- Omit the redundant `v8` variant for arm64 when rendering
`description`, so equal arm64 platforms always describe as
`linux/arm64` — matching how Docker and containerd display
the platform. Other variants (`arm/v7`) and architectures
(`amd64`) are unaffected.
- Only the rendered `description` changes. The stored `variant`
and the `Codable` encoding are untouched, so OCI content
digests remain stable.
- Closesapple/container#1542 (normalization-consistency aspect).
This fixes a latent bug in the `Platform` types equality operator where
two platforms with differing OS's would be treated as the same if they
both had variant set to 'v8' or nil
Fixes#518.
## What
vminitd logs the full OCI spec and exec process at debug level in
`ManagedContainer` ("created bundle with spec …", "creating exec process
with …"), which puts every `NAME=value` environment entry into the boot
log. Environment variables routinely carry secrets, so `container logs
--boot web | grep PASSWORD` reproduces the leak exactly as described in
#518.
Rather than redacting at the call sites, this makes the redacted form
the *default* rendering of the types that own an environment: `Process`
and `Hook` conform to `CustomStringConvertible` with values masked and
names kept. `Spec` and `Hooks` inherit it, because Swift's
reflection-based description renders a nested value through that value's
own `description`.
The effect is that any `\(spec)` or `\(process)` is safe without the
author knowing this file exists, which is what stops a log line added
later from reintroducing the leak. The two existing log sites are
unchanged, so this no longer touches vminitd at all.
Two details worth calling out:
- **`Codable` is untouched.** `description` governs text rendering only,
so an encoded spec still carries the real values and nothing changes
about what is written to disk or sent to the guest. The unredacted
environment also remains available to callers through `process.env`.
- **`description` renders through a mirror** rather than a hand-written
field list. `Process` has 13 fields; listing them by hand would drop the
rest from the log line and would rot as fields are added.
## Verification
- New `SpecRedactionTests` (9 tests) cover: a whole `Spec` interpolated
into a log line never renders the values; `String(describing:)` and
`String(reflecting:)` are redacted too; variable names survive;
`NAME`-only inherit entries pass through; `NAME=` and values containing
further `=` are masked whole; encoding round-trips with the real values;
rendering does not mutate; and the other fields are still rendered.
- Negative control: with the redaction disabled the suite fails with 13
issues, and the output shows the secret in the clear, reproducing #518.
- Full `ContainerizationOCITests` passes, 58 tests in 9 suites.
- `swift format lint --strict --configuration .swift-format-nolint` is
clean, and `swift format` leaves both files unchanged.
Every line here is one I can explain and justify; the reasoning above is
the complete rationale for each change.
- `FileTree.lookup` resolved each path component by linearly scanning the
node's `children` array. This changes the node's child storage to an
`OrderedDictionary<String, Ptr<FileTreeNode>>` (from swift-collections,
which is already a package dependency) keyed by name, so `lookup`
resolves each component in O(1) while iteration keeps the existing
insertion order.
- Little or no difference in unpack time for images with ~10k files, significant
improvement for images with ~100k files or more.
Changes the default Linux capability set for container processes from
`.allCapabilities` to `.defaultOCICapabilities`, making the library
secure-by-default. Callers that genuinely need elevated capabilities
must now opt in explicitly.
Signed-off-by: michael_crosby <michael_crosby@apple.com>
apple/containerization currently runs containers in per-container VMs on
macOS hosts via Virtualization.framework. This adds a second VMM backend
so the same Swift orchestration layer (LinuxContainer / LinuxPod /
Vminitd gRPC contract) runs on Linux hosts via cloud-hypervisor + KVM.
**CloudHypervisor Swift package** (`Sources/CloudHypervisor/`) — a thin
client for cloud-hypervisor's REST-over-UDS API, layered on
AsyncHTTPClient. Endpoints cover VMM / VM lifecycle / hotplug (disk, fs,
net, vsock, remove-device). Cross-platform (compiles on macOS for unit
tests; consumed at runtime only by the Linux side of Containerization).
