CVE-2019-12817

Published: 24 June 2019

arch/powerpc/mm/mmu_context_book3s64.c in the Linux kernel before 5.1.15 for powerpc has a bug where unrelated processes may be able to read/write to one another's virtual memory under certain conditions via an mmap above 512 TB. Only a subset of powerpc systems are affected.

From the Ubuntu Security Team

It was discovered that the Linux kernel did not properly separate certain memory mappings when creating new userspace processes on 64-bit Power (ppc64el) systems. A local attacker could use this to access memory contents or cause memory corruption of other processes on the system.

Notes

The vulnerability was introduced in upstream kernel version v4.17
This issue only affects ppc64el. The 32-bit powerpc architecture is
not affected.
Power8, Power7, Power6, Power5, and older 64-bit Power systems are
affected by default
Power9 LPARs running under PowerVM are affected by default. This
issue does not affect Power9 bare metal systems by default. Power9 bare metal
is only affected when "disable_radix" is specified as a kernel boot option.

Status

Severity score breakdown

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12817
• https://ubuntu.com/security/notices/USN-4031-1
• NVD
• Launchpad
• Debian