func renderSumForHeader(v Version, h *tar.Header, data []byte) (string, error) {
buf := bytes.NewBuffer(nil)
// first build our test tar
tw := tar.NewWriter(buf)
if err := tw.WriteHeader(h); err != nil {
return "", err
}
if _, err := tw.Write(data); err != nil {
return "", err
}
tw.Close()
ts, err := NewTarSum(buf, true, v)
if err != nil {
return "", err
}
tr := tar.NewReader(ts)
for {
hdr, err := tr.Next()
if hdr == nil || err == io.EOF {
// Signals the end of the archive.
break
}
if err != nil {
return "", err
}
if _, err = io.Copy(ioutil.Discard, tr); err != nil {
return "", err
}
}
return ts.Sum(nil), nil
}
func (archiver *Archiver) CopyFileWithTar(src, dst string) (err error) {
log.Debugf("CopyFileWithTar(%s, %s)", src, dst)
srcSt, err := os.Stat(src)
if err != nil {
return err
}
if srcSt.IsDir() {
return fmt.Errorf("Can't copy a directory")
}
// Clean up the trailing /
if dst[len(dst)-1] == '/' {
dst = path.Join(dst, filepath.Base(src))
}
// Create the holding directory if necessary
if err := os.MkdirAll(filepath.Dir(dst), 0700); err != nil && !os.IsExist(err) {
return err
}
r, w := io.Pipe()
errC := promise.Go(func() error {
defer w.Close()
srcF, err := os.Open(src)
if err != nil {
return err
}
defer srcF.Close()
hdr, err := tar.FileInfoHeader(srcSt, "")
if err != nil {
return err
}
hdr.Name = filepath.Base(dst)
hdr.Mode = int64(chmodTarEntry(os.FileMode(hdr.Mode)))
tw := tar.NewWriter(w)
defer tw.Close()
if err := tw.WriteHeader(hdr); err != nil {
return err
}
if _, err := io.Copy(tw, srcF); err != nil {
return err
}
return nil
})
defer func() {
if er := <-errC; err != nil {
err = er
}
}()
return archiver.Untar(r, filepath.Dir(dst), nil)
}
func emptyTarSum(gzip bool) (TarSum, error) {
reader, writer := io.Pipe()
tarWriter := tar.NewWriter(writer)
// Immediately close tarWriter and write-end of the
// Pipe in a separate goroutine so we don't block.
go func() {
tarWriter.Close()
writer.Close()
}()
return NewTarSum(reader, !gzip, Version0)
}
// ExportChanges produces an Archive from the provided changes, relative to dir.
func ExportChanges(dir string, changes []Change) (Archive, error) {
reader, writer := io.Pipe()
go func() {
ta := &tarAppender{
TarWriter: tar.NewWriter(writer),
Buffer: pools.BufioWriter32KPool.Get(nil),
SeenFiles: make(map[uint64]string),
}
// this buffer is needed for the duration of this piped stream
defer pools.BufioWriter32KPool.Put(ta.Buffer)
sort.Sort(changesByPath(changes))
// In general we log errors here but ignore them because
// during e.g. a diff operation the container can continue
// mutating the filesystem and we can see transient errors
// from this
for _, change := range changes {
if change.Kind == ChangeDelete {
whiteOutDir := filepath.Dir(change.Path)
whiteOutBase := filepath.Base(change.Path)
whiteOut := filepath.Join(whiteOutDir, ".wh."+whiteOutBase)
timestamp := time.Now()
hdr := &tar.Header{
Name: whiteOut[1:],
Size: 0,
ModTime: timestamp,
AccessTime: timestamp,
ChangeTime: timestamp,
}
if err := ta.TarWriter.WriteHeader(hdr); err != nil {
log.Debugf("Can't write whiteout header: %s", err)
}
} else {
path := filepath.Join(dir, change.Path)
if err := ta.addTarFile(path, change.Path[1:]); err != nil {
log.Debugf("Can't add file %s to tar: %s", path, err)
}
}
}
// Make sure to check the error on Close.