**CH backend in Containerization** — one cloud-hypervisor subprocess per
VM, gated behind `#if os(Linux)`. CHVirtualMachineManager /
CHVirtualMachineInstance mirror the VZ shape behind the existing
VirtualMachineManager / VirtualMachineInstance protocol. CHProcess and
VirtiofsdProcess manage the binaries; CHHotplugProvider handles
virtio-blk and virtio-fs runtime hotplug (with one virtiofsd per unique
source-hash tag, refcounted across containers).
**Linux host networking** — BridgeManager brings up a Linux bridge with
an IPv4 subnet and (opt-in via `--enable-nat`) iptables MASQUERADE +
scoped FORWARD rules. LinuxBridgedNetwork enslaves a fresh TAP per
container to the bridge. State is recorded under `/run/containerization`
so `cctl bridge delete` reverses exactly what create did. Bridge
teardown verifies the link kind via sysfs to refuse deleting non-bridge
interfaces.
**cctl run / bridge** — end-to-end Linux container run path (image pull,
ext4 rootfs assembly, VM boot, container exec) plus `cctl bridge
create|delete` for the host network plumbing.
**Build & dist** — `make linux-build` / `make linux-integration` build
and exercise the host side inside an apple/container `--virtualization`
dev container. `make dist-x86_64` produces a deployment tarball (cctl +
cloud-hypervisor + virtiofsd + initfs + kernel) cross-compiled from the
aarch64 dev container; pipeline documented in `docs/x86_64-build.md`.
Static-musl C deps and the Zig cross compiler are pinned by SHA256.
The host orchestrator runs as root. Per-VM runtime state lives under
`/run/containerization/ch/<UUID>` with mode 0700; UDS sockets inside are
bound with mode 0600. Vminitd's gRPC channel inherits that trust
boundary — socket-file perms are the auth.
Sandbox flags are upstream-secure by default. Two per-component opt-outs
exist for the apple/container dev-container case (where the host seccomp
profile SIGSYS-kills CH and virtiofsd):
- `CONTAINERIZATION_NO_CH_SECCOMP=1` — `cloud-hypervisor --seccomp
false`.
- `CONTAINERIZATION_NO_VIRTIOFSD_SANDBOX=1` — `virtiofsd --sandbox
none`. Each emits a one-shot `logger.warning` at process start. Legacy
alias `CONTAINERIZATION_RELAXED_SANDBOX=1` flips both. cctl spawns both
binaries with `setsid` and a minimal env allowlist (PATH / HOME /
RUST_LOG / RUST_BACKTRACE) so the parent's secrets don't leak to
children.
`make linux-integration` runs the cross-platform integration suite
against a real cloud-hypervisor VM inside the dev container. Linux runs
the cross-platform subset (`process true`/`false`/`echo hi`, virtiofs
round-trip, hotplug); the macOS suite is unchanged.
Signed-off-by: michael_crosby <michael_crosby@apple.com>
The `PodVolume` type in `LinuxPod` only defined the `nbd` enum value -
however, disk based images are also supported and the pattern is
essentially the same
Signed-off-by: Aditya Ramani <a_ramani@apple.com>
When unpacking an OCI/tar layer, create() already creates missing parent
directories recursively, so regular files and symlinks with absent
parent entries unpack correctly. link() did not, so a hardlink whose
parent directory had no explicit archive entry failed with "<path> not
found" (e.g. images produced by Bazel rules_img). Mirror create()'s
implicit parent creation in link() so such layers unpack, matching
Docker/containerd.
Adds a direct link() unit test and an end-to-end unpack regression test
covering a hardlink, regular file, and symlink with no explicit parent.
