config: guard against privkey being overwritten in fsrepo setConfig

License: MIT
Signed-off-by: Jeromy <why@ipfs.io>

core/commands/config.go

@@ -163,28 +163,12 @@ included in the output of this command.
 			return
 		}
 
-		idmap, ok := cfg["Identity"].(map[string]interface{})
-		if !ok {
-			res.SetError(errors.New("config has no identity"), cmds.ErrNormal)
+		err = scrubValue(cfg, []string{config.IdentityTag, config.PrivKeyTag})
+		if err != nil {
+			res.SetError(err, cmds.ErrNormal)
 			return
 		}
 
-		privKeyKey := "" // make sure we both find the name of privkey and we delete it
-		for key, _ := range idmap {
-			if strings.ToLower(key) == "privkey" {
-				if privKeyKey != "" {
-					res.SetError(errors.New("found multiple PrivKey keys"), cmds.ErrNormal)
-					return
-				}
-				privKeyKey = key
-			}
-		}
-		if privKeyKey == "" {
-			res.SetError(errors.New("haven't found PriveKey key"), cmds.ErrNormal)
-		}
-
-		delete(idmap, privKeyKey)
-
 		output, err := config.HumanOutput(cfg)
 		if err != nil {
 			res.SetError(err, cmds.ErrNormal)
@@ -195,6 +179,47 @@ included in the output of this command.
 	},
 }
 
+func scrubValue(m map[string]interface{}, key []string) error {
+	find := func(m map[string]interface{}, k string) (string, interface{}, bool) {
+		lckey := strings.ToLower(k)
+		for mkey, val := range m {
+			lcmkey := strings.ToLower(mkey)
+			if lckey == lcmkey {
+				return mkey, val, true
+			}
+		}
+		return "", nil, false
+	}
+
+	cur := m
+	for _, k := range key[:len(key)-1] {
+		foundk, val, ok := find(cur, k)
+		if !ok {
+			return fmt.Errorf("failed to find specified key")
+		}
+
+		if foundk != k {
+			// case mismatch, calling this an error
+			return fmt.Errorf("case mismatch in config, expected %q but got %q", k, foundk)
+		}
+
+		mval, mok := val.(map[string]interface{})
+		if !mok {
+			return fmt.Errorf("%s was not a map", foundk)
+		}
+
+		cur = mval
+	}
+
+	todel, _, ok := find(cur, key[len(key)-1])
+	if !ok {
+		return fmt.Errorf("%s, not found", strings.Join(key, "."))
+	}
+
+	delete(cur, todel)
+	return nil
+}
+
 var configEditCmd = &cmds.Command{
 	Helptext: cmds.HelpText{
 		Tagline: "Opens the config file for editing in $EDITOR.",
@@ -265,19 +290,10 @@ func getConfig(r repo.Repo, key string) (*ConfigField, error) {
 }
 
 func setConfig(r repo.Repo, key string, value interface{}) (*ConfigField, error) {
-	keyF, err := getConfig(r, "Identity.PrivKey")
-	if err != nil {
-		return nil, errors.New("failed to get PrivKey")
-	}
-	privkey := keyF.Value
-	err = r.SetConfigKey(key, value)
+	err := r.SetConfigKey(key, value)
 	if err != nil {
 		return nil, fmt.Errorf("failed to set config value: %s (maybe use --json?)", err)
 	}
-	err = r.SetConfigKey("Identity.PrivKey", privkey)
-	if err != nil {
-		return nil, errors.New("failed to set PrivKey")
-	}
 	return getConfig(r, key)
 }
 
@@ -301,7 +317,7 @@ func replaceConfig(r repo.Repo, file io.Reader) error {
 		return errors.New("setting private key with API is not supported")
 	}
 
-	keyF, err := getConfig(r, "Identity.PrivKey")
+	keyF, err := getConfig(r, config.PrivKeySelector)
 	if err != nil {
 		return fmt.Errorf("Failed to get PrivKey")
 	}

repo/config/identity.go

@@ -5,6 +5,10 @@ import (
 	ic "gx/ipfs/QmUWER4r4qMvaCnX5zREcfyiWN7cXN9g3a7fkRqNz8qWPP/go-libp2p-crypto"
 )
 
+const IdentityTag = "Identity"
+const PrivKeyTag = "PrivKey"
+const PrivKeySelector = IdentityTag + "." + PrivKeyTag
+
 // Identity tracks the configuration of the local node's identity.
 type Identity struct {
 	PeerID  string

repo/fsrepo/fsrepo.go

@@ -482,6 +482,14 @@ func (r *FSRepo) SetConfigKey(key string, value interface{}) error {
 		return err
 	}
 
+	// Load private key to guard against it being overwritten.
+	// NOTE: this is a temporary measure to secure this field until we move
+	// keys out of the config file.
+	pkval, err := common.MapGetKV(mapconf, config.PrivKeySelector)
+	if err != nil {
+		return err
+	}
+
 	// Get the type of the value associated with the key
 	oldValue, err := common.MapGetKV(mapconf, key)
 	ok := true
@@ -523,6 +531,11 @@ func (r *FSRepo) SetConfigKey(key string, value interface{}) error {
 		return err
 	}
 
+	// replace private key, in case it was overwritten.
+	if err := common.MapSetKV(mapconf, "Identity.PrivKey", pkval); err != nil {
+		return err
+	}
+
 	// This step doubles as to validate the map against the struct
 	// before serialization
 	conf, err := config.FromMap(mapconf)