feat(helm): add --verify flag to commands

This adds the --verify and --keyring flags to:

helm fetch
helm inspect
helm install
helm upgrade

Each of these commands can now make cryptographic verification a
prerequisite for using a chart.

cmd/helm/fetch.go

@@ -17,8 +17,11 @@ limitations under the License.
 package main
 
 import (
+	"bytes"
+	"errors"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"net/http"
 	"net/url"
 	"os"
@@ -27,65 +30,179 @@ import (
 
 	"github.com/spf13/cobra"
 	"k8s.io/helm/pkg/chartutil"
+	"k8s.io/helm/pkg/provenance"
 	"k8s.io/helm/pkg/repo"
 )
 
-var untarFile bool
-var untarDir string
+const fetchDesc = `
+Retrieve a package from a package repository, and download it locally.
 
-func init() {
-	RootCommand.AddCommand(fetchCmd)
-	fetchCmd.Flags().BoolVar(&untarFile, "untar", false, "If set to true, will untar the chart after downloading it.")
-	fetchCmd.Flags().StringVar(&untarDir, "untardir", ".", "If untar is specified, this flag specifies where to untar the chart.")
-}
+This is useful for fetching packages to inspect, modify, or repackage. It can
+also be used to perform cryptographic verification of a chart without installing
+the chart.
+
+There are options for unpacking the chart after download. This will create a
+directory for the chart and uncomparess into that directory.
+
+If the --verify flag is specified, the requested chart MUST have a provenance
+file, and MUST pass the verification process. Failure in any part of this will
+result in an error, and the chart will not be saved locally.
+`
 
-var fetchCmd = &cobra.Command{
-	Use:   "fetch [chart URL | repo/chartname]",
-	Short: "download a chart from a repository and (optionally) unpack it in local directory",
-	Long:  "",
-	RunE:  fetch,
+type fetchCmd struct {
+	untar    bool
+	untardir string
+	chartRef string
+
+	verify  bool
+	keyring string
+
+	out io.Writer
 }
 
-func fetch(cmd *cobra.Command, args []string) error {
-	if len(args) == 0 {
-		return fmt.Errorf("This command needs at least one argument, url or repo/name of the chart.")
+func newFetchCmd(out io.Writer) *cobra.Command {
+	fch := &fetchCmd{out: out}
+
+	cmd := &cobra.Command{
+		Use:   "fetch [chart URL | repo/chartname]",
+		Short: "download a chart from a repository and (optionally) unpack it in local directory",
+		Long:  fetchDesc,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(args) == 0 {
+				return fmt.Errorf("This command needs at least one argument, url or repo/name of the chart.")
+			}
+			fch.chartRef = args[0]
+			return fch.run()
+		},
 	}
 
-	pname := args[0]
+	f := cmd.Flags()
+	f.BoolVar(&fch.untar, "untar", false, "If set to true, will untar the chart after downloading it.")
+	f.StringVar(&fch.untardir, "untardir", ".", "If untar is specified, this flag specifies where to untar the chart.")
+	f.BoolVar(&fch.verify, "verify", false, "Verify the package against its signature.")
+	f.StringVar(&fch.keyring, "keyring", defaultKeyring(), "The keyring containing public keys.")
+
+	return cmd
+}
+
+func (f *fetchCmd) run() error {
+	pname := f.chartRef
 	if filepath.Ext(pname) != ".tgz" {
 		pname += ".tgz"
 	}
-	return fetchChart(pname)
 
+	return downloadChart(pname, f.untar, f.untardir, f.verify, f.keyring)
 }
 
-func fetchChart(pname string) error {
-
-	f, err := repo.LoadRepositoriesFile(repositoriesFile())
+// downloadChart fetches a chart over HTTP, and then (if verify is true) verifies it.
+//
+// If untar is true, it also unpacks the file into untardir.
+func downloadChart(pname string, untar bool, untardir string, verify bool, keyring string) error {
+	r, err := repo.LoadRepositoriesFile(repositoriesFile())
 	if err != nil {
 		return err
 	}
 
