fix: incorrect conversion between integer types (#49)

Signed-off-by: Chris Gianelloni <wolf31o2@blinklabs.io>
Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

serialization/HDWallet/HDWallet.go

@@ -158,7 +158,7 @@ func (hd *HDWallet) DerivePath(path string) (*HDWallet, error) {
 	derived_wallet := hd.copy()
 	for _, index := range strings.Split(strings.TrimLeft(path, "m/"), "/") {
 		if strings.HasSuffix(index, "'") {
-			ind_val, err := strconv.Atoi(string(index[:len(index)-1]))
+			ind_val, err := strconv.ParseUint(string(index[:len(index)-1]), 10, 32)
 
 			if err != nil {
 				return nil, err
@@ -167,7 +167,7 @@ func (hd *HDWallet) DerivePath(path string) (*HDWallet, error) {
 				uint32(ind_val), true,
 			)
 		} else {
-			ind_val, err := strconv.Atoi(index)
+			ind_val, err := strconv.ParseUint(index, 10, 32)
 			if err != nil {
 				return nil, err
 			}
@@ -200,7 +200,7 @@ func (hd *HDWallet) Derive(index uint32, hardened bool) *HDWallet {
 	return &HDWallet{
 		RootXprivKey: hd.RootXprivKey,
 		XPrivKey:     derived_xprivkey,
-		Path:         hd.Path + "/" + strconv.Itoa(int(index)),
+		Path:         hd.Path + "/" + strconv.FormatUint(uint64(index), 10),
 		Seed:         hd.Seed,
 		Mnemonic:     hd.Mnemonic,
 		Passphrase:   hd.Passphrase,

serialization/common.go

@@ -3,6 +3,7 @@ package serialization
 import (
 	"encoding/hex"
 	"fmt"
+	"math"
 	"reflect"
 	"strconv"
 
@@ -116,6 +117,9 @@ func (cb *CustomBytes) Int() (int, error) {
 		if err != nil {
 			return 0, err
 		}
+		if value < math.MinInt || value > math.MaxInt {
+			return 0, fmt.Errorf("value out of int range")
+		}
 		return int(value), nil
 	}
 	return 0, fmt.Errorf("not int")