Merge pull request 'hash-pin' (#235) from hash-pin into master

Reviewed-on: #235

common/pin.go

@@ -0,0 +1,33 @@
+package common
+
+import (
+	"regexp"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// Define the regex pattern as a constant
+const (
+	pinPattern = `^\d{4}$`
+)
+
+// checks whether the given input is a 4 digit number
+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
+}

common/pin_test.go

@@ -0,0 +1,173 @@
+package common
+
+import (
+	"testing"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+func TestIsValidPIN(t *testing.T) {
+	tests := []struct {
+		name     string
+		pin      string
+		expected bool
+	}{
+		{
+			name:     "Valid PIN with 4 digits",
+			pin:      "1234",
+			expected: true,
+		},
+		{
+			name:     "Valid PIN with leading zeros",
+			pin:      "0001",
+			expected: true,
+		},
+		{
+			name:     "Invalid PIN with less than 4 digits",
+			pin:      "123",
+			expected: false,
+		},
+		{
+			name:     "Invalid PIN with more than 4 digits",
+			pin:      "12345",
+			expected: false,
+		},
+		{
+			name:     "Invalid PIN with letters",
+			pin:      "abcd",
+			expected: false,
+		},
+		{
+			name:     "Invalid PIN with special characters",
+			pin:      "12@#",
+			expected: false,
+		},
+		{
+			name:     "Empty PIN",
+			pin:      "",
+			expected: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			actual := IsValidPIN(tt.pin)
+			if actual != tt.expected {
+				t.Errorf("IsValidPIN(%q) = %v; expected %v", tt.pin, actual, tt.expected)
+			}
+		})
+	}
+}
+
+func TestHashPIN(t *testing.T) {
+	tests := []struct {
+		name string
+		pin  string
+	}{
+		{
+			name: "Valid PIN with 4 digits",
+			pin:  "1234",
+		},
+		{
+			name: "Valid PIN with leading zeros",
+			pin:  "0001",
+		},
+		{
+			name: "Empty PIN",
+			pin:  "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			hashedPIN, err := HashPIN(tt.pin)
+			if err != nil {
+				t.Errorf("HashPIN(%q) returned an error: %v", tt.pin, err)
+				return
+			}
+
+			if hashedPIN == "" {
+				t.Errorf("HashPIN(%q) returned an empty hash", tt.pin)
+			}
+
+			// Ensure the hash can be verified with bcrypt
+			err = bcrypt.CompareHashAndPassword([]byte(hashedPIN), []byte(tt.pin))
+			if tt.pin != "" && err != nil {
+				t.Errorf("HashPIN(%q) produced a hash that does not match: %v", tt.pin, err)
+			}
+		})
+	}
+}
+
+func TestVerifyMigratedHashPin(t *testing.T) {
+	tests := []struct {
+		pin  string
+		hash string
+	}{
+		{
+			pin:  "1234",
+			hash: "$2b$08$dTvIGxCCysJtdvrSnaLStuylPoOS/ZLYYkxvTeR5QmTFY3TSvPQC6",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.pin, func(t *testing.T) {
+			ok := VerifyPIN(tt.hash, tt.pin)
+			if !ok {
+				t.Errorf("VerifyPIN could not verify migrated PIN: %v", tt.pin)
+			}
+		})
+	}
+}
+
+func TestVerifyPIN(t *testing.T) {
+	tests := []struct {
+		name       string
+		pin        string
+		hashedPIN  string
+		shouldPass bool
+	}{
+		{
+			name:       "Valid PIN verification",
+			pin:        "1234",
+			hashedPIN:  hashPINHelper("1234"),
+			shouldPass: true,
+		},
+		{
+			name:       "Invalid PIN verification with incorrect PIN",
+			pin:        "5678",
+			hashedPIN:  hashPINHelper("1234"),
+			shouldPass: false,
+		},
+		{
+			name:       "Invalid PIN verification with empty PIN",
+			pin:        "",
+			hashedPIN:  hashPINHelper("1234"),
+			shouldPass: false,
+		},
+		{
+			name:       "Invalid PIN verification with invalid hash",
+			pin:        "1234",
+			hashedPIN:  "invalidhash",
+			shouldPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := VerifyPIN(tt.hashedPIN, tt.pin)
+			if result != tt.shouldPass {
+				t.Errorf("VerifyPIN(%q, %q) = %v; expected %v", tt.hashedPIN, tt.pin, result, tt.shouldPass)
+			}
+		})
+	}
+}
+
+// Helper function to hash a PIN for testing purposes
+func hashPINHelper(pin string) string {
+	hashedPIN, err := HashPIN(pin)
+	if err != nil {
+		panic("Failed to hash PIN for test setup: " + err.Error())
+	}
+	return hashedPIN
+}

internal/handlers/ussd/menuhandler.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"fmt"
 	"path"
-	"regexp"
 	"strconv"
 	"strings"
 
@@ -34,17 +33,6 @@ var (
 	translationDir = path.Join(scriptDir, "locale")
 )
 