if err := ta.TarWriter.Close(); err != nil {
log.Debugf("Can't close layer: %s", err)
}
if err := writer.Close(); err != nil {
log.Debugf("failed close Changes writer: %s", err)
}
}()
return reader, nil
}
// make a tar:
// * num is the number of files the tar should have
// * size is the bytes per file
// * isRand is whether the contents of the files should be a random chunk (otherwise it's all zeros)
// * realFile will write to a TempFile, instead of an in memory buffer
func sizedTar(opts sizedOptions) io.Reader {
var (
fh io.ReadWriter
err error
)
if opts.realFile {
fh, err = ioutil.TempFile("", "tarsum")
if err != nil {
return nil
}
} else {
fh = bytes.NewBuffer([]byte{})
}
tarW := tar.NewWriter(fh)
defer tarW.Close()
for i := int64(0); i < opts.num; i++ {
err := tarW.WriteHeader(&tar.Header{
Name: fmt.Sprintf("/testdata%d", i),
Mode: 0755,
Uid: 0,
Gid: 0,
Size: opts.size,
})
if err != nil {
return nil
}
var rBuf []byte
if opts.isRand {
rBuf = make([]byte, 8)
_, err = rand.Read(rBuf)
if err != nil {
return nil
}
} else {
rBuf = []byte{0, 0, 0, 0, 0, 0, 0, 0}
}
for i := int64(0); i < opts.size/int64(8); i++ {
tarW.Write(rBuf)
}
}
return fh
}
func (ts *tarSum) initTarSum() error {
ts.bufTar = bytes.NewBuffer([]byte{})
ts.bufWriter = bytes.NewBuffer([]byte{})
ts.tarR = tar.NewReader(ts.Reader)
ts.tarW = tar.NewWriter(ts.bufTar)
if !ts.DisableCompression {
ts.writer = gzip.NewWriter(ts.bufWriter)
} else {
ts.writer = &nopCloseFlusher{Writer: ts.bufWriter}
}
if ts.tHash == nil {
ts.tHash = DefaultTHash
}
ts.h = ts.tHash.Hash()
ts.h.Reset()
ts.first = true
ts.sums = FileInfoSums{}
return nil
}
func ExportChanges(dir string, changes []Change) (Archive, error) {
reader, writer := io.Pipe()
tw := tar.NewWriter(writer)
go func() {
twBuf := bufio.NewWriterSize(nil, twBufSize)
// In general we log errors here but ignore them because
// during e.g. a diff operation the container can continue
// mutating the filesystem and we can see transient errors
// from this
for _, change := range changes {
if change.Kind == ChangeDelete {
whiteOutDir := filepath.Dir(change.Path)
whiteOutBase := filepath.Base(change.Path)
whiteOut := filepath.Join(whiteOutDir, ".wh."+whiteOutBase)
timestamp := time.Now()
hdr := &tar.Header{
Name: whiteOut[1:],
Size: 0,
ModTime: timestamp,
AccessTime: timestamp,
ChangeTime: timestamp,
}
if err := tw.WriteHeader(hdr); err != nil {
utils.Debugf("Can't write whiteout header: %s\n", err)
}
} else {
path := filepath.Join(dir, change.Path)
if err := addTarFile(path, change.Path[1:], tw, twBuf); err != nil {
utils.Debugf("Can't add file %s to tar: %s\n", path, err)
}
}
}
// Make sure to check the error on Close.
if err := tw.Close(); err != nil {
utils.Debugf("Can't close layer: %s\n", err)
}
writer.Close()
}()
return reader, nil
}
// Generate generates a new archive from the content provided
// as input.
//
// `files` is a sequence of path/content pairs. A new file is
// added to the archive for each pair.
// If the last pair is incomplete, the file is created with an
// empty content. For example:
//
// Generate("foo.txt", "hello world", "emptyfile")
//
// The above call will return an archive with 2 files:
// * ./foo.txt with content "hello world"
// * ./empty with empty content
//
// FIXME: stream content instead of buffering
// FIXME: specify permissions and other archive metadata
func Generate(input ...string) (Archive, error) {
files := parseStringPairs(input...)
