Also fixing a "defer in loop" warning, instead changing to use
sub-tests, and simplifying some code, using os.WriteFile() instead.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
The existing pkg/archive unit tests are primarily round-trip tests which
assert that pkg/archive produces tarballs which pkg/archive can unpack.
While these tests are effective at catching regressions in archiving or
unarchiving, they have a blind spot for regressions in compatibility
with the rest of the ecosystem. For example, a typo in the capabilities
extended attribute constant would result in subtly broken image layer
tarballs, but the existing tests would not catch the bug if both the
archiving and unarchiving implementations have the same typo.
Extend the test for archiving an overlay filesystem layer to assert that
the overlayfs style whiteouts (extended attributes and device files) are
transformed into AUFS-style whiteouts (magic file names).
Extend the test for archiving files with extended attributes to assert
that the extended attribute is encoded into the file's tar header in the
standard, interoperable format compatible with the rest of the
ecosystem.
Signed-off-by: Cory Snider <csnider@mirantis.com>
The github.com/containerd/containerd/log package was moved to a separate
module, which will also be used by upcoming (patch) releases of containerd.
This patch moves our own uses of the package to use the new module.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Extended attributes are set on files in container images for a reason.
Fail to unpack if extended attributes are present in a layer and setting
the attributes on the unpacked files fails for any reason.
Add an option to the vfs graph driver to opt into the old behaviour
where ENOTSUPP and EPERM errors encountered when setting extended
attributes are ignored. Make it abundantly clear to users and anyone
triaging their bug reports that they are shooting themselves in the
foot by enabling this option.
Signed-off-by: Cory Snider <csnider@mirantis.com>
"math/rand".Seed
- Migrate to using local RNG instances.
"archive/tar".TypeRegA
- The deprecated constant tar.TypeRegA is the same value as
tar.TypeReg and so is not needed at all.
Signed-off-by: Cory Snider <csnider@mirantis.com>
This one is a "bit" fuzzy, as it may not be _directly_ related to `archive`,
but it's always used _in combination_ with the archive package, so moving it
there.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This is a partial revert of 7ca0cb7ffa, which
switched from os/exec to the golang.org/x/sys/execabs package to mitigate
security issues (mainly on Windows) with lookups resolving to binaries in the
current directory.
from the go1.19 release notes https://go.dev/doc/go1.19#os-exec-path
> ## PATH lookups
>
> Command and LookPath no longer allow results from a PATH search to be found
> relative to the current directory. This removes a common source of security
> problems but may also break existing programs that depend on using, say,
> exec.Command("prog") to run a binary named prog (or, on Windows, prog.exe) in
> the current directory. See the os/exec package documentation for information
> about how best to update such programs.
>
> On Windows, Command and LookPath now respect the NoDefaultCurrentDirectoryInExePath
> environment variable, making it possible to disable the default implicit search
> of “.” in PATH lookups on Windows systems.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Unshare the thread's file system attributes and, if applicable, mount
namespace so that the chroot operation does not affect the rest of the
process.
Signed-off-by: Cory Snider <csnider@mirantis.com>
The applyLayer implementation in pkg/chrootarchive has to set the TMPDIR
environment variable so that archive.UnpackLayer() can successfully
create the whiteout-file temp directory. Change UnpackLayer to create
the temporary directory under the destination path so that environment
variables do not need to be touched.
