This is useful to optionally set /dev ro,noexec.
Treat /dev and /dev/pts the same as /proc and /sys.
Make sure the Type is right though. Many config.json snippets
on the Internet suggest /dev is tmpfs, not devtmpfs.
Inode number consistency checks are now skipped in save/restore tests for
reasons described in greatest detail in StatTest.StateDoesntChangeAfterRename.
They pass in VFS1 due to the bug described in new test case
SimpleStatTest.DifferentFilesHaveDifferentDeviceInodeNumberPairs.
Fixes#1663
PiperOrigin-RevId: 338776148
Our current reference leak checker uses finalizers to verify whether an object
has reached zero references before it is garbage collected. There are multiple
problems with this mechanism, so a rewrite is in order.
With finalizers, there is no way to guarantee that a finalizer will run before
the program exits. When an unreachable object with a finalizer is garbage
collected, its finalizer will be added to a queue and run asynchronously. The
best we can do is run garbage collection upon sandbox exit to make sure that
all finalizers are enqueued.
Furthermore, if there is a chain of finalized objects, e.g. A points to B
points to C, garbage collection needs to run multiple times before all of the
finalizers are enqueued. The first GC run will register the finalizer for A but
not free it. It takes another GC run to free A, at which point B's finalizer
can be registered. As a result, we need to run GC as many times as the length
of the longest such chain to have a somewhat reliable leak checker.
Finally, a cyclical chain of structs pointing to one another will never be
garbage collected if a finalizer is set. This is a well-known issue with Go
finalizers (https://github.com/golang/go/issues/7358). Using leak checking on
filesystem objects that produce cycles will not work and even result in memory
leaks.
The new leak checker stores reference counted objects in a global map when
leak check is enabled and removes them once they are destroyed. At sandbox
exit, any remaining objects in the map are considered as leaked. This provides
a deterministic way of detecting leaks without relying on the complexities of
finalizers and garbage collection.
This approach has several benefits over the former, including:
- Always detects leaks of objects that should be destroyed very close to
sandbox exit. The old checker very rarely detected these leaks, because it
relied on garbage collection to be run in a short window of time.
- Panics if we forgot to enable leak check on a ref-counted object (we will try
to remove it from the map when it is destroyed, but it will never have been
added).
- Can store extra logging information in the map values without adding to the
size of the ref count struct itself. With the size of just an int64, the ref
count object remains compact, meaning frequent operations like IncRef/DecRef
are more cache-efficient.
- Can aggregate leak results in a single report after the sandbox exits.
Instead of having warnings littered in the log, which were
non-deterministically triggered by garbage collection, we can print all
warning messages at once. Note that this could also be a limitation--the
sandbox must exit properly for leaks to be detected.
Some basic benchmarking indicates that this change does not significantly
affect performance when leak checking is enabled, which is understandable
since registering/unregistering is only done once for each filesystem object.
Updates #1486.
PiperOrigin-RevId: 338685972
Subcontainers are only configured when the container starts, however because
start doesn't load the spec, flag annotations that may override flags were
not getting applied to the configuration.
Updates #3494
PiperOrigin-RevId: 338610953
- Check the sticky bit in overlay.filesystem.UnlinkAt(). Fixes
StickyTest.StickyBitPermDenied.
- When configuring a VFS2 overlay in runsc, copy the lower layer's root
owner/group/mode to the upper layer's root (as in the VFS1 equivalent,
boot.addOverlay()). This makes the overlay root owned by UID/GID 65534 with
mode 0755 rather than owned by UID/GID 0 with mode 01777. Fixes
CreateTest.CreateFailsOnUnpermittedDir, which assumes that the test cannot
create files in /.
- MknodTest.UnimplementedTypesReturnError assumes that the creation of device
special files is not supported. However, while the VFS2 gofer client still
doesn't support device special files, VFS2 tmpfs does, and in the overlay
test dimension mknod() targets a tmpfs upper layer. The test initially has
all capabilities, including CAP_MKNOD, so its creation of these files
succeeds. Constrain these tests to VFS1.
