return if the PIN is not a match, and hash the PIN before saving it

common/pin.go

@@ -1,6 +1,10 @@
 package common
 
-import "regexp"
+import (
+	"regexp"
+
+	"golang.org/x/crypto/bcrypt"
+)
 
 // Define the regex pattern as a constant
 const (
@@ -12,3 +16,18 @@ func IsValidPIN(pin string) bool {
 	match, _ := regexp.MatchString(pinPattern, pin)
 	return match
 }
+
+// HashPIN uses bcrypt with 8 salt rounds to hash the PIN
+func HashPIN(pin string) (string, error) {
+	hash, err := bcrypt.GenerateFromPassword([]byte(pin), 8)
+	if err != nil {
+		return "", err
+	}
+	return string(hash), nil
+}
+
+// VerifyPIN compareS the hashed PIN with the plaintext PIN
+func VerifyPIN(hashedPIN, pin string) bool {
+	err := bcrypt.CompareHashAndPassword([]byte(hashedPIN), []byte(pin))
+	return err == nil
+}

internal/handlers/ussd/menuhandler.go

@@ -356,11 +356,19 @@ func (h *Handlers) ConfirmPinChange(ctx context.Context, sym string, input []byt
 		res.FlagReset = append(res.FlagReset, flag_pin_mismatch)
 	} else {
 		res.FlagSet = append(res.FlagSet, flag_pin_mismatch)
+		return res, nil
 	}
-	// If matched, save the confirmed PIN as the new account PIN
-	err = store.WriteEntry(ctx, sessionId, common.DATA_ACCOUNT_PIN, []byte(temporaryPin))
+
+	// Hash the PIN
+	hashedPIN, err := common.HashPIN(string(temporaryPin))
 	if err != nil {
-		logg.ErrorCtxf(ctx, "failed to write temporaryPin entry with", "key", common.DATA_ACCOUNT_PIN, "value", temporaryPin, "error", err)
+		logg.ErrorCtxf(ctx, "failed to hash temporaryPin", "error", err)
+	}
+
+	// save the hashed PIN as the new account PIN
+	err = store.WriteEntry(ctx, sessionId, common.DATA_ACCOUNT_PIN, []byte(hashedPIN))
+	if err != nil {
+		logg.ErrorCtxf(ctx, "failed to write DATA_ACCOUNT_PIN entry with", "key", common.DATA_ACCOUNT_PIN, "hashedPIN value", hashedPIN, "error", err)
 		return res, err
 	}
 	return res, nil
@@ -392,11 +400,18 @@ func (h *Handlers) VerifyCreatePin(ctx context.Context, sym string, input []byte
 		res.FlagSet = append(res.FlagSet, flag_pin_set)
 	} else {
 		res.FlagSet = []uint32{flag_pin_mismatch}
+		return res, nil
 	}
 
-	err = store.WriteEntry(ctx, sessionId, common.DATA_ACCOUNT_PIN, []byte(temporaryPin))
+	// Hash the PIN
+	hashedPIN, err := common.HashPIN(string(temporaryPin))
 	if err != nil {
-		logg.ErrorCtxf(ctx, "failed to write temporaryPin entry with", "key", common.DATA_ACCOUNT_PIN, "value", temporaryPin, "error", err)
+		logg.ErrorCtxf(ctx, "failed to hash temporaryPin", "error", err)
+	}
+
+	err = store.WriteEntry(ctx, sessionId, common.DATA_ACCOUNT_PIN, []byte(hashedPIN))
+	if err != nil {
+		logg.ErrorCtxf(ctx, "failed to write DATA_ACCOUNT_PIN entry with", "key", common.DATA_ACCOUNT_PIN, "value", hashedPIN, "error", err)
 		return res, err
 	}