SCRAM.error should be within standardised errors (put raw in self.raw_error)

modules/sasl/scram.py

@@ -7,6 +7,20 @@ import base64, enum, hashlib, hmac, os, typing
 ALGORITHMS = [
     "MD5", "SHA-1", "SHA-224", "SHA-256", "SHA-384", "SHA-512"]
 
+SCRAM_ERRORS = [
+    "invalid-encoding",
+    "extensions-not-supported", # unrecognized 'm' value
+    "invalid-proof",
+    "channel-bindings-dont-match",
+    "server-does-support-channel-binding",
+    "channel-binding-not-supported",
+    "unsupported-channel-binding-type",
+    "unknown-user",
+    "invalid-username-encoding", # invalid utf8 of bad SASLprep
+    "no-resources",
+    "other-error"
+]
+
 def _scram_nonce() -> bytes:
     return base64.b64encode(os.urandom(32))
 def _scram_escape(s: bytes) -> bytes:
@@ -38,6 +52,7 @@ class SCRAM(object):
 
         self.state = SCRAMState.Uninitialised
         self.error = ""
+        self.raw_error = ""
 
         self._client_first = b""
         self._salted_password = b""
@@ -93,7 +108,13 @@ class SCRAM(object):
     def server_final(self, data: bytes) -> bool:
         pieces = self._get_pieces(data)
         if b"e" in pieces:
-            self.error = pieces[b"e"].decode("utf8")
+            error = pieces[b"e"].decode("utf8")
+            self.raw_error = error
+            if error in SCRAM_ERRORS:
+                self.error = error
+            else:
+                self.error = "other-error"
+
             self.state = SCRAMState.Failed
             return False