Processes can watch /proc/self/mounts or /mountinfo, and the kernel
will notify them whenever the namespace's mount table is modified. The
notified process still needs to read and parse the mountinfo to
determine what changed once notified. Many such processes, including
udisksd and SystemD < v248, make no attempt to rate-limit their
mountinfo notifications. This tends to not be a problem on many systems,
where mount tables are small and mounting and unmounting is uncommon.
Every runC exec which successfully uses the try_bindfd container-escape
mitigation performs two mount()s and one umount() in the host's mount
namespace, causing any mount-watching processes to wake up and parse the
mountinfo file three times in a row. Consequently, using 'exec' health
checks on containers has a larger-than-expected impact on system load
when such mount-watching daemons are running. Furthermore, the size of
the mount table in the host's mount namespace tends to be proportional
to the number of OCI containers as a unique mount is required for the
rootfs of each container. Therefore, on systems with mount-watching
processes, the system load increases *quadratically* with the number of
running containers which use health checks!
Prevent runC from incidentally modifying the host's mount namespace for
container-escape mitigations by setting up the mitigation in a temporary
mount namespace.
Signed-off-by: Cory Snider <csnider@mirantis.com>
Modify receive_fd() and send_fd() so they can be more readily reused in
cloned_binary.c. Change receive_fd() to have a single responsibility:
receiving and returning a single file descriptor over a UNIX domain
socket. Make send_fd() useable in precarious execution contexts such as
a clone(CLONE_VFORK|CLONE_VM) "thread" where allocating heap memory or
calling exit() would be dangerous.
Signed-off-by: Cory Snider <csnider@mirantis.com>
I am nominating @lifubang for the role of runc maintainer.
He provided a number of valuable contributions to runc, and demonstrated
both deep technical expertise and the long term commitment to the
project.
As noted in MAINTAINERS_GUIDE.md, we have a week to vote, and need to
get 66% of current maintainers' votes.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
The passing run (with the fix) looks like this:
----
delete.bats
✓ runc delete removes failed systemd unit [4556]
runc spec (status=0):
runc run -d --console-socket /tmp/bats-run-B08vu1/runc.lbQwU5/tty/sock test-failed-unit (status=0):
Warning: The unit file, source configuration file or drop-ins of runc-cgroups-integration-test-12869.scope changed on disk. Run 'systemctl daemon-reload' to reload units.
× runc-cgroups-integration-test-12869.scope - libcontainer container integration-test-12869
Loaded: loaded (/run/systemd/transient/runc-cgroups-integration-test-12869.scope; transient)
Transient: yes
Drop-In: /run/systemd/transient/runc-cgroups-integration-test-12869.scope.d
└─50-DevicePolicy.conf, 50-DeviceAllow.conf
Active: failed (Result: timeout) since Tue 2023-06-13 14:41:38 PDT; 751ms ago
Duration: 2.144s
CPU: 8ms
Jun 13 14:41:34 kir-rhat systemd[1]: Started runc-cgroups-integration-test-12869.scope - libcontainer container integration-test-12869.
Jun 13 14:41:37 kir-rhat systemd[1]: runc-cgroups-integration-test-12869.scope: Scope reached runtime time limit. Stopping.
Jun 13 14:41:38 kir-rhat systemd[1]: runc-cgroups-integration-test-12869.scope: Stopping timed out. Killing.
Jun 13 14:41:38 kir-rhat systemd[1]: runc-cgroups-integration-test-12869.scope: Killing process 1107438 (sleep) with signal SIGKILL.
Jun 13 14:41:38 kir-rhat systemd[1]: runc-cgroups-integration-test-12869.scope: Failed with result 'timeout'.
runc delete test-failed-unit (status=0):
Unit runc-cgroups-integration-test-12869.scope could not be found.
----
Before the fix, the test was failing like this:
----
delete.bats
✗ runc delete removes failed systemd unit
(in test file tests/integration/delete.bats, line 194)
`run -4 systemctl status "$SD_UNIT_NAME"' failed, expected exit code 4, got 3
....
----
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
runc delete is supposed to remove all the container's artefacts.
In case systemd cgroup driver is used, and the systemd unit has failed
(e.g. oom-killed), systemd won't remove the unit (that is, unless the
"CollectMode: inactive-or-failed" property is set).
Call reset-failed from manager.Destroy so the failed unit will be
removed during "runc delete".
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Sometimes we call resetFailedUnit as a cleanup measure, and we don't
care if it fails or not. So, move error reporting to its callers, and
ignore error in cases we don't really expect it to succeed.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
There is no such thing as linux.resources.memorySwap (the mem+swap is
set as linux.resources.memory.swap).
As it is not used in this test anyway, remove it.
Fixes: 4929c05ad1
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Replace a panic with a warning, unless it's ENOENT and we're running in
a user namespace. In the latter case, do the same as before, i.e. report
the error but using a Debug logging level.
This prevents software that uses libcontainer from panicking in
some exotic setups.
This will also print a warning on some very old systems which does not
use /sys/fs/cgroup for cgroup mount point. My bet is such systems no
longer exist.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
When a directory already exists (or after a container is restarted) the
perms of the directory being mounted to were being used even when a
different permission is set on the tmpfs mount options.
This prepends the original directory perms to the mount options.
If the perms were already set in the mount opts then those perms will
win.
This eliminates the need to perform a chmod after mount entirely.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Remove some old exceptions (no longer needed), add a new one
(codespell 2.2.5 flags "(mis)features" in docs/terminal.md).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
We used to skip testing rootless integration tests for systemd, because
in case of cgroup v1 it does not support user delegation.
Since we added ubuntu 22.04 to the testing matrix, we can actually test
rootless+systemd there (with the proper systemd setup).
Fixes: 953e1cc485
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
We read output from the following files if they exists:
- cpu.pressure
- memory.pressure
- io.pressure
Each are in format:
```
some avg10=0.00 avg60=0.00 avg300=0.00 total=0
full avg10=0.00 avg60=0.00 avg300=0.00 total=0
```
Signed-off-by: Daniel Dao <dqminh89@gmail.com>
Co-authored-by: Sandor Szücs <sandor.szuecs@zalando.de>
Co-authored-by: Kir Kolyshkin <kolyshkin@gmail.com>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Apparently, developer.gnome.org/documentation no longer hosts the
documentation we used to refer to. Link to docs.gtk.org instead.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
In code we have frozen the cgroup to avoid the processes get
an occasional "permission denied" error, while the systemd's application of device
rules is done disruptively. When the processes in the container can not
be frozen over 2 seconds (which defined in fs/freezer.go),
we still update the cgroup which resulting the container get an occasional
"permission denied" error in some cases.
Return error directly without updating cgroup, when freeze fails.
Fixes: #3803
Signed-off-by: Zoe <hi@zoe.im>
Kir Kolyshkin (7):
libct: implement support for cgroup.kill
runc kill: drop -a option
libct: move killing logic to container.Signal
libct: fix shared pidns detection
libct: signalAllProcesses: remove child reaping
tests/int/kill: add kill -a with host pidns test
tests/rootless.sh: drop set -x
LGTMs: AkihiroSuda cyphar
Closes#3825
lfbzhm