From 685e9d2e69cbb1c7780f63310232f1ae2b71b96d Mon Sep 17 00:00:00 2001
From: Bryan Frimin <bryan@getprobo.com>
Date: Sun, 19 Apr 2026 15:00:32 +0200
Subject: [PATCH] Fix non-constant-time string != comparison

Signed-off-by: Bryan Frimin <bryan@getprobo.com>
---
 pkg/securecookie/securecookie.go     | 3 ++-
 pkg/securetoken/securetoken.go       | 3 ++-
 pkg/statelesstoken/statelesstoken.go | 3 ++-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/pkg/securecookie/securecookie.go b/pkg/securecookie/securecookie.go
index 6704f162f..1491bbbb6 100644
--- a/pkg/securecookie/securecookie.go
+++ b/pkg/securecookie/securecookie.go
@@ -17,6 +17,7 @@ package securecookie
 import (
 	"crypto/hmac"
 	"crypto/sha256"
+	"crypto/subtle"
 	"encoding/base64"
 	"errors"
 	"fmt"
@@ -143,7 +144,7 @@ func Verify(signedValue, secret string) (string, error) {
 		return "", fmt.Errorf("cannot sign value: %w", err)
 	}
 
-	if signedValue != expectedSignedValue {
+	if subtle.ConstantTimeCompare([]byte(signedValue), []byte(expectedSignedValue)) != 1 {
 		return "", ErrInvalidSignature
 	}
 
diff --git a/pkg/securetoken/securetoken.go b/pkg/securetoken/securetoken.go
index 14f5b20ab..ddfea0cc2 100644
--- a/pkg/securetoken/securetoken.go
+++ b/pkg/securetoken/securetoken.go
@@ -17,6 +17,7 @@ package securetoken
 import (
 	"crypto/hmac"
 	"crypto/sha256"
+	"crypto/subtle"
 	"encoding/base64"
 	"errors"
 	"fmt"
@@ -83,7 +84,7 @@ func Verify(signedValue, secret string) (string, error) {
 		return "", fmt.Errorf("cannot sign value: %w", err)
 	}
 
-	if signedValue != expectedSignedValue {
+	if subtle.ConstantTimeCompare([]byte(signedValue), []byte(expectedSignedValue)) != 1 {
 		return "", ErrInvalidSignature
 	}
 
diff --git a/pkg/statelesstoken/statelesstoken.go b/pkg/statelesstoken/statelesstoken.go
index e7ae2a749..15f7802fc 100644
--- a/pkg/statelesstoken/statelesstoken.go
+++ b/pkg/statelesstoken/statelesstoken.go
@@ -17,6 +17,7 @@ package statelesstoken
 import (
 	"crypto/hmac"
 	"crypto/sha256"
+	"crypto/subtle"
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
@@ -133,7 +134,7 @@ func ValidateToken[T any](secret string, tokenType string, tokenString string) (
 	h.Write([]byte(encodedPayload))
 	expectedSignature := base64.RawURLEncoding.EncodeToString(h.Sum(nil))
 
-	if providedSignature != expectedSignature {
+	if subtle.ConstantTimeCompare([]byte(providedSignature), []byte(expectedSignature)) != 1 {
 		return nil, &ErrInvalidToken{message: "invalid token signature"}
 	}