 	// get download url
-	u, err := mapRepoArg(pname, f.Repositories)
+	u, err := mapRepoArg(pname, r.Repositories)
 	if err != nil {
 		return err
 	}
 
-	resp, err := http.Get(u.String())
+	href := u.String()
+	buf, err := fetchChart(href)
 	if err != nil {
 		return err
 	}
-	if resp.StatusCode != 200 {
-		return fmt.Errorf("Failed to fetch %s : %s", u.String(), resp.Status)
+
+	if verify {
+		basename := filepath.Base(pname)
+		sigref := href + ".prov"
+		sig, err := fetchChart(sigref)
+		if err != nil {
+			return fmt.Errorf("provenance data not downloaded from %s: %s", sigref, err)
+		}
+		if err := ioutil.WriteFile(basename+".prov", sig.Bytes(), 0755); err != nil {
+			return fmt.Errorf("provenance data not saved: %s", err)
+		}
+		if err := verifyChart(basename, keyring); err != nil {
+			return err
+		}
 	}
 
-	defer resp.Body.Close()
-	if untarFile {
-		return chartutil.Expand(untarDir, resp.Body)
+	return saveChart(pname, buf, untar, untardir)
+}
+
+// verifyChart takes a path to a chart archive and a keyring, and verifies the chart.
+//
+// It assumes that a chart archive file is accompanied by a provenance file whose
+// name is the archive file name plus the ".prov" extension.
+func verifyChart(path string, keyring string) error {
+	// For now, error out if it's not a tar file.
+	if fi, err := os.Stat(path); err != nil {
+		return err
+	} else if fi.IsDir() {
+		return errors.New("unpacked charts cannot be verified")
+	} else if !isTar(path) {
+		return errors.New("chart must be a tgz file")
 	}
-	p := strings.Split(u.String(), "/")
-	return saveChartFile(p[len(p)-1], resp.Body)
+
+	provfile := path + ".prov"
+	if _, err := os.Stat(provfile); err != nil {
+		return fmt.Errorf("could not load provenance file %s: %s", provfile, err)
+	}
+
+	sig, err := provenance.NewFromKeyring(keyring, "")
+	if err != nil {
+		return fmt.Errorf("failed to load keyring: %s", err)
+	}
+	ver, err := sig.Verify(path, provfile)
+	if flagDebug {
+		for name := range ver.SignedBy.Identities {
+			fmt.Printf("Signed by %q\n", name)
+		}
+	}
+	return err
+}
+
+// defaultKeyring returns the expanded path to the default keyring.
+func defaultKeyring() string {
+	return os.ExpandEnv("$HOME/.gnupg/pubring.gpg")
+}
+
+// isTar tests whether the given file is a tar file.
+//
+// Currently, this simply checks extension, since a subsequent function will
+// untar the file and validate its binary format.
+func isTar(filename string) bool {
+	return strings.ToLower(filepath.Ext(filename)) == ".tgz"
+}
+
+// saveChart saves a chart locally.
+func saveChart(name string, buf *bytes.Buffer, untar bool, untardir string) error {
+	if untar {
+		return chartutil.Expand(untardir, buf)
+	}
+
+	p := strings.Split(name, "/")
+	return saveChartFile(p[len(p)-1], buf)
+}
+
+// fetchChart retrieves a chart over HTTP.
+func fetchChart(href string) (*bytes.Buffer, error) {
+	buf := bytes.NewBuffer(nil)
+
+	resp, err := http.Get(href)
+	if err != nil {
+		return buf, err
+	}
+	if resp.StatusCode != 200 {
+		return buf, fmt.Errorf("Failed to fetch %s : %s", href, resp.Status)
+	}
+
+	_, err = io.Copy(buf, resp.Body)
+	resp.Body.Close()
+	return buf, err
 }
 
