1 files changed, 123 insertions, 0 deletions
diff --git a/cmd/fscrypt/protector.go b/cmd/fscrypt/protector.go
new file mode 100644
index 0000000..e77a2e3
--- /dev/null
+++ b/cmd/fscrypt/protector.go
@@ -0,0 +1,123 @@
+/*
+ * protector.go - Functions for creating and getting action.Protectors which
+ * ensure that login passphrases are on the correct filesystem.
+ *
+ * Copyright 2017 Google Inc.
+ * Author: Joe Richey (joerichey@google.com)
+ *
+ * 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 (
+	"log"
+
+	"fscrypt/actions"
+	"fscrypt/filesystem"
+	"fscrypt/metadata"
+)
+
+// createProtector makes a new protector on either ctx.Mount or if the requested
+// source is a pam_passphrase, creates it on the root filesystem. Prompts for
+// user input are used to get the source, name and keys.
+func createProtectorFromContext(ctx *actions.Context) (*actions.Protector, error) {
+	if err := promptForSource(ctx); err != nil {
+		return nil, err
+	}
+	log.Printf("using source: %s", ctx.Config.Source.String())
+
+	name, err := promptForName(ctx)
+	if err != nil {
+		return nil, err
+	}
+	log.Printf("using name: %s", name)
+
+	// We only want to create new login protectors on the root filesystem.
+	// So we make a new context if necessary.
+	if ctx.Config.Source == metadata.SourceType_pam_passphrase && ctx.Mount.Path != "/" {
+		log.Printf("creating login protector on %q instead of %q", "/", ctx.Mount.Path)
+		if ctx, err = modifiedContext(ctx); err != nil {
+			return nil, err
+		}
+	}
+
+	return actions.CreateProtector(ctx, name, createKeyFn)
+}
+
+// selectExistingProtector returns a locked Protector which corresponds to an
+// options in the non-empty slice of options. Prompts for user input are used to
+// get the keys and select the option.
+func selectExistingProtector(ctx *actions.Context, options []*actions.ProtectorOption) (*actions.Protector, error) {
+	idx, err := promptForProtector(options)
+	if err != nil {
+		return nil, err
+	}
+	option := options[idx]
+
+	log.Printf("using %s", formatInfo(option.ProtectorInfo))
+	return actions.GetProtectorFromOption(ctx, option)
+}
+
+// expandedProtectorOptions gets all the actions.ProtectorOptions for ctx.Mount
+// as well as any pam_passphrase protectors for the root filesystem.
+func expandedProtectorOptions(ctx *actions.Context) ([]*actions.ProtectorOption, error) {
+	options, err := ctx.ProtectorOptions()
+	if err != nil {
+		return nil, err
+	}
+
+	// Do nothing different if we are at the root, or cannot load the root.
+	if ctx.Mount.Path == "/" {
+		return options, nil
+	}
+	if ctx, err = modifiedContext(ctx); err != nil {
+		log.Print(err)
+		return options, nil
+	}
+	rootOptions, err := ctx.ProtectorOptions()
+	if err != nil {
+		log.Print(err)
+		return options, nil
+	}
+	log.Print("adding additional ProtectorOptions")
+
+	// Keep track of what we have seen, so we don't have duplicates
+	seenOptions := make(map[string]bool)
+	for _, option := range options {
+		seenOptions[option.Descriptor()] = true
+	}
+
+	for _, option := range rootOptions {
+		// Add in unseen passphrase protectors on the root filesystem
+		// to the options list as potential linked protectors.
+		if option.Source() == metadata.SourceType_pam_passphrase &&
+			!seenOptions[option.Descriptor()] {
+			option.LinkedMount = ctx.Mount
+			options = append(options, option)
+		}
+	}
+
+	return options, nil
+}
+
+// modifiedContext returns a copy of ctx with the mountpoint replaced by that of
+// the root filesystem.
+func modifiedContext(ctx *actions.Context) (*actions.Context, error) {
+	mnt, err := filesystem.GetMount("/")
+	if err != nil {
+		return nil, err
+	}
+
+	return &actions.Context{Config: ctx.Config, Mount: mnt}, nil
+}