github.com/zhuohuang-hust/src-cbuild@v0.0.0-20230105071821-c7aab3e7c840/cli/command/image/trust.go (about)

     1  package image
     2  
     3  import (
     4  	"encoding/hex"
     5  	"encoding/json"
     6  	"errors"
     7  	"fmt"
     8  	"io"
     9  	"net"
    10  	"net/http"
    11  	"net/url"
    12  	"os"
    13  	"path"
    14  	"path/filepath"
    15  	"sort"
    16  	"time"
    17  
    18  	"golang.org/x/net/context"
    19  
    20  	"github.com/Sirupsen/logrus"
    21  	"github.com/docker/distribution/digest"
    22  	"github.com/docker/distribution/registry/client/auth"
    23  	"github.com/docker/distribution/registry/client/auth/challenge"
    24  	"github.com/docker/distribution/registry/client/transport"
    25  	"github.com/docker/docker/api/types"
    26  	registrytypes "github.com/docker/docker/api/types/registry"
    27  	"github.com/docker/docker/cli/command"
    28  	"github.com/docker/docker/cliconfig"
    29  	"github.com/docker/docker/distribution"
    30  	"github.com/docker/docker/pkg/jsonmessage"
    31  	"github.com/docker/docker/reference"
    32  	"github.com/docker/docker/registry"
    33  	"github.com/docker/go-connections/tlsconfig"
    34  	"github.com/docker/notary"
    35  	"github.com/docker/notary/client"
    36  	"github.com/docker/notary/passphrase"
    37  	"github.com/docker/notary/storage"
    38  	"github.com/docker/notary/trustmanager"
    39  	"github.com/docker/notary/trustpinning"
    40  	"github.com/docker/notary/tuf/data"
    41  	"github.com/docker/notary/tuf/signed"
    42  )
    43  
    44  var (
    45  	releasesRole = path.Join(data.CanonicalTargetsRole, "releases")
    46  )
    47  
    48  type target struct {
    49  	name   string
    50  	digest digest.Digest
    51  	size   int64
    52  }
    53  
    54  // trustedPush handles content trust pushing of an image
    55  func trustedPush(ctx context.Context, cli *command.DockerCli, repoInfo *registry.RepositoryInfo, ref reference.Named, authConfig types.AuthConfig, requestPrivilege types.RequestPrivilegeFunc) error {
    56  	responseBody, err := imagePushPrivileged(ctx, cli, authConfig, ref.String(), requestPrivilege)
    57  	if err != nil {
    58  		return err
    59  	}
    60  
    61  	defer responseBody.Close()
    62  
    63  	// If it is a trusted push we would like to find the target entry which match the
    64  	// tag provided in the function and then do an AddTarget later.
    65  	target := &client.Target{}
    66  	// Count the times of calling for handleTarget,
    67  	// if it is called more that once, that should be considered an error in a trusted push.
    68  	cnt := 0
    69  	handleTarget := func(aux *json.RawMessage) {
    70  		cnt++
    71  		if cnt > 1 {
    72  			// handleTarget should only be called one. This will be treated as an error.
    73  			return
    74  		}
    75  
    76  		var pushResult distribution.PushResult
    77  		err := json.Unmarshal(*aux, &pushResult)
    78  		if err == nil && pushResult.Tag != "" && pushResult.Digest.Validate() == nil {
    79  			h, err := hex.DecodeString(pushResult.Digest.Hex())
    80  			if err != nil {
    81  				target = nil
    82  				return
    83  			}
    84  			target.Name = pushResult.Tag
    85  			target.Hashes = data.Hashes{string(pushResult.Digest.Algorithm()): h}
    86  			target.Length = int64(pushResult.Size)
    87  		}
    88  	}
    89  
    90  	var tag string
    91  	switch x := ref.(type) {
    92  	case reference.Canonical:
    93  		return errors.New("cannot push a digest reference")
    94  	case reference.NamedTagged:
    95  		tag = x.Tag()
    96  	default:
    97  		// We want trust signatures to always take an explicit tag,
    98  		// otherwise it will act as an untrusted push.
