DockerCLI/cli/command/trust/sign.go

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package trust
import (
"context"
"fmt"
"io"
"path"
"sort"
"strings"
"github.com/docker/cli/cli"
"github.com/docker/cli/cli/command"
"github.com/docker/cli/cli/command/image"
"github.com/docker/cli/cli/trust"
"github.com/pkg/errors"
"github.com/spf13/cobra"
"github.com/theupdateframework/notary/client"
"github.com/theupdateframework/notary/tuf/data"
)
type signOptions struct {
local bool
imageName string
}
func newSignCommand(dockerCli command.Cli) *cobra.Command {
options := signOptions{}
cmd := &cobra.Command{
Use: "sign IMAGE:TAG",
Short: "Sign an image",
Args: cli.ExactArgs(1),
RunE: func(cmd *cobra.Command, args []string) error {
options.imageName = args[0]
return runSignImage(dockerCli, options)
},
}
flags := cmd.Flags()
flags.BoolVar(&options.local, "local", false, "Sign a locally tagged image")
return cmd
}
func runSignImage(cli command.Cli, options signOptions) error {
imageName := options.imageName
ctx := context.Background()
imgRefAndAuth, err := trust.GetImageReferencesAndAuth(ctx, nil, image.AuthResolver(cli), imageName)
if err != nil {
return err
}
if err := validateTag(imgRefAndAuth); err != nil {
return err
}
notaryRepo, err := cli.NotaryClient(imgRefAndAuth, trust.ActionsPushAndPull)
if err != nil {
return trust.NotaryError(imgRefAndAuth.Reference().Name(), err)
}
if err = clearChangeList(notaryRepo); err != nil {
return err
}
defer clearChangeList(notaryRepo)
// get the latest repository metadata so we can figure out which roles to sign
if _, err = notaryRepo.ListTargets(); err != nil {
switch err.(type) {
case client.ErrRepoNotInitialized, client.ErrRepositoryNotExist:
// before initializing a new repo, check that the image exists locally:
if err := checkLocalImageExistence(ctx, cli, imageName); err != nil {
return err
}
userRole := data.RoleName(path.Join(data.CanonicalTargetsRole.String(), imgRefAndAuth.AuthConfig().Username))
if err := initNotaryRepoWithSigners(notaryRepo, userRole); err != nil {
return trust.NotaryError(imgRefAndAuth.Reference().Name(), err)
}
fmt.Fprintf(cli.Out(), "Created signer: %s\n", imgRefAndAuth.AuthConfig().Username)
fmt.Fprintf(cli.Out(), "Finished initializing signed repository for %s\n", imageName)
default:
return trust.NotaryError(imgRefAndAuth.RepoInfo().Name.Name(), err)
}
}
requestPrivilege := command.RegistryAuthenticationPrivilegedFunc(cli, imgRefAndAuth.RepoInfo().Index, "push")
target, err := createTarget(notaryRepo, imgRefAndAuth.Tag())
if err != nil || options.local {
switch err := err.(type) {
// If the error is nil then the local flag is set
case client.ErrNoSuchTarget, client.ErrRepositoryNotExist, nil:
// Fail fast if the image doesn't exist locally
if err := checkLocalImageExistence(ctx, cli, imageName); err != nil {
return err
}
fmt.Fprintf(cli.Err(), "Signing and pushing trust data for local image %s, may overwrite remote trust data\n", imageName)
return image.TrustedPush(ctx, cli, imgRefAndAuth.RepoInfo(), imgRefAndAuth.Reference(), *imgRefAndAuth.AuthConfig(), requestPrivilege)
default:
return err
}
}
return signAndPublishToTarget(cli.Out(), imgRefAndAuth, notaryRepo, target)
}
func signAndPublishToTarget(out io.Writer, imgRefAndAuth trust.ImageRefAndAuth, notaryRepo client.Repository, target client.Target) error {
tag := imgRefAndAuth.Tag()
fmt.Fprintf(out, "Signing and pushing trust metadata for %s\n", imgRefAndAuth.Name())
existingSigInfo, err := getExistingSignatureInfoForReleasedTag(notaryRepo, tag)
if err != nil {
return err
}
err = image.AddTargetToAllSignableRoles(notaryRepo, &target)
if err == nil {
prettyPrintExistingSignatureInfo(out, existingSigInfo)
err = notaryRepo.Publish()
}
if err != nil {
return errors.Wrapf(err, "failed to sign %s:%s", imgRefAndAuth.RepoInfo().Name.Name(), tag)
}
fmt.Fprintf(out, "Successfully signed %s:%s\n", imgRefAndAuth.RepoInfo().Name.Name(), tag)
return nil
}
func validateTag(imgRefAndAuth trust.ImageRefAndAuth) error {
tag := imgRefAndAuth.Tag()
if tag == "" {
