Add path validation in Resolver.ResolvePath

Add ErrNoComponents in ParsePath validation & remove redundant path
validation.
Any lines using core.Resolve & Resolver.ResolvePath will have their path
validated.

License: MIT
Signed-off-by: rht <rhtbot@gmail.com>

path.go

@@ -61,12 +61,15 @@ func ParsePath(txt string) (Path, error) {
 	}
 
 	if parts[0] != "" {
-		return "", ErrBadPath
+		if _, err := ParseKeyToPath(parts[0]); err != nil {
+			return "", ErrBadPath
+		}
+		// The case when the path starts with hash without a protocol prefix
+		return Path("/ipfs/" + txt), nil
 	}
 
 	if parts[1] == "ipfs" {
-		_, err := ParseKeyToPath(parts[2])
-		if err != nil {
+		if _, err := ParseKeyToPath(parts[2]); err != nil {
 			return "", err
 		}
 	} else if parts[1] != "ipns" {
@@ -77,13 +80,16 @@ func ParsePath(txt string) (Path, error) {
 }
 
 func ParseKeyToPath(txt string) (Path, error) {
+	if txt == "" {
+		return "", ErrNoComponents
+	}
+
 	chk := b58.Decode(txt)
 	if len(chk) == 0 {
 		return "", errors.New("not a key")
 	}
 
-	_, err := mh.Cast(chk)
-	if err != nil {
+	if _, err := mh.Cast(chk); err != nil {
 		return "", err
 	}
 	return FromKey(key.Key(chk)), nil

resolver.go

@@ -65,6 +65,11 @@ func SplitAbsPath(fpath Path) (mh.Multihash, []string, error) {
 // ResolvePath fetches the node for given path. It returns the last item
 // returned by ResolvePathComponents.
 func (s *Resolver) ResolvePath(ctx context.Context, fpath Path) (*merkledag.Node, error) {
+	// validate path
+	if err := fpath.IsValid(); err != nil {
+		return nil, err
+	}
+
 	nodes, err := s.ResolvePathComponents(ctx, fpath)
 	if err != nil || nodes == nil {
 		return nil, err