 // mapRepoArg figures out which format the argument is given, and creates a fetchable

cmd/helm/helm.go

@@ -95,6 +95,8 @@ func newRootCmd(out io.Writer) *cobra.Command {
 		newUpgradeCmd(nil, out),
 		newRollbackCmd(nil, out),
 		newPackageCmd(nil, out),
+		newFetchCmd(out),
+		newVerifyCmd(out),
 	)
 	return cmd
 }

cmd/helm/inspect.go

@@ -46,6 +46,8 @@ of the Charts.yaml file
 type inspectCmd struct {
 	chartpath string
 	output    string
+	verify    bool
+	keyring   string
 	out       io.Writer
 	client    helm.Interface
 }
@@ -71,7 +73,7 @@ func newInspectCmd(c helm.Interface, out io.Writer) *cobra.Command {
 			if err := checkArgsLength(1, len(args), "chart name"); err != nil {
 				return err
 			}
-			cp, err := locateChartPath(args[0])
+			cp, err := locateChartPath(args[0], insp.verify, insp.keyring)
 			if err != nil {
 				return err
 			}
@@ -86,7 +88,7 @@ func newInspectCmd(c helm.Interface, out io.Writer) *cobra.Command {
 		Long:  inspectValuesDesc,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			insp.output = valuesOnly
-			cp, err := locateChartPath(args[0])
+			cp, err := locateChartPath(args[0], insp.verify, insp.keyring)
 			if err != nil {
 				return err
 			}
@@ -101,7 +103,7 @@ func newInspectCmd(c helm.Interface, out io.Writer) *cobra.Command {
 		Long:  inspectChartDesc,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			insp.output = chartOnly
-			cp, err := locateChartPath(args[0])
+			cp, err := locateChartPath(args[0], insp.verify, insp.keyring)
 			if err != nil {
 				return err
 			}
@@ -110,6 +112,19 @@ func newInspectCmd(c helm.Interface, out io.Writer) *cobra.Command {
 		},
 	}
 
+	vflag := "verify"
+	vdesc := "verify the provenance data for this chart"
+	inspectCommand.Flags().BoolVar(&insp.verify, vflag, false, vdesc)
+	valuesSubCmd.Flags().BoolVar(&insp.verify, vflag, false, vdesc)
+	chartSubCmd.Flags().BoolVar(&insp.verify, vflag, false, vdesc)
+
+	kflag := "keyring"
+	kdesc := "the path to the keyring containing public verification keys"
+	kdefault := defaultKeyring()
+	inspectCommand.Flags().StringVar(&insp.keyring, kflag, kdefault, kdesc)
+	valuesSubCmd.Flags().StringVar(&insp.keyring, kflag, kdefault, kdesc)
+	chartSubCmd.Flags().StringVar(&insp.keyring, kflag, kdefault, kdesc)
+
 	inspectCommand.AddCommand(valuesSubCmd)
 	inspectCommand.AddCommand(chartSubCmd)
 

cmd/helm/install.go

@@ -18,6 +18,7 @@ package main
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -54,6 +55,9 @@ or
 To check the generated manifests of a release without installing the chart,
 the '--debug' and '--dry-run' flags can be combined. This will still require a
 round-trip to the Tiller server.
+
+If --verify is set, the chart MUST have a provenance file, and the provenenace
+fall MUST pass all verification steps.
 `
 
 type installCmd struct {
@@ -64,6 +68,8 @@ type installCmd struct {
 	dryRun       bool
 	disableHooks bool
 	replace      bool
+	verify       bool
+	keyring      string
 	out          io.Writer
 	client       helm.Interface
 	values       *values
@@ -86,7 +92,7 @@ func newInstallCmd(c helm.Interface, out io.Writer) *cobra.Command {
 			if err := checkArgsLength(1, len(args), "chart name"); err != nil {
 				return err
 			}
-			cp, err := locateChartPath(args[0])
+			cp, err := locateChartPath(args[0], inst.verify, inst.keyring)
 			if err != nil {
 				return err
 			}
@@ -106,6 +112,8 @@ func newInstallCmd(c helm.Interface, out io.Writer) *cobra.Command {
 	f.BoolVar(&inst.replace, "replace", false, "re-use the given name, even if that name is already used. This is unsafe in production")
 	f.Var(inst.values, "set", "set values on the command line. Separate values with commas: key1=val1,key2=val2")
 	f.StringVar(&inst.nameTemplate, "name-template", "", "specify template used to name the release")
+	f.BoolVar(&inst.verify, "verify", false, "verify the package before installing it")
+	f.StringVar(&inst.keyring, "keyring", defaultKeyring(), "location of public keys used for verification")
 	return cmd
 }
 
