Linux kernel before 4.19 doesn't implement a feature that updates
open FD after a file is open for write (and is copied to the upper
layer). Already open FD will continue to read the old file content
until they are reopened. This is especially problematic for gVisor
because it caches open files.
Flag was added to force readonly files to be reopenned when the
same file is open for write. This is only needed if using kernels
prior to 4.19.
Closes#1006
It's difficult to really test this because we never run on tests
on older kernels. I'm adding a test in GKE which uses kernels
with the overlayfs problem for 1.14 and lower.
PiperOrigin-RevId: 275115289
Filter installation has been streamlined and functions renamed.
Documentation has been fixed to be standards compliant, and missing
documentation added. gofmt has also been applied to modified files.
When we reopen file by path, we can't be sure that
we will open exactly the same file. The file can be
deleted and another one with the same name can be
created.
PiperOrigin-RevId: 254898594
Based on the guidelines at
https://opensource.google.com/docs/releasing/authors/.
1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./'
2. Manual fixup of "Google Inc" references.
3. Add AUTHORS file. Authors may request to be added to this file.
4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS.
Fixes#209
PiperOrigin-RevId: 245823212
Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
Properly handle propagation options for root and mounts. Now usage of
mount options shared, rshared, and noexec cause error to start. shared/
rshared breaks sandbox=>host isolation. slave however can be supported
because changes propagate from host to sandbox.
Root FS setup moved inside the gofer. Apart from simplifying the code,
it keeps all mounts inside the namespace. And they are torn down when
the namespace is destroyed (DestroyFS is no longer needed).
PiperOrigin-RevId: 239037661
Change-Id: I8b5ee4d50da33c042ea34fa68e56514ebe20e6e0
Removed "error" and "failed to" prefix that don't add value
from messages. Adjusted a few other messages. In particular,
when the container fail to start, the message returned is easier
for humans to read:
$ docker run --rm --runtime=runsc alpine foobar
docker: Error response from daemon: OCI runtime start failed: <path> did not terminate sucessfully: starting container: starting root container [foobar]: starting sandbox: searching for executable "foobar", cwd: "/", $PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin": no such file or directory
Closes#77
PiperOrigin-RevId: 230022798
Change-Id: I83339017c70dae09e4f9f8e0ea2e554c4d5d5cd1
Otherwise the gofer's attach point may be different from sandbox when there
symlinks in the path.
PiperOrigin-RevId: 219730492
Change-Id: Ia9c4c2d16228c6a1a9e790e0cb673fd881003fe1
With recent changes to 9P server, path walks are now safe inside
open, create, rename and setattr calls. To simplify the code, remove
the lazyopen=false mode that was used for bind mounts, and converge
all mounts to using lazy open.
PiperOrigin-RevId: 219508628
Change-Id: I073e7e1e2e9a9972d150eaf4cb29e553997a9b76
Capabilities.Set() adds capabilities,
but doesn't remove existing ones that might have been loaded. Fixed
the code and added tests.
PiperOrigin-RevId: 213726369
Change-Id: Id7fa6fce53abf26c29b13b9157bb4c6616986fba
Now each container gets its own dedicated gofer that is chroot'd to the
rootfs path. This is done to add an extra layer of security in case the
gofer gets compromised.
PiperOrigin-RevId: 210396476
Change-Id: Iba21360a59dfe90875d61000db103f8609157ca0
This is used when '--overlay=true' to guarantee writes are not sent to gofer.
PiperOrigin-RevId: 210116288
Change-Id: I7616008c4c0e8d3668e07a205207f46e2144bf30
When multiple containers run inside a sentry, each container has its own root
filesystem and set of mounts. Containers are also added after sentry boot rather
than all configured and known at boot time.
The fsgofer needs to be able to serve the root filesystem of each container.
Thus, it must be possible to add filesystems after the fsgofer has already
started.
This change:
* Creates a URPC endpoint within the gofer process that listens for requests to
serve new content.
* Enables the sentry, when starting a new container, to add the new container's
filesystem.
* Mounts those new filesystems at separate roots within the sentry.
PiperOrigin-RevId: 208903248
Change-Id: Ifa91ec9c8caf5f2f0a9eead83c4a57090ce92068