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.
- Closesapple/container#988.
- macOS libarchive is not built with zstd support, so the workaround in
ArchiveReader is to attempt to decompress every archive as zstd. If
decompression fails, we pass the original archive to libarchive. If it
succeeds, we pass the uncompressed archive.
- Adds blob media type recognition for zstd to EXT4Unpacker. Tested zstd
blob unpack using `image pull tonistiigi/hello-world:zstd-docker`.
Co-authored-by: Aditya Ramani <a_ramani@apple.com>
* Admit only valid OCI layout files when loading image.
- Adds `AdmissionMapper` protocol for validating archive
member paths and normalizing them to relative paths
under the extraction root directory.
- Renames `Reader.swift` to `ArchiveReader.swift` to
match type name.
- Rework `TempDir` to address `NSString.utf8String`
deprecation warning in Swift 6.2.3.
- Rework `ArchiveReader.extractContent()` to use an
`AdmissionMapper` to validate and remap archive
members before extracting.
- Adds `IdentityAdmissionWrapper` for naive extraction.
- Adds `NoSymlinkAdmissionWrapper` that only extracts
regular files and directories under the extraction root.
- Adds `OCIImageAdmissionWrapper` that only extracts
valid OCI image layout paths.
- Use `OCIImageAdmissionWrapper` for `cctl image load`
and print rejected paths.
* PR feedback.
* Adds public init() for TrustedAdmissionMapper.
* Replace AdmissionMapper with more secure extraction.
- Adds FileDescriptor.mkdirSecure() to prevent
root escapes on member pathnames, and to prevent
symlink traversal.
- Adds FileDescriptor.unlinkRecursive() to
facilitate overwrites when there are multiple
archive entries with the same member path.
- Adds FileDescriptor.validateSymlinkTargetInRoot()
to validate that extracted symlink targets do
not escape the root.
- Rewrite ArchiveReader.extractContents() to use
secure path functions.
* Remove unneeded symlink check, rename files.
* Simplify the lexical normalizer workaround.
* Reject member paths containing parent traversal components.
* Remove unused lexical normalization workaround.
* Fix leaking fds, extract absolute members as relative.
Danny Canter