    99  		if err = jsonmessage.DisplayJSONMessagesToStream(responseBody, cli.Out(), nil); err != nil {
   100  			return err
   101  		}
   102  		fmt.Fprintln(cli.Out(), "No tag specified, skipping trust metadata push")
   103  		return nil
   104  	}
   105  
   106  	if err = jsonmessage.DisplayJSONMessagesToStream(responseBody, cli.Out(), handleTarget); err != nil {
   107  		return err
   108  	}
   109  
   110  	if cnt > 1 {
   111  		return fmt.Errorf("internal error: only one call to handleTarget expected")
   112  	}
   113  
   114  	if target == nil {
   115  		fmt.Fprintln(cli.Out(), "No targets found, please provide a specific tag in order to sign it")
   116  		return nil
   117  	}
   118  
   119  	fmt.Fprintln(cli.Out(), "Signing and pushing trust metadata")
   120  
   121  	repo, err := GetNotaryRepository(cli, repoInfo, authConfig, "push", "pull")
   122  	if err != nil {
   123  		fmt.Fprintf(cli.Out(), "Error establishing connection to notary repository: %s\n", err)
   124  		return err
   125  	}
   126  
   127  	// get the latest repository metadata so we can figure out which roles to sign
   128  	err = repo.Update(false)
   129  
   130  	switch err.(type) {
   131  	case client.ErrRepoNotInitialized, client.ErrRepositoryNotExist:
   132  		keys := repo.CryptoService.ListKeys(data.CanonicalRootRole)
   133  		var rootKeyID string
   134  		// always select the first root key
   135  		if len(keys) > 0 {
   136  			sort.Strings(keys)
   137  			rootKeyID = keys[0]
   138  		} else {
   139  			rootPublicKey, err := repo.CryptoService.Create(data.CanonicalRootRole, "", data.ECDSAKey)
   140  			if err != nil {
   141  				return err
   142  			}
   143  			rootKeyID = rootPublicKey.ID()
   144  		}
   145  
   146  		// Initialize the notary repository with a remotely managed snapshot key
   147  		if err := repo.Initialize([]string{rootKeyID}, data.CanonicalSnapshotRole); err != nil {
   148  			return notaryError(repoInfo.FullName(), err)
   149  		}
   150  		fmt.Fprintf(cli.Out(), "Finished initializing %q\n", repoInfo.FullName())
   151  		err = repo.AddTarget(target, data.CanonicalTargetsRole)
   152  	case nil:
   153  		// already initialized and we have successfully downloaded the latest metadata
   154  		err = addTargetToAllSignableRoles(repo, target)
   155  	default:
   156  		return notaryError(repoInfo.FullName(), err)
   157  	}
   158  
   159  	if err == nil {
   160  		err = repo.Publish()
   161  	}
   162  
   163  	if err != nil {
   164  		fmt.Fprintf(cli.Out(), "Failed to sign %q:%s - %s\n", repoInfo.FullName(), tag, err.Error())
   165  		return notaryError(repoInfo.FullName(), err)
   166  	}
   167  
   168  	fmt.Fprintf(cli.Out(), "Successfully signed %q:%s\n", repoInfo.FullName(), tag)
   169  	return nil
   170  }
   171  
   172  // Attempt to add the image target to all the top level delegation roles we can
   173  // (based on whether we have the signing key and whether the role's path allows
   174  // us to).
   175  // If there are no delegation roles, we add to the targets role.
   176  func addTargetToAllSignableRoles(repo *client.NotaryRepository, target *client.Target) error {
   177  	var signableRoles []string
   178  
   179  	// translate the full key names, which includes the GUN, into just the key IDs
   180  	allCanonicalKeyIDs := make(map[string]struct{})
   181  	for fullKeyID := range repo.CryptoService.ListAllKeys() {
   182  		allCanonicalKeyIDs[path.Base(fullKeyID)] = struct{}{}
   183  	}
   184  
   185  	allDelegationRoles, err := repo.GetDelegationRoles()
   186  	if err != nil {
   187  		return err
   188  	}
   189  
   190  	// if there are no delegation roles, then just try to sign it into the targets role
   191  	if len(allDelegationRoles) == 0 {
   192  		return repo.AddTarget(target, data.CanonicalTargetsRole)
   193  	}
   194  
   195  	// there are delegation roles, find every delegation role we have a key for, and
   196  	// attempt to sign into into all those roles.
   197  	for _, delegationRole := range allDelegationRoles {
   198  		// We do not support signing any delegation role that isn't a direct child of the targets role.