Fixes https://github.com/apple/container/issues/1797
The `--log-level` option when running the agent sub-command for vminitd
was being silently ignored cause of the way the agent is being run. As a
workaround we need to read `/proc/self/cmdline` to get the right args
## Summary
`Platform.==` treats `arm64` with `nil` variant as equal to `arm64/v8`,
but `hash(into:)` used `description` which serializes them differently
(`linux/arm64` vs `linux/arm64/v8`). This violates the `Hashable`
contract — equal values must produce the same hash.
### Root cause
```swift
// == returns true for these two
let a = Platform(arch: "arm64", os: "linux", variant: nil)
let b = Platform(arch: "arm64", os: "linux", variant: "v8")
a == b // true ✓
// but hash was different — broken
a.hashValue == b.hashValue // false ✗ (before this fix)
```
This mismatch caused `Set<Platform>` and `Dictionary<Platform, ...>`
lookups to silently miss entries when one platform was decoded from JSON
(no `variant` field in the manifest) and another was created via
`Platform(from:)` or `Platform.current` (which both set `variant =
"v8"`).
### Practical consequence
In `apple/container`, this manifests as inconsistent platform-string
normalization across stages of a single `container build` — some stages
log `linux/arm64`, others `linux/arm64/v8` — which can cause `COPY
--from=<stage>` to fail to resolve the source stage under concurrent
builds. See apple/container#1542.
### Fix
`hash(into:)` now normalizes `arm64` with `nil` variant to `"v8"` before
hashing, matching the existing `==` behavior.
Extends the network plumbing to support per-interface IPv6 address
configuration.
The `Interface` protocol supports `ipv6Address` and `ipv6Gateway`.
The agent's networking RPCs carry per-family fields via new
`InterfaceAddress`, `LinkRoute`, and `DefaultRoute` types in
`ContainerizationExtras`.
`NetlinkSession` adds IPv6 methods for address and route operations.
---------
Co-authored-by: michael_crosby <michael_crosby@apple.com>
Co-authored-by: Michael Crosby <crosbymichael@gmail.com>
This PR adds `totalAllocatedSize()` to the `ContentStore` protocol so it
can be used to get the on-disk footprint without reaching past the
abstraction. `LocalContentStore` implements it by walking its base path,
covering both committed blobs and active ingest sessions.
- Closes#712.
- Replace synchronous `write()` calls in
`BidirectionalRelay` with non-blocking I/O
and `DispatchSourceWrite` backpressure
handling. Under concurrent vsock proxy load,
a single blocked write on the shared serial
dispatch queue would freeze all relay
connections permanently, including unrelated
new connections.
- Set relay file descriptors to `O_NONBLOCK`
and handle `EAGAIN` by suspending reads and
installing a write source to drain pending data.
- Give each `BidirectionalRelay` its own serial queue
instead of sharing one from `UnixSocketRelayManager`,
eliminating cross-connection blocking.
- Resume suspended read sources before cancelling
in `stop()` — GCD does not deliver cancel handlers
on suspended dispatch sources, which caused file
descriptor and memory leaks on teardown under
backpressure.
- Guard-unwrap `buf.baseAddress` in
`drainPendingWrite`.
- Closes#744
- Adds the initial `FilePathOps` utility type
- Adds the `absolutePath` implementation
- Adds the `FilePathOpsTests` file and initial test cases
The `IPv4Address(_ bytes: [UInt8])` initializer in
ContainerizationExtras shifts the third octet by 16 bits instead of 8:
```swift
self.value =
(UInt32(bytes[0]) << 24)
| (UInt32(bytes[1]) << 16)
| (UInt32(bytes[2]) << 16) // should be << 8
| UInt32(bytes[3])
```
Because `bytes[2]` lands in the same bit range as `bytes[1]`, the second
octet gets corrupted by the OR, the third octet is dropped, and bits 8
through 15 are always left zero. Concretely, decoding `[192, 168, 1, 1]`
yields `192.169.0.1` instead of `192.168.1.1`, and `[18, 52, 86, 120]`
yields `18.118.0.120` instead of `18.52.86.120`.
