Merge pull request #5761 from thaJeztah/1.4_backport_fix_auth_ua

[release/1.4] Fix incorrect UA used for registry authentication

remotes/docker/authorizer.go

@@ -31,6 +31,7 @@ import (
 
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/log"
+	"github.com/containerd/containerd/version"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/net/context/ctxhttp"
@@ -356,6 +357,9 @@ func (ah *authHandler) fetchTokenWithOAuth(ctx context.Context, to tokenOptions)
 			req.Header[k] = append(req.Header[k], v...)
 		}
 	}
+	if len(req.Header.Get("User-Agent")) == 0 {
+		req.Header.Set("User-Agent", "containerd/"+version.Version)
+	}
 
 	resp, err := ctxhttp.Do(ctx, ah.client, req)
 	if err != nil {
@@ -408,6 +412,9 @@ func (ah *authHandler) fetchToken(ctx context.Context, to tokenOptions) (string,
 			req.Header[k] = append(req.Header[k], v...)
 		}
 	}
+	if len(req.Header.Get("User-Agent")) == 0 {
+		req.Header.Set("User-Agent", "containerd/"+version.Version)
+	}
 
 	reqParams := req.URL.Query()