- Rename overlay.nonDirectoryFD to overlay.regularFileFD and only use it for
regular files, using the original FD for pipes and device special files. This
is more consistent with Linux (which gets the original inode_operations, and
therefore file_operations, for these file types from ovl_fill_inode() =>
init_special_inode()) and fixes remaining mknod and pipe tests.
- Read/write 1KB at a time in PipeTest.Streaming, rather than 4 bytes. This
isn't strictly necessary, but it makes the test less obnoxiously slow on
ptrace.
Fixes#4407
PiperOrigin-RevId: 337971042
Using the newer bazel rules necessitates a transition from proto1 to
proto2. In order to resolve the incompatibility between proto2 and
gogoproto, the cri runtimeoptions proto must be vendored.
Further, some of the semantics of bazel caching changed during the
transition. It is now necessary to:
- Ensure that :gopath depends only on pure library targets, as the
propagation of go_binary build attributes (pure, static) will
affected the generated files (though content remains the same,
there are conflicts with respect to the gopath).
- Update bazel.mk to include the possibility of binaries in the
bazel-out directory, as it will now put runsc and others there.
This required some refinements to the mechanism of extracting
paths, since some the existing regex resulted in false positives.
- Change nogo rules to prevent escape generation on binary targets.
For some reason, the newer version of bazel attempted to run the
nogo analysis on the binary targets, which fails due to the fact
that objdump does not work on the final binary. This must be due
to a change in the semantics of aspects in bazel3.
PiperOrigin-RevId: 337958324
When all container tasks finish, they release the mount which in turn
will close the 9P session to the gofer. The gofer exits when the connection
closes, triggering the gofer monitor. The gofer monitor will _think_ that
the gofer died prematurely and destroy the container. Then when the caller
attempts to wait for the container, e.g. to get the exit code, wait fails
saying the container doesn't exist.
Gofer monitor now just SIGKILLs the container, and let the normal teardown
process to happen, which will evetually destroy the container at the right
time. Also, fixed an issue with exec racing with container's init process
exiting.
Closes#1487
PiperOrigin-RevId: 335537350
With cgroups configured NumCPU is correct, however GOMAXPROCS is still derived from total host core count and ignores cgroup restrictions. This can lead to different and undesired behavior across different hosts.
For example, the total number of threads in the guest process will be larger on machines with more cores.
This change configures the go runtime for the sandbox to only use the number of threads consistent with its restrictions.
Network or transport protocols may want to reach the stack. Support this
by letting the stack create the protocol instances so it can pass a
reference to itself at protocol creation time.
Note, protocols do not yet use the stack in this CL but later CLs will
make use of the stack from protocols.
PiperOrigin-RevId: 334260210
https://go.googlesource.com/go/+/0941fc3 switches the Go runtime (on amd64)
from using arch_prctl(ARCH_SET_FS) to CLONE_SETTLS to set the TLS.
PiperOrigin-RevId: 333100550
OCI configuration includes support for specifying seccomp filters. In runc,
these filter configurations are converted into seccomp BPF programs and loaded
into the kernel via libseccomp. runsc needs to be a static binary so, for
runsc, we cannot rely on a C library and need to implement the functionality
in Go.
The generator added here implements basic support for taking OCI seccomp
configuration and converting it into a seccomp BPF program with the same
behavior as a program generated by libseccomp.
- New conditional operations were added to pkg/seccomp to support operations
available in OCI.
- AllowAny and AllowValue were renamed to MatchAny and EqualTo to better reflect
that syscalls matching the conditionals result in the provided action not
simply SCMP_RET_ALLOW.
- BuildProgram in pkg/seccomp no longer panics if provided an empty list of
rules. It now builds a program with the architecture sanity check only.
- ProgramBuilder now allows adding labels that are unused. However, backwards
jumps are still not permitted.
Fixes#510
PiperOrigin-RevId: 331938697
The existing implementation for TransportProtocol.{Set}Option take
arguments of an empty interface type which all types (implicitly)
implement; any type may be passed to the functions.
