Ensure data-race-free access to the daemon configuration without
locking by mutating a deep copy of the config and atomically storing
a pointer to the copy into the daemon-wide configStore value. Any
operations which need to read from the daemon config must capture the
configStore value only once and pass it around to guarantee a consistent
view of the config.
Signed-off-by: Cory Snider <csnider@mirantis.com>
If the file doesn't exist, the process isn't running, so we should be able
to ignore that.
Also remove an intermediate variable.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Do not use 0701 perms.
0701 dir perms allows anyone to traverse the docker dir.
It happens to allow any user to execute, as an example, suid binaries
from image rootfs dirs because it allows traversal AND critically
container users need to be able to do execute things.
0701 on lower directories also happens to allow any user to modify
things in, for instance, the overlay upper dir which neccessarily
has 0755 permissions.
This changes to use 0710 which allows users in the group to traverse.
In userns mode the UID owner is (real) root and the GID is the remapped
root's GID.
This prevents anyone but the remapped root to traverse our directories
(which is required for userns with runc).
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit ef7237442147441a7cadcda0600be1186d81ac73)
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit 93ac040bf0)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
The io/ioutil package has been deprecated in Go 1.16. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
After moving libnetwork to this repo, we need to update all the import
paths for libnetwork to point to docker/docker/libnetwork instead of
docker/libnetwork.
This change implements that.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Various dirs in /var/lib/docker contain data that needs to be mounted
into a container. For this reason, these dirs are set to be owned by the
remapped root user, otherwise there can be permissions issues.
However, this uneccessarily exposes these dirs to an unprivileged user
on the host.
Instead, set the ownership of these dirs to the real root (or rather the
UID/GID of dockerd) with 0701 permissions, which allows the remapped
root to enter the directories but not read/write to them.
The remapped root needs to enter these dirs so the container's rootfs
can be configured... e.g. to mount /etc/resolve.conf.
This prevents an unprivileged user from having read/write access to
these dirs on the host.
The flip side of this is now any user can enter these directories.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit e908cc3901)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
`os.RemoveAll()` should never return this error. From the docs:
> If the path does not exist, RemoveAll returns nil (no error).
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This came up in a review of a5324d6950, but
for some reason that comment didn't find its way to GitHub, and/or I
forgot to push the change.
These files are "copied" by reading their content with ioutil.Readfile(),
resolving the symlinks should therefore not be needed, and paths can be
passed as-is;
```go
func copyFile(src, dst string) error {
sBytes, err := ioutil.ReadFile(src)
if err != nil {
return err
}
return ioutil.WriteFile(dst, sBytes, filePerm)
}
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Commit e353e7e3f0 updated selection of the
`resolv.conf` file to use in situations where systemd-resolvd is used as
a resolver.
If a host uses `systemd-resolvd`, the system's `/etc/resolv.conf` file is
updated to set `127.0.0.53` as DNS, which is the local IP address for
systemd-resolvd. The DNS servers that are configured by the user will now
be stored in `/run/systemd/resolve/resolv.conf`, and systemd-resolvd acts
as a forwarding DNS for those.
Originally, Docker copied the DNS servers as configured in `/etc/resolv.conf`
as default DNS servers in containers, which failed to work if systemd-resolvd
is used (as `127.0.0.53` is not available inside the container's networking
namespace). To resolve this, e353e7e3f0 instead
detected if systemd-resolvd is in use, and in that case copied the "upstream"
DNS servers from the `/run/systemd/resolve/resolv.conf` configuration.
While this worked for most situations, it had some downsides, among which:
- we're skipping systemd-resolvd altogether, which means that we cannot take
advantage of addition functionality provided by it (such as per-interface
DNS servers)
- when updating DNS servers in the system's configuration, those changes were
not reflected in the container configuration, which could be problematic in
"developer" scenarios, when switching between networks.
This patch changes the way we select which resolv.conf to use as template
for the container's resolv.conf;
- in situations where a custom network is attached to the container, and the
embedded DNS is available, we use `/etc/resolv.conf` unconditionally. If
systemd-resolvd is used, the embedded DNS forwards external DNS lookups to
systemd-resolvd, which in turn is responsible for forwarding requests to
the external DNS servers configured by the user.
- if the container is running in "host mode" networking, we also use the
DNS server that's configured in `/etc/resolv.conf`. In this situation, no
embedded DNS server is available, but the container runs in the host's
networking namespace, and can use the same DNS servers as the host (which
could be systemd-resolvd or DNSMasq
- if the container uses the default (bridge) network, no embedded DNS is
available, and the container has its own networking namespace. In this
situation we check if systemd-resolvd is used, in which case we skip
systemd-resolvd, and configure the upstream DNS servers as DNS for the
container. This situation is the same as is used currently, which means
that dynamically switching DNS servers won't be supported for these
containers.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Switch to moby/sys/mount and mountinfo. Keep the pkg/mount for potential
outside users.