   199  		// Also don't bother checking the keys if we can't add the target
   200  		// to this role due to path restrictions
   201  		if path.Dir(delegationRole.Name) != data.CanonicalTargetsRole || !delegationRole.CheckPaths(target.Name) {
   202  			continue
   203  		}
   204  
   205  		for _, canonicalKeyID := range delegationRole.KeyIDs {
   206  			if _, ok := allCanonicalKeyIDs[canonicalKeyID]; ok {
   207  				signableRoles = append(signableRoles, delegationRole.Name)
   208  				break
   209  			}
   210  		}
   211  	}
   212  
   213  	if len(signableRoles) == 0 {
   214  		return fmt.Errorf("no valid signing keys for delegation roles")
   215  	}
   216  
   217  	return repo.AddTarget(target, signableRoles...)
   218  }
   219  
   220  // imagePushPrivileged push the image
   221  func imagePushPrivileged(ctx context.Context, cli *command.DockerCli, authConfig types.AuthConfig, ref string, requestPrivilege types.RequestPrivilegeFunc) (io.ReadCloser, error) {
   222  	encodedAuth, err := command.EncodeAuthToBase64(authConfig)
   223  	if err != nil {
   224  		return nil, err
   225  	}
   226  	options := types.ImagePushOptions{
   227  		RegistryAuth:  encodedAuth,
   228  		PrivilegeFunc: requestPrivilege,
   229  	}
   230  
   231  	return cli.Client().ImagePush(ctx, ref, options)
   232  }
   233  
   234  // trustedPull handles content trust pulling of an image
   235  func trustedPull(ctx context.Context, cli *command.DockerCli, repoInfo *registry.RepositoryInfo, ref reference.Named, authConfig types.AuthConfig, requestPrivilege types.RequestPrivilegeFunc) error {
   236  	var refs []target
   237  
   238  	notaryRepo, err := GetNotaryRepository(cli, repoInfo, authConfig, "pull")
   239  	if err != nil {
   240  		fmt.Fprintf(cli.Out(), "Error establishing connection to trust repository: %s\n", err)
   241  		return err
   242  	}
   243  
   244  	if tagged, isTagged := ref.(reference.NamedTagged); !isTagged {
   245  		// List all targets
   246  		targets, err := notaryRepo.ListTargets(releasesRole, data.CanonicalTargetsRole)
   247  		if err != nil {
   248  			return notaryError(repoInfo.FullName(), err)
   249  		}
   250  		for _, tgt := range targets {
   251  			t, err := convertTarget(tgt.Target)
   252  			if err != nil {
   253  				fmt.Fprintf(cli.Out(), "Skipping target for %q\n", repoInfo.Name())
   254  				continue
   255  			}
   256  			// Only list tags in the top level targets role or the releases delegation role - ignore
   257  			// all other delegation roles
   258  			if tgt.Role != releasesRole && tgt.Role != data.CanonicalTargetsRole {
   259  				continue
   260  			}
   261  			refs = append(refs, t)
   262  		}
   263  		if len(refs) == 0 {
   264  			return notaryError(repoInfo.FullName(), fmt.Errorf("No trusted tags for %s", repoInfo.FullName()))
   265  		}
   266  	} else {
   267  		t, err := notaryRepo.GetTargetByName(tagged.Tag(), releasesRole, data.CanonicalTargetsRole)
   268  		if err != nil {
   269  			return notaryError(repoInfo.FullName(), err)
   270  		}
   271  		// Only get the tag if it's in the top level targets role or the releases delegation role
   272  		// ignore it if it's in any other delegation roles
   273  		if t.Role != releasesRole && t.Role != data.CanonicalTargetsRole {
   274  			return notaryError(repoInfo.FullName(), fmt.Errorf("No trust data for %s", tagged.Tag()))
   275  		}
   276  
   277  		logrus.Debugf("retrieving target for %s role\n", t.Role)
   278  		r, err := convertTarget(t.Target)
   279  		if err != nil {
   280  			return err
   281  
   282  		}
   283  		refs = append(refs, r)
   284  	}
   285  
