image lookup: do not match *any* tags

For reasons buried in the history of Podman, looking up an untagged
image would match any tag of matching image. For instance, looking up
centos would match a local image centos:foobar.  Change that behavior
to only match the latest tag.

Fix: #11964
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/containerd/stargz-snapshotter/estargz/estargz.go

@@ -118,7 +118,7 @@ func Open(sr *io.SectionReader, opt ...OpenOption) (*Reader, error) {
 		}
 	}
 
-	gzipCompressors := []Decompressor{new(GzipDecompressor), new(legacyGzipDecompressor)}
+	gzipCompressors := []Decompressor{new(GzipDecompressor), new(LegacyGzipDecompressor)}
 	decompressors := append(gzipCompressors, opts.decompressors...)
 
 	// Determine the size to fetch. Try to fetch as many bytes as possible.
@@ -184,7 +184,7 @@ func OpenFooter(sr *io.SectionReader) (tocOffset int64, footerSize int64, rErr e
 		return 0, 0, fmt.Errorf("error reading footer: %v", err)
 	}
 	var allErr []error
-	for _, d := range []Decompressor{new(GzipDecompressor), new(legacyGzipDecompressor)} {
+	for _, d := range []Decompressor{new(GzipDecompressor), new(LegacyGzipDecompressor)} {
 		fSize := d.FooterSize()
 		fOffset := positive(int64(len(footer)) - fSize)
 		_, tocOffset, _, err := d.ParseFooter(footer[fOffset:])
@@ -279,12 +279,12 @@ func (r *Reader) initFields() error {
 		pdir := r.getOrCreateDir(pdirName)
 		ent.NumLink++ // at least one name(ent.Name) references this entry.
 		if ent.Type == "hardlink" {
-			if org, ok := r.m[cleanEntryName(ent.LinkName)]; ok {
-				org.NumLink++ // original entry is referenced by this ent.Name.
-				ent = org
-			} else {
-				return fmt.Errorf("%q is a hardlink but the linkname %q isn't found", ent.Name, ent.LinkName)
+			org, err := r.getSource(ent)
+			if err != nil {
+				return err
 			}
+			org.NumLink++ // original entry is referenced by this ent.Name.
+			ent = org
 		}
 		pdir.addChild(path.Base(name), ent)
 	}
@@ -303,6 +303,20 @@ func (r *Reader) initFields() error {
 	return nil
 }
 
+func (r *Reader) getSource(ent *TOCEntry) (_ *TOCEntry, err error) {
+	if ent.Type == "hardlink" {
+		org, ok := r.m[cleanEntryName(ent.LinkName)]
+		if !ok {
+			return nil, fmt.Errorf("%q is a hardlink but the linkname %q isn't found", ent.Name, ent.LinkName)
+		}
+		ent, err = r.getSource(org)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return ent, nil
+}
+
 func parentDir(p string) string {
 	dir, _ := path.Split(p)
 	return strings.TrimSuffix(dir, "/")
@@ -464,7 +478,11 @@ func (r *Reader) Lookup(path string) (e *TOCEntry, ok bool) {
 	}
 	e, ok = r.m[path]
 	if ok && e.Type == "hardlink" {
-		e, ok = r.m[e.LinkName]
+		var err error
+		e, err = r.getSource(e)
+		if err != nil {
+			return nil, false
+		}
 	}
 	return
 }

vendor/github.com/containerd/stargz-snapshotter/estargz/gzip.go

@@ -38,30 +38,34 @@ import (
 )
 
 type gzipCompression struct {
-	*gzipCompressor
+	*GzipCompressor
 	*GzipDecompressor
 }
 
 func newGzipCompressionWithLevel(level int) Compression {
 	return &gzipCompression{
-		&gzipCompressor{level},
+		&GzipCompressor{level},
 		&GzipDecompressor{},
 	}
 }
 
-func NewGzipCompressorWithLevel(level int) Compressor {
-	return &gzipCompressor{level}
+func NewGzipCompressor() *GzipCompressor {
+	return &GzipCompressor{gzip.BestCompression}
 }
 
-type gzipCompressor struct {
+func NewGzipCompressorWithLevel(level int) *GzipCompressor {
+	return &GzipCompressor{level}
+}
+
+type GzipCompressor struct {
 	compressionLevel int
 }
 
-func (gc *gzipCompressor) Writer(w io.Writer) (io.WriteCloser, error) {
+func (gc *GzipCompressor) Writer(w io.Writer) (io.WriteCloser, error) {
 	return gzip.NewWriterLevel(w, gc.compressionLevel)
 }
 
