low | Low | Low |
| 필요한 권한 | High | Low | Low |
| 사용자 상호 작용 | None | None | None |
| 범위 | Unchanged | Unchanged | Unchanged |
| 기밀성 | None | None | High |
| 무결성에 미치는 영향 | None | None | High |
| 가용성에 미치는 영향 | High | High | High |
벡터
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:H/I:H/A:H
취약점 이해 (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (Memory); DoS: Instability
This weakness can generally lead to undefined behavior and therefore crashes. When the calculated result is used for resource allocation, this weakness can cause too many (or too few) resources to be allocated, possibly enabling crashes if the product requests more resources than can be provided.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the overflow/wraparound results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows, which can be used to execute arbitrary code. This is usually outside the scope of the product's implicit security policy.
Availability,Other
Technical Impact: Alter Execution Logic; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
If the overflow/wraparound occurs in a loop index variable, this could cause the loop to terminate at the wrong time - too early, too late, or not at all (i.e., infinite loops). With too many iterations, some loops could consume too many resources such as memory, file handles, etc., possibly leading to a crash or other DoS.
Access Control
Technical Impact: Bypass Protection Mechanism
If integer values are used in security-critical decisions, such as calculating quotas or allocation limits, integer overflows can be used to cause an incorrect security decision.