   286  	for i, r := range refs {
   287  		displayTag := r.name
   288  		if displayTag != "" {
   289  			displayTag = ":" + displayTag
   290  		}
   291  		fmt.Fprintf(cli.Out(), "Pull (%d of %d): %s%s@%s\n", i+1, len(refs), repoInfo.Name(), displayTag, r.digest)
   292  
   293  		ref, err := reference.WithDigest(reference.TrimNamed(repoInfo), r.digest)
   294  		if err != nil {
   295  			return err
   296  		}
   297  		if err := imagePullPrivileged(ctx, cli, authConfig, ref.String(), requestPrivilege, false); err != nil {
   298  			return err
   299  		}
   300  
   301  		tagged, err := reference.WithTag(repoInfo, r.name)
   302  		if err != nil {
   303  			return err
   304  		}
   305  		trustedRef, err := reference.WithDigest(reference.TrimNamed(repoInfo), r.digest)
   306  		if err != nil {
   307  			return err
   308  		}
   309  		if err := TagTrusted(ctx, cli, trustedRef, tagged); err != nil {
   310  			return err
   311  		}
   312  	}
   313  	return nil
   314  }
   315  
   316  // imagePullPrivileged pulls the image and displays it to the output
   317  func imagePullPrivileged(ctx context.Context, cli *command.DockerCli, authConfig types.AuthConfig, ref string, requestPrivilege types.RequestPrivilegeFunc, all bool) error {
   318  
   319  	encodedAuth, err := command.EncodeAuthToBase64(authConfig)
   320  	if err != nil {
   321  		return err
   322  	}
   323  	options := types.ImagePullOptions{
   324  		RegistryAuth:  encodedAuth,
   325  		PrivilegeFunc: requestPrivilege,
   326  		All:           all,
   327  	}
   328  
   329  	responseBody, err := cli.Client().ImagePull(ctx, ref, options)
   330  	if err != nil {
   331  		return err
   332  	}
   333  	defer responseBody.Close()
   334  
   335  	return jsonmessage.DisplayJSONMessagesToStream(responseBody, cli.Out(), nil)
   336  }
   337  
   338  func trustDirectory() string {
   339  	return filepath.Join(cliconfig.ConfigDir(), "trust")
   340  }
   341  
   342  // certificateDirectory returns the directory containing
   343  // TLS certificates for the given server. An error is
   344  // returned if there was an error parsing the server string.
   345  func certificateDirectory(server string) (string, error) {
   346  	u, err := url.Parse(server)
   347  	if err != nil {
   348  		return "", err
   349  	}
   350  
   351  	return filepath.Join(cliconfig.ConfigDir(), "tls", u.Host), nil
   352  }
   353  
   354  func trustServer(index *registrytypes.IndexInfo) (string, error) {
   355  	if s := os.Getenv("DOCKER_CONTENT_TRUST_SERVER"); s != "" {
   356  		urlObj, err := url.Parse(s)
   357  		if err != nil || urlObj.Scheme != "https" {
   358  			return "", fmt.Errorf("valid https URL required for trust server, got %s", s)
   359  		}
   360  
   361  		return s, nil
   362  	}
   363  	if index.Official {
   364  		return registry.NotaryServer, nil
   365  	}
   366  	return "https://" + index.Name, nil
   367  }
   368  
   369  type simpleCredentialStore struct {
   370  	auth types.AuthConfig
   371  }
   372  
   373  func (scs simpleCredentialStore) Basic(u *url.URL) (string, string) {
   374  	return scs.auth.Username, scs.auth.Password
   375  }
   376  
   377  func (scs simpleCredentialStore) RefreshToken(u *url.URL, service string) string {
   378  	return scs.auth.IdentityToken
   379  }
   380  
   381  func (scs simpleCredentialStore) SetRefreshToken(*url.URL, string, string) {
   382  }
   383  
   384  // GetNotaryRepository returns a NotaryRepository which stores all the
   385  // information needed to operate on a notary repository.
   386  // It creates an HTTP transport providing authentication support.