This commit was generated by the following bash script:
```
set -e -u -o pipefail
for file in $(git grep -l 'docker/docker/pkg/mount"' | grep -v ^pkg/mount); do
sed -i -e 's#/docker/docker/pkg/mount"#/moby/sys/mount"#' \
-e 's#mount\.\(GetMounts\|Mounted\|Info\|[A-Za-z]*Filter\)#mountinfo.\1#g' \
$file
goimports -w $file
done
```
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This changes the default ipc mode of daemon/engine to be private,
meaning the containers will not have their /dev/shm bind-mounted
from the host by default. The benefits of doing this are:
1. No leaked mounts. Eliminate a possibility to leak mounts into
other namespaces (and therefore unfortunate errors like "Unable to
remove filesystem for <ID>: remove /var/lib/docker/containers/<ID>/shm:
device or resource busy").
2. Working checkpoint/restore. Make `docker checkpoint`
not lose the contents of `/dev/shm`, but save it to
the dump, and be restored back upon `docker start --checkpoint`
(currently it is lost -- while CRIU handles tmpfs mounts,
the "shareable" mount is seen as external to container,
and thus rightfully ignored).
3. Better security. Currently any container is opened to share
its /dev/shm with any other container.
Obviously, this change will break the following usage scenario:
$ docker run -d --name donor busybox top
$ docker run --rm -it --ipc container:donor busybox sh
Error response from daemon: linux spec namespaces: can't join IPC
of container <ID>: non-shareable IPC (hint: use IpcMode:shareable
for the donor container)
The soution, as hinted by the (amended) error message, is to
explicitly enable donor sharing by using --ipc shareable:
$ docker run -d --name donor --ipc shareable busybox top
Compatibility notes:
1. This only applies to containers created _after_ this change.
Existing containers are not affected and will work fine
as their ipc mode is stored in HostConfig.
2. Old backward compatible behavior ("shareable" containers
by default) can be enabled by either using
`--default-ipc-mode shareable` daemon command line option,
or by adding a `"default-ipc-mode": "shareable"`
line in `/etc/docker/daemon.json` configuration file.
3. If an older client (API < 1.40) is used, a "shareable" container
is created. A test to check that is added.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
The Swarmkit api specifies a target for configs called called "Runtime"
which indicates that the config is not mounted into the container but
has some other use. This commit updates the Docker api to reflect this.
Signed-off-by: Drew Erny <drew.erny@docker.com>
When running a container in the host's network namespace, the container
gets a copy of the host's resolv.conf (copied to `/etc/resolv.conf` inside
the container).
The current code always used the default (`/etc/resolv.conf`) path on the
host, irregardless if `systemd-resolved` was used or not.
This patch uses the correct file if `systemd-resolved` was detected
to be running.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
As standard mount.Unmount does what we need, let's use it.
In addition, this adds ignoring "not mounted" condition, which
was previously implemented (see PR#33329, commit cfa2591d3f)
via a very expensive call to mount.Mounted().
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This implements chown support on Windows. Built-in accounts as well
as accounts included in the SAM database of the container are supported.
NOTE: IDPair is now named Identity and IDMappings is now named
IdentityMapping.
The following are valid examples:
ADD --chown=Guest . <some directory>
COPY --chown=Administrator . <some directory>
COPY --chown=Guests . <some directory>
COPY --chown=ContainerUser . <some directory>
On Windows an owner is only granted the permission to read the security
descriptor and read/write the discretionary access control list. This
fix also grants read/write and execute permissions to the owner.
Signed-off-by: Salahuddin Khan <salah@docker.com>
Handle the case of systemd-resolved, and if in place
use a different resolv.conf source.
Set appropriately the option on libnetwork.
Move unix specific code to container_operation_unix
Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>
On unix, merge secrets/configs handling. This is important because
configs can contain secrets (via templating) and potentially a config
could just simply have secret information "by accident" from the user.
This just make sure that configs are as secure as secrets and de-dups a
lot of code.
Generally this makes everything simpler and configs more secure.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
This fix tries to address the issue raised in 36042
where secret and config are not configured with the
specified file mode.
This fix update the file mode so that it is not impacted
with umask.
Additional tests have been added.
This fix fixes 36042.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
It's a common scenario for admins and/or monitoring applications to
mount in the daemon root dir into a container. When doing so all mounts
get coppied into the container, often with private references.
This can prevent removal of a container due to the various mounts that
must be configured before a container is started (for example, for
shared /dev/shm, or secrets) being leaked into another namespace,
usually with private references.