if imgRefAndAuth.Digest() != "" {
return fmt.Errorf("cannot use a digest reference for IMAGE:TAG")
}
return fmt.Errorf("No tag specified for %s", imgRefAndAuth.Name())
}
return nil
}
func checkLocalImageExistence(ctx context.Context, cli command.Cli, imageName string) error {
_, _, err := cli.Client().ImageInspectWithRaw(ctx, imageName)
return err
}
func createTarget(notaryRepo client.Repository, tag string) (client.Target, error) {
target := &client.Target{}
var err error
if tag == "" {
return *target, fmt.Errorf("No tag specified")
}
target.Name = tag
target.Hashes, target.Length, err = getSignedManifestHashAndSize(notaryRepo, tag)
return *target, err
}
func getSignedManifestHashAndSize(notaryRepo client.Repository, tag string) (data.Hashes, int64, error) {
targets, err := notaryRepo.GetAllTargetMetadataByName(tag)
if err != nil {
return nil, 0, err
}
return getReleasedTargetHashAndSize(targets, tag)
}
func getReleasedTargetHashAndSize(targets []client.TargetSignedStruct, tag string) (data.Hashes, int64, error) {
for _, tgt := range targets {
if isReleasedTarget(tgt.Role.Name) {
return tgt.Target.Hashes, tgt.Target.Length, nil
}
}
return nil, 0, client.ErrNoSuchTarget(tag)
}
func getExistingSignatureInfoForReleasedTag(notaryRepo client.Repository, tag string) (trustTagRow, error) {
targets, err := notaryRepo.GetAllTargetMetadataByName(tag)
if err != nil {
return trustTagRow{}, err
}
releasedTargetInfoList := matchReleasedSignatures(targets)
if len(releasedTargetInfoList) == 0 {
return trustTagRow{}, nil
}
return releasedTargetInfoList[0], nil
}
func prettyPrintExistingSignatureInfo(out io.Writer, existingSigInfo trustTagRow) {
sort.Strings(existingSigInfo.Signers)
joinedSigners := strings.Join(existingSigInfo.Signers, ", ")
fmt.Fprintf(out, "Existing signatures for tag %s digest %s from:\n%s\n", existingSigInfo.SignedTag, existingSigInfo.Digest, joinedSigners)
}
func initNotaryRepoWithSigners(notaryRepo client.Repository, newSigner data.RoleName) error {
rootKey, err := getOrGenerateNotaryKey(notaryRepo, data.CanonicalRootRole)
if err != nil {
return err
}
rootKeyID := rootKey.ID()
// Initialize the notary repository with a remotely managed snapshot key
if err := notaryRepo.Initialize([]string{rootKeyID}, data.CanonicalSnapshotRole); err != nil {
return err
}
signerKey, err := getOrGenerateNotaryKey(notaryRepo, newSigner)
if err != nil {
return err
}
if err := addStagedSigner(notaryRepo, newSigner, []data.PublicKey{signerKey}); err != nil {
return errors.Wrapf(err, "could not add signer to repo: %s", strings.TrimPrefix(newSigner.String(), "targets/"))
}
return notaryRepo.Publish()
}
// generates an ECDSA key without a GUN for the specified role
func getOrGenerateNotaryKey(notaryRepo client.Repository, role data.RoleName) (data.PublicKey, error) {
// use the signer name in the PEM headers if this is a delegation key
if data.IsDelegation(role) {
role = data.RoleName(notaryRoleToSigner(role))
}
keys := notaryRepo.GetCryptoService().ListKeys(role)
var err error
var key data.PublicKey
// always select the first key by ID
if len(keys) > 0 {
sort.Strings(keys)
keyID := keys[0]
privKey, _, err := notaryRepo.GetCryptoService().GetPrivateKey(keyID)
if err != nil {
return nil, err
}
key = data.PublicKeyFromPrivate(privKey)
} else {
key, err = notaryRepo.GetCryptoService().Create(role, "", data.ECDSAKey)
if err != nil {
return nil, err
}
}
return key, nil
}
// stages changes to add a signer with the specified name and key(s). Adds to targets/<name> and targets/releases
func addStagedSigner(notaryRepo client.Repository, newSigner data.RoleName, signerKeys []data.PublicKey) error {
// create targets/<username>
if err := notaryRepo.AddDelegationRoleAndKeys(newSigner, signerKeys); err != nil {
return err
}
if err := notaryRepo.AddDelegationPaths(newSigner, []string{""}); err != nil {
return err
}
// create targets/releases
if err := notaryRepo.AddDelegationRoleAndKeys(trust.ReleasesRole, signerKeys); err != nil {
return err
}
return notaryRepo.AddDelegationPaths(trust.ReleasesRole, []string{""})
}