Update auth client configuration to use proper tls config

Currently the http clients used by auth use the default tls config.  The config needs to be updated to only support TLS1.0 and newer as well as respect registry insecure configuration.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

docs/auth.go

@@ -1,6 +1,7 @@
 package registry
 
 import (
+	"crypto/tls"
 	"encoding/base64"
 	"encoding/json"
 	"errors"
@@ -70,10 +71,19 @@ func (auth *RequestAuthorization) getToken() (string, error) {
 		return auth.tokenCache, nil
 	}
 
+	tlsConfig := tls.Config{
+		MinVersion: tls.VersionTLS10,
+	}
+	if !auth.registryEndpoint.IsSecure {
+		tlsConfig.InsecureSkipVerify = true
+	}
+
 	client := &http.Client{
 		Transport: &http.Transport{
 			DisableKeepAlives: true,
-			Proxy:             http.ProxyFromEnvironment},
+			Proxy:             http.ProxyFromEnvironment,
+			TLSClientConfig:   &tlsConfig,
+		},
 		CheckRedirect: AddRequiredHeadersToRedirectedRequests,
 	}
 	factory := HTTPRequestFactory(nil)
@@ -362,10 +372,18 @@ func loginV1(authConfig *AuthConfig, registryEndpoint *Endpoint, factory *utils.
 func loginV2(authConfig *AuthConfig, registryEndpoint *Endpoint, factory *utils.HTTPRequestFactory) (string, error) {
 	log.Debugf("attempting v2 login to registry endpoint %s", registryEndpoint)
 
+	tlsConfig := tls.Config{
+		MinVersion: tls.VersionTLS10,
+	}
+	if !registryEndpoint.IsSecure {
+		tlsConfig.InsecureSkipVerify = true
+	}
+
 	client := &http.Client{
 		Transport: &http.Transport{
 			DisableKeepAlives: true,
 			Proxy:             http.ProxyFromEnvironment,
+			TLSClientConfig:   &tlsConfig,
 		},
 		CheckRedirect: AddRequiredHeadersToRedirectedRequests,
 	}