This allows the libcontainer to automatically clean up runc:[1:CHILD]
processes created as part of nsenter.
Signed-off-by: Alex Fang <littlelightlittlefire@gmail.com>
And convert the various start-time properties from strings to uint64s.
This removes all internal consumers of the deprecated
GetProcessStartTime function.
Signed-off-by: W. Trevor King <wking@tremily.us>
Since syscall is outdated and broken for some architectures,
use x/sys/unix instead.
There are still some dependencies on the syscall package that will
remain in syscall for the forseeable future:
Errno
Signal
SysProcAttr
Additionally:
- os still uses syscall, so it needs to be kept for anything
returning *os.ProcessState, such as process.Wait.
Signed-off-by: Christy Perez <christy@linux.vnet.ibm.com>
* User Case:
User could use prestart hook to add block devices to container. so the
hook should have a way to set the permissions of the devices.
Just move cgroup config operation before prestart hook will work.
Signed-off-by: Wentao Zhang <zhangwentao234@huawei.com>
The rootless cgroup manager acts as a noop for all set and apply
operations. It is just used for rootless setups. Currently this is far
too simple (we need to add opportunistic cgroup management), but is good
enough as a first-pass at a noop cgroup manager.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
This enables the support for the rootless container mode. There are many
restrictions on what rootless containers can do, so many different runC
commands have been disabled:
* runc checkpoint
* runc events
* runc pause
* runc ps
* runc restore
* runc resume
* runc update
The following commands work:
* runc create
* runc delete
* runc exec
* runc kill
* runc list
* runc run
* runc spec
* runc state
In addition, any specification options that imply joining cgroups have
also been disabled. This is due to support for unprivileged subtree
management not being available from Linux upstream.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
Effectively, !dumpable makes implementing rootless containers quite
hard, due to a bunch of different operations on /proc/self no longer
being possible without reordering everything.
!dumpable only really makes sense when you are switching between
different security contexts, which is only the case when we are joining
namespaces. Unfortunately this means that !dumpable will still have
issues in this instance, and it should only be necessary to set
!dumpable if we are not joining USER namespaces (new kernels have
protections that make !dumpable no longer necessary). But that's a topic
for another time.
This also includes code to unset and then re-set dumpable when doing the
USER namespace mappings. This should also be safe because in principle
processes in a container can't see us until after we fork into the PID
namespace (which happens after the user mapping).
In rootless containers, it is not possible to set a non-dumpable
process's /proc/self/oom_score_adj (it's owned by root and thus not
writeable). Thus, it needs to be set inside nsexec before we set
ourselves as non-dumpable.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
If we pass a file descriptor to the host filesystem while joining a
container, there is a race condition where a process inside the
container can ptrace(2) the joining process and stop it from closing its
file descriptor to the stateDirFd. Then the process can access the
*host* filesystem from that file descriptor. This was fixed in part by
5d93fed3d2 ("Set init processes as non-dumpable"), but that fix is
more of a hail-mary than an actual fix for the underlying issue.
To fix this, don't open or pass the stateDirFd to the init process
unless we're creating a new container. A proper fix for this would be to
remove the need for even passing around directory file descriptors
(which are quite dangerous in the context of mount namespaces).
There is still an issue with containers that have CAP_SYS_PTRACE and are
using the setns(2)-style of joining a container namespace. Currently I'm
not really sure how to fix it without rampant layer violation.
Fixes: CVE-2016-9962
Fixes: 5d93fed3d2 ("Set init processes as non-dumpable")
Signed-off-by: Aleksa Sarai <asarai@suse.de>
`HookState` struct should follow definition of `State` in runtime-spec:
* modify json name of `version` to `ociVersion`.
* Remove redundant `Rootfs` field as rootfs can be retrived from
`bundlePath/config.json`.
