from Hacker News

Tales from the Kernel Parameter Side

by MiguelHzBz on 11/4/22, 7:52 AM with 7 comments

  • by teddyh on 11/5/22, 8:07 PM

    Some of the descriptions of sysctl parameters are mixed up and wrong:

      kernel.core_uses_pid  Block USB devices
  kernel.ctrl-alt-del   Disable access to dmesg for unprivileged users
  kernel.dmesg_restrict Disable kexec to prevent kernel livepatching
  kernel.kptr_restrict  Restrict access to kernel logs
    The official documentation for /proc/sys and sysctl settings is here: https://www.kernel.org/doc/html/latest/admin-guide/sysctl/in...

    The article seems to mostly exist to be a showcase for Falco, which apparently is some sort of file change security monitor.

  • by anderspitman on 11/5/22, 8:10 PM

    I've been playing with QEMU a lot lately. Early on I encountered a fairly fundamental problem: how do you pass arbitrary data to a booting Linux system? I ended up discovering fw_cfg[0], but it feels pretty janky for this purpose and didn't seem to work for larger files like executables. Anyone aware of a better way?

    [0]: https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-f...