Linux Kernel up to 4.19.13 i915_gem_execbuffer.c access_ok Kernel Memory input validation

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 4.19.13. This affects the function access_ok of the file drivers/gpu/drm/i915/i915_gem_execbuffer.c. The manipulation leads to input validation (Kernel Memory). This vulnerability is referenced as CVE-2018-20669. The attack can only be performed from a local environment. No exploit is available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 4.19.13 (Operating System). It has been rated as critical. This issue affects the function access_ok of the file drivers/gpu/drm/i915/i915_gem_execbuffer.c. The manipulation with an unknown input leads to a input validation vulnerability (Kernel Memory). Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

An issue where a provided address with access_ok() is not checked was discovered in i915_gem_execbuffer2_ioctl in drivers/gpu/drm/i915/i915_gem_execbuffer.c in the Linux kernel through 4.19.13. A local attacker can craft a malicious IOCTL function call to overwrite arbitrary kernel memory, resulting in a Denial of Service or privilege escalation.

The bug was discovered 01/23/2019. The weakness was published 03/21/2019 (Website). It is possible to read the advisory at securityfocus.com. The identification of this vulnerability is CVE-2018-20669 since 01/03/2019. Attacking locally is a requirement. A simple authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/03/2023).

The vulnerability was handled as a non-public zero-day exploit for at least 57 days. During that time the estimated underground price was around $5k-$25k. The commercial vulnerability scanner Qualys is able to test this issue with plugin 172105 (OpenSUSE Security Update for the Linux Kernel (openSUSE-SU-2019:0203-1)).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at SecurityFocus (BID 106730†). Similar entries are available at VDB-130266, VDB-131935, VDB-132077 and VDB-133346. Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.19.0
• 4.19.1
• 4.19.2
• 4.19.3
• 4.19.4
• 4.19.5
• 4.19.6
• 4.19.7
• 4.19.8
• 4.19.9
• 4.19.10
• 4.19.11
• 4.19.12
• 4.19.13

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

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