Signed-off-by: Zhang Wei <zhangwei555@huawei.com>
This implements {createTTY, detach} and all of the combinations and
negations of the two that were previously implemented. There are some
valid questions about out-of-OCI-scope topics like !createTTY and how
things should be handled (why do we dup the current stdio to the
process, and how is that not a security issue). However, these will be
dealt with in a separate patchset.
In order to allow for late console setup, split setupRootfs into the
"preparation" section where all of the mounts are created and the
"finalize" section where we pivot_root and set things as ro. In between
the two we can set up all of the console mountpoints and symlinks we
need.
We use two-stage synchronisation to ensures that when the syscalls are
reordered in a suboptimal way, an out-of-place read() on the parentPipe
will not gobble the ancilliary information.
This patch is part of the console rewrite patchset.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
To make the code cleaner, and more clear, refactor the syncT handling
used when creating the `runc init` process. In addition, document the
state changes so that people actually understand what is going on.
Rather than only using syncT for the standard initProcess, use it for
both initProcess and setnsProcess. This removes some special cases, as
well as allowing for the use of syncT with setnsProcess.
Also remove a bunch of the boilerplate around syncT handling.
This patch is part of the console rewrite patchset.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
This allows a user to send a signal to all the processes in the
container within a single atomic action to avoid new processes being
forked off before the signal can be sent.
This is basically taking functionality that we already use being
`delete` and exposing it ok the `kill` command by adding a flag.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Error sent from child process is already genericError, if
we don't allow recrusive generic error, we won't get any
cause infomation from parent process.
Before, we got:
WARN[0000] exit status 1
ERRO[0000] operation not permitted
After, we got:
WARN[0000] exit status 1
ERRO[0000] container_linux.go:247: starting container process caused "process_linux.go:359: container init caused \"operation not permitted\""
it's not pretty but useful for detecting root causes.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
This removes the use of a signal handler and SIGCONT to signal the init
process to exec the users process.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
In user namespaces, we need to make sure we don't chown() the console to
unmapped users. This means we need to get both the UID and GID of the
root user in the container when changing the owner.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
This is the inital port of the libcontainer.Error to added a cause to
all the existing error messages. Going forward, when an error can be
wrapped because it is not being checked at the higher levels for
something like `os.IsNotExist` we can add more information to the error
message like cause and stack file/line information. This will help
higher level tools to know what cause a container start or operation to
fail.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Fixes#680
This changes setupRlimit to use the Prlimit syscall (rather than
Setrlimit) and moves the call to the parent process. This is necessary
because Setrlimit would affect the libcontainer consumer if called in
the parent, and would fail if called from the child if the
child process is in a user namespace and the requested rlimit is higher
than that in the parent.
Signed-off-by: Julian Friedman <julz.friedman@uk.ibm.com>
The re-work of namespace entering lost the setuid/setgid that was part
of the Go-routine based process exec in the prior code. A side issue was
found with setting oom_score_adj before execve() in a userns that is
also solved here.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
This simply move the call to the Prestart hooks to be made once we
receive the procReady message from the client.
This is necessary as we had to move the setns calls within nsexec in
order to be accomodate joining namespaces that only affect future
children (e.g. NEWPID).
Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
An init process can join other namespaces (pidns, ipc etc.). This leverages
C code defined in nsenter package to spawn a process with correct namespaces
and clone if necessary.
This moves all setns and cloneflags related code to nsenter layer, which mean
that we dont use Go os/exec to create process with cloneflags and set
uid/gid_map or setgroups anymore. The necessary data is passed from Go to C
using a netlink binary-encoding format.
With this change, setns and init processes are almost the same, which brings
some opportunity for refactoring.
Signed-off-by: Daniel, Dao Quang Minh <dqminh89@gmail.com>
[mickael.laventure@docker.com: adapted to apply on master @ d97d5e]
Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@docker.com>
Today mounts in pre-start hooks get overriden by the default mounts.
Moving the pre-start hooks to after the container mounts and before
the pivot/move root gives better flexiblity in the hooks.
Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
It's never used and not needed. Our pipe is created with
syscall.SOCK_CLOEXEC, so pipe will be closed once container
process executed successfully, parent process will read EOF
and continue. If container process got error before executed,
we'll write procError to sync with parent.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Marshall the raw objects for the sync pipes so that no new line chars
are left behind in the pipe causing errors.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Due to the fact that the init is implemented in Go (which seemingly
randomly spawns new processes and loves eating memory), most cgroup
configurations are required to have an arbitrary minimum dictated by the
init. This confuses users and makes configuration more annoying than it
should. An example of this is pids.max, where Go spawns multiple
processes that then cause init to violate the pids cgroup constraint
before the container can even start.
Solve this problem by setting the cgroup configurations as late as
possible, to avoid hitting as many of the resources hogged by the Go
init as possible. This has to be done before seccomp rules are applied,
as the parent and child must synchronise in order for the parent to
correctly set the configurations (and writes might be blocked by seccomp).
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Apply and Set are two separate operations, and it doesn't make sense to
group the two together (especially considering that the bootstrap
process is added to the cgroup as well). The only exception to this is
the memory cgroup, which requires the configuration to be set before
processes can join.
One of the weird cases to deal with is systemd. Systemd sets some of the
cgroup configuration options, but not all of them. Because memory is a
special case, we need to explicitly set memory in the systemd Apply().
Otherwise, the rest can be safely re-applied in .Set() as usual.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Due to the fact that the init is implemented in Go (which seemingly
randomly spawns new processes and loves eating memory), most cgroup
configurations are required to have an arbitrary minimum dictated by the
init. This confuses users and makes configuration more annoying than it
should. An example of this is pids.max, where Go spawns multiple
processes that then cause init to violate the pids cgroup constraint
before the container can even start.
Solve this problem by setting the cgroup configurations as late as
possible, to avoid hitting as many of the resources hogged by the Go
init as possible. This has to be done before seccomp rules are applied,
as the parent and child must synchronise in order for the parent to
correctly set the configurations (and writes might be blocked by seccomp).
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Apply and Set are two separate operations, and it doesn't make sense to
group the two together (especially considering that the bootstrap
process is added to the cgroup as well). The only exception to this is
the memory cgroup, which requires the configuration to be set before
processes can join.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
add bootstrap data to setns process. If we have any bootstrap data then copy it
to the bootstrap process (i.e. nsexec) using the sync pipe. This will allow us
to eventually replace environment variable usage with more structured data
to setup namespaces, write pid/gid map, setgroup etc.
Signed-off-by: Daniel, Dao Quang Minh <dqminh89@gmail.com>
When starting and quering for pids a container can start and exit before
this is set. So set the opts after the process is started and while
libcontainer still has the container's process blocking on the pipe.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This rather naively fixes an error observed where a processes stdio
streams are not written to when there is an error upon starting up the
process, such as when the executable doesn't exist within the
container's rootfs.
Before the "fix", when an error occurred on start, `terminate` is called
immediately, which calls `cmd.Process.Kill()`, then calling `Wait()` on
the process. In some cases when this `Kill` is called the stdio stream
have not yet been written to, causing non-deterministic output. The
error itself is properly preserved but users attached to the process
will not see this error.
With the fix it is just calling `Wait()` when an error occurs rather
than trying to `Kill()` the process first. This seems to preserve stdio.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Alex Fang
W. Trevor King
Daniel, Dao Quang Minh
Christy Perez
Wentao Zhang
Aleksa Sarai
Michael Crosby
Mrunal Patel
Zhang Wei
Crazykev
Wang Long
Yuanhong Peng
Qiang Huang
George Lestaris
Julian Friedman
Tonis Tiigi
Phil Estes
Kenfe-Mickael Laventure
Hushan Jia
Aleksa Sarai
Mrunal Patel
David Calavera
Brian Goff
keloyang