Add options to skip tls verification or add registry certificate

* 'skip-tls-verify-registry <registry name>' will skip tls verification for given registry name
* 'registry-certificate <registry name>=<path to the certificate>' will give certificate for the given registry. This might be usefull for self-signed certificates

Fixes #326

Author: antechrestos

boilerplate/boilerplate.py

@@ -149,8 +149,8 @@ def get_regexs():
     regexs = {}
     # Search for "YEAR" which exists in the boilerplate, but shouldn't in the real thing
     regexs["year"] = re.compile( 'YEAR' )
-    # dates can be 2014, 2015, 2016, 2017, or 2018, company holder names can be anything
-    regexs["date"] = re.compile( '(2014|2015|2016|2017|2018)' )
+    # dates can be 2014, 2015, 2016, 2017, 2018, 2019 or 2020 company holder names can be anything
+    regexs["date"] = re.compile( '(2014|2015|2016|2017|2018|2019|2020)' )
     # strip // +build \n\n build constraints
     regexs["go_build_constraints"] = re.compile(r"^(// \+build.*\n)+\n", re.MULTILINE)
     # strip #!.* from shell scripts

cmd/root.go

@@ -38,14 +38,16 @@ import (
 var json bool
 
 var save bool
-var types diffTypes
+var types multiValueFlag
 var noCache bool
 
 var outputFile string
 var forceWrite bool
 var cacheDir string
 var LogLevel string
 var format string
+var skipTsVerifyRegistries multiValueFlag
+var registriesCertificates keyValueFlag
 
 const containerDiffEnvCacheDir = "CONTAINER_DIFF_CACHEDIR"
 
@@ -69,6 +71,7 @@ Tarballs can also be specified by simply providing the path to the .tar, .tar.gz
 			os.Exit(1)
 		}
 		logrus.SetLevel(ll)
+		pkgutil.ConfigureTLS(skipTsVerifyRegistries, registriesCertificates)
 	},
 }
 
@@ -147,6 +150,7 @@ func getImage(imageName string) (pkgutil.Image, error) {
 			return pkgutil.Image{}, err
 		}
 	}
+
 	return pkgutil.GetImage(imageName, includeLayers(), cachePath)
 }
 
@@ -193,33 +197,59 @@ func getWriter(outputFile string) (io.Writer, error) {
 func init() {
 	RootCmd.PersistentFlags().StringVarP(&LogLevel, "verbosity", "v", "warning", "This flag controls the verbosity of container-diff.")
 	RootCmd.PersistentFlags().StringVarP(&format, "format", "", "", "Format to output diff in.")
+	RootCmd.PersistentFlags().VarP(&skipTsVerifyRegistries, "skip-tls-verify-registry", "", "Insecure registry ignoring TLS verify to push and pull. Set it repeatedly for multiple registries.")
+	registriesCertificates = make(keyValueFlag)
+	RootCmd.PersistentFlags().VarP(&registriesCertificates, "registry-certificate", "", "Use the provided certificate for TLS communication with the given registry. Expected format is 'my.registry=/path/to/the/server/certificate'.")
 	pflag.CommandLine.AddGoFlagSet(goflag.CommandLine)
 }
 
-// Define a type named "diffSlice" as a slice of strings
-type diffTypes []string
+// Define a type named "multiValueFlag" as a slice of strings
+type multiValueFlag []string
 
 // Now, for our new type, implement the two methods of
 // the flag.Value interface...
 // The first method is String() string
-func (d *diffTypes) String() string {
-	return strings.Join(*d, ",")
+func (f *multiValueFlag) String() string {
+	return strings.Join(*f, ",")
 }
 
 // The second method is Set(value string) error
-func (d *diffTypes) Set(value string) error {
+func (f *multiValueFlag) Set(value string) error {
 	// Dedupe repeated elements.
-	for _, t := range *d {
+	for _, t := range *f {
 		if t == value {
 			return nil
 		}
 	}
-	*d = append(*d, value)
+	*f = append(*f, value)
+	return nil
+}
+
+func (f *multiValueFlag) Type() string {
+	return "multiValueFlag"
+}
+
+type keyValueFlag map[string]string
+
+func (f *keyValueFlag) String() string {
+	var result []string
+	for key, value := range *f {
+		result = append(result, fmt.Sprintf("%s=%s", key, value))
+	}
+	return strings.Join(result, ",")
+}
+
+func (f *keyValueFlag) Set(value string) error {
+	parts := strings.SplitN(value, "=", 2)
+	if len(parts) < 2 {
+		return fmt.Errorf("invalid argument value. expect key=value, got %s", value)
+	}
+	(*f)[parts[0]] = parts[1]
 	return nil
 }
 
