This reverts part of the commit eb0a144b5e
That commit introduced two issues.
- We need to make parent mount of rootfs private before bind mounting
rootfs. Otherwise bind mounting root can propagate in other mount
namespaces. (If parent mount is shared).
- It broke test TestRootfsPropagationSharedMount() on Fedora.
On fedora /tmp is a mount point with "shared" propagation. I think
you should be able to reproduce it on other distributions as well
as long as you mount tmpfs on /tmp and make it "shared" propagation.
Reason for failure is that pivot_root() fails. And it fails because
kernel does following check.
IS_MNT_SHARED(new_mnt->mnt_parent)
Say /tmp/foo is new rootfs, we have bind mounted rootfs, so new_mnt
is /tmp/foo, and new_mnt->mnt_parent is /tmp which is "shared" on
fedora and above check fails.
So this change broke few things, it is a good idea to revert part of it.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Namely, use an undocumented feature of pivot_root(2) where
pivot_root(".", ".") is actually a feature and allows you to make the
old_root be tied to your /proc/self/cwd in a way that makes unmounting
easy. Thanks a lot to the LXC developers which came up with this idea
first.
This is the first step of many to allowing runC to work with a
completely read-only rootfs.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
If copyup is specified for a tmpfs mount, then the contents of the
underlying directory are copied into the tmpfs mounted over it.
Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
In order to mount root filesystems inside the container's mount
namespace as part of the spec we need to have the ability to do a bind
mount to / as the destination.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
For example, the /sys/firmware directory should be masked because it can contain some sensitive files:
- /sys/firmware/acpi/tables/{SLIC,MSDM}: Windows license information:
- /sys/firmware/ibft/target0/chap-secret: iSCSI CHAP secret
Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
There's no point in changing directory here. Syscalls are resolved local
to the linkpath, not to the current directory that the process was in
when creating the symlink. Changing directories just confuses people who
are trying to debug things.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
Comparisons with paths aren't really a good idea unless you're
guaranteed that the comparison will work will all paths that resolve to
the same lexical path as the compared path.
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>
No substantial code change.
Note that some style errors reported by `golint` are not fixed due to possible compatibility issues.
Signed-off-by: Akihiro Suda <suda.kyoto@gmail.com>
setupDev was introduced in #96, but broken since #536 because spec 0.3.0 introduced default devices.
Fix#80 again
Fixdocker/docker#21808
Signed-off-by: Akihiro Suda <suda.kyoto@gmail.com>
Signed-off-by: Alexander Morozov <lk4d4@docker.com>
This allows the mount syscall to validate the addiontal types where we
do not have to perform extra validation and is up to the consumer to
verify the functionality of the type of device they are trying to
mount.
Fixes#572
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Signed-off-by: rajasec <rajasec79@gmail.com>
Changing to name values for defer as per review comments
Signed-off-by: rajasec <rajasec79@gmail.com>
Fixed review comments
Signed-off-by: rajasec <rajasec79@gmail.com>
Because we more than likely control dev and populate devices and files
inside of it we need to make sure that we fulfil the user's request to
make it ro only after it has been populated. This removes the need to
expose something like ReadonlyPaths in the config but still have the
same outcome but more seemless for the user.
Signed-off-by: Michael Crosby <crosbymichael@gmail.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>
When we launch a container in a new user namespace, we cannot create
devices, so we bind mount the host's devices into place instead.
If we are running in a user namespace (i.e. nested in a container),
then we need to do the same thing. Add a function to detect that
and check for it before doing mknod.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
---
Changelog - add a comment clarifying what's going on with the
uidmap file.
Enables launching userns containers by catching EPERM errors for writing
to devices cgroups, and for mknod invocations.
Signed-off-by: Abin Shahab <ashahab@altiscale.com>
Minor fix, the former setupDev=true means not setup dev,
which is contrary to intuition, just correct it.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Docker pkgs were updated while golinting the whole docker code base.
Now when trying to bump libcontainer/runc in docker, it fails compiling
with the following error:
``
vendor/src/github.com/opencontainers/runc/libcontainer/rootfs_linux.go:424:
undefined: mount.MountInfo
``
This is because, for instance, the mount pkg was updated here
0f5c9d301b (diff-49294d05afa48e2f7c0d2f02c6f7614c)
and now that type is only `mount.Info`.
This patch bump docker pkgs commit and adapt code to it.
Signed-off-by: Antonio Murdaca <amurdaca@redhat.com>
pivotDir is the one where pivot_root() call puts the old root. We will
unmount pivotDir() and delete it.
Previously we were making / always rslave or rprivate. That will mean
that pivotDir() could never have mounts which would be shared with
parent mount namespace. That also means that unmounting pivotDir() was
safe and none of the unmount will propagate to parent namespace and
unmount things which we did not want to.
But now user can specify that apply private, shared, slave on /. That
means some of the mounts we inherited from parent could be shared and that
also means if we umount pivotDir/, those mounts will get unmounted in
parent too. That's not what we want.
Instead make pivotDir rprivate so that unmounts don't propagate back to
parent.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
pivot_root() introduces bunch of restrictions otherwise it fails. parent
mount of container root can not be shared otherwise pivot_root() will
fail.
So far parent could not be shared as we marked everything either private
or slave. But now we have introduced new propagation modes where parent
mount of container rootfs could be shared and pivot_root() will fail.
So check if parent mount is shared and if yes, make it private. This will
make sure pivot_root() works.
Also it will make sure that when we bind mount container rootfs, it does
not propagate to parent mount namespace. Otherwise cleanup becomes a
problem.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Right now config.Privatefs is a boolean which determines if / is applied
with propagation flag syscall.MS_PRIVATE | syscall.MS_REC or not.
Soon we want to represent other propagation states like private, [r]slave,
and [r]shared. So either we can introduce more boolean variable or keep
track of propagation flags in an integer variable. Keeping an integer
variable is more versatile and can allow various kind of propagation flags
to be specified. So replace Privatefs with RootPropagation which is an
integer.
Note, this will require changes in docker. Instead of setting Privatefs
to true, they will need to set.
config.RootPropagation = syscall.MS_PRIVATE | syscall.MS_REC
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Do not remount a bind mount to enable flags unless non-default flags are
provided for the requested mount. This solves a problem with user
namespaces and remount of bind mount permissions.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Do not have methods and actions that require syscalls in the configs
package because it breaks cross compile.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
We need to update the mount's destination after we resolve symlinks so
that it properly creates and mounts the correct location.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Vivek Goyal
Aleksa Sarai
Alexander Morozov
Daniel Dao
Mrunal Patel
Michael Crosby
Akihiro Suda
Serge Hallyn
Haiyan Meng
Aleksa Sarai
Dan Walsh
Tatsushi Inagaki
Akihiro Suda
Thomas Tanaka
Mrunal Patel
rajasec
Chun Chen
Kenfe-Mickael Laventure
Serge Hallyn
Qiang Huang
Abin Shahab
Antonio Murdaca
Phil Estes