rpccookieperms: Allow setting setxid/sticky bits

Simply for backward compatibility

Author: luke-jr

src/util/fs_helpers.cpp

@@ -306,8 +306,7 @@ static std::optional<unsigned> StringToOctal(const std::string& str)
 
 static auto ConvertPermsToOctal(const std::string& str) noexcept -> std::optional<unsigned>
 {
-    // Don't permit setting special bits as they're not relevant to cookie files
-    if (str.length() == 3) return StringToOctal(str);
+    if ((str.length() == 3) || (str.length() == 4)) return StringToOctal(str);
     return std::nullopt;
 }
 

test/functional/rpc_users.py

@@ -93,8 +93,9 @@ def test_rpccookieperms(self):
             "group": 0o640,
             "all": 0o644,
             "440": 0o440,
-            "640": 0o640,
+            "0640": 0o640,
             "444": 0o444,
+            "1660": 0o1660,
         }
 
         if platform.system() == 'Windows':
@@ -104,7 +105,7 @@ def test_rpccookieperms(self):
         self.log.info('Check cookie file permissions can be set using -rpccookieperms')
 
         cookie_file_path = self.nodes[1].chain_path / '.cookie'
-        PERM_BITS_UMASK = 0o777
+        PERM_BITS_UMASK = 0o7777
 
         def test_perm(perm: Optional[str]):
             if not perm: