diff --git a/README.md b/README.md index 7bb18f7..8d1119a 100644 --- a/README.md +++ b/README.md @@ -52,9 +52,10 @@ configuration file and significant hardening is applied to a myriad of component - Force immediate system reboot on the occurrence of a single kernel panic, reducing the risk and impact of denial of service attacks and both cold and warm boot attacks. -- Force immediate kernel panic on OOM. This is to avoid security features such as the screen - locker, kloak, emerg-shutdown from being arbitrarily terminated when the system starts - running out of memory. +- Force immediate kernel panic on OOM (out of memory) which the above setting will force + an immediate system reboot, as opposed to placing any reliance on the oom_killer to + avoid arbitrarily terminating security features based on their OOM score. Note this creates + the risk of userspace-based denial of service attacks that maliciously fill memory. - Disable the use of legacy TIOCSTI operations which can be used to inject keypresses. diff --git a/usr/lib/sysctl.d/990-security-misc.conf#security-misc-shared b/usr/lib/sysctl.d/990-security-misc.conf#security-misc-shared index d99a580..5faeec0 100644 --- a/usr/lib/sysctl.d/990-security-misc.conf#security-misc-shared +++ b/usr/lib/sysctl.d/990-security-misc.conf#security-misc-shared @@ -199,11 +199,18 @@ kernel.perf_event_paranoid=3 ## #kernel.panic=-1 -## Force immediate kernel panic on OOM. -## This is to avoid security features such as the screen locker, kloak, emerg-shutdown -## from being arbitrarily terminated when the system starts running out of memory. +## Force immediate kernel panic on OOM (out of memory) scenarios. +## Registers a kernel panic whenever the oom_killer is triggered to kill some rouge process based on their OOM score. +## Note that this must be used with kernel.panic=-1 for it to be function as intended. +## This prevents security features such as the screen locker, kloak, and emerg-shutdown from being arbitrarily terminated. +## Enabling these two together creates a risk of userspace-based denial-of-service attacks that maliciously fill memory. +## This opinionated default forces immediate system reboot rather than placing any reliance on the oom_killer. +## +## https://en.wikipedia.org/wiki/Out_of_memory ## https://forums.whonix.org/t/screen-locker-in-security-can-we-disable-these-at-least-4-backdoors/8128/14 +## https://github.com/KSPP/kspp.github.io/issues/9 ## https://github.com/Kicksecure/security-misc/issues/324 +## vm.panic_on_oom=2 ## Disable the use of legacy TIOCSTI operations which can be used to inject keypresses.