buf := new(bytes.Buffer)
tw := tar.NewWriter(buf)
for _, file := range files {
name, content := file[0], file[1]
hdr := &tar.Header{
Name: name,
Size: int64(len(content)),
}
if err := tw.WriteHeader(hdr); err != nil {
return nil, err
}
if _, err := tw.Write([]byte(content)); err != nil {
return nil, err
}
}
if err := tw.Close(); err != nil {
return nil, err
}
return ioutil.NopCloser(buf), nil
}
func fakeTar() (io.Reader, error) {
uid := os.Getuid()
gid := os.Getgid()
content := []byte("Hello world!\n")
buf := new(bytes.Buffer)
tw := tar.NewWriter(buf)
for _, name := range []string{"/etc/postgres/postgres.conf", "/etc/passwd", "/var/log/postgres/postgres.conf"} {
hdr := new(tar.Header)
// Leaving these fields blank requires root privileges
hdr.Uid = uid
hdr.Gid = gid
hdr.Size = int64(len(content))
hdr.Name = name
if err := tw.WriteHeader(hdr); err != nil {
return nil, err
}
tw.Write([]byte(content))
}
tw.Close()
return buf, nil
}
// TarWithOptions creates an archive from the directory at `path`, only including files whose relative
// paths are included in `options.Includes` (if non-nil) or not in `options.Excludes`.
func TarWithOptions(srcPath string, options *TarOptions) (io.ReadCloser, error) {
pipeReader, pipeWriter := io.Pipe()
compressWriter, err := CompressStream(pipeWriter, options.Compression)
if err != nil {
return nil, err
}
tw := tar.NewWriter(compressWriter)
go func() {
// In general we log errors here but ignore them because
// during e.g. a diff operation the container can continue
// mutating the filesystem and we can see transient errors
// from this
if options.Includes == nil {
options.Includes = []string{"."}
}
twBuf := bufio.NewWriterSize(nil, twBufSize)
for _, include := range options.Includes {
filepath.Walk(filepath.Join(srcPath, include), func(filePath string, f os.FileInfo, err error) error {
if err != nil {
utils.Debugf("Tar: Can't stat file %s to tar: %s\n", srcPath, err)
return nil
}
relFilePath, err := filepath.Rel(srcPath, filePath)
if err != nil {
return nil
}
for _, exclude := range options.Excludes {
matched, err := filepath.Match(exclude, relFilePath)
if err != nil {
utils.Errorf("Error matching: %s (pattern: %s)", relFilePath, exclude)
return err
}
if matched {
if filepath.Clean(relFilePath) == "." {
utils.Errorf("Can't exclude whole path, excluding pattern: %s", exclude)
continue
}
utils.Debugf("Skipping excluded path: %s", relFilePath)
if f.IsDir() {
return filepath.SkipDir
}
return nil
}
}
if err := addTarFile(filePath, relFilePath, tw, twBuf); err != nil {
utils.Debugf("Can't add file %s to tar: %s\n", srcPath, err)
}
return nil
})
}
// Make sure to check the error on Close.
if err := tw.Close(); err != nil {
utils.Debugf("Can't close tar writer: %s\n", err)
}
if err := compressWriter.Close(); err != nil {
utils.Debugf("Can't close compress writer: %s\n", err)
}
if err := pipeWriter.Close(); err != nil {
utils.Debugf("Can't close pipe writer: %s\n", err)
}
}()
return pipeReader, nil
}
// TarWithOptions creates an archive from the directory at `path`, only including files whose relative
// paths are included in `options.IncludeFiles` (if non-nil) or not in `options.ExcludePatterns`.
func TarWithOptions(srcPath string, options *TarOptions) (io.ReadCloser, error) {
pipeReader, pipeWriter := io.Pipe()
compressWriter, err := CompressStream(pipeWriter, options.Compression)
if err != nil {
return nil, err
}
go func() {
ta := &tarAppender{
TarWriter: tar.NewWriter(compressWriter),
Buffer: pools.BufioWriter32KPool.Get(nil),
SeenFiles: make(map[uint64]string),
}
// this buffer is needed for the duration of this piped stream
defer pools.BufioWriter32KPool.Put(ta.Buffer)
// In general we log errors here but ignore them because
// during e.g. a diff operation the container can continue
// mutating the filesystem and we can see transient errors
// from this
if options.IncludeFiles == nil {
options.IncludeFiles = []string{"."}
}
seen := make(map[string]bool)
var renamedRelFilePath string // For when tar.Options.Name is set
for _, include := range options.IncludeFiles {
filepath.Walk(filepath.Join(srcPath, include), func(filePath string, f os.FileInfo, err error) error {
if err != nil {
log.Debugf("Tar: Can't stat file %s to tar: %s", srcPath, err)
return nil
}
relFilePath, err := filepath.Rel(srcPath, filePath)
if err != nil || (relFilePath == "." && f.IsDir()) {
// Error getting relative path OR we are looking
// at the root path. Skip in both situations.