This went unnoticed because the `bytes` computed property getter uses
the correct `>> 8` for the third octet, but there was no test exercising
the byte-array initializer, so the encode and decode paths were never
checked against each other. The sibling `IPv6Address(_ bytes:)`
initializer uses the correct descending shifts (`<< 120, << 112, ... <<
8, << 0`), which is what the IPv4 version should mirror.
The fix changes the third octet shift to 8 bits so the initializer is
the exact inverse of the `bytes` property. I also added two tests to the
initializer suite: a valid-input test that asserts both the resulting
`value` and that `init(bytes).bytes == bytes` round-trips, and an
invalid-length test. The round-trip test fails on the current code and
passes with the fix.
Verification: `swift test --filter ContainerizationExtrasTests` passes
221 tests in 26 suites (the IPv4Address suite goes from 23 to 25 tests).
The new round-trip test fails before the one-line change and passes
after.
Signed-off-by: Aditya Singh <adisin650@gmail.com>
- Closes#749.
- ExportOperation hardcoded the pushed index descriptor's
mediaType to the OCI image index type. RegistryClient.push
uses that descriptor's mediaType as the HTTP Content-Type
header. When the source index was in
Docker manifest.list.v2+json format (the common case for
images pulled from Docker Hub and other public registries),
the body's embedded mediaType field disagreed with the
header, and OCI registries rejected the index PUT with
HTTP 400 MANIFEST_INVALID.
- Use the source index's mediaType for the pushed descriptor
so the header always matches the body. Per-architecture
child manifests are unaffected because they were already
pushed with their actual mediaType.
- Add a parameterized unit test for ExportOperation.export
covering both Docker manifest.list
- Closes#745.
- Facilitates TOCTOU-safe recursion over directory contents.
- Replace FileDescriptor extensions with a static utility type to
prevent potential namespacing issues as this project and Swift evolve.
This PR refactors `ArchiveWriter` to add an API `archive(_ paths:
base:)`. This API is used to archive the contents at each path
independently, similar to doing `tar -cvf archive.tar foo.bin
/bar/baz.txt`.
This issue doesn't affect any of our existing products. This is a
preemptive fix for downstream consumers of EXT4.format where, in some
platforms, leading `//` in the path could get resolved into a FileTree
that looks like this
```sh
/
└── /
└── usr
```
This change adds support for attaching network block device (NBD) to
both LinuxContainer and LinuxPod.
For LinuxContainer, whether to use the underlying
`VZNetworkBlockDeviceStorageDeviceAttachment` is determined by the URL
of the container Mount source.
For LinuxPod, adds additional API to support pod-level volumes that can
be mounted into multiple containers. The PodVolume type provides enum to
support multiple types of volume source. LinuxContainer can reference
the pod level volume using the `Mount.sharedMount()` constructor with
the name referencing the name of the pod volume. This will allow the NBD
to be attached to the pod at the VM level and then bind-mounted into the
container.
For integration tests, added a lightweight NBD server implementation in
swift that speaks the NBD protocol to ensure there is sufficient
coverage for the changes introduced.
Apple Virtualization NBD support documentation:
https://developer.apple.com/documentation/virtualization/vznetworkblockdevicestoragedeviceattachment
- Closes#671.
- Adds optional journal parameter to `EXT4.Formatter.init()`, with nil
default specifying the current no-journal filesystem configuration.
Otherwise the parameter value contains the journal size and mode.
- `minDiskSize` parameter for formatter init specifies the minimum
usable capacity of the resulting filesystem. The resulting disk image
grows past this value to accommodate the filesystem on-disk structures,
including the journal if specified.
Now that we can run this project on linux, lets add some unit tests for
the surfaces that don't..
This additionally changes delete to throw in most cases. I don't really
see how masking these errors is ideal.
