In the Linux kernels through 5.2.14 on the powerpc platform, a local user can read vector registers of other users processes via an interrupt. To exploit the vulnerability, a local user starts a transaction (via the hardware transactional memory instruction tbegin) and then accesses vector registers. At some point, the vector registers will be corrupted with the values from a different local Linux process because of a misused check in arch/powerpc/kernel/process.c. However, the attacker cannot predict when it happens. The only mitigation for this issue: not using FPU completely (then can use emulation instead). References: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a8318c13e79badb92bc6640704a64cc022a6eb97
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1760064]
This was fixed for Fedora with the 5.2.15 stable kernel updates.
Mitigation: When applicable rely on FPU emulation (for example by rebuilding the critical services code) instead of the hardware FPU.
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2020:1372 https://access.redhat.com/errata/RHSA-2020:1372
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2019-15031
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2020:1493 https://access.redhat.com/errata/RHSA-2020:1493