CVE-2019-16234
Description
A flaw was found in the Linux kernel. A check was not done on the alloc_workqueue return value of the iwl_trans_pcie_alloc function potentially leading to a NULL pointer dereference. This error condition could lead to a denial of service. The highest threat from this vulnerability is to system availability.
Statement
This issue is rated as having Low impact because of the preconditions needed to trigger the error/resource cleanup code path (system-wide out-of-memory condition, high privileges or physical access). The attacker would have to be able to induce system-wide out-of-memory condition which itself could be seen as a local denial of service. It could be argued that having such privileges has the same impact as the flaw itself.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.7 | 4.7 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Red Hat CVSS v3 Score Explanation
This potential issue happens during hardware initialization, hence AV:L. The attacker needs to be able to make allocation of workqueue fail, which is possible only during system-wide low memory conditions, hence AC:H. It could be argued that having such privileges has the same impact as the flaw itself.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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