ICS 24 Implementation

x/ibc/23-commitment/types/merkle.go

@@ -1,12 +1,14 @@
 package types
 
 import (
+	"fmt"
 	"strings"
 
 	"github.com/tendermint/tendermint/crypto/merkle"
 
 	"github.com/cosmos/cosmos-sdk/store/rootmulti"
 	"github.com/cosmos/cosmos-sdk/x/ibc/23-commitment/exported"
+	validation "github.com/cosmos/cosmos-sdk/x/ibc/24-validation"
 )
 
 // ICS 023 Merkle Types Implementation
@@ -104,6 +106,9 @@ func (p Path) String() string {
 // CONTRACT: provided path string MUST be a well formated path. See ICS24 for
 // reference.
 func ApplyPrefix(prefix exported.PrefixI, path string) Path {
+	if !validation.DefaultPathValidator(path) {
+		panic(fmt.Sprintf("Path: %s is malformed", path))
+	}
 	// Split paths by the separator
 	pathSlice := strings.Split(path, "/")
 	commitmentPath := NewPath(pathSlice)

x/ibc/24-validation/validate.go

@@ -0,0 +1,61 @@
+package validation
+
+import (
+	"regexp"
+	"strings"
+)
+
+// regular expression to check string is lowercase alphabetic characters only
+var isAlphaLower = regexp.MustCompile(`^[a-z]+$`).MatchString
+
+// regular expression to check string is alphanumeric
+var isAlphaNumeric = regexp.MustCompile(`^[a-zA-Z0-9]+$`).MatchString
+
+// Validator function type to validate path and identifier bytestrings
+type Validator func(string) bool
+
+// Default validator function for Client, Connection, and Channel
+// identifiers
+// Valid Identifier must be between 10-20 characters and only
+// contain lowercase alphabetic characters
+func DefaultIdentifierValidator(id string) bool {
+	// valid id must be between 10 and 20 characters
+	if len(id) < 10 || len(id) > 20 {
+		return false
+	}
+	// valid id must contain only lower alphabetic characters
+	if !isAlphaLower(string(id)) {
+		return false
+	}
+	return true
+}
+
+// NewPathValidator takes in a Identifier Validator function and returns
+// a Path Validator function which requires path only has valid identifiers
+// alphanumeric character strings, and "/" separators
+func NewPathValidator(idValidator Validator) Validator {
+	return func(path string) bool {
+		pathArr := strings.Split(path, "/")
+		for _, p := range pathArr {
+			// Each path element must either be valid identifier or alphanumeric
+			if !idValidator(p) && !isAlphaNumeric(p) {
+				return false
+			}
+		}
+		return true
+	}
+}
+
+// Default Path Validator takes in path string and validates
+// with default identifier rules. This is optimized by simply
+// checking that all path elements are alphanumeric
+func DefaultPathValidator(path string) bool {
+	pathArr := strings.Split(path, "/")
+	for _, p := range pathArr {
+		// Each path element must either be alphanumeric
+		if !isAlphaNumeric(p) {
+			return false
+		}
+	}
+	return true
+}