working commit

pkg/repocli/getman.go

@@ -5,9 +5,12 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"net/http"
 	"strconv"
 	"strings"
+
+	ocidigest "github.com/opencontainers/go-digest"
 )
 
 func (cli *Client) GetManifest(ctx context.Context, rawrepo, tag string) (bool, string, []byte, error) {
@@ -55,36 +58,29 @@ func (cli *Client) GetManifest(ctx context.Context, rawrepo, tag string) (bool,
 		err := fmt.Errorf("Empty MIME type declaration")
 		return exist, mime, man, err
 	}
-	buffer := bytes.NewBuffer(nil)
-	recSize, err := Copy(ctx, buffer, resp.Body)
-	if manSize != recSize {
-		err := fmt.Errorf("Mismatch declared and actual body size, %d and %d", manSize, recSize)
-		return exist, mime, man, err
-	}
-	man = buffer.Bytes()
-
-	csum := resp.Header.Get("Docker-Content-Digest")
-	if csum == "" {
+	digstr := resp.Header.Get("Docker-Content-Digest")
+	if digstr == "" {
 		err := fmt.Errorf("Empty digest declaration")
 		return exist, mime, man, err
 	}
-	csum = strings.ToLower(csum)
-	switch DigestType(csum) {
-	case SHA256:
-		if csum != SHA256Digest(man) {
-			err := fmt.Errorf("Mismatch digest and actual declaration")
-			return exist, mime, man, err
-		}
-	case SHA512:
-		if csum != SHA256Digest(man) {
-			err := fmt.Errorf("Mismatch digest and actual declaration")
-			return exist, mime, man, err
-		}
-	default:
-		err := fmt.Errorf("Unknown digest type: %s", csum)
+	digstr = strings.ToLower(digstr)
+	digobj, err := ocidigest.Parse(digstr)
+	if err != nil {
+		return exist, mime, man, err
+	}
+	verifier := digobj.Verifier()
+	buffer := bytes.NewBuffer(nil)
+	mwriter := io.MultiWriter(buffer, verifier)
+	recSize, err := Copy(ctx, mwriter, resp.Body)
+	if manSize != recSize {
+		err := fmt.Errorf("Mismatch declared and actual size")
+		return exist, mime, man, err
+	}
+	man = buffer.Bytes()
+	if !verifier.Verified() {
+		err := fmt.Errorf("Mismatch digest declaration and actual")
 		return exist, mime, man, err
 	}
-
 	exist = true
 	return exist, mime, man, err
 }