Closes#606
This lets the unit tests be runnable on linux. The change:
- Adds a linux-test makefile target so we can run the unit tests locally
- Fixes up some test code to work on Linux (mostly ifdefs)
- Runs the unit tests in CI now
- Fixes a hardlink count decrement threshold
- Fixes unlinking not freeing the first inode
Resolves the failing added tests:
```
✘ Test hardlinkLinksCount() recorded an issue at TestEXT4Format+Link.swift:43:9: Expectation failed: try EXT4.EXT4Reader(blockDevice: afterUnlink).stat("/original").inode.linksCount == 1
✘ Test hardlinkLinksCount() failed after 0.016 seconds with 1 issue.
```
```
✘ Test unlinkFirstInodeFreesInode() recorded an issue at TestEXT4Format+Link.swift:58:9: Expectation failed: try EXT4.EXT4Reader(blockDevice: path).superBlock.freeInodesCount == EXT4.EXT4Reader(blockDevice: emptyPath).superBlock.freeInodesCount
✘ Test unlinkFirstInodeFreesInode() failed after 0.014 seconds with 1 issue.
```
Fixes the `xattr` read loop bounds. Resolves the failing added tests:
> ✘ Test lastXattrNotDroppedAtBufferBoundary() recorded an issue at
TestEXT4ExtendedAttributes.swift:72:13: Expectation failed: (attrs.count
→ 0) == 1
> ✘ Test lastXattrNotDroppedAtBufferBoundary() failed after 0.001
seconds with 1 issue.
> Swift/Array.swift:430: Fatal error: Array index is out of range
Removes the incorrect check for visited inodes. Fixes the added failing
tests:
> ✘ Test sameAbsoluteSymlinkFollowedTwice() recorded an issue at
TestEXT4Reader+IO.swift:502:6: Caught error: symlink loop while
resolving: target/../symlink/file.txt
> ✘ Test sameAbsoluteSymlinkFollowedTwice() failed after 0.009 seconds
with 1 issue.
> ✘ Test sameRelativeSymlinkFollowedTwice() recorded an issue at
TestEXT4Reader+IO.swift:516:6: Caught error: symlink loop while
resolving: ../target/../symlink/file.txt
> ✘ Test sameRelativeSymlinkFollowedTwice() failed after 0.010 seconds
with 1 issue.
Fixes the construction of the path and removed unnecessary code. Fixes
the added failing test:
> ✘ Test fileTreeNodePathWithAbsoluteRoot() recorded an issue at
TestEXT4Reader+IO.swift:600:9: Expectation failed: (dirPtr.pointee.path
→ /) == (FilePath("/dir") → /dir)
> ✘ Test fileTreeNodePathWithAbsoluteRoot() recorded an issue at
TestEXT4Reader+IO.swift:601:9: Expectation failed: (filePtr.pointee.path
→ /) == (FilePath("/dir/file") → /dir/file)
> ✘ Test fileTreeNodePathWithAbsoluteRoot() failed after 0.001 seconds
with 2 issues.
To be able to test vminitd/vmexec/linux specific packages on ci it'd be
a heck of a lot easier if `make` just worked. This should be the last
bit needed. The default goal currently compiles just fine after the
linux specific `make deps` is ran. Next in line would be adding decent
unit tests/actually getting ci setup for the linux bits.
Adds a guard against an empty range in the EXT4 formatter to prevent a
possible crash:
> Swift/arm64e-apple-macos.swiftinterface:6314: Fatal error: Range
requires lowerBound <= upperBound
Removes not used `FilePath.init?(Data)` which had a buffer overread. It
used `String(cString:)` which reads until `\0`, but `Data` is not
null-terminated.
I've added an optional progress handler for rootfs unpacking so that
consumers can show progress. The Ubuntu image takes about 8 seconds to
unpack on my machine, and I'm developing an app where it would be useful
to show progress in the UI.