   387  // TODO: move this too
   388  func GetNotaryRepository(streams command.Streams, repoInfo *registry.RepositoryInfo, authConfig types.AuthConfig, actions ...string) (*client.NotaryRepository, error) {
   389  	server, err := trustServer(repoInfo.Index)
   390  	if err != nil {
   391  		return nil, err
   392  	}
   393  
   394  	var cfg = tlsconfig.ClientDefault()
   395  	cfg.InsecureSkipVerify = !repoInfo.Index.Secure
   396  
   397  	// Get certificate base directory
   398  	certDir, err := certificateDirectory(server)
   399  	if err != nil {
   400  		return nil, err
   401  	}
   402  	logrus.Debugf("reading certificate directory: %s", certDir)
   403  
   404  	if err := registry.ReadCertsDirectory(cfg, certDir); err != nil {
   405  		return nil, err
   406  	}
   407  
   408  	base := &http.Transport{
   409  		Proxy: http.ProxyFromEnvironment,
   410  		Dial: (&net.Dialer{
   411  			Timeout:   30 * time.Second,
   412  			KeepAlive: 30 * time.Second,
   413  			DualStack: true,
   414  		}).Dial,
   415  		TLSHandshakeTimeout: 10 * time.Second,
   416  		TLSClientConfig:     cfg,
   417  		DisableKeepAlives:   true,
   418  	}
   419  
   420  	// Skip configuration headers since request is not going to Docker daemon
   421  	modifiers := registry.DockerHeaders(command.UserAgent(), http.Header{})
   422  	authTransport := transport.NewTransport(base, modifiers...)
   423  	pingClient := &http.Client{
   424  		Transport: authTransport,
   425  		Timeout:   5 * time.Second,
   426  	}
   427  	endpointStr := server + "/v2/"
   428  	req, err := http.NewRequest("GET", endpointStr, nil)
   429  	if err != nil {
   430  		return nil, err
   431  	}
   432  
   433  	challengeManager := challenge.NewSimpleManager()
   434  
   435  	resp, err := pingClient.Do(req)
   436  	if err != nil {
   437  		// Ignore error on ping to operate in offline mode
   438  		logrus.Debugf("Error pinging notary server %q: %s", endpointStr, err)
   439  	} else {
   440  		defer resp.Body.Close()
   441  
   442  		// Add response to the challenge manager to parse out
   443  		// authentication header and register authentication method
   444  		if err := challengeManager.AddResponse(resp); err != nil {
   445  			return nil, err
   446  		}
   447  	}
   448  
   449  	creds := simpleCredentialStore{auth: authConfig}
   450  	tokenHandler := auth.NewTokenHandler(authTransport, creds, repoInfo.FullName(), actions...)
   451  	basicHandler := auth.NewBasicHandler(creds)
   452  	modifiers = append(modifiers, transport.RequestModifier(auth.NewAuthorizer(challengeManager, tokenHandler, basicHandler)))
   453  	tr := transport.NewTransport(base, modifiers...)
   454  
   455  	return client.NewNotaryRepository(
   456  		trustDirectory(),
   457  		repoInfo.FullName(),
   458  		server,
   459  		tr,
   460  		getPassphraseRetriever(streams),
   461  		trustpinning.TrustPinConfig{})
   462  }
   463  
   464  func getPassphraseRetriever(streams command.Streams) notary.PassRetriever {
   465  	aliasMap := map[string]string{
   466  		"root":     "root",
   467  		"snapshot": "repository",
   468  		"targets":  "repository",
   469  		"default":  "repository",
   470  	}
   471  	baseRetriever := passphrase.PromptRetrieverWithInOut(streams.In(), streams.Out(), aliasMap)
   472  	env := map[string]string{
   473  		"root":     os.Getenv("DOCKER_CONTENT_TRUST_ROOT_PASSPHRASE"),
   474  		"snapshot": os.Getenv("DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE"),
   475  		"targets":  os.Getenv("DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE"),
   476  		"default":  os.Getenv("DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE"),
   477  	}
   478  
   479  	return func(keyName string, alias string, createNew bool, numAttempts int) (string, bool, error) {
   480  		if v := env[alias]; v != "" {
   481  			return v, numAttempts > 1, nil
   482  		}
   483  		// For non-root roles, we can also try the "default" alias if it is specified
   484  		if v := env["default"]; v != "" && alias != data.CanonicalRootRole {
   485  			return v, numAttempts > 1, nil
   486  		}
   487  		return baseRetriever(keyName, alias, createNew, numAttempts)
   488  	}
   489  }
   490  
   491  // TrustedReference returns the canonical trusted reference for an image reference
