context: Ensure context name is valid on import

Signed-off-by: Chris Crone <christopher.crone@docker.com>

cli/command/context/cmd.go

@@ -1,10 +1,6 @@
 package context
 
 import (
-	"errors"
-	"fmt"
-	"regexp"
-
 	"github.com/docker/cli/cli"
 	"github.com/docker/cli/cli/command"
 	"github.com/spf13/cobra"
@@ -30,20 +26,3 @@ func NewContextCommand(dockerCli command.Cli) *cobra.Command {
 	)
 	return cmd
 }
-
-const restrictedNamePattern = "^[a-zA-Z0-9][a-zA-Z0-9_.+-]+$"
-
-var restrictedNameRegEx = regexp.MustCompile(restrictedNamePattern)
-
-func validateContextName(name string) error {
-	if name == "" {
-		return errors.New("context name cannot be empty")
-	}
-	if name == "default" {
-		return errors.New(`"default" is a reserved context name`)
-	}
-	if !restrictedNameRegEx.MatchString(name) {
-		return fmt.Errorf("context name %q is invalid, names are validated against regexp %q", name, restrictedNamePattern)
-	}
-	return nil
-}

cli/command/context/create.go

@@ -137,7 +137,7 @@ func createNewContext(o *CreateOptions, stackOrchestrator command.Orchestrator,
 }
 
 func checkContextNameForCreation(s store.Reader, name string) error {
-	if err := validateContextName(name); err != nil {
+	if err := store.ValidateContextName(name); err != nil {
 		return err
 	}
 	if _, err := s.GetMetadata(name); !store.IsErrContextDoesNotExist(err) {

cli/command/context/export.go

@@ -77,7 +77,7 @@ func writeTo(dockerCli command.Cli, reader io.Reader, dest string) error {
 
 // RunExport exports a Docker context
 func RunExport(dockerCli command.Cli, opts *ExportOptions) error {
-	if err := validateContextName(opts.ContextName); err != nil && opts.ContextName != command.DefaultContextName {
+	if err := store.ValidateContextName(opts.ContextName); err != nil && opts.ContextName != command.DefaultContextName {
 		return err
 	}
 	ctxMeta, err := dockerCli.ContextStore().GetMetadata(opts.ContextName)

cli/command/context/update.go

@@ -68,7 +68,7 @@ func newUpdateCommand(dockerCli command.Cli) *cobra.Command {
 
 // RunUpdate updates a Docker context
 func RunUpdate(cli command.Cli, o *UpdateOptions) error {
-	if err := validateContextName(o.Name); err != nil {
+	if err := store.ValidateContextName(o.Name); err != nil {
 		return err
 	}
 	s := cli.ContextStore()

cli/command/context/use.go

@@ -5,6 +5,7 @@ import (
 	"os"
 
 	"github.com/docker/cli/cli/command"
+	"github.com/docker/cli/cli/context/store"
 	"github.com/spf13/cobra"
 )
 
@@ -23,7 +24,7 @@ func newUseCommand(dockerCli command.Cli) *cobra.Command {
 
 // RunUse set the current Docker context
 func RunUse(dockerCli command.Cli, name string) error {
-	if err := validateContextName(name); err != nil && name != "default" {
+	if err := store.ValidateContextName(name); err != nil && name != "default" {
 		return err
 	}
 	if _, err := dockerCli.ContextStore().GetMetadata(name); err != nil && name != "default" {

cli/context/store/store.go

@@ -13,6 +13,7 @@ import (
 	"net/http"
 	"path"
 	"path/filepath"
+	"regexp"
 	"strings"
 
 	"github.com/docker/docker/errdefs"
@@ -20,6 +21,10 @@ import (
 	"github.com/pkg/errors"
 )
 
+const restrictedNamePattern = "^[a-zA-Z0-9][a-zA-Z0-9_.+-]+$"
+
+var restrictedNameRegEx = regexp.MustCompile(restrictedNamePattern)
+
 // Store provides a context store for easily remembering endpoints configuration
 type Store interface {
 	Reader
@@ -184,6 +189,20 @@ func (s *store) GetStorageInfo(contextName string) StorageInfo {
 	}
 }
 
+// ValidateContextName checks a context name is valid.
+func ValidateContextName(name string) error {
+	if name == "" {
+		return errors.New("context name cannot be empty")
+	}
+	if name == "default" {
+		return errors.New(`"default" is a reserved context name`)
+	}
+	if !restrictedNameRegEx.MatchString(name) {
+		return fmt.Errorf("context name %q is invalid, names are validated against regexp %q", name, restrictedNamePattern)
+	}
+	return nil
+}
+
 // Export exports an existing namespace into an opaque data stream
 // This stream is actually a tarball containing context metadata and TLS materials, but it does
 // not map 1:1 the layout of the context store (don't try to restore it manually without calling store.Import)
@@ -427,6 +446,9 @@ func parseMetadata(data []byte, name string) (Metadata, error) {
 	if err := json.Unmarshal(data, &meta); err != nil {
 		return meta, err
 	}
+	if err := ValidateContextName(name); err != nil {
+		return Metadata{}, err
+	}
 	meta.Name = name
 	return meta, nil
 }

cli/context/store/storeconfig_test.go

@@ -45,3 +45,16 @@ func TestValidFilePaths(t *testing.T) {
 		assert.Equal(t, err == nil, expectedValid, "%q should report valid as: %v", p, expectedValid)
 	}
 }
+
+func TestValidateContextName(t *testing.T) {
+	names := map[string]bool{
+		"../../invalid/escape": false,
+		"/invalid/absolute":    false,
+		`\invalid\windows`:     false,
+		"validname":            true,
+	}
+	for n, expectedValid := range names {
+		err := ValidateContextName(n)
+		assert.Equal(t, err == nil, expectedValid, "%q should report valid as: %v", n, expectedValid)
+	}
+}