return nil
}
skip := false
// If "include" is an exact match for the current file
// then even if there's an "excludePatterns" pattern that
// matches it, don't skip it. IOW, assume an explicit 'include'
// is asking for that file no matter what - which is true
// for some files, like .dockerignore and Dockerfile (sometimes)
if include != relFilePath {
skip, err = fileutils.Matches(relFilePath, options.ExcludePatterns)
if err != nil {
log.Debugf("Error matching %s", relFilePath, err)
return err
}
}
if skip {
if f.IsDir() {
return filepath.SkipDir
}
return nil
}
if seen[relFilePath] {
return nil
}
seen[relFilePath] = true
// Rename the base resource
if options.Name != "" && filePath == srcPath+"/"+filepath.Base(relFilePath) {
renamedRelFilePath = relFilePath
}
// Set this to make sure the items underneath also get renamed
if options.Name != "" {
relFilePath = strings.Replace(relFilePath, renamedRelFilePath, options.Name, 1)
}
if err := ta.addTarFile(filePath, relFilePath); err != nil {
log.Debugf("Can't add file %s to tar: %s", filePath, err)
}
return nil
})
}
// Make sure to check the error on Close.
if err := ta.TarWriter.Close(); err != nil {
log.Debugf("Can't close tar writer: %s", err)
}
if err := compressWriter.Close(); err != nil {
log.Debugf("Can't close compress writer: %s", err)
}
if err := pipeWriter.Close(); err != nil {
log.Debugf("Can't close pipe writer: %s", err)
}
}()
return pipeReader, nil
}
// testBreakout is a helper function that, within the provided `tmpdir` directory,
// creates a `victim` folder with a generated `hello` file in it.
// `untar` extracts to a directory named `dest`, the tar file created from `headers`.
//
// Here are the tested scenarios:
// - removed `victim` folder (write)
// - removed files from `victim` folder (write)
// - new files in `victim` folder (write)
// - modified files in `victim` folder (write)
// - file in `dest` with same content as `victim/hello` (read)
//
// When using testBreakout make sure you cover one of the scenarios listed above.
func testBreakout(untarFn string, tmpdir string, headers []*tar.Header) error {
tmpdir, err := ioutil.TempDir("", tmpdir)
if err != nil {
return err
}
defer os.RemoveAll(tmpdir)
dest := filepath.Join(tmpdir, "dest")
if err := os.Mkdir(dest, 0755); err != nil {
return err
}
victim := filepath.Join(tmpdir, "victim")
if err := os.Mkdir(victim, 0755); err != nil {
return err
}
hello := filepath.Join(victim, "hello")
helloData, err := time.Now().MarshalText()
if err != nil {
return err
}
if err := ioutil.WriteFile(hello, helloData, 0644); err != nil {
return err
}
helloStat, err := os.Stat(hello)
if err != nil {
return err
}
reader, writer := io.Pipe()
go func() {
t := tar.NewWriter(writer)
for _, hdr := range headers {
t.WriteHeader(hdr)
}
t.Close()
}()
untar := testUntarFns[untarFn]
if untar == nil {
return fmt.Errorf("could not find untar function %q in testUntarFns", untarFn)
}
if err := untar(dest, reader); err != nil {
if _, ok := err.(breakoutError); !ok {
// If untar returns an error unrelated to an archive breakout,
// then consider this an unexpected error and abort.
return err
}
// Here, untar detected the breakout.
// Let's move on verifying that indeed there was no breakout.
fmt.Printf("breakoutError: %v\n", err)
}
// Check victim folder
f, err := os.Open(victim)
if err != nil {
// codepath taken if victim folder was removed
return fmt.Errorf("archive breakout: error reading %q: %v", victim, err)
}
defer f.Close()
// Check contents of victim folder
//
// We are only interested in getting 2 files from the victim folder, because if all is well
// we expect only one result, the `hello` file. If there is a second result, it cannot
// hold the same name `hello` and we assume that a new file got created in the victim folder.
