Red Hat Enterprise Linux up to 8 Address Translation buffer access with incorrect length value

Summaryinfo

A vulnerability, which was classified as critical, has been found in Red Hat Enterprise Linux up to 8. Affected is an unknown function of the component Address Translation Handler. Performing a manipulation results in buffer access with incorrect length value. This vulnerability is known as CVE-2019-19339. Attacking locally is a requirement. No exploit is available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability, which was classified as critical, was found in Red Hat Enterprise Linux up to 8 (Operating System). This affects an unknown functionality of the component Address Translation Handler. The manipulation with an unknown input leads to a buffer access with incorrect length value vulnerability. CWE is classifying the issue as CWE-805. The product uses a sequential operation to read or write a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer. This is going to have an impact on availability. The summary by CVE is:

It was found that the Red Hat Enterprise Linux 8 kpatch update did not include the complete fix for CVE-2018-12207. A flaw was found in the way Intel CPUs handle inconsistency between, virtual to physical memory address translations in CPU's local cache and system software's Paging structure entries. A privileged guest user may use this flaw to induce a hardware Machine Check Error on the host processor, resulting in a severe DoS scenario by halting the processor. System software like OS OR Virtual Machine Monitor (VMM) use virtual memory system for storing program instructions and data in memory. Virtual Memory system uses Paging structures like Page Tables and Page Directories to manage system memory. The processor's Memory Management Unit (MMU) uses Paging structure entries to translate program's virtual memory addresses to physical memory addresses. The processor stores these address translations into its local cache buffer called - Translation Lookaside Buffer (TLB). TLB has two parts, one for instructions and other for data addresses. System software can modify its Paging structure entries to change address mappings OR certain attributes like page size etc. Upon such Paging structure alterations in memory, system software must invalidate the corresponding address translations in the processor's TLB cache. But before this TLB invalidation takes place, a privileged guest user may trigger an instruction fetch operation, which could use an already cached, but now invalid, virtual to physical address translation from Instruction TLB (ITLB). Thus accessing an invalid physical memory address and resulting in halting the processor due to the Machine Check Error (MCE) on Page Size Change.

The weakness was published 01/17/2020 as not defined bug report (Bugzilla). It is possible to read the advisory at bugzilla.redhat.com. This vulnerability is uniquely identified as CVE-2019-19339 since 11/27/2019. Attacking locally is a requirement. The successful exploitation needs a authentication. The technical details are unknown and an exploit is not publicly available.

Applying a patch is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Red Hat

Name

• Enterprise Linux

Version

• 8

License

• commercial

Website

• Vendor: https://www.redhat.com/

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