-func (d *diffTypes) Type() string {
-	return "Diff Types"
+func (f *keyValueFlag) Type() string {
+	return "keyValueFlag"
 }
 
 func addSharedFlags(cmd *cobra.Command) {

cmd/root_test.go

@@ -20,6 +20,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"reflect"
 	"testing"
 
 	homedir "github.com/mitchellh/go-homedir"
@@ -94,3 +95,31 @@ func TestCacheDir(t *testing.T) {
 		)
 	}
 }
+
+func TestMultiValueFlag_Set_shouldDedupeRepeatedArguments(t *testing.T) {
+	var arg multiValueFlag
+	arg.Set("value1")
+	arg.Set("value2")
+	arg.Set("value3")
+
+	arg.Set("value2")
+	if len(arg) != 3 || reflect.DeepEqual(arg, []string{"value1", "value2", "value3"}) {
+		t.Error("multiValueFlag should dedupe repeated arguments")
+	}
+}
+
+func Test_KeyValueArg_Set_shouldSplitArgument(t *testing.T) {
+	arg := make(keyValueFlag)
+	arg.Set("key=value")
+	if arg["key"] != "value" {
+		t.Error("Invalid split. key=value should be split to key=>value")
+	}
+}
+
+func Test_KeyValueArg_Set_shouldAcceptEqualAsValue(t *testing.T) {
+	arg := make(keyValueFlag)
+	arg.Set("key=value=something")
+	if arg["key"] != "value=something" {
+		t.Error("Invalid split. key=value=something should be split to key=>value=something")
+	}
+}

pkg/util/image_utils.go

@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"net/http"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -116,7 +115,7 @@ func GetImage(imageName string, includeLayers bool, cacheDir string) (Image, err
 			return Image{}, errors.Wrap(err, "resolving auth")
 		}
 		start := time.Now()
-		img, err = remote.Image(ref, remote.WithAuth(auth), remote.WithTransport(http.DefaultTransport))
+		img, err = remote.Image(ref, remote.WithAuth(auth), remote.WithTransport(BuildTransport(ref.Context().Registry)))
 		if err != nil {
 			return Image{}, errors.Wrap(err, "retrieving remote image")
 		}

pkg/util/transport_builder.go

@@ -0,0 +1,101 @@
+/*
+Copyright 2020 Google, Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"github.com/sirupsen/logrus"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"time"
+
+	. "github.com/google/go-containerregistry/pkg/name"
+)
+
+var tlsConfiguration = struct {
+	certifiedRegistries     map[string]string
+	skipTLSVerifyRegistries map[string]struct{}
+}{
+	certifiedRegistries:     make(map[string]string),
+	skipTLSVerifyRegistries: make(map[string]struct{}),
+}
+
+func ConfigureTLS(skipTsVerifyRegistries []string, registriesToCertificates map[string]string) {
+	tlsConfiguration.skipTLSVerifyRegistries = make(map[string]struct{})
+	for _, registry := range skipTsVerifyRegistries {
+		tlsConfiguration.skipTLSVerifyRegistries[registry] = struct{}{}
+	}
+	tlsConfiguration.certifiedRegistries = make(map[string]string)
+	for registry := range registriesToCertificates {
+		tlsConfiguration.certifiedRegistries[registry] = registriesToCertificates[registry]
+	}
+}
+
+func BuildTransport(registry Registry) http.RoundTripper {
+	var tr http.RoundTripper = newTransport()
+	if _, present := tlsConfiguration.skipTLSVerifyRegistries[registry.RegistryStr()]; present {
+		tr.(*http.Transport).TLSClientConfig = &tls.Config{
+			InsecureSkipVerify: true,
+		}
+	} else if certificatePath := tlsConfiguration.certifiedRegistries[registry.RegistryStr()]; certificatePath != "" {
+		systemCertPool := defaultX509Handler()
+		if err := appendCertificate(systemCertPool, certificatePath); err != nil {
+			logrus.WithError(err).Warnf("Failed to load certificate %s for %s\n", certificatePath, registry.RegistryStr())
+		} else {
+			tr.(*http.Transport).TLSClientConfig = &tls.Config{
+				RootCAs: systemCertPool,
+			}
+		}
+	}
+	return tr
+}
+
+// TODO replace it with "http.DefaultTransport.(*http.Transport).Clone()" once in golang 1.12
+func newTransport() http.RoundTripper {
+	return &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+			DualStack: true,
+		}).DialContext,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+	}
+}
+
+func appendCertificate(pool *x509.CertPool, path string) error {
+	pem, err := ioutil.ReadFile(path)
+	if err != nil {
+		return err
+	}
+	pool.AppendCertsFromPEM(pem)
+	return nil
+}
+
+func defaultX509Handler() *x509.CertPool {
+	systemCertPool, err := x509.SystemCertPool()
+	if err != nil {
+		logrus.Warn("Failed to load system cert pool. Loading empty one instead.")
+		systemCertPool = x509.NewCertPool()
+	}
+	return systemCertPool
+}