Public bug reported: Ubuntu could enable CONFIG_IO_STRICT_DEVMEM to restrict userspace access of active io-memory ranges.
This could impact kernel debugability. In that case, you may reboot with iomem=relaxed on the kernel command line to override this setting. This config option is recommended by the Kernel Self Protection Project[1] and a 2019 study performed by Capsule 8 shows that it is enabled in many other major distro kernels[2]. [1] https://kernsec.org/wiki/index.php/Kernel_Self_Protection_Project/Recommended_Settings [2] https://capsule8.com/blog/millions-of-binaries-later-a-look-into-linux-hardening-in-the-wild/ In Ubuntu impish: $ grep CONFIG_IO_STRICT_DEVMEM /boot/config-* /boot/config-5.13.0-27-generic:# CONFIG_IO_STRICT_DEVMEM is not set /boot/config-5.13.0-27-lowlatency:# CONFIG_IO_STRICT_DEVMEM is not set /boot/config-5.16.3-051603-generic:# CONFIG_IO_STRICT_DEVMEM is not set /boot/config-5.16.3-051603-lowlatency:# CONFIG_IO_STRICT_DEVMEM is not set In Debian 11: $ grep CONFIG_IO_STRICT_DEVMEM /boot/config-* /boot/config-5.10.0-10-amd64:CONFIG_IO_STRICT_DEVMEM=y /boot/config-5.10.0-11-amd64:CONFIG_IO_STRICT_DEVMEM=y In Debian sid: $ grep CONFIG_IO_STRICT_DEVMEM /boot/config-* /boot/config-5.15.0-3-amd64:CONFIG_IO_STRICT_DEVMEM=y /boot/config-5.15.0-3-rt-amd64:CONFIG_IO_STRICT_DEVMEM=y ** Affects: linux (Ubuntu) Importance: Undecided Status: Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1959384 Title: CONFIG_IO_STRICT_DEVMEM could be enabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1959384/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
