kernel-packages team mailing list archive

[Margarita Manterola <marga@xxxxxxxxxx>]

This bug is a feature request, and therefore requires no apport traces.
Furthermore, it also includes a link to a patch.  What's being asked
here is to apply that patch, no extra information should be needed.

** Changed in: linux (Ubuntu)
       Status: Incomplete => Confirmed

** Description changed:

  To enable kexec makes sense for a generic distro kernel. But if your
- users have root 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.
+ 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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https://bugs.launchpad.net/bugs/1259570

Title:
  kexec should get a disabling sysctl

Status in “linux” package in Ubuntu:
  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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