CVE-2017-13166

Description

A bug in the 32-bit compatibility layer of the ioctl handling code of the v4l2 video driver in the Linux kernel has been found. A memory protection mechanism ensuring that user-provided buffers always point to a userspace memory were disabled, allowing destination address to be in a kernel space. This flaw could be exploited by an attacker to overwrite a kernel memory from an unprivileged userspace process, leading to privilege escalation.

Mitigation

A systemtap script intercepting v4l2_compat_ioctl32() function of the [videodev] module and making it to return -ENOIOCTLCMD error value would work just fine, except breaking all 32bit video capturing software, but not 64bit ones.

Alternatively, blacklisting [videodev] module will work too, but it will break all video capturing software.

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 HatNVDcve.org
Base Score7.87.8N/A
Attack VectorLocalLocalN/A
Attack ComplexityLowLowN/A
Privileges RequiredLowLowN/A
User InteractionNoneNoneN/A
ScopeUnchangedUnchangedN/A
ConfidentialityHighHighN/A
Integrity ImpactHighHighN/A
Availability ImpactHighHighN/A

Vector

Red Hat: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Understanding the Weakness (CWE)

CWE-266

Access Control

Technical Impact: Gain Privileges or Assume Identity

A user can access restricted functionality and/or sensitive information that may include administrative functionality and user accounts.

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