Signed-off-by: Cory Snider <csnider@mirantis.com>
It was only used in a couple of places, and in most places shouldn't be used
as those locations were in unix/linux-only files, so didn't need the wrapper.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
pkg/directory/directory.go:9:49: empty-lines: extra empty line at the start of a block (revive)
pkg/pubsub/publisher.go:8:48: empty-lines: extra empty line at the start of a block (revive)
pkg/loopback/attach_loopback.go:96:69: empty-lines: extra empty line at the start of a block (revive)
pkg/devicemapper/devmapper_wrapper.go:136:48: empty-lines: extra empty line at the start of a block (revive)
pkg/devicemapper/devmapper.go:391:35: empty-lines: extra empty line at the end of a block (revive)
pkg/devicemapper/devmapper.go:676:35: empty-lines: extra empty line at the end of a block (revive)
pkg/archive/changes_posix_test.go:15:38: empty-lines: extra empty line at the end of a block (revive)
pkg/devicemapper/devmapper.go:241:51: empty-lines: extra empty line at the start of a block (revive)
pkg/fileutils/fileutils_test.go:17:47: empty-lines: extra empty line at the end of a block (revive)
pkg/fileutils/fileutils_test.go:34:48: empty-lines: extra empty line at the end of a block (revive)
pkg/fileutils/fileutils_test.go:318:32: empty-lines: extra empty line at the end of a block (revive)
pkg/tailfile/tailfile.go:171:6: empty-lines: extra empty line at the end of a block (revive)
pkg/tarsum/fileinfosums_test.go:16:41: empty-lines: extra empty line at the end of a block (revive)
pkg/tarsum/tarsum_test.go:198:42: empty-lines: extra empty line at the start of a block (revive)
pkg/tarsum/tarsum_test.go:294:25: empty-lines: extra empty line at the start of a block (revive)
pkg/tarsum/tarsum_test.go:407:34: empty-lines: extra empty line at the end of a block (revive)
pkg/ioutils/fswriters_test.go:52:45: empty-lines: extra empty line at the end of a block (revive)
pkg/ioutils/writers_test.go:24:39: empty-lines: extra empty line at the end of a block (revive)
pkg/ioutils/bytespipe_test.go:78:26: empty-lines: extra empty line at the end of a block (revive)
pkg/sysinfo/sysinfo_linux_test.go:13:37: empty-lines: extra empty line at the end of a block (revive)
pkg/archive/archive_linux_test.go:57:64: empty-lines: extra empty line at the end of a block (revive)
pkg/archive/changes.go:248:72: empty-lines: extra empty line at the start of a block (revive)
pkg/archive/changes_posix_test.go:15:38: empty-lines: extra empty line at the end of a block (revive)
pkg/archive/copy.go:248:124: empty-lines: extra empty line at the end of a block (revive)
pkg/archive/diff_test.go:198:44: empty-lines: extra empty line at the end of a block (revive)
pkg/archive/archive.go:304:12: empty-lines: extra empty line at the end of a block (revive)
pkg/archive/archive.go:749:37: empty-lines: extra empty line at the end of a block (revive)
pkg/archive/archive.go:812:81: empty-lines: extra empty line at the start of a block (revive)
pkg/archive/copy_unix_test.go:347:34: empty-lines: extra empty line at the end of a block (revive)
pkg/system/path.go:11:39: empty-lines: extra empty line at the end of a block (revive)
pkg/system/meminfo_linux.go:29:21: empty-lines: extra empty line at the end of a block (revive)
pkg/plugins/plugins.go:135:32: empty-lines: extra empty line at the end of a block (revive)
pkg/authorization/response.go:71:48: empty-lines: extra empty line at the start of a block (revive)
pkg/authorization/api_test.go:18:51: empty-lines: extra empty line at the end of a block (revive)
pkg/authorization/middleware_test.go:23:44: empty-lines: extra empty line at the end of a block (revive)
pkg/authorization/middleware_unix_test.go:17:46: empty-lines: extra empty line at the end of a block (revive)
pkg/authorization/api_test.go:57:45: empty-lines: extra empty line at the end of a block (revive)
pkg/authorization/response.go:83:50: empty-lines: extra empty line at the start of a block (revive)
pkg/authorization/api_test.go:66:47: empty-lines: extra empty line at the end of a block (revive)
pkg/authorization/middleware_unix_test.go:45:48: empty-lines: extra empty line at the end of a block (revive)
pkg/authorization/response.go:145:75: empty-lines: extra empty line at the start of a block (revive)
pkg/authorization/middleware_unix_test.go:56:51: empty-lines: extra empty line at the end of a block (revive)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This code was duplicated in two places -- factor it out, add
documentation, and move magic numbers into a constant.
