do not crash readXLMetaNoData - if the xl.meta has incorrect content (#14538)

```
tmp = buf[want:]
```

Would potentially crash when `buf` is truncated for some reason
and does not have the expected bytes, this is of course considered
not normal and is an odd situation. But we do not need to crash
here instead allow for errors to be returned and let callers handle
the errors.

cmd/xl-storage-format-v2.go

@@ -658,7 +658,7 @@ func readXLMetaNoData(r io.Reader, size int64) ([]byte, error) {
 	buf := metaDataPoolGet()[:initial]
 	_, err := io.ReadFull(r, buf)
 	if err != nil {
-		return nil, fmt.Errorf("readXLMetaNoData.ReadFull: %w", err)
+		return nil, fmt.Errorf("readXLMetaNoData(io.ReadFull): %w", err)
 	}
 	readMore := func(n int64) error {
 		has := int64(len(buf))
@@ -679,9 +679,9 @@ func readXLMetaNoData(r io.Reader, size int64) ([]byte, error) {
 		if err != nil {
 			if errors.Is(err, io.EOF) {
 				// Returned if we read nothing.
-				return fmt.Errorf("readXLMetaNoData.readMore: %w", io.ErrUnexpectedEOF)
+				err = io.ErrUnexpectedEOF
 			}
-			return fmt.Errorf("readXLMetaNoData.readMore: %w", err)
+			return fmt.Errorf("readXLMetaNoData(readMore): %w", err)
 		}
 		return nil
 	}
@@ -699,7 +699,7 @@ func readXLMetaNoData(r io.Reader, size int64) ([]byte, error) {
 		case 1, 2, 3:
 			sz, tmp, err := msgp.ReadBytesHeader(tmp)
 			if err != nil {
-				return nil, err
+				return nil, fmt.Errorf("readXLMetaNoData(read_meta): uknown metadata version %w", err)
 			}
 			want := int64(sz) + int64(len(buf)-len(tmp))
 
@@ -720,10 +720,14 @@ func readXLMetaNoData(r io.Reader, size int64) ([]byte, error) {
 				return nil, err
 			}
 
+			if int64(len(buf)) < want {
+				return nil, fmt.Errorf("buffer shorter than expected (buflen: %d, want: %d): %w", len(buf), want, errFileCorrupt)
+			}
+
 			tmp = buf[want:]
 			_, after, err := msgp.ReadUint32Bytes(tmp)
 			if err != nil {
-				return nil, err
+				return nil, fmt.Errorf("readXLMetaNoData(read_meta): unknown metadata version %w", err)
 			}
 			want += int64(len(tmp) - len(after))
 

cmd/xl-storage-format-v2_test.go

@@ -18,10 +18,13 @@
 package cmd
 
 import (
+	"bufio"
 	"bytes"
+	"compress/gzip"
 	"encoding/json"
 	"fmt"
 	"io"
+	"os"
 	"sort"
 	"testing"
 	"time"
@@ -34,6 +37,29 @@ import (
 	"github.com/minio/minio/internal/ioutil"
 )
 
+func TestReadXLMetaNoData(t *testing.T) {
+	f, err := os.Open("testdata/xl.meta-corrupt.gz")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+
+	gz, err := gzip.NewReader(bufio.NewReader(f))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	buf, err := io.ReadAll(gz)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = readXLMetaNoData(bytes.NewReader(buf), int64(len(buf)))
+	if err == nil {
+		t.Fatal("expected error but returned success")
+	}
+}
+
 func TestXLV2FormatData(t *testing.T) {
 	failOnErr := func(err error) {
 		t.Helper()

cmd/xl-storage.go

@@ -398,6 +398,9 @@ func (s *xlStorage) readMetadataWithDMTime(ctx context.Context, itemPath string)
 		}
 	}
 	buf, err := readXLMetaNoData(f, stat.Size())
+	if err != nil {
+		return nil, stat.ModTime().UTC(), fmt.Errorf("%w -> %s", err, itemPath)
+	}
 	return buf, stat.ModTime().UTC(), err
 }