This is particularly problematic on older kernels (e.g. RHEL < 7.4)
where a mount may be active in another namespace and attempting to
remove a mountpoint which is active in another namespace fails.
This change moves all container resource mounts into a common directory
so that the directory can be made unbindable.
What this does is prevents sub-mounts of this new directory from leaking
into other namespaces when mounted with `rbind`... which is how all
binds are handled for containers.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Instead of having to create a bunch of custom error types that are doing
nothing but wrapping another error in sub-packages, use a common helper
to create errors of the requested type.
e.g. instead of re-implementing this over and over:
```go
type notFoundError struct {
cause error
}
func(e notFoundError) Error() string {
return e.cause.Error()
}
func(e notFoundError) NotFound() {}
func(e notFoundError) Cause() error {
return e.cause
}
```
Packages can instead just do:
```
errdefs.NotFound(err)
```
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Without relabel these files, SELinux-enabled containers will show
"permission denied" errors for configuration files mounted with
`docker server create ... --config ... ...`.
Signed-off-by: Wenxuan Zhao <viz@linux.com>
Use strongly typed errors to set HTTP status codes.
Error interfaces are defined in the api/errors package and errors
returned from controllers are checked against these interfaces.
Errors can be wraeped in a pkg/errors.Causer, as long as somewhere in the
line of causes one of the interfaces is implemented. The special error
interfaces take precedence over Causer, meaning if both Causer and one
of the new error interfaces are implemented, the Causer is not
traversed.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Since the commit d88fe447df ("Add support for sharing /dev/shm/ and
/dev/mqueue between containers") container's /dev/shm is mounted on the
host first, then bind-mounted inside the container. This is done that
way in order to be able to share this container's IPC namespace
(and the /dev/shm mount point) with another container.
Unfortunately, this functionality breaks container checkpoint/restore
(even if IPC is not shared). Since /dev/shm is an external mount, its
contents is not saved by `criu checkpoint`, and so upon restore any
application that tries to access data under /dev/shm is severily
disappointed (which usually results in a fatal crash).
This commit solves the issue by introducing new IPC modes for containers
(in addition to 'host' and 'container:ID'). The new modes are:
- 'shareable': enables sharing this container's IPC with others
(this used to be the implicit default);
- 'private': disables sharing this container's IPC.
In 'private' mode, container's /dev/shm is truly mounted inside the
container, without any bind-mounting from the host, which solves the
issue.
While at it, let's also implement 'none' mode. The motivation, as
eloquently put by Justin Cormack, is:
> I wondered a while back about having a none shm mode, as currently it is
> not possible to have a totally unwriteable container as there is always
> a /dev/shm writeable mount. It is a bit of a niche case (and clearly
> should never be allowed to be daemon default) but it would be trivial to
> add now so maybe we should...
...so here's yet yet another mode:
- 'none': no /dev/shm mount inside the container (though it still
has its own private IPC namespace).
Now, to ultimately solve the abovementioned checkpoint/restore issue, we'd
need to make 'private' the default mode, but unfortunately it breaks the
backward compatibility. So, let's make the default container IPC mode
per-daemon configurable (with the built-in default set to 'shareable'
for now). The default can be changed either via a daemon CLI option
(--default-shm-mode) or a daemon.json configuration file parameter
of the same name.
Note one can only set either 'shareable' or 'private' IPC modes as a
daemon default (i.e. in this context 'host', 'container', or 'none'
do not make much sense).
Some other changes this patch introduces are:
1. A mount for /dev/shm is added to default OCI Linux spec.
2. IpcMode.Valid() is simplified to remove duplicated code that parsed
'container:ID' form. Note the old version used to check that ID does
not contain a semicolon -- this is no longer the case (tests are
modified accordingly). The motivation is we should either do a
proper check for container ID validity, or don't check it at all
(since it is checked in other places anyway). I chose the latter.
3. IpcMode.Container() is modified to not return container ID if the
mode value does not start with "container:", unifying the check to
be the same as in IpcMode.IsContainer().
3. IPC mode unit tests (runconfig/hostconfig_test.go) are modified
to add checks for newly added values.
[v2: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-51345997]
[v3: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-53902833]
[v4: addressed the case of upgrading from older daemon, in this case
container.HostConfig.IpcMode is unset and this is valid]
[v5: document old and new IpcMode values in api/swagger.yaml]
[v6: add the 'none' mode, changelog entry to docs/api/version-history.md]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
It was noted[1] that container's HostConfig.ShmSize, if not set, should be
initialized to daemon default value during container creation.
In fact, it is already done in daemon.adaptContainerSettings, so we can use
value from container.HostConfig directly.
[1] https://github.com/moby/moby/pull/34087#discussion_r128656429
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
