kernel-packages team mailing list archive

[Mark Russell <mark.russell@xxxxxxxxxxxxx>]

More discussion (thanks to Louis Bouchard for link):
http://lists.infradead.org/pipermail/kexec/2013-December/010571.html

Patch v3:
http://lists.infradead.org/pipermail/kexec/2013-December/010606.html

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https://bugs.launchpad.net/bugs/1259570

Title:
  kexec should get a disabling sysctl

Status in “linux” package in Ubuntu:
  Confirmed
Status in “linux” source package in Precise:
  Confirmed
Status in “linux” source package in Quantal:
  New
Status in “linux” source package in Raring:
  New
Status in “linux” source package in Saucy:
  New
Status in “linux” source package in Trusty:
  Confirmed

Bug description:
  To enable kexec makes sense for a generic distro kernel. But if your
  users have root in their virtual machines, and you want to make it
  hard for them to run code in ring 0, you commonly disable further
  module loading and you also want to disable kexec[1]. Kees Cook wrote
  up a patch[2] that we'd like to see applied to the Ubuntu kernel to
  avoid recompilation of the distro kernel.

  I'm marking this as a security issue on the ground that it's quite
  surprising that setting kernel.modules_disabled=1 as a hardening
  feature can be subverted by using kexec.

  [1] http://mjg59.dreamwidth.org/28746.html
  [2] https://lkml.org/lkml/2013/12/9/765

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