Show public key identities before importing (#427)

Fixes #425

action/clihelper.go

@@ -196,15 +196,15 @@ func (s *Action) askForPassword(ctx context.Context, name string, askFn func(con
 }
 
 // AskForKeyImport asks for permissions to import the named key
-func (s *Action) AskForKeyImport(ctx context.Context, key string) bool {
+func (s *Action) AskForKeyImport(ctx context.Context, key string, names []string) bool {
 	if ctxutil.IsAlwaysYes(ctx) {
 		return true
 	}
 	if !ctxutil.IsInteractive(ctx) {
 		return false
 	}
 
-	ok, err := s.askForBool(ctx, fmt.Sprintf("Do you want to import the public key '%s' into your keyring?", key), false)
+	ok, err := s.askForBool(ctx, fmt.Sprintf("Do you want to import the public key '%s' (Names: %+v) into your keyring?", key, names), false)
 	if err != nil {
 		return false
 	}

store/store.go

@@ -7,7 +7,7 @@ type RecipientCallback func(context.Context, string, []string) ([]string, error)
 
 // ImportCallback is a callback to ask the user if he wants to import
 // a certain recipients public key into his keystore
-type ImportCallback func(context.Context, string) bool
+type ImportCallback func(context.Context, string, []string) bool
 
 // FsckCallback is a callback to ask the user to confirm certain fsck
 // corrective actions

store/sub/context.go

@@ -119,7 +119,7 @@ func HasImportFunc(ctx context.Context) bool {
 func GetImportFunc(ctx context.Context) store.ImportCallback {
 	imf, ok := ctx.Value(ctxKeyImportFunc).(store.ImportCallback)
 	if !ok || imf == nil {
-		return func(context.Context, string) bool {
+		return func(context.Context, string, []string) bool {
 			return true
 		}
 	}

store/sub/gpg.go

@@ -2,13 +2,15 @@ package sub
 
 import (
 	"context"
+	"fmt"
 	"os"
 	"path/filepath"
 
 	"github.com/blang/semver"
 	"github.com/justwatchcom/gopass/utils/fsutil"
 	"github.com/justwatchcom/gopass/utils/out"
 	"github.com/pkg/errors"
+	"golang.org/x/crypto/openpgp"
 )
 
 // GPGVersion returns parsed GPG version information
@@ -38,10 +40,17 @@ func (s *Store) ImportMissingPublicKeys(ctx context.Context) error {
 			continue
 		}
 
+		// get info about this public key
+		names, err := s.decodePublicKey(ctx, r)
+		if err != nil {
+			out.Red(ctx, "[%s] Failed to decode public key %s: %s", s.alias, r, err)
+			continue
+		}
+
 		// we need to ask the user before importing
 		// any key material into his keyring!
 		if imf := GetImportFunc(ctx); imf != nil {
-			if !imf(ctx, r) {
+			if !imf(ctx, r, names) {
 				continue
 			}
 		}
@@ -90,6 +99,34 @@ func (s *Store) exportPublicKey(ctx context.Context, r string) (string, error) {
 	return filename, nil
 }
 
+func (s *Store) decodePublicKey(ctx context.Context, r string) ([]string, error) {
+	filename := filepath.Join(s.path, keyDir, r)
+	if !fsutil.IsFile(filename) {
+		return nil, errors.Errorf("Public Key %s not found at %s", r, filename)
+	}
+
+	fh, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		_ = fh.Close()
+	}()
+
+	el, err := openpgp.ReadArmoredKeyRing(fh)
+	if err != nil {
+		return nil, err
+	}
+	if len(el) != 1 {
+		return nil, fmt.Errorf("Public Key must contain exactly one Entity")
+	}
+	names := make([]string, 0, len(el[0].Identities))
+	for _, v := range el[0].Identities {
+		names = append(names, v.Name)
+	}
+	return names, nil
+}
+
 // import an public key into the default keyring
 func (s *Store) importPublicKey(ctx context.Context, r string) error {
 	filename := filepath.Join(s.path, keyDir, r)