-// Define the regex patterns as constants
-const (
-	pinPattern = `^\d{4}$`
-)
-
-// checks whether the given input is a 4 digit number
-func isValidPIN(pin string) bool {
-	match, _ := regexp.MatchString(pinPattern, pin)
-	return match
-}
-
 // FlagManager handles centralized flag management
 type FlagManager struct {
 	parser *asm.FlagParser
@@ -281,7 +269,7 @@ func (h *Handlers) VerifyNewPin(ctx context.Context, sym string, input []byte) (
 	flag_valid_pin, _ := h.flagManager.GetFlag("flag_valid_pin")
 	pinInput := string(input)
 	// Validate that the PIN is a 4-digit number.
-	if isValidPIN(pinInput) {
+	if common.IsValidPIN(pinInput) {
 		res.FlagSet = append(res.FlagSet, flag_valid_pin)
 	} else {
 		res.FlagReset = append(res.FlagReset, flag_valid_pin)
@@ -306,7 +294,7 @@ func (h *Handlers) SaveTemporaryPin(ctx context.Context, sym string, input []byt
 	accountPIN := string(input)
 
 	// Validate that the PIN is a 4-digit number.
-	if !isValidPIN(accountPIN) {
+	if !common.IsValidPIN(accountPIN) {
 		res.FlagSet = append(res.FlagSet, flag_incorrect_pin)
 		return res, nil
 	}
@@ -368,11 +356,20 @@ 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)
+		return res, 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
@@ -404,11 +401,19 @@ 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)
+		return res, 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
 	}
 
@@ -722,7 +727,7 @@ func (h *Handlers) Authorize(ctx context.Context, sym string, input []byte) (res
 		return res, err
 	}
 	if len(input) == 4 {
-		if bytes.Equal(input, AccountPin) {
+		if common.VerifyPIN(string(AccountPin), string(input)) {
 			if h.st.MatchFlag(flag_account_authorized, false) {
 				res.FlagReset = append(res.FlagReset, flag_incorrect_pin)
 				res.FlagSet = append(res.FlagSet, flag_allow_update, flag_account_authorized)
@@ -949,7 +954,15 @@ func (h *Handlers) ResetOthersPin(ctx context.Context, sym string, input []byte)
 		logg.ErrorCtxf(ctx, "failed to read temporaryPin entry with", "key", common.DATA_TEMPORARY_VALUE, "error", err)
 		return res, err
 	}
-	err = store.WriteEntry(ctx, string(blockedPhonenumber), common.DATA_ACCOUNT_PIN, []byte(temporaryPin))
+
+	// Hash the PIN
+	hashedPIN, err := common.HashPIN(string(temporaryPin))
+	if err != nil {
+		logg.ErrorCtxf(ctx, "failed to hash temporaryPin", "error", err)
+		return res, err
+	}
+
+	err = store.WriteEntry(ctx, string(blockedPhonenumber), common.DATA_ACCOUNT_PIN, []byte(hashedPIN))
 	if err != nil {
 		return res, nil
 	}
@@ -1400,7 +1413,6 @@ func (h *Handlers) GetCurrentProfileInfo(ctx context.Context, sym string, input
 		defaultValue = "Not Provided"
 	}
 
-
 	sm, _ := h.st.Where()
 	parts := strings.SplitN(sm, "_", 2)
 	filename := parts[1]

internal/handlers/ussd/menuhandler_test.go

@@ -1047,7 +1047,14 @@ func TestAuthorize(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			err = store.WriteEntry(ctx, sessionId, common.DATA_ACCOUNT_PIN, []byte(accountPIN))
+			// Hash the PIN
+			hashedPIN, err := common.HashPIN(accountPIN)
+			if err != nil {
+				logg.ErrorCtxf(ctx, "failed to hash temporaryPin", "error", err)
+				t.Fatal(err)
+			}
+
+			err = store.WriteEntry(ctx, sessionId, common.DATA_ACCOUNT_PIN, []byte(hashedPIN))
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -1499,59 +1506,6 @@ func TestQuit(t *testing.T) {
 	}
 }
 
-func TestIsValidPIN(t *testing.T) {
-	tests := []struct {
-		name     string
-		pin      string
-		expected bool
-	}{
-		{
-			name:     "Valid PIN with 4 digits",
-			pin:      "1234",
-			expected: true,
-		},
-		{
-			name:     "Valid PIN with leading zeros",
-			pin:      "0001",
-			expected: true,
-		},
-		{
-			name:     "Invalid PIN with less than 4 digits",
-			pin:      "123",
-			expected: false,
-		},
-		{
-			name:     "Invalid PIN with more than 4 digits",
-			pin:      "12345",
-			expected: false,
-		},
-		{
-			name:     "Invalid PIN with letters",
-			pin:      "abcd",
-			expected: false,
-		},
-		{
-			name:     "Invalid PIN with special characters",
-			pin:      "12@#",
-			expected: false,
-		},
-		{
-			name:     "Empty PIN",
-			pin:      "",
-			expected: false,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			actual := isValidPIN(tt.pin)
-			if actual != tt.expected {
-				t.Errorf("isValidPIN(%q) = %v; expected %v", tt.pin, actual, tt.expected)
-			}
-		})
-	}
-}
-
 func TestValidateAmount(t *testing.T) {
 	fm, err := NewFlagManager(flagsPath)
 	if err != nil {