In a case where the host /proc mount has already been overmounted, the
MS_MOVE handling would get ENOENT when trying to hide (for instance)
"/proc/bus" because it had already hidden away "/proc". This revealed
two issues in the previous implementation of this hardening feaure:
1. No checks were done to make sure the mount was a "full" mount (it is
a mount of the root of the filesystem), but the kernel doesn't permit
a non-full mount to be converted to a full mount (for reference, see
mnt_already_visible). This just removes extra busy-work during setup.
2. ENOENT was treated as a critical error, even though it actually
indicates the mount doesn't exist and thus isn't a problem. A more
theoretically pure solution would be to store the set of mountpoints
to be hidden and only ignore the error if an ancestor directory of
the current mountpoint was already hidden, but that would just add
complexity with little justification.
In addition, better document the reasoning behind this logic so that
folks aren't confused when looking at it.
Fixes: 28a697cce3 ("rootfs: umount all procfs and sysfs with --no-pivot")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
If the values of CMT and MBM counters are zero, they will be omitted as
empty items when getting Intel RDT stats.
Remove 'omitempty' property from CMT and MBM counters to display zero
values.
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
If the cgroup's init process doesn't complete successfully, Wait returns a
non-nil error. We should still kill all the process in the cgroup if process
namespace is shared. Otherwise, it may result in process leak.
Fixes#2632
Signed-off-by: Chaitanya Bandi <kbandi@cs.stonybrook.edu>
While at it,
- change some functions to not be methods of CpusetCgroup as
they don't use any members;
- simplify isEmpty.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
fscommon.WriteFile is added specifically to work with cgroup files,
and the error it returns does not need to be wrapped.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This removes package dependency on cgroup, as following commits
make cgroup use fscommon, which would result in dependency cycle.
The code to find out memory cgroup root is not really needed,
as 99% of test envrionments will have it at /sys/fs/cgroup/memory.
If not, that means we're either on cgroupv2 or on some very custom
system, so just skip the test.
The code that checks if we're on cgroupv2 is replaced by the check
of the particular v1 control file.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
GetProcessStartTime was deprecated over three Years ago in
439eaa3584, so we may as well remove
it now.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
errors.Wrap(err, "some error") returns nil if err is nil, so it's
slightly clearer to just return early than to set the error to nil
and call errors.Wrap(). This is also somewhat defensive in case
we decide to replace `errors.Wrap()` for golang's native `%w`
wrapping.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Mrunal Patel