Buffer overflow in the mp_override_legacy_irq() function in arch/x86/kernel/acpi/boot.c in the Linux kernel through 4.12.2 allows local users to gain privileges via a crafted ACPI table.
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1473210]
This was fixed for Fedora with the 4.12.4 kernel updates
This issue has been addressed in the following products:
Red Hat Enterprise Linux 7
Via RHSA-2018:0654 https://access.redhat.com/errata/RHSA-2018:0654
Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates of the Red Hat products. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
This attack requires
- An attacker to be able to write to the ACPI tables ( local, privileged operation and non generalized attacks)
- The ability for the attacker to reboot the system ( local, privileged operation )
- The ACPI table changes to persist through reboots ( not common on cloud/serverless platforms )
- This modification to the table alone is able to possibly corrupt memory, but the corruption will not be enough alone, the corrupted affected memory will be overwritten with valid acpi struct data which also has to corrupt the memory in which a way the flaw can create abuse (HARD).
- The attacker will find it significantly difficult to abuse this a flaw in early-boot as injecting code/controlled execution at this point would require privileges. If an attacker had this specific privilege, there are easier ways to gain privilege escalation.