@@ -171,6 +179,7 @@ func (i *installCmd) vals() ([]byte, error) {
 	return buffer.Bytes(), nil
 }
 
+// printRelease prints info about a release if the flagDebug is true.
 func (i *installCmd) printRelease(rel *release.Release) {
 	if rel == nil {
 		return
@@ -251,9 +260,23 @@ func splitPair(item string) (name string, value interface{}) {
 // - current working directory
 // - if path is absolute or begins with '.', error out here
 // - chart repos in $HELM_HOME
-func locateChartPath(name string) (string, error) {
-	if _, err := os.Stat(name); err == nil {
-		return filepath.Abs(name)
+//
+// If 'verify' is true, this will attempt to also verify the chart.
+func locateChartPath(name string, verify bool, keyring string) (string, error) {
+	if fi, err := os.Stat(name); err == nil {
+		abs, err := filepath.Abs(name)
+		if err != nil {
+			return abs, err
+		}
+		if verify {
+			if fi.IsDir() {
+				return "", errors.New("cannot verify a directory")
+			}
+			if err := verifyChart(abs, keyring); err != nil {
+				return "", err
+			}
+		}
+		return abs, nil
 	}
 	if filepath.IsAbs(name) || strings.HasPrefix(name, ".") {
 		return name, fmt.Errorf("path %q not found", name)
@@ -269,7 +292,7 @@ func locateChartPath(name string) (string, error) {
 	if filepath.Ext(name) != ".tgz" {
 		name += ".tgz"
 	}
-	if err := fetchChart(name); err == nil {
+	if err := downloadChart(name, false, ".", verify, keyring); err == nil {
 		lname, err := filepath.Abs(filepath.Base(name))
 		if err != nil {
 			return lname, err

cmd/helm/install_test.go

@@ -74,6 +74,24 @@ func TestInstall(t *testing.T) {
 			expected: "FOOBAR",
 			resp:     releaseMock(&releaseOptions{name: "FOOBAR"}),
 		},
+		// Install, perform chart verification along the way.
+		{
+			name:  "install with verification, missing provenance",
+			args:  []string{"testdata/testcharts/compressedchart-0.1.0.tgz"},
+			flags: strings.Split("--verify --keyring testdata/helm-test-key.pub", " "),
+			err:   true,
+		},
+		{
+			name:  "install with verification, directory instead of file",
+			args:  []string{"testdata/testcharts/signtest"},
+			flags: strings.Split("--verify --keyring testdata/helm-test-key.pub", " "),
+			err:   true,
+		},
+		{
+			name:  "install with verification, valid",
+			args:  []string{"testdata/testcharts/signtest-0.1.0.tgz"},
+			flags: strings.Split("--verify --keyring testdata/helm-test-key.pub", " "),
+		},
 	}
 
 	runReleaseCases(t, tests, func(c *fakeReleaseClient, out io.Writer) *cobra.Command {

cmd/helm/list_test.go

@@ -28,7 +28,6 @@ func TestListCmd(t *testing.T) {
 	tests := []struct {
 		name     string
 		args     []string
-		flags    map[string]string
 		resp     []*release.Release
 		expected string
 		err      bool
@@ -41,8 +40,9 @@ func TestListCmd(t *testing.T) {
 			expected: "thomas-guide",
 		},
 		{
-			name:  "list --long",
-			flags: map[string]string{"long": "1"},
+			name: "list --long",
+			//flags: map[string]string{"long": "1"},
+			args: []string{"--long"},
 			resp: []*release.Release{
 				releaseMock(&releaseOptions{name: "atlas"}),
 			},
@@ -56,7 +56,7 @@ func TestListCmd(t *testing.T) {
 			rels: tt.resp,
 		}
 		cmd := newListCmd(c, &buf)
-		setFlags(cmd, tt.flags)
+		cmd.ParseFlags(tt.args)
 		err := cmd.RunE(cmd, tt.args)
 		if (err != nil) != tt.err {
 			t.Errorf("%q. expected error: %v, got %v", tt.name, tt.err, err)