Total size is determined in an optional first pass that scans archive
headers. Bytes written are then reported during unpacking. The optional
first pass adds 15 (Alpine) to 115 (Ubuntu) ms to unpacking duration on
my machine, depending on image size.
## What
Add a `DNS.validate()` method that verifies all nameserver entries are
valid IPv4 or IPv6 addresses. The method is called from
`Vminitd.configureDNS()` before applying the configuration.
## Why
Closes#467. Currently, any arbitrary string can be passed as a
nameserver in `DNSConfiguration`, which silently results in an invalid
`/etc/resolv.conf` inside the container. Hostname strings like
`dns.example.com` would be written to resolv.conf but would not work as
nameservers.
## How
- Added `DNS.validate() throws` method in `DNSConfiguration.swift` that
iterates over all nameservers and attempts to parse each as either an
`IPv4Address` or `IPv6Address` (using the existing parsers in
`ContainerizationExtras`)
- Added `import ContainerizationExtras` to `DNSConfiguration.swift` (the
`Containerization` target already depends on `ContainerizationExtras`)
- Called `config.validate()` at the start of `Vminitd.configureDNS()` so
validation happens before any GRPC call
## Testing
Added 6 new unit tests in `DNSTests.swift`:
- ✅ Valid IPv4 nameservers accepted
- ✅ Valid IPv6 nameservers accepted
- ✅ Mixed IPv4/IPv6 nameservers accepted
- ✅ Empty nameserver list accepted
- ❌ Hostname rejected
- ❌ Invalid address rejected
## Checklist
- [x] Tests added
- [x] No breaking changes to existing API (validate() is a new method,
existing init is unchanged)
- [x] Follows existing patterns (uses ContainerizationExtras IP address
types, ContainerizationError for errors)
Signed-off-by: Maxime Grenu <maxime.grenu@gmail.com>
- Fixes EXT4 timestamp encoding for pre-1970 dates
- Fixes EXT4 timestamp decoding for pre-1970 dates
- Fixes the creation date
- Fixes a `UInt32` overflow
Resolves the following failures in the added tests:
```
Swift/arm64e-apple-macos.swiftinterface:38198: Fatal error: Double value cannot be converted to UInt64 because the result would be less than UInt64.min
error: Process '/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/libexec/swift/pm/swiftpm-testing-helper --test-bundle-path /Users/Dmitry/Apple/containerization/.build/arm64-apple-macosx/debug/containerizationPackageTests.xctest/Contents/MacOS/containerizationPackageTests --filter encodeNegativeTimestamp /Users/Dmitry/Apple/containerization/.build/arm64-apple-macosx/debug/containerizationPackageTests.xctest/Contents/MacOS/containerizationPackageTests --testing-library swift-testing' exited with unexpected signal code 5
```
```
✘ Test decodeNegativeTimestamp() recorded an issue at TestEXT4Format+Create.swift:100:6: Caught error: not a valid EXT4 superblock
✘ Test decodeNegativeTimestamp() failed after 0.003 seconds with 1 issue.
✘ Suite NegativeTimestampRoundtripTests failed after 0.004 seconds with 1 issue.
✘ Test run with 1 test in 1 suite failed after 0.004 seconds with 1 issue.
```
The network protocol and VMNetNetwork implementation currently are
housed on ContainerManager even though they are generally useful types
even outside of this easy to use helper type. This change moves them to
not be nested types anymore, as well as exposes a new param on
VMNetNetworks constructor so we can pass the type of network.
Now that the static linux SDK we use has libarchive linked against it,
we can finally live our dream (/s) of supporting copying directories
in/out a little easier. This was.. kind of annoying. I think the very
simple route of writing archive to guest/host -> streaming over grpc is
simplest, but on the guest end we have a couple problems:
1. The VMs rootfs is read only today always, which is a good thing to me
and I don't want to change if we don't have to.
