diff --git a/README.md b/README.md index 48a4db9..14bd143 100644 --- a/README.md +++ b/README.md @@ -253,6 +253,9 @@ Kernel space: - Prevent runaway privileged processes from writing to block devices that are mounted by filesystems to protect against filesystem corruption and kernel crashes. +- Restrict processes from modifying their own memory mappings unless actively done via + `ptrace()` in order to limit self-modification which can trigger exploits. + Direct memory access: - Enable strict IOMMU translation to protect against some DMA attacks via the use diff --git a/etc/default/grub.d/40_kernel_hardening.cfg#security-misc-shared b/etc/default/grub.d/40_kernel_hardening.cfg#security-misc-shared index b9139a3..b6f2a66 100644 --- a/etc/default/grub.d/40_kernel_hardening.cfg#security-misc-shared +++ b/etc/default/grub.d/40_kernel_hardening.cfg#security-misc-shared @@ -273,6 +273,19 @@ GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX erst_disable" ## GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX bdev_allow_write_mounted=0" +## Restrict processes from modifying their own memory mappings. +## Prevents the use of FULL_FORCE by a processes unless via ptrace() for debugging. +## Limit self-modification which can be used trigger race condition vulnerabilities. +## +## https://lore.kernel.org/lkml/20240712-vfs-procfs-ce7e6c7cf26b@brauner/ +## https://lwn.net/Articles/983169/ +## https://github.com/a13xp0p0v/kernel-hardening-checker/pull/201 +## https://github.com/Kicksecure/security-misc/issues/330 +## +## Using "proc_mem.force_override=never" provides superior protection by never allowing overrides. +## +GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX proc_mem.force_override=ptrace" + ## 2. Direct Memory Access: ## ## https://madaidans-insecurities.github.io/guides/linux-hardening.html#dma-attacks