Additionally, use the same permissions (0755) in both code paths, and
ensure that the ID map is used in both code paths.
Co-authored-by: Vasiliy Ulyanov <vulyanov@suse.de>
Signed-off-by: Bjorn Neergaard <bneergaard@mirantis.com>
Signed-off-by: Vasiliy Ulyanov <vulyanov@suse.de>
1. Commit 1a22418f9f changed permissions to `0700`
on Windows, or more factually, it removed `rw` (`chmod g-rw,o-rw`) and added
executable bits (`chmod u+x`).
2. This was too restrictive, and b7dc9040f0 changed
permissions to only remove the group- and world-writable bits to give read and
execute access to everyone, but setting execute permissions for everyone.
3. However, this also removed the non-permission bits, so 41eb61d5c2
updated the code to preserve those, and keep parity with Linux.
This changes it back to `2.`. I wonder (_think_) _permission_ bits (read, write)
can be portable, except for the _executable_ bit (which is not present on Windows).
The alternative could be to keep the permission bits, and only set the executable
bit (`perm | 0111`) for everyone (equivalent of `chmod +x`), but that likely would
be a breaking change.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
The fillGo18FileTypeBits func was added in 1a451d9a7b
to keep the tar headers consistent with headers created with go1.8 and older.
go1.8 and older incorrectly preserved all file-mode bits, including file-type,
instead of stripping those bits and only preserving the _permission_ bits, as
defined in;
- the GNU tar spec: https://www.gnu.org/software/tar/manual/html_node/Standard.html
- and POSIX: http://pubs.opengroup.org/onlinepubs/009695399/basedefs/tar.h.html
We decided at the time to copy the "wrong" behavior to prevent a cache-bust and
to keep the archives identical, however:
- It's not matching the standards, which causes differences between our tar
implementation and the standard tar implementations, as well as implementations
in other languages, such as Python (see docker/compose#883).
- BuildKit does not implement this hack.
- We don't _need_ this extra information (as it's already preserved in the
type header; https://pkg.go.dev/archive/tar#pkg-constants
In short; let's remove this hack.
This reverts commit 1a451d9a7b.
This reverts commit 41eb61d5c2.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Now that CanonicalTarNameForPath is an alias for filepath.ToSlash, they were
mostly redundant, and only testing Go's stdlib. Coverage for filepath.ToSlash is
provided through TestCanonicalTarName, which does a superset of CanonicalTarNameForPath,
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
filepath.ToSlash is already a no-op on non-Windows platforms, so there's no
need to provide multiple implementations.
We could consider deprecating this function, but it's used in the CLI, and
perhaps it's still useful to have a canonical location to perform this normalization.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Migrating these functions to allow them being shared between moby, docker/cli,
and containerd, and to allow using them without importing all of sys / system,
which (in containerd) also depends on hcsshim and more.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Older versions of Go don't format comments, so committing this as
a separate commit, so that we can already make these changes before
we upgrade to Go 1.19.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
strings.ReplaceAll(s, old, new) is a wrapper function for
strings.Replace(s, old, new, -1). But strings.ReplaceAll is more
readable and removes the hardcoded -1.
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
This commit replaces `os.Setenv` with `t.Setenv` in tests. The
environment variable is automatically restored to its original value
when the test and all its subtests complete.
Reference: https://pkg.go.dev/testing#T.Setenv
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
Finish the refactor which was partially completed with commit
34536c498d, passing around IdentityMapping structs instead of pairs of
[]IDMap slices.
Existing code which uses []IDMap relies on zero-valued fields to be
valid, empty mappings. So in order to successfully finish the
refactoring without introducing bugs, their replacement therefore also
needs to have a useful zero value which represents an empty mapping.
Change IdentityMapping to be a pass-by-value type so that there are no
nil pointers to worry about.