2. Writing the archive to the containers rootfs temporarily could work,
but it's a bit weird, and the user can make the containers rootfs
readonly which would screw that plan.
3. We could write it to /run or /tmp, but they're tmpfs and dealing with
the headache of the user possibly tarring an enormous dir is one I don't
want to care about.
So, that leaves us with the (truthfully better to me) approach of trying
to write the tar data directly to the host and skipping grpc which kinda
forces us to have a temp spot. Because of that, I made it such that we
pass a port number from host<->guest, and transfer the actual data
(either the single file or tarred dir contents) over the vsock port
instead. The stream is kinda clunky, but it just serves as a means to
exchange metadata and a "we're done" signifier.
This PR adds OCI Image Spec v1.1 artifact support. It extends Manifest,
Index, and Descriptor with the `subject` and `artifactType` fields, adds
a `referrers()` method to RegistryClient implementing the OCI
Distribution Spec v1.1 referrers API. Also, I've added some unit unit
tests for backward compatibility and roundtrip encpding of all new
fields
This PR adds a `networking: Bool = true` parameter to
`ContainerManager.create()` so callers can opt out of network interface
creation on a per-container basis.
## Motivation
Currently, `ContainerManager.create()` unconditionally allocates a vmnet
network interface for every container (when the manager has a network
configured). Some use cases don't need network access and benefit from
having it disabled to reduce attack surface.
There's no way to achieve this today without either:
- Initializing the `ContainerManager` without a network (which disables
networking for *all* containers)
- Clearing `config.interfaces` in the configuration closure (which
wastes an IP allocation from the vmnet pool since `network.create(id)`
has already been called)
## Changes
- Add `networking: Bool = true` to all three `create()` overloads on
`ContainerManager`
- When `false`, `self.network?.create(id)` is skipped entirely. No
interface is allocated, and no DNS is configured.
- `releaseNetwork`/`delete` remain safe to call regardless, since
`Allocator.release` silently ignores unknown IDs.
- Add unit test `testNetworkingFalseSkipsInterfaceCreation` using the
existing `NilGatewayNetwork` fixture
- Add integration tests `testNetworkingDisabled` and
`testNetworkingEnabled` that create containers through a network-enabled
`ContainerManager` and verify the presence/absence of `eth0` via
`/sys/class/net/`
## What
Raise the constant from 127 to 255 in `Reference.swift` and update the
derived `referenceTotalLengthMax` accordingly.
## Why
Closes#453.
The [OCI distribution
spec](https://github.com/opencontainers/distribution-spec/blob/main/spec.md)
states that the **name** component of an image reference (registry host
+ repository path) may be at most 255 bytes. The previous hard-coded
limit of 127 characters incorrectly rejected valid references that used
long registry hostnames or deep path hierarchies.
The old `referenceTotalLengthMax = 255` was also inconsistent: with a
127-char name cap, a 255-char total reference would only allow a very
short tag. The new value is derived explicitly as `nameTotalLengthMax
(255) + separator (1) + tagLengthMax (128) = 384`.
## How
- `nameTotalLengthMax`: 127 → 255
- `tagLengthMax`: new constant (128) documenting the maximum tag length
already enforced by the tag regex (`{0,127}` + leading char = 128
chars).
- `referenceTotalLengthMax`: computed from the two constants above (384)
rather than hard-coded to 255.
## Testing
Added three new cases in `ReferenceTests.swift`:
- ✅ Name of 128 characters (registry + path) — previously rejected, now
accepted
- ✅ Name of exactly 255 characters — at the OCI spec maximum, accepted
- ❌ Name of 256 characters — one over the limit, rejected
- Guarded against ipv4Gateway if nil and throw
`ContainerizationError(.invalidState, ...)` instead of force unwraping
- Added a unit test
`ContainerManagerTests.testCreateThrowsWhenGatewayMissing`
Islam Gagiev