   492  func TrustedReference(ctx context.Context, cli *command.DockerCli, ref reference.NamedTagged) (reference.Canonical, error) {
   493  	repoInfo, err := registry.ParseRepositoryInfo(ref)
   494  	if err != nil {
   495  		return nil, err
   496  	}
   497  
   498  	// Resolve the Auth config relevant for this server
   499  	authConfig := command.ResolveAuthConfig(ctx, cli, repoInfo.Index)
   500  
   501  	notaryRepo, err := GetNotaryRepository(cli, repoInfo, authConfig, "pull")
   502  	if err != nil {
   503  		fmt.Fprintf(cli.Out(), "Error establishing connection to trust repository: %s\n", err)
   504  		return nil, err
   505  	}
   506  
   507  	t, err := notaryRepo.GetTargetByName(ref.Tag(), releasesRole, data.CanonicalTargetsRole)
   508  	if err != nil {
   509  		return nil, err
   510  	}
   511  	// Only list tags in the top level targets role or the releases delegation role - ignore
   512  	// all other delegation roles
   513  	if t.Role != releasesRole && t.Role != data.CanonicalTargetsRole {
   514  		return nil, notaryError(repoInfo.FullName(), fmt.Errorf("No trust data for %s", ref.Tag()))
   515  	}
   516  	r, err := convertTarget(t.Target)
   517  	if err != nil {
   518  		return nil, err
   519  
   520  	}
   521  
   522  	return reference.WithDigest(reference.TrimNamed(ref), r.digest)
   523  }
   524  
   525  func convertTarget(t client.Target) (target, error) {
   526  	h, ok := t.Hashes["sha256"]
   527  	if !ok {
   528  		return target{}, errors.New("no valid hash, expecting sha256")
   529  	}
   530  	return target{
   531  		name:   t.Name,
   532  		digest: digest.NewDigestFromHex("sha256", hex.EncodeToString(h)),
   533  		size:   t.Length,
   534  	}, nil
   535  }
   536  
   537  // TagTrusted tags a trusted ref
   538  func TagTrusted(ctx context.Context, cli *command.DockerCli, trustedRef reference.Canonical, ref reference.NamedTagged) error {
   539  	fmt.Fprintf(cli.Out(), "Tagging %s as %s\n", trustedRef.String(), ref.String())
   540  
   541  	return cli.Client().ImageTag(ctx, trustedRef.String(), ref.String())
   542  }
   543  
   544  // notaryError formats an error message received from the notary service
   545  func notaryError(repoName string, err error) error {
   546  	switch err.(type) {
   547  	case *json.SyntaxError:
   548  		logrus.Debugf("Notary syntax error: %s", err)
   549  		return fmt.Errorf("Error: no trust data available for remote repository %s. Try running notary server and setting DOCKER_CONTENT_TRUST_SERVER to its HTTPS address?", repoName)
   550  	case signed.ErrExpired:
   551  		return fmt.Errorf("Error: remote repository %s out-of-date: %v", repoName, err)
   552  	case trustmanager.ErrKeyNotFound:
   553  		return fmt.Errorf("Error: signing keys for remote repository %s not found: %v", repoName, err)
   554  	case storage.NetworkError:
   555  		return fmt.Errorf("Error: error contacting notary server: %v", err)
   556  	case storage.ErrMetaNotFound:
   557  		return fmt.Errorf("Error: trust data missing for remote repository %s or remote repository not found: %v", repoName, err)
   558  	case trustpinning.ErrRootRotationFail, trustpinning.ErrValidationFail, signed.ErrInvalidKeyType:
   559  		return fmt.Errorf("Warning: potential malicious behavior - trust data mismatch for remote repository %s: %v", repoName, err)
   560  	case signed.ErrNoKeys:
   561  		return fmt.Errorf("Error: could not find signing keys for remote repository %s, or could not decrypt signing key: %v", repoName, err)
   562  	case signed.ErrLowVersion:
   563  		return fmt.Errorf("Warning: potential malicious behavior - trust data version is lower than expected for remote repository %s: %v", repoName, err)
   564  	case signed.ErrRoleThreshold:
   565  		return fmt.Errorf("Warning: potential malicious behavior - trust data has insufficient signatures for remote repository %s: %v", repoName, err)
   566  	case client.ErrRepositoryNotExist:
   567  		return fmt.Errorf("Error: remote trust data does not exist for %s: %v", repoName, err)
   568  	case signed.ErrInsufficientSignatures:
   569  		return fmt.Errorf("Error: could not produce valid signature for %s.  If Yubikey was used, was touch input provided?: %v", repoName, err)
   570  	}
   571  
   572  	return err
   573  }