The functionality provided by the deprecated NewIDMappingsFromMaps
function is required by unit tests to to construct arbitrary
IdentityMapping values. And the daemon will always need to access the
mappings to pass them to the Linux kernel. Accommodate these use cases
by exporting the struct fields instead. BuildKit currently depends on
the UIDs and GIDs methods so we cannot get rid of them yet.
Signed-off-by: Cory Snider <csnider@mirantis.com>
The recently-upgraded gosec linter has a rule for archive extraction
code which may be vulnerable to directory traversal attacks, a.k.a. Zip
Slip. Gosec's detection is unfortunately prone to false positives,
however: it flags any filepath.Join call with an argument derived from a
tar.Header value, irrespective of whether the resultant path is used for
filesystem operations or if directory traversal attacks are guarded
against.
All of the lint errors reported by gosec appear to be false positives.
Signed-off-by: Cory Snider <csnider@mirantis.com>
A copy of Go's archive/tar packge was vendored with a patch applied to
mitigate CVE-2019-14271. Vendoring standard library packages is not
supported by Go in module-aware mode, which is getting in the way of
maintenance. A different approach to mitigate the vulnerability is
needed which does not involve vendoring parts of the standard library.
glibc implements name service lookups such as users, groups and DNS
using a scheme known as Name Service Switch. The services are
implemented as modules, shared libraries which glibc dynamically links
into the process the first time a function requiring the module is
called. This is the crux of the vulnerability: if a process linked
against glibc chroots, then calls one of the functions implemented with
NSS for the first time, glibc may load NSS modules out of the chrooted
filesystem.
The API underlying the `docker cp` command is implemented by forking a
new process which chroots into the container's rootfs and writes a tar
stream of files from the container over standard output. It utilizes the
Go standard library's archive/tar package to write the tar stream. It
makes use of the tar.FileInfoHeader function to construct a tar.Header
value from an fs.FileInfo value. In modern versions of Go on *nix
platforms, FileInfoHeader will attempt to resolve the file's UID and GID
to their respective user and group names by calling the os/user
functions LookupId and LookupGroupId. The cgo implementation of os/user
on *nix performs lookups by calling the corresponding libc functions. So
when linked against glibc, calls to tar.FileInfoHeader after the
process has chrooted into the container's rootfs can have the side
effect of loading NSS modules from the container! Without any
mitigations, a malicious container image author can trivially get
arbitrary code execution by leveraging this vulnerability and escape the
chroot (which is not a sandbox) into the host.
Mitigate the vulnerability without patching or forking archive/tar by
hiding the OS-dependent file info from tar.FileInfoHeader which it needs
to perform the lookups. Without that information available it falls back
to populating the tar.Header with only the information obtainable
directly from the FileInfo value without making any calls into os/user.
Fixes#42402
Signed-off-by: Cory Snider <csnider@mirantis.com>
The existing code does not correctly handle the case where a file
matches one of the patterns, but should not match overall because of an
exclude pattern that applied to a parent directory (see
https://github.com/docker/buildx/issues/850).
Fix this by independently tracking the results of matching against each
pattern. A file should be considered to match any pattern that matched a
parent dir.
Signed-off-by: Aaron Lehmann <alehmann@netflix.com>
As a matter of fact, there are two frame formats defined by Zstandard: Zstandard frames and Skippable frames.
So we should probably support zstd algorithms with skippable frames.
See https://tools.ietf.org/id/draft-kucherawy-dispatch-zstd-00.html#rfc.section.2 for more details.
Signed-off-by: Da McGrady <dabkb@aol.com>
zstd is a compression algorithm that has a very fast decoder, while
providing also good compression ratios. The fast decoder makes it
suitable for container images, as decompressing the tarballs is a very
expensive operation.
https://github.com/opencontainers/image-spec/pull/788 added support
for zstd to the OCI image specs.
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
The io/ioutil package has been deprecated in Go 1.16. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
