From b7c2419aede2447accdb0bf7f609b1c60942cdbf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Anders=20=C3=85berg?= <anders@andersaberg.com>
Date: Fri, 11 Apr 2025 09:10:41 +0200
Subject: [PATCH] Fix base64url decode on MacOS passkeys (#14227)

* Add support for padding in base64url decode

* whitespace

* whitespace
---
 .../desktop_native/objc/src/native/utils.m     | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/apps/desktop/desktop_native/objc/src/native/utils.m b/apps/desktop/desktop_native/objc/src/native/utils.m
index 040c723a8ac..7ae84696312 100644
--- a/apps/desktop/desktop_native/objc/src/native/utils.m
+++ b/apps/desktop/desktop_native/objc/src/native/utils.m
@@ -18,9 +18,25 @@ NSString *serializeJson(NSDictionary *dictionary, NSError *error) {
 }
 
 NSData *decodeBase64URL(NSString *base64URLString) {
+  if (base64URLString.length == 0) {
+    return nil;
+  }
+  
+  // Replace URL-safe characters with standard base64 characters
   NSString *base64String = [base64URLString stringByReplacingOccurrencesOfString:@"-" withString:@"+"];
   base64String = [base64String stringByReplacingOccurrencesOfString:@"_" withString:@"/"];
-
+  
+  // Add padding if needed
+  NSUInteger paddingLength = 4 - (base64String.length % 4);
+  if (paddingLength < 4) {
+    NSMutableString *paddedString = [NSMutableString stringWithString:base64String];
+    for (NSUInteger i = 0; i < paddingLength; i++) {
+      [paddedString appendString:@"="];
+    }
+    base64String = paddedString;
+  }
+  
+  // Decode the string
   NSData *nsdataFromBase64String = [[NSData alloc]
     initWithBase64EncodedString:base64String options:0];