Revert "Reject symlinks in OCI layout blobs (#2306)"

pkg/v1/layout/blob.go

@@ -15,7 +15,6 @@
 package layout
 
 import (
-	"fmt"
 	"io"
 	"os"
 
@@ -24,56 +23,15 @@ import (
 
 // Blob returns a blob with the given hash from the Path.
 func (l Path) Blob(h v1.Hash) (io.ReadCloser, error) {
-	return l.openBlob(h)
+	return os.Open(l.blobPath(h))
 }
 
 // Bytes is a convenience function to return a blob from the Path as
 // a byte slice.
 func (l Path) Bytes(h v1.Hash) ([]byte, error) {
-	f, err := l.openBlob(h)
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-	return io.ReadAll(f)
+	return os.ReadFile(l.blobPath(h))
 }
 
 func (l Path) blobPath(h v1.Hash) string {
 	return l.path("blobs", h.Algorithm, h.Hex)
 }
-
-func (l Path) openBlob(h v1.Hash) (*os.File, error) {
-	p := l.blobPath(h)
-	info, err := os.Lstat(p)
-	if err != nil {
-		return nil, err
-	}
-	if info.Mode()&os.ModeSymlink != 0 {
-		return nil, fmt.Errorf("layout blob %s is a symlink", h)
-	}
-	if !info.Mode().IsRegular() {
-		return nil, fmt.Errorf("layout blob %s is not a regular file", h)
-	}
-	f, err := os.Open(p)
-	if err != nil {
-		return nil, err
-	}
-	closeFile := true
-	defer func() {
-		if closeFile {
-			f.Close()
-		}
-	}()
-	stat, err := f.Stat()
-	if err != nil {
-		return nil, err
-	}
-	if !stat.Mode().IsRegular() {
-		return nil, fmt.Errorf("layout blob %s is not a regular file", h)
-	}
-	if !os.SameFile(info, stat) {
-		return nil, fmt.Errorf("layout blob %s changed while opening", h)
-	}
-	closeFile = false
-	return f, nil
-}