cmd/helm/package.go

@@ -43,11 +43,6 @@ Chart.yaml file, and (if found) build the current directory into a chart.
 Versioned chart archives are used by Helm package repositories.
 `
 
-const (
-	envSigningKey = "HELM_SIGNING_KEY"
-	envKeyring    = "HELM_KEYRING"
-)
-
 type packageCmd struct {
 	save    bool
 	sign    bool
@@ -86,7 +81,7 @@ func newPackageCmd(client helm.Interface, out io.Writer) *cobra.Command {
 	f.BoolVar(&pkg.save, "save", true, "save packaged chart to local chart repository")
 	f.BoolVar(&pkg.sign, "sign", false, "use a PGP private key to sign this package")
 	f.StringVar(&pkg.key, "key", "", "the name of the key to use when signing. Used if --sign is true.")
-	f.StringVar(&pkg.keyring, "keyring", os.ExpandEnv("$HOME/.gnupg/pubring.gpg"), "the location of a public keyring")
+	f.StringVar(&pkg.keyring, "keyring", defaultKeyring(), "the location of a public keyring")
 
 	return cmd
 }

cmd/helm/testdata/testcharts/signtest-0.1.0.tgz.prov

+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA512
+
+description: A Helm chart for Kubernetes
+name: signtest
+version: 0.1.0
+
+...
+files:
+  signtest-0.1.0.tgz: sha256:dee72947753628425b82814516bdaa37aef49f25e8820dd2a6e15a33a007823b
+-----BEGIN PGP SIGNATURE-----
+
+wsBcBAEBCgAQBQJXomNHCRCEO7+YH8GHYgAALywIAG1Me852Fpn1GYu8Q1GCcw4g
+l2k7vOFchdDwDhdSVbkh4YyvTaIO3iE2Jtk1rxw+RIJiUr0eLO/rnIJuxZS8WKki
+DR1LI9J1VD4dxN3uDETtWDWq7ScoPsRY5mJvYZXC8whrWEt/H2kfqmoA9LloRPWp
+flOE0iktA4UciZOblTj6nAk3iDyjh/4HYL4a6tT0LjjKI7OTw4YyHfjHad1ywVCz
+9dMUc1rPgTnl+fnRiSPSrlZIWKOt1mcQ4fVrU3nwtRUwTId2k8FtygL0G6M+Y6t0
+S6yaU7qfk9uTxkdkUF7Bf1X3ukxfe+cNBC32vf4m8LY4NkcYfSqK2fGtQsnVr6s=
+=NyOM
+-----END PGP SIGNATURE-----
\ No newline at end of file

cmd/helm/testdata/testcharts/signtest/.helmignore

+# Patterns to ignore when building packages.
+# This supports shell glob matching, relative path matching, and
+# negation (prefixed with !). Only one pattern per line.
+.DS_Store
+.git

cmd/helm/testdata/testcharts/signtest/Chart.yaml

+description: A Helm chart for Kubernetes
+name: signtest
+version: 0.1.0

cmd/helm/testdata/testcharts/signtest/alpine/Chart.yaml

+description: Deploy a basic Alpine Linux pod
+home: https://k8s.io/helm
+name: alpine
+sources:
+- https://github.com/kubernetes/helm
+version: 0.1.0

cmd/helm/testdata/testcharts/signtest/alpine/README.md

+This example was generated using the command `helm create alpine`.
+
+The `templates/` directory contains a very simple pod resource with a
+couple of parameters.
+
+The `values.yaml` file contains the default values for the
+`alpine-pod.yaml` template.
+
+You can install this example using `helm install docs/examples/alpine`.