This change introduces marker interfaces for transport protocol options
that may be set or queried which transport protocol option types
implement to ensure that invalid types are caught at compile time.
Different interfaces are used to allow the compiler to enforce read-only
or set-only socket options.
RELNOTES: n/a
PiperOrigin-RevId: 330559811
VFS1 and VFS2 host FDs have different dupping behavior,
making error prone to code for both. Change the contract
so that FDs are released as they are used, so the caller
can simple defer a block that closes all remaining files.
This also addresses handling of partial failures.
With this fix, more VFS2 tests can be enabled.
Updates #1487
PiperOrigin-RevId: 330112266
Currently the stdio FDs are not dupped and will be closed
unexpectedly in VFS2 when starting a child container. This
patch fixes this issue.
Fixes: #3821
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
The existing implementation for NetworkProtocol.{Set}Option take
arguments of an empty interface type which all types (implicitly)
implement; any type may be passed to the functions.
This change introduces marker interfaces for network protocol options
that may be set or queried which network protocol option types implement
to ensure that invalid types are caught at compile time. Different
interfaces are used to allow the compiler to enforce read-only or
set-only socket options.
PiperOrigin-RevId: 328980359
Use reflection and tags to provide automatic conversion from
Config to flags. This makes adding new flags less error-prone,
skips flags using default values (easier to read), and makes
tests correctly use default flag values for test Configs.
Updates #3494
PiperOrigin-RevId: 328662070
This lets us create "synthetic" mountpoint directories in ReadOnly mounts
during VFS setup.
Also add context.WithMountNamespace, as some filesystems (like overlay) require
a MountNamespace on ctx to handle vfs.Filesystem Operations.
PiperOrigin-RevId: 327874971
Running garbage collection enqueues all finalizers, which are used by the
refs/refs_vfs2 packages to detect reference leaks. Note that even with GC,
there is no guarantee that all finalizers will be run before the program exits.
This is a best effort attempt to activate leak checks as much as possible.
Updates #3545.
PiperOrigin-RevId: 325834438
Earlier we were using NLink to decide if /tmp is empty or not. However, NLink
at best tells us about the number of subdirectories (via the ".." entries).
NLink = n + 2 for n subdirectories. But it does not tell us if the directory is
empty. There still might be non-directory files. We could also not rely on
NLink because host overlayfs always returned 1.
VFS1 uses Readdir to decide if the directory is empty. Used a similar approach.
We now use IterDirents to decide if the "/tmp" directory is empty.
Fixes#3369
PiperOrigin-RevId: 325554234
The loader dup's stdio FD into stable FD's starting at a fixed
number. During tests, it's possible that the target FD is already
in use. Added check to error early so it's easier to debug failures.
Also bumped up the starting FD number to prevent collisions.
PiperOrigin-RevId: 324917299
Now it calls pkt.Data.ToView() when writing the packet. This may require
copying when the packet is large, which puts the worse case in an even worse
situation.
This sent out in a separate preparation change as it requires syscall filter
changes. This change will be followed by the change for the adoption of the new
PacketHeader API.
PiperOrigin-RevId: 321447003
- Combine process creation code that is shared between
root and subcontainer processes
- Move root container information into a struct for
clarity
Updates #2714
PiperOrigin-RevId: 321204798
This change gates all FUSE commands (by gating /dev/fuse) behind a runsc
flag. In order to use FUSE commands, use the --fuse flag with the --vfs2
flag. Check if FUSE is enabled by running dmesg in the sandbox.
gVisor bot
Konstantin Baranov
Jamie Liu
Dean Deng
Fabricio Voznika
Adin Scannell
Ben Buzbee
Ghanan Gowripalan
Michael Pratt
Ian Lewis
Ayush Ranjan
Tiwei Bie
Nicolas Lacasse
Nayana Bidari
Ridwan Sharif
Bhasker Hariharan
Ting-Yu Wang