-func (gc *gzipCompressor) WriteTOCAndFooter(w io.Writer, off int64, toc *JTOC, diffHash hash.Hash) (digest.Digest, error) {
+func (gc *GzipCompressor) WriteTOCAndFooter(w io.Writer, off int64, toc *JTOC, diffHash hash.Hash) (digest.Digest, error) {
 	tocJSON, err := json.MarshalIndent(toc, "", "\t")
 	if err != nil {
 		return "", err
@@ -155,17 +159,21 @@ func (gz *GzipDecompressor) FooterSize() int64 {
 	return FooterSize
 }
 
-type legacyGzipDecompressor struct{}
+func (gz *GzipDecompressor) DecompressTOC(r io.Reader) (tocJSON io.ReadCloser, err error) {
+	return decompressTOCEStargz(r)
+}
 
-func (gz *legacyGzipDecompressor) Reader(r io.Reader) (io.ReadCloser, error) {
+type LegacyGzipDecompressor struct{}
+
+func (gz *LegacyGzipDecompressor) Reader(r io.Reader) (io.ReadCloser, error) {
 	return gzip.NewReader(r)
 }
 
-func (gz *legacyGzipDecompressor) ParseTOC(r io.Reader) (toc *JTOC, tocDgst digest.Digest, err error) {
+func (gz *LegacyGzipDecompressor) ParseTOC(r io.Reader) (toc *JTOC, tocDgst digest.Digest, err error) {
 	return parseTOCEStargz(r)
 }
 
-func (gz *legacyGzipDecompressor) ParseFooter(p []byte) (blobPayloadSize, tocOffset, tocSize int64, err error) {
+func (gz *LegacyGzipDecompressor) ParseFooter(p []byte) (blobPayloadSize, tocOffset, tocSize int64, err error) {
 	if len(p) != legacyFooterSize {
 		return 0, 0, 0, fmt.Errorf("legacy: invalid length %d cannot be parsed", len(p))
 	}
@@ -188,29 +196,43 @@ func (gz *legacyGzipDecompressor) ParseFooter(p []byte) (blobPayloadSize, tocOff
 	return tocOffset, tocOffset, 0, nil
 }
 
-func (gz *legacyGzipDecompressor) FooterSize() int64 {
+func (gz *LegacyGzipDecompressor) FooterSize() int64 {
 	return legacyFooterSize
 }
 
+func (gz *LegacyGzipDecompressor) DecompressTOC(r io.Reader) (tocJSON io.ReadCloser, err error) {
+	return decompressTOCEStargz(r)
+}
+
 func parseTOCEStargz(r io.Reader) (toc *JTOC, tocDgst digest.Digest, err error) {
-	zr, err := gzip.NewReader(r)
+	tr, err := decompressTOCEStargz(r)
 	if err != nil {
-		return nil, "", fmt.Errorf("malformed TOC gzip header: %v", err)
-	}
-	defer zr.Close()
-	zr.Multistream(false)
-	tr := tar.NewReader(zr)
-	h, err := tr.Next()
-	if err != nil {
-		return nil, "", fmt.Errorf("failed to find tar header in TOC gzip stream: %v", err)
-	}
-	if h.Name != TOCTarName {
-		return nil, "", fmt.Errorf("TOC tar entry had name %q; expected %q", h.Name, TOCTarName)
+		return nil, "", err
 	}
 	dgstr := digest.Canonical.Digester()
 	toc = new(JTOC)
 	if err := json.NewDecoder(io.TeeReader(tr, dgstr.Hash())).Decode(&toc); err != nil {
 		return nil, "", fmt.Errorf("error decoding TOC JSON: %v", err)
 	}
+	if err := tr.Close(); err != nil {
+		return nil, "", err
+	}
 	return toc, dgstr.Digest(), nil
 }
+
+func decompressTOCEStargz(r io.Reader) (tocJSON io.ReadCloser, err error) {
+	zr, err := gzip.NewReader(r)
+	if err != nil {
+		return nil, fmt.Errorf("malformed TOC gzip header: %v", err)
+	}
+	zr.Multistream(false)
+	tr := tar.NewReader(zr)
+	h, err := tr.Next()
+	if err != nil {
+		return nil, fmt.Errorf("failed to find tar header in TOC gzip stream: %v", err)
+	}
+	if h.Name != TOCTarName {
+		return nil, fmt.Errorf("TOC tar entry had name %q; expected %q", h.Name, TOCTarName)
+	}
+	return readCloser{tr, zr.Close}, nil
+}