diskimage-builder/elements/baremetal
Ian Wienand 672705831f Add a best-effort sudo safety check
As motivation for this; we have had two breakouts of dib in recent
memory.  One was a failure to unmount through symlinks in the core
code (I335316019ef948758392b03e91f9869102a472b9) and the other was
removing host keys on the build-system
(Ib01d71ff9415a0ae04d963f6e380aab9ac2260ce).

For the most part, dib runs unprivileged.  Bits of the core code are
hopefully well tested (modulo bugs like the first one!).  We give free
reign inside the chroot (although there is still some potential there
for adverse external affects via bind mounts).  Where we could be a
bit safer (and could have prevented at least the second of these
breakouts) is with some better checking that the "sudo" calls
*outside* the chroot at least looked sane.

This adds a basic check that we're using chroot or image paths when
calling sudo in those parts of elements that run *outside* the chroot.
Various files are updated to accomodate this check; mostly by just
ignoring it for existing code (I have not audited these calls).

Nobody is pretending this type of checking makes dib magically safe,
or removes the issues with it needing to do things as root during the
build.  But this can help find egregious errors like the key removal.

Change-Id: I161a5aea1d29dcdc7236f70d372c53246ec73749
2016-05-09 15:41:38 +10:00
..
cleanup.d Add a best-effort sudo safety check 2016-05-09 15:41:38 +10:00
README.rst Turn docs warnings into errors and fix issues 2015-04-27 15:03:19 +00:00

baremetal

This is the baremetal (IE: real hardware) element.

Does the following:

  • extracts the kernel and initial ramdisk of the built image.

Optional parameters:

  • DIB_BAREMETAL_KERNEL_PATTERN and DIB_BAREMETAL_INITRD_PATTERN may be supplied to specify which kernel files are preferred; this can be of use when using custom kernels that don't fit the standard naming patterns. Both variables must be provided in order for them to have any effect.