// That is enough to detect an archive breakout.
names, err := f.Readdirnames(2)
if err != nil {
// codepath taken if victim is not a folder
return fmt.Errorf("archive breakout: error reading directory content of %q: %v", victim, err)
}
for _, name := range names {
if name != "hello" {
// codepath taken if new file was created in victim folder
return fmt.Errorf("archive breakout: new file %q", name)
}
}
// Check victim/hello
f, err = os.Open(hello)
if err != nil {
// codepath taken if read permissions were removed
return fmt.Errorf("archive breakout: could not lstat %q: %v", hello, err)
}
defer f.Close()
b, err := ioutil.ReadAll(f)
if err != nil {
return err
}
fi, err := f.Stat()
if err != nil {
return err
}
if helloStat.IsDir() != fi.IsDir() ||
// TODO: cannot check for fi.ModTime() change
helloStat.Mode() != fi.Mode() ||
helloStat.Size() != fi.Size() ||
!bytes.Equal(helloData, b) {
// codepath taken if hello has been modified
return fmt.Errorf("archive breakout: file %q has been modified. Contents: expected=%q, got=%q. FileInfo: expected=%#v, got=%#v.", hello, helloData, b, helloStat, fi)
}
// Check that nothing in dest/ has the same content as victim/hello.
// Since victim/hello was generated with time.Now(), it is safe to assume
// that any file whose content matches exactly victim/hello, managed somehow
// to access victim/hello.
return filepath.Walk(dest, func(path string, info os.FileInfo, err error) error {
if info.IsDir() {
if err != nil {
// skip directory if error
return filepath.SkipDir
}
// enter directory
return nil
}
if err != nil {
// skip file if error
return nil
}
b, err := ioutil.ReadFile(path)
if err != nil {
// Houston, we have a problem. Aborting (space)walk.
return err
}
if bytes.Equal(helloData, b) {
return fmt.Errorf("archive breakout: file %q has been accessed via %q", hello, path)
}
return nil
})
}
func (ts *TarSum) Read(buf []byte) (int, error) {
if ts.gz == nil {
ts.bufTar = bytes.NewBuffer([]byte{})
ts.bufGz = bytes.NewBuffer([]byte{})
ts.tarR = tar.NewReader(ts.Reader)
ts.tarW = tar.NewWriter(ts.bufTar)
if !ts.DisableCompression {
ts.gz = gzip.NewWriter(ts.bufGz)
} else {
ts.gz = &nopCloseFlusher{Writer: ts.bufGz}
}
ts.h = sha256.New()
ts.h.Reset()
ts.first = true
ts.sums = make(map[string]string)
}
if ts.finished {
return ts.bufGz.Read(buf)
}
buf2 := make([]byte, len(buf), cap(buf))
n, err := ts.tarR.Read(buf2)
if err != nil {
if err == io.EOF {
if _, err := ts.h.Write(buf2[:n]); err != nil {
return 0, err
}
if !ts.first {
ts.sums[ts.currentFile] = hex.EncodeToString(ts.h.Sum(nil))
ts.h.Reset()
} else {
ts.first = false
}
currentHeader, err := ts.tarR.Next()
if err != nil {
if err == io.EOF {
if err := ts.gz.Close(); err != nil {
return 0, err
}
ts.finished = true
return n, nil
}
return n, err
}
ts.currentFile = strings.TrimSuffix(strings.TrimPrefix(currentHeader.Name, "./"), "/")
if err := ts.encodeHeader(currentHeader); err != nil {
return 0, err
}
if err := ts.tarW.WriteHeader(currentHeader); err != nil {
return 0, err
}
if _, err := ts.tarW.Write(buf2[:n]); err != nil {
return 0, err
}
ts.tarW.Flush()
if _, err := io.Copy(ts.gz, ts.bufTar); err != nil {
return 0, err
}
ts.gz.Flush()
return ts.bufGz.Read(buf)
}
return n, err
}
// Filling the hash buffer
if _, err = ts.h.Write(buf2[:n]); err != nil {
return 0, err
}
// Filling the tar writter
if _, err = ts.tarW.Write(buf2[:n]); err != nil {
return 0, err
}
ts.tarW.Flush()
// Filling the gz writter
if _, err = io.Copy(ts.gz, ts.bufTar); err != nil {
return 0, err
}
ts.gz.Flush()
return ts.bufGz.Read(buf)
}