cmd/helm/testdata/testcharts/signtest/alpine/templates/alpine-pod.yaml

+apiVersion: v1
+kind: Pod
+metadata:
+  name: {{.Release.Name}}-{{.Chart.Name}}
+  labels:
+    heritage: {{.Release.Service}}
+    chartName: {{.Chart.Name}}
+    chartVersion: {{.Chart.Version | quote}}
+  annotations:
+    "helm.sh/created": "{{.Release.Time.Seconds}}"
+spec:
+  restartPolicy: {{default "Never" .restart_policy}}
+  containers:
+  - name: waiter
+    image: "alpine:3.3"
+    command: ["/bin/sleep","9000"]

cmd/helm/testdata/testcharts/signtest/alpine/values.yaml

+# The pod name
+name: my-alpine

cmd/helm/testdata/testcharts/signtest/templates/pod.yaml

+apiVersion: v1
+kind: Pod
+metadata:
+  name: signtest
+spec:
+  restartPolicy: Never
+  containers:
+  - name: waiter
+    image: "alpine:3.3"
+    command: ["/bin/sleep","9000"]

cmd/helm/upgrade.go

@@ -46,6 +46,8 @@ type upgradeCmd struct {
 	disableHooks bool
 	valuesFile   string
 	values       *values
+	verify       bool
+	keyring      string
 }
 
 func newUpgradeCmd(client helm.Interface, out io.Writer) *cobra.Command {
@@ -79,6 +81,8 @@ func newUpgradeCmd(client helm.Interface, out io.Writer) *cobra.Command {
 	f.BoolVar(&upgrade.dryRun, "dry-run", false, "simulate an upgrade")
 	f.Var(upgrade.values, "set", "set values on the command line. Separate values with commas: key1=val1,key2=val2")
 	f.BoolVar(&upgrade.disableHooks, "disable-hooks", false, "disable pre/post upgrade hooks")
+	f.BoolVar(&upgrade.verify, "verify", false, "verify the provenance of the chart before upgrading")
+	f.StringVar(&upgrade.keyring, "keyring", defaultKeyring(), "the path to the keyring that contains public singing keys")
 
 	return cmd
 }
@@ -109,7 +113,7 @@ func (u *upgradeCmd) vals() ([]byte, error) {
 }
 
 func (u *upgradeCmd) run() error {
-	chartPath, err := locateChartPath(u.chart)
+	chartPath, err := locateChartPath(u.chart, u.verify, u.keyring)
 	if err != nil {
 		return err
 	}

cmd/helm/verify.go

+/*
+Copyright 2016 The Kubernetes Authors 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 main
+
+import (
+	"errors"
+	"io"
+
+	"github.com/spf13/cobra"
+)
+
+const verifyDesc = `
+Verify that the given chart has a valid provenance file.
+
+Provenance files provide crytographic verification that a chart has not been
+tampered with, and was packaged by a trusted provider.
+
+This command can be used to verify a local chart. Several other commands provide
+'--verify' flags that run the same validation. To generate a signed package, use
+the 'helm package --sign' command.
+`
+
+type verifyCmd struct {
+	keyring   string
+	chartfile string
+
+	out io.Writer
+}
+
+func newVerifyCmd(out io.Writer) *cobra.Command {
+	vc := &verifyCmd{out: out}
+
+	cmd := &cobra.Command{
+		Use:   "verify [flags] PATH",
+		Short: "verify that a chart at the given path has been signed and is valid",
+		Long:  verifyDesc,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(args) == 0 {
+				return errors.New("a path to a package file is required")
+			}
+			vc.chartfile = args[0]
+			return vc.run()
+		},
+	}
+
+	f := cmd.Flags()
+	f.StringVar(&vc.keyring, "keyring", defaultKeyring(), "the keyring containing public keys.")
+
+	return cmd
+}
+
+func (v *verifyCmd) run() error {
+	return verifyChart(v.chartfile, v.keyring)
+}