Linux Kernel PowerPC mmu_context_book3s64.c Virtual Memory Access Vulnerability [CVE-2019-12817]

CVE Number – CVE-2019-12817

A vulnerability in the Linux Kernel could allow a local attacker to gain elevated privileges on a targeted system.

The vulnerability exists in the arch/powerpc/mm/mmu_context_book3s64.c source code file of the affected software when it runs on certain 64-bit PowerPC platforms with the hash page table memory management unit (MMU) handling memory set above 512TB. This vulnerability could allow unrelated processes to read and write to each other’s virtual memory. An attacker could exploit the vulnerability by accessing the system and executing an application that submits malicious input to the targeted system. A successful exploit could allow the attacker to gain elevated privileges on the system. 

Kernel.org has confirmed the vulnerability and released software updates.

Analysis

• To exploit this vulnerability, the attacker must have user-level access to the targeted system. This access requirement could reduce the likelihood of a successful exploit.

Safeguards

• Administrators are advised to apply the appropriate updates.
  
  Administrators are advised to allow only trusted users to access local systems.
  
  Administrators are advised to allow only privileged users to access administration or management systems.
  
  Administrators are advised to monitor critical systems.

Vendor Announcements

• Kernel.org has released a changelog at the following link: Kernel ChangeLog-5.1.15 – commit ca72d88378b2f2444d3ec145dd442d449d3fefbc

Fixed Software

• Kernel.org has released software updates at the following link: powerpc/